Fermentation Quality of Herbal Tea Residue and its Application in Fattening Cattle Under Heat Stress

doi:10.21203/rs.3.rs-852242/v1

Download PDF

Research Article

Fermentation Quality of Herbal Tea Residue and its Application in Fattening Cattle Under Heat Stress

https://doi.org/10.21203/rs.3.rs-852242/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 12 Nov, 2021

Read the published version in BMC Veterinary Research →

You are reading this latest preprint version

Background: Herbal tea residue (HTR) is generally considered to be the waste of herbal tea beverage production while it still retains rich nutrients and active substances. The main aim of the present study was to investigate the effect of fermentation technology on improving the quality of HTRs, and focus on the fermented HTR-induced alleviation of summer heat stress in fattening cattle.

Results: In this study, the waste HTR was fermented and then fed to a total of 45 fattening cattles that were divided into 3 groups (fermented HTR replaced 0%, 15%, 30% of Pennisetum purpureum respectively), and the feeding experiment was lasted for 40 days. The physiological indexes, growth performance and fecal microorganisms of fattening cattle were evaluated and results showed that fermented HTR could effectively reduce the respiratory rate and rectal temperature of fattening cattle under heat stress, increase the daily feed intake and daily gain, and improve the antioxidant content and blood immune index. In addition, we studied the fecal microorganisms composition of 6 fattening cattles in each group and found fermented HTR significantly changed the composition of fecal microorganisms and increased microbial diversity, and correlation analysis suggested that the bacteria were closely related to fecal SCFA levels of fattening cattle under heat stress.

Conclusions: we suggested that 30% of fermented HTR can help maintain health of fattening cattle and alleviate the heat stress of fattening cattle by the change of intestine microorganisms.

Veterinary Epidemiology

herbal tea residue

microorganism

fattening cattle

fermented feed

heat stress

Herbal medicine has a long history of being used to prevent and treat diseases in China [1]. Studies have shown that drinking herbal tea can help to relieve heat in the body and the symptoms of sore throat caused by summer heat stress [2]. Herbal tea drinks are consumed widely because of their natural ingredients, convenient drinking, and unique health benefits [3–5]. In some areas, such as Guangdong, China, drinking herbal tea has even become part of the culture [6]. More and more people are consuming herbal tea drinks, requiring large scale tea production and resulting in large amounts of HTR [7]. In the past, most of tea residues were regarded as waste and were burned or dumped into landfill [8], which was not only environmentally damaging, but also a represented a waste of resources. Fortunately, researchers are now paying attention to the resource utilization of tea residues. Researchers have found that tea residues can significantly improve the soil fertility, leading to their use as organic fertilizers [9]. In addition, tea residues have been developed as a non-conventional water adsorbent to remove water pollutants like methylene blue [10], antibiotics [11], and heavy metals, such as chromium[12], cadmium [13], copper [14], lead, zinc [15], and arsenic [16] from aqueous solutions.

Alternatively, tea residues can be used as an unconventional feed resource in animal production. Generally, during tea production, not all of the effective substances are completely dissolved, thus some tea residues still retain a good proportion of the nutrients and bioactive compounds [17]. It is reported that HTR contains many residual bioactive substances, such as phenols, polysaccharides, organic acids, alkaloids, and essential oils, which have been proven to have anti-oxidant and anti-bacterial effects [18]. Moreover, tea residues also contain protein, carbohydrate, fat, fiber, vitamins, and minerals [18]. Previous studies have used tea residues as substitutes for antibiotics to help improve the gut microbial composition of grower pigs [19]. In addition, tea residues improved the abdominal fat accumulation of broiler chickens, and had a positive impact on egg yolk quality [20]. Besides, researchers demonstrated the potential of tea residues for feeding ruminants [17]. One study concluded that tea residues could improve the antioxidant capacity of cow plasma [21]. In another study, a fermented herbal residue was fed to Holstein heifers, which effectively promoted the growth and immune performance of cows under heat stress [22].

The potential feeding value of HTRs prompted us to develop a suitable technology for animal production. Currently, to apply HTRs, problems of storage, unbalanced nutrition, and poor palatability need to be solved. Therefore, the main aim of the present study was to investigate the effect of fermentation technology on improving the quality of HTRs, and focus on the fermented HTR-induced alleviation of summer heat stress in fattening cattle.

2.1. Nutritional components and changes to the HTR after fermentation

The HTR contained a high water content (75.10%) and the dry matter content was 24.90%. As a proportion of the dry matter content, the crude protein, crude fat, and ash contents were 13.10%, 2.60%, 14.92%, respectively. In addition, HTR also contained minerals, and the contents of potassium, calcium, magnesium, phosphorus, sulfur, and chlorine were 0.61%, 1.14%, 0.40%, 0.25%, 0.21%, and 0.51%, respectively. The acid detergent fiber and neutral detergent fiber were 39.8% and 54.3%; contents of lactate, acetic acid, and butyric acid were 4.67%, 1.58%, and 0.35%, respectively; and the water soluble carbohydrate (WSC) was 3.10%. The net energy for maintenance and net energy gain of HTR were 0.79 and 0.25 Mcal/Kg, respectively (Table S1).

After fermentation, the pH value of the mixture of the HTR, oat hay, and bacteria decreased from 4.95 to 3.89. On the basis of dry matter, the crude protein in the HTR increased by 1.07% compared with that of the unfermented HTR. The contents of neutral detergent fiber and acid detergent fiber decreased by 5.82% and 4.32% respectively. The contents of lactate, acetic acid, and propionic acid increased to 1247.01, 115.41 and 8.38 mmol/g, respectively (Table 1). Compared with CN group, LC group and HC group had more abundant crude protein (11.25%, 11.32% and 11.35%, respectively). In addition, compared with CN group, LC group and HC group also had more abundant crude fat (3.15%, 3.2% and 3.22%, respectively), calcium (0.43%, 0.65% and 0.79%, respectively) and phosphorus (0.45%, 0.53% and 0.48%, respectively) (Table S1).

2.2. Temperature and humidity index in the cowshed

The daily changes in ambient temperature and THI among the three time points is shown in Figure S1. In general, the THI classification of heat stress is as follows: No heat stress when THI ≤ 72; mild heat stress when 72 < THI ≤ 79; high heat stress when 79 < THI ≤ 84; and severe heat stress when THI > 84 [23]. During the experiment, the mean THI of the barn was 81 (range 79–84), 86 (more than 84 ), and 79 (range 72–79) in the morning (08:00), afternoon (15:00), and evening (22:00), respectively. The total average THI was 82, which was between 79 < THI < 84. Therefore, we concluded that fattening cattle were in a high heat stress state during the whole period of the formal experiment.

2.3. Effects of fermented HTR on RR and RT of fattening cattle under heat stress

The daily average RR of CN group was 87.04 breaths/min, and RT was 38.84 °C; RR and RT of LC group were 83.39 breaths/min and 38.75°C, respectively; and of the HC group they were 80.23 breaths/min and 38.63°C (Table 2). Compared with the CN group, the RR and RT of LC and HC groups all decreased at the three determination times, and there were no significant differences between the LC group and CN group for the RR level. The HC group showed significantly reduced RR at 15:00 and 22:00 (P < 0.05) and a reduced rectal temperature at 8:00 and 15:00 (P < 0.05) compared with those of the CN group. At 15:00, the RT of the HC group was significantly lower than that of the LC group (P < 0.05). According to the above data, 30% fermented HTR replacement could effectively alleviate the RR and RT of fattening cattle under heat stress.

Table 2

Effects of fermented herbal tea residue feed on respiratory rate and rectal temperature of fattening cattle
Items	Time	CN	LC	HC
Respiratory rates (breaths/min)	8:00	87.12 ± 1.25	86.67 ± 1.12	85.00 ± 1.48
	15:00	87.50 ± 2.80^a	83.00 ± 2.80^ab	78.50 ± 1.00^b
	22:00	86.50 ± 3.20^a	80.50 ± 3.43^ab	77.20 ± 1.74^b
Rectal temperature (°C)	8:00	38.85 ± 0.04^a	38.75 ± 0.04^ab	38.61 ± 0.05^b
	15:00	38.88 ± 0.06^a	38.78 ± 0.05^ab	38.60 ± 0.08^c
	22:00	38.80 ± 0.05	38.73 ± 0.07	38.68 ± 0.07
Note: The values were showed as the means ± standard error (N = 15); Different letters showed significant difference (P < 0.05), while the same letter or no letter showed no significant difference (P > 0.05); HTR, herbal tea residue; CN, no herbal tea residues, the control group; LC, 15% fermented HTRs replaced, the 15% replacement group; HC, 30% fermented HTRs replaced, the 30% replacement group.

2.4 Effects of fermented HTR on feed intake and weight gain

Compared with the CN group, the feed intake and daily gain of the LC and HC increased gradually, which correlated positively with the increase in fermented HTR replacement (Table 3). The feed intake and average daily gain of the HC group were significantly higher than those of the CN group (P < 0.05). The average daily gain between the CN and LC groups showed no significant differences (P > 0.05); however, the feed intake increased significantly in the LC group (P < 0.05). In addition, fermented HTR also reduced the F/G value of fattening cattle significantly (P < 0.05). Therefore, fermented HTR could improve the feed intake and increased the feed conversion rate of fattening cattle under heat stress, and the effect of 30% fermented HTR replacement was better than that of 15%.

Table 3

Effect of fermented herbal tea residue feed on feed intake and weight gain of fattening cattle
Items	CN	LC	HC
Initial weight (kg)	518.29 ± 27.24	521.43 ± 38.45	524 ± 34.21
Final weight (kg)	542.94 ± 26.52	550.13 ± 37.35	558.33 ± 32.55
ADG (kg/day)	0.94 ± 0.05^b	1.09 ± 0.09^ab	1.26 ± 0.05^a
Feed intake (kg/day)	12.64 ± 0.21^c	13.41 ± 0.21^b	14.27 ± 0.18^a
Feed conversion ratio (F/G)	13.85 ± 1.07^a	12.61 ± 0.53^b	11.64 ± 0.40^c
Note: The values were calculated as the means ± standard error (N = 15); Different letters showed significant difference (P < 0.05), while the same letter or no letter showed no significant difference (P > 0.05), HTR, herbal tea residue; CN, no herbal tea residues, the control group; LC, 15% fermented HTRs replaced, the 15% replacement group; HC, 30% fermented HTRs replaced, the 30% replacement group.

2.5 Effects of fermented HTR on serum biochemical indexes

Compared with the fattening cattle fed with a basal diet, the levels of HSP70, COR, LDH, T-AOC, and MDA in the LC and HC groups decreased with the increase in fermented HTR, while IgG, IgA, IL-2, IL-6, ALT, AST, and SOD levels increased gradually. The HC group showed significantly reduced the levels of HSP70, Cor, and LDH in serum under heat stress (P < 0.05), and significantly increased the levels of IgG, IL-2, and SOD (P < 0.05). Compared with that in the CN group, the LDH level in the LC group was decreased significantly (P > 0.05), and T-AOC level was increased significantly (P > 0.05). The above results showed that fermented HTR replacement could improve the anti-heat stress and antioxidant capacity of fattening cattle, and the effect of 30% replacement was more obvious than that of 15% replacement (Table 4).

Table 4

Analysis of serum indices in beef cattle under heat stressed between three groups
Items	CN	LC	HC
HSP70 (ng/mL)	18.67 ± 1.17^a	17.78 ± 0.54^b	16.87 ± 1.60^c
Cor (ng/mL)	91.55 ± 1.83^a	80.96 ± 0.60^ab	72.63 ± 4.22^b
LDH (U/L)	696.00 ± 10.65^a	601.00 ± 8.97^b	583.00 ± 3.76^b
IgG (ng/mL)	7.96 ± 1.16^b	9.62 ± 0.44^ab	12.30 ± 1.18^a
IgA (ng/mL)	3.57 ± 0.24	4.29 ± 0.43	4.60 ± 0.66
IL-2 (pg/mL)	308.75 ± 2.40^c	332.81 ± 2.16^b	340.47 ± 0.43^a
IL-6 (pg/mL)	316.17 ± 15.25	327.69 ± 4.43	336.81 ± 4.80
ALT (U/L)	27.50 ± 2.02	29.50 ± 0.87	31.00 ± 3.21
AST (U/L)	78.00 ± 6.06	84.50 ± 9.49	90.25 ± 4.94
T-AOC (mmol/L)	0.27 ± 0.03^b	0.36 ± 0.01^a	0.33 ± 0.01^ab
MDA (mmol/L)	25.21 ± 1.67	24.93 ± 0.00	23.47 ± 0.85
SOD (U/mL)	48.73 ± 2.79^b	51.76 ± 0.58^ab	56.43 ± 0.20^a
T4 (ng/mL)	33.02 ± 1.06	33.47 ± 0.36	32.46 ± 0.70
Note: The values were showed as the means ± standard error (N = 6); Different letters showed significant difference (P < 0.05), while the same letter or no letter showed no significant difference (P > 0.05); Cor, Cortisol; LDH, Lactate dehydrogenase; IgA, Immunoglobulin A; IgG, Immunoglobulin G; IL-2, Interleukin-2; IL-6, Interleukin-6; ALT, Alanine aminotransferase; AST, Aspartate aminotransferase; T-AOC, Total antioxidant capacity; MDA, Malondialdehyde; SOD, Superoxide dismutase; T4, Thyroxine. HTR, Herbal tea residue; CN, no herbal tea residues, the control group; LC, 15% fermented HTRs replaced, the 15% replacement group; HC, 30% fermented HTRs replaced, the 30% replacement group.

Compared with that in the CN group, 30% fermented HTR could reduce blood glucose significantly, and 15% and 30% fermented HTR replacement could increase the content of total protein and albumin significantly. The content of blood urea nitrogen and total cholesterol (T-CHO) decreased with the increase in fermented HTR, while triglyceride (TG) showed the opposite reaction. There were no significant differences in blood urea nitrogen (BUN), T-CHO, and TG among the three treatments (Table 5).

Table 5

Effect of fermented herbal tea residue on biochemical indicators of fattening cattle during summer heat stressed
Items	CN	LC	HC
Glu (mmol/L)	2.09 ± 0.008^a	2.06 ± 0.03^ab	1.99 ± 0.006^b
TP (g/L)	67.27 ± 2.15^b	74.87 ± 0.67^a	77.25 ± 1.01^a
ALB (g/L)	32.23 ± 0.65^b	33.67 ± 0.52^a	36.65 ± 1.88^a
BUN (mmol/L)	3.35 ± 0.31	3.04 ± 0.17610	2.69 ± 0.07
T-CHO (mmol/L)	2.72 ± 0.20	2.34 ± 0.28	2.46 ± 0.02
TG (mmol/L)	0.127 ± 0.03	0.14 ± 0.01	0.15 ± 0.009
Note: The values were showed as the means ± standard error (N = 6); Different letters showed significant difference (P < 0.05), while the same letter or no letter showed no significant difference (P > 0.05); Glu, Glucose; ALB, Albumin; TP, Total protein; BUN, blood urea nitrogen; T-CHO, Total cholesterol; TG, Triglyceride; HTR, Herbal tea residue; CN, no herbal tea residues, the control group; LC, 15% fermented HTRs replaced, the 15% replacement group; HC, 30% fermented HTRs replaced, the 30% replacement group.

2.6. 16S rRNA gene sequencing and annotation analysis

We extracted the genomic DNA of 12 fecal samples from CN group and HC group, and amplified the corresponding 16S DNA V3-V4 fragment. After sequencing, the CN group produced an average of 89,720 raw reads and the HC group produced an average of 90,069 raw reads. After splicing, the CN group produced an average of 88,745 combined reads and the average combined percentage was 98.92%. The HC group produced an average of 88,679 combined reads and the average combined percentage was 98.47%. After filtering low quality and short length fragments, the number of tag sequences for subsequent analysis were 58,016 nochime reads in the CN group, with an average effective rate of 64.93%, and 58,636 nochime reads in the HC group, with an average effective rate of 65.21% (Table S2A). The CN group data generated 1,451 OTUs and the HC group generated 1,446 OTUs on average (Table S2B). There were 669 core OTUs in the 12 samples (Fig. 1A); with 319 unique OTUs in the CN group and 297 OTUs in the HC group, while there were 1,786 shared OTUs between the two groups (Fig. 1B; Table S2C).

The relative abundance of the top 10 fecal microbiota at the phylum level in each sample and group is shown Fig. 1C and Fig. 1D. The most abundant bacteria at the phylum level were Firmicutes and Bacteroidetes within and between the CN and HC groups. The average percentage of Firmicutes in HC group was 59.54%, which was significantly higher than that in the CN group (52.94%) (P < 0.01). The average percentage of Bacteroidetes in the HC group was 31.87%, which was significantly lower than that in the CN group (37.87%) (P < 0.01). The annotated counts and percentages at the class, order, family, genus, and species levels are show in Table S3 and S4.

Observed species, the Shannon index, the Simpson index, Chao1, ACE, Good’s coverage, and PD whole tree reflected the richness and diversity of species in the samples. The species richness of the HC group was slightly higher than that of the CN group, but there was no significant difference (P > 0.05) (Table 6). The PCA between the groups is shown in Fig. 2A. We found that CN and HC groups samples were separated from each other, which reflected the influence of HTR substitution on microbial community changes. Similar results were obtained and showed in Fig. 2B. The UPGMA clustering tree was shown in Fig. 2C, which confirmed the significant structural separation of the fecal microflora between the two groups by measuring the similarity of microbial communities according to the degree of their overlap.

Table 6

Statistical analysis of sample complexity
Item	CN	HC	P vaule
Observed species	1260.50 ± 15.1805	1265.50 ± 16.5726	0.828
Shannon	8.02 ± 0.0537	8.07 ± 0.0668	0.564
Simpson	0.99 ± 0.0006	0.99 ± 0.0010	0.568
Chao1	1316.69 ± 16.97	1319.46 ± 17.83	0.913
Ace	1321.61 ± 18.36	1320.44 ± 17.79	0.964
Goods coverage	0.99 ± 0.0001	0.99 ± 0.0001	0.334
PD whole tree	85.54 ± 2.3358	93.59 ± 2.7638	0.05
Note: Alpha diversity reflected the richness and diversity of species in samples, and it has a variety of indicators: observed species, shannon, simpson, chao1, ace, goods coverage, PD whole tree. The higher the value of Observed species, the higher the species richness are. Shannon index evaluates the richness and evenness of species composition in the sample. The greater the value, the more abundant and evenly distributed the species are. The Chao1 and ACE indices measure species richness. Goods coverage index represents sequencing depth. PD whole tree index reflects phylogenetic diversity. HTR, herbal tea residue; CN, no herbal tea residues, the control group; HC, 30% fermented HTRs replaced, the 30% replacement group.

The data in Table S5 show that the levels the Bacteroidia and Clostridia in the HC group were significantly lower and higher, respectively, than those in the CN group at the class level (P < 0.01), while the Bacteroidales and Clostridiales (P < 0.01) showed the same trend at the order level. At the family level, the Rikenellaceae and Paludibacteraceae levels were decreased in the HC group (P < 0.01 and P < 0.05), and the Ruminocaceae levels were increased (P < 0.05). At the genus level, Erysipelotrichaceae levels in the HC group increased (P < 0.01), and Fournierella, Acetobacterium, Anaerovorax, Butyrivibrio, and Oscillibacter levels in the HC group were also higher than those in the CN group (P < 0.05), whereas, the Alistipes levels were lower (P < 0.05). At the species level, the rumen_bacterium_NK4A214 were enriched in the HC group (P < 0.05). LEFSe identified 29 differentially abundant taxonomic clades in the CN and HC groups, whose LDA scores were greater than 2.0 (Fig. 3). The results showed that at the phylum level, the Bacteroidetes were enriched in the CN group, while the Fibrobacteres and Firmicutes were enriched in the HC group.

2.7. Fecal SCFAs concentration and their correlation with microbiota genera

SCFAs are the main products of microbial metabolism in the intestines, and the types and quantity of SCFAs are regulated by microbial species, diet, and the environment [24]. As shown in Table 7, the SCFAs of the fecal microorganisms in the CN, LC and HC groups showed different trends. The concentration of Aa increased gradually with the increase in fermented HTR substitution, at 13.33, 13.37, and 14.82 mol/g in the three groups, respectively. The Aa content in the HC group was significantly higher than that in the CN and LC groups. The concentrations of Pa (3.29, 3.46, and 3.542 mol/g, respectively), Ba (2.35, 2.51, and 2.49 mol/g, respectively), and Va (0.09, 0.09, and 0.10 mol/g, respectively) increased in the fermented HTR replacement groups, without statistical significance among the groups. The concentrations of Ia were 0.15, 0.13, and 0.17 mol/g, respectively, with the concentrations in HC group being significantly higher than those in the CN and LC groups. However, the concentration of Iva (0.22, 0.18, and 0.18 mol/g, respectively) decreased gradually, and the levels in the LC and HC groups were significantly lower than those in the CN group. We also studied the correlation between SCFAs and significantly enriched fecal microbiota at the genus level. As shown in Fig. 4, there was a significant positive correlation between Aa and the relative abundance of Acetobacterium (P < 0.01), and a positive correlation with the relative abundance of Anaerovorax (P = 0.05). In addition, there was a positive correlation between Pa and the relative abundance of Acetobacterium (P < 0.05), Erysipelotrichaceae (P < 0.05), and Fournierella (P < 0.05). However, there was no significant relationship between Ia, Ba, Iva, Va, and Acetobacterium, Alistipes, Anaerovorax, Butyrivibrio, Erysipelotrichaceae, Fournierella, or Oscillibacter (P > 0.05).

Table 7

Effect of fermented herbal tea residue on the content of short chain fatty acids (SCFAs) in feces of fattening cattle(mol/g)༈N = 6༉
Item	CN	LC	HC
Acetic acid	13.33 ± 0.91^b	13.37 ± 1.27^b	14.82 ± 0.95^a
Propionic acid	3.29 ± 0.22	3.46 ± 0.63	3.54 ± 0.26
Isobutyric acid	0.15 ± 0.01^b	0.13 ± 0.01^b	0.17 ± 0.02^a
Butyric acid	2.35 ± 0.16	2.51 ± 0.22	2.49 ± 0.21
Isovaleric acid	0.22 ± 0.03^a	0.18 ± 0.02^b	0.18 ± 0.02^b
Valeric acid	0.09 ± 0.01	0.09 ± 0.01	0.10 ± 0.02
Note: The values were showed as the means ± standard error (N = 6); Different letters showed significant difference (P < 0.05), while the same letter or no letter showed no significant difference (P > 0.05); CN, no herbal tea residues, the control group; LC, 15% fermented HTRs replaced, the 15% replacement group; HC, 30% fermented HTRs replaced, the 30% replacement group.

HTR is the residual water-insoluble substance produced by herbal tea beverage, which has the potential to be used as feed [22]. Compared with corn silage with a crude protein content of 7–9% [17], in this experiment, HTR contained more crude protein (13.10%). Thus, HTR is a potential protein source to replace corn silage feed [25]. HTR was also rich in fat, with a higher content than many energy feeds, such as wheat and paddy. Ruminants requires a dietary crude fiber content of at least 17% [26], and HTR was rich in crude fiber, indicating that HTR could also be used as a source of ruminant roughage. To improve the palatability of HTR and solve the problem of storage, we fermented the HTR. However, the content of neutral detergent fiber was higher than 54% and the content of water soluble carbohydrate (WSC) was only 3.10%, which was not conducive to fermentation alone [27]. The addition of molasses increased the WSC of fermented materials [28], and oat grass was beneficial to reduce the total water content and promote the fermentation quality. In addition, complex bacteria were added to help fermentation. Previous studies have shown that Bacillus subtilis grows strongly and can inhibit the growth of other aerobic and harmful microorganisms during the fermentation process. At the same time, it can produce rich metabolites, such as organic acids and bioactive substances. During fermentation, Bacillus subtilis also produces a large number of enzymes [29]. Yeast is suitable for growth in acidic and humid environments containing sugar. Yeast can use monosaccharides or oligosaccharides produced in fermentation to produce alcohol and carbon dioxide, which is one of the best combination fermentation strains. Lactobacillus can inhibit the growth of spoilage bacteria, reduce the pH, maintain an acidic environment, and ensure the fermentation quality [30]. After fermentation, the content of lactic acid, acetic acid, and propionic acid increased, and the pH decreased to 3.89, which effectively inhibited the reproduction of undesirable bacteria, increased the content of crude protein, and decreased the content of crude fiber, indicating a better fermentation quality. Previous study found that green tea residue silage could be used as a protein source for lactating dairy cows to replace part of the alfalfa and soybean meal in their diet, which had no adverse effect on the performance of the dairy cows [25], suggesting that fermented HTR could be used as feed resource.

In the subtropical region of southern China, the climate is hot in summer; therefore, beef cattle are vulnerable to summer heat stress, which affects their eating and health [31]. This results in growth retardation, which affects the development of the beef cattle industry [32]. It has been reported that heat stress can reduce the intake of feed and affect the metabolism after absorption [33]. The temperature and humidity index reflects the heat stress intensity of animals by measuring the temperature and humidity index of the breeding environment [34]. Our results showed that the total average THI was 82, which was between 79 < THI < 84. Therefore, we concluded that the fattening cattle were in a high heat stress state during the whole period of the formal experiment. RR and RT are indices used to quantify the physiological changes of animals under heat stress [35]. Replacement with fermented HTR was beneficial to reduce the RT and RR of fattening cattle in the heat stress environment, with the 30% fermented HTR having a more significant effect. This suggested that fermented HTR could alleviate heat stress symptoms of fattening cattle in summer, which is consistent with the results of other studies [36–38]. Chen found that Chinese herbal medicine could reduce significantly the RR of beef cattle under heat stress [37]. Song found that Chinese herbal medicine could reduce the RT for a certain period of time under high temperature [36]. When animals are exposed to heat stress, they eat less to reduce their heat production [38], which ultimately affects their growth and fattening.

Cor is a hormone secreted by the adrenal gland during stress. When the body is in the state of heat stress, it will stimulate the adrenal cortex to secrete Cor to adapt to the adverse environment [39]. Our results showed that in the heat stress environment, with the increase in fermented HTR in the diet, the amount of Cor secreted by the fattening cattle decreased gradually, indicating that fermented HTR could effectively alleviate the heat stress response of fattening cattle. This was consistent with the results of Song et al., who found that Chinese herbal medicine could reduce the secretion of Cor in beef cattle under heat stress [36] and this might be explained by the fact that herbal medicine active substances are retained in the HTR, which can relieve heat stress in summer. LDH participates in glycolysis. Hocking et al. found that high heat treatment can increase LDH activity [40]. AST and ALT reflect the liver function of animals. When the liver is damaged, the contents of these two enzymes in serum increase. It has been reported that ALT increases significantly in hot and dry seasons, which might reflect the negative effects of heat stress on liver tissue [41]. Our results showed that LDH, AST, and ALT levels decreased with the increase in fermented HTR, indicating that fermented HTR could alleviate the damage caused by heat stress in fattening cattle.

Thyroxine T3 and T4 can promote metabolism and increase the body's heat production [42]. Our findings showed that the thyroid function of beef cattle decreased and the amount of T4 secreted by the thyroid gland decreased, thus reducing heat production and improving the body's adaptability to the thermal environment. Chen and other researchers applied Chinese herbal medicine to heat stressed beef cattle, and also found that the level of T4 decreased, demonstrating that Chinese herbal medicine can alleviate the heat stress of beef cattle [37].

When the animals are in the state of heat stress for a long time, the body's immunity will decline [43]. IgG is the most abundant immunoglobulin in animal organs, which can protect the body from infection, and is an important immune index under heat stress [44]. Interleukin-2 (IL-2) is a cell growth factor in the immune system of the body, and is also an important indicator of cellular immune function under heat stress [45]. Furthermore, IL-6 is a proinflammatory cytokine that is associated with an increased inflammatory response [46]. Studies have shown that HTR can enhance the immune function of the human body [47]. In the present study, we found that the levels of IgG and IL-2 in the serum of beef cattle fed with fermented HTR increased significantly, which indicated that fermented HTR could enhance the immune function of beef cattle under heat stress.

The content of MDA indirectly reflects the degree of lipid peroxidation in tissues and cells, and can be used as a surrogate for the degree of cell damage [48]. SOD is an antioxidant enzyme that can scavenge free radicals in vivo. Studies show that heat stress can inhibit the expression of SOD [49]. T-AOC represents the antioxidant capacity of the whole body. In this study, the MDA level gradually decreased with the increase in fermented HTR, indicating that HTR could alleviate the cell damage caused by heat stress. SOD and T-AOC levels increased significantly in the 30% and 15% substitution groups, reflecting the antioxidant activity of fermented HTR, which was consistent with Chaudhary's findings [41].

In addition, some studies have suggested that to adapt to heat stress, the body needs to increase the absorption of glucose to ensure the energy supply, resulting in an increased serum glucose content [50]. In the present study, there was no significant difference in the total cholesterol level with increasing fermented HTR. However, under heat stress, the glucose level of the fattening cattle fed with the basal diet was significantly higher than that of cattle fed with the 30% fermented HTR alternative diet, suggesting that heat stress has an effect on the glucose level, which can be alleviated by fermented HTR. Compared with those of the CN group, the total protein and albumin of the fermented HTR groups increased and blood urea nitrogen decreased, which was consistent with Guo's results. Guo pointed out that this might be the result of thyroid regulation, which was conducive to maintaining the body's water and salt balance, and alleviating the adverse effects of heat stress [51].

At present, there are few studies on the effect of HTR on the fecal microorganisms of fattening cattle under heat stress. Recently, a study showed that there are significant differences in the microbial composition between spring and summer, indicating that environmental temperature has an impact on the microbial community structure of feces [52]. In the present study, we found that 30% fermented HTR had a more significant effect on heat stress index of fattening cattle than 15%; therefore, we chose the CN and HC group to study the fecal microbial community of fattening cattle. According to the results of alpha diversity analysis and PCA, the fecal microbial community of heat stressed fattening cattle fed with fermented HTR was significantly different from cattle fed with the basic diet, and the microbial diversity of the HC group increased. The most abundant bacteria in the phylum level of the CN and HC group were Firmicutes and Bacteroidetes. Li showed that under the different climates in spring and summer, the main microorganisms in cow feces were Firmicutes and Bacteroidetes; in summer, Firmicutes levels were higher than those in spring, while Bacteroidetes levels were lower than those in spring [52]. It has been reported that ruminants have a core microbial community mainly composed of Firmicutes and Bacteroidetes, which can maintain stable digestive function [53]. In our study, the feeding of fermented HTR changed the relative proportion of these two bacteria, which was consistent with Hu's study [54]. The results showed that the enrichment of Firmicutes in the HC group was significantly higher than that in CN group, and Bacteroidetes levels in HC group were significantly lower, indicating that fermented HTR had a certain effect on fecal microbial flora of fattening cattle under summer heat stress. It is reported that Bacteroidetes is mainly responsible for the degradation of fiber, and its degree of enrichment is related to diets with a high fiber content. By contrast, Firmicutes are responsible for the degradation of carbohydrates, fats, and proteins, which are related to a high calorie diet [55]. We inferred that the total fiber content of the diet replaced by fermented HTR decreased.

At the family taxonomic level, the Rikenellaceae and Paludibacteraceae in the HC group decreased, and the Ruminococcaceae increased. It has been reported that the Rikenellaceae increased and the Ruminococcaceae decreased in the intestines of mice fed with a high-fat diet, suggesting that a high calorie diet can cause changes in the intestinal microflora [56], which is contrary to the results of the HC group and might be explained by the fact that under heat stress, the fermented HTRs reduced the caloric level of the diet, alleviated the heat production during fattening, and changed the intestinal flora. At the genus taxonomic level, Fournierella and Oscillibacter are two genera of the Ruminocaceae, and both showed an increasing trend in the HC group. Acetobacterium, Anaerovorax, Butyrivibrio, and Erysipelotrichaceae also increased in the HC group. A study has reported that Butyrivibrio is more involved in epithelium promotion, while Erysipelotrichaceae is more abundant at high temperatures [57]. Besides, Alistipes decreased in the HC group. A study suggested that Alistipes is the source of colorectal cancer, and its abundance is related to the severity of intestinal diseases [58], which indicates that fermented HTR is beneficial to maintain the health of fattening cattle under heat stress.

We also studied the association between fecal SCFAs and microorganisms at the genus level where changes were observed. We found that there was a significant positive correlation between Aa and the relative abundance of Acetobacterium and a positive correlation between Pa and the relative abundance of Acetobacterium, Erysipelotrichaceae, and Fournierella. It has been reported that Acetobacter is mainly involved in Aa fermentation [59] and Fournierella can metabolize and produce Aa and Pa [60]. SCFAs are the main products of microbial metabolism in the intestines, and the types and quantity of SCFAs are regulated by microbial species, diet, and the environment [24]. Therefore, we speculated that fermented HTRs change the composition and abundance of large intestine microorganisms in fattening cattle, promote the fermentation of large intestine microorganisms, and help the body to maintain health and resist the adverse effects of heat stress.

After fermentation with oat grass and compound bacteria, the water content of the HTR decreased and the nutritional level increased, which was conducive to the resource utilization of HTR. In addition, fermented HTR could alleviate the heat stress of fattening cattle in summer, improve their growth performance, enhance their immune performance, help them to resist an adverse environment, and maintain their health. In addition, 30% fermented HTR replacement had an impact on the fecal microbial community of heat stressed fattening cattle, and the bacteria were closely related to the cattle’s fecal SCFA levels. Based on our findings, we concluded that 30% fermented HTRs replacing Pennisetum purpureum might be advantageous for fattening cattle under heat stress. In addition, the co-fermented products also included molasses, oat hay, and mixed bacterial strains in our test, and the potential roles of these co-fermented products on heat stress should be further study.

5.1. Fermentation

The HTRs used in the experiment were obtained from Heyuan Jilongxiang Biological Technology Co., LTD. (Heyuan, Guangdong, China). The molasses and strains were purchased from Guangzhou Linong Feed Co., LTD. (Guangzhou, Guangdong, China). The feedstock department of Guangzhou Fengxing Dairy Co., LTD. (Guangzhou, Guangdong, China) provided the oat hay.

In this experiment, fermentation was carried out on HTR and oat hay (CP: 12.3%; NDF: 50.8%; ADF: 26.7%) with a mass ratio of 6:4 on a wet weight basis, with 2% added molasses. The mixed bacteria used for fermentation were Sacconomyces ceratomyces GDMCC2.167, Bacillus subcultivar GDMCC1.372, Lactobacillus plantarum GIM1.191, and Enterococcus faecalis GdMCC1.612, with mass ratios of 250g: 1t, 300g: 1t, 300g: 1t, and 200g: 1t, respectively. The fermentation materials were mixed and stirred evenly using a feed-stuff mixer, and then were packaged (50 Kg each), compacted, sealed, and fermented for 25–30 days at room temperature. After approximately 30 days of fermentation, 20 g of fermented samples were added to 180 mL of distilled water, sealed with preservative film, and placed in a refrigerator at 4 °C for 24 h. During extraction, the solution was shaken every 30 min. After 24 h, the solution was filtered through qualitative filter paper, and a pH meter (Horiba, Tokyo, Japan) was used to determine the pH value of the filtrate. High performance liquid chromatography (HPLC) was used to determine the content of organic acids in the extract of fermented HTRs, while AOAC International guidelines [61] were used to analyze the dry matter, crude protein, neutral detergent fiber, acid detergent fiber, and ash contents.

5.2. Experimental animals and design

This experiment was carried out in Guangzhou from July to August in 2019, and the weather is hot, rainy and humid, which usually leads to a natural heat stress and we judged whether the individuals were in the state of heat stress by using the environmental temperature and humidity index [23]. A total of 45 healthy female Simmental crossbred cattle, balanced with body weight, were selected and divided into three treatment groups: The CN group (fed with basic diet, without fermented HTR), the LC group (fermented HTR replaced 15% of Pennisetum purpureum), and the HC group (fermented HTR replaced 30% of Pennisetum purpureum). The experiment lasted for 40 days, including a 7-day adaptation period and a 33-day formal experimental period.

The animal feeding experiment was carried out at the Yunfu benben beef cattle farm (Yunfu, Guangdong, China), and the basic diet for the experimental cattle was provided by the farm and was shown in Table S1. During the experiment, all individuals were fed at 8:00 am and 5:00 pm every day. A total mixed ration (TMR) feed mixer was used to fully mix the experimental diets, and the diet and drinking water were allowed to intake freely during the experiment.

5.3. Measurements and sampling

During the experiment, a dry and wet thermometer (Kimo Industry Co., Biarritz, France) was set at 1.5 meters above the ground in the cowshed. The temperature, humidity, and wet bulb temperature of the cowshed were recorded at 08:00, 14:00, and 20:00 every day to calculate the daily average temperature, humidity and the temperature humidity index (THI) of the cowshed. The following formula was used to calculate the THI: THI = (0.35×TDB + 0.65×TWB)×1.8 + 32, where TDB is the dry bulb temperature and TWB is the wet bulb temperature [23].

An animal thermometer (Kruuse, Langeskov, Denmark) was used to measure the rectal temperature (RT) of the experimental cattle at 08:00, 14:00, and 22:00 every day, while respiratory rate (RR), measured as the number of flank movements per minute, was recorded. At the beginning and end of the formal experiment, the weights of the experimental cattle were recorded after a 12-hour overnight fast. The amount of TMR consumed by the experimental cattle, and that remaining unconsumed, were recorded every day. The above data were used to calculate the average daily feed intake (ADFI), average daily gain (ADG), and the feed to weight ratio (F/G). On the day before the end of the experiment, six individuals in each treatment group were randomly selected and 20 mL blood samples were taken from the tail vein, placed in a centrifuge tube, and then centrifuged immediately after being placed obliquely for 2h. Enzyme linked immunosorbent assay (ELISA) kits were used to determine the serum levels of heat shock protein 70 (HSP70), cortisol (Cor), lactate dehydrogenase (LDH), immunoglobulin G (IgG), immunoglobulin A (IgA), alanine aminotransferase (ALT), creatine kinase (CK), total antioxidant capacity (T-AOC), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) according to the manufacturer instrutions (Nanjing Jiancheng Bioengineering Research Institute, Nanjing, China).

At the end of the experiment, in each group 200 grams of feces of six fattening cattle were collected immediately after defecation, put into frozen storage tubes, and stored in liquid nitrogen. Approximately 100 grams were used for HPLC (Actlabs, Ancaster, ON, Canada) determination of fecal volatile fatty acid contents, including acetic acid (Aa), propionic acid (Pa), isobutyric acid (Ia), butyric acid (Ba), isovaleric acid (Iva), and valeric acid (Va). Total genomic DNA was extracted from the other 100 grams to investigate fecal microorganisms.

5.4. 16S rRNA gene sequencing and annotation analysis

We chose to amplify the V3 and V4 regions of the 16S rRNA sequence of the bovine fecal microbial communities, and then constructed gene fragment libraries. The paired end method was used to sequence the libraries on the Illumina Novaseq sequencing platform (Illumina, Waltham, MA, USA). High-quality tags data (clean tags) were obtained after splicing and filtering of the reads [62], and then mosaic filtering was performed to obtain effective tags for subsequent analysis. The Uparse software (Uparse v7.0.1001) [63] was used to cluster all effective tags of all samples. Sequences with ≥ 97% identity were clustered into same operational taxonomic units (OTUs). Then, Silva databases and Mothur [64] were used to annnotate and analyze the OUT sequences. The composition and abundance of microbial communities in each sample were counted at each taxonomic level, including kingdom, phylum, class, order, family, genus, and species. Fast multiple sequence alignment and annotation was carried out using the MUSCLE software (Version 3.8.31), and the phylogenetic relationships between different OTUs were obtained [65]. Finally, the data of each sample were homogenized, and the subsequent Alpha and Beta diversity were analyzed based on the homogenized data. The QIIME pipeline (Version 1.7.0) was used to calculate the UniFrac distance and an Unweighted Pair-group Method with Arithmetic Means (UPGMA) clustering tree was also constructed. The R software (Version 2.15.3) was used to draw Principal Component Analysis (PCA), Principal Co-ordinates Analysis (PCoA), and Non-Metric Multi-Dimensional Scaling (NMDS) maps to explore the differences of community structure among the different samples. The Linear discriminant analysis Effect Size (LEfSe) analysis was performed with a linear discriminant analysis LDA score of 2 to further analyze the differences in community structure.

5.5. Statistical analysis

One-way analysis of variance (ANOVA) and Duncan’s test (SPSS 17.0, IBM Corp., Armonk, NY, USA) were used to analyze the physiological parameters, serum biochemical indices, and the fecal concentrations of short-chain fatty acids (SCFAs). The results are shown as the mean ± standard error (SE), and P < 0.05 and P < 0.01 were used as the criteria to judge significant and extremely significant differences.

Authors’ contributions

XNZ and JJS conceived the report, participated in its design, performed data analysis, and drafted the manuscript; ZJC, XHS and FJL performed in experiments. JYL, TC, QYX and YLZ provided guidance and funding. All authors read and approved the final manuscript.

Funding

This work was supported by the Natural Science Foundation of China Program [grant numbers 31802032, 32072714]; the Natural Science Foundation of Guangdong Province [grant number 2020A1515010062]; the Science and Technology Project of Guangzhou [grant number 202002030037]; and the Key-Area Research and Development Program of Guangdong Province [2019B110209005].

Availability of data and materials

The raw sequences were deposited into Sequence Read Archive (SRA) database with the BioProject accession number PRJNA699165.

Ethics approval and consent to participate

The animal feeding experiment was carried out at the Yunfu benben beef cattle farm (Yunfu, Guangdong, China). The tested animals were housed in an open cowshed, and animals were fed individually. All animal procedures were approved by the owner of farm and the Animal Care Committee at South China Agricultural University according to the university’s guidelines for animal research (2018F006).

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Li FS, Weng JK. Demystifying traditional herbal medicine with modern approach. Nat Plants. 2017;3:17109.
Chio PH, Zaroff CM. Traditional Chinese medicinal herbal tea consumption, self-reported somatization, and alexithymia. Asia Pac Psychiatry. 2015;7(2):127-34.
Desideri D, Meli MA, Roselli C, Feduzi L. Alpha and gamma spectrometry for determination of natural and artificial radionuclides in tea, herbal tea and camomile marketed in italy. Microchem. J. 2011;98( 1):170-175.
Zhao J, Deng JW, Chen YW, Li SP. Advanced phytochemical analysis of herbal tea in China. J Chromatogr A. 2013;1313:2-23.
Dalar A, Konczak I. Phenolic contents, antioxidant capacities and inhibitory activities against key metabolic syndrome relevant enzymes of herbal teas from eastern anatolia. Ind. Crops Prod. 2013;44:383–390
Shen J, Shan J, Zhu X, Xu Y, Li M. Effect of Chinese Herbal Tea on Health Tested on Drosophila Model. Plant Foods Hum Nutr. 2020;75(2):305-306.
Yang D, Liang J, Wang Y, Sun F, Tao H, Xu Q, et al Tea waste: an effective and economic substrate for oyster mushroom cultivation. J Sci Food Agric. 2010;96(2):680-4.
Kondo M, Kita K, Yokota H. Effects of tea leaf waste of green tea, oolong tea, and black tea addition on sudangrass silage quality and in vitro gas production. J. Sci. Food Agric. 2004;84(7):721-727.
Ozdemir N, Yakupoglu T, Dengiz O. The effects of bio-solid and tea waste application into different levels of eroded soil on N, P and K concentrations. Environ Monit Assess. 2009;156(1-4):109-18.
Hameed BH. Spent tea leaves: a new non-conventional and low-cost adsorbent for removal of basic dye from aqueous solutions. J Hazard Mater. 2009;161(2-3):753-9.
Shang JG, Kong XR, He LL, Li WH, Liao QJH. Low-cost biochar derived from herbal residue: characterization and application for ciprofloxacin adsorption. Int. J. Environ. Sci. Technol. 2016;13(10):2449-2458.
Ahsan MA, Katla SK, Islam MT, Hernandez-Viezcas JA, Martinez LM, Díaz-Moreno CA, et al. Adsorptive removal of methylene blue, tetracycline and Cr (VI) from water using sulfonated tea waste. Environ. Technol. Innov. 2018;11:23-40.
Cheraghi M, Sobhanardakani S, Lorestani B, Zandipak R. Tea wastes efficiency on removal of cd(ii) from aqueous solutions. Arch. Hyg. Sci. 2016;5(3):184-191.
Dizadji N, Anaraki NA. Adsorption of chromium and copper in aqueous solutions using tea residue. Int. J. Environ. Sci. and Tech. 2011;8(3):631-638
Wan S, Qu N, He F, Wang M, Liu G, He H. Tea waste-supported hydrated manganese dioxide (hmo) for enhanced removal of typical toxic metal ions from water. RSC Advances. 2015;5:88900-88907.
Lunge S, Singh S, Sinha A. Magnetic iron oxide (fe3o4) nanoparticles from tea waste for arsenic removal. J. Magn. Magn. Mater. 2014;356:21-31.
Ramdani D, Chaudhry AS, Seal CJ. Chemical composition, plant secondary metabolites, and minerals of green and black teas and the effect of different tea-to-water ratios during their extraction on the composition of their spent leaves as potential additives for ruminants. J Agric Food Chem. 2013;61(20):4961-7.
Liu HW, Tong JM, Zhou, DW. Utilization of chinese herbal feed additives in animal production. Agric Sci China. 2011;10:1262-1272.
Samanta AK, Jayaram C, Jayapal N, Sondhi N, Kolte AP, Senani S, et al. Assessment of Fecal Microflora Changes in Pigs Supplemented with Herbal Residue and Prebiotic. PLoS One. 2015;10(7):e0132961.
Liu W, Rouzmehr F, Seidavi A. Effect of amount and duration of waste green tea powder on the growth performance, carcass characteristics, blood parameters, and lipid metabolites of growing broilers. Environ Sci Pollut Res Int. 2018;25(1):375-387.
Guven A, Nur G, Deveci HA. Effect of green tea (camellia sinensis l.) and parsley (petroselinum crispum) diets against carbon tetrachloride hepatotoxicity in albino mice. Int J Syst Evol Microbiol. 2019;28(9):6521-6527.
Xie Y, Chen Z, Wang D, Chen G, Sun X, He Q, et al. Effects of Fermented Herbal Tea Residues on the Intestinal Microbiota Characteristics of Holstein Heifers Under Heat Stress. Front Microbiol. 2020;11:1014.
Berman A. Estimates of heat stress relief needs for Holstein dairy cows. J Anim Sci. 2005;83(6):1377-84.
Macfarlane S, Macfarlane GT. Regulation of short-chain fatty acid production. Proc Nutr Soc. 2003;62(1):67-72.
Kondo M, Nakano M, Kaneko A, Agata H, Kita K, Yokota H. Ensiled green tea waste as partial replacement for soybean meal and alfalfa hay in lactating cows. Asian-Aust. J. Anim. Sci. 2004;17(7):960- 966.
Ding X, Li H, Wen Z, Hou Y, Wang G, Fan J, et al. Effects of Fermented Tea Residue on Fattening Performance, Meat Quality, Digestive Performance, Serum Antioxidant Capacity, and Intestinal Morphology in Fatteners. Animals (Basel). 2020;10:185.
Smith LH. Theoretical carbohydrate requirement for alfalfa silage production. Agron. J. 1962;54(4):291-293.
Thompson DN, Barnes JM, Houghton TP. Effect of additions on ensiling and microbial community of senesced wheat straw. Appl Biochem Biotechnol. 2005;121-124:21-46.
Chen KL, Kho WL, You SH, Yeh RH, Tang SW, Hsieh CW. Effects of Bacillus subtilis var. natto and Saccharomyces cerevisiae mixed fermented feed on the enhanced growth performance of broilers. Poult Sci. 2009;88(2):309-15.
Wang C, He L, Xing Y, Zhou W, Yang F, Chen X, et al. Fermentation quality and microbial community of alfalfa and stylo silage mixed with Moringa oleifera leaves. Bioresour Technol. 2019;284:240-247.
Hahn GL. Dynamic responses of cattle to thermal heat loads. J Anim Sci. 1999;77 Suppl 2:10-20.
St-Pierre NR, Cobanov B, Schnitkey G. Economic losses from heat stress by us livestock industries1. Jour Dairy Sci. 2003;86:52-77.
Belhadj Slimen I, Najar T, Ghram A, Abdrrabba M. Heat stress effects on livestock: molecular, cellular and metabolic aspects, a review. J Anim Physiol Anim Nutr (Berl). 2016;100(3):401-12.
Zhong S, Ding Y, Wang Y, Zhou G, Guo H, Chen Y, et al. Temperature and humidity index (THI)-induced rumen bacterial community changes in goats. Appl Microbiol Biotechnol. 2019;103(7):3193-3203.
da Costa AN, Feitosa JV, Montezuma PA Jr, de Souza PT, de Araújo AA. Rectal temperatures, respiratory rates, production, and reproduction performances of crossbred Girolando cows under heat stress in northeastern Brazil. Int J Biometeorol. 2015;59(11):1647-53.
Song X, Luo J, Fu D, Zhao X, Bunlue K, Xu Z, et al. Traditional chinese medicine prescriptions enhance growth performance of heat stressed beef cattle by relieving heat stress responses and increasing apparent nutrient digestibility. Asian-Australas J Anim Sci. 2014;27(10):1513-20.
Chen J, Guo K, Song X, Lan L, Liu S, Hu R, et al. The anti-heat stress effects of Chinese herbal medicine prescriptions and rumen-protected γ-aminobutyric acid on growth performance, apparent nutrient digestibility, and health status in beef cattle. Anim Sci J. 2020;91(1):e13361.
Wang J, Li J, Wang F, Xiao J, Wang Y, Yang H, et al. Heat stress on calves and heifers: a review. J Anim Sci Biotechnol. 2020;11:79.
Chanclón B, Martínez-Fuentes AJ, Gracia-Navarro F. Role of SST, CORT and ghrelin and its receptors at the endocrine pancreas. Front Endocrinol (Lausanne). 2012;3:114.
Hocking PM, Maxwell MH, Mitchell MA. Haematology and blood composition at two ambient temperatures in genetically fat and lean adult broiler breeder females fed ad libitum or restricted throughout life. Br Poult Sci. 1994;35(5):799-807.
Chaudhary SS, Singh VK, Upadhyay RC, Puri G, Odedara AB, Patel PA. Evaluation of physiological and biochemical responses in different seasons in Surti buffaloes. Vet World. 2015;8(6):727-31.
Weitzel JM, Viergutz T, Albrecht D, Bruckmaier R, Schmicke M, Tuchscherer A, et al. Hepatic thyroid signaling of heat-stressed late pregnant and early lactating cows. J Endocrinol. 2017;234(2):129-141.
Dahl GE, Tao S, Laporta J. Heat Stress Impacts Immune Status in Cows Across the Life Cycle. Front Vet Sci. 2020;7:116.
Liu DY, He SJ, Liu SQ, Tang YG, Jin EH, Chen HL, et al. Daidzein enhances immune function in late lactation cows under heat stress. Anim Sci J. 2014;85(1):85-9.
Padgett DA, Glaser R. How stress influences the immune response. Trends Immunol. 2003;24(8):444-8.
Esposito G, Irons PC, Webb EC, Chapwanya A. Interactions between negative energy balance, metabolic diseases, uterine health and immune response in transition dairy cows. Anim Reprod Sci. 2014;144(3-4):60-71.
Costa LB, Luciano FB, Miyada VS, Gois FD. Herbal extracts and organic acids as natural feed additives in pig diets. S Afr J Anim Sci. 2013;43:181–93.
Tsikas D. Assessment of lipid peroxidation by measuring malondialdehyde (MDA) and relatives in biological samples: Analytical and biological challenges. Anal Biochem. 2017;524:13-30.
Yang CY, Lin MT. Oxidative stress in rats with heatstroke-induced cerebral ischemia. Stroke. 2002;33(3):790-4.
Sun X, Zhang H, Sheikhahmadi A, Wang Y, Jiao H, Lin H, et al. Effects of heat stress on the gene expression of nutrient transporters in the jejunum of broiler chickens (Gallus gallus domesticus). Int J Biometeorol. 2015;59(2):127-35.
Guo K, Cao H, Zhu Y, Wang T, Hu G, Kornmatitsuk B, et al. Improving effects of dietary rumen protected γ-aminobutyric acid additive on apparent nutrient digestibility, growth performance and health status in heat-stressed beef cattle. Anim Sci J. 2018;89(9):1280-1286.
Li H, Li R, Chen H, Gao J, Wang Y, Zhang Y, et al. Effect of different seasons (spring vs summer) on the microbiota diversity in the feces of dairy cows. Int J Biometeorol. 2020;64(3):345-354.
Weimer PJ. Redundancy, resilience, and host specificity of the ruminal microbiota: implications for engineering improved ruminal fermentations. Front Microbiol. 2015;6:296.
Hu X, Liu G, Li Y, Wei Y, Lin S, Liu S, et al. High-Throughput Analysis Reveals Seasonal Variation of the Gut Microbiota Composition Within Forest Musk Deer (Moschus berezovskii). Front Microbiol. 2018;9:1674.
Jami E, Israel A, Kotser A, Mizrahi I. Exploring the bovine rumen bacterial community from birth to adulthood. ISME J. 2013;7(6):1069-79.
Daniel H, Gholami AM, Berry D, Desmarchelier C, Hahne H, Loh G, et al. High-fat diet alters gut microbiota physiology in mice. ISME J. 2014;8(2):295-308.
Ziętak M, Kovatcheva-Datchary P, Markiewicz LH, Ståhlman M, Kozak LP, Bäckhed F. Altered Microbiota Contributes to Reduced Diet-Induced Obesity upon Cold Exposure. Cell Metab. 2016;23(6):1216-1223.
Parker BJ, Wearsch PA, Veloo ACM, Rodriguez-Palacios A. The Genus Alistipes: Gut Bacteria With Emerging Implications to Inflammation, Cancer, and Mental Health. Front Immunol. 2020;11:906.
Kremp F, Poehlein A, Daniel R, Müller V. Methanol metabolism in the acetogenic bacterium Acetobacterium woodii. Environ Microbiol. 2018;20(12):4369-4384.
Togo AH, Durand G, Khelaifia S, Armstrong N, Robert C, Cadoret F, et al. Fournierella massiliensis gen. nov., sp. nov., a new human-associated member of the family Ruminococcaceae. Int J Syst Evol Microbiol. 2017;67(5):1393-1399.
Horwitz W. Official methods of analysis of AOAC International. Volume I, agricultural chemicals, contaminants, drugs/edited by William Horwitz. Gaithersburg (Maryland): AOAC International. 2020.
Bokulich NA, Subramanian S, Faith JJ, Gevers D, Gordon JI, Knight R, et al. Quality-filtering vastly improves diversity estimates from Illumina amplicon sequencing. Nat Methods. 2013;10(1):57-9.
Edgar RC. UPARSE: highly accurate OTU sequences from microbial amplicon reads. Nat Methods. 2013 Oct;10(10):996-8.
Quast C, Pruesse E, Yilmaz P, Gerken J, Schweer T, Yarza P, et al. The SILVA ribosomal RNA gene database project: improved data processing and web-based tools. Nucleic Acids Res. 2013;41(Database issue):D590-6.
Edgar RC. MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Res. 2004;32(5):1792-7.

Table 1 Nutrient composition of fermented herbal tea residue for 0 and 30 days
Item	Fermentation for 0 days	Fermentation for 30 days
PH	4.95 ± 0.03	3.89 ± 0.04
Dry matter (%)	26.58 ± 0.74	24.94 ± 0.51
Crude protein (%)	8.85 ± 0.98	9.92 ± 0.82
Ash (%)	6.17 ± 0.04	6.56 ± 0.06
Neutral detergent fiber (%)	60.11 ± 1.30	54.29 ± 0.86
Acid detergent fiber (%)	34.33 ± 0.28	30.01 ± 0.36
Acetic acid (mmol/g)	17.293 ± 0.24	115.405 ± 0.95
Propionic acid (mmol/g)	0.306 ± 0.06	8.382 ± 0.13
Lactic acid (mmol/g)	174.78 ± 0.02	1247.01 ± 0.04
Note: The values were calculated as the means ± standard error of the mean (N = 6), except for dry matter, others item are based on dry matter.

No competing interests reported.

Supplementarymaterial.rar

Download PDF

Journal Publication

published 12 Nov, 2021

Read the published version in BMC Veterinary Research →

Editorial decision: Major revision
13 Oct, 2021
Reviews received at journal
28 Sep, 2021
Reviewers agreed at journal
28 Sep, 2021
Reviewers invited by journal
28 Sep, 2021
Editor assigned by journal
28 Sep, 2021
Editor invited by journal
28 Sep, 2021
Submission checks completed at journal
28 Sep, 2021
First submitted to journal
27 Aug, 2021

You are reading this latest preprint version

Fermentation Quality of Herbal Tea Residue and its Application in Fattening Cattle Under Heat Stress

Status:

Journal Publication

Version 1

Abstract

Figures

1. Introduction

2. Result

2.1. Nutritional components and changes to the HTR after fermentation

2.2. Temperature and humidity index in the cowshed

2.3. Effects of fermented HTR on RR and RT of fattening cattle under heat stress

2.4 Effects of fermented HTR on feed intake and weight gain

2.5 Effects of fermented HTR on serum biochemical indexes

2.6. 16S rRNA gene sequencing and annotation analysis

2.7. Fecal SCFAs concentration and their correlation with microbiota genera

3. Discussion

4. Conclusion

5. Materials And Methods

5.1. Fermentation

5.2. Experimental animals and design

5.3. Measurements and sampling

5.4. 16S rRNA gene sequencing and annotation analysis

5.5. Statistical analysis

Declarations

References

Tables

Additional Declarations

Supplementary Files

Status:

Journal Publication

Version 1