In Table 3, compared to the CK group, the crease heights of PI, MI and DI were eminently lower in the Gly and SB1 groups (P < 0.05); the crease widths of PI, MI and DI were eminently lower in the Gly group and the crease widths of MI and DI in the SB2 and SB4 groups (P < 0.05); the lamina propria thicknesses of PI, MI and DI were eminently lower in the Gly group and the lamina propria thicknesses of PI and DI in the SB1 group (P < 0.05); the Gly and SB4 groups had eminently higher lamina propria widths. Compared to the Gly group, the crease heights of PI, MI and DI were eminently higher in the SB3 and SB4 groups (P < 0.05); the crease widths of DI and the sarcomere thicknesses of PI, MI and DI were significantly higher in the SB2 and SB3 groups (P < 0.05); and the intrinsic layer widths of MI and DI were eminently lower in the SB3 group (P < 0.05).
Table 3
Effect of sodium butyrate on morphological indicators of the intestinal tract of common carp fed glycinin.
Indexes | Group |
CK | Gly | SB1 | SB2 | SB3 | SB4 |
Intestinal somatic index (%) | 2.61 ± 0.34 | 2.28 ± 0.2a | 2.59 ± 0.41a | 2.25 ± 0.19a | 2.78 ± 0.19a | 2.32 ± 0.17a |
Intestinal length index (%) | 1.73 ± 0.12 | 1.58 ± 0.04a | 1.66 ± 0.2a | 1.69 ± 0.26a | 1.83 ± 0.23a | 1.51 ± 0.14a |
PI fold height (µm) | 358.61 ± 17.54 | 288.35 ± 15.34c** | 301.51 ± 13.79bc* | 333.11 ± 13.13ab | 346.46 ± 11.85a | 324.16 ± 11.13ab* |
MI fold height (µm) | 285.22 ± 12.17 | 211.42 ± 11.82c** | 223.98 ± 11.91bc* | 254.39 ± 11.81ab* | 271.77 ± 7.32a | 242.15 ± 12.88ab* |
DI fold height (µm) | 242.49 ± 20.54 | 152.91 ± 18.79c** | 166.2 ± 11.2bc** | 198.73 ± 10.94bc* | 233.08 ± 14.43a | 214.41 ± 12.19a |
PI fold width (µm) | 136.58 ± 9.56 | 113.46 ± 8.02a* | 121.91 ± 10.21a | 126.07 ± 7.6a | 133.1 ± 10.16a | 124.76 ± 11.81a |
MI fold width (µm) | 110.65 ± 4.2 | 80.54 ± 5.36a** | 91.12 ± 7.83ab* | 102.16 ± 5.88a | 104.98 ± 8.5a | 94.27 ± 5.27ab* |
DI fold width (µm) | 106.03 ± 6.83 | 75.69 ± 7.27b** | 87.08 ± 6.66ab* | 97.45 ± 5.51a | 101.83 ± 8.67a | 92.12 ± 2.98ab* |
PI muscular layer thickness (µm) | 33.36 ± 3.57 | 20.27 ± 2.91b** | 26.01 ± 1.89ab* | 28.89 ± 2.32a | 32.15 ± 3.21a | 28.11 ± 1.77a |
MI muscular layer thickness (µm) | 25.15 ± 1.99 | 16.08 ± 1.69b** | 20.53 ± 2.13ab | 22.4 ± 0.68a | 25.17 ± 2.71a | 20.64 ± 1.56ab* |
DI muscular layer thickness (µm) | 25.68 ± 2.53 | 13.54 ± 1.55c** | 17.2 ± 1.93bc* | 20.47 ± 0.67ab* | 23.13 ± 1.46a | 18.78 ± 2.55ab* |
PI lamina propria width (µm) | 19.51 ± 1.99 | 20.62 ± 2.07a | 21.22 ± 0.77a | 18.56 ± 0.94a | 22.28 ± 1.98a | 23.24 ± 3.49a |
MI lamina propria width (µm) | 20.22 ± 1.78 | 26.61 ± 2.65a* | 23.78 ± 2.78ab | 21.34 ± 1.31ab | 19.01 ± 1.31b | 24.88 ± 1.59a* |
DI lamina propria width (µm) | 20.14 ± 5.44 | 41.43 ± 5.71a* | 34.34 ± 4.31ab* | 27.54 ± 1.84b | 25.21 ± 4.26b | 33.13 ± 3.19ab* |
A, proximal intestine; B, mid intestine; C, distal intestine. |
Dissimilar letters show significant difference (P < 0.05) among the Gly, SB1, SB2, SB3 and SB4 groups. Asterisk (*) represents a significant difference of P < 0.05 between the treatment and the control. Double asterisks (**) represent a significant difference of P < 0.01 between the treatment and the control. |
In Fig. 1, the serotonin, endothelin, D-lactic acid content and diamine oxidase activities in the common carp serum of the Gly group were eminently higher than in the CK group (P < 0.05). The contents of serotonin and D-lactic acid in the serum of the SB3 group were not eminently different from the CK group (P > 0.05). In addition, serum endothelin, D-lactic acid content and diamine oxidase activities in SB2, SB3 and SB4 groups were eminently lower than in the Gly group (P < 0.05). The serotonin in serum of SB3 group was also eminently lower than the Gly group (P < 0.05).
In Fig. 2, the ERK expressions in MI, DI and hepatopancreatic of the Gly group were eminently higher than in the CK group (P < 0.05), but there was no eminent difference in PI (P > 0.05). There was no eminent difference in the ERK expression in MI between the SB2 group and the CK group (P > 0.05). There was no eminent difference in the ERK expression in DI between the SB3 group and the CK group (P > 0.05). The ERK expression in the hepatopancreas of the SB2 and SB3 groups was eminently lower than in the CK group (P < 0.05). The expression levels of ERK in the MI, DI and hepatopancreas in SB2, SB3 and SB4 groups were eminently lower than in the Gly group (P < 0.05).
In Fig. 3, there was no eminent difference in the JNK expression in the PI (P > 0.05). The JNK expression in the MI, DI and hepatopancreas of the Gly group was eminently higher than in the CK group (P < 0.05). The JNK expression in the MI and DI of the SB3 group was not eminently different from the CK group (P > 0.05). The JNK expression in the MI, DI and hepatopancreas of SB2 and SB3 groups was eminently lower than in the Gly group (P < 0.05).
In Fig. 4, the expression of P38 in the MI and DI of the Gly group was eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI and hepatopancreas (P > 0.05). The expression of P38 of SB3 in PI, MI and hepatopancreas was eminently lower than in the CK group (P < 0.05), but there was no eminent difference in the expression levels in DI compared with the CK group (P > 0.05). The expression of P38 in SB2, SB3 and SB4 was eminently higher in MI, DI and hepatopancreas than in the Gly group (P < 0.05).
In Fig. 5, the Fasl expression in the MI, DI and hepatopancreas of the Gly group was eminently higher than that of the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). Fasl expression of SB2 in the DI and hepatopancreas was eminently lower than that in the CK group (P < 0.05), but there was no eminent difference in the MI (P > 0.05). There was no eminent difference in the expression of Fasl in the DI between the SB3 and SB4 groups and the control group (P > 0.05). The Fasl expression of the SB3 group in the hepatopancreas was eminently lower than that in the CK group (P < 0.05), while there was no eminent difference between the SB4 group and the CK group (P > 0.05). The expression of Fasl in DI and hepatopancreas of SB2, SB3 and SB4 groups was eminently lower than that of the Gly group (P < 0.05).
In Fig. 6, the Bcl-2 expression in the MI, DI and hepatopancreas of the Gly group was eminently lower than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). The Bcl-2 expression in the DI of the SB2 group was eminently higher than in the CK group and the Gly group (P < 0.05). The Bcl-2 expression in the MI, DI and hepatopancreas of the SB3 group was eminently higher than the CK group and the Gly group (P < 0.05). The Bcl-2 expression of SB4 in hepatopancreas was eminently higher than the CK group and Gly group (P < 0.05).
In Fig. 7, the Caspase-3 expression in the MI, DI and hepatopancreas of the Gly group was eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). The Caspase-3 expression in the MI of the SB2 group was eminently lower than that of the CK group (P < 0.05), and the Caspase-3 expression in the PI, MI, DI and hepatopancreas of the other groups was not eminently different from the CK group (P > 0.05). The Caspase-3 expression in the DI and hepatopancreas of the SB treatment group was eminently lower than in the Gly group (P < 0.05). The Caspase-3 expression in the MI of the SB2, SB3 and SB4 groups was eminently lower than in the Gly group (P > 0.05).
In Fig. 8, the Caspase-8 expression in the MI, DI and hepatopancreas of the Gly group was eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). The Caspase-8 expression in the DI of the SB treatment groups was eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the Caspase-8 expression in MI between the SB1, and SB2 groups and the CK group (P > 0.05). The Caspase-8 expression in the hepatopancreas of SB1, SB2 and SB3 groups was not eminently different from the CK group (P > 0.05). The Caspase-8 expression in PI of SB1, SB2 and SB3 groups was not eminently different from the Gly group (P > 0.05), but the Caspase-8 expression in MI, DI and hepatopancreas was eminently lower than Gly group (P < 0.05).
In Fig. 9, the Caspase-9 expression in the MI, DI and hepatopancreas of the Gly group were eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the Caspase-9 expression in the PI of the SB treatment groups (P > 0.05). The Caspase-9 expression in the MI and DI of the SB1, SB2 and SB3 groups was not eminently different from that of the CK group (P > 0.05). The Caspase-9 expression in the hepatopancreas of the SB3 group was eminently lower than in the CK group (P < 0.05). The Caspase-9 expression in the MI, DI and hepatopancreas of SB2, SB3 and SB4 groups were eminently lower than in the Gly group (P < 0.05).
In Fig. 10, the Fas expression in the MI, DI and hepatopancreas of the Gly group was eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the Fas expression in the PI in the SB treatment groups (P > 0.05). The Fas expression in the MI of the SB3 group was eminently lower than that of the CK group (P < 0.05). The Fas expression in the DI of the SB2 group was eminently lower than the CK group (P < 0.05). The Fas expression in the hepatopancreas of SB2, SB3 and SB4 groups was not eminently different from the CK group (P > 0.05). The Fas expression in the MI, DI and hepatopancreas of SB2, SB3 and SB4 groups was eminently lower than in the Gly group (P < 0.05).
In Fig. 11, the Bax expression in the MI, DI and hepatopancreas of the Gly group was eminently higher than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the Bax expression in the PI in the SB treatment groups (P > 0.05). There was no effect on the Bax expression in the MI between the SB4 group and the CK group, and there was no eminent difference in the Bax expression in the DI and hepatopancreas between the SB2 and SB3 groups and the CK group (P > 0.05). The Bax expression in the MI of the SB3 and SB4 groups was eminently lower than the Gly group, and the Bax expression in the DI and hepatopancreas of the SB2, SB3 and SB4 groups was eminently lower than the Gly group (P < 0.05).
In Fig. 12, the Occludin1 expression in the Gly group was eminently lower in the MI and DI than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the Occludin1 expression in the PI of the SB treatment groups (P > 0.05). The Occludin1 expression in the MI and DI of SB2 and SB3 groups was eminently higher than CK and Gly groups (P < 0.05).
In Fig. 13, the Claudin3 expression in the MI and DI of the Gly group was eminently lower than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). The Claudin3 expression in the PI of the SB3 group was eminently higher than the CK group P < 0.05). The Claudin3 expression in the MI and DI of the SB2 and SB3 groups was also eminently higher than in the CK group P < 0.05). The Claudin3 expression in the MI of the SB2 group was eminently higher than in the Gly group P < 0.05), and the Claudin3 expression in the DI of the SB2 and SB3 groups was also eminently higher than in the Gly group P < 0.05).
In Fig. 14, the Claudin7 expression in the MI and DI of the Gly group was eminently lower than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the Claudin7 expression in the PI of the SB treatment groups (P > 0.05). The Claudin7 expression in the MI of SB1, SB2 and SB3 groups was not eminently different from the CK group (P > 0.05). The Claudin7 expression in the DI of the SB3 group was eminently higher than the CK group (P < 0.05). The Claudin7 expression in the MI of the SB1 group was eminently higher than in the Gly group (P < 0.05). The Claudin7 expression in the DI of the SB2 and SB3 groups were also eminently higher than in the Gly group (P < 0.05).
In Fig. 15, the ZO-1 expression in the MI and DI of the Gly group was eminently lower than in the CK group (P < 0.05), but there was no eminent difference in the PI (P > 0.05). There was no eminent difference in the ZO-1 expression in the PI of the SB treatment groups (P > 0.05). The ZO-1 expression in the MI and DI of the SB2, SB3 and SB4 groups was eminently higher than in the CK group (P < 0.05). The ZO-1 expression in the MI and DI of the SB2 and SB3 groups were also eminently higher than in the Gly group (P < 0.05).
In Fig. 16, the PI, MI, and DI of the CK group were clear and complete, the intestinal villi were well developed, the striatum was neatly arranged, and the muscle layer was thicker, and the serosa was intact. In the Gly group, the intestinal mucosa of Gly group had different degrees of damage, and the PI, MI, and DI had eminently widened lamina propria, atrophy of the villi, and disruption of the intestinal structural integrity. The dietary SB groups repaired the intestinal mucosal damage caused by glycinin to a certain extent, decreased the width of the lamina propria, and increased the height of the intestinal villi.
In Fig. 17, the abundances of Clostridium and Bacteroidetes in the Gly group and the SB treatment groups were lower than the CK group, while the abundance of Proteobacteria was higher than the control group. This indicated that dietary glycinin altered the species abundance of common carp intestinal flora. In addition, the abundance of Proteobacteria in the dietary SB treatment groups was lower than the Gly group, while the abundance of Acidobacteria, Firmicutes and other species was higher than the Gly group. This suggests that SB can modulate the changes in intestinal flora species abundance induced by dietary glycinin in common carp.
In Fig. 18, the Gly group eminently changed the abundance of intestinal bacterial genera, among which Gemmobacter, Rhizobacteraceae and Rhodobacteraceae became the dominant genera. In the dietary SB group, Gammaproteobacteria, Chlamydiales, Gemmobacter, Arenimonas and Rhodobacteraceae became the dominant genera.
In Fig. 19, the genus Cetobacterium in the CK group had a higher abundance, while the genus Pseudoxanthomonas in the Gly group was higher. In the dietary SB group, Bosea and uncultured bacterium o Rhizobiales in the SB2 group, and the SB1 group The genus of uncultured bacterium f Rhizobiales Incertae Sedis in the SB3 group was higher, and the genus of uncultured bacterium o Chlamydiales in SB3 group was higher. In the SB4 group, the abundance of Defluviimonas was higher.
In Fig. 20, the dilution curves between each group tend to be flat, indicating that the number of OTO values between each group has met the requirements.
In Fig. 21, the OTO shared by each group is 782, and only group SB1 and SB4 have unique OTO.
In Fig. 22, Principal Coordinates Analysis (PCoA) also indicated that there were changes in the structure of the intestine microflora between groups. These results indicated that there were structural differences in beta diversity between the CK, glycinin, and dietary SB groups.