3.1 Performance and Carcass Characteristics
Table 2 displays the performance and carcass characteristics of the BKF4 hybrid resulting from molecular selection for high reproductive traits and hybrid breeding practices. BKF4 exhibited notable improvements in lambing rate and average daily gain at 3 months compared to the GB and SK groups (P ≤ 0.001). Additionally, BKF4 showed a significant increase in slaughter rate (P ≤ 0.05). Notably, BKF4 demonstrated a lambing rate increase of over 45.5% and more than doubled the average daily gain at 3 months compared to the purebred Guizhou Black Goat (GB). Moreover, BKF4 maintained the exceptional survival rate exceeding 95%, indicative of robust disease resistance. The hybrid also achieved a more than 7.6% increase in adult weight gain.
Table 2
Effects of Cross-Breeding on Performance and Carcass Characteristics of Goats
Items | GB | SK | BKF4 | P-value | Notes |
Lambing Percentage (LP, %) | 150.0 ± 10.6C | 170.0 ± 32.0B | 196.0 ± 16.35A | ≤ 0.001 *** | ≧ 45.5 |
Rate of Survival (SR, %) | 95.6 ± 2.5 | 87.0 ± 2.0 | 95.5 ± 2.5 | 0.127 | 0 |
Daily weight gain at 3 months of age (DWG, g) | 123.0 ± 25.0B | 280.0 ± 28.2 A | 275.5 ± 21.4A | ≤ 0.001 *** | ≧ 152 |
Adult Body Weight (ABW, kg ) | 48.0 ± 7.5 | 65.3 ± 8.0 | 55.6 ± 7.4 | 0.109 | ≧ 7.6 |
Dressing Percentage (DP, %) | 40.5 ± 2.5b | 60.0 ± 5.0a | 53.5 ± 3.3a | 0.038 * | ≧ 13.5 |
3.2 Meat Quality Indices
Trade-offs between intramuscular fat (IMF) and Other Chemical Components in the Cross-breeding System. Chemical analyses of IMF, pH45-value, drip loss, moisture content, ash and protein of longissimus dorsi were made before meat quality evaluation. The IMF content in BKF4 increased by 44% compared to GB (3.05 g/100g, P ≤ 0.001) and decreased by 30% compared to SK (6.08 g, P ≤ 0.01) (Table 3). However, the DL, MC and Ash significantly decreased (P ≤ 0.001) and pH45-value increased in BKF4 (P ≤ 0.001). However, DL, MC, and ash content significantly decreased (P ≤ 0.001), while pH45 significantly increased in BKF4 (P ≤ 0.001). The high fat and low water characteristics of BKF4 may suggest improved quality.
Table 3
Effect of Cross-breeding on Meat Quality Indices of Goats
Items | GB | SK | BKF4 | P - value |
pH45-value | 5.47 ± 0.16C | 6.18 ± 0.37B | 6.46 ± 0.17A | ≤ 0.001 *** |
Drip Loss (DL, %) | 4.47 ± 2.34A | 3.60 ± 1.58A | 1.49 ± 0.37B | ≤ 0.001 *** |
Moisture Content (MC, %) | 74.65 ± 0.94B | 76.99 ± 2.84A | 73.40 ± 1.09B | ≤ 0.001 *** |
Ash content (Ash, %) | 5.01 ± 1.03A | 4.29 ± 0.57B | 3.65 ± 0.00B | ≤ 0.001 *** |
Crude Protein content (CP, %) | 20.33 ± 0.60B | 19.21 ± 1.11C | 21.5 ± 0.58A | ≤ 0.001 *** |
Intramuscular Fat (IMF, %) | 3.05 ± 0.59B | 6.08 ± 2.46A | 4.40 ± 1.23B | ≤ 0.001 *** |
3.3 Amino Acid Composition
Table 4 outlines the analysis of 16 amino acids in the samples, including 7 essential amino acids (EAAs), 4 conditionally essential amino acids (CEAAs), 5 non-essential amino acids (NEAAs), and 9 pharmacologically relevant amino acids(PAAs). PC, EAAs, CEAAs, PAAs, PAAs/TAAs, EAAs/NC, and EAAI, SRC, NI, BV in GB and BKF4 were extremely significantly higher than in SK (P ≤ 0.01), and BCAAs, TAAs was significantly higher (P ≤ 0.05). Additionally, lysine, methionine, valine, phenylalanine, glycine, and proline levels in GB and BKF4 were extremely significantly higher than those in SK (P ≤ 0.01), while threonine, arginine, and alanine were significantly higher (P ≤ 0.05). Conversely, histidine was significantly lower in GB and BKF4 compared to SK (P ≤ 0.01), and serine was significantly lower (P ≤ 0.05). The amino acid profile of BKF4 closely resembled that of Guizhou Black Goat (GB). There were no significant differences in PER values among the three groups. In terms of taste intensity, GB and BKF4 showed extremely significantly higher values of (U + S + A)/B and aromatic flavor compared to SK (P ≤ 0.01), higher sweetness (P ≤ 0.05), and lower bitterness (P ≤ 0.05), with no significant difference in umami. The B:U:S:A profile indicated that BKF4 was more similar to GB.
Table 4
Effects of Cross-breeding on Amino Acid Composition in the Longissimus Dorsi of Goats
Items | GB | SK | BKF4 | P-value | |
Crude protein content (CP; expressed as g/100 g fresh LD tissue) | |
CP | 20.33 ± 0.60B | 19.21 ± 1.11C | 21.5 ± 0.58A | ≤ 0.001 *** | | | | |
Essential Amino Acids (EAA; expressed as g/100 g fresh LD tissue) | |
#Isoleucine | 3.78 ± 0.1 | 3.54 ± 0.29 | 3.68 ± 0.08 | 0.160 | |
#Leucine | 6.56 ± 0.19 | 6.16 ± 0.43 | 6.47 ± 0.16 | 0.141 | |
#Lysine | 6.82 ± 0.49 A | 2.56 ± 0.28 B | 7.06 ± 0.26 A | ≤ 0.001 *** | |
#Methionine | 2.29 ± 0.08 A | 1.71 ± 0.18 B | 2.1 ± 0.21 A | 0.002 ** | |
Threonine | 3.86 ± 0.12 a | 3.4 ± 0.24 b | 3.69 ± 0.15 a | 0.012 * | |
Valine | 4.19 ± 0.12 A | 3.6 ± 0.29 B | 3.96 ± 0.15 A | 0.004 ** | |
#Phenylalanine | 3.54 ± 0.09 A | 3.07 ± 0.2 B | 3.42 ± 0.18 A | 0.008 ** | |
Tryptophan | ND | ND | ND | | |
EAAs | 31.05 ± 1.02 A | 24.03 ± 1.88B | 30.37 ± 1.06 A | ≤ 0.001 *** | |
Conditionally essential amino acids (CEAA; expressed as g/100 g fresh LD tissue) | |
#Arginine | 5.14 ± 0.14a | 4.69 ± 0.35b | 5.12 ± 0.18a | 0.042 * | |
#Glycine | 4.48 ± 0.18 A | 3.33 ± 0.27 B | 4.57 ± 0.1A | ≤ 0.001 *** | |
Proline | 3.23 ± 0.08a | 2.81 ± 0.22b | 3.28 ± 0.23a | 0.015 ** | |
Tyrosine | 2.73 ± 0.07 | 2.61 ± 0.21 | 2.67 ± 0.05 | 0.422 | |
CEAAs | 15.58 ± 0.44 A | 13.43 ± 1.05 B | 15.63 ± 0.44 A | 0.002 ** | |
Non-essential amino acids (NEAA; expressed as g/100 g fresh LD tissue) | |
#Aspartic Acid | 7.2 ± 0.18 | 6.67 ± 0.46 | 6.96 ± 0.17 | 0.067 | |
#Glutamic acid | 12.54 ± 0.28 | 11.67 ± 0.77 | 12.62 ± 0.44 | 0.059 | |
Alanine | 4.61 ± 0.11a | 4.23 ± 0.33b | 4.66 ± 0.14a | 0.033 * | |
Serine | 2.46 ± 0.09b | 2.94 ± 0.19a | 2.6 ± 0.31b | 0.034 * | |
Histidine | 3.14 ± 0.1B | 6.4 ± 0.48 A | 2.34 ± 0.11C | ≤ 0.001 *** | |
NEAAs | 29.95 ± 0.69ab | 31.92 ± 2.23a | 29.18 ± 0.72b | 0.045 * | |
Partial sums (g/100 g of protein) | |
PAAs | 52.36 ± 1.5 A | 43.39 ± 3.2 B | 51.99 ± 1.53 A | ≤ 0.001 *** | |
TAAs | 76.58 ± 2.11a | 69.38 ± 5.16b | 75.19 ± 2.04a | 0.028 * | |
NC = NEAAs + CEAAs | 45.53 ± 1.12 | 45.35 ± 3.28 | 44.81 ± 1.05 | 0.838 | |
BCAAs | 14.54 ± 0.41 a | 13.29 ± 1.00 b | 14.1 ± 0.30 ab | 0.044 * | |
Ratios (%) | |
PAAs / TAAs | 68.37 ± 0.16 B | 62.54 ± 0.09C | 69.14 ± 0.21 A | ≤ 0.001 *** | |
EAAs / TAAs | 40.54 ± 0.29A | 34.63 ± 0.14 B | 40.39 ± 0.46 A | ≤ 0.001 *** | |
EAAs/ NC | 68.18 ± 0.83A | 52.98 ± 0.33 B | 67.77 ± 1.27 A | ≤ 0.001 *** | |
Nutritional Indices (%) | |
EAAI | 93.00 ± 0.03A | 72.00 ± 0.06 B | 90.25 ± 0.03 A | ≤ 0.001 *** | |
SRC | 80.96 ± 2.13 A | 73.54 ± 1.15C | 77.23 ± 1.13 B | ≤ 0.001 *** | |
NI | 18.93 ± 0.59 A | 13.87 ± 1.15 B | 19.38 ± 0.74 A | ≤ 0.001 *** | |
BV | 89.8 ± 3.15 A | 67.02 ± 6.52 B | 86.54 ± 3.73 A | ≤ 0.001 *** | |
PER | 2.22 ± 0.08 | 2.05 ± 0.17 | 2.19 ± 0.07 | 0.123 | |
Taste intensity | |
Umami | 4906.67 ± 113.36 | 4558 ± 307.38 | 4844.33 ± 135.62 | 0.069 | |
Bitterness | 556.94 ± 14.86 b | 666.46 ± 51.47 a | 551.13 ± 87.53 b | 0.047 * | |
Sweetness | 142.63 ± 3.87 a | 128.79 ± 9.77 b | 142.4 ± 4.78 a | 0.022 * | |
Aromatic flavor | 54.14 ± 1.43 A | 47.19 ± 3.17 B | 52.23 ± 2.51 A | 0.008 ** | |
Sweet and bitter | 201.34 ± 10.84A | 107.81 ± 9.37 B | 204.41 ± 8.48A | ≤ 0.001 *** | |
(U + S + A) / B | 9.16 ± 0.08 A | 7.11 ± 0.08 B | 9.3 ± 1.36 A | ≤ 0.001 *** | |
B: U༚S༚A | 1:8.81:0.26:0.1 | 1:6.84:0.19:0.07 | 1:6.88:0.19:0.07 | | |
Referencing Table 5, the analysis revealed that the essential amino acid (EAA) profile of BKF4 closely mirrors that of its purebred progenitors, aligning well with the FAO/WHO amino acid (AA) standards and demonstrating high nutritional value. Notably, the ratio coefficients (RC) for isoleucine, lysine, the combination of phenylalanine and tyrosine, threonine, and valine in both GB and SK or leucine in GB and BKF4 were above 1, indicating an abundance of these AAs suitable for nutritional enhancement. In contrast, the combined values of methionine and cysteine, as well as tryptophan across all groups, and specifically lysine in SK, showed RC values below 1, suggesting a relative deficiency. Tryptophan was notably absent, making it the primary limiting AA, with Methionine plus Cysteine identified as the secondary limiting AA.
For a detailed assessment of BKF4's nutritional quality, the Recommended Amino Acid Ratio Coefficient (RAA), Relative Concern (RC), and Score Relative to its Limiting Amino Acid (SRC), as defined by the FAO/WHO, were utilized. SRC’ values close to 100 indicate a higher protein nutritional value. The SRC values for GB, SK, and BKF4 were 54.86, 50.86, and 53.00 respectively, establishing a nutritional hierarchy of GB > BKF4 > SK. Moreover, higher E/N’ or E/T’ ratios suggest greater nutritional merit. When compared to the FAO/WHO's ideal protein benchmark, the E/T’ ratio for SK was below this standard, while the E/N’ ratios for GB and BKF4 exceeded it, underscoring BKF4's superior nutritional profile to SK.
The Essential Amino Acid Index’ (EAAI’) denotes the similarity of the EAA composition to the standard reference protein, with a value approaching 1 indicative of superior nutritional value. The EAAI’ values recorded for the samples stood at 93.12, 72.22, and 87.51 for GB, SK, and BKF4 respectively, reflecting a comparatively superior amino acid profile in BKF4 to SK.
Table 5
Ideal Protein Ratio Recommended by WHO/FAO35, called Protein Digestibility-Corrected Amino Acid Score(PDCAAS)
Amino Acid | FAO/WHO Scoring Pattern (g/100 g of protein) | RAA | RC |
Standard Value | GB | SK | BKF4 | GB | SK | BKF4 | GB | SK | BKF4 |
#Isoleucine | 4 | 3.8 | 3.5 | 3.7 | 0.95 | 0.88 | 0.91 | 1.14 | 1.35 | 1.13 |
#Leucine | 7 | 6.6 | 6.2 | 6.5 | 0.94 | 0.88 | 0.92 | 1.13 | 1.35 | 1.15 |
#Lysine | 5.5 | 6.8 | 2.6 | 7.1 | 1.24 | 0.47 | 1.29 | 1.50 | 0.71 | 1.60 |
#Methionine + Cysteine | 3.5 | 2.3 | 1.7 | 2.1 | 0.65 | 0.49 | 0.60 | 0.79 | 0.74 | 0.75 |
#Phenylalanine + Tyrosine | 6 | 6.3 | 5.7 | 6.1 | 1.05 | 0.95 | 1.02 | 1.26 | 1.45 | 1.26 |
Threonine | 4 | 3.9 | 3.4 | 3.7 | 0.97 | 0.85 | 0.92 | 1.17 | 1.30 | 1.15 |
Tryptophan | 1 | 0.0 | 0.0 | 0.0 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Valine | 5 | 4.2 | 3.6 | 4.0 | 0.84 | 0.72 | 0.79 | 1.01 | 1.10 | 0.98 |
E / T’(Left);SRC’(Right) | 40 | 44.11 | 38.41 | 43.95 | — | — | — | 54.86 | 50.86 | 53.00 |
E / N’(Left);EAAI’(Right) | 60 | 74.18 | 58.76 | 73.74 | — | — | — | 93.22 | 72.15 | 89.98 |
3.4 Fatty Acid Composition
In beef and lamb, the intramuscular fat in muscle contains 45–48 g/100 g of saturated fatty acids (SFAs), 35–45 g/100 g of monounsaturated fatty acids (MUFAs), and up to 50 g/100 g of polyunsaturated fatty acids (PUFAs)36. Table 6 presents the fatty acid profile identified in the intramuscular fat of the studied goat groups, revealing 18 different types of fatty acids. There are 6 types each of SFAs, MUFAs, and PUFAs, showing significant inter-group differences (P ≤ 0.01). Specifically, SFAs increased from 38.9–49.3%, MUFAs decreased from 48.2–42.9%, and PUFAs decreased from 12.8–7.9%, leading to a adverse compositional shift in relative content. Furthermore, IMF, BCFAs, EFAs, UFAs, TFAs, n-6FAs, UI, DFA, OFA, and h/H all demonstrate the highest content in SK, followed by GB, and the lowest in BKF4 (P ≤ 0.01). Both AI and TI values are utilized as markers for evaluating the risk of cardiovascular diseases, with higher values indicating a higher risk of cardiovascular diseases for individuals, and the outcome is disappointingly negative. However, the content of n-3FAs in BKF4 is significantly higher than in GB, specifically with a notable increase in three key bioactive fatty acids: ALA, EPA, and DHA. This leads to a substantial reduction in the n-6 / n-3 ratio from 28.9 in GB and 18.20 in SK to 6.56 in BKF4. In terms of individual fatty acids, most fatty acids exhibit a similar trend, except for Eicosenoic acid.
Table 6
Effects of Cross-breeding on Fatty Acid Compositiont of LD
Items | GB | SK | BKF4 | P-value |
Intramuscular Fat (IMF; expressed as g/100 g fresh LD tissue) |
IMF | 3.05 ± 0.59B | 6.08 ± 2.46A | 4.40 ± 1.23B | ≤ 0.001 *** |
Saturated Fatty Acids (SFAs; expressed as mg/100 g fresh LD tissue) |
Myristic acid (C14:0) | 15.90 ± 1.92C | 53.73 ± 2.84A | 22.10 ± 1.61B | ≤ 0.001 *** |
Pentadecanoic acid (C15:0) | ND | 15.50 ± 2.91A | 7.76 ± 0.07B | ≤ 0.001 *** |
Palmitic acid (C16:0) | 832.40 ± 104.0A | 957.04 ± 47.51A | 657.50 ± 45.05B | 0.002 ** |
Heptadecanoic acid(C17: 0) | 8.38 ± 0.29C | 61.57 ± 1.40A | 14.85 ± 3.60B | ≤ 0.001 *** |
Stearic acid (C18:0) | 510.40 ± 75.61B | 725.00 ± 46.13A | 462.43 ± 42.43B | ≤ 0.001 *** |
Docosanoic acid(C22: 0) | 6.31 ± 1.95b | 9.26 ± 0.07a | 8.08 ± 0.07ab | 0.033 * |
SFAs (g/100 g) | 1.37 ± 0.16B | 1.82 ± 0.01A | 1.17 ± 0.08C | ≤ 0.001 *** |
Monounsaturated Fatty Acids (MUFA; expressed as mg/100 g fresh LD tissue) |
Myristoleic acid (C14:1n5) | ND | 5.45 ± 0.35 | ND | — |
Palmitoleic acid (C16:1n7) | 44.58 ± 29.72b | 98.97 ± 1.47a | 49.90 ± 3.83b | 0.011 * |
Eicosenoic acid(C20: 1n7+ C20༚1n9) | 31.74 ± 2.47a | 10.08 ± 0.29b | 3.38 ± 0.46c | ≤ 0.001 *** |
Myristoleic(C24: 1n15) | ND | ND | ND | |
Elaidic acid(C18: 1n9t) | 10.57 ± 2.01B | 22.07 ± 1.53A | 7.97 ± 0.14C | ≤ 0.001 *** |
Oleic acid (C18:1n9 c) | 1301.20 ± 172.81B | 2120.00 ± 170.59A | 956.75 ± 40.98C | ≤ 0.001 *** |
Erucic acid(C22: 1n9) | ND | 5.35 ± 0.33 | ND | — |
MUFAs (g/100 g) | 1.39 ± 0.16B | 2.26 ± 0.17A | 1.02 ± 0.04B | ≤ 0.001 *** |
Polyunsaturated Fatty Acids (PUFA; expressed as mg/100 g fresh LD tissue) |
Cis-11,14-eicosadienoic acid (C20:2n6) | 10.76 ± 2.07 | ND | ND | — |
#Linoleic acid (LA, C18:2n6c) | 259.01 ± 34.51B | 442.0 ± 35.79A | 117.25 ± 22.78C | ≤ 0.001 *** |
#Alpha-linolenic acid (ALA, C18:3n3) | 10.59 ± 1.21C | 18.17 ± 0.76A | 14.21 ± 1.26B | ≤ 0.001 *** |
#Arachidonic acid (AA, C20:4n6) | 46.59 ± 5.08B | 130.33 ± 19.14A | 44.88 ± 3.44B | ≤ 0.001 *** |
#EPA(C20: 5n3) | ND | 7.20 ± 0.28 | 7.17 ± 0.42 | 0.921 |
#DHA(C22: 6n3) | ND | 6.08 ± 0.07A | 3.54 ± 0.41B | ≤ 0.001 *** |
PUFAs (g/100 g) | 0.33 ± 0.04B | 0.6 ± 0.03A | 0.19 ± 0.02 C | ≤ 0.001 *** |
Partial sums (g/100 g fresh LD tissue) |
Branched-chain fatty acids (BCFAs) | 0.84 ± 0.10 B | 1.03 ± 0.05 A | 0.68 ± 0.05 C | ≤ 0.001 *** |
EFAs | 0.32 ± 0.04 B | 0.60 ± 0.03 A | 0.19 ± 0.02 C | ≤ 0.001 *** |
UFAs | 1.72 ± 0.18 B | 2.87 ± 0.17 A | 1.21 ± 0.06 C | ≤ 0.001 *** |
TFAs | 3.09 ± 0.31 B | 4.69 ± 0.16 A | 2.38 ± 0.12 C | ≤ 0.001 *** |
n-6 | 0.31 ± 0.04 B | 0.57 ± 0.03 A | 0.16 ± 0.02 C | ≤ 0.001 *** |
n-3 | 0.01 ± 0.00 C | 0.03 ± 0.00 A | 0.02 ± 0.00 B | ≤ 0.001 *** |
Ratios (%) |
PUFAs / SFAs | 24.10 ± 4.32 B | 33.14 ± 1.69 A | 15.95 ± 1.33 C | ≤ 0.001 *** |
PUFA s/ MUFAs | 23.66 ± 2.92 A | 26.75 ± 2.38 A | 18.36 ± 1.56 B | ≤ 0.001 *** |
UFAs / TFAs | 55.56 ± 2.21 B | 61.12 ± 1.46 A | 50.70 ± 1.73 C | ≤ 0.001 *** |
SFAs:MUFAs:PUFAs:EFAs | 1:1.01:0.24:0.23 | 1:1.24:0.33:0.33 | 1:0.87:0.16:0.16 | |
Evaluation Index |
UI | 1.74 ± 0.18 B | 3.13 ± 0.1 A | 1.36 ± 0.04 C | ≤ 0.001 *** |
AI (%) | 52.80 ± 6.27 B | 40.92 ± 2.22 C | 61.96 ± 3.86 A | ≤ 0.001 *** |
DFA (g/100g) | 2.23 ± 0.25 B | 3.59 ± 0.15 A | 1.67 ± 0.09 C | ≤ 0.001 *** |
OFA (g/100g) | 0.85 ± 0.1 B | 1.01 ± 0.04 A | 0.68 ± 0.05 C | ≤ 0.001 *** |
TI | 1.5 ± 0.14 B | 1.14 ± 0.06 C | 1.7 ± 0.10 A | ≤ 0.001 *** |
h / H | 1.93 ± 0.28 B | 2.71 ± 0.16 A | 1.68 ± 0.11 B | ≤ 0.001 *** |
n-6 / n-3 | 28.90 ± 2.49 A | 18.20 ± 0.94 B | 6.56 ± 1.22 C | ≤ 0.001 *** |
3.5 Principal Component Analysis (PCA)
This study employed Principal Component Analysis (PCA) to thoroughly assess the value of BKF437. After standardizing the original data via the Z-score method, the eigenvalues and contribution rates of the principal components were computed, as detailed in Table 7. The analysis indicated that the quality influence factors of the three goat groups were predominantly governed by two principal components, which contributed 83.49% and 16.51%, respectively, to the variance explained. The mathematical expressions for these principal components, derived using data from Tables <link rid="tb3">3</link>–6 and 3–7, were as follows:
y 1 = 5.959X1 + 6.432 X2 + 5.082 X3 + 5.951 X4 + 6.985 X5 + 5.238 X6 + 7.034 X7 + 7.053 X8 + 5.07 X9 + 7.045 X10 + 7.008 X11 + 6.939 X12 + 7.06 X13 + 7.047 X14 + 7.047 X15 + 7.026 X16 + 6.844 X17 + 5.063 X18 + 7.023 X19 + 5.109 X20 + 7.013 X21 + 7.056 X22 + 7.048 X23 + 6.977 X24 + 7.057 X25 + 7.048 X26 + 5.072 X27 + 5.081 X28 + 5.115 X29 + 5.076 X30 + 5.074 X31 + 5.074 X32 + 7.036 X33 + 5.276 X34 + 5.122 X35 + 5.198 X36 + 5.119 X37 + 5.063 X38 + 5.107 X39 + 5.071 X40 + 6.983 X41 + 5.084 X42 + 5.065 X43 + 6.228 X44
y 2 = 1.7 X1 + 1.766 X2 + 2.9 X3 + 3.689 X4 + 2.313 X5 + 2.126 X6 + 2.925 X7 + 2.819 X8 + 2.827 X9 + 2.874 X10 + 3.016 X11 + 3.173 X12 + 2.732 X13 + 2.86 X14 + 2.862 X15 + 2.957 X16 + 3.317 X17 + 2.625 X18 + 2.968 X19 + 2.39 X20 + 3.002 X21 + 2.794 X22 + 2.853 X23 + 3.097 X24 + 2.782 X25 + 2.535 X26 + 2.845 X27 + 2.892 X28 + 3.019 X29 + 2.866 X30 + 2.855 X31 + 2.855 X32 + 2.471 X33 + 2.076 X34 + 3.038 X35 + 3.201 X36 + 3.029 X37 + 2.756 X38 + 2.995 X39 + 2.838 X40 + 2.308 X41 + 2.909 X42 + 2.786 X43 + 1.709 X44
In these expressions, the subscripts of X1, X2, X3,...,X33, X34 represented pH45, DL, MC, Ash, CP, IMF, EAAs, CEAAs, NEAAs, PAAs, TAAs, BCAAs, PAAs / TAAs, EAAs / TAAs, EAAs/ NC, EAAI, SRC, NI, BV, PER, Umami, Bitterness, Sweetness, Aromatic flavor, (U + S + A) / B, SFAs, MUFAs, PUFAs, BCFAs, EFAs, UFAs, TFAs, n-6, n-3, PUFAs / SFAs, PUFAs / MUFAs, UFAs / TFAs, UI, AI, DFA, OFA, TI, h / H, n-6 / n-3.
Additionally, as shown in Table 8, the order of impact on the quality of goats is pH45, IMF, NI, PUFAs / MUFAs, n-6, DL, Aromatic, MUFAs, Umami, DFA, MC, TI, PAAs, h / H, Ash, etc.
Table 7
Eigenvalues and Contribution Rate of the Principal Components
Main Components | Eigenvalues | Contribution rate, % | Cumulative Contribution Rate, % |
P1 | 36.736 | 83.49 | 83.49 |
P2 | 7.264 | 16.51 | 100.00 |
Table 8
Loading Matrix of Principal Components
Factor | X1 | X6 | X18 | X36 | X33 | X2 | X24 | X27 | X21 | X40 | X3 | X42 | X10 | X43 | X4 |
pH45 | IMF | NI | P/MUFAs | n-6 | DL | Aromatic | MUFAs | Umami | DFA | MC | TI | PAAs | h / H | Ash |
P1 | -0.102 | -0.823 | -0.998 | -0.863 | 0.975 | 0.371 | 0.916 | -0.989 | 0.952 | -0.99 | -0.979 | -0.977 | 0.984 | -0.996 | -0.11 |
P2 | -0.995 | -0.569 | -0.07 | 0.506 | -0.224 | -0.929 | 0.402 | 0.15 | 0.307 | 0.143 | 0.205 | 0.214 | 0.179 | 0.091 | 0.994 |
| 1.00021 | 1.00054 | 1.00045 | 1.00040 | 1.00040 | 1.00034 | 1.00033 | 1.00031 | 1.00028 | 1.00027 | 1.00023 | 1.00016 | 1.00015 | 1.00015 | 1.00007 |
Factor | X39 | X15 | X44 | X17 | X19 | X29 | X16 | X41 | X11 | X22 | X26 | X31 | X32 | X38 | X5 |
| AI | EAAs/ NC | n-6 / n-3 | SRC | BV | BCFAs | EAAI | OFA | TAAs | Bitterness | SFAs | UFAs | TFAs | UI | CP |
P1 | -0.954 | 0.986 | 0.167 | 0.783 | 0.962 | -0.946 | 0.965 | 0.922 | 0.947 | 0.995 | 0.987 | -0.987 | -0.987 | -0.998 | 0.924 |
P2 | 0.3 | 0.167 | -0.986 | 0.622 | 0.273 | 0.324 | 0.262 | -0.387 | 0.321 | 0.099 | -0.16 | 0.16 | 0.16 | 0.061 | -0.382 |
| 1.00006 | 1.00004 | 1.00004 | 0.99999 | 0.99999 | 0.99995 | 0.99993 | 0.99993 | 0.99992 | 0.99991 | 0.99988 | 0.99988 | 0.99988 | 0.99986 | 0.99985 |
Factor | X7 | X25 | X9 | X30 | X8 | X14 | X34 | X13 | X35 | X12 | X20 | X28 | X23 | X37 | |
EAAs | U + S + A/B | NEAAs | EFAs | CEAAs | E/TAAs | n-3 | P / TAAs | PU / SFAs | BCAAs | PER | PUFAs | Sweetness | U / TFAs | |
P1 | 0.973 | 0.996 | -0.991 | -0.985 | 0.992 | 0.986 | -0.785 | 0.999 | -0.939 | 0.878 | -0.952 | -0.98 | 0.987 | -0.942 | |
P2 | 0.23 | 0.087 | 0.132 | 0.171 | 0.124 | 0.165 | -0.619 | 0.037 | 0.343 | 0.478 | -0.305 | 0.197 | 0.158 | 0.334 | |
| 0.99981 | 0.99979 | 0.99975 | 0.99973 | 0.99972 | 0.99971 | 0.99969 | 0.99968 | 0.99968 | 0.99968 | 0.99966 | 0.9996 | 0.99957 | 0.99946 | |
Table 9
Principal Component Scores and Comprehensive Scores of three Goat Varieties
Principal Component | y1 | y2 | Y | Rank |
GB | 34.7 | 16.23 | 31.65 | 1 |
BKF4 | 12.67 | -12.63 | 8.49 | 2 |
SK | -47.37 | -3.6 | -40.14 | 3 |
Furthermore, integrating the data from Table 7 and Table 8, a comprehensive evaluation function for the principal components was developed, represented as: Y = 0.8349y1 + 0.1651y2. In this function, Y denotes the score factor, while y1 and y2 are the expressions for the two principal components. This formula allows for the calculation of comprehensive score values and rankings for meat quality among the three goat groups. According to the results presented in Table 9, the ranking in terms of meat quality is as follows: GB > BKF4 > SK.