Comparisons of carcass traits, meat quality, and serum metabolome between Shaziling and Yorkshire pigs

This study aims to compare the meat quality of Shaziling and Yorkshire pigs and to find the potential indicator in serum for superior meat quality. Six Shaziling and Yorkshire pigs at 30, 60, 90, 150, 210, and 300 d of age were selected to examine carcass traits, meat quality, and serum metabolome. The results showed that the body weight, carcass length, and loin eye area of Shaziling pigs at 150, 210, and 300 d of age were significantly lower than those of Yorkshire pigs (P < 0.05). Shaziling pigs at 150 and 300 d of age had significantly lower backfat thickness than Yorkshire pigs (P < 0.05). Compared with Yorkshire pigs, Shaziling pigs at all 6 ages had a lower lean percentage and a higher fat percentage (P < 0.05). At 60, 90, and 150 d of age, the post-mortem pH-decline, b∗ value (yellowness), and drip loss of Shaziling pigs were significantly lower than those of Yorkshire pigs (P < 0.05). Moreover, at 150 d of age, Shaziling pigs had significantly higher a∗ value (redness) and intramuscular fat (IMF) content than Yorkshire pigs (P < 0.05). Correlation analysis between the top 40 metabolites and phenotypes indicated that L-carnitine had positive correlations with fat percentage, pH24h, and IMF content, but had negative correlations with lean percentage, L∗ value (lightness), and b∗ value (P < 0.05). Serum L-carnitine content, fat percentage, pH24h, and IMF content all decreased first and then increased as the pigs grew, which verified the positive correlations between L-carnitine and these phenotypes. In conclusion, Shaziling pigs have a slower growth rate but a better meat quality than Yorkshire pigs. The meat quality of Shaziling pigs is the best from 150 to 210 d of age. This study suggests that a higher serum L-carnitine content is a promising indicator for better meat quality.