Comparison of Growth Performance and Meat Quality Traits of Commercial Cross-Bred Pigs versus the Large Black Pig Breed

SIMPLE SUMMARY: Emphasis on improving meat quality is growing in the meat industry. Pigs under the same diet and environment could present with difference in meat quality if they have diverse genetic backgrounds. The Large Black pig is a British native pig breed which is famous for its hardness and resistance to extensive farming; compared with commercial cross-bred pigs, they have a slower growth rate. The aim of this study is to investigate the carcass and meat quality traits of Large Black pigs and commercial cross-bred pigs in relation to their transcriptome profiles, and consequently clarify the phenotypic and genotypic differences between these two groups of pigs. The results showed that Large Black pigs had greater intramuscular fat content than commercial cross-bred pigs, while the growth performance of commercial cross-bred pigs was better, and the transcriptomic differences between these two groups of pigs may be the cause of meat quality and growth performance variances. The outcome of the study provides new sights into the adoption of the Large Black breed in the pig industry. ABSTRACT: The meat quality of different pig breeds is associated with their different muscle tissue physiological processes, which involves a large variety of genes related with muscle fat and energy metabolism. Understanding the differences of biological processes of muscle after slaughter is helpful to reveal the meat quality development of different breeds. Therefore, eight native Large Black pigs (BP), with high fat content in meat, and seven cross-bred commercial pigs (CP), which had a high feed efficiency with high lean meat, were used to investigate the differences in their meat quality and RNA transcriptomes. The average daily gain (ADG) and hot carcass weight (HCW) of CP were higher than BP, but the back-fat thickness of BP was higher than CP (p < 0.05). The CP had higher a* (redness) but lower h (hue angle) than BP (p < 0.05). The metmyoglobin (MMb) percentage of CP was higher (p < 0.05) than BP. The fat content and oxygen consumption of longissimus dorsi (LD) muscles in BP were higher (p < 0.05) than CP. BP had higher monounsaturated fatty acids (MUFA) content, but CP had higher polyunsaturated fatty acids (PUFA) content (p < 0.05). The RNA-seq data highlighted 201 genes differentially expressed between the two groups (corrected false discovery rate (FDR) p < 0.05), with 75 up-regulated and 126 down-regulated genes in BP compared with CP using the fold change (FC). The real-time PCR was used to validate the results of RNA-seq for eight genes, and the genes related to lipid and energy metabolism were highly expressed in BP (p < 0.05). Based on the results, BP had superior intramuscular fat content to CP, while the growth performance of CP was better, and the transcriptomic differences between these two groups of pigs may cause the meat quality and growth performance variance.