Metabolomics Analysis Provides Novel Insights into the Difference in Meat Quality between Different Pig Breeds

The Chuanzang black (CB) pig is a new crossbred between Chinese local breeds and modern breeds. Here, we investigated the growth performance, plasma indexes, carcass traits, and meat quality characteristics of conventional DLY (Duroc × Landrace × Yorkshire) crossbreed and CB pigs. The LC-MS/MS-based metabolomics of pork from DLY and CB pigs, as well as the relationship between the changes in the metabolic spectrum and meat quality, were analyzed. In this study, CB pigs presented lower final body weight, average daily gain, carcass weight, and eye muscle area than DLY pigs (p ˂ 0.05). Conversely, the ratio of feed to gain, marbling score, and meat color score of longissimus dorsi (LD) were higher in CB than DLY pigs (p ˂ 0.05). Moreover, psoas major (PM) showed a higher meat color score and a lower cooking loss in CB than DLY pigs (p ˂ 0.05). Interestingly, CB pigs showed lower myofiber diameter and area but higher myofiber density than DLY pigs (p ˂ 0.05). Furthermore, the mRNA expression levels of MyHC I, PPARδ, MEF2C, NFATC1, and AMPKα1 were higher in CB than DLY pigs (p ˂ 0.05). Importantly, a total of 753 metabolites were detected in the two tissues (e.g., psoas major and longissimus dorsi) of CB and DLY pigs, of which the difference in metabolite profiles in psoas major between crossbreeds was greater than that in longissimus dorsi. Specifically, palmitic acid, stearic acid, L-aspartic acid, corticosterone, and tetrahydrocorticosterone were the most relevant metabolites of psoas major meat quality, and tetrahydrocorticosterone, L-Palmitoylcarnitine, arachidic acid, erucic acid, and 13Z,16Z-docosadienoic acid in longissimus dorsi meat were positively correlated with meat quality. The most significantly enriched KEGG pathways in psoas major and longissimus dorsi pork were galactose metabolism and purine metabolism, respectively. These results not only indicated improved meat quality in CB pigs as compared to DLY pigs but may also assist in rational target selection for nutritional intervention or genetic breeding in the swine industry.