The Effect of Rearing Conditions on Carcass Traits, Meat Quality and the Compositions of Fatty Acid and Amino Acid of LTL in Heigai Pigs

SIMPLE SUMMARY: People’s demand for meat consumption has transformed from quantity to quality. The rearing condition is one of the factors affecting meat quality. However, the effects of different rearing conditions on the production of Chinese indigenous pig breeds are still barely understood. In this study, Heigai pigs (a Chinese indigenous pig breed) were raised in the indoor feeding farm and the grazing farm to investigate the effects of different rearing conditions on carcass traits, meat quality and the compositions of fatty acid and amino acid. Grazing farm pigs tended to increase shear force, while significantly increasing the saturated fatty acid ratio and decreasing the unsaturated fatty acid ratio to alter the composition of fatty acids of longissimus thoracis et lumborum. The present study provides an experimental reference for regulating the production of superior meat quality pork of Chinese local breed pigs. ABSTRACT: The present study evaluates the influence of captivity and grazing rearing conditions on the carcass traits, meat quality and fatty acid profiles of Heigai pigs. Ten Heigai pigs with market weight were randomly selected from both the indoor feeding farm and outdoor grazing farm groups (FF and GF; five pigs per group) for measuring production performance. The results showed that the shear force of longissimus thoracis et lumborum (LTL) in the GF group tended to increase (p = 0.06), and triglyceride and cholesterol contents in LTL and psoas major muscle (PMM) of the GF group significantly increased and decreased, respectively (p < 0.05). The proportion of saturated fatty acids (SFA) was significantly increased (p < 0.05) in the GF group. Meanwhile, the ratios of unsaturated fatty acid (UFA), polyunsaturated fatty acid (PUFA), monounsaturated fatty acid (MUFA) and the content of flavor amino acid of the LTL in the GF group were significantly decreased (p < 0.05). The GF upregulated the expression of MyHC-IIb and lipogenic genes, such as GLUT4 and LPL (p < 0.05), in LTL and PMM, but downregulated the expression of MyHC-I, MyHC-IIa, PPARγ and leptin (p < 0.05). In conclusion, these results suggested that the different rearing conditions can alter the meat qualities by mediating the muscle fiber type and lipid metabolism of Heigai pigs.