Abstract: This study investigated the contents of longissimus muscle amino acid, contents of fatty acid, IMF and protein content of 21 Landrace with body weight 92.4～118kg stage. And relation degree and the changing rule with slaughter weight were analyzed, the objective was to investigate the appropriate slaughter body weight of Landrace suitable to the market. The results indicated that the effects of slaughter body weight on contents of longissimus muscle 17 amino acids of Landrace were significant except Met. But it on palmitic acid, stearic acid, oleic acid, linoleic acid and IMF were not significant. Inside, the most amino acid objects of Landrace with 110～118 kg body weight were extremely remarkable higher than Landrace with 92.4～100 kg body weight. Correlation analysis indicated that the most objects of carcass performance and meat qualities had remarkable relation to amino acids. Eye muscle area, lean percentage, skin and fat percentage, a24, shear force and IMF had remarkable relation to part fatty acids, but the other objects of carcass performance and meat qualities had no remarkable relation to fatty acids. The related between amino acids was very strong except Met. Palmitic acid had remarkable relation to stearic acid and linoleic acid, linoleic acid had remarkable relation to oleic acid. The correlate relation between amino acids and fatty acids was not remarkable. Regression relations results that 16 amino acids, total contents of amino acid, delicious amino acid contents, essential amino acid contents and essential amino acid contents accounted for the total amino acid proportion had remarkable regression relations with slaughter weight change of Landrace except Met. The trend increased or decreased of them were remarkable with slaughter weight growth. The generalized analysis test results believed that reasonable slaughter weight stage of Landrace was 110-118 kg.

Key words: slaughter weight; Landrace; longissimus muscle; amino acid; fatty acid; related relationship