Effects of supplementing sweet sorghum with grapeseeds on carcass parameters, and meat quality, amino acid, and fatty acid composition of lambs

OBJECTIVE: Sweet sorghum is an important forage crop for ruminants, especially in low rainfall areas. Grapeseeds are an abundant by-product of wine-making and contain bioactive substances that can improve the antioxidant capacity of meat. We examined the effect of sweet sorghum forage with supplementary grapeseeds on carcass and meat quality in lambs. METHODS: Twenty-eight Small-tailed Han lambs (body weight = 19.1±1.20 kg), aged 3 to 4 months, were penned, and fed individually. The lambs were divided into four groups (n = 7 each) and were offered one of four diets: i) sweet sorghum silage; ii) sweet sorghum silage + grapeseeds; iii) sweet sorghum hay; and iv) sweet sorghum hay + grapeseeds. The grapeseeds were added to the concentrate at 6% DM and the diets were fed for 100 d. RESULTS: Sweet sorghum silage tended (p = 0.068) to increase hot carcass weight, while grapeseeds tended (p = 0.081) to decrease dressing percentage without affecting other carcass parameters. Lambs consuming supplementary grapeseeds increased (p<0.05) meat redness and tended to decrease (p = 0.075) concentration of methionine in meat. Lambs consuming sweet sorghum silage increased (p<0.001) water content of the meat and had a lower (p<0.05) concentration of n-6 polyunsaturated fatty acids (PUFA) and n-6:n-3 PUFA ratio than lambs consuming sweet sorghum hay. Saturated fatty acids content in meat was lowest (p<0.05) in lambs consuming sweet sorghum silage with grapeseeds. Lambs with supplementary grapeseeds tended (p<0.10) to increase eicosapentaenoic acid and docosahexaenoic acid and have a lower thrombogenic index than lambs not consuming grapeseeds. CONCLUSION: It was concluded that sweet sorghum with supplementary grapeseeds fed to lambs; i) improved the color of the meat to be more appetizing to the consumer; ii) tended to improve the fatty acids composition of the meat; and iii) lowered thrombogenic index of the meat.