Effects of different rumen-protected amino acids on fatty acids composition and flavor substances in subcutaneous and tail fat of Tibetan sheep

WANG Yuan; LIU Jiqian; HAN Lijuan; HOU Shengzhen; GUI Linsheng; YUAN Zhenzhen; SUN Shengnan; YANG Baochun

doi:10.13557/j.cnki.issn1002-2813.2025.20.003

Abstract：The experiment aimed to investigate the effects of rumen-protected amino acids added to the feed on the fatty acids composition and flavor substances in subcutaneous and tail fat of Tibetan sheep.A total of 45 healthy female Tibetan lambs of 2～3 months of age were randomly divided into three groups,with 15 replicates per group and one sheep per replicate.The GP-0,GP-2,and GP-3 groups were supplemented with 0.50 g/kg conventional methionine,0.50 g/kg rumen-protected methionine,and 0.25 g/kg rumen-protected methionine+0.25 g/kg rumen-protected cysteine in the basal diet premix,respectively.The pre-test period was seven days and the formal test period was 120 days.The results showed that the subcutaneous fat and tail fat content of the GP-3 and GP-2 groups was significantly higher than that of the GP-0 group(P＜0.05),while the concentrations of arachid acid and erucic acid were significantly lower than that of the GP-0 group(P＜0.05).A total of 36 and 41 known flavor compounds were detected in subcutaneous fat and tail fat,respectively.According to the ROAV,furfuryl thiol,butyraldehyde,nonanal,propionaldehyde,2-pentanone,ethyl acetate,and ethyl isovalerate were the main flavor contributors to the tail fat of Tibetan sheep,while the main contributors to the subcutaneous fat flavor of Tibetan sheep were furfuryl thiol,butyraldehyde and acetomon.Through the correlation analysis of fatty acids and flavor substances,it was found that fatty acids such as docosahexenoic acid,20-carbodienoic acid,and heptadecanoic acid will promote the formation of key flavor substances such as ethanol,nonanal,furfuryl thiol,and heptadecanoic acid in Tibetan sheep toil fat.The study shows that supplementing rumen-protected amino acids can enhance the subcutaneous and tail fat content and nutritional value of Tibetan sheep,with the combined addition of rumen-protected methionine and rumen-protected cysteine proving particularly effective.