Effects of ammonium chloride addition level in diet on lipidomics and flavor compounds of intramuscular fat in Tibetan sheep

MA Qingling; WANG Jiancui; HE Juyuan; HOU Shengzhen; YANG Chao

doi:10.13557/j.cnki.issn1002-2813.2025.23.003

Abstract：The experiment aimed to investigate the effects of adding different levels of ammonium chloride to the diet on the morphology,fatty acid composition,lipidomics,and volatile flavor compounds of intramuscular adipose tissue in Tibetan sheep.A total of 80 healthy two-month-old early weaned Tibetan ewes with an average weight of(16.22±1.01)kg were randomly divided into four groups,with five replicates per group and four ewes per replicate.Each group was supplemented with 0(group CON),1.49%(group NH1),2.24%(group NH2),and 3.01%(group NH3)of ammonium chloride in the basal diet,respectively.The pre-test period was 15 days,and the formal test period was 90 days.The results showed that the groups NH2 and NH3 had different sizes and disordered arrangement of adipocytes,and the group NH3 showed cell rupture.The addition level of ammonium chloride had a significant effect on the density and diameter of adipocytes(P<0.05),as well as on the concentrations of intramuscular saturated fatty acids(SFA),monounsaturated fatty acids(MUFA),polyunsaturated fatty acids(PUFA),n-3 polyunsaturated fatty acids(n-3 PUFA),and n-6 polyunsaturated fatty acids(n-6 PUFA)(P<0.05).A total of 198 differential lipid molecules were screened by pairwise comparison of each group of samples,most of which were glycerides such as diglycerides and triglycerides,as well as glycerophosphatide such as phosphatidylcholine and phosphatidylethanolamine.The addition level of ammonium chloride in feed had a significant effect on the content of volatile flavor compounds in intramuscular fat(P<0.05).The study shows that when the level of ammonium chloride added to feed is≥2.24%,it can reduce the accumulation of functional fatty acids and characteristic flavor compounds in intramuscular fat by disrupting the structure of adipocytes,inhibiting fatty acid synthesis and metabolism.Meanwhile,the significant accumulation of ammonia in intramuscular fat ultimately has a negative impact on the flavor and quality of Tibetan sheep.