五点采样法评估安格斯牛眼肌脂肪酸与蛋白表达优势研究OA

The aim of this study was to compare the effects of single-point and five-point sampling methods on the fatty acid compo-sition and expression of intramuscular fat deposition-related proteins in Angus beef cattle,to provide a scientific basis for the evalu-ation of beef quality in China,and to provide a reference for the breeding of beef cattle and the improvement of meat quality.The experiment was divided into two parts.In the first part,three 26-month-old Angus steers were randomly selected,and after slaugh-ter,each cow was sampled in the eye muscle area for fatty acid determination using single-point and five-point sampling methods,respectively,and Western blot for SCD,SREBP1,PPARγ,C/EBPΩ,FABP4,ACACA and FA SN,and in the second part,thirty 26-month-old Angus steers were randomly selected.Thirty 26-month-old Angus beef cattle were randomly divided into 2 groups of 15 cattle each by single-point sampling and five-point sampling methods,and the differences in the effects of marbling and slaugh-ter performance of Angus beef cattle were analyzed after slaughter,and samples were taken from the eye muscles for fatty acid as-say again afterward.In the single-point sampling group of Experiment 1,the levels of monounsaturated fatty acids(macadamia acid and palmitic acid)and polyunsaturated fatty acids(linoleic acid and γ-linolenic acid)were significantly lower than those in the five-point sampling group(P<0.05).Conversely,the level of saturated fatty acid(caprylic acid)was significantly higher than that in the five-point sampling group(P<0.05).At the protein expression level,the five-point sampling group exhibited significantly higher expression levels of PPARγ,C/EBPΩ,and SCD compared to the single-point sampling group(P<0.05).No significant differences were observed in the expression of SREBP1,FA BP4,A CA CA,and FASN(P﹥0.05),though a biological upward trend was noted.In Experiment 2,the single-point sampling group exhibited significantly higher saturated fatty acids and n-6/n-3 fatty acid ratios than the five-point sampling group(P<0.05).However,it showed significantly lower levels of unsaturated fatty acids,monounsaturated fatty acids/saturated fatty acids ratio,polyunsaturated fatty acids/saturated fatty acids ratio,n-6 fatty acids,and n-3 fatty acids com-pared to the five-point sampling group(P<0.05).Therefore,compared to single-point sampling,five-point sampling provides a more comprehensive reflection of the fatty acid composition and related protein expression characteristics in the sample.This advantage is primarily associated with its ability to detect higher unsaturated fatty acid content,a more favorable n-6/n-3 fatty acid ratio,and the upregulation of PPA Rγ,C/EBPΩ,and SCDprotein expression levels.