Effects Of Dietary Protein Levels And Its Cycle Changes On Muscle Quality And Related Gene Expression In Male Calyes

Experiment 1:In order to study the effect of dietary protein levels on the muscle quality and related gene expression of milk male calves,the Holstein milk male calves of 4-6 months old in this experiment were selected to have the same body weight and good body condition.Twelve healthy dairy bull calf were randomly divided into 2 groups with a single factor,feeding a high protein group(with a crude protein level of 17.27%)and a low protein group(with a crude protein level of 12.50%),respectively.The results showed that:1.There was no significant difference in hydraulic and cooked meat rates between the two experimental groups(P>0.05).In terms of shear force,there was no significant difference between the high and low protein groups(P>0.05).Compared with the high protein group,the 45 min pH and 24 h pH of the low protein group were slightly different,but the difference was not significant(P>0.05).2.There was no significant change in dry matter content in the muscles of the high and low protein test groups(P>0.05).The crude protein content in the muscle of the high protein diet group was significantly higher than that of the low protein diet group(P<0.05).There was no significant difference in crude fat content between the two groups of high and low protein(P>0.05).There was no significant change in the crude ash content of the high and low protein groups(P>0.05).3.The contents of threonine,proline,leucine and lysine in the high protein group were significantly higher than those in the low protein group(P<0.05).Feeding high protein level diets had no significant effect on histidine,arginine,methionine and phenylalanine content(P>0.05);The contents of alanine,glycine,glutamic acid,aspartic acid and cystine in the non-essential amino acids were increased by the increase of dietary protein levels,and the difference was significant(P<0.05).Dietary protein levels had no significant effect on the content of proline,tyrosine and serine(P>0.05).4.In this study,the fatty acids,monounsaturated fatty acids and polyunsaturated acids were tested.There were no significant differences in the content of myristic acid,palmitic acid,leucovoric acid,stearic acid and arachidic acid in saturated fatty acids(P>0.05).The difference in total saturated fatty acids was also not significant(P>0.05)),The linoleic acid content in the muscles fed the high protein level of unsaturated fatty acids was significantly higher than that in the low protein level diet group(P<0.05).The total amount of unsaturated fatty acids and UFA/SFA differences were not significant(P>0.05).5.From the perspective of related gene expression,compared with the high protein group,the expression of FABP4 gene in the muscle of the low protein group was significantly higher in the protein group,and the difference was significant(P<0.05).There was no significant difference in the expression of DGAT1,H-FABP and SCD genes in the muscles of the two experimental groups(P>0.05).Experiment 2:In this study,12 Holstein milk male calves of 4-6 months old with similar body weight and good health were selected and randomly divided into 2 groups by single factor,each group of 6 cows,respectively,stable protein group(feeding The diet with a crude protein level of 14.89%),the flucan protein group(fed with crude protein levels of 12.50%and 17.27%at 48 h intervals).The results show:1.The cooked meat rate and the hydraulic strength of the stable protein group were not significantly different from those of the fluctuin group(P>0.05).In terms of shear force,the fluctuin group was slightly higher than the stable protein group but had no significant change(P>0.05).Compared with the stable protein group,the difference between the 45 min pH and the 24 h pH of the fluctuin group was not significant(P>0.05).2.There was no significant change in the dry matter content in the muscles of the stable protein group and the fluctuin test group(P>0.05).Compared with the stable protein group muscle,the crude protein content in the muscle of the fluctuin group increased(0.05<P<0.1);There was no significant change in the crude fat and crude ash content in the muscles of the stable proteome and fluctuin groups(P>0.05).3.The content of histidine in the muscles of the diet group fed with the wave protein level was significantly higher than that of the stable protein group(P<0.05),while the protein in the wave protein diet group was compared with the diet protein group fed with the stable protein.There was no significant change in acid,threonine,proline or leucine(P>0.05).The lysine content in the muscles of the two diets was significantly different.The stable protein level diet group and the wave protein level group were respectively It was 1.03±0.05 and 3.04±0.47;the total amount of essential amino acids in the muscles fed the wave protein group was higher than that in the muscles fed the stable protein group(0.05<P<0.1).In terms of non-essential amino acid content,the levels of glutamic acid,serine and aspartic acid in the muscles fed the wave protein diet were significantly increased(P<0.05),while tyrosine and alanine.The content of cystine and proline was not significantly different(P>0.05).4.In this study,the content of saturated fatty acids,monounsaturated fatty acids and polyunsaturated acids in muscles was determined.Among them,the differences of myristic acid,palmitic acid,pearlic acid,stearic acid and arachidic acid in saturated fatty acids were not significant.(P>0.05);the content of heptadecenoic acid in the muscles fed the high protein level of unsaturated fatty acids was significantly higher than that in the diets fed the low protein level(P<0.05).UFA in the test results The difference between/SFA and PUFA/SFA was not significant(P>0.05),but the total fatty acid content in the muscles of the stable protein group was significantly higher than that in the folic protein level diet group(P<0.05),which was 23.94±0.69 and 22.95±0.15.5.Compared with the stable protein group,the expression of FABP4 gene in the muscle of the fluctuin group was significantly higher than that of the stable protein group,but the difference was not significant(P>0.05);There was no significant difference in the expression of DGAT1 gene(P>0.05).The expression of H-FABP in the stable protein group and the ferulolin group was not significantly different(P>0.05).Compared with the stable protein group,the expression was not significant.The gene expression of SCD in the muscle of the test group fed the wave protein group was significantly lower than that of the stable protein group(P<0.05).