چكيده انگليسي :
Today, liver function is a critical aspect of metabolic homeostasis in dairy cattle, as the liver plays a central role in nutrient metabolism and detoxification. Blood amino acid concentration has been suggested as a potential indicator of liver function in dairy cows, because amino acids are both metabolized and synthesized by the liver. The relationship between blood amino acid concentrations and liver function in newborn Holstein dairy cows is an active research area; that conflicting results have been reported in the articles. In addition, the effect of blood amino acid concentration on liver function in newborn Holstein dairy cows is an important indicator in determining the health and productivity of the herd. The present study was conducted with the aim of investigating the relationship between liver function and the concentration of amino acids in the blood of newborn Holstein dairy cows. In this plan, among 60 Holstein dairy cows with almost similar weight and score, which had more than two pregnancies; Blood sampling was done on the 3rd and 28th days after calving. The animals in question did not have any special problems in terms of appearance, reproduction, hard birth, placental retention, and twin births, and they were the same in terms of housing and diet (expectation of calving and newborn cows). . The current project was carried out in the fall of 2019 at Fazil Livestock Company. Blood sampling was done in the mornings after milking from the tail vein, and in order to determine the liver index, cholesterol, bilirubin and albumin were measured. Also, the concentration of amino acids in the blood with The use of HPLC device was measured on the 3rd day after calving. Nevertheless, in the present project, Holstein dairy cows were divided into two groups based on liver function: 1) the number of 40 cows with positive liver function. 2) Number of 20 newborn cows with negative liver function. The results showed that in the descriptive statistics between the average groups with positive and negative liver function in Holstein dairy cows and the concentration of amino acids (histidine, leucine, lysine, methionine, phenylalanine, arginine, tyrosine, aspartic acid, glutamic acid, alanine , citrulline, ornithine, threonine, asparagine, glycine, serine, glutamine, non-essential amino acids and semi-essential amino acids) there is no significant relationship. But there is a direct and significant relationship between amino acid concentration (isoleucine, tryptophan, valine and all essential amino acids) with liver function in Holstein dairy cows (P<0.05). Other results also showed that amino acids (isoleucine, leucine, tryptophan, valine and asparagine) have a significant correlation with liver function in Holstein dairy cows(P<0.05) and the correlation of other amino acid concentrations with liver function in Holstein dairy cows is not significant.The strongest correlation was related to valine with a correlation coefficient of 0.28, followed by asparagine with a correlation coefficient of 0.26. Also, the analysis of the main components showed that (phenylalanine and valine, alanine and histidine) are effective on liver function. Principal component analysis to estimate the relationship between blood amino acids and liver function in newborn Holstein dairy cows shows that all amino acids have a positive and direct concentration relationship with liver function. Therefore, by analyzing the network analysis between acids Blood amines were found to be most closely related to valine amino acid(P<0.01). In general, the results showed that some amino acids, especially valine amino acid, can have a significant effect on the production efficiency and improvement of liver function.
