The Research On Relationship Between APM And The Changes Of Milk-proteins, Serum Protein And Milk Fat

In order to further explore the causes of instability of the cow suffering from alcohol-positive milk (APM) and the mechanism of APM. I isolated the major milk protein components of skim milk by SDS-PAGE electrophoresis and gel image analysed the relative percentage of the milk protein components with gel imaging system.At the same time, I made a comprehensive testing on 17 kinds of amino acids in APM.In the perspective of Protein Metabolism,I made a comprehensive analysis of relationship among the major components of milk protein changes, changes in amino acid content and instability of APM. The major protein components of serum were isolated by cellulose acetate membrane electrophoresis, I analyzed the changs of relative percentage of protein contents. At the same time, in order to research the relationship between changes of fatty acid components and APM , The fatty acid composition was detected with Gas– MS;I analysed the relative percentage changes of the fatty acid content.These provided a theoretical basis for further study on the pathogenesis. The experimental results showed that:1. The main milk protein components in Skim milk were separated by sodium dodecyl sulfate polyacrylamide gel electropheresis(SDS-PAGE), dyed with Coomassie brilliant blue, and analysed with gel imaging analystem. From anode to cathode, it showed: serum albumin (SA), immunoglobulin heavy chain (lgG - H),α-casein protein (α-CN),β-casein (β-CN),κ-casein (κ-CN),β-lactoglobulin (β-LG),α-lactoglobulin (α-LG) and other major protein components (Figure 1-1). The relative percentage of the milk protein components are analysed with gel imaging system, Compared with normal milk, changs of alcohol-positive milk in the total milk protein were not significant (P>0.05); total casein (tCN) were significantly lower than normal milk (P <0.05); theα-CN in casein protein had no obvious change (P>0.05),butβ-CN was significantly higher (P<0.05),κ-CN decreased obviously(P<0.01).The major protein components in milk of the cow suffering from alcohol-positive milk have changed. The stability of protein casein micropheres was seriously damaged, The changes of main milk proteins of APM destroy the stability of casein microballoons acutely. Decreased stability of milk colloid causes alcohol experiment positive.2. 17 kinds of amino acid were analysed, and it showed that (compared with normal milk), the contents of majority of amino acids in APM had no significant changes(P>0.05), cystine (Cys) content was significantly lower (P <0.01), but Arginine(Arg) increased significantly (P<0.01); leucine (Leu) were significantly higher (P<0.05). Disulfide link formed by Cys played an important role in the stability of the protein; Leu had isobutyl with a strong hydrophobicity; Arg contains guanidinium group with positively charged, Arg contents increased so that the electrostatic repulsion in inter-microsphere weakened. At the same time, the ionic attractiveness of the surrounding ion also reduced and peripheral hydration shell was thinningz, so that the stability of the whole milk colloid reduced further.3. After serum was separated by cellulose-acetafolic electrophoresis, it took on four electrophoresis spectrum, according to transport ratio, it shows by turns albumin,α-globulin,β-globulin andγ-globulin (Figure 3-1 ).About the serum protein contents of the cows suffering from alcohol-positive milk, total serum protein content and albumin / globulin (A /G) values had not changed significantly (P>0.05). In the serum protein components, albumin andα-globulin had no obvious changes(P>0.05); However, the relative percentage ofβ-globulin was significantly higher (P<0.01), andγ-globulin was significantly higher (P <0.05). These changes of serum protein components probably resulted from vivo oxidative damage and lower thyroid function.4. The analysis of fatty acid showed that in the experiment, seven kinds of fatty acids in milk were tested, of which saturated fatty acids (SFA) had 4 kinds: myristic acid, pentadecane acid, hexadecanoic acid and stearic acid; and three kinds of unsaturated fatty acids: palmitoleic acid, linoleic acid and oleic acid (Figure 4-1).Compared with normal milk, the ratio of butter fat in APM had no obvious changes (P> 0.05); the total saturated fatty acids(SFA) in milk had no significant changes, but the a pentadecane acid in saturated fatty acids trended higher (P <0.01); unsaturated fatty acid (UFA)in milk trended upwards (P <0.01), meanwhile conjugated linoleic acid (CLA)in unsaturated fatty acid showed obvious rising trend (P <0.01 ). The process of linoleic acid inverting CLA create a large number of create, CLA increased, which showed that oxidation of free radical in linoleic acid reacted strongly, while activity of antioxidant enzymes in vivo declined, so that the body's ability to clear free radicals reduced, eventually it resulted in the existence of many free radicals,and caused the breast tissue taking on micro-damage,making abnormal secretion of breast milk,so that it resulted in alcohol-positive milk.