Another important benefit of balancing for amino acids is the effect on milk composition (Table 1). The milk protein content is very important not only because of its repercussion on the milk price received but also because of the effect on cheese production. Because the most important factor affecting the cheese yield (amount of cheese produced from one kg of milk) is milk casein. Cheese manufacturing is a dual process of concentration and biological transformation of milk components into gustatory and aromatic compounds that determine the unique characteristic of cheese. The quality and quantity of cheese depend on the amount of milk casein (KIR-18-00074, 19-20467, Storry et al., 1983). Cheese-making properties are therefore improved by selecting high casein milk (Wedholm et al., 2006, Chitchyan et al., 2009). Casein's content of milk protein is about 80 %. Balancing the diets for amino acids improves milk protein content (Table 1). Additionally, there is strong evidence that well-balanced diets can improve the casein content of milk protein. As a result, a double positive effect on cheese yield.
It is also remarkable that balancing for Methionine and Lysine requirements improves the antioxidant animal capacity, better health status and immunometabolism. Apart from participation in the very-low-density lipoprotein (VLDL) synthesis, Met and Lys have another important role in fat metabolism. They are both required for the synthesis of carnitine, essential for the transport of non-esterified fatty acids (NEFA) from the cytosol into the mitochondria for subsequent fatty acid oxidation (Drackley, 1999). Moreover, it is well known that carnitine plays additional important roles in protecting organisms from oxidative stress, promoting substrate oxidation in brown adipose tissue, and regulating energy partitioning in the body (Wu, 2013).
