Chinese dairy industries have developed rapidly, providing consumers with high-quality sources of nutrition. However, many problems have also appeared during the development process, especially the low quality of milk. To improve milk quality, a large amount of concentrated feed is usually added to the diet within a certain period of time, which increases the milk production to a certain extent. However, long-term feeding with high-concentration feed can lead to subacute rumen
acidosis. Therefore, the present study aimed to determine the effect of adding a
buffer on subacute rumen
acidosis, and the improvement of milk production and milk quality. We also aimed to study the mechanism of promoting mammary gland lactation. A total of 12 healthy mid-lactating goats were randomly divided into two groups, they were high-grain diet group (Control) and buffering agent group. To understand the effects of high-grain diets with
buffers on
amino acids in jugular blood and the effects of
amino acids on
milk protein synthesis, Milk-Testing™ Milkoscan 4000, commercial kits, and high-performance liquid chromatography (HPLC) measurements were integrated with the
milk protein rate, the
amino acid concentration in jugular venous blood samples, quantitative real-time PCR, comparative proteomics, and western blotting to study differentially expressed
proteins and
amino acids in mammary gland tissues of goats fed high-grain diets. Feeding lactating goats with buffering agent increased the percentage of
milk protein in milk, significantly increased the
amino acid content of jugular blood (p < 0.05), and increase the
amino acid transporter levels in the mammary gland. Compared with the high-grain group, 2-dimensional electrophoresis technology, matrix-assisted
laser desorption/ionization-time of flight/time of flight proteomics analyzer, and western blot analysis further verified that the expression levels of
beta casein (CSN2) and
lactoferrin (LF)
proteins in the mammary glands of lactating goats were higher when fed a high-grain diets and
buffers. The mechanism of increased
milk protein synthesis was demonstrated to be related to the activation of
mammalian target of rapamycin (mTOR) pathway signals.