Short communication: Effects of dietary N-carbamoylglutamate supplementation on the milk amino acid profile and mozzarella cheese quality in mid-lactating dairy cows.

N-Carbamoylglutamate (NCG) is an enhancer of Arg, which is a functional AA and could prevent cardiovascular disease and improve immunity. The present study was conducted to investigate the effects of supplementing NCG in diets of lactating cattle on the NCG concentration and AA composition of raw milk and on mozzarella cheese quality. Thirty multiparous cows with a mean body weight of 669 kg (standard deviation = 71) and days in milk of 176 (standard deviation = 55) were blocked based on parity and milk production and randomly assigned to 1 of 2 treatments: basal diet (CON) and basal diet supplemented with 40 g of NCG per day per cow (NCG). After 8 wk of treatment, raw milk samples were collected from the 2 groups for AA analysis and mozzarella cheese-making. Furthermore, the NCG concentration and distribution in milk and mozzarella cheese were detected. The AA concentration in milk was greater and the NCG concentration in raw milk was approximately 6 times greater in the NCG group than in the CON group. No NCG was detected in cheese from the CON group, and very little NCG (<1.0 μg/kg) of cheese was detected in the NCG group. Most of the dietary NCG was transferred into whey, stretch water, and brine during cheese production. No significant difference was found between the 2 groups on cheese texture and color except that hardness was lower in the NCG group. Overall, the results indicated that dietary supplementation of NCG could improve the NCG and AA concentrations in raw milk without affecting the quality of cheeses such as mozzarella.