Effect of N-acetyl-l-methionine supplementation on lactation performance and plasma variables in mid-lactating dairy cows.

The objective of current study was to investigate the effect of N-acetyl-l-methionine (NALM) supplementation on lactation performance and plasma variables in mid-lactating dairy cows. Forty-eight multiparous cows were blocked into 12 groups based on parity, days in milk, and milk production and were randomly assigned to 1 of the 4 treatments: 0, 15, 30, or 60 g/d of NALM per cow to supplement the basal diet. The experiment was conducted over a 13-wk period, with the first week as adaptation. The yields of milk, fat-corrected milk, and milk lactose were increased quadratically, and energy-corrected milk yield tended to increase with increased NALM supplementation in a quadratic manner. The dry matter intake, milk protein yield, milk fat yield, contents of milk composition (protein, fat, lactose, total solids, and milk urea nitrogen), feed efficiency, and body weight change were not affected by NALM supplementation. In addition, plasma methionine concentration was increased quadratically, and proline, total nonessential AA, and total AA concentrations were significantly higher in the 30 g/d group compared with that of the control group. However, other AA and total essential AA concentrations were not affected with supplementation of NALM. Adding NALM increased concentrations of total protein and globulin in plasma, but decreased plasma urea nitrogen concentration in a quadratic manner. Meanwhile, plasma malonaldehyde concentration decreased linearly as doses of NALM addition increased. Our results suggested that the supplementation of NALM improved milk yield and protein synthesis in the liver, and lowered lipid peroxidation in mid-lactating dairy cows.

Short communication: Effects of dietary addition of N-carbamoylglutamate on milk composition in mid-lactating dairy cows.

The present study was conducted to investigate the effect of N-carbamoylglutamate (NCG) on milk production and composition in mid-lactating Holstein dairy cows. Sixty multiparous cows with a mean body weight of 669 kg (standard deviation = 71) and 176 days in milk (standard deviation = 55) were blocked based on parity and milk production and randomly assigned into 4 treatments, a basal diet supplemented with 0, 10, 20, or 40 g of NCG/d per cow. Milk yield and composition were recorded weekly, whereas dry matter intake and plasma variables were determined every 2 wk. The results showed that the addition of NCG had no effect on the dry matter intake and milk yield of the cows. Milk fat content and yield increased linearly with NCG addition. The contents of milk protein and total solid also increased linearly in the cows fed NCG, whereas the yield of protein was not affected by the treatments. Conversely, dietary addition of NCG increased the plasma nitric oxide content in a quadratic manner. Moreover, addition of NCG linearly increased the plasma Arg content. Overall, the results indicate that dietary NCG addition increased the milk protein and fat contents, which improved the milk quality of lactating dairy cows.

Mechanism of the therapeutic effect of anisodamine in disseminated intravascular coagulation: study of platelet adhesion and aggregation, malondialdehyde, thromboxane B2, 6-keto-prostaglandin F1 alpha, and microcirculation.

Acute disseminated intravascular coagulation (DIC) is a life-threatening condition that may be encountered in many situations, especially in cases of shock with uncontrollable hemorrhage. Anisodamine, an alkaloid extracted from a Chinese herb, is well known for its dramatic therapeutic effect on DIC. Sixty male rabbits were used to establish an acute DIC model. A total of 240 blood samples were taken for laboratory assays of changes in blood coagulation factors, platelet count, platelet adhesion, platelet aggregation, malondialdehyde (MDA), thromboxane B2 (TXB2), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). Changes of the microcirculatory status and the rate of the blood flow in the conjunctival capillaries of 60 rabbits were observed with WXS-II microcirculation microscope. Pathological sections of the lungs and kidneys were studied. Our investigation showed the presence of microthrombi in the microvasculature. After treatment with anisodamine, the prothrombin time stayed in the normal range, fibrinogen consumption was lessened, adenosine-diphosphate-induced platelet aggregation was inhibited, thromboxane B2 and malondialdehyde concentrations were significantly lower than in the control group, and the elevated quantity of 6-keto-PGF1 alpha was spared. We concluded that the anti-platelet-aggregating, microcirculation-facilitating, thromboxane-B2-inhibiting, malondialdehyde-inhibiting, and 6-keto-PGF1 alpha-sparing effects of anisodamine are the important mechanisms of its dramatic therapeutic effect on DIC.