Effects of dietary supplementation of N-carbamylglutamate on lactation performance of lactating goats and growth performance of their suckling kidlets

摘要

Arginine is one of the conditional essential amino acids for immature mammals. The deficiency of arginine in the diet may constrain growth and development of newborn kidlets through affecting the milk performance of lactating goats. In our present study, lactating crossbred of Boer goat (Capra hircus) and Yangtse River Delta White (Haimen) goat with twin male suckling kidlets were used to investigate the effects of dietary supplementation of N-Carbamylglutamate (NCG) on lactation performance of lactating goats and growth performance of their suckling kidlets. At d 0 of lactation, thirty-two lactating goats (BW=40.21 +/- 2.16 kg) and their sixty-four twin male kidlets (BW=2.10 +/- 0.11 kg) were randomly allocated to 4 groups, which were fed diet contained different levels of NCG (0, 1 g/d, 2 g/d, or 3 g/d per goat respectively) for 42 days. Body weights (BW) of lactating goats and kidlets, dry matter intake, milk yield, parameters (amino acids, biochemical indices) of serum and milk, morphology of rumen papilla and jejunum villus were determined. The results showed that average daily gain (ADG) of lactating goats supplemented with NGC was significantly higher than that of the control group. The milk yield of lactating goats of 2 g/d NCG-supplementary groups were markedly higher than that of the control group at d 21 and d 42. The dietary NCG greatly increased the plasma NO (+19.94%-41.88%, P 0.05), insulin, arginine, citrulline and ornithine and decreased the plasma NH3 (-22.86%-38.85%, P 0.05) and urea (-19.32%-29.70%, P 0.05). The contents of milk protein, putrescine, insulin, NO and GH in goats of 2 g/d NCG supplementary group were significantly higher than that of the control group (P 0.05). Maternal dietary NCG increased the length, thickness of muscularis and density of ruminal papillae (P 0.05) of the kidlets at d 42. In summary, maternal dietary 2 g/d NCG supplementation enhanced the growth performance of suckling kidlets and milk performance of lactating goats. Therefore, NCG is a promising, effective and low-cost alternative to rumen-protected arginine in ruminants.