The use of antibiotics in animal diets is facing negative feedback due to the hidden danger of drug residues to human health. Traditional Chinese herbal medicine has been used to replace antibiotics in the past two decades and played an increasingly important role in livestock production. The present study was carried out to assess the feeding effects of a traditional nourishing Chinese herbal medicine mixture on kinetics of plasma glucose, protein and energy metabolism in sheep. Ruminal fermentation characteristics were also determined.

The aim of this study was to evaluate the effect of feeding decoction of a traditional nourishing Chinese herbal medicine formula on rates of plasma phenylalanine and tyrosine turnover and whole body protein synthesis in sheep. Ruminal fermentation characteristics and blood metabolites were also determined. Six sheep were subjected to either mixed hay (MH‐diet, as control) or MH‐diet supplemented with 2% of Chinese herbal medicine (mixture of Astragalus root, Angelica root, and Atractylodes rhizome; CHM‐diet) in a crossover design for each of 3‐week period. The isotope dilution of [²H₅]phenylalanine and [²H₂]tyrosine was performed as a primed‐continuous infusion to measure plasma phenylalanine and tyrosine kinetics. Concentrations of total volatile fatty acid, acetate, and propionate in the rumen tended to be higher (p < 0.10), and the pH value was lower (p = 0.04) for the CHM‐diet than the MH‐diet. Turnover rates of plasma phenylalanine and tyrosine tended to be higher (p < 0.10) for the CHM‐diet than the MH‐diet. Furthermore, whole body protein synthesis was greater (p = 0.04) for the CHM‐diet compared with the MH‐diet. The Chinese herbal medicine improved rumen fermentation and enhanced protein metabolism in sheep. Hence, it is suggested that the decoction of Chinese herbal medicine formula could be considered as a potential feed additive for ruminant production.

Traditional Chinese medicine (TCM) encompasses a wide range of natural herbs and plants that are used to treat or prevent diseases or promote health. This study aimed to evaluate the effect of feeding a TCM formula extract on nitrogen (N) balance, microbial nitrogen supply (MNS), and plasma leucine kinetics in sheep. Six sheep were fed with mixed hay (Hay-diet) only or supplemented with 2% TCM (mixture of Astragalus root, Angelica root, and Atractylodes rhizome; TCM-diet) in a crossover design over two 21-day periods. An isotope dilution of [1-¹³C]leucine was used to measure the rate of plasma leucine turnover. Purine derivative (PD) excretion in urine was determined to estimate the MNS. The TCM-diet significantly increased N intake (p < 0.01) and N digestibility (p = 0.02) compared to the Hay-diet, with less N excretion (p = 0.02) in feces, while no significant difference was observed between diets in terms of N excretion in urine and N retention. Total PD excretion and MNS were higher (p < 0.01), as well as the turnover rate of plasma leucine tended to be higher (p = 0.06) with the supplementation of TCM. The present results suggested that the TCM formula could be considered as a potential feed additive for ruminant production.