Effects of fermented Chinese herbal medicines on lamb growth performance, rumen fermentation parameters and apparent digestibility of nutrients

Objective This study aimed to investigate the effects of fermented compound Chinese herbal medicines on growth performance, rumen fermentation parameters, and apparent nutrient digestibility in Hu lambs.

Methods A total of 120 Hu lambs, aged 15 days with similar birth weight (3.25 ± 0.50) kg and good body condition, were randomly divided into four groups (each group had three replicates of 10 lambs, half male and half female), and fed respectively with lamb starter (control group), starter + 0.2% fermented Chinese herbal medicine (0.2% group), starter + 0.4% fermented herbal medicine (0.4% group), and starter + 0.6% fermented herbal medicine (0.6% group) for 45 days.

Results (1) Different levels of fermented herbal medicine did not significantly affect average daily gain (P>0.05); however, compared with the control group, the final body weight of lambs in the 0.2% and 0.6% groups was significantly increased (P<0.05). (2) No significant differences were observed among groups in ruminal concentrations of acetic acid, propionic acid, butyric acid, isovaleric acid, valeric acid, lactic acid, total volatile fatty acids, rumen pH, or ammonia nitrogen (NH₃-N) (P>0.05); compared with the control group, the 0.6% group showed significantly higher isobutyric acid content and acetate-to-propionate ratio (P<0.05). (3) The apparent digestibility of ether extract was significantly higher in the 0.6% group than in the control group (P<0.05); compared with the 0.4% group, the apparent digestibility of neutral detergent fiber was significantly lower in the control group (P<0.01) and the 0.6% group (P<0.01), and in the 0.2% group (P<0.05); the apparent digestibility of gross energy in the control and 0.4% groups was significantly higher than that in the 0.2% group (P<0.05); the apparent digestibility of calcium (Ca) and phosphorus (P) in the control and 0.2% groups was significantly lower than that in the 0.4% group (P<0.05).

Conclusion In conclusion, under the conditions of this experiment, adding fermented Chinese herbal medicines to the diet of Hu lambs improved growth performance and apparent nutrient digestibility, enhanced feed utilization efficiency, supplemented animal nutrition, and promoted rumen development.