Lemongrass oil supplementation: buffalo-derived in vitro screening of ruminal fermentation and in vivo evaluation in growing beetal goats.

The application of essential oils in ruminant diets presents challenges due to variability in their effects based on dose, diet composition and animal physiology. This study aimed to screen different supplementation levels of lemongrass oil (LGO) through in vitro evaluation for subsequent in vivo assessment of its effects on growth, nutrient digestibility and antioxidant status in Beetal goat kids. The in vitro trial used berseem fodder and concentrate mixture (60:40) incubated with LGO at 0, 0.5, 1.0, 1.5, and 2.0% of dry matter (DM) for 24 h. It was observed that LGO supplementation resulted in a quadratic effect on gas production, in vitro organic matter digestibility and metabolizable energy with values increasing up to 1.0% LGO and declining at higher inclusion levels. In contrast, in vitro dry matter digestibility remained unaffected, while partitioning factor and microbial biomass production tended to decrease with LGO supplementation. LGO supplementation shifted rumen fermentation towards greater propionate and lower acetate production. In the in vivo trial, eighteen goat kids (90 ± 5 days old; 6.29 ± 0.39 kg overall mean initial body weight) were fed either a basal diet or a basal diet supplemented with 1% LGO for 90 days. No significant differences were observed in body weight gain, dry matter intake, digestibility or blood biochemistry. However, LGO supplementation tended to improve erythrocytic catalase and superoxide dismutase activities, with a transient increase in skin-fold thickness up to 48 h post-injection. Overall, the observed responses may have been influenced by small sample size, lower weaning body weight and in vitro-in vivo microbial differences, warranting further study.