Association between Weaning Stress and Rumen Microbiota in Goat Kids: Evidence from Granger Causality and Randomized Controlled Trial Validation

Weaning stress is frequently associated with disrupted gastrointestinal microbiota and decreased growth performance, the association between them remains unclear. In this study, we employed Granger causality inference to compare the dynamic changes in gastrointestinal microbiota between stressed and non-stressed goat kids, followed by validation through a randomized controlled trial involving rumen microbiota transplantation. Our findings indicated that the alpha diversity and microbial maturity of the rumen microbiota in stressed kids were significantly lower than those in non-stressed kids during the weaning period (p<0.05). Furthermore, the rumen microbiota at pre-weaning could accurately predict the body weight changes during weaning stress period (R2=0.99, RMSPE=0.19). We demonstrated that the cultured rumen microbiota retained most high-abundance rumen bacteria (89.22%), and its transplantation effectively altered the rumen microbiota (ANOSIM, p<0.05), enhanced microbial maturity (p<0.05), and improved growth performance (p<0.05) during weaning, without affecting the gut microbiota (p>0.05). Additionally, transplantation of the cultured rumen microbiota reduced intestinal permeability and inflammation while increasing antioxidant levels in weaned kids(p<0.05). These findings provide evidence for the association between rumen microbiota and weaning stress, demonstrating that manipulating rumen microbiota is an effective strategy for alleviating weaning stress in goat kids.