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

Objective: Weaning stress is frequently associated with disrupted gastrointestinal microbiota and decreased growth performance, the association between them remains unclear.

Methods: 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.

Results: 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).

Conclusion: 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.