Goat-derived Lactobacillus amylovorus improved floppy kid syndrome via regulating gut microflora

Floppy Kid Syndrome (FKS) severely restricts goat farming due to high mortality from metabolic disturbances and gut dysbiosis. Here, we aimed to isolate a goat-derived probiotic and evaluate its capacity to restore gut homeostasis in FKSaffected goats. Lactobacillus amylovorus isolates was obtained via selective colony morphology, Gramstain and catalase testing, and confirmed by 16 S rRNA sequencing (≥ 98% identity). The isolate survived at pH 2.0 (72%) and pH 3.0 (85%), tolerated 0.3% bile salts (survival > 10%), and retained > 40% viability after 60 s at 60 °C. In disk diffusion assays, inhibition zones averaged 16 mm against Escherichia coli and 12 mm against Staphylococcus aureus. In FKSaffected goats receiving 1 × 108 CFU/day for 3 days, Shannon diversity increased by 25% (p < 0.05), Simpson index by 18% (p < 0.05), and shared species with healthy controls rose from 8 to 17. Relative abundance of EscherichiaShigella declined by 40%, while Lactobacillus and Ruminococcus increased by 30% and 22%, respectively (p < 0.05). Goat-derived L. amylovorus displays robust acid, bile and heat tolerance, inhibits key pathogens, and effectively regulates gut microbiota in FKSaffected goats. These findings support its promise as a novel probiotic intervention for preventing and treating Floppy Kid Syndrome.