Effects of Dietary Bacillus subtilis and Bacteriophage Supplementation on Water Quality, Carcass Traits, and Muscle Growth in Magang Geese.

BACKGROUND: Escherichia coli and Salmonella contamination in goose bath water releases endotoxins like lipopolysaccharide (LPS), compromising immunity and hindering goose farming. OBJECTIVE: This study evaluated effects of dietary Bacillus subtilis and bacteriophage supplementation on water quality, carcass traits, and muscle growth in Magang geese. METHOD: A total of 288 geese were divided into four groups based on similarity in weight (n = 6 geese): A (basal diet); B (basal diet + bacteriophage: 5.0 × 10(10) PFU/L at 1:1000 dilution); C (basal diet + Bacillus subtilis: 5.0 × 10(9) CFU/kg); D (basal diet + bacteriophage + Bacillus subtilis). RESULTS: Supplementation significantly increased wing length, tibia length, and live weight at 60 days. It reduced water and plasma endotoxin levels and suppressed viable counts of Escherichia coli, Salmonella, and total bacteria in water across rearing stages. Supplementation up-regulated mRNA and protein expression of myogenic regulators (MYOD, MYOG, MYH1) and IGF-1, while down-regulating pro-inflammatory cytokines (TNF-α, IL-6), suggesting enhanced myofiber growth. CONCLUSION: These findings demonstrate that Bacillus subtilis and bacteriophage supplementation improves goose growth performance and immune status by modulating key genes, reducing pathogens and endotoxins, offering an eco-friendly strategy to enhance productivity and potentially reduce antibiotic dependency.