Effects of dietary supplementation of Bacillus subtilis and bacteriophage on water quality, carcass traits and muscle growth of Magang Geese

Presence of Escherichia coli and Salmonella causes poor bath water quality, which is an important factor plaguing the development of the goose farming industry. As these bacteria release stable endotoxins like Lipopolysaccharide (LPS), which can affects goose farming by impairing their immune health. Bacillus subtilis is a non-toxic Gram-positive probiotic that can decompose organic matter in water, improves feed efficiency in animals, inhibit harmful bacteria, and enhances the animal growth. Bacteriophages are virus which can specifically kill bacteria, reduce their numbers in the environment. To evaluate the effects of dietary supplementation of Bacillus subtilis and bacteriophage on Magang geese's carcass traits, skeletal muscle weight percentage, myogenic gene and immunity factor gene mRNA expression during different rearing stages, 288 one-day old Magang geese were divied into 4 groups with with 6 replicates. The dietary treatments were group A, basal diet (with no treatment), group B, basal diet with 5.0×10 ¹⁰ PFU/L bacteriophage at a concentration of 1/10 ³ , group C, basal diet with 5.0×10 ⁹ CFU/kg Bacillus subtilis and group D, basal diet with bacteriophage and Bacillus subtilis in combination same as group B and C. The results indicated that dietary supplementation of Bacillus subtilis and bacteriophage or their combination significantly increased wing length, tibia length and live weight on 60 d, reduced the levels of feeding environment water endotoxin as well as blood endotoxin in all stages, and suppressed the levels of Escherichia coli , Salmonella , and total bacterial colony in the water. It may also play a role in promoting muscle production through the mRNA and protein expression of muscle-associated factors ( MYOD , MYOG , MYH1 ), insulin like growth factor ( IGF-1 ) and reducing the mRNA and protein expression of inflammatory factors ( TNF-α , IL-6 ), which may promote the growth of myofiber diameter and improve growth performance. These findings may guide new strategies to improve goose productivity and immunity, provide new eco-friendly methods to manage farming environments and thereby reducing the use of antibiotics.