Oral Probiotics Modulate the Gut Microbiome, Nutrient Transport Gene Expression, and Growth of Hybrid Tilapia (Oreochromis sp.) Fed with Black Soldier Fly (Hermetia illucens)

Maggot Black Soldier Fly (BSF) is a nutritionally rich alternative food for fish. Still, due to its slow digestion, it must be combined with other technologies to produce fish with excellent growth. This study aims to determine the effect of the probiotic application on the growth, microbiome, and gene expression in the intestines of tilapia-fed maggots BSF. Tilapia intestines were examined after two months of rearing with three replications and two treatments: A) 30% maggots and 70% commercial pellets with probiotics and B) 30% maggots and 70% commercial pellets without probiotics. We discovered that probiotics significantly positively impact the fish gut microbiomes and absolute growth. The amplicon sequence variant in the probiotic treatment (A) was 25 with dominance by Cetobacterium, Acinetobacter, Enhydrobacter, and Gemmobacter, while the non-probiotic treatment (B) was 8 with dominance of Cetobacterium and Turicibacter. The probiotic treatment raised the expression of Ghrelin, Muc-2, IL-1β, and I-FABP genes but not the CD-36 gene. These findings suggest oral probiotics can help boost tilapia production when fed maggot black soldier fly (Hermetia illucens).