Incorporation of exogenous <i>Bacillus</i> probiotics into diets containing black soldier fly ( <i>Hermetia illucens</i> ) larval meal for sex-reversed fingerlings of Redbreasted tilapia ( <i>Coptodon rendalli</i> ): effects on growth performance, hepatosomatic, viscerosomatic, and morphometric indices

Abstract

The study evaluated the effects of dietary supplementation with selected exogenous Bacillus probiotic strains on the growth performance and somatic indices of Redbreasted tilapia (Coptodon rendalli) when black soldier fly larvae meal (BSFLM) was used as the sole animal protein source. Four probiotic inoculation levels were tested in triplicate: T0 [0 CFU/kg] as a control, T1 [4 × 1010 CFU/kg] as treatment 1, T2 [8 × 1010 CFU/kg] as treatment 2, and T3 [12 × 1010 CFU/kg] as treatment 3. A total of 120 Coptodon rendalli fingerlings per treatment (initial weight of 4.1 ± 0.10 g) were fed a 42% crude protein BSFLM diet to maximum satiation in 2 m³ concrete water tanks for 72 days. Fish growth, the viscerosomatic index, the hepatosomatic index, and selected morphometric indices were significantly improved in the fish fed diets supplemented with the T2 inoculation level (p < 0.05). The results demonstrate that dietary exogenous Bacillus probiotic supplementation enhances growth efficiency and organosomatic development in Coptodon rendalli fed BSFLM-based diets, highlighting the potential of combining only insect meal with probiotics as a sustainable nutritional strategy for tilapia culture.