Improving reproductive performance and larvae survival by dietary administration of probiotic Bacillus cereus NP5 in female African catfish Clarias gariepinus

Probiotic administration has the ability to increase broodstock performance and aquaculture productivity. The effect of dietary probiotics Bacillus cereus NP5 on the reproductive performance of female Clarias gariepinus and the survival of the resulting larvae was investigated in this study. Female fish with an initial weight of 553 ± 27.41 g, were placed in 12 hapas and fed for 12 weeks on three experimental diets supplemented with different concentrations of probiotics: 0 (control), 10⁶ (B6), and 10⁸ CFU g^-1 feed (B8). This study found that B8 fish had higher protein retention (p<0.05), but body weight was comparable among treatments (p>0.05). Furthermore, probiotic diets increased digestive enzyme activity (p<0.05) such as amylase, protease, and lipase. Different doses of B. cereus NP5 probiotic significantly (p<0.05) affected intestinal villi height, but it did not increase villi length or intestinal diameter. Throughout the rearing period, the probiotic groups showed higher estradiol levels, and total cholesterol levels (p<0.05), stimulated early ovarian development, leading to higher GSI, HSI, and percentage of developed eggs (p<0.05). When compared to B6 and the control, the B8 treatment resulted in significantly higher fecundity, hatching rate, and larval survival (p<0.05). The results obtained support the hypothesis that probiotics could improve the reproductive performance and larval survival of female C. gariepinus.