Nano-selenium supplementation: improving growth, digestibility and mineral absorption in freshwater fish, Catla catla.

Background: This research investigated the impact of selenium-nanoparticles (Se-NPs) supplemented in sunflower meal (SM)-based diets on digestibility, mineral absorption, and growth performance of Catla catla. Se-NPs were added to seven test meals in varying amounts (0, 0.5, 1, 1.5, 2, 2.5 and 3 mgkg^- 1). A total of 315 fish were evenly allocated three replicate tanks, with 15 fish per tank, and given diets equivalent to (5%) of their wet biomass daily for a period of 90 days.

Results: The test diet (T-D) supplemented with 1.5 mgkg^- 1 Se-NPs yielded remarkable results, including a significant increase in mean weight gain (14 g), an impressive average weight gain percentage (208%), a 100% survival rate, with no mortality observed and the highest specific growth rate (1.25). Moreover, 1.5 mgkg^- 1 Se-NPs (T-D-IV) demonstrated superior nutritional digestibility (CP, 76%; CF, 79% and GE, 74%). Additionally, the diet 1.5 mgkg^- 1 Se-NPs showed enhanced mineral absorption (K, P, Ca, Na, Zn, Cu and Fe) than other diets.

Conclusion: It was practically proven that the growth indices, nutrient absorption, and mineral status of C. catla were significantly improved by Se-NPs supplemented SM-based diets, with the optimum level of supplementation being 1.5 mgkg^- 1.