Evaluation of Viligen® NE as a feed additive for pacific white shrimp reared in a biofloc system during the nursery phase

The aim of this study was to evaluate Viligen® NE (Alltech®, USA) as a feed additive for Penaeus vannamei reared in a biofloc system during the nursery phase, focusing on growth performance, intestinal microbiological analysis, and resistance to thermal shock. Shrimp post-larvae (41 mg) were fed for six weeks with four experimental diets: (a) 0.5 g Viligen® NE kg⁻¹; (b) 1 g Viligen® NE kg⁻¹; (c) 2 g Viligen® NE kg⁻¹; and (d) a control diet (0 g Viligen® NE kg⁻¹). The experiment was conducted in quadruplicate, totaling 16 experimental tanks, with a stocking density of 2000 post-larvae m⁻³. Shrimp growth performance parameters were positively influenced by the inclusion of Viligen® NE in the diet. Polynomial regression indicated an optimal inclusion level of 1.17 g kg⁻¹ for maximizing specific growth rate and weight gain. Additionally, supplementation at 1 g kg⁻¹ enhanced shrimp resistance to thermal shock. However, no significant differences were observed in intestinal counts of total heterotrophic bacteria or Vibrio spp. among treatments. In conclusion, dietary supplementation with Viligen® NE at an optimal level of 1.17 g kg⁻¹ improved growth performance, and 1 g kg⁻¹ enhanced thermal shock resistance of nursery-phase shrimp reared in a biofloc system.