The use of synthesized stabilized nanoparticles of selenium as a feed additive in shrimp Litopenaeus vannamei diets: Performance, antibacterial activity, gut microbiota and immune-related genes expression

The shrimp aquaculture industry faces challenges that hinder production, including pathogens and infections from bacteria-causing diseases. The present study aimed to examine the impact of dietary synthesized chitosan stabilized selenium nanoparticles (CSSeNPs) on the growth performance of gut microbiota and immune-associated genes for shrimp L. vannamei aquaculture. The experiments were accomplished for 12 weeks in triplicate fiberglass circular tanks (200 L). A 300 shrimp post-larvae (PL) weighing an average of 0.14 ± 0.001 g was utilized. Four experimental groups were assigned to 12 tanks. Each tank contained 25 PL. Each group fed with one of the following diets: control (C), commercial diet without CSSeNPs (Control; T1), 25 mg/kg CSSeNPs (T2), 35 mg/kg CSSeNPs (T3), and 45 mg/kg CSSeNPs (T4). The specific growth rate (SGR) and feed conversion ratio (FCR) showed improvement (P ≤ 0.05) in the T2 and T3 groups compared to the control group. The relative expression of all examined genes LPS/b-glucan binding protein, glutathione peroxidase and superoxide dismutase (L-GBP, GPX, and SOD) were increased (P < 0.05) at T3. CSSeNPs demonstrated anti-fish pathogen efficacy against Gram-positive and Gram-negative bacteria. The Enterococcus faecalis bacterium displayed the highest vulnerability to inhibition. In contrast, Escherichia coli exhibited the lowest level of susceptibility. Moreover, a quantitative assessment of the prebiotic-like effect of CSSeNPs on shrimp gut showed increased lactic acid bacteria. Also, no Vibrio sp., Salmonella sp., Shigella sp., or Pseudomonas sp. were detected in the T3 group feed on 35 mg/Kg CSSeNPs. This work provides a new safe additive that is eco-friendly for the shrimp diet and improves growth, immunity, and disease control.