Exploring the effect of dietary nano selenium and/or Vitamin E and their interplay on reproductive physiology of Nile tilapia broodstock: Insights into spawning performance, haemato-biochemical profile, gene expression and gonadal architecture.

Abstract

This research was conducted to explore the dietary effects of selenium nanoparticles (NSe), Vitamin E (VE) and their mixture supplementation on reproduction capacity, haemato-biochemical responses, spawning performance, gene expression and gonadal histology of Nile tilapia ( Oreochromis. niloticus ) broodstock. Fish brooders were allocated into four treatments in triplicates and served the formulated diets: basal diet (Control, G 0 ), 1 mg NSe kg −1 (G 1 ),100 mg VE kg −1 (G 2 ) and an inclusion of 1 mg NSe kg −1 + 100 mg VE kg −1 (G 3 ). Diets were fed to Nile tilapia (215 ± 34.56 g) stocked at a male: female ratio of 1: 3 for 60 days. The results revealed that hematological parameters (RBCs, WBCs, PCV, Hb), total protein, globulin and albumin were significantly increased ( P < 0.05 ) in fish group fed dietary combination of 1 mg NSe kg −1 + 100 mg VE kg −1 . While other indices (MCV, MCH, MCHC) remained unaffected among the different treated groups ( P > 0.05). Optimum liver function enzyme activity and the highest reproductive hormones (MT, FSH, LH and progesterone) concentrations were found in the dietary inclusion of 1 mg NSe kg −1 + 100 mg VE kg −1 . Organo-somatic indices, egg diameter and expression of reproductive genes ( vasa , nanos1a, nanos2, dnd1, pum1, amh and VTG ) are boosted ( P < 0.05 ) in 1 mg NSe kg −1 + 100 mg VE kg −1 showing that this blend is required for the optimal reproductive capacity. Reproductive performance (mean fry number per female and mean fry weight) increased and gonadal architecture were improved in NSe-supplemented groups, with the highest recorded level in fish fed NSe/VE blend. In conclusion, our results revealed that dietary supplementation with 1 mg NSe kg −1 and/or 100 mg VE kg −1 can be effectively used for reproductive performance of Nile tilapia. The inclusion of NSe and VE at 1:100 mg/kg incorporated into fish diet seems to have a synergistic effect required for supporting haemato-biochemical indices and enhancing the overall spawning performance of Nile tilapia broodstock by increasing concentrations of sexual hormones, improving egg diameter, boosting gonadal puberty and up-regulating the expression of reproductive-related genes. • Supplementation with 1 mg NSe kg ‐1 and/or 100 mg VE kg ‐1 can be effectively used for reproductive performance of tilapia. • Results showed that 1 mg NSe kg ‐1 + 100 mg VE kg ‐1 is required for the optimal reproductive capacity. • Reproductive indices and gonadal architecture were improved, with the highest recorded level in fish fed NSe/VE blend. • NSe/VE improved haemato-biochemical indices and the overall spawning performance of Nile tilapia broodstock.