Co‐Supplementation of Vitamins C and E Ameliorates Growth, Blood Biochemistry, Histomorphometry and Mucosal Health in Nile Tilapia, <i>Oreochromis niloticus</i> Under High Stocking Density

ABSTRACT Supplementing diets with vitamins C and E has been reported to reduce the negative effects of stress associated with higher stocking density. This study investigated the combined effects of dietary vitamins C and E on the growth, nutritional composition, haematobiochemical response and mucosal health of Nile tilapia, Oreochromis niloticus . Juvenile Nile tilapia, with an initial weight of 2.53 ± 0.02 g and length of 37.2 ± 0.7 mm, were randomly distributed into nine tanks having a higher stocking density of 30 individuals per tank (50 L water capacity). The fish were fed for 56 days with three experimental diets: CTR (vitamin C: 0 mg/kg, vitamin E: 0 mg/kg), VC200E100 (vitamin C: 200 mg/kg, vitamin E: 100 mg/kg) and VC400E200 (vitamin C: 400 mg/kg, vitamin E: 200 mg/kg). Fish fed the VC400E200 diet showed significantly higher final body weight, weight gain, percentage weight gain, specific growth rate, protein efficiency ratio, survival and condition factor, along with a lower feed conversion ratio compared to the CTR group. Fish administered VC400E200 also exhibited significantly elevated haematobiochemical parameters, particularly haemoglobin, red blood cells, packed cell volume, mean corpuscular volume and mean corpuscular haemoglobin compared to the CTR ( p &lt; 0.05). Erythrocytic cellular and nuclear abnormalities significantly decreased with the enhancement of vitamins C and E. Fish treated with dietary VC400E200 displayed improved gill and gut morphology when compared to the CTR. Principal component analysis (PCA) and Pearson's correlation demonstrated a positive correlation between condition factor and ‘PC1 intestinal and gill health’ and ‘PC1 blood variables’ of VC400E200 fed fish when compared to the CTR. The findings of this study recommend the supplementation of vitamins C and E in feed to enhance growth, feed utilization and overall health improvement in Nile tilapia.