Vitex Agnus-Castus Extract Supplementation Enhanced Growth Performance, Hemato-Biochemical Parameters, Intestinal...

Plant-derived extracts offer a promising alternative to synthetic additives in fish feed, with the aim of enhancing growth, health, and sustainable production. The present study aimed to evaluate the effect of the hydroalcoholic extract of dietary Chaste tree, Vitex agnus-castus (VAC), on growth performance, feed utilization, digestive enzymes, hematological, serum biochemical parameters, intestinal histomorphometry, and flesh composition and quality of Nile tilapia, Oreochromis niloticus. A total of 160 Nile tilapia fingerlings were allocated in five equal treatments and fed increasing levels of VAC extract (0, 5, 10, 15, and 20 g/kg of diet) and referred as control, VAC₅, VAC₁₀, VAC₁₅, and VAC₂₀, respectively, for 8 weeks. Fish in the VAC₅ group achieved the highest growth performance, digestive enzyme activities, and significantly improved feed conversion ratio (FCR) and protein efficiency ratio (PER). The predicted maximum VAC level supplementation was 9.81 g kg^-1 diet as determined by quadratic regression based on growth and feed utilization. The hematological parameters increased significantly in the VAC_{5 and 10} groups. Liver function enzymes, glucose (GLU), triglycerides (TGs), and creatinine were significantly decreased, while total protein (TP) and albumin (ALB) were significantly increased in fish fed VAC₅ and VAC₁₀ diets. However, total cholesterol (TCH) was significantly increased with VAC supplementation on a level-dependent basis. Histometric investigation of the intestinal tract revealed a significant improvement in muscular and submucosal thickness, villi length, and width. The chemical composition of the muscle revealed an improvement in protein and dry matter in the VAC₅ group, with decreased water loss during storage, dripping, and freezing. In conclusion, VAC extract can be used as a feed additive in the Nile tilapia diet at levels of 5-10 g kg^-1 diet with a positive response in growth, physiological response, and histological architecture.