Dietary intervention of propolis and/or turmeric boosted growth, hematology, biochemical profile, and antioxidant-immune responses and their associated gene expression in Nile tilapia (Oreochromis niloticus) challenged with Edwardsiella tarda

Immunostimulant phytogenic feed additives are given great concern for improving fish health, growth, immune responses, and resistance to diseases. This research investigated the impact of dietary propolis (PRO), turmeric (TUR), and their combination on the growth, hematology, antioxidant-immune responses, and their regulating genes in Nile tilapia ( Oreochromis niloticus ) during Edwardsiella tarda challenge. For 8 weeks, a total number of 320 fish (20.70 ± 0.14 g) were allocated into four groups at random, each with eight replicates (10 fish each). The first group (1st) was given the basal diet (control) without any supplements. The 2nd, 3rd, and 4th groups were supplemented with 1% PRO, 1% TUR, and the mixture (1%PRO + 1%TUR), respectively. The experimental groups were challenged intraperitoneally with E. tarda at a dose of 0.1 mL (1 × 10 5 CFU) at the termination of the feeding trial, and the fish survival was estimated for an additional 7 days. The results demonstrated that fish-fed diets supplemented with PRO and/or TUR showed higher body weight, condition factor, specific growth rate, feed intake, and feed efficiency utilization than the control group ( P