Growth performance, antioxidant status, intestinal morphology, and body composition of Nile tilapia (Oreochromis niloticus) supplemented with essential oils: A meta-analysis

This study aimed to evaluate the effects of dietary supplementation with essential oils (EOS) on growth performance, antioxidant status in blood serum, intestinal morphology, and whole-body composition of Nile tilapia (Oreochromis niloticus) through a meta-analytic approach. The search and collection of scientific articles were conducted using the PRISMA methodology, and 45 full-text scientific articles were obtained. The data used in the meta-analysis were extracted from these 45 documents. The effect size was assessed through weighted mean differences (WMD) using Der-Simonian and Laird random effects models. Dietary supplementation with EOS increased (P < 0.001) final weight, body weight gain, specific growth rate, feed intake, protein efficiency ratio, and survival but decreased (P < 0.001) feed conversion ratio. In blood serum, EOS supplementation decreased (P < 0.001) the concentration of malondialdehyde and increased (P < 0.001) the concentration of catalase, superoxide dismutase, and glutathione peroxidase. In the foregut, midgut, and hindgut, greater (P < 0.01) villus height, villus width, and number of goblet cells were observed in response to EOS supplementation. EOS supplementation increased (P < 0.01) crude protein content and decreased (P < 0.05) crude lipid content in the whole-body. In conclusion, essential oils can be used as a dietary additive to improve growth performance, antioxidant status in blood serum, and intestinal morphology in Nile tilapia. Likewise, supplementation with essential oils increases the protein content and decreases the fat content in the whole-body of Nile tilapia.