Impact of Bambusa vulgaris-supplemented diet on Nile tilapia challenged with Pseudomonas putida: Hematological, immune, and oxidative responses

Abstract

This study investigated the effects of bamboo shoot extract (Bambusa vulgaris) as a feed additive on the health profiles and infection resistance of Nile tilapia (Oreochromis niloticus) against Pseudomonas putida. Bamboo shoot extract was added at levels of 0 g, 40 g, and 60 g per 1000 g of diet over a 60-day period. The fish were then challenged with a pathogenic P. putida strain. Chemical analysis of the bamboo shoot extract identified 3,5-dinitrophenol and hydroquinone as the two most abundant compounds. Results showed that fish fed bamboo-enriched diets exhibited significantly enhanced levels of red blood cells, hemoglobin, hematocrit, white blood cells, and platelets, and improved erythrocyte cellular and nuclear morphologies, indicating improved health profiles after the challenge. Liver function indicators, including AST, ALT, and ALP, were notably balanced in fish receiving bamboo shoot extract post-challenge (p < 0.05). Blood levels of K⁺ were lower in the bamboo-fed groups. Additionally, blood levels of Ca⁺⁺ and Na⁺ were reduced in fish fed 40 g and 60 g of bamboo, respectively, compared to the control group (p < 0.01). The bamboo extract also enhanced immune and oxidative capacities, as demonstrated by increased catalase, superoxide dismutase, lysozyme activity, and phagocytic activity, along with reduced malondialdehyde levels and elevated serum immunoglobulin M (p < 0.01). Gene expression analysis revealed significant effects of Bambusa vulgaris extract, Pseudomonas infection, and their interaction on the expression of interleukin-1β, interleukin-10, and NK-lysin genes, with varying expression levels at 1, 3, and 7 days post-challenge (p < 0.05). The liver bacterial load in fish exposed to P. putida significantly decreased in the bamboo-fed groups, with the lowest count observed in the 60 g bamboo group. Additionally, survival rates were markedly higher in the bamboo-fed groups compared to the control, with no significant difference between the two bamboo-fed groups. In conclusion, dietary supplementation with bamboo shoot extract enhances hematological parameters, blood cell and nuclear morphology, and increases survival rates in Nile tilapia following infection.