Beneficial effects of Persian shallot (Allium hirtifolium) extract on growth performance, biochemical, immunological and antioxidant responses of rainbow trout Oncorhynchus mykiss fingerlings

The aim of this study was designed to analyze the effect of Persian shallot (Allium hirtifolium) extract (PSE) on growth performance, biochemical parameters, antioxidant and immunity status of rainbow trout (Oncorhynchus mykiss) fingerlings. The rainbow trout (25.33 ± 0.15 g) were treated with four effective dosages of 0.5, 1, 2, and, 3% PSE in four separated with one control group for 60 days. At the end of experiment, the rainbow trout treated with PSE showed minimum feed conversion ratio (FCR), maximum weight gain (WG) and specific growth rate (SGR). Increased values of total protein, albumin and globulin were observed in PSE-fed fish; meanwhile, aspartate and alanine aminotransferases (AST, ALT) and alkaline phosphatase (ALP) activities as well as triglyceride, cholesterol, glucose, and cortisol levels significantly decreased in animals fed with 1–2% PSE diet. Activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), total immunoglobulin (total Ig), lysozyme activity, alternative complement hemolytic activity (ACH50), and respiratory burst (NBT) significantly (P < 0.05) increased in the PSE, with highest values in the treatments of 1–2% diet. The dietary PSE supplementation significantly (P < 0.05) decreased levels of malondialdehyde (MDA). A maximum significant amount (P < 0.05) in skin mucus was found in 1–3% PSE, while significant enhancement in total Ig and ACH50 were found in 0.5–3% PSE. All parameters analyzed in this study point at the usefulness of employing PSE in aquaculture as growth, antioxidant and immune system promoter. The optimum inclusion level was estimated to range between 1 and 2%. © 2022 Elsevier B.V

Effects of host-associated probiotic Bacillus altitudinis B61-34b on growth performance, immune response and disease resistance of Nile tilapia (Oreochromis niloticus) raised under biofloc system

This investigation was performed to assess the influences of the host-associated probiotic Bacillus altitudinis B61-34b (BAA) on growth, immune response and disease resistance to Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus). Fish (25.50 ± 0.52 g fish−1) were distributed into 15 aquaria (150 litres tank−1) at density of 20 fish tank−1. The fish were fed basal diets with BAA inclusions in different concentrations: 0 (BAA1—Control), 106 (BAA2), 107 (BAA3), 108 (BAA4) and 109 (BAA5) CFU ml−1 for 8 weeks. A completely randomized design with three replications was used. The results indicated that BAA administration generated greater (p < 0.05) skin mucus and peroxidase activities compared to the control, with maximum levels recorded in BAA4 and BAA5. Higher serum immunities, such as serum lysozyme, serum peroxidase, complement, phagocytosis and respiratory burst activities were observed in the BAA4 and BAA5 dietary groups compared to the control, BAA1, BAA2 and BAA3 diets. The relative percentage of survival, growth performance and FCR were also significantly higher (p < 0.05) in the BAA4 and BAA5 groups. In conclusion, dietary supplementation of B. altitudinis at 108 CFU ml−1 can improve Nile tilapia's growth performance, skin mucus and serum immunities, and disease resistance