Trial for reduction of Ochratoxin A residues in fish feed by using nano particles of hydrated sodium aluminum silicates (NPsHSCAS) and copper oxide.

This paper was designed to analyze the effect of ochratoxin A (OTA) contaminated feed on the growth outcomes, certain serum biochemical, histopathology, and OTA residue in the dorsal muscle, liver, and kidney in Nile tilapia. Also, to improve the drastic effect of OTA through dietary supplementation of hydrated sodium aluminum silicates nanoparticles or nano copper. For performing the present study, 270 fish were randomly allotted into 6 equal groups according to ochratoxin and nanoparticles of hydrated sodium aluminum silicates or copper oxide. The results indicated that supplementation of two levels of both nanoparticles (aluminum silicate or copper) as a mycotoxin adsorbent could prevent ochratoxicosis in Nile tilapia fish. In addition, they maintained optimal growth performance, feed efficiency without bad effect on serum profiles and vital organs function of fish in a dose-dependent manner. Histopathologically, the most interesting finding was the precipitation of calcium salts known as nephrocalcinosis, within the tubules, upon the degenerative tubules and tunica intima and media of the blood vessels in the control positive group. These pathological lesions were mitigated by nanoparticle supplementation. Thus increase the safety of fish products.

Effect of phytase enzyme on growth performance, serum biochemical alteration, immune response and gene expression in Nile tilapia.

The present study aimed to investigate the effect of low phosphorus diet with or without different levels of phytase enzyme supplementation on growth performance, body composition, nutrient retention efficiency, gene expression, and health status of A. hydrophila challenged fish. A total of 240 monosex males of Nile tilapia (Oreochromis niloticus) with an average body weight of 23.19 ±â€¯0.15 g/fish were used. Fish were randomly chosen and divided into 4 equal groups (60 fish per group), with 3 subgroups containing 20 fish as a replicate. Group 1, was fed on a diet containing 100% P, group 2, was fed on a diet containing 50% P, group 3 and 4, were fed on low P with 500 or 1000 units of phytase/Kg respectively. It was observed that the 50% phosphorus diet significantly reduced body weight, feed intake, feed conversion ratio (FCR), and protein efficiency ratio (PER) compared to Nile tilapia fish fed on the diet containing 100% phosphorus. In contrast, fish fed on the diet containing 50% phosphorus supplemented by 500 or 1000 phytase units/kg significantly (P ≤ 0.05) increased final body weight (FBW), total body gain (TBG), average daily gain (ADG), and weight gain compared to Nile tilapia fed on the same diet or fed on the diet containing normal phosphorus without phytase supplementation. Different phosphorus and phytase supplementation levels had no significant effect on serum total protein, albumin, and globulin concentrations, meanwhile, phytase supplementation increased serum calcium and phosphorus levels. Nile tilapia fed on phytase supplementation had an increase in body protein, lipid content, and nutrient utilization efficiency compared to Nile tilapia fed on the diet containing 100% phosphorus. Nile tilapia fed on low dietary phosphorus showed an increase in mortality after infection and a decrease in phagocytosis and neutrophil compared to fish fed on normal phosphorus. Phytase supplementation, made immune response parameters return to its normal values and the pathological lesions of liver, spleen, stomach, and intestine were reduced. Moreover, normal phosphorus significantly up-regulated lipoprotein lipase (LPL) mRNA expression and down-regulated fatty acid synthase (FAS) mRNA in Nile tilapia's liver while low phosphorus with or without phytase supplementation reduced LPL expression and relatively up-regulated FAS.