SOME STUDIES ON USE OF YEAST (SACCHAROMYCES CREVICE) TO REDUCE AFLATOXIN B1IN OREOCHROMIS NILOTICUS
Nadia A. Abd El-Ghany1; Mohamed Fahmy Abou El Azab2; M. Barakat3 and Sabreen E. Fadl3
1Dept. of Fish Diseases, Animal Health Research Institute, Dokki, Giza, Egypt.
2Dep. of Clinical Pathology, Faculty of Veterinary Medicine, Kafr El Sheikh University, Egypt.
3Dep. of Biochemistry, Animal Health Research Institute – kafrelshikh, Egypt.
|Received 1/ 12/ 2013||
Accepted 18/ 1/ 2014
One hundred samples of fish rations were collected and subjected to mycological and toxicologically examination. The results showed that four genera of mould, the most commonly isolated mould species were Aspergillus spp (80%), Alternaria spp. (60%), Penicillium spp. (50%) and Cladosporium spp (30%). Eighty Aspergillus isolates belonged to the five species including A. flavus (75%), A. ochraceus (50%), A. niger (37.5%), A. clavatus (25%) and A. fumigatus (12.5%). Moulds of A. flavus that isolated from fish rations were able to produce aflatoxins on crushed corn media. 30 isolates of A. flavus out of sixty isolates (50%) were AFB1 producers in the range of (10 to 400 ppb). AFB1 intoxicated fish showed sluggish swimming, off food, loss of reflexes, increased opercular movements, darkness of the skin and the presence of excessive amounts of mucus on gills. Internally, liver displayed pale coloration with patches of congestion and pin point hemorrhages. The gall bladder was distended with brownish bile. The spleen and the Kidneys appeared enlarged, congested and dark in color.
Effect of the Saccharomyces cerevisiae (S. cerevisiae) on survivability, total weight gain and some hemato-biochemical parameters as well as organ residues of AFB1 in Nile tilapia fish fed on AFB1-contaminated diet were investigated. The fish were fed diets containing 0 or 200 ppb AFB1 and 0, 1, or 2 gm of S.cerevisiae/ kg diet in a 2 × 3 factorial arrangement of treatments. After 12 weeks; blood, liver and muscle samples were collected from all fish. The result showed that the total weight gain and survival rate were significantly decreased in fish fed AFB1- contaminated diet (p<0.05), while fish fed diets supplemented with S. cerevisiae and contaminated with AFB1 showed no significant change in the total weight gain and survival rate compared with negative control group (p>0.05). Also, there was a significant decrease in red blood cell (RBCs) count, packed cell volume (PCV), hemoglobin (Hb), and white blood cell (WBC) count in fish fed AFB1 contaminated diet (p<0.05). However, fish fed diet supplemented with S. cerevisiae and contaminated with AFB1 showed non significant decrease in RBCs, PCV, Hb and WBCs count compared to those fed standard basal diet only. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were significantly increased in fish fed AFB1-contaminated diet compared to those fed standard basal diet only (p<0.05). But, fish fed diet supplemented with S. cerevisiae at a rate of 1 gm/kg diet and contaminated with AFB1 showed a significant decrease in AST and ALT activities compared to those fed diet contaminated with AFB1 only. Total protein, albumin, and globulin concentrations were significantly decreased in fish fed AFB1-contaminated diet (p<0.05). However, S. cerevisiae supplementations minimize this negative effect of AFB1 on their concentrations. Also, Urea and creatinine concentrations were significantly increased in fish fed the AFB1-contaminated diet (p<0.05). But, S. cerevisiae supplementation counteracted the negative effect of AFB1 on their concentrations. Furthermore, AFB1 residues were not detected in liver and muscle of fish supplemented with S. cerevisiae at rate of 1 gm/kg diet in comparison with fish fed AFB1-contaminated diet only.
In conclusion, dietary supplementation of S. cerevisiae may protect against the toxic effect of AFB1 in Nile tilapia.
Key words: Saccharomyces cerevisiae, Aflatoxin B1, Toxicity, Nile tilapia.