Effects of aflatoxin B1on growth performance, blood components, immune function and histopathological changes in black tiger shrimp (Penaeus monodonFabricius)

Aflatoxin B1 was studied in juvenile black tiger shrimp (Penaeus monodon Fabricius) (1–2 g) to see the effects on growth performance and histopathology, and in adult shrimp (10–12 g) to study the effects on immuno-physiological function, histopathology and aflatoxin residue. Feeds supplemented with 0, 50, 100, 500, 1000 and 2500 p.p.b. aflatoxin B1 were given to test groups for an 8-week period. Aflatoxin B1 in the diet showed highly negative correlation to average weight, weight gain and survival (r = − 0.99, −0.96 and −0.95 at P < 0.05, respectively). Aflatoxin B1 at 50–100 p.p.b. produced no effect on growth in juvenile shrimps; however, growth was reduced when aflatoxin B1 concentrations were elevated to 500–2500 p.p.b. Survival dropped to 26.32% when 2500 p.p.b. aflatoxin B1 was given, whereas concentrations of 50–1000 p.p.b. had no effect on survival. Total haemocyte count and phenoloxidase activity increased by the fourth week in shrimp receiving the highest concentration of aflatoxin B1 and gradually declined from the sixth to eighth week. Alkaline phosphatase and cholesterol in serum have no correlation to aflatoxin in the diet after 4 weeks of the feeding but have a high correlation after 6 weeks of feeding. Calcium and phosphorus levels in the blood have no correlation with the aflatoxin concentration in diet. There were marked histological changes in the hepatopancreas of shrimp fed diet containing aflatoxin B1 at a concentration of 100–2500 p.p.b. for 8 weeks, as noted by atrophic changes, followed by necrosis of the tubular epithelial cells. Severe degeneration of hepatopancreatic tubules was common in shrimp fed high concentrations of aflatoxin B1. Infiltration of connective tissue into interstitial tissue of the hepatopancreas, as well as encapsulation of necrotic tissue/cells, was also observed. The residue detected in muscle was higher than in the head and shell after 4 weeks of feeding. After 6 weeks, the residue found in muscle was very low and the residue found in the mixture of head and shell decreased compared to the 4-week sample.