TOXICITY OF BACILLUS THURINGIENSIS AGAINST THE HOUSE FLY POPULATION AND THE CHICKENS FED ON CONTAMINATED FOOD

Abstract

The present work dealt with toxicity and histopathological study of -exotoxin of B. thuringiensis against housefly and chicks. The experiments and t he results can be summarised as follows: I. Susceptibility of different developmental stages of housefly, to -exotoxin of B. tlmriugieusis.

-1 -2 -3 -4 five concentrations (5 XlO , 5 X 10 , 5 X 10 ,5 X 10 and -5 5 X 10 ml/5g diet) of -exotoxin were tested against 2nd larval

instar of the housefly. The obtained results indicated that houseOy larvae were susceptible to all concentrations of the exotoxin. Toxicity was dose dependent as indicated by a positive rel ationship between the larval mortality and concentrations of exotoxin. Larval mortality of treated groups -3 ranged rrom25 to 100% and the LC 50 was 2 X 10 . Also obtained data show that P-exotoxin has a lowering effect on pupation rate, adult emergence rate, adult life span, female fecundity and egg hatchability. On the other hand, -exotoxin ;auses prolongation of larval and pupation periods: All the applied concentrations of -exotoxin caused a slight change in the sex ratio of newly emerged adults, in creasing male individuals than females when larvae were exposed to relatively high doses of the exotoxins. 2. Palhologicnl effect of JJ. tlwriugiensis on different tissue of A1. domestica larvae.

A- l\1orphological 'Lmormalities:

Some abnormalities were observed on pupae and adults after larval treatment with -exotoxin such as elongation and sclerotisation of pupae. Some adults which succeed to emerge, were incapable of expanding their wings and have smaller size than normal.

B- Histopathological abnormalities:

-exotoxin induced histopathological abnormalities in treated larval tissue as lysis of epidermal cells of body wall, hypertrophy and lysis of epithelial cells of alimentary canal nuclei sometimes appeared empty. The gastric caeca, Malpighian tubules, fat tissue, muscle tissue as well as tracheal system are also affected.

3. Histopathological effect of -exotoxin on Fayomi chicks.

Treatment of Fayomi chicks (28-30 days old) with the five -1 -2 -3 -4 concentrations of -exotoxin (5 XlO , 5 X 10 , 5 X 10 , 5 X 10 ml/5g diet) showed no histopathological effect on the tissue of the liver. While, the tissue of the kidney show a s li ght histopathological alterations represented by enlargement of few -1 -2 glomeruli, in case of' hi gher concentrations (5 XlO and 5 X 10 ) of -exotoxin.