Abstract

Diflubenzuron (Dimilin), an inhibitor of insect chitin synthesis, was fed to neo-hatched chicks in concentrations of 50 to 2000 ppm in the diet. The activity of the vertebrate hexosamine transferases responsible for glycosa-minoglycan (mucopolysaccharide) formation was monitored by measuring the in vivo rate of incorporation of a labeled precursor into hyaluronic acid and chondroitin sulfate of skin. No inhibition of biosynthesis was noted at any concentration; indeed the insecticide appeared to stimulate the synthesis of these compounds. After 3 weeks on the diet, chicks eating 1000 and 2000 ppm diflubenzuron showed obvious signs of cyanosis, and sulfhemoglobin was demonstrated in the blood of chicks eating more than 200 ppm. The amount of sulfhemoglobin appeared to be related to the dietary insecticide content and the highest level seen was 13% of total hemoglobin in the 2000 ppm group after 31 days. These values returned to normal within 3 weeks when diflubenzuron was removed from the diet.

Key words: Pesticides, insect growth regulators, diflubenzuron, chicks, glycosaminoglycan, sulfhemoglobin, Gallus domesticus.