BHC Not Found to Reduce the Shell Quality of Hens' Eggs

Abstract

SEVERAL organochloride pesticides are said to have detrimental effects on the eggshell quality of a variety of avian species. The eggshell thickness of ducks is reduced by feeding dieldrin and DDE^1,2; that of American kestrels by DDE³; of Japanese quail by DDT⁴ and of American sparrow hawks by a mixture of DDT and dieldrin⁵. Indeed, a mathematical relationship seems to exist between DDE residues and shell thinning⁶. Major structural defects, apart from shell thinning, have also been found to occur in the eggshells of quail fed DDT or chlordecone⁷. Now that the use of DDT has been, or is about to be, banned in many parts of the world, γ-BHC (lindane) is becoming the most widely used pesticide in this class. However, little is known about its effects on birds. Whitehead et al.⁸ found that feeding γ-BHC at moderate levels (about 100 mg/kg diet) to hens permanently reduced their egg production by 25%, although no detrimental effect was observed on shell thickness. In contrast, Sauter and Steele⁹ have claimed that feeding it to hens at a lower level, 10 mg/kg diet, slightly reduced shell thickness.