Zbl. Vet. Med. A, zyxwvutsr 22, 557 zyxwvuts - 563 (1975) @ 1975 Verlag Paul Parey, Berlin und Hamburg ISSN 0044-4294/ASTM-Coden: ZVRAAX zyxwvu From the Departments zyxwv of Pathology, Veterinary Medicine and Animal Physiology, Faculty zyxwvu of Veterinary Medicine, Cairo University Toxic Effects of Diazinon on the Gonads of Fowls BY S. M. SOKKAR, MEDHAT A. MOHAMMED and F. A. SOLIMAN With 5 figures and one table (Received for publication February 19, 1974) The use of insecticides in the poultry industry is an essential means of control and eradication of ectoparasites. This involves the hazards resulting from their misuse, leading to their introduction into the body either orally or through the skin (GLEES and WHITE, 1960). There are several reports in the literature on the adverse side-effects of organophosphorus compounds on different breeds of birds at different ages and stages of production. The signs of poisoning include mainly dyspnoea, inappetence, diarrhoea, convulsions, paralysis and death (CHRISTIANSEN and DALGAARD-MIKKELSEN, 1961; SHAW et al., 1964; SAUTER and STEELE, 1972). Egg production was considerably reduced when laying hens were fed Lindane (NIKOLIC, 1963), Coumaphos (SHAW et al., 1964) and D.D.T., Diazinon, Lindane or Malathion (SAUTER and STEELE, 1972). We came across retarded e g production in a flock of crossbred laying hens of the variety ed our interest in the effects of this insecticide on the gonads, with reference to hormonal control and the pathological changes. Material and Methods Forty Dokki-4 chickens, four months old, were used. Twenty-six hens and 5 cocks were dipped in Diazinon at a concentration of 1/1OOO, which was the level used by mistake in the original flock. Seven hens and two cocks were kept as control. From the Diazinon treated birds, 16 hens and three cocks died within 3 days after dipping. The survivors and the untreated controls were maintained on a commercial balanced laying hen ration until the age of 8 months. All the birds were then slaughtered and their blood was collected separately. The carcases were examined for gross lesions, with particular attention to the gonads. The latter were fixed in 1OO/o neutral formalin, embedded in paraffin and 6 ,u sections were stained with H & E. Dokki-4 a zyxwvu B ter exposure to Diazinon dips at the age of zyx 4 months. This stimulat-