Pathogenicity of ascaridia galli infection in broiler chicken with special reference to weight gain

Abstract

A study carried out to assess the pathogenic effect of the developmewntal stages of Ascaridia galli in broiler chicks for a period of eight weeks, revealed clinical signs like general weakness, unthriftiness, ruffled feathers and loss of appetite, besides the delayed development of comb, wattles and feathers. On post – mortem examination of the experimentally infected chicks, large numbers of larvae were recovered from 2nd day PI onwards and the lumen larvae were detected from 14th day PI. The intestinal contents were frothy, mucus mixed and had many immature worms. In the small intestine the worms embedded in the mucosa with their anterior extremities. Histopathological studies revealed disruption of villi, desquamation of epithelium, infiltration with monocular cells, focal necrosis, congestion and haemorrhage in the mucosa and cystic changes of mucosal glands. Sections of larvae in the mucosa at different histological locations were detected on 4th, 10th, 14th and 17th days PI. In addition, cut sections of degenerated larvae were also observed. Haematological studies indicated a statistically significant increase in erythrocyte sedimentation rate, total leucocyte count, total heterophil and eosinophil counts. Packed cell volume, haemoglobin content and total erythrocyte count were significantly decreased. Lymphocyte count was significantly decreased (P < 0.01) in all the infected groups upto 37th day PI; later the count was gradually increased in all the infected groups. The mean body weight and mean body weight gain in the infected groups of chicks were significantly lesser than the control group chicks (P <0.01). The mean weekly feed intake and mean weekly feed conversion ratio were lesser in the infected groups of chicks than control ones, although the difference was not statistically significant. The morbidity rate was high in all the infected chicks, but mortality was not recorded during the experimental period. Coprological study confirmed the maturation period for A. galli in groups A, B, C and D as 59, 59,50 and 44 days respectively.