Induction of vitamin A deficiency in turkeys

The objective of this study was to determine the relationship between the h epatic vitamin A (VitA) level and the pathologic changes in the oropharynx and esophagus of VitA-deficient turkeys. Study turkeys were provided with a diet sufficient (11,000 IU/ kg) or deficient (2750 IU/kg) in VitA from 4 t o 17 wk of age. Body weight, bacterial culture, and tissues from internal o rgans were collected at weekly intervals. VitA deficiency causes epithelial tissue damage in poultry. This epithelial damage was seen grossly as white plaques in the oropharynx and esophagus and histologically as squamous met aplasia of mucosal glands and keratinization of epithelium. No significant difference in body weights was seen among the groups. Moreover, no pathogen ic bacteria was isolated during sampling periods. Liver VitA levels decline d significantly after consumption of Low VitA diet four 3 wk and were deple ted after 5 wk. Squamous metaplasia due to VitA deficiency developed in the esophagus after 3 wk and in the oropharynx after 4 wk of consuming a VitA- deficient diet.