Morphometrical and histological effect of the crop in producing crop milk: a Comparative study with blood supply between brooding and non-brooding diamond dove and indonesian chicken

The current study was focused on the crop of diamond dove and Indonesian chicken to determine the location, shape, dimensions, blood supply and histological changes occurred during brooding and chick feeding and non-brooding periods to know differences led to the formation of crop milk. Twenty-four sexually mature healthy birds of the two types collected and rose until reach the brooding and feeding period divided into brooding and non-brooding groups, from August 2024 to March 2025. The crop in brooding diamond dove contained two lateral lobes with smooth central lobe, mucosal surface of the lateral lobes displayed irregular folds in female and hexagon-shaped folds in male and was packed with crop milk, while in non-brooding it was membrane-like crop of asymmetrical lobes with smooth inner surface free of folds in both sexes. Whereas Indonesian chicken crop appeared as a semicircular ring, its inner surface had irregularly shaped mucosal folds of club-like shape in brooding and non-brooding birds. Histological results in both diamond dove and Indonesian chicken revealed that crop's wall comprised four tunicae; mucosa, submucosa, muscularis and adventitia. Tunica mucosa contained well-developed mucosal folds covered with stratified squamous keratinized epithelium, that characterized in brooding diamond dove by the increase in: number of cells with peri-nuclear hallow zone that being desquamated and sloughed and undergo fatty changes forming crop milk, and the depth of rete pegs which extending from germinal layer down into lamina propria which was free of glands.