Reported literature provides limited information on histology and histomorphometry of its GIT organs and gut associated lymphoid tissues (GALT) of wild duck (Gadwall; Anas strepera). This study seeks to document histology and histomorphometric features of above-mentioned organs of Gadwall and compare them to those of the domestic duck.
Seven adult domestic and wild ducks were collected from local market and Chashma Barrage, Mianwali, respectively. After slaughtering, samples from esophagus, proventriculus, gizzard, pyloric tonsils, small intestine and cecal segments were collected. GIT and visceral organs length and weight were recorded respectively. All the samples were processed by paraffin embedding technique followed by H&E and Alcian blue-PAS staining techniques. The slides were observed under bright field microscope for measurements (LABOMED® USA). For esophagus, thicknesses of layers of its wall were recorded. For proventriculus and gizzard, histological description was considered. For small intestines, villus height, width and surface area, crypt depth, thickness of lamina propria, muscularis mucosae and tunica muscularis were recorded, and IELs and goblet cells were counted. For pyloric and cecal tonsils, height, width, number and distribution area of lymphatic nodules were recorded. Independent sample t-test was used to analyze the data (mean ± SEM). Differences was considered significant at p<0.05.
The results showed that in wild ducks live body weight was lower as compared to the domestic ducks. In wild ducks esophagus length was lower as compared to the domestic ducks. The relative weight of the esophagus was higher in the wild ducks as compared to the domestic ducks. The relative weights (filled and empty) of proventriculus, gizzard and small intestine were higher in the wild ducks as compared to the domestic ducks.
Summary
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In wild ducks large intestine length was higher as compared to the domestic ducks. In the wild ducks relative weights of spleen, pyloric tonsils and Bursa of Fabricius were higher as compared to the domestic ducks.
The results of histomorphometry of the different layers of esophagus showed that epithelium thickness was lower in the wild ducks as compared to the domestic ducks. While thickness of the lamina propria and muscularis mucosa were higher in the wild duck as compared to the domestic ducks. In the duodenum villus width, villus surface area and muscularis mucosa thickness were found lower in the wild ducks, as compared to the domestic ducks. In the jejunum thickness of lamina propria and tunica muscularis were higher in the wild ducks as compared to the domestic ducks. In wild ducks villus height, villus surface area, crypt depth and tunica muscularis thickness of ileum were higher as compared to the domestic ducks. In cecal and pyloric tonsils, length width and number of the lymphatic nodules were lower and higher respectively in the wild ducks as compared to the domestic ducks. In the wild ducks, intraepithelial lymphocytes count in duodenum was lower as compared to the domestic ducks. While the intraepithelial lymphocytes count in ileum was higher in the wild ducks as compared to the domestic ducks. In duodenum of wild ducks acidic, mixed goblet cell count and their total count was lower (p<0.05) as compared to the duodenum of domestic ducks.
In conclusion wild duck has slightly better developed immune and GIT organs than those of the domestic duck.