The oesophagus is a muscular tube comprised of cervical and thoracic regions. Several studies have clarified the histological structure of the oesophagus. However, its histoarchitecture in relation to variable dietary habits of each species is still unclear. In the current study, 21 pigeons, cattle egrets and ducks, n = 7, each was used. Macroscopically, the oesophagus of cattle egrets either the cervical or thoracic parts was the longest among the pigeons and ducks. Histologically, the oesophagus comprised of four distinct tunicae: mucosa, propria submucosa, musculosa and adventitia or serosa. A great structural variation in these layers among the three investigated species was recorded. In the cervical oesophagus of pigeons, the superficial squamous cells showed perinuclear halo zone, the propria submucosa was characteristically lacked any gland. Moreover, its musculosa was very thick. On the other hand, the intraepithelial glands were characteristically distributed along the whole length of the cattle egret’s oesophagus. Interestingly, the cervical esophagus of the ducks showed submucosal associated lymphatic tissue; diffuse and nodular Ultrastructurally, the oesophageal glands showed secretory granules of variable electron densities, electron‐lucent in the pigeons and ducks and electron‐dense in the cattle egrets.

The crop architecture varies among different avian species consistent with their feeding habits. Therefore, twenty-one of mature healthy male pigeons (granivorous), cattle egrets (carnivorous), and ducks (omnivorous), seven per species, were utilized for the histological, immunohistochemical, and ultrastructural analyses. Histologically, the mucosal folds were covered by non-keratinized stratified squamous epithelium in the three investigated species. The mucosal glands are only peculiar to the crops of the cattle egrets as well as the ducks, while the pigeons' crops were devoid of any secretory units. Morphometrically, the optical densities of the Alcian blue (AB) and periodic acid Schiff (PAS) reactions in the secretory glands, the area % of collagen fibers, the thickness of the tunica musculosa were measured and declared significant differences among the three studied avian species. Immunohistochemical reaction revealed ki-67 immuno-positive reactivity in the nuclei of basal cell layers of the crop epithelium in pigeons only. Regarding ultrastructure investigation, the covering epithelium of all studied species had been shown to be the basal layer of cuboidal to tall columnar cells with desmosomal junctions at the level of their cellular interdigitation, intermediate layers of large irregular polygonal cells with obviously increased cytokeratin filaments especially in the ducks and cellular interdigitation in between. The superficial layer of flat-shaped cells in the three investigated species manifested by desmosomal junctions in between but at the level of the surface squamous cells of the superficial layer, a fine lateral process is only inspected in the pigeons. In conclusion, the crop glands characterized by supranuclear electron dense secretory granules in the cattle egrets and electron-lucent in ducks.

Reprocessing food and agriculture waste (FAW) is of great interest, these residues can be converted into fruitful products, and lactic acid bacteria (LAB) are at the forefront of this approach. Therefore, the present study is aimed at exploring LAB bioconversion potential. Herein, Lactiplantibacillus plantarum MC39 (MZ769311) was used for the fermentation assay. The inhibitory effect against multi-drug resistant Klebsiella pneumoniae W8(MZ769363) and Enterobacter hormaechei U25 (MZ769310) was used as indicator for the productivity. Rice bran, wheat bran, alfalfa hay, reed straw, potato peels, banana peels, orange peels, and fava bean peels were used as fermentation substrates with different carbohydrate contents.The results showed that the maximum inhibitory effect was attained when orange peels were used after 96h of fermentation, followed by fava bean peels after 72h of fermentation. These findings suggest that the carbohydrate content of fermentation residues has a significant effect on organism's viability, and orange peels could be a suitable feedstock substrate in solid state fermentation, producing an antimicrobial agent that can inhibit MDR Gram-negative pathogens.