The Effects of Deoxynivalenol on the Ultrastructure of the Sacculus Rotundus and Vermiform Appendix, as Well as the Intestinal Microbiota of Weaned Rabbits

Deoxynivalenol (DON) is a mycotoxin found in grains that poses a potential threat to human and animal health, and the gastrointestinal tract is the primary target organ. There are few studies focused on the toxicology of DON to rabbits, especially on the relation among DON, microbiota, and the gut-associated lymphoid tissue. A total of 30 weaned rabbits (35 d) were evenly divided into the control group and DON group (1.5 mg/kg bodyweight (BW)) based on their body weight. After a 24-day trial, the ultrastructures of the sacculus rotundus and vermiform appendix were observed using a scanning electron microscope and transmission electron microscopy. The morphology and microflora in the ileum, caecum, and colon were also examined. The results proved that the ultrastructure of the sacculus rotundus and vermiform appendix, as well as the integrity of the intestinal barrier (especially for the ileum), were impaired after DON was administrated to the rabbits. Compared to the control group, the relative abundance and diversity of the microflora decreased in all three intestinal segments in the DON group, particularly in the ileum and caecum. In conclusion, the toxic effect of DON on weaned rabbits may be performed by destroying the structure of the sacculus rotundus and vermiform appendix, as well as affecting the structure and diversity of the intestinal flora.

Investigation of significant microRNA-mRNA pairs associated with nonspecific digestive disorder in rabbits

Nonspecific digestive disorders (NSDD) are one of the major intestinal problems in rabbit, with considerable economic losses in industrial rabbit farms. MicroRNAs (miRNAs), as small non-coding RNAs, have significant biological involvement in intestinal disorders. In this study, we investigated the expression levels of 25 genes and 25 miRNAs in ileum, rabbit sacculus rotundus (RSR) and colon tissues from 9 rabbits with different severity of NSDD. These molecules have been found to be related to NSDD or inflammatory bowel disease, which will help recognise the miRNA-mRNA pairs. Finally, 108 possible pairs of miRNA-mRNA pairs with an anti-correlation were identified by Pearson’s correlation analysis between differentially expressed 25 miRNAs and 23 mRNAs. Ninety-five of these miRNA-mRNA pairs were hitherto unexplored, and their roles in NSDD biology require further elucidation. Our results give a clue to the potential miRNA-mRNA pairs for the NSDD that can further improve the understanding of the pathogenesis of NSDD in rabbit.

Morphological and histomorphometrical study of the Sacculus rotundus at different postnatal ages in indigenous rabbit

Current investigation was carried out to explore structural developmental changes of the acculus rotundus in indigenous rabbits at different postnatal ages. To conduct that, morphological, histological and morphometrical approaches were employed on 24 rabbits at ages one, ten, fifteen and forty days. The findings indicated that in one day kits, the Sacculus rotundus cannot recognized with the naked eye but in the next advanced ages it appeared as expanded pear-like structure situated at the end of ileum. It opened into the 2nd gyrus at the base of cecum by saccorotundocecal orifice. Because it extends for 1-2 millimeters inside the lumen of the cecum, an annular ridge formed encircles the site of this opening. Length and width of SR was increased significantly by age progression. The main four layers of the alimentary canal were presented in the wall structure of Sacculus rotundus but with apparent variations in its structural constituents and dimensions. Two types of epithelia were recognized in its mucosa, villus epithelium and follicular associated epithelium. The lamina propria was very thick and full of well-developed nodular and diffuse lymphoid tissue alongside the whole circumference of its wall even in the newly born kits. In conclusion, the SR might be considered as primary lymphoid organ in rabbit.

A morphological and morphometrical study on the sacculus rotundus and ileum of the Angora rabbit

The aim of this study was to reveal morphological and morphometrical properties of the sacculus rotundus (SR) and ileum in the Angora rabbit. For this purpose, a total of thirteen adult healthy Angorarabbits of both sexes were used. At the level of the junction of the ileum and SR, the ileum invaginated into the SR by protruding in 9 Angorarabbits, but joined directly the SR in 21. Numerous aggregate lymph follicles located just under the tunica serosa formed outstanding macroscopic polygonal areas on the external surface of the SR. In the inner wall of the SR, irregular projections were seen grossly. The saccorotundocecal orifice was found to be bordered laterally by two folds facing the cecum. These folds enclosed small polygonal spaces with mushroom shaped protrusions. The mean lengths and weights of SR and ileum in male were larger than those in female, and the related values also had statistical significance (P < 0.05). Compared with the ileum, the SR had short and thick villi, had a large amount of crypts and aggregated lymphoid follicles, and had a much thicker wall and much wider lumen. The crescent-like-hollows were detected between the lamina propria and the apical portions of the lymph follicles. The results from this study are thought to shed light on future studies on the digestive system and proper diagnosis of pathological disorders related to it in the Angora rabbit, and to contribute to the present morphological knowledge on the SR and ileum in this species.

Effects of Glucomannan on the Sacculus Rotundus and Peripheral Blood Lymphocytes in New Zealand Rabbits during Aflatoxicosis

This study was aimed to determine the effects of the glucomannan added to aflatoxin- (AF-) contaminated diet on the sacculus rotundus and peripheral blood lymphocytes of New Zealand rabbits by histological and enzyme histochemical methods. Twenty-four adult rabbits of both sexes were divided into four equal groups, namely, as control, glucomannan 0.2 g/day, AF 125 μg/kg/day, and glucomannan combined with AF. The animals in all groups were treated for 12 weeks by the above-mentioned diet. When compared to control, AF-treatment caused significant decrease in alpha-naphthyl acetate esterase- (ANAE-) positive peripheral blood lymphocyte (PBL) percentages. The addition of the glucomannan to AFcontaining diet recovered the adverse effects of AF on sacculus rotundus and increased the ANAE-positive PBL counts. These results suggested that glucomannan was effective against the negative effects of AF in rabbits.