Pathology of infectious diarrhea of infant rats (IDIR) induced by an antigenically distinct rotavirus

Suckling rats were inoculated with a group B rotavirus to determine the progression of the morphologic changes induced in the intestine by this virus. Several changes were observed by light microscopy 1 day after viral inoculation: shortening of small intestinal villi, villous epithelial necrosis, and villous epithelial syncytia. The lesions were most often present in the distal small intestine, although other small intestinal segments were affected to a lesser degree. By day 3 post-inoculation, epithelial necrosis, and syncytia were no longer present; however, the villous epithelium was disorganized and irregularly vacuolated, and intestinal crypt epithelium was hyperplastic. Alterations in villous height to crypt depth ratios were present in portions of the small intestine for the remainder of the 12-day study period. Epithelial syncytia appeared to form by the breakdown of the lateral interdigitating membranes of the absorptive villous epithelium. Viral particles, abundant in the syncytia, appeared to form from amorphous or reticular arrays of viral precursor material. Group B rotaviral antigens, as detected by indirect immunofluorescence, were present in large amounts in the small intestinal villous epithelium only on the first day after viral inoculation. These studies show that two important diagnostic features of group B rotaviral infections of rats, epithelial syncytia and viral antigen as determined by immunofluorescence, are present only on the first day of disease. These findings should be taken into consideration when attempting to diagnose disease induced by this agent.     

The effects of creep feed composition and form and nursery diet complexity on small intestinal morphology and jejunal mucosa-specific enzyme activities after weaning in pigs

Fifty-six litters from first-parity sows standardized to 12 piglets were used to determine the effects of creep feed composition and form and the provision of low- or high-complexity nursery diets on the evolution of small intestinal histomorphology and jejunal mucosa-specific enzyme activities postweaning. At 5 d of age, litters (initial bodyweight [BW] 2.31 ± 0.61 kg) were assigned to one of four creep feeding regimens (n = 14): 1) commercial creep feed (COM), 2) liquid milk replacer (LMR), 3) pelleted milk replacer (PMR), or 4) no creep feed (NO). At weaning (21 d of age), six pigs per litter were provided a HIGH- (contained highly digestible animal proteins) or LOW- (contained corn and soybean meal as main protein sources) complexity nursery diet (n = 7). At 21, 28, and 59 d of age, two pigs per pen (one castrated male and one female) were euthanized, and ileal and jejunal segments for histomorphological measurements and jejunal mucosal scrapings were collected to determine specific mucosa enzyme activities. At weaning, pigs provided COM had a greater ileal absorptive capacity (M) than LMR or NO, which were not different (14.1 vs. 10.4 and 10.5 ± 0.9 μm²; P < 0.05); PMR was intermediate. On days 28 and 59, M was not different among pigs regardless of creep feed treatments. Pigs fed LOW had reduced jejunal villus height (VH; P < 0.001) and M (P < 0.001) on day 28 vs. day 21. The VH and M were not different for pigs fed HIGH or LOW by the end of the nursery period. For all dietary treatments except COM-HIGH and COM-LOW, jejunal mucosal maltase-specific activity was not different between days 21 and 28 of age but greater on day 59 (P < 0.05). For pigs that received COM-HIGH, maltase-specific activity was not different between days 21 and 28 but greater on day 59 than day 28 (P < 0.05). For pigs that received COM-LOW, maltase-specific activity was not different between days 21, 28, and 59. Regardless of creep or nursery treatment, sucrase-specific activity was the greatest on day 59, followed by days 21 and 28 (P < 0.001), and lactase-specific activity was greater on day 21 than on days 28 and 59 (P < 0.001), which were not different. Therefore, pigs that provided LOW diet had greater villus atrophy and reduced M during the first week after weaning vs. pigs that provided HIGH, regardless of creep feeding regimen, but were able to recover by the end of the nursery period.     

III. Buchbesprechungen

Ohne Zusammenfassung     

III. Buchbesprechungen

Ohne Zusammenfassung     

III. Buchbesprechungen

Ohne Zusammenfassung     

III. Buchbesprechungen

Ohne Zusammenfassung     

Zur Frage der anatomischen Unterscheidbarkeit des Holzes vonPinus silvestris L. undPinus nigricans Host

Ohne ZusammenfassungMit 7 Abbildungen     

III. Buchbesprechungen

Ohne Zusammenfassung     

III. Buchbesprechungen

Ohne Zusammenfassung