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Gewählte Publikation:

Publikationstyp: Dissertation

Jahr: 2006

AutorInnen: Popescu, F

Titel: The effect of season, sex and age on gut length, digestion and caecotrophy in European hares.

Quelle: Dissertation, Vet. Med. Univ. Wien, pp. 68.

Betreut von:

Arnold Walter

The European hare, a small herbivore with hindgut fermentation, occupies habitats in which food quality changes across seasons. In the reproductive season females must cope with high energetic stress, such as lactation and pregnancy, while males pay the energetic costs for competing for mates. Previous research data has suggested that the gastrointestinal tract has evolved a flexible design in response to food quality and energetic demands. In this study, changes in the nutrient content and breeding requirements over the year affected the size and weight of most intestinal segments of both sexes. In May and August it was determined that a higher quantity of fiber versus a lower protein proportion and the length and content of the intestinal parts were generally higher than in November and February. In the reproductive season, when the demands of pregnancy and lactation were highest adult females enlarged the small intestine and caecum. Higher amounts of protein and ash and lower proportions of fiber were found in the caecum than in the stomach (food part) and colon (hard faeces) content. This supports the hypothesis that the fiber is poorly digested and the caecotrophy is of great nutritional significance for the hares. Between the two age classes (adults and subadults) there was not significant difference concerning the amount of nutrients and the dimensions of the digestive tract. The fatty acids content of the GI tract showed a pronounced winter-summer difference, with a higher proportion of polyunsaturated fatty acids and lower monounsaturated fatty acids and saturated fatty acids in August than in November. Females had higher amounts of polyunsaturated fatty acids in their stomachs and small intestines during the reproductive season (lactation and pregnancy). The concentrations of odd-chain fatty acids C15:0 and C17:0 were significantly higher in the caecal content than in the stomach or small intestine, suggesting they are produced by the microorganisms. Higher quantities of saturated fatty acids attributable to microbial fermentation were determined in the caecum and colon than in the small intestine, in contrast also with the PUFA content which was decreasing to the end of the intestinal tract. The presented data suggest that higher energy demands and seasonal nutrient variation have selected for changes in gut size and capacity in the European hare and these digestive strategical mechanisms, together with the caecotrophy behavior, are adaptations for survival in their changeable habitat.

Gastrointestinaltrakt / Feldhasen / Verdauung / Fettsaeuren / Caecotrophie

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