Analysis Of The Utilization Of Food Resources By The African Wood Mouse Hylomyscus Denniae Endorobae (Rodentia: Muridae) From Ihururu Forest, Kenya

ABSTRACT

Hylomyscus denniae endorobae is a rodent important in ecosystems as predator, prey, seed disperser, determinant of forest tree growth and structure as well as a contributor to biodiversity which subsequently plays a role in natural livelihood and national development. Fragmentation of tropical rain forest continues to pose a serious threat to species diversity, which leads to decreased natural income, primary production and general breakdown of an ecosystem. This in turn influences food resources and energy available to animals such as H. d. endorobae. With habitat destruction, H. d. endorobae will get to human habitat, destroy stored seed crops and transmit diseases. Evaluating gut morphology changes in response to different diets gives an insight into how animals can survive with changes in the natural habitat. The study was done to evaluate how H. d. endorobae adapts to different diets in the face of food scarcity in order to make informed decisions on conservation of the species. The purpose of this study was to analyze utilization of food resources by H. d. endorobae. Thirty male rodents (H. d. endorobae) weighing between 35-50g were trapped from Ihururu forest in Nyeri, Kenya, one of the natural habitats of the rodent species experiencing a lot of anthropogenic activities. Microscopic examinations of faeces collected from the trapped animals were done to establish the diet of the animal species in its natural habitat. The individuals were dissected and morphological measurements taken to establish gut size. Slides of different gut sections were microscopically examined to establish the number and length of villi. Nine other adult male rodents were randomly grouped into threes, caged individually and fed on 80g of different diets for six months to determine the influence of diet on gut morphology, digestibility and absorption efficiency. Results showed that H. d. endorobae consumes 70.7% seed, 22.6% plant leaf and 6.8% animal matter. There was no correlation between the mean body weight (40.1 ± 3.9g) and the mean total gut length (62.6 ±1.3cm) of field collected animals. The mean gut lengths were 62.6 ± 1.3cm, 58.5 ± 4.5cm, 55.7 ± 1cm, and 57.1 ± 2.3cm for field collected animals, wheat, kale and omnivore diets, respectively. Also, gut length did not show any significant differences (p = 0.889) between H. d. endorobae fed on different diets. Regression analysis showed no significant difference between diet and stomach volume (P = 0.205). There was significant correlation (p < 0.05) between diet and number of villi in the duodenum and caecum of field collected animals and those fed on wheat and large intestine and caecum of those fed on kale. Also, there was significant correlation (p < 0.05) between diet and length of villi in all regions of the gut except in the caecum (P = 0.232) of animals fed on omnivore diet. Diet influenced digestive efficiency (p = 0.007) with kale diet having the lowest efficiency (77.69%) compared to wheat diet (95.12%) or omnivore (94.29%). These results suggest that H. d. endorobae meets its energy demands with minimal gastrointestinal changes and probably increased food intake. It is recommended that the natural habitats of H. d. endorobae should be maintained and conserved to prevent its migration to human habitats and probable species erosion.