Weight estimation and seasonal change of nutrients content in tree leaves fed in Japanese zoos
2017
Shiota, Y. (Kyoto City Zoo, Kyoto (Japan)) | Yayota, M. | Kawamura, A. | Tanaka, M.
Four genera of tree leaves (Robinia, Quercus, Ligustrum, and Morella) are popularly fed to giraffe and other herbivores in Japanese zoos. However, rational feeding of the tree leaves is not feasible because the amount of tree leaves offered is difficult to quantify and also little is known about the nutrient contents in the leaves. In this study, we estimated the weight of the leaves by using allometric relationship to the branch size and determined seasonal change of nutrient contents in the leaves. In all the species, the weight of leaves on the branch (Y) was well estimated from the area of cutting surface of the branch (X) (all species combined ; Y = 0.819Xsup(2.028), Rsup(2) = 0.784, P < 0.001). The nutrient contents every three months showed species-specific seasonal changes. This may be caused not only by maturity and regeneration of leaves but also by the changes of atmospheric condition before and after overwintering. However, binding protein content of the leaves was consistently high (23.5-79.8%CP) in all the species, suggesting that proteins in the tree leaves do not digested well in the reticulo-rumen of giraffes and other ruminants. The results of this study provide the fundamental information for rational feeding of tree leaves to zoo herbivores.
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