A total of 32 wild Hokkaido sika deer ( Cervus nippon yesoensis ) were shot (13 in summer, nine in autumn and 10 in winter) in the Syari district, Shiretoko Peninsula of Hokkaido Island, Japan. The ingested foods, rumen fermentation parameters and microbes were determined to evaluate digestive strategy and food availability in each season. Ingested foods and ruminal characteristics greatly varied by season. Rumen digesta mainly comprised of graminoids in summer, graminoids and agricultural products in autumn, and bark and twigs in winter. Rumen pH showed seasonal differences ( P < 0.05) and was lowest in summer, highest in winter, and intermediate in autumn, reflecting the seasonal differences in ruminal concentration of total volatile fatty acids which were significantly lower ( P < 0.05) in winter than in summer and autumn. Acetate proportions were significantly higher in winter than in other seasons ( P < 0.05), while the opposite trend was seen in proportions of propionate and butyrate. Rumen ammonia levels showed significant seasonal differences ( P < 0.05), decreasing from summer to autumn to winter. Rumen protozoa levels in autumn and winter decreased to 28 and 10% of the levels observed in summer, respectively ( P < 0.05 for both). The rumen bacteria level in winter was lower ( P < 0.05) than that in autumn, but no difference was seen for the other seasonal comparisons. Gram negative cocci were present in significantly higher proportions in winter than in other seasons ( P < 0.05), while Gram negative curved rods were less frequently observed in winter ( P < 0.05). Based on these results, wild sika deer in this area are shown to survive with rumen microbial populations altered with the dietary conditions that vary greatly by season.

| INTRODUC TI ONWild ruminant animals are excellent models for the functional surveillance of rumen microbes (Kobayashi, 2006), since these animals are expected to harbor specific rumen microbes in response to the dietary conditions to which they are exposed. Changes of rumen microbiota likely depend on the area in which the wild animals inhabit. In particular, harsh dietary conditions might select for rumen microbiota to digest and ferment fibrous materials as a main dietary ingredient in order to maximize nutrient extraction. This is because the rumen is the main digestive organ for degrading fibrous foods by microbes and also acts as a reservoir of ingested foods (Itabashi, 1998).Hokkaido, the northernmost island of Japan, is home to more than a million head of wild sika deer (Hokkaido sika deer, Cervus nippon yesoensis), many of which live in snowy areas with limited access to food. We have elucidated seasonal changes of body size, ingesta, body fat reserve, and rumen fermentation products of sika deer in the Shiretoko Peninsula of Hokkaido, characterized by severe winter conditions (long duration of low temperatures AbstractRumen digesta was obtained from wild Hokkaido sika deer to compare bacterial flora between summer and winter. Bacterial flora was characterized with molecular-based approaches and enrichment cultivation. Bacteroidetes was shown as a major phylum followed by Firmicutes, with similar proportions in both seasons. However, two phylogenetically unique groups in Bacteroidetes were found in each season: unknown group A in winter and unknown group B in summer. The ruminal abundance of unknown group A was the highest followed by Ruminococcus flavefaciens in winter.Moreover, the abundance of these two was higher in winter than in summer. In contrast, the abundance of unknown group B was higher in summer than in winter. In addition, this group showed the highest abundance in summer among the bacteria quantified. Unknown group A was successfully enriched by cultivating with oak bark and sterilized rumen fluid, particularly that from deer. Bacteria of this group were distributed in association with the solid rather than the liquid rumen fraction, and were detected as small cocci. Accordingly, unknown group A is assumed to be involved in degradation of fibrous materials. These results suggest that wild Hokkaido sika deer develop a rumen bacterial flora in response to changes in dietary conditions. K E Y W O R D Secology, fiber digestion, quantitation, rumen bacteria, sika deer

We assayed the serum leptin concentration and determined its correlation with the kidney fat mass (KFM), kidney fat index (KFI), and femur marrow fat (FMF) indices in 12 Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) collected in April, June, and October 2000. The KFM and KFI in April and June were both significantly lower than those in October. The leptin concentrations in April and June and in October were 1.222-1.521 ng mL -1 HE (Human Equivalent) units and 1.676-2.63 ng mL -1 HE, respectively, without overlapping. The relationships between the leptin concentration and the KFM, KFI, and FMF were all significant. Therefore, we conclude that the serum leptin concentration can be used as a new index for fat reserves in Hokkaido sika deer. However, reliable results could not be obtained from four samples collected in April and June when the deer were in a lower nutritional status. This may be due to the limited sensitivity of the antisera in the commercial multi-species leptin RIA kit used. For practical use in wildlife biology, species-specific leptin assays should be developed to eliminate this problem. W R 0 2 0 1 6 L e p t i n c o n c e n t r a t i o n a s a n i n d e x f o r f a t r e s e r v e s M . S u z u k i e t a l .

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