Effects Of Tannic Acid On Ingestion,Digestion,Testosterone And Thyroid Hormoneof Forest Musk Deer

Forest musk deer (Moschus berezovskii) mainly ingest fresh leaves of high protein and low cellulose in the wild, and the fresh leaves are usually rich in tannic acid. Because the captive forest musk deer ingest only few plant species that are bound to resulting in nutrient deficiency, so are the problems of reduction of reproduction and musk secretion, and infection of disease becoming increasingly severe. In the current study, different concentrations of tannic acid were added to food of male forest musk deer. The effects of different concentrations of tannic acid (0%,1%,2%,3%,4%) on food selection of the male forest deer were firstly explored using a method of cafeteria measurement. Secondly, fresh feces of the male forest musk deer were collected, and the effects of tannic acid (1%,2%,3%.4%) on nutrient digestibility were investigated by an acid-insoluble ash analysis (AIA). Finally, the effects of different levels of tannic acid on testosterone and thyroxine T3 in feces of the male forest musk deer were studied using the enzyme-linked immunosorbent assay (ELISA) and the radioimmunoassay (RIA) respectively. The aims of these approaches were to explore the effects of tannic acid on food seclection, nutrient digestion, and metabolic and reproductive physiology of the captive forest musk deer. The results might be useful for scientific management of forest musk deer health, and could provide theoretic supports for formulating its full-nutrient diets and establishing its artificial fodder forests. The main conclusions are as follows:Effects of different concentrations of tannic acid on food selection of the forest musk deer:Feed intake of forest musk deer decreased with increasing concentrations of tannic acid. The average feed intake was 7.64+0.60g in control group (0%) and 3.70±0.62g,3.44±0.55g,2.86±0.39g,1.54±0.47g in the experimental groups (1%.2%.3% and 4%) respectively. The feed intake in the group witihout addition of tannic acid was extremely significantly higher than those in groups adding different concentrations of tannic acid (P<0.01). The feed intake in the group adding 1% tannic acid was higher than those in groups adding 2% and 3% tannic acid, but the differences were not significant (P>0.05). The feed intake in the group adding 1% tannic acid was extremely significantly higher than that in the group adding 4% tannic acid (P<0.01). The feed intake in the group adding 2% tannic acid was higher than that in the group adding 3% tannic acid, but the difference was not significant (P>0.05). The feed intake in the group adding 2% tannic acid was significantly higher than that in the group adding 4% tannic acid (P<0.05). The feed intake in the group adding 3% tannic acid was higher than that in the group adding 4% tannic acid, but the difference was not significant (,P>0.05).Effects of different concentrations of tannic acid on nutrient digestibility of the forest musk deer: After the male forest musk deer ingested diets containing 1%,30% or 4% tannic acid, crude protein digestibility was higher than that of the control value (I0), but the difference was not significant (P>0.05). However,2% tannic acid addition to the diets significantly increased the crude protein digestibility (P<0.05). Futhermore, the dry matter and neutral detergent fiber digestibility of the forest musk deer after ingesting different levels of tannic acid were higher than I0, but the difference was not significant (P>0.05).Effects of different concentrations of tannic acid on fecal testosterone and thyroxine T3 of the forest musk deer:After adding different concentrations of tannic acid, the fecal testosterone level was increased with decrement of the tannic acid concentrations, and the increasing rate was 162.87%,99.22%,61.02% and 15.15% with the decreasing of the tannic acid concentrations from 1% to 2%,2 to 3%, and 3% to 4%, respectively. In the group adding 1% tannic acid, fecal testosterone level was extremely significantly higher than I0 (P<0.01). In the groups adding 2% and 3% tannic acid, fecal testosterone levels were significantly higher than I0 (P<0.05), and in the group adding 4% tannic acid, fecal testosterone level showed not significant difference to I0 (P>0.05). The different concentrations of tannic acid had no effect on fecal thyroxine T3 of the male forest musk deer (P>0.05).