The purpose of the present study was to investigate the effects of dietary zinc (Zn) supplementation on antler growth, haematological biochemical parameters and nutrient digestibility in farmed male sika deer. Twenty-five 2-year-old growing male sika deer were randomly divided into five Groups (A, B, C, D and E; 5/group). Animals in Groups A, B, C, Dand E received 0, 5, 15, 40, 100 mg Zn/kg, respectively. Group A, without supplementation acted as a control. The treatment diets were the same basal diet supplemented with 5, 15, 40 and 100 mg Zn/kg (provided as Zn methionine), respectively. The results showed that the digestibility of dry matter (DM) and crude protein in Groups D and E were greater than that in Groups A, B and C (P < 0.05). Digestibility of neutral detergent fibre in Group E was higher than in the control group (P < 0.05). Plasma Zn concentrations were increased by Zn supplementation and were higher (P < 0.01) for the treatment groups supplemented with 15, 40 and 100 mg Zn/kg DM than for the control and 5 mg/kg Zn groups (P < 0.01). Faecal Zn content in Groups D and E was higher than that in Group A (P < 0.01). The content of albumin in plasma from Group E was greater than in the control and Groups B, C and D (P < 0.05). The concentrations of testosterone in plasma from Groups C, D and E were decreased (P < 0.05) compared with the control. The days between antler initiation and harvesting of deer in Groups D and E were decreased (P < 0.05). Average daily gain of fresh antler and dry antler of deer in Groups D and E was significantly higher than that in the control group (P < 0.05). In conclusion, a control diet containing 58.6 mg Zn/kg was inadequate for achieving optimal productivity for sika deer. The recommended Zn supplementation is from 76.7 to 99.0 mg/kg for 2-year-old male sika deer.
Dietary calcium supplementation affects nutrient digestibility and antler-production performance during the antler-velvet growth period of male sika deer
