Dietary calcium supplementation affects nutrient digestibility and antler-production performance during the antler-velvet growth period of male sika deer

Abstract

Effects of calcium (Ca) supplementation on nutrient digestibility, physiochemical characteristics and antler growth in farmed male sika deer were investigated. Eighteen sika deer (6 years old, 105.50 ± 5.05 kg) were assigned into the following three treatments where they had ad libitum access to water for 90 days: (1) control (C), basal diet containing 0.5% Ca; (2) Ca1.10, basal diet supplemented with 0.6% Ca; and (3) Ca1.70, basal diet supplemented with 1.2% Ca. The basal diet contained 0.50% Ca and 0.34% phosphorus (P). Each group consisted of the same ratio of Ca to P (provided as CaCO3 and CaHPO4). The results showed that the digestibility of dry matter (DM) and crude protein in the Ca1.70 group was lower than in the other two groups. The digestibilities of Ca, P and neutral detergent fibre in the Ca1.10 group were higher than those in the C group and Ca1.70 group (P < 0.05). Concentrations of Ca and P in faeces increased with an increasing supplementation level of Ca and the highest concentrations were observed in the Ca1.70 group (P < 0.05). There were no differences in the concentrations of parathyroid hormone, alkaline phosphatase and osteocalcin among the treatments. Testosterone and oestradiol concentrations of the Ca1.7 group were higher than those of the C and Ca1.10 groups (P < 0.05). Average daily gains of fresh antler weight and dry antler weight of the groups Ca1.10 and Ca1.70 were greater than those of the C (P < 0.05). Fresh and dry antler yields of the Ca1.10 group were higher than those of the other groups (P < 0.05). In conclusion, optimal level of Ca supplement was found to be total Ca concentration of 1.10–1.70%, on the basis of DM, which significantly increased feed digestibility and antler daily gain for the 6-year-old sika deer.