Effect of organic selenium supplementation on growth, reproductive performance and nutrient digestibility in matured Boer bucks

A study was conducted to determine the effect of organic Selenium (Se) supplementation on growth, reproductive performance and nutrient digestibility in matured Boer bucks. The feeding trial was conducted at MARDI Bachok Station, Bachok, Kelantan over six months period while the digestibility trial was carried out at the MARDI Jeram Pasu Station, Pasir Puteh, Kelantan for five days. A total of 18 matured Boer bucks aged of 2 years with the initial body weight of 53.28±0.62 kg and no experience of sexual activity were selected for the feeding trial. For the digestibility trial, 9 matured Boer bucks of 2 years age with the initial body weight of 31.67±0.60 kg were selected. All animals were randomly divided into three dietary treatments based on a completely randomized design (CRD). Group A and B were supplemented with 0.3 mg Se/kg DM and 0.6 mg Se/kg DM, whereas group C acted as a control group (without Se supplementation). Their basal diet consisted of 60% formulated pellet and 40% Brachiaria dictyoneura grass of 6 weeks age. Daily feed offered (on dry matter basis) was based on 3% of mean body weight. During the feeding trial, body weight changes, libido, scrotal circumference and sperm quality were measured every two months. Serum Ca, P, Cu, Se and testosterone concentrations were determined at the end of the feeding trial. The results indicated that both Brachiaria dictyoneura grass and pellet were deficient in Se, with concentrations of 0.001 mg/kg and 0.006 mg/kg, respectively. Supplementation of 0.3 Se/kg DM and 0.6 mg Se/kg DM through Se yeast over six months feeding period did not affect appetite and any health problem on the animals. Supplementation of 0.6 mg Se/kg DM had significantly (P<0.05) increased live weight, ADG and FCE, as well as serum Se concentration. These are attributed to significant enhancement (P<0.05) in the digestibility of ash, CP, EE, CF, ADF, NDF, Ca, Cu and Se. Percentage balance of CP, P, Ca, Cu and Se were also improved significantly (P<0.05). Additionally, reproductive performance of the goats was also improved (P<0.05) based on an increase in libido, scrotum circumference, sperm quality and testosterone concentration. Supplementation of 0.3 mg Se/kg DM did also improved sperm quality (P<0.05). It is summarized that supplementation of 0.6 mg Se/kg DM over a minimum period of 6 months has the potential to improve growth and reproductive performance of matured buck in Malaysia.