Growth response, organ morphometry, sperm production and reserve in rabbit bucks administered carrot fruit extracts

An experiment was conducted for 12 weeks to investigate the anti-oxidative effect of carrot fruit extracts administered to rabbit bucks on growth, organ characteristics, gonadal and extra-gonadal sperm reserves, and daily sperm production. A total of 35 rabbit bucks (four months old with average weight of 1.62±0.2kg) were randomly allotted into treatment groups each containing seven bucks per replicate. The bucks were subjected to the same environmental conditions and were assigned into five doses of carrot fruit extracts administration: Treatment 1 (0 mL of carrot fruit extracts (CE)/kg BW i.e. control), treatment 2 (0.5 mL CE/kg BW), treatment 3 (1.0 mL CE/kg BW), treatment 4 (1.5 ml CE/kg BW), treatment 5 (2 mL CE/kg BW). The extract was administered by drenching using corn oil as the carrier. The bucks were weighed weekly to determine weight gain and feed conversion ratio. At the end of the trial, the bucks were sacrificed, dissected, organs removed and weighed. Testes and epididymis were homogenised and filtered. The sperm cells in the testicular and epididymal homogenates were determined. Organ characteristics: eviscerated weight, adrenal gland, liver, lungs, kidney, pancreas, bile, testis, spleen, heart and GIT weight were measured. Data were subjected to analysis of variance at P = 0.05. The bucks administered with 1.0 mL CE had the highest relative eviscerated weight (48.74±6.73%) and also recorded the highest weight gain (0.21±0.15g/day) when compared to other treatments. There was non-significant difference for most of the organs assessed except for the GIT and spleen weight. The GIT weight was significantly (P<0.05) higher in T1 (15.41%), T3 (14.81%) and T4 (16.23%) than T2 (13.58) and T5 (13.09%) in rabbits administered 0.5mL and 2.0mL CE/kg BW, respectively. Relative spleen weight of rabbits administered 0.2mL CE/kg BW was similar to T1 but significantly (p<0.05) higher than T2, T3 and T4. Testicular and epididymal sperms reserves significantly (P<0.05) increased as the concentration of the carrot fruit extract administered to rabbits increased. Daily sperm production was significantly (P<0.05) higher in treated bucks than the control bucks. This study suggests that administering carrot fruit extracts up to 2mL/kg body weight increased growth, sperm cell production and testicular sperm reserve. Keywords: Carrot fruit antioxidants, sperm reserve, daily sperm production, rabbit