ASSOCIATION OF ANTHROPOMETRICAL INDEX, REPRODUCTIVE PARAMETERS AND REPRODUCTIVE HORMONAL LEVELS IN MALE GREATER CANE RAT (THRYONOMYS SWIN DERIAN US)

摘要

Anthropometric parameters and their relationship with reproductive and hormonal parameters have been useful tools in predicting the effect of increased fat deposition on reproduction and general well-being in man. This study examined this interrelationship in the greater cane rat, a hystricomorphic herbivorous rodent that is currently undergoing domestication in parts of Africa.The body mass and Lee indices (BMI and LI), which are two most commonly used fat estimation parameters were characterized and their linear relationships with testicular and epididymal morphometric parameters as well as with serum concentrations of five sex hormones were analyzed in seventy-two sexually matured cane rats over a period of one year. Six animals, kidded and raised on a farm, with known ages and reproductive history were used each month. The experimental protocols entailed body measurements of weight, height and length; testicular and epididymal measurements of volume and weight; histology; and hormonal immunoassay of testosterone, estradiol, progesterone, luteinizing (LH) and follicle stimulating (FSH) hormones using their various kits. For the cane rat, the average testicular weight and volume were 1.43 ±0.40g and 1.33 ±0.26cm~3 and for epididymis, 0.33 ±0.03g and 0.23 ±0.03 cm~3, while the mean values for BMI and LI were 1. 18±0.20g/ cm~2 and 0.30±0.02g/cm respectively. With normal histo-architecture, no significant correlation exists between BMI/LI and testicular parameters, but a relationship existsbetween these indices and epididymal weight (BMI: r~2=0.38; LI: r~2=0.29). Also, of all the five hormones, only estradiol concentration has a low correlation with BMI/LI (r~2 = 0.2). Knowledge of this interrelationship can help in breeding selection andaid in mitigating possible risk factors like obesity in the greater cane rat.