Rekwot P I, Oyedipe E O, Dawuda P M, Sekoni V O
Artificial Insemination Unit, National Animal Production Research Institute, Ahmadu Bello University, Zaria, Nigeria.
Vet J. 1997 May;153(3):341-7. doi: 10.1016/s1090-0233(97)80068-8.
Serum testosterone concentrations and the spermiograms of prepuberal bulls fed two levels of protein diets were investigated at 7, 10, 14 and 18 months of age. Scrotal circumference, body condition score and total sperm counts of those animals on a high protein diet were significantly (P < 0.05) higher than those on a low protein diet. However, sperm motility, total dead sperm and abnormal sperm did not differ between the treatment groups (P < 0.05). One bull fed a high protein diet had significantly higher testosterone concentrations (basal and peak) than a bull fed low protein throughout the four sampling periods (P < 0.05). Testosterone concentrations, scrotal circumference, volume of semen, sperm concentration and sperm output of bulls on low and high protein diets increased significantly with age (P < 0.05). Peak testosterone concentrations ranged from 1.1 ng ml-1 at 7 months to a maximum of 5.3 ng ml-1 at 18 months. The 24 h secretory patterns of testosterone were episodic, pulsatile or temporal in nature. The peaks occurred mostly in the morning hours and ranged from one to five in number. Protein intake in prepubertal bulls could have significant influence on spermiogram and testosterone production.
对饲喂两种蛋白质水平日粮的青春期前公牛，在7、10、14和18月龄时测定其血清睾酮浓度和精子图谱。高蛋白日粮组动物的阴囊周长、体况评分和精子总数显著（P<0.05）高于低蛋白日粮组。然而，处理组之间的精子活力、总死精和畸形精子无差异（P<0.05）。在整个四个采样期，饲喂高蛋白日粮的一头公牛的睾酮浓度（基础值和峰值）显著高于饲喂低蛋白日粮的公牛（P<0.05）。低蛋白和高蛋白日粮公牛的睾酮浓度、阴囊周长、精液体积、精子浓度和精子产量均随年龄显著增加（P<0.05）。睾酮峰值浓度从7月龄时的1.1 ng/ml到18月龄时的最高5.3 ng/ml不等。睾酮的24小时分泌模式呈间歇性、脉冲性或随时间变化。峰值大多出现在上午，数量从1到5个不等。青春期前公牛的蛋白质摄入量可能对精子图谱和睾酮产生有显著影响。
