The effects of feeding graded levels of whole cottonseed on semen characteristics and testicular profiles of Red Sokoto Bucks

ABSTRACT. The present work evaluated the effects of feeding graded levels of whole cottonseed on reproductive parameters of Red Sokoto bucks. Twenty Red Sokoto bucks were used for the experiment. After a 14-day pre-treatment period, bucks were assigned for 90 days to one of four isonitrogeneous treatments: control (diet A); 0 mg kg-1 of total gossypol, (diet B); 15% mg kg-1 of total gossypol, (diet C); 30% mg kg-1 of total gossypol and (diet D); 45% mg kg-1 of total gossypol. The mean percentage sperm gross motility was significantly (p < 0.05) lower in group D (45% WCS) compared to groups C (30% WCS) and A (control) at days 60, 75 and 90. The mean semen pH and reaction time were not significantly (p > 0.05) different among treatment groups. Semen colour of the bucks in the control group was majorly creamy, in group C (30% WCS) and B (15% WCS) creamy to milky and group D (45% WCS) colourless. The mean semen volume was significantly (p < 0.05) higher in groups C and A compared to group D (45% WCS) at days 60, 75 and 90. The mean semen concentration was significantly (p < 0.05) lower in group D (45% WCS) when compared to group A (control) at days 30, 45, 60, 75 and 90. Group A (control) bucks had significantly (p < 0.05) higher percentage live sperm compared to those in group D (45% WCS) at days 45, 60, 75 and 90. Mean Sperm morphological abnormalities including detached head, free tail curved tail and midpiece droplets were significantly (p < 0.05) higher in group D (45%) than in group A (Control) at day 15 (for free tails) and day 90 (for all). Testicular and epididymal sperm reserves were higher in animals supplemented with up to 30% whole cottonseed. In conclusion, feeding bucks above 30% WCS resulted in more deleterious effects on the semen characteristics and testicular profile.

摘要。本研究评估了饲喂梯度剂量全棉籽（whole cottonseed, WCS）对红索科托公山羊（Red Sokoto bucks）繁殖性能参数的影响。本实验选用20只红索科托公山羊，经14天预处理期后，将其随机分为4组等氮日粮处理组，试验周期为90天：对照组（日粮A）；总棉酚（total gossypol）含量0 mg·kg⁻¹组（日粮B）；总棉酚含量15 mg·kg⁻¹组（日粮C）；总棉酚含量30 mg·kg⁻¹组（日粮D）；总棉酚含量45 mg·kg⁻¹组。在试验第60、75和90天时，D组（45%全棉籽组）的精子总活率显著低于C组（30%全棉籽组）与对照组（A组）（p < 0.05）。各处理组的精液pH值与反应时间均无显著差异（p > 0.05）。对照组公山羊的精液颜色多为乳脂色，C组（30%全棉籽组）与B组（15%全棉籽组）的精液颜色为乳脂色至乳白色，D组（45%全棉籽组）精液呈无色。在试验第60、75和90天时，C组与对照组的精液平均体积显著高于D组（45%全棉籽组）（p < 0.05）。在试验第30、45、60、75和90天时，D组（45%全棉籽组）的精子平均浓度显著低于对照组（A组）（p < 0.05）。在试验第45、60、75和90天时，对照组（A组）公山羊的精子活率显著高于D组（45%全棉籽组）（p < 0.05）。在试验第15天（游离尾部异常）及第90天（所有形态异常类型）时，D组（45%全棉籽组）的精子平均形态异常率（包括头部脱落、游离尾部、弯曲尾部及中段滴）显著高于对照组（A组）（p < 0.05）。饲喂最高30%全棉籽日粮的公山羊，其睾丸及附睾内的精子储备量更高。综上，给公山羊饲喂超过30%全棉籽的日粮，会对精液品质及睾丸相关指标产生更显著的有害影响。