Spermatogenesis in sheep supplemented with detoxified castor bean (Ricinus communis L.) as a replacement for soybean meal

ABSTRACT The objective was to evaluate the effect of replacing soybean meal with the detoxified castor bean cake on testicular morphometry and spermatogenesis of sheep. Were used 24 uncastrated, 9-month old sheep weighing 29±0.8 kg they were randomly distributed among three treatments: T1 = 0%, T2 = 50%, and T3 = 100% substitution of soybean meal with detoxified castor bean cake. The animals were fed with Aruana grass pastage (Panicum maximum ‘Aruana’) and a ration for 90 days. After slaughtering, the testicles were collected and histological slides were prepared with tissue fragments. The data were evaluated for normality using the Shapiro-Wilk test, and analysis of variance was carried out at 5% level of significance. Substitution of soybean meal with detoxified castor bean cake had no effect on any of the assessed variables at the tested levels (P >0.05). The mean yield of spermatogenesis was 72.91 rounded spermatids per spermatogonium; the mean of total number of germ cells held by a Sertoli cell was 12.09; the mean of the testicular spermatic reserve was 31.82×109 and that per testicular gram was 238.28×106; the mean of daily spermatic production was 3.03×109 and that per testicular gram was 22.69×106; and the total number of Sertoli cells was 4.15×109 and that per testicular gram was 34.51×106. The results show that it is possible to replace 100% of the soybean meal with detoxified castor bean cake in sheep diet without any effects on spermatogenesis; however, it is important to perform seminal evaluations in future studies.

摘要 本研究旨在评估以脱毒蓖麻饼替代豆粕对绵羊睾丸形态计量学及精子发生的影响。选取24只体重为29±0.8 kg的9月龄未去势绵羊，随机分为3个处理组：T1组（以脱毒蓖麻饼替代0%豆粕）、T2组（替代50%豆粕）及T3组（替代100%豆粕）。所有试验羊均饲喂阿鲁安娜草（大黍*Panicum maximum* ‘Aruana’）与配合日粮，试验周期为90天。试验羊屠宰后采集睾丸，取组织片段制作组织学切片。采用Shapiro-Wilk检验对数据进行正态性检验，并以5%为显著性水平开展方差分析。在本试验设置的替代水平下，以脱毒蓖麻饼替代豆粕对所有测定指标均无显著影响（P>0.05）。每精原细胞的平均精子发生产量为72.91个圆形精子细胞；每个支持细胞（Sertoli cell）所承载的生殖细胞总数平均值为12.09；睾丸精子总储量为31.82×10⁹，每克睾丸组织的精子储量为238.28×10⁶；每日精子生成量为3.03×10⁹，每克睾丸组织的日精子生成量为22.69×10⁶；支持细胞总数为4.15×10⁹，每克睾丸组织的支持细胞数为34.51×10⁶。研究结果表明，在绵羊日粮中以脱毒蓖麻饼完全替代豆粕，不会对精子发生产生不良影响；但在后续研究中开展精液评估仍具有重要意义。