Efeitos da dieta rica em caroço de algodão contendo gossipol na fertilidade de machos ovinos deslanados

Abstract

The gossypol is a Polyphenolic yellow pigment (C30H30O8), toxic that is present in all parts of cotton plant and its derivatives. Experiments show the reproductive side effects caused by feed containing high percentage of bran or cottonseed and claim that gossypol might affect in different ways the reproductive system, causing sperm abnormalities and subsequent infertility. In this work, it was examined the effects caused by diet rich in cottonseed containing gossypol on hair sheep ram semen Santa Inês Breed. The work was performed with 22 rams, sexually mature, which were divided into 2 groups, being the animals confined in individual stocks. The gossypol group (Gg = 15), was supplemented with 500g of gossypol cottonseed and the control group (Gc = 7), supplemented with 500g of corn. The two groups were supplemented during 104 days and underwent semen collections, by the method of artificial vagina and measurements of scrotal circumference (C.E.), before (7 days), during (at intervals of 15 days) and after (10 days) the supplementation period. Non o statistical difference was seen in the mean C.E. group being treatment and control group respectively 27.07 cm and 27.08 cm. The variable observed in the semen were: color, aspect, volume, whirling, motility, concentration, vigor and sperm morphology. For color and aspect analyses were qualitative and no differences were seen in these parameters. The mean for seminal volume for animals who consumed cottonseed was 1.04 ml and for control group was 0.94 ml with no significant difference. In the variable whirling, motility, vigor, concentration and morphology there was no statistical difference and the results was respectively 4.12-81.6%-4.26-3.57 x 109/ml sptz – 6.7% and 3.91 control group – 74.77%-4.07-3.48 x 109 sptz/ml-5.97%. After the last semen collection 5 animals from gossypol group and 2 animals from control group was submitted to unilateral orchiectomy. The material was used to perform the comparative Histopathological examination in historesin, No difference in seminiferous tubule diameter was seen between control and gossypol group. There was a significant difference in seminiferous epithelium height, having a larger measurement at gossypol epithelium compared with control group. The height of seminiferous epithelium is an effective feature for sperm production assessment, however in this study there was no significant difference in sperm concentration between control and treatment group demonstrating that this difference did not affect sperm production. Two out of the three castrated animals from gossypol group were used as a fertility test exposing them to 10 fertile ewes during 90 days, resulting in 6pregnancies. The results showed that supplementation with cottonseed gossypol rich-diet did not influence sperm quality, testicular morphology, fertilization capacity and seminiferous tubules morphology.