Desempenho produtivo, características seminais e morfométricas do testículo de coelhos alimentados com farelo de canola (Brassica sp.) até 180 dias de idade

• Autor(a) principal: Santos, Lígia Vieira Lage dos
• Data de Publicação: 2006
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1810
• topic: Coelho; Reprodução; Canola; Glicosinolatos; Sêmen; Sangue; Testículo; Desempenho; Rabbits; Reproduction; Canola; Semen; Blood; Testis; Performance; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

This study investigated if the goitrogenic potential of anti-nutritional substances present in canola meal could cause alterations in the performance, semen and testicular morphometry of rabbits. For this, the crude soy meal protein of the diet was completely substituted for canola meal, making up a diet with 18% of crude protein. For the performance and blood parameter studies, the animals were evaluated from 90 to 120, 120 to 150 and from 150 to 180 days old. The rabbits were initially divided in two treatments (T): TS (soy treatment) and TCanC (continuous canola treatment). The live weight, weight gain, feed consumption and conversion were measured from 60 to 90, from 90 to 150 and from 150 to 180 days old. Starting from 150 days, another treatment was created, the TCanI (interrupted canola treatment), which consisted of the canola diet being interrupted and substituted by the soy diet. Performance data from 60 to 150 days showed that the applied treatment influenced all of the observed variables, with greater values being observed in the TCanC animals. However, the feed conversion was less for this treatment. From 90 to 150 and from 150 to 180 days old, differences were not observed for the studied variables. Within the analyzed organs, a reduction in the hepatic weight was only observed in the TCanC at 180 days old, without affecting the TS or TCanI animals, which showed an intermediary value between TCanC and TS. The glucose concentration, total cholesterol, triglycerides, urea and T3 blood studies showed that glucose concentrations were only affected by the treatment (P<0.05) at 180 days, with the greater value for TS animals, and no difference was found between TCanC and TCanI. For cholesterol, the treatment resulted in a significant effect at 150 and 180 days. The minimum value was found for TS animals, in both ages (P<0.05). Trigliceride levels were only affected by the treatment at 150 days. The larger concentration was observed in TCanC (P<0.05). For urea, the treatment only interfered at 180 days. The minimum concentration was found in the TS animals (P<0.05). The triiodothyronine hormone (T3) was present in a greater concentration in the animals fed with canola (TCanC and TCanI) than those that received soy (TS), at 150 and at 180 days. For the seminal and morphometric parameters of the testicles, 5 treatments were evaluated: rabbits fed with soy meal (TS) or with canola meal during gestation (TCanIBth canola treatment interrupted at birth), up to weaning (TCanWn canola treatment interrupted at weaning), up to puberty (TCanIPu canola treatment interrupted at puberty) or until adult stage is reached (TCanC continuous canola treatment). Starting from 120 days old, semen was colleted every 10 days, for the evaluation of fresh volume, motility, vigor and aspect, as well as concentration and spermatic pathologies. At 150 and 180 days, ten animals from each treatment were separated for the removal and weighing of the testicles, epididymis and accessory glands. The left testicles were fixed for histologic processing and the morphometric study. In the seminal analyses, the treatment comparisons showed a difference (P<0.05) at 140 days old for vigor between TS x TCanIWn and between TCanIWn x TcanBth animals. There was a linear effect for motility (P<0.05), for all treatments over time, except in TCanIPu. TCanC showed more spermatic motility than the others (P<0.05). Volume showed a linear effect (P<0.05) over time for TS and TCanC, with the largest volume observed in TS and the smallest in TcanIPu animals. The concentration showed (P<0.05) a quadratic effect for TCanID and TCanC, but the TS and TCanIPa were less concentrated than TCanID and TCanC. The sperm minor defects were not affected by treatments (P>0.05); but the major defects, showed a quadratic effect (P<0.05) for all the treatments, except TCanIWn. The morphometric analyses, testicle, epididymis and accessory gland weights, the seminiferous tube width and the epithelia thickness were similar for all treatments (P>0.05). About the volumetric proportions (%) and volume (mL) of the testicular components, only the lymphatic space proportion of the TCanC was smaller (P<0.05) than the other treatments animals, but this difference was not observed for the volume of this component. The gonadossomatic index was similar (P>0.05) among the treatments and the two ages. It is concluded that the glucosinolates present in canola meal did not affect the rabbits performance, metabolism or morphometric and quantitative alterations in the testicles or their reproductive physiology, up to the evaluated age. Its use for longer periods should be evaluated.