Suplementação com torta de dendê (Elaeis guineensis) sobre parâmetros reprodutivos de cordeiros a pasto

Abstract

This study aimed to assess the effects of different levels of palm kernel cake on reproductive performance in Santa Inês rams. A total of 40 animals with a starting age of 5 months and mean body weight of 24,10±2,72 kg were assigned in completely randomized design to four treatments and 10 replicates, with levels of palm kernel cake in the concentrated diet: 0; 15; 30 and 45% based on dry matter. The animal were kept in individual stalls by morning to acess concentrate supplements offered at 1,5% body weight with adjustment at fortnightly intervals based on liveweights, and grazing in Massai grass whole day. The trial lasted 90 days foregone by 15 days for adaptation. Blood chemistry parameters were measured in blood serum sampled every 45 days from jugular vein after 12 hours of food restriction, using 9mL vacutainer tube containing no anticoagulant. The samples were kept at 5oC and then centrifuged at 3500 x g for 15 minutes. Total serum cholesterol, triglycerides, high density lipoproteins, low density lipoproteins and very low density lipoproteins in the control and the test groups were assessed.Semen samples were collected by electroejaculator once for a week for three sequence weeks, and assessed for volume, color, aspect, wave motion, motility, sperm concentration, motility, vigor sperm and sperm morphology. The scrotal circumference was recorded with a cloth tape and measured as the largest diameter of the testes and scrotum after pushing the testes firmly. Scrotal length and width of all rams were recorded with a vernier caliper every fifteen days. Animals were slaughtered at 35,24±4,41 kg of mean liveweight and the testis were collected and preserved in the ice pack for histologic proceedings to morphometric assess. Dissected testis were measured with a sensitive weighing balance calibrated in grams. The data were subjected to Shapiro-Wilk and Levene’s test to verify homogeneity of variances and normality respectivally.Then were performed analysis of variance using the General Linear Model. Multiple regression equations were developed for the different levels of palm kernel cake.For data that were not normally distributed, the diet effect were analysed by Kruskal-Wallis nonparametric tests using SAS software.The total cholesterol, high density lipoprotein, triglycerides and very low density lipoprotein wereaffected (P<0,05)by the diet with linear increase effect.Furthermore, the diets affected (P<0,05) sperm concentration and minor defects but did not affected (P>0,05) other seminal characteristics. There was no difference (P>0,05) in testicular biometric parameters, however there was a decreasing linear behavior in percentage and volume blood vessels. The diets affected (P<0,05) volume of the seminiferous tubules and gonadosomatic index with quadratic effect. The other morphometric variables did not affected (P>0,05) by palm kernel cake. It was concluded that the inclusion of palm kernel cake up to 45% of dry matter concentrate improves rams reproductive performance and could be used as alternative resource for sheep.