Parâmetros seminais e proteômica do plasma seminal de ovinos da raça santa inês alimentados com fonte alternativa de proteína

Abstract

The study was conducted with two objectives: 1) to analyze the protein composition of the seminal plasma of 8 Santa Inês rams fed with desolventized castor bean bran, using mass spectrometry associated with liquid chromatography (Study 1). 2) to determine the effect of diets on seminal parameters, sperm chromatin integrity and testicular dimensions of Santa Inês rams fed with industrially detoxified castor bean meal (Study 2). The rams were divided into three groups (FS - soybean meal, FMDP - sieved desolventized castor bean meal and FMD - desolventized castor bean meal) and the semen of all animals were collected through an electroejaculator in an interval of three days, after 77 days of feeding. In study 1, seminal plasma was separated from sperm cells, precipitated, quantified and the proteins were digested with trypsin, desalted and analyzed by LC-MS/MS. The peptide spectrum research allowed the identification of an average of 849 proteins in the study, confirming the BSPs (Binder Sperm Proteins) as the most abundant proteins. Data were analyzed using bioinformatics tools according to gene ontology, protein clustering, protein-protein interaction, metabolic pathways and miRNAs. It was possible to identify the main plasma proteins and proteins linked to toxicity and neurotoxicity, the main symptoms of castor bean poisoning. Therefore, a study is necessary to evaluate the effect of castor bean meal on seminal parameters to confirm whether soybean meal can be replaced by castor bean meal without compromising the fertility of rams. For study 2, after the collections, a semen volume was measured and the sperm concentration was determined with the aid of the Neubauer chamber. To analyze the percentage of motile sperm, a small fraction of semen was evaluated under an optical microscope and sperm morphology was evaluated using a formalin buffered saline solution. An aliquot of semen was used for the chromatin dispersion test to assess the integrity of the sperm DNA and the remaining semen, the pellet containing the ejaculated spermatozoa, was washed in a buffer and stored at -20° C. Seminal parameters and testicular dimensions analyzed in this study were not influenced by the diet, that is, soybean meal can be replaced by castor bean meal, without compromising the fertility of the animals.