|Support type:||Scholarships in Brazil - Scientific Initiation|
|Effective date (Start):||August 01, 2013|
|Effective date (End):||July 31, 2014|
|Field of knowledge:||Agronomical Sciences - Veterinary Medicine - Animal Reproduction|
|Principal Investigator:||Eneiva Carla Carvalho Celeghini|
|Grantee:||Tamie Guibu de Almeida|
|Home Institution:||Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil|
The frozen ram semen has been object of large studies, considering that, his using makes possible the use of artificial insemination (AI) on sheep although, the pregnancy rate achieved through IA has still been short, probably, dues to the necessity of spermatozoids thawed overcome the cervical barrier which opens opportunity of searching for greater knowledge of the semen to be frozen. Supplementation with vitamin A helps in renovation of seminiferous epithelium and decreasing of concentration of reactive oxygen species; on the other hand, the use of low intensity laserterapia (LT), which encourages the cellular mitosis, could also serve as an aid in the proliferation of seminiferous epithelium and thus contributing to obtain better indices in freezing semen. This project aims to analyze the ram semen freezability, submitted or not to testicular degeneration, supplemented with vitamin A or low intensity lasertherapy. Eighteen sheep will be used and distributed into six treatments groups: 1) control: no degenerated and no treated (n=3), 2) no degenerated and supplemented with vitamin A (n=3), 3) no degenerated and submitted to lasertherapy (n=3), 4) degenerated and no treated (n=3), 5) degenerated and supplemented with vitamin A (n=3), 6)degenerated and submitted to low intensity lasertherapy (n=3). During the experimental period weekly assessment will be made including: reproductive exam, evaluation of testicular and rectal temperature. Soon, after harvest, semen will be evaluated increased by extender base of egg, packaged in plastic straws and cryopreserved, using an automated system, being kept in cryogenic cylinders (-196º C). Then, the semen straw will be thawed (37ºC/30 seconds) and evaluated for motility (CASA), sperm morphology (DIC), integrity of plasma and acrosomal membranes, mitochondrial function and oxidative stress. The data will be submitted to analysis of variance and the averages compared by Fisher's test employing the statistical program, Statistical Analysis System (SAS Institute Inc., 2004).