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Effects of photodynamic therapy on spermatozoa and seminal microorganisms from domestic roosters

Grant number: 17/04457-6
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): June 01, 2017
Effective date (End): December 31, 2017
Field of knowledge:Agronomical Sciences - Veterinary Medicine - Animal Reproduction
Principal Investigator:Ricardo Jose Garcia Pereira
Grantee:Gabriel Augusto Novaes
Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil


Agribusiness plays an essential role in Brazilian economy through the generation of jobs and income, in addition to food production and distribution for the entire population. In this regard, poultry industry emerges as key economical player since Brazil became the second largest global producer and the world's biggest exporter of chicken meat in 2015, generating revenue of US$ 7.167 billion. Therefore, biotechnology innovations that enhance poultry breeding are highly relevant due to their potential in reducing costs and adding more value to the final product. Artificial insemination (AI) is a good example of such aptitude, considering the economical, genetic and health benefits that this method may offer to the production chain. However, it is not rare that poultry ejaculates exhibit high levels of microorganism since cloaca is a common pathway for semen, urine and feces. In an attempt to control this contamination many semen extenders used in birds have antibiotics in their formula, an approach that have been lately challenged by some researchers because of its implications regarding bacterial resistance. Thus, aiming to create alternatives to the use of antibiotics, our study intends to investigate the impact of photodynamic therapy (PDT) on spermatozoa and seminal bacteria. To this end, semen samples from adult roosters (Lohmann LSL) will be initially diluted with extenders containing different concentrations of photosensitizer (methylene blue - 5, 10, 15, 20 and 25 mM) and then will be exposed to different exposure times using a red LED (»= 660 ± 15 nm) with irradiance of 100 mW/cm2. After defining which protocols interfere less with sperm viability, a second experiment will be performed to investigate the effects of these treatments on seminal bacteria. Our long-term goal is to determine a PDT protocol capable of reducing bacterial contamination without damaging spermatozoa, generating a technique that may finish the use of antibiotics in poultry semen extenders. (AU)