Banca de DEFESA: WLAISA VASCONCELOS SAMPAIO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : WLAISA VASCONCELOS SAMPAIO
DATE: 12/05/2022
TIME: 09:00
LOCAL: Online via Google Meet
TITLE:

THE FATTENING PHENOMENON IN MALE SQUIRREL MONKEYS (Saimiri collinsi Osgood, 1916): FROM POST-COPULATORY SEXUAL SELECTION TO REPRODUCTIVE BIOMARKERS

KEY WORDS:

Fattening phenomenon; semen; neotropical primates; reproductive seasonality; mating season.

PAGES: 162
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Reprodução Animal
SPECIALTY: Ginecologia e Andrologia Animal
SUMMARY:

Free-living squirrel monkeys (Saimiri spp.) are considered strict seasonal breeders. During the mating season, males accumulate fat and water in their arms, shoulders, and chest, resulting in a characteristic weight gain known as the fattening phenomenon. The first studies associated the fatted condition with seasonal spermatogenesis and with increased seminal volume, motility, and sperm concentration. On the other hand, it is possible to obtain quality semen regardless of this condition in captivity, so the implications of this phenomenon on seminal quality and reproduction of the genus have not yet been fully understood. This study aimed to: (i) characterize and investigate the fattening phenomenon in Saimiri collinsi males and evaluate its implications for post-copulatory sexual selection; (ii) characterize the gonadosomatic index and evaluate its relationship with seminal quality, and determine the seasonal reproductive seasons based on this index; and (iii) to characterize the global and seasonal sperm subpopulations, and to evaluate their relationship with sperm quality. The experiment was conducted at the National Primate Center (latitude: 1º 22' 57" south, longitude: 48° 22' 52" west). Ten adult males (n = 10) were used, distributed in social groups, composed of adult males and females, infants, and juveniles. From June 2015 to July 2016, monthly, the animals were weighed, and the skinfolds of the arm and axilla, and testicular volume, were measured. Semen was collected by electroejaculation, all semen samples were evaluated for macroscopic parameters (volume, color, degree of coagulation, opacity, and pH) and microscopic parameters (motility, vigor, concentration, integrity, and functionality of plasma membrane, sperm morphology, and morphometry). The Fattening index was developed and provided the quantification of fattening with the accurate detection of inter and intra-individual variations. An improvement in seminal quality was observed when males exhibited the fatted condition. The seminal characteristics observed in the fatted male related to the protection and survival of sperm in the female reproductive tract were indicative of sperm competition, strengthening the hypothesis that the fatted male may be a product of post-copulatory sexual selection. The gonadosomatic index (GSI) was characterized, and the increase in weight implied in testicular enlargement, in which a positive correlation between testicular weight and weight, testicular volume, and GSI. The GSI showed a positive correlation only with seminal volume and cannot be used as a direct predictor of sperm function. Also, through this index, seasonal seasons in captivity were identified and an improvement in seminal quality was observed in the fattening season, corresponding to the highest values of the gonadosomatic ratio. Finally, the global and seasonal sperm subpopulations were determined by the morphometry of 7373 sperm. A seasonal effect on the size and shape of sperm heads and sperm quality was detected. Two subpopulations found in the fattening season showed characteristics of the final stages of sperm maturation and presented better sperm quality, being considered biomarkers of seasonal sperm quality. In this study, new tools were developed to assess sperm quality and the fattening phenomenon, which contributed to a better understanding of the reproductive physiology of male Saimiri collinsi.

BANKING MEMBERS:
Presidente - 480.204.273-68 - SHEYLA FARHAYLDES SOUZA DOMINGUES - UENF
Interno - 2121279 - LEANDRO NASSAR COUTINHO
Interno - 1305300 - FREDERICO OZANAN BARROS MONTEIRO
Externa à Instituição - PATRÍCIA DA CUNHA SOUSA - UFPA
Externo à Instituição - HELDER LIMA DE QUEIROZ - UFPA
Externa à Instituição - DANUZA LEITE LEAO - UFRA
Externo à Instituição - ALEXANDRE RODRIGUES SILVA - UFERSA