Relação do tempo de armazenamento dos espermatozoides no oviduto de peruas com a fertilidade e desenvolvimento embrionário

Abstract

This study aimed to determine the relation between the sperm storage time in the oviduct of turkey hens with fertility and embryo development. The experiment was conducted on a Nicholas 700 strain breeding turkeys’ farm, in Uberlândia. A group of 140 turkeys hens, with 54 weeks old, was maintained without insemination during 30 days. After this period, the females were all inseminated on the same day with diluted fresh semen, from a group of males with the same age. During the following 30 days, no other insemination was performed. At this period, the eggs were collected between 7am and 6pm, every 40 minutes and stored in a room under 19ºC of temperature. Half of the eggs was sent every 02 days to the laboratory for analysis of sperm holes in the inner perivitelline layer on the germinal disc region and the other half, referred to the hatchery. The eggs were divided into three groups of two to six days (G1), seven to 20 days (G2) and 21 to 30 days (G3) after insemination, totalling around 1500 eggs collected. During incubation, the following assessments were performed: fertility at 14 days after incubation (%), hatchability (%) and embryonic mortality stages (%). The average sperm holes number in the inner perivitelline layer was analyzed by Kruskal-Wallis test (α = 0.05). To verify the relation between the sperm storage time in the oviduct of turkey hens with fertility and embryo development, the linear correlation test (α = 0.05) was performed between the variables evaluated. There was a statistically significant difference for the analysis of sperm holes in the inner perivitelline layer over the days after insemination. The sperm storage time showed a positive and significant correlation with embryo mortality at second and fourth stages of embryonic development and negative and significant with fertility at 14 days and hatchability. The number of sperm holes showed a significant positive correlation only with fertility after 14 days of incubation. The number of sperm holes in the inner perivitelline layer seven days after insemination demonstrates the necessity of weekly inseminations, so there is no loss in reproductive efficiency. The positive correlation between the number of sperm holes and fertility demonstrates that this methodology is effective for the fertility assessment. The positive correlations between the storage time and embryonic mortality in the second and fourth stages, and negative with the hatchability, show that besides reducing fertility, the long sperm storage time in the oviduct of turkey hens also provides changes in sperm cells that do not interfere with their fertilizing capacity but interfere with the embryo formation.