THE MALE CONTRIBUTION TO BROILER BREEDER HEAT-INDUCED INFERTILITY AS DETERMINED BY SPERM-EGG PENETRATION AND SPERM STORAGE WITHIN THE HENS OVIDUCT

The purpose of the present study was to define the role of the male br oiler breeder in heat-induced infertility. Seventy-two Arbor Acres roo sters were individually caged at 21 wk of age and divided equally amon g three heated (I-I) and three control (C) temperature chambers. Contr ol temperature chambers were held at 21 C. After an 8-wk pretreatment period (20 C), an 8-wk treatment period was conducted in which the tem perature in all three of the H chambers was varied from week to week a ccording to the following schedule: Week 1, 27 C; Week 2 through Week 4, 32 C; and Week 5 through Week 8, 21 C. On a weekly basis, semen was pooled by room and inseminated into 12 groups of 10 hens each (2 grou ps per room). During the Ist wk when males were maintained at 27 C for 12 h, in vivo sperm-egg penetration was reduced by 48% as compared to data obtained when males were maintained at 21 C. Fertility, in viva sperm-egg penetration, and uterovaginal sperm storage were decreased w hen semen from males exposed to 32 C was used to inseminate hens as co mpared to insemination with semen from C males. However, during this s ame period, the ability of sperm to bind to and penetrate the egg, as determined by in vitro sperm-egg penetration, was similar between sper m from C and H males. After lowering the temperature in the I-I chambe rs back to 21 C, in vivo sperm-egg penetration as a result of insemina tion with semen from H males was analogous to results obtained when C males were used for insemination. Immediately after decreasing the tem perature in the H chambers, fertilization of eggs by sperm from H male s increased to a level similar to that obtained when eggs were fertili zed by sperm from C males but then declined again during the later wee ks.