BIOLOGY OF MALE AND FEMALE GAMETES
7:30 AM-10:00 AM
(164) THE EFFECTS OF SCROTAL INSULATION ON SPERM MORPHOLOGY AND IN VITRO FERTILIZATION.
Enwall, Lefric1, Ostermeier, G.3, Sartor Bergfelt, Renata1, Laplante, Lindsey1, Kaya, Abdullah2, Parrish, John1, 1 Dept of Animal Sciences, Madison, WI3 School of Medicine, Detroit, MI2 Dept of Reproduction and Artificial Insemination, Konya, TR
ABSTRACT- The effect of scrotal insulation for 48 hr on bull sperm morphology as assessed by Fourier harmonic analysis and in vitro fertility as assessed by ability of sperm to penetrate oocytes, the ratio of oocytes cleaved at 32/48 hr post insemination, and number of nuclei after 135 hr of culture. Analysis of sperm morphology used a quality control chart approach comparing semen collections obtained before and at 2 to 3 day intervals after scrotal insulation (ASI). The sum of the Fourier harmonic amplitude variances were used as measures of the variation in sperm nuclear shape. The variation in sperm nuclear shape increased (p<0.05) for collections (days ASI)) with sperm that were undergoing epididymal transit (day 2) and spermiogenesis (day 14), meiosis (days 42 and 47) at the time of insulation. These changes in nuclear shape variation would be indicative of reduced fertility. When examining the in vitro fertility of the same semen samples, no effect was found on fertilization. Timing of first cleavage was evaluated as faster cleaving embryos are more likely to develop to the morula/blastocyst stage. The ratio of cleavage at 32/48 hr was decreased (p<0.05) for collections (days ASI) with sperm undergoing epididymal transit (day 2), spermiogenesis (day 14, 23), meiosis (days 30, 33, 35, 37, 47) and spermatocytogenesis (days 49, 61 and 66) at the time of insulation. The number of nuclei in embryos after 135 hr of culture were reduced for collections (days ASI) from 19±1 nuclei (day 0) to 13±2 (day 14) and 16±2 (day 26). There were effects on sperm in vitro fertility for sperm undergoing all stages of development at the time of scrotal insulation. The Fourier harmonic analysis identified a variety of changes to the variation in sperm shape but it was best able to identify changes in sperm at days 2, 14 and 47 that were related to reduced in vitro fertility. In particular, day 14 sperm undergoing spermiogenesis had increased variation in shape, delayed time to first cleavage, and reduced number of nuclei by 135 hr of culture. Supported by USDA 98-02163.
KEY WORDS: nuclear, shape, fertility, bovine