Fertilization rates and embryonic development in CD-1 mice fed fungal endophyte-infected tall fescue seed.

The objective of this study was to assess the effects of endophyte-infected tall fescue (KY-31) seed (80% infected, containing Acremonium coenophialum ) on the fertilization rates and embryonic development of CD-1 mice. Twenty-four pairs of mature CD-1 mice were randomly allocated to two dietary treatments containing 40% mouse chow and 1) 60% noninfected tall fescue seed or 2) 60% infected tall fescue seed (w/w). The mice were preconditioned on their respective diets for 60 d prior to 96 h of cohabitation between pairs of males and females. Following the removal of the males, equal numbers of females (n = 4) from each dietary treatment were sacrificed at 80 h, 6 and 10 d after vaginal plug establishment. The female reproductive tracts were excised and flushed to recover eggs and embryos or dissected to identify the number and status of the implanted fetuses. The number of eggs-embryos and/or fetuses per mouse present at the time of sacrifice were 9.8, 8.8 and 11.5 vs 8.2, 5.3 and 4.8 for the mice fed the noninfected and infected fescue seeds, respectively. Similarly, the conception rates (%) were 100, 100 and 100 vs 73, 50 and 50 for the two treatments. The mice sacrificed at 80 h and fed the noninfected fescue had 9.8 expanded blastocysts per animal, whereas those fed the infected fescue had only 4.0 expanded blastocysts. The results suggest that the infected fescue seed consumed by these mice had a significant effect on fertilization rates. More importantly, the infected fescue seed influenced negatively the development of these embryos during the embryonic-preimplantation period.