Effect of heat-stress on bovine embryo development in vitro.
Chronic elevation of uterine temperature has long been known to increase embryo mortality in dairy cattle. Short-term elevation in temperature of mouse embryos to 43 degrees C (acute) has been shown to induce intracellular production of heat-shock proteins. In this study, in vitro development of bovine embryos was assessed during short-term (60 h) coculture with oviduct epithelial cells at 38.6 degrees C (T1), 40 degrees C (T2), 38.6 degrees C after a prior pulse treatment (20 min) at 43 degrees C with 5% CO2 (T3), or 38.6 degrees C after a prior pulse treatment (20 min) at 43 degrees C with 100% CO2 (T4). During incubation, embryos cocultured at 40 degrees C had a greater (P < .05) mean embryo development score at 36 h than embryos cocultured at 38.6 degrees C. At 60 h of incubation, embryo development scores were greater (P < .05) for embryos cultured at 38.6 degrees C than for those cocultured at 40 degrees C. The number of embryos hatched at 60 h was similar after coculture at 38.6 degrees C (T1) or a prior pulse treatment with 5% CO2 and 43 degrees C (T3), but the embryo development score at 60 h was greater (P < .05) for the pulse-treated embryos. Embryos in T4 had greater (P < .05) embryo development scores than did T1 embryos from 36 through 60 h. Pulse treatment (T4) resulted in a greater (P < .05) number of hatched embryos at 60 h than T1, T2, and T3. These results indicate a detrimental effect of a chronic elevation in temperature that was evident shortly after embryo hatching.(ABSTRACT TRUNCATED AT 250 WORDS)
Ryan
D P
DP
Department of Animal Science, Louisiana State University Agricultural Center, Baton Rouge 70803.
Blakewood
E G
EG
Lynn
J W
JW
Munyakazi
L
L
Godke
R A
RA
D000818:Animals; D002417:Cattle / Q000196:embryology*; D002478:Cells, Cultured; D003470:Culture Media; D015232:Dinoprostone / Q000096:biosynthesis; D005314:Embryonic and Fetal Development; D005187:Fallopian Tubes / Q000166:cytology; D005260:Female; D006041:Goats; D006358:Hot Temperature / Q000009:adverse effects*; D066298:In Vitro Techniques; D009028:Morula / Q000502:physiology*; D011897:Random Allocation
D003470:Culture Media; D015232:Dinoprostone