Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Animal Production

The deleterious effect of heat stress on oocytes competence is well recognized in different species, the present study aimed to examine the effect of heat stress during oocyte maturation on the developmental competence of camel oocytes up to blastocyst stage and to investigate the efficiency of retinoid acid to alleviate heat stress during oocyte maturation. Immature camel COC were exposed to heat stress (41{u00B0}C and 42{u00B0}C) in different groups during the first 6 h of in vitro maturation, followed by 24 h of incubation at 38.5{u00B0}C. The control group entailedin vitro maturation at 38.5{u00B0}C for 30 h. Oocytes were activated with ethanol followed by 4 mM 6-DMAP and cultured in vitro for 7 days post parthenogenetic activation. The first experiment was run on six groups, A total of 1548 oocytes were used in this experiment divided into six groups. The groups were named as K1 (good quality oocytes incubated at 38.5oC for 30 h), K2 (low quality oocytes incubated at 38.5oC for 30 h), K3 (good quality oocytes exposed to 41oC for the first 6 hof maturation, and then cultured at 38.5oC for 24 h), K4 (good quality oocytes exposed to 42oC for the first 6 hof maturation, and then cultured at 38.5oC for 24 h), K5 (low quality oocytes exposed to 41oC for the first 6 hof maturation and then cultured at 38.5oC for 24 h), and K6 (low quality oocytes exposed to 42oC for the first 6 h of maturation and then cultured at 38.5oC for 24 h). The second experiment was run on five groups, heat stressed good quality Immature camel COC at 42oC were exposed to culture media with 0, 5, 10 and 20 æM of retinoid acid. The groups were named as K7 (exposed to an incubation temperature of 38.5{u00B0}C in IVM0), K8 (was exposed to an incubation temperature of 42{u00B0}C in IVM0), K9, K10 and K11, was exposed to 42{u00B0}C in IVM1, IVM2 and IVM3 respectively. The results of this study indicated that heat stress at 42oC significantly decreased the Pb rate in K4 and K6 compared to other groups. After parthenogenesis, the development rate was significantly lower for good and low quality oocytes exposed to heat stress (K3, K4, K5, and K6) compared with K1 and K2

Issued also as CD