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Ovulation rates in donor mares treated with purified equine FSH
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Theriogenology
OVULATION RATES IN DONOR MARES TREATED WITH PURIFIED EQUINE FSH B. Remy’, J.F. Bruyas’v J.F. Beckers’, F. Leduc 2, F. Fieni ‘, D. Tainturie? l- ISRIA - Faculty of Veterinary Medecine, Sart Tilman, B 4000 LIEGE - BELGIQUE 2- Nantes Veterinary School - BP 40706 - 44307 NANTES Cedex 03 - FRANCE The aim of this study was to test the efficacy of eFSH purified from horse pituitaries to induce multiple ovulation in mares. Equine gonadotropins were isolated from pituitary glands by using amonium sulfate precipitation, ions exchange and hydrophobic chromatographies, FSH and LH activities were monitored in specific radioreceptor assays based on bovine receptors and highly purified hormones (Beckers, Theriogenology, 1987,27,213). At the sixth day of the cycle, mares were injected with PGF2a analog (cloprostenol 25Oltg) to induce estrus. Mares were treated on 4 successive estrus cycles (cross over trials). Treatment began on the day of PGF2ct injection. Mares received either daily intramuscular injection of eFSH (750 pg) or placebo until a single ovulations or two or more preovulatory follicles (2 33 mm) were obtained. In this case, 5 mg of eLH were injected to induce synchronous ovulations. Serial treatments were eFSH, placebo, eFSH, placebo in group 1 (2 pony mares, 3 trotters mares) and placebo, eFSH, placebo, eFSH in group 2 (3 pony mares, 3 trotter mares). Mares were artificially inseminated (AI) with fresh semen from the same fertile pony stallion once growing follicles reached 33 mm of diameter, and AI were continuing every other day until ovulation occurred. Nonsurgical embryo collections were performed 6 days after ovulation. Binary results (success of superovulation = yes or no) were analysed by MC Nemar test and quantitative results were analysed by t Student test for cross-over trial. The table summarizes the results: Table 1: Mean ovulation and embryo collection data from mares treated with eFSH or placebo. eFSH treated cycles Control (placebo) cycles (n=22) (n=22) 10.18 [4- 181 10.57 [5-171 Mean number of days of treatment [range] Mean no of preovulatory follicles/donor [range] 1.81* [l-3] 1.13* [l-2] Mean number ovulations/donor [range] 1.09* [O-2] 1.59* [O-3] Number of cycles with multiple ovulations (12) 1l/22 ** l/22 ** Mean number embryos/donor [range] 0.47 [O-3] 0.19 [O-l] Mean number embryos/ovulations 0.26 (9/33) 0.22 (5/23) Values with the same superscript, in the same line are significantly different : * (P < 0.05) ** (P < 0.001) Equine FSH treatment did not modify the time of the follicular growth but increased the ovulation rate and induced double or triple ovulations in 50% of cycles. Nevertheless, the ovulation rate obtained with this eFSH treatment was lower than those reported with Crude Equine Gonadotropin treatments (Dieppert et al., Theriogenoly, 1992,38,695- 710). This lower response can be explained by a relatively low dose of FSH or by a relatively low amount of LH in this FSH. The embryo recovery rate per collection tended to be higher after treatment than after control cycles. The embryo recovery rate per ovulation was not different between control and treated cycles, but was lower (22 and 26 %) than the one usually obtained after non- treated cycles in the same herd of mares (40 to 60%) (unpublished results). In other reports about ovarian stimulation in mares, the embryo recovery rate per ovulation was lower for the treated group than untreated control group (without placebo) (Douglas, Theriogenology, 1979, 11, 33-46, Dieppert et al., Theriogenoly, 1992, 38, 695- 710, Palmer et al., Equine Vet. J., 1993, Suppl 13, 99-102). The stress due to repeated injections may explain the poor results in term of superovulatory response and of embryo recovery. Other trials must be carried out in order to determine otpimal eFSH dose.
Theriogenology
OVULATION RATES IN DONOR MARES TREATED WITH PURIFIED EQUINE FSH B. Remy’, J.F. Bruyas’v J.F. Beckers’, F. Leduc 2, F. Fieni ‘, D. Tainturie? l- ISRIA - Faculty of Veterinary Medecine, Sart Tilman, B 4000 LIEGE - BELGIQUE 2- Nantes Veterinary School - BP 40706 - 44307 NANTES Cedex 03 - FRANCE The aim of this study was to test the efficacy of eFSH purified from horse pituitaries to induce multiple ovulation in mares. Equine gonadotropins were isolated from pituitary glands by using amonium sulfate precipitation, ions exchange and hydrophobic chromatographies, FSH and LH activities were monitored in specific radioreceptor assays based on bovine receptors and highly purified hormones (Beckers, Theriogenology, 1987,27,213). At the sixth day of the cycle, mares were injected with PGF2a analog (cloprostenol 25Oltg) to induce estrus. Mares were treated on 4 successive estrus cycles (cross over trials). Treatment began on the day of PGF2ct injection. Mares received either daily intramuscular injection of eFSH (750 pg) or placebo until a single ovulations or two or more preovulatory follicles (2 33 mm) were obtained. In this case, 5 mg of eLH were injected to induce synchronous ovulations. Serial treatments were eFSH, placebo, eFSH, placebo in group 1 (2 pony mares, 3 trotters mares) and placebo, eFSH, placebo, eFSH in group 2 (3 pony mares, 3 trotter mares). Mares were artificially inseminated (AI) with fresh semen from the same fertile pony stallion once growing follicles reached 33 mm of diameter, and AI were continuing every other day until ovulation occurred. Nonsurgical embryo collections were performed 6 days after ovulation. Binary results (success of superovulation = yes or no) were analysed by MC Nemar test and quantitative results were analysed by t Student test for cross-over trial. The table summarizes the results: Table 1: Mean ovulation and embryo collection data from mares treated with eFSH or placebo. eFSH treated cycles Control (placebo) cycles (n=22) (n=22) 10.18 [4- 181 10.57 [5-171 Mean number of days of treatment [range] Mean no of preovulatory follicles/donor [range] 1.81* [l-3] 1.13* [l-2] Mean number ovulations/donor [range] 1.09* [O-2] 1.59* [O-3] Number of cycles with multiple ovulations (12) 1l/22 ** l/22 ** Mean number embryos/donor [range] 0.47 [O-3] 0.19 [O-l] Mean number embryos/ovulations 0.26 (9/33) 0.22 (5/23) Values with the same superscript, in the same line are significantly different : * (P < 0.05) ** (P < 0.001) Equine FSH treatment did not modify the time of the follicular growth but increased the ovulation rate and induced double or triple ovulations in 50% of cycles. Nevertheless, the ovulation rate obtained with this eFSH treatment was lower than those reported with Crude Equine Gonadotropin treatments (Dieppert et al., Theriogenoly, 1992,38,695- 710). This lower response can be explained by a relatively low dose of FSH or by a relatively low amount of LH in this FSH. The embryo recovery rate per collection tended to be higher after treatment than after control cycles. The embryo recovery rate per ovulation was not different between control and treated cycles, but was lower (22 and 26 %) than the one usually obtained after non- treated cycles in the same herd of mares (40 to 60%) (unpublished results). In other reports about ovarian stimulation in mares, the embryo recovery rate per ovulation was lower for the treated group than untreated control group (without placebo) (Douglas, Theriogenology, 1979, 11, 33-46, Dieppert et al., Theriogenoly, 1992, 38, 695- 710, Palmer et al., Equine Vet. J., 1993, Suppl 13, 99-102). The stress due to repeated injections may explain the poor results in term of superovulatory response and of embryo recovery. Other trials must be carried out in order to determine otpimal eFSH dose.