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Endocrine Profiles and Embryo Quality in Japanese Black Cattle Superovulated with Human Menopausal Gonadotrophin and Porcine Follicle Stimulating Hormone
Author(s) -
Sugano M,
Shinogi T,
Nakada K,
Nakao T
Publication year - 2001
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1046/j.1439-0531.2001.00192.x
Subject(s) - follicle stimulating hormone , medicine , endocrinology , hormone , embryo , menotropins , endocrine system , biology , embryo quality , andrology , luteinizing hormone , ovulation , embryogenesis , ovulation induction , microbiology and biotechnology
Induction of superovulation using human menopausal gonadotriphin (hMG) in Japanese Black cattle can result in the recovery of a higher percentage of high quality embryos compared with that using porcine follicle stimulating hormone (FSH). In order to clarify the endocrinological mechanism involved in this discrepancy, 30 superovulation sessions of 17 Japanese Black cattle were studied. Fifteen cattle were super‐stimulated with hMG (total 600 IU), and the remaining 15 cattle were given FSH (total 20 mg). The plasma profiles of LH, estradiol‐17β (E 2 ) and progesterone (P 4 ) were correlated, and the embryo quality was investigated. The total number of ova recovered and the number of transferable embryos tended to be larger in the hMG‐treated group than in the FSH‐treated group. The percentage of excellent embryos tended to be higher in the hMG‐treated group than in the FSH‐treated group (54.3 and 28.7%, respectively, p < 0.10). The E 2 level increased during the first 3 days after the initial administration of either hMG or FSH and was higher in the hMG‐treated group than in the FSH‐treated group (p < 0.05). During this period, the E 2 level could be categorized into one of the following three types according to whether it increased or decreased and according to the degree of increase or decrease: (1) increase by a factor of 1.2 or more (quick increase type) (2) slight increase by a factor less than 1.2 (slow increase type), and (3) no increase (unstable increase type). In the group treated with hMG, 66.7% of the animals (10 of 15 cattle) showed a quick increase in the E 2 level. However, in the FSH‐treated group, 40% (six of 15) of the animals showed a slow increase in the E 2 level. The plasma LH level increased dramatically 8 h prior to the peak level in both the hMG‐ and FSH‐treated groups, and then it returned to the basal level 12 h later. After the administration of prostaglandin (PG)F 2α , the LH peak level was attained within 44 h in 80% of the animals in the hMG‐treated group, whereas in the FSH‐treated group, the LH peak level tended to be reached later. The P 4 level did not increase during the period of hMG or FSH treatment and decreased drastically following administration of PGF 2α . After the onset of oestrus, the P 4 level was higher in the hMG group than in the FSH group, and 5 to 7 days after oestrus, the level remained higher in the hMG group than in the FSH group (p < 0.05). After the first 3 days of hMG administration, the E 2 /P 4 ratio was higher than that after FSH administration. Furthermore, on the day following PGF 2α administration, the ratio was significantly higher in the hMG group than in the FSH group (p < 0.05). These results indicate that superovulation in cattle given hMG results in a significant increase in plasma E 2 during the first 3 days and that the increase in the plasma P 4 level is larger a few days after oestrus and thereafter compared with FSH‐induced superovulation. Therefore, such plasma level profiles may be related to the increased recovery rate of high quality embryos.