Super-ovulation In Animals Research Articles

Modulation of Gonadotropins Activity by Antibodies.

Gonadotropins are essential for reproduction control in humans as well as in animals. They are widely used all over the world for ovarian stimulation in women, spermatogenesis stimulation in men, and ovulation induction and superovulation in animals. Despite the availability of many different preparations, all are made of the native hormones. Having different ligands with a wide activity range for a given receptor helps better understand its molecular and cellular signaling mechanisms as well as its physiological functions, and thus helps the development of more specific and adapted medicines. One way to control the gonadotropins' activity could be the use of modulating antibodies. Antibodies are powerful tools that were largely used to decipher gonadotropins' actions and they have shown their utility as therapeutics in several other indications such as cancer. In this review, we summarize the inhibitory and potentiating antibodies to gonadotropins, and their potential therapeutic applications.

Effect of corifollitropin alfa supplemented with or without LH on ovarian stimulation and embryo viability in rabbit

There is increasing interest in using rabbits for research as a laboratory model as well as for industrial production of meat, wool and fur. Superovulation in animals is used to produce a maximum number of transferable embryos per donor, in order to either support genetic improvement programs, ex situ conservation or to optimize other biotechnologies. Over time, the use of this biotechnology has shown variable outcomes as a consequence of several factors, such as the origin of exogenous hormone, posology and the effect of gonadotropins used simultaneously, the donor and the environment. The aim of this study was to compare the efficacy of a single injection of corifollitropin alfa (CTP), alone or supplemented with LH, versus a FSH standard protocol of five equal doses administered twice daily to superovulate rabbit does (20 per group and 29 control females). We determined: 1) the impact of this stimulation on in vitro development and mRNA expression at blastocyst stage and 2) in vivo embryo development and viability rate at birth of transferred embryos. Our outcomes showed that the ovulation rate was similar among the different ovarian stimulation groups, reaching more than fourfold the ovulation rate of a control doe. While rates of embryos developing to the blastocyst stage after 48 h of in vitro culture were similar between groups, the hatched blastocyst rate was higher for superovulated embryos from CTP group. Moreover, no significant differences among mRNA expression of OCT4, SOX2 and NANOG genes were detected. Nevertheless, embryos from ovarian stimulated does with CTP + LH showed significantly higher implantation rates and survival at birth among the different ovarian stimulation groups and similar to those in the control group. In conclusion, the results of this study suggest that a single injection of long acting corifollitropin alfa can be effectively used in rabbits to elicit a more than fourfold increase in ovulation rate compared to control animals. In addition, the LH supplementation allows us to obtain similar in vivo embryo development results as in the control group.

25 TIMED ARTIFICIAL INSEMINATION ENABLES HIGH FERTILIZATION RATES IN NORMAL CYCLING AND IN SUPEROVULATED CATTLE WITH REDUCED DOSAGES OF UNSORTED SPERMATOZOA AND WITH SEXED SPERMATOZOA

Different factors determine the effectiveness of the use of sires in AI. Most important factors are the number of inseminated spermatozoa, the quality of spermatozoa, and the time of insemination. Especially in superovulated animals, the insemination scheme plays in important role to cover the whole ovulation period. The influence of 3 different dosages of spermatozoa (15 × 106, 5 × 106, and 1 × 106) on fertilization rate was examined in experiment A. In experiment B, one dosage of female and male spermatozoa of 3 different bulls was used for timed AI in 31 heifers. Timed AI in normal-cycling cattle [13 h after gonadotropin-releasing hormone (GnRH) application] with detected corpus luteum (Days 8 to 13 of cycle) was carried out after induction of luteolysis and induction of ovulation [GnRH application 60 h after prostaglandin F2α (PGF2) application]. Embryos and oocytes were flushed from the oviduct of 116 hemicastrated or slaughtered heifers on Day 4 after insemination. The ovulation rate in heifers was 95.4%. Eighty percent of the oocytes or embryos were recovered. The influence of the factors sire, ejaculate, and dosage were tested by GLM analyses of SAS® (SAS Institute Inc., Cary, NC, USA). There was no significant difference in the fertilization rate (93.3, 96.2, and 78.8%) and in the proportion of normally developed embryos (84.6, 80.7, and 75.8%) between groups. Significant differences were found in the mean number of accessory sperms/embryo and in the proportion of embryos with >10 accessory sperms/embryo or without accessory sperms; however, the proportion of intact embryos was similar. Using sexed semen in experiment B, similar results were obtained after flushing of the oviducts on Day 4 after insemination of hemicastrated or slaughtered animals. In total, an ovulation rate of 91.7%, a recovery rate of 70%, and a fertilization rate of 86.8% were obtained. There were no differences between female- and male-sorted spermatozoa and the control group. In experiment C, altogether 13 heifers were treated 8 times with FSH for 4 days starting between Day 8 to 12 of estrous cycle. Prostaglandin F2α was given 48 and 60 h after the first FSH injection. Insemination with sexed semen (n = 5 heifers) and with unsorted semen (n = 8; 15 × 106 and 1 × 106) was done at 55 and 71 h after induction of luteolysis. Flushing of the uterus was performed on Day 7. Using the time-oriented insemination after superovulation of animals, fertilization rates varied between 65 and 85%. There was no difference between groups regarding the number of transferable embryos (5.5, 4.9, and 4.8). The results demonstrate that the application of an approved insemination schedule may accomplish high fertilization rates after insemination with sexed or reduced dosages of spermatozoa in normal-cycling as well as superovulated cattle.

Relationships between the ovarian status and superovulatory responses in dairy cattle

The aim of this study was to determine the influence of follicular profiles over 4 days prior to superovulation on superovulatory responses. Eighty-eight Holstein cows were synchronized by two prostaglandin F2α injections given 11 days apart and conventionally superovulated between days 8 and 12 of the estrous cycle with 400mg Folltropin-V given in decreasing doses over 4 days. Luteolysis was induced by 2 im injections of cloprostenol (2ml) with the sixth and seventh injections of Folltropin-V. The ovaries of all cows were examined by ultrasonography with a real-time linear scanning ultrasound diagnostic system (Ls-300-A: Tokyo Keiki Co., Tokyo, Japan; 7.5MHz Transducer) on days −3, −2, −1, 0 (initiation day of the superovulatory treatment=day 0). Data were analyzed by the GLM procedure of the SAS. Animals with a greater diameter of the largest follicle (F1; 13.4 vs 9.8 and 10.1mm; p<0.007) and with a greater difference in the diameter of the first and second largest follicles (7.6 vs 4.5 and 3.8mm; p<0.001) had the greater superovulatory response and produced the greater number of quality I embryos. In conclusion, the diameter of the F1 and the F1–F2 follicles were higher over a 4-day period prior to superovulation in animals yielding a high than a medium and a low number of quality I and I+II embryos.

The effect of Syncro-Mate-B ear implant and estradiol treatment on superovulatory response in the cow

The aim of this study was to determine the influence of follicular profiles over 4 days prior to superovulation on superovulatory responses. Eighty-eight Holstein cows were synchronized by two prostaglandin F2α injections given 11 days apart and conventionally superovulated between days 8 and 12 of the estrous cycle with 400 mg Folltropin-V given in decreasing doses over 4 days. Luteolysis was induced by 2 im injections of cloprostenol (2 ml) with the sixth and seventh injections of Folltropin-V. The ovaries of all cows were examined by ultrasonography with a real-time linear scanning ultrasound diagnostic system (Ls-300-A: Tokyo Keiki Co., Tokyo, Japan; 7.5 MHz Transducer) on days −3, −2, −1, 0 (initiation day of the superovulatory treatment = day 0). Data were analyzed by the GLM procedure of the SAS. Animals with a greater diameter of the largest follicle (F1; 13.4 vs 9.8 and 10.1 mm; p < 0.007) and with a greater difference in the diameter of the first and second largest follicles (7.6 vs 4.5 and 3.8 mm; p < 0.001) had the greater superovulatory response and produced the greater number of quality I embryos. In conclusion, the diameter of the F1 and the F1–F2 follicles were higher over a 4-day period prior to superovulation in animals yielding a high than a medium and a low number of quality I and I + II embryos.

Different methods of synchronizing embryo transfer donor cows

The aim of this study was to determine the influence of follicular profiles over 4 days prior to superovulation on superovulatory responses. Eighty-eight Holstein cows were synchronized by two prostaglandin F2α injections given 11 days apart and conventionally superovulated between days 8 and 12 of the estrous cycle with 400 mg Folltropin-V given in decreasing doses over 4 days. Luteolysis was induced by 2 im injections of cloprostenol (2 ml) with the sixth and seventh injections of Folltropin-V. The ovaries of all cows were examined by ultrasonography with a real-time linear scanning ultrasound diagnostic system (Ls-300-A: Tokyo Keiki Co., Tokyo, Japan; 7.5 MHz Transducer) on days −3, −2, −1, 0 (initiation day of the superovulatory treatment = day 0). Data were analyzed by the GLM procedure of the SAS. Animals with a greater diameter of the largest follicle (F1; 13.4 vs 9.8 and 10.1 mm; p < 0.007) and with a greater difference in the diameter of the first and second largest follicles (7.6 vs 4.5 and 3.8 mm; p < 0.001) had the greater superovulatory response and produced the greater number of quality I embryos. In conclusion, the diameter of the F1 and the F1–F2 follicles were higher over a 4-day period prior to superovulation in animals yielding a high than a medium and a low number of quality I and I + II embryos.