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.

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The efficiency of an embryo bank depends on provision of optimal conditions for recovery, cryopreservation and transfer to a breed or strain. In this sense, increasing the number of embryos available using superovulation should improve the cryobank efficiency. However, vagueness of response to conventional protocols to control or increase ovarian response and the quality of oocytes and embryos and their cryotolerance remain a challenge. The aim of our study was to evaluate the effect of corifollitropin alpha (CTP) and a recombinant human FSH (rhFSH), alone or supplemented with rhLH, on embryo cryosurvival by in vitro development and OCT4 and NANOG mRNA abundance at blastocyst stage and offspring rate. In vitro development of vitrified embryos was not significantly affected by superstimulation with or without rhLH supplementation, resulting in similar development rates to those of the control groups (fresh and vitrified embryos from non-superstimulated donor does). Blastocysts developed from vitrified embryos showed higher levels of OCT4 transcript abundance than fresh control, while NANOG transcript abundance was only higher in the blastocysts developed from vitrified embryos after superstimulation treatment in comparison with control groups. The implantation and offspring rates at birth were negatively affected by supplementation with rhLH. Both rhFSH or CTP vitrified embryo groups showed an implantation rate similar to those of the control groups, but an offspring rate lower than control. In conclusion, embryos produced using corifollitropin alpha did not compromise the cryosurvival of vitrified embryos in the rabbit. In addition, this study points out the negative effect of rhLH supplementation in terms of offspring rate on embryo vitrification.

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This study aimed at assessing farmers’ perceptions and acceptance of the proposed breeding strategy of Instituto Veterinario de Investigaciones Tropicales y de Altura (IVITA), located in the Central Andes of Peru. A total of 34 farmers, who had received guinea pigs from IVITA, were interviewed. The questionnaire was performed in Spanish language and covered topics about the guinea pig production, feeding, mating system, training, the main products, perception and acceptance of crossbred lines (“cuy RG”), and the farmers’ comment about the terminal crossbred animal (“cuy G”). The preferred feeding strategy was a combination of forage and supplement. All farmers implemented a controlled mating system. Most farmers had received training on feeding, reproduction, management, equipment, and facilities. The main product is animals for slaughter. The 82.40% of farmers reported that they do not purchase guinea pigs from IVITA anymore, because they are highly susceptibility to lymphadenitis, which is a highly contagious disease and causes swollen lymph nodes and affects the meat quality. Most of the respondents classified the “cuy RG” and “cuy G” as suitable for meat production and were satisfied with the performance of the animals. Therefore, 58.80% of respondents already recommended “cuy RG” to other farmers. However, 17.70% of the respondents would not recommend these animals because they are susceptible to disease, especially lymphadenitis. Therefore, IVITA should engage in more structured dialogue with farmers and regularly include their opinion in future improvement of its breeding strategies. This could help to reach higher acceptance rates by farmers.