Effect of recipient doe genotype.on survival rate at birth of frozen rabbit embryos

Abstract

Summary -The effect of the genotype of 2 selected rabbit strains (White New Zealand and Synthetic) on the survival rate at birth of frozen embryos was studied. Morulae were obtained 64-66 h postcoitum from 32 multiparous does naturally mated with males of the same strain (16 does of Synthetic strain (SY) and 16 does of the White New Zealand strain (NZ)). Morphologically normal morulae were slowly frozen in 1.5 M DMSO and stored in liquid nitrogen. After thawing, intact embryos from both strains were transferred into the oviducts of 32 recipient does of both strains (16 SY strain does and 16 NZ does). Significant differences were observed in pregnancy rate and survival rate at birth between strains of recipient does. The recipient does of the SY strain showed a higher pregnancy rate than those of the NZ strain (87.5% versus 25% respectively; P < 0.05). When the survival rate at birth was analyzed in all recipient does, this was found to be 28 ± 4% in SY recipient does versus 8 ± 4 % in NZ recipient does (P< 0.01). However, when the survival rate was analyzed in pregnant recipient does, no significant differences were found between embryo strains and recipient strains, the average survival rate was 32%. The major factor in the differential survival rate between SY and NZ embryos was due to the genotype of recipient does.

Effect of rabbit line on a program of cryopreserved embryos by vitrification

“…In accordance with previous studies [16], all recipient does were multiparous does belonging to line V and ovulation was induced in receptive does (red vulvar lips) 60-64 h before transfer with an intramuscular dose of 0.8 µg buseriline acetate (Hoescht).…”

Embryo Manipulation Techniques in the Rabbit

“…The success of the vitrification-thawing procedures depends on the concentration and composition of the vitrification solution, the cooling and thawing conditions, the procedure used to dilute embryos from the vitrification solution, and the volume of the vitrification solution [70]. The genotype of the embryo and the genotype of the recipient female also affect the efficiency of the vitrification-thawing procedure [71].…”

“…On one hand, at least two foeto-placental units are required to maintain the gestation [114,115], and on the other hand, when the survival rate is high, competition between foetuses can lead to a lower foetal survival [115]. So, the number of transferred embryos recommended per recipients ranges between 10 and 13 for both fresh and cryopreserved embryos [71,116]. If the number of transferred embryos per donor female is lower than this range, it is possible Embryos are graded following the Veeck and Maloney criterion.…”

“…New Insights into Theriogenology to transfer embryos from two donor females to each of the uterine horns of the recipient female, to ensure the survival of the embryos [71]. In case it is necessary to know the origin of the transferred embryos, it is recommended to perform a caesarean to the recipient female [71].…”

“…New Insights into Theriogenology to transfer embryos from two donor females to each of the uterine horns of the recipient female, to ensure the survival of the embryos [71]. In case it is necessary to know the origin of the transferred embryos, it is recommended to perform a caesarean to the recipient female [71]. In general, asynchrony is obtained by artificially inducing ovulation in recipient female between 0 and 6 h before the donor females, for fresh embryos, or between 6 and 12 h before, for in vitro cultured or cryopreserved embryos [60,65,70,113].…”