Evaluation of morphology, morphometry and follicular dynamics in FecGE genotyped ewes

Use of logistic models to evaluate the response of superovulation treatment and embryo production in Santa Inês ewes

The study aimed to verify the influence of the FecG^E mutation in superovulated ewes and to evaluate the probability of logistic models to determine the response capacity of these ewes to superovulatory treatment. Santa Inês ewes (n = 29) were genotyped for the FecG^E mutation and separated for their genotype group in carriers of the mutant E allele (FecG^E/E, FecG^+/E) and non-carrier (FecG^+/+) alleles. The ewes underwent hormonal treatment for superovulation. Aside from the genotypes, variables included in the statistical model were reproductive status (empty, early lactation, or late lactation), age (> or < 6 years), and number of births (nulliparous, primiparous, multiparous). The carriers of the mutation could be discriminated from the non-carriers based on the number of corpora lutea, rate of frozen embryos, and fecundity. Recovery rate was significantly higher (P < 0.05) in FecG^E/E (94.31%) compared to FecG^+/E (63.15%) and FecG^+/+ (61.90%) (P < 0.05), whereas fecundity rate of FecG^+/+ ewes (50.76%) was significantly higher than FecG^+/E (18.96%) and FecG^E/E (32.53%) (P < 0.05). We determined in this study that the response to superovulation and embryo production can be discriminated between FecG^E/E and FecG^+/E ewes in relation to the FecG^+/+ genotype. Logistic models that included reproductive status and mutation, or reproductive status and age, or reproductive status and number of births were effective in predicting the response to superovulatory treatment.

Occurrence, morphology, and morphometry of follicles containing multiple oocytes in FecGE mutant Santa Inês ewes

This study was conducted to characterize the morphology and morphometry of follicles containing multiple oocytes (MOFs) and determine the association with the FecG^E mutation in Santa Inês ewes. Based on the genotypes, 65 ewes were characterized as being homozygous wild-type (n = 25; FecG^+/+), heterozygous mutant (n = 27, FecG^+/E), and homozygous mutant (n = 13, FecG^E/E). The variables evaluated were follicle developmental stage, number of oocytes per follicle, morphology, and morphometry of MOFs. The FecG^E mutation did not affect the frequency of MOFs (P > 0.05) (3.0 % in FecG^+/+; 3.3 % in FecG^+/E; and 3.5 % in FecG^E/E). The greater viability (P < 0.05) of MOFs was identified in transitory stage of the FecG^E/E (95.0 %) and FecG^+/E (90.9 %) when compared to the FecG^+/+ genotype (73.3 %). Furthermore, the morphology of transitory follicles with two oocytes was the variable and when evaluated was the most reliable determinant for predicting which ewes had an FecG^E mutation. In conclusion, the FecG^E mutation did not affect the frequency of MOFs. The ewes with FecG^E mutation had a greater frequency of morphologically normal MOFs in the transitory stage. Furthermore, the ewes with the FecG^E mutation had a greater likelihood of having MOFs containing two morphologically normal oocytes.