Effects of FecB Mutation on Estrus, Ovulation, and Endocrine Characteristics in Small Tail Han Sheep

Abstract

The Booroola fecundity gene (FecB) has a mutation that was found to increase the ovulation rate and litter size in Booroola Merino sheep. This mutation is also associated with the fecundity of small-tail han (STH) sheep, an important maternal breed used to produce hybrid offspring for mutton production in China. Previous research showed that the FecB gene affects reproduction in STH sheep, based on litter size records. However, the effects of this gene on estrus, ovulation, and endocrine characteristics in these sheep remain unclear. Here, we analyzed the traits mentioned earlier and compared them among the three FecB genotypes of STH ewes using estrus synchronization. Overall, 53 pluriparous ewes were selected from among 890 STH ewes and subjected to FecB genotyping for experiments to characterize estrous and ovulation rates. FecB heterozygous (+B) ewes presented an earlier onset of estrus (42.9 ± 2.2 h) and a shorter estrous cycle (17.2 ± 0.2 days) (P ≤ 0.05). The ovulation rates increased with the increasing copy number of the B allele (P ≤ 0.01). Ovulation time showed no significant differences among the three FecB genotypes. The serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone, estrogen (E2), and progesterone (P4) were measured in 19 of the ewes. Serum concentrations of E2 and FSH dramatically varied around the time of behavioral estrus. In FecB mutant homozygous (BB) ewes, E2 concentration had two peaks, which were higher (P ≤ 0.05) than those of ++ genotypes. FSH concentration of BB ewes was higher (P ≤ 0.05) than that of the ++ ewes just after estrus. The expression of the estrogen receptor 1 (ESR1) gene in the +B genotype was higher than in the other genotypes. Based on the data for the reproductive performance of STH ewes with the three FecB genotypes, our study suggests that the development of follicles in ewes with the B allele is dependent on the response to FSH regulated by E2 in the early stage. +B ewes, exhibiting moderate ovulation and litter size and a shorter estrous cycle, can be highly recommended in sheep crossbreeding systems for commercial mutton production. Moreover, this study provides useful information to conserve better and use the genetic resources of STH sheep in China.

Insight Into Pituitary lncRNA and mRNA at Two Estrous Stages in Small Tail Han Sheep With Different FecB Genotypes

“…Firstly, ewes were treated with vaginal sponges (300 mg progesterone; InterAg Co., Ltd., Hamilton, New Zealand), followed by injection of vitamin AD to protect the endometrium. The vaginal sponges were evacuated after 12 days, and the removal time was set as 0 h. In accordance with previous reproductive trait analyses, six ewes (three BB and three WW ewes) were euthanized at 45 h (follicular phase) and six ewes (three BB and three WW ewes) at 216 h (luteal phase) ( 30 , 31 ). Pituitary samples were dissected immediately after euthanasia, frozen in liquid nitrogen, and stored at −80°C for further analysis.…”

Effect of melatonin on ATG2B‐mediated autophagy regulation in sheep granulosa cells with different FecB genotypes

“…Fec B is a major effect gene associated with the lambing number trait in sheep, which has been used as a crucial molecular marker for selecting high-fertility sheep. [1][2][3][4][5][6] Studies have shown that Fec B has an additive effect on the ovulation rate, with effects on litter size ranging from additive to dominant depending on the genotype. 7 However, the molecular mechanism of Fec B mutation in the regulation of lambing number traits in sheep remains unclear.…”

“…Increasing the number of lambs produced by sheep is fundamental to the availability of sheep products. Fec B is a major effect gene associated with the lambing number trait in sheep, which has been used as a crucial molecular marker for selecting high‐fertility sheep 1–6 . Studies have shown that Fec B has an additive effect on the ovulation rate, with effects on litter size ranging from additive to dominant depending on the genotype 7 .…”

Are Copy Number Variations within the FecB Gene Significantly Associated with Morphometric Traits in Goats?

“…The Booroola fecundity gene ( Fec B ), also known as the bone morphogenetic protein receptor-1B (BMPR1B) gene, is the first major gene discovered that is related to sheep fertility [ 1 , 2 , 3 , 4 , 5 ]. Fec B is also involved in granulosa cell differentiation, follicle development, and ovulation in sheep [ 6 , 7 ].…”