Expression of apoptosis and myogenesis related genes during prenatal life in two divergent breeds of pigs.

We aimed to evaluate apoptosis and myogenesis related genes expression in embryos and fetuses from two divergent genetic groups of pigs: Piau breed and a commercial line. Thirty females (15 Piau and 15 commercial line) were selected at 120 days of age. Estrous cycle was observed and on the third estrus females were considered sexually mature. Gilts were inseminated with semen from males of the respective breed. Three females from each breed were slaughtered at five different gestational ages: 15, 30, 45, 60 and 90 days. Whole embryos (15 and 30 d) and samples of longissimus dorsi muscle from fetuses (45, 60 and 90 d) were collected for RNA extraction. Expression of apoptosis and myogenesis related genes (BAX, BCL2, FGF4, IHH, HHIP, SHH, SOX2, WNT1 and WNT4) were evaluated by quantitative real time PCR. There was significant effect of interaction between breeds and gestational ages for all genes evaluated (P < 0.05). The BCL2 gene expression differed throughout pregnancy in Piau group with lower expression on day 15. The IHH gene expression throughout pregnancy was lower on days 15 and 60 in Piau group and lower on day 90 in commercial line group; and the SHH gene expression throughout pregnancy was higher on day 30 and lower on day 60 in Piau group and lower on day 45 in commercial group. The WNT1 gene expression along pregnancy was lower on day 15 and higher on days 30 and 45 in Piau group, and it was higher on day 30 than days 15 and 60 in commercial group. WNT4 gene expression throughout pregnancy was lower on day 15 in Piau group, and it was lower on day 30 in commercial pigs. Piau group presented higher expression of the FGF4 gene on days 45, 60 and 90, and commercial group showed higher expression on day 15 and 90. SOX2 gene expression was lower on day 15 in Piau pigs and it was constant throughout pregnancy in commercial group. Overall, the expression of IHH, SHH, WNT1, WNT4 and FGF4 genes were higher in commercial than Piau pigs on day 15, besides expression of BCL2 gene in Piau embryos was lower on day 15; these results might indicate that the muscle precursor cells are allowed to proliferate for a longer time in commercial than in Piau embryos by the balance of proliferative and apoptotic genes. Therefore, the expression differential between breeds can stimulate proliferation and differentiation of cells in different ways, explaining the postnatal differences in the muscularity between pigs from Piau breed and a commercial line.

Dietary L-arginine supplementation during early gestation of gilts affects conceptuses development.

l-arginine supplementation of sows has led to improvement of reproductive performance, but the mechanisms responsible for the positive effects of arginine during gestation on conceptuses survival and development are still poorly understood. Thus, we aimed to evaluate effects of 1.0% l-arginine supplementation (ARG) on phenotypic traits of commercial gilts, embryos and fetuses, concentration of gilts' blood metabolites, expression of developmental and cellular apoptosis genes in conceptuses of 25 and 35 days. At 25 days, IGF1 gene was more expressed in embryos from ARG than in embryos from control gilts (CON) (P = 0.05). At this same gestational age, ARG embryos tended to be heavier compared to CON (P = 0.07) and ARG gilts showed a trend to have a greater arginine concentration in blood plasma (P = 0.06). However, at 35 days of gestation, arginine concentration in blood plasma of ARG gilts tended to be lower compared to CON (P = 0.06) and ARG fetuses showed smaller cephalic-caudal length (P = 0.05). These results indicate that duration of supplementation is determinant for arginine effects, not only on the females performance but also on the conceptuses, since supplementation upregulated IGF1 expression at 25 days, in addition to the reduction of cephalic-caudal length of 35-day fetuses.

Genes expression and phenotypic differences in corpus luteum and cumulus cells of commercial line and piau breed gilts.

We aimed to characterize the expression of angiogenesis-related genes in corpus luteum (CL) and cumulus cells (CC) during estrous cycle in gilts of different genetic groups, as well as to study the relation between gene expression and phenotypic data. Forty five gilts were used as follows: L1, Commercial Line 1 (Large White x Landrace x Duroc) (n = 15); L2, Commercial Line 2 (Large White x Landrace x Pietrain) (n = 15); and Piau, Piau breed gilts (n = 15). Estrus observation started from 120 days of age. After the second observed estrus females were slaughtered (n = 3) on days 3, 5, 10, 14 and 18 of estrous cycle (first day of estrous cycle as Day 0). CL sampling was performed on days 3, 5, 10 and 14 and collection of CC and follicular fluid on days 14 and 18. Follicular fluid was used for analysis of estradiol levels and CC and CL samples for analysis of angiogenesis-related genes expression, ANGPT-1/-2 and TEK in CC and MMP-2, VEGFA, VEGFR-1/-2, ANGPT-1/-2 and TEK in CL. Piau gilts showed lower ovulation rate than both L1 and L2 gilts (P < 0.05), lower number of large antral follicles (>6 mm) at 18 days than L2 gilts (P < 0.05), and smaller diameter of the largest follicles at 14 days than L1 gilts (P < 0.05). Piau and L2 gilts showed higher estradiol levels in follicular fluid on day 18. Expression of ANGPT-1 and -2 genes in CC did not differ among genetic groups neither among days of the estrous cycle, but TEK gene expression was higher in L1 than L2 gilts on day 18. Expression of VEGFA, VEGFR-2 and MMP-2 genes in CL did not differ among genetic groups and days of cycle, but VEGFR-1 expression was higher in Piau than L2 gilts on days 10 and 14, and it was higher in L1 than L2 gilts on day 14. The ANGPT-1/-2 and TEK genes expression in CL were significantly higher in Piau than L1 gilts on day 10. The ANGPT-2/ANGPT-1 gene expression ratio in CL was higher in L1 than Piau and L2 gilts at 14 days, suggesting a shorter luteal phase for L1 gilts. Results indicated differences among genetic groups for the pattern of the angiogenesis-related genes expression in CL along estrous cycles, which may be reflected in phenotypic traits such as ovulation rate, estradiol levels in follicular fluid and number and diameter of antral follicles.