The Level of Feed Intake Affects Embryo Survival and Gene Expression During Early Pregnancy in Gilts

Abstract

Appropriate feed intake level would enhance embryo survival. This study investigated the relationship among feed intake level, embryo survival, hormone secretion and mRNA expression. Fifty-four Landrace x Yorkshire crossbred gilts were allotted to three treatment groups of high (H, 2 x maintenance), medium (M, 1.2 x maintenance) and low (L, 0.6 x maintenance) after mating, to study the effect of feed intake levels on embryo survival, hormone secretion and mRNA expression of leptin, obesity receptor (ob-R), signal transducer and activator of transcription-3 (STAT3), DNA methyltransferase 1 (DNMT1), retinol-binding protein 4 (RBP4), fibroblast growth factor receptor 2 (FGFR2) and progesterone receptor (PGR) in embryos. Blood samples and embryos were collected for hormone concentrations determination and gene expression analysis. Slaughter weight, total weight gain and net weight gain were affected (p < 0.05) by dietary treatment. Embryonic survival was 80.23% and 78.45% in M group on days 25 and 35 of pregnancy, respectively, and was greater (p < 0.05) in M than H and L groups. Serum insulin-like growth factor-I and leptin concentrations enhanced (p < 0.05) with the increased feed intake, but progesterone concentrations were lower (p < 0.05) in H than M and L groups and no difference (p > 0.05) between M and L on days 25 and 35 of pregnancy. Real-Time PCR indicated that gene expression pattern of leptin, ob-R, STAT3 and DNMT1 were the highest (p < 0.05) in H group on days 25 and 35 of pregnancy. Transcript expression level of RBP4 and FGFR2 were the highest (p < 0.05) in M group on days 25 and 35 of pregnancy. Significantly higher (p < 0.05) expression of PGR was observed in L group on day 25 and in M group on day 35 of pregnancy. Our data suggest that 1.2 x maintenance feed intake level promoted the appropriate hormone secretion and enhanced genes expression in RBP4, FGFR2 and PGR, and thus resulted in better embryo survival compared with the high and low groups.

Leptin in farm animals: where are we and where can we go?

“…Cyclic activity resumed earlier in sows with higher leptin on day 5 PP (Summer et al, 2009) so that leptin may link metabolic status and fertility in sows also. Xu et al (2009) fed Landrace 3 Yorkshire gilts at 0.6, 1.2 or 2 M after mating and found more viable embryos and the highest 25-day embryo survival rate (80%) in gilts fed at 1.2 M. Plasma leptin levels reflected the feed intake. Leptin given to rabbit does for 1-week before inducing ovulation did not affect offspring number or weight but did increase the proportion of pregnant females and numbers of live offspring (Sirotkin et al, 2009).…”

Dietary energy intake affects fetal survival and development during early and middle pregnancy in Large White and Meishan gilts

“…Dietary energy intake levels play a major role in the regulation of swine reproductive performance ( Quesnel et al, 2010 , Hoving et al, 2011 ). An increased level of dietary energy intake after mating has been shown to reduce systemic progesterone concentrations ( Jindal et al, 1997 ), and thus affects endometrial secretory functions ( Lonergan et al, 2013 ) eventually leading to increased embryo mortality in early pregnancy ( Xu et al, 2010 ). Interestingly, energy intake seems to display a specific action within the Chinese Meishan (MS) pig to modulate reproductive performance.…”

The importance of optimal body condition to maximise reproductive health and perinatal outcomes in pigs

“…Malnutrition during early pregnancy was shown to compromise the expression of several genes important for adequate embryo-maternal interactions. Key developmental genes encoding for proteins such as retinol-binding protein 4 (RBP4), which is considered a candidate gene for litter size and uniformity (199) , and DNA (cytosine-5)-methyltransferase 1 (DNMT1), which has an important function in epigenetic regulation of gene expression (200) , were decreased in gilts that were feed-restricted during early pregnancy. Likewise, feed-restricted females during the peri-conceptional period showed lower expression of DNMT1 and DNMT3a mRNAs and their protein abundance in uterine tissues as well as having lower concentrations of oestradiol-17β in uterine flushing (201) .…”