Resposta endometrial e luteal no balanço energético negativo induzido durante o reconhecimento materno da gestação em ovinos

Abstract

Negative energy balance (NEB) is one of the main causes of reduced fertility in ruminants. Our study hypothesis is that induced NEB influences maternal-embryonic communication, negatively impacting maternal recognition of pregnancy. For this reason, the aim of our study was to evaluate the effects of induced-NEB, in the first or second week of embryonic development, on maternal recognition of pregnancy and oxidative stress in the endometria and corpora lutea on Day 17 pregnant ewes. For this, 21 sheep were placed into four groups: control group, non-bred and non-pregnant (n=3); control group of pregnant women (n=6); NEB during the first week of embryonic development (FW; n=6); and NEB in the second week (SW; n=6). Our results demonstrate a moderate decrease in the expression of MX2 in the CL in the fasting group in the first week and an increase in the expression of MX1 in FW and SW in the endometrium and increased progesterone concentration in ewes submitted to fasting in the second week. Possibly, fasting was effective in causing hyperketonemia, but it was not enough to cause significant changes in the endometria and corpora lutea. Pregnant ewes under induced NEB showed the same pattern of oxidative stress gene expression and IFNs when compared with P control sheep. In conclusion, our study expresses a subclinical effect, normally animals that suffer NEB have higher BHB levels than those demonstrated here. Although NEB is inevitable in certain phases of the production system, minimizing it will result in minimal loss.