Fetal programming in sheep: effects on pre- and postnatal development in lambs

Abstract

This systematic review and meta-analysis aim to summarize the effects of maternal under or overnutrition during pregnancy on fetal weight and morphometric measurements during pregnancy, at birth and postnatal period in sheep. After completing the search, selection and data extraction steps, the measure of effect was generated by the individual comparison of each indicator with the average of the control and treated group (undernutrition or overnutrition) using the DerSimonian and Laird method for random effects. Subgroup analyses were also performed for lambing order, litter size, sex, as well as level, timing and duration of the intervention. Fetal weight during the first third of pregnancy was not affected by maternal under or overnutrition. On the other hand, undernutrition in the second and last third of gestation reduces the weight of the lamb both during pregnancy, at birth and during the postnatal period, requiring at least 120 postnatal days to achieve the same weight as its contemporaries in the control treatment. However, this reduction in weight is not accompanied by reductions in morphometric measurements, demonstrating that the animals were lighter, but of equal size. In overnutrition, there is an increase in fetal weight in the second third of gestation. However, in the last third of the gestational period, there are no differences in fetal weight for the multiparous subgroup, but it was reduced in primiparous ewes. There are no effects of overnutrition on birth weight, however, this result is highly heterogeneous. Thus, maternal nutrition of ewe during pregnancy has effects on fetal and postnatal weight, but not on size. Furthermore, the effects of undernutrition are more homogeneous while overnutrition showed heterogeneous responses

The Impact of Fetal Programming in Ewe Nutrition with Chromium Propionate or Calcium Salts of Palm Oil on the Meat Quality and Bone of the Progeny

“…Ewes in gestation and lactating have an increased nutritional requirement due to fetal growth, colostrum, and milk synthesis (NRC, 2007) and poor nutrition can result in metabolic diseases such as pregnancy toxemia [2]. However, maternal nutrition may affect lamb's body weight [3], development of the liver, lung, and pancreas [4], meat quality, and weight of premium cuts [5], and changes in bone tissue [6]. The fetal programming study is investigating the effect of maternal nutrition on offspring.…”

Maternal nutrient restriction in late pregnancy programs postnatal metabolism and pituitary development in beef heifers

“…This phenomenon has been observed in livestock species in response to maternal nutrient restriction during pregnancy with effects on fetal growth as well as skeletal muscle and pancreas function [ 5 – 8 ]. Additionally, maternal nutrient restriction during gestation has been shown to decrease postnatal growth rates in sheep progeny [ 9 – 11 ], pig progeny [ 12 ], and cattle progeny [ 13 , 14 ]. Furthermore, a number of cattle studies have reported reductions in economically important carcass traits such as hot carcass weight (HCW), yield grade, quality grade, and meat tenderness in response to maternal undernutrition [ 14 – 16 ].…”

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“…Consequences on bone development and mineralization caused by maternal nutrition are less common to be observed (SARTORI et al, 2020).…”

“…However, the formation of the placenta occurs earlier and maternal malnutrition can lead to a failure in placental development, consequently preventing the full growth potential of the fetus at the end of pregnancy (GREENWOOD; BELL, 2019b). Sartori et al (2020) published a review identifying studies with maternal under and overnutrition during pregnancy and its consequences on weight morphometric measurements of the progeny. This meta-analysis showed that effects of overnutrition are heterogeneous but those of undernutrition are consistent and influenced by litter size, time and duration of the intervention and overall reducing nutrient intake during pregnancy, mainly in the last third or during more than 90 days, produces lighter lambs, but does not influence their size.…”

“…At five days old, fetal organs were collected. Neck thymus, ovaries and peri-renal fat were heavier for the high energy treatment and liver mass were heavier for low energy lambs.Posnatal performanceMistakes in the nutritional management of pregnant ewes can lead to a deficient uteroplacental blood flow and supply of nutrients compromising fetal development BELL, 2003BELL, , 2019bREDMER;WALLACE; REYNOLDS, 2004;CASTRO-RODRÍGUEZ et al, 2020;SARTORI et al, 2020), consequently decreasing the efficiency in lamb production(SARTORI et al, 2020). The main factor that influences fetal growth and postnatal performance is maternal nutrition(CATON;HESS, 2010;NIELSEN, 2017).…”