154 UNDERNUTRITION DURING THE PERICONCEPTIONAL PERIOD IN EWES AFFECTS THE BLOOD PRESSURE AND WEIGHT OF THEIR NEONATAL LAMBS

Abstract

Evidence from epidemiological and experimental studies has shown that maternal undernutrition during pregnancy can alter fetal growth and development and is associated with increased risk of hypertension and cardiovascular disease in the offspring. However, there is a paucity of data examining the effect of undernutrition during the periconceptual period on offspring health. Therefore, we investigated the impact of ewe undernutrition during the periconceptional period on lamb birth weight and blood pressure. Crossbred ewes (n = 166) were individually penned and randomly allocated to 1 of 2 treatments and fed either 0.7 (restricted) or 1.1 (control) maintenance energy requirements from 28 days prior until 7 days post-mating. After Day 7, ewes in both treatments were managed similarly until parturition. Following parturition, lamb gender, birth weight, and blood pressure were recorded. Lamb weight and blood pressure were subsequently measured at 4 and 10 weeks of age. Restricted ewes lost 2.6 ± 0.2 kg over the treatment period compared with control ewes which gained 1.7 ± 0.58 kg (P < 0.01). There was no treatment effect on lamb birth weight in either singleton or twin gestations. However, at 4 and 10 weeks of age singleton lambs born to nutritionally restricted ewes were heavier than those born to control ewes (males, n = 17: 19.4 ± 0.1 vs. 16.4 ± 0.1 kg; females, n = 16: 34.9 ± 1.0 vs. 30.9 ± 1.6 kg, P < 0.05). Blood pressure, measured within the first 24 h of life, was higher (P < 0.05) in singleton lambs born to nutritionally restricted mothers compared to controls (males: systolic 126 ± 11 vs. 94 ± 5; diastolic 99 ± 12 vs. 58 ± 5; mean 112 ± 11 vs. 77 ± 5 mmHg; P < 0.05; females: systolic 126 ± 11 vs. 94 ± 5; diastolic 99 ± 12 vs. 58 ± 5; mean 112 ± 11 vs. 77 ± 5 mmHg; P < 0.05). This difference was no longer apparent at 4 or 10 weeks of age. Mean blood pressures of twin lambs at birth and 4 weeks of age were numerically greater in the restricted than in the control treatment but were significantly different only among male twin groups at 4 weeks of age (diastolic 77 ± 4 vs. 94 ± 4; mean 96 ± 4 vs. 110 ± 3 mmHg; P < 0.01). Maternal undernutrition during the periconceptional period was associated with increased offspring weight at 4 and 10 weeks of age in singletons, as well as alterations in offspring cardiovascular function in both singletons and twins. These findings suggest that maternal nutrition at the time of conception influences offspring health. Exact mechanisms remain to be elucidated but may involve genetic modification.

This research was funded by IRCSET and University College Dublin.