Date of Completion
Fetal programming is defined as when a stimulus at a vital stage of development results in permanent effects that persist throughout the lifetime of the individual (Lucas, 1991). There is evidence that poor maternal diet, consisting of both undernutrition and overnutrition, during gestation has permanent negative effects on the growth and development of offspring through fetal programming. Fetal programming enhances the ability of the fetus to absorb and use nutrients while in-utero, ensuring postpartum survival (Hales and Barker, 1992). However, in a postnatal environment where nutrition is plentiful, fetal programming results in negative health consequences (Wu et al., 2006). We hypothesized that both lambs born to nutrient-restricted ewes (RES lambs), and lambs born to overfed ewes (OVER lambs) would grow smaller than lambs born to control ewes (CON lambs), and would have alterations in circulating hormones of the somatotropic axis, and leptin. We also hypothesized that there would be no effect of postnatal diet, whether lambs suckled from the ewe or were bottle-fed. Additionally, we hypothesized that ewes would maintain longterm effects of gestational diet. We did not find any difference, due to maternal diet, in suckling lamb body weight from birth to 9 months of age, with all lambs gaining on average 0.24 kg/day. There was also no difference in IGF-1, GH, or leptin concentration. OVER lambs had significantly more IGFBP-3 than CON lambs (P < 0.05) but there was no difference between RES and CON lambs, and there was no difference in IGFBP-2. In comparing postnatal diet, suckling ewes maintained heavier body weight (P < 0.01), as far as 3 months postpartum, as well as increased IGF-1 (P < 0.01), leptin (P < 0.01) and a tendency for increased IGFBP-3 (P < 0.1). There was no difference in GH (P = 0.70). Ewes maintained longterm effects of gestational diet. Although there was no difference in ewe body weight, OVER ewes maintained significantly more circulating IGF-1 than CON ewes (P < 0.05), and increased IGFBP-3 concentrations (P < 0.05). There was also no difference in IGFBP-2 concentration over time. RES ewes had significantly more circulating GH than CON ewes (P < 0.05). Lastly, CON ewes tended to have more circulating leptin (P < 0.1). Therefore, there are other confounding factors than just maternal gestational diet that affect postnatal lamb growth, including postnatal diet. Additionally, ewes maintain longterm effects of gestational diet that have the potential to affect all future offspring.
Fox, Amanda R., "The Effects of Maternal Diet During Gestation on Postnatal Growth of Lambs and on Metabolic Hormones in Lambs and Ewes" (2013). Honors Scholar Theses. 299.