Proceedings of The Physiological Society
University of Cambridge (2008) Proc Physiol Soc 11, C30
Prenatal diet and adult-onset obesity influence plasma amino acids in adult sheep
P. Rhodes1, C. Gray1, S. Rhind2, D. S. Gardner1
1. School of Veterinary Medicine and Science, University of Nottingham, Loughborough, United Kingdom. 2. Macauley Research Institute, Aberdeen, United Kingdom.
Introduction: Many studies have shown associations between a poor prenatal environment, often leading to low birth weight, and later physiological dysfunction. No study has examined a relationship between prenatal protein nutrition, whole body composition and amino acid status before and after a period of significant weight gain; the aim of the current study. Methods: 20 sheep were either fed a control protein diet (18% crude protein content) from day 0 (mating date) to term (~145days gestation; Control [CP], n=7) or a low protein (9% crude protein content) diet during early (0-65 days [LPE], n=7) or late gestation (65-145 days [LPL], n=6). At 18 months sheep were blood sampled (5ml, EDTA) and body composition determined by dual-energy X-ray absorptiometry (DXA). Subsequently, for 5 months, sheep were reared in an ‘obesogenic environment’ to gain weight. Blood sampling and DXA was then repeated. Plasma amino acid concentration (nmol/ml) was determined by GC-MS (EZ:faast, Phenomenex Ltd, CA, USA). Data are presented as estimated marginal means ± S.E.M. and were analysed by Repeated Measures General Linear Model and P<0.05 accepted as statistically significant (SPSS v14). Results: Birth weight was significantly lower in LPL vs. CP and LPE (4.37±0.19 vs. 5.25±0.19 and 5.12±0.20 kg) but weights at 18months were similar (CP, 57.2±2.1; LPE, 57.4±2.0; LPL, 54.6±2.1 kg). Body composition per se was unaffected by prenatal diet, but an obesogenic environment resulted in significant weight gain (from ~15% to ~30% fat). LPL animals gained significantly less fat than CP or LPE (7.1±0.9 vs. 10.9±0.9 and 10.6±0.9 kg). Overall, plasma amino acids decreased with obesity (lean, 8934±962 vs. obese, 6242±742 µM/ml). Principal components analysis indicated 7 amino acids to account for 95% variation with obesity; glycine, alanine, valine and glutamate all decreased whereas serine, aspartate and glutamine all increased. A representative canonical variate plot (mean, 95% CI) is shown in Fig 1. Discussion: Prenatal protein restriction during late, but not early, gestation reduced birth weight but had little effect on postnatal growth rate or body composition of adult sheep per se. When coupled with an obesogenic environment, low birth weight reduced the quantity of fat deposited. Resting amino acid metabolism appeared altered by prenatal diet and, when coupled with adult-onset obesity, significantly influenced individual amino acid status.
Where applicable, experiments conform with Society ethical requirements