Effects of birth weight and dietary fat on intake, body composition, and plasma thyroxine in neonatal lambs

Abstract Intrauterine growth restriction (IUGR) is often observed in one of the fetuses carried by well-fed prolific ewes. This condition is the result of an insufficient placental size to cover the nutritional needs of the fetus during the near exponential growth phase of the last trimester. After birth, these IUGR offspring have an elevated appetite and lower maintenance energy requirements, suggesting dysregulation of homeostatic systems governing energy metabolism. It is also unknown whether the consequent increase in fatness occurs similarly in both visceral and carcass fractions. To address these questions, lambs differing in birth size (BS, IUGR vs. Normal, 2.6 ± 0.05 vs. 4.2 ± 0.07 kg, P < 0.001) were offered unlimited amounts of a low fat [LF; 22% of dry matter (DM)] or a high fat (HF; 38% of DM) milk replacer and slaughtered on day 14 of postnatal age (n = 7 to 8 for each BS × Diet); a second group of IUGR lambs (n = 3 for each diet) was slaughtered when they reached 8.5 kg, corresponding to the weight of Normal lambs on day 14. When normalized to body weight (BW), the DM and energy intake of IUGR lambs were higher than those of Normal lambs over the first 14 d of life (BS, P < 0.01), but contrary to expectations, the HF diet did not exacerbate these effects of the IUGR condition. Intrauterine growth restricted lambs had increased viscera fat with both diets (BS and Diet, P < 0.05) but increased carcass fat only with the LF diet (BS × Diet, P = 0.08); the fatness promoting effect of the IUGR condition was increased in both body fractions when lamb groups were compared at the fixed BW of 8.5 kg. A subset of metabolic hormones was analyzed, including the metabolic rate-setting hormone thyroxine (T4) and its possible positive regulator leptin. Plasma T4 was lower in IUGR than in Normal lambs at birth (P < 0.05) but then disappeared by day 7 of postnatal life (BS × Day, P < 0.01). On the other hand, the HF diet had no effect on plasma T4 over the first 3 d but caused an increase, irrespective of BS by day 11 (Diet × Day, P < 0.001). Plasma leptin increased with dietary fat and time (P < 0.06) but bore no relation to the effects of BS or Diet on plasma T4. These data show that IUGR and Normal lambs are similarly unable to adjust caloric intake in early life and that the fatness promoting effects of the IUGR condition are more pronounced in the viscera than in the carcass. These data also reveal dynamic regulation of plasma T4 by BS and Diet in neonatal lambs.

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Low plasma leptin in response to dietary fat in diabetes- and obesity-prone mice

Diabetes ◽

10.2337/diabetes.46.9.1516 ◽

1997 ◽

Vol 46 (9) ◽

pp. 1516-1520 ◽

Cited By ~ 20

Author(s):

R. S. Surwit ◽

A. E. Petro ◽

P. Parekh ◽

S. Collins

Keyword(s):

Dietary Fat ◽

Plasma Leptin ◽

Diabetes And Obesity

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Dietary fat type and energy restriction interactively influence plasma leptin concentration in rats

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)32195-7 ◽

1998 ◽

Vol 39 (8) ◽

pp. 1655-1660 ◽

Cited By ~ 5

Author(s):

Ming C. Cha ◽

Peter J.H. Jones

Keyword(s):

Dietary Fat ◽

Energy Restriction ◽

Plasma Leptin

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Regulation of plasma leptin in mice: influence of age, high-fat diet, and fasting

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1997.273.1.r113 ◽

1997 ◽

Vol 273 (1) ◽

pp. R113-R120 ◽

Cited By ~ 43

Author(s):

B. Ahren ◽

S. Mansson ◽

R. L. Gingerich ◽

P. J. Havel

Keyword(s):

Body Weight ◽

Dietary Fat ◽

High Fat Diet ◽

Plasma Insulin ◽

Plasma Concentrations ◽

Age Groups ◽

Fat Content ◽

High Fat ◽

Background Strain ◽

Plasma Leptin

Mechanisms regulating circulating leptin are incompletely understood. We developed a radioimmunoassay for mouse leptin to examine the influence of age, dietary fat content, and fasting on plasma concentrations of leptin in the background strain for the ob/ob mouse, the C57BL/6J mouse. Plasma leptin increased with age [5.3 +/- 0.6 ng/ml at 2 mo (n = 23) vs. 14.2 +/- 1.6 ng/ml at 11 mo (n = 15), P < 0.001]. Across all age groups (2-11 mo, n = 160), log plasma leptin correlated with body weight (r = 0.68, P < 0.0001), plasma insulin (r = 0.38, P < 0.001), and amount of intra-abdominal fat (r = 0.90, P < 0.001), as revealed by magnetic resonance imaging. Plasma leptin was increased by a high-fat diet (58% fat for 10 mo) and reduced by fasting for 48 h. The reduction of plasma leptin was correlated with the reduction of plasma insulin (r = 0.43, P = 0.012) but not with the initial body weight or the change in body weight. Moreover, the reduction in plasma leptin by fasting was impaired by high-fat diet. Thus plasma leptin in C57BL/6J mice 1) increases with age or a high-fat diet; 2) correlates with body weight, fat content, and plasma insulin; and 3) is reduced during fasting by an action inhibited by high-fat diet and related to changes of plasma insulin.

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Effects of the lipase inhibitor orlistat on intake and preference for dietary fat in rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1996.271.1.r48 ◽

1996 ◽

Vol 271 (1) ◽

pp. R48-R54 ◽

Cited By ~ 2

Author(s):

K. Ackroff ◽

A. Sclafani

Keyword(s):

Body Weight ◽

Dietary Fat ◽

Body Weight Gain ◽

Caloric Intake ◽

Female Rats ◽

Control Group ◽

Fat Intake ◽

Fat Absorption ◽

Drug Induced ◽

Dietary Fat Intake

Orlistat (Ols), a potent inhibitor of pancreatic lipase, was added to the fat source (1 or 4 mg Ols/g fat) of a macronutrient self-selection diet fed to adult female rats. The rats responded to the drug-induced reduction in fat absorption by decreasing their dietary fat intake and increasing their protein and carbohydrate intake in a dose-related manner. Total caloric intake also increased, but body weight gain was inhibited compared with the nondrug control group. When Ols was removed from the diet, nutrient selection, caloric intake, and body weight returned to control levels. In additional short-term experiments (30 min/day), rats developed a preference for a plain fat diet over an Ols-fat diet (4 mg/g fat) and also for a cue flavor paired with plain fat over a flavor paired with Ols-fat. Yet, when not given the choice, the rats consumed nearly as much Ols-fat as plain fat diet. These results indicate that, by reducing fat absorption, Ols reduced the attractiveness of dietary fat, although it did not make the fat diet aversive. In clinical use, lipase inhibitors may be effective in reducing dietary fat intake by reducing both the consumption and absorption of fat.

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A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations

American Journal of Clinical Nutrition ◽

10.1093/ajcn.82.1.41 ◽

2005 ◽

Vol 82 (1) ◽

pp. 41-48 ◽

Cited By ~ 19

Author(s):

David S Weigle ◽

Patricia A Breen ◽

Colleen C Matthys ◽

Holly S Callahan ◽

Kaatje E Meeuws ◽

...

Keyword(s):

Body Weight ◽

Caloric Intake ◽

High Protein Diet ◽

High Protein ◽

Protein Diet ◽

Ad Libitum ◽

Plasma Leptin

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Catecholamines Mediate Multiple Fetal Adaptations during Placental Insufficiency That Contribute to Intrauterine Growth Restriction: Lessons from Hyperthermic Sheep

Journal of Pregnancy ◽

10.1155/2011/740408 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 28

Author(s):

D. T. Yates ◽

A. S. Green ◽

S. W. Limesand

Keyword(s):

Intrauterine Growth Restriction ◽

Somatic Growth ◽

Placental Insufficiency ◽

Growth Restriction ◽

Postnatal Life ◽

Adaptive Responses ◽

Hepatic Gluconeogenesis ◽

Intrauterine Growth ◽

Metabolic Adaptations ◽

Insulin Dependent

Placental insufficiency (PI) prevents adequate delivery of nutrients to the developing fetus and creates a chronic state of hypoxemia and hypoglycemia. In response, the malnourished fetus develops a series of stress hormone-mediated metabolic adaptations to preserve glucose for vital tissues at the expense of somatic growth. Catecholamines suppress insulin secretion to promote glucose sparing for insulin-independent tissues (brain, nerves) over insulin-dependent tissues (skeletal muscle, liver, and adipose). Likewise, premature induction of hepatic gluconeogenesis helps maintain fetal glucose and appears to be stimulated by both norepinephrine and glucagon. Reduced glucose oxidation rate in PI fetuses creates a surplus of glycolysis-derived lactate that serves as substrate for hepatic gluconeogenesis. These adrenergically influenced adaptive responses promotein uterosurvival but also cause asymmetric intrauterine growth restriction and small-for-gestational-age infants that are at greater risk for serious metabolic disorders throughout postnatal life, including obesity and type II diabetes.

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Relationship of plasma leptin to plasma insulin and adiposity in normal weight and overweight women: effects of dietary fat content and sustained weight loss

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.81.12.4406 ◽

1996 ◽

Vol 81 (12) ◽

pp. 4406-4413 ◽

Cited By ~ 86

Author(s):

P. J. Havel

Keyword(s):

Weight Loss ◽

Dietary Fat ◽

Plasma Insulin ◽

Fat Content ◽

Normal Weight ◽

Overweight Women ◽

Sustained Weight Loss ◽

Plasma Leptin ◽

Relationship Of

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Ontogeny of diet-induced obesity in selectively bred Sprague-Dawley rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00235.2003 ◽

2003 ◽

Vol 285 (3) ◽

pp. R610-R618 ◽

Cited By ~ 67

Author(s):

Matthew R. Ricci ◽

Barry E. Levin

Keyword(s):

Leptin Receptor ◽

Splice Variants ◽

Caloric Intake ◽

High Energy ◽

Sprague Dawley ◽

Low Fat Diet ◽

Diet Induced Obesity ◽

Leptin Sensitivity ◽

Sprague Dawley Rats ◽

Plasma Leptin

Outbred Sprague-Dawley rats selectively bred for their propensity to develop diet-induced obesity (DIO) become heavier on low-fat diet than those bred to be diet resistant (DR) beginning at ∼5 wk of age. Here we assessed the development of metabolic and neural functions for insights into the origins of their greater weight gain. From week 5 to week 10, chow-fed DIO rats gained 15% more body weight and ate ∼14% more calories but had only slightly greater adiposity and plasma leptin than DR rats. From day 3 through week 10, DIO and DR rats had similar mRNA expression of arcuate nucleus neuropeptide Y, proopiomelanocortin, agouti-related peptide, and all splice variants of the leptin receptor (OB-R). When fed a high-energy (HE; 31% fat) diet, 7-wk-old DIO rats had a 240% increase in plasma leptin levels after only 3 days. Despite this early leptin rise, they maintained a persistent hyperphagia and became more obese than chow-fed DIO rats and DR rats fed chow or HE diet. Their failure to reduce caloric intake, despite high levels of leptin, suggests that selectively bred DIO rats might have reduced leptin sensitivity similar to that seen in the outbred DIO parent strain.

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