QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by McCann, J. P. Articles by Beermann, D. H. Search for Related Content PubMed PubMed Citation Articles by McCann, J. P. Articles by Beermann, D. H.

Dynamic and Static Phases of Severe Dietary Obesity in Sheep: Food Intakes, Endocrinology and Carcass and Organ Chemical Composition¹

Department of Physiology, New York State College of Veterinary Medicine ^* Department of Animal Science, Cornell University, Ithaca, NY 14853

The chronology of changes in body weights, food intakes and plasma concentrations of selected metabolic hormones and metabolites were determined in sheep during the induction (dynamic) and static phases of diet-induced obesity. Lean adult Dorset ewes weighing 47 kg were fed a pelleted hay-grain diet at maintenance (lean; n = 7) or were fed the same diet ad libitum to a maximum intake of 3 kg·sheep^-1·d^-1 (obese; n = 8) for 78 wk. Body weight of obese sheep doubled (97 vs. 47 kg) by wk 42 of ad libitum intake. Average daily intakes of dry matter (12.8 g/kg) and digestible energy (165 kJ/kg) were comparable in maintenance-fed lean sheep and ad libitum-fed obese sheep consuming maintenance after wk 50, which began the static phase of obesity. Fasting plasma concentrations of insulin in the obese sheep increased steadily from 50 ± 6 pmol/L at wk 0 to a sustained plateau of 249 ± 21 pmol/L after wk 30. Plasma levels of glucose, immunoreactive glucagon and thyroid hormones were consistently greater (P < 0.05) in obese sheep than in lean sheep after wk 2, 3 and 25, respectively, of the experiment. Concentration of lipid (49 vs. 25%) in the carcass stripped of internal fat was greater (P < 0.01) in obese sheep than in lean sheep, but concentration of protein (10.4 vs. 15.3%) was less in the heavier carcass (58 vs. 24 kg) of the obese sheep. We conclude that hyperinsulinemia and abnormal fuel metabolism are early events during dynamic obesity and these defects persist throughout the static phase of obesity. Maintenance energy requirements relative to unit body weight (W^1.0) seem similar in lean and dietary obese sheep.

KEY WORDS: • dietary obesity • insulin • thyroid hormones • food intake • sheep

¹ Supported by National Institutes of Health Grant AM-05976.

² To whom correspondence and reprint requests should be addressed, at the current address: Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078-0353.

Manuscript received 4 September 1990. Revision accepted 28 August 1991.

This article has been cited by other articles:

				C. Anukulkitch, A. Rao, F. R. Dunshea, D. Blache, G. A. Lincoln, and I. J. Clarke Influence of photoperiod and gonadal status on food intake, adiposity, and gene expression of hypothalamic appetite regulators in a seasonal mammal Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R242 - R252. [Abstract] [Full Text] [PDF]