Date of Award

1995

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Animal Science (Animal, Dairy, and Poultry Sciences)

First Advisor

L. Lee Southern

Abstract

Three experiments were conducted with pigs and four experiments were conducted with chickens to determine the effects of supplemental dietary Cr on growth performance, carcass characteristics, tissue minerals and plasma metabolite and hormone concentrations. In pigs (Exp. 1) 200 ppb Cr from seven different sources tended to decrease performance during the grower phase and increase growth performance during the finisher phase. Dietary Cr had minimal effects on plasma metabolite and hormone concentrations and Cr did not affect carcass characteristics. In general, dietary Cr increased tissue Cr concentration, except for longissimus muscle (LM). In Exp. 2, pigs were fed 400 ppb Cr as Cr chloride, Cr nicotinate, or Cr picolinate (CrPic) to determine the effect of these Cr sources on i.v. glucose tolerance and insulin sensitivity. None of the Cr sources affected glucose clearance rate or half-life, or insulin clearance rate or half-life. In Exp. 3, the interactive effects of two levels of dietary lysine, two levels of dietary Cr, and two levels of pen space were evaluated. During the finisher phase, Cr increased average daily gain and gain/feed of pigs fed 80% of the lysine requirement but not in pigs fed 120% of the lysine requirement. In addition, Cr decreased tenth rib fat thickness (TRF) in pigs given adequate pen space but increased TRF of pigs given inadequate pen space. Dietary Cr supplementation did not affect LM area. Three experiments were conducted to determine the effect of CrPic on growth performance, plasma metabolites and hormones, and carcass composition of broilers. In broilers fed CrPic for two weeks, Cr decreased percentage of dry matter of the carcass and tended to decrease percentage carcass fat. In broilers fed CrPic for four weeks, Cr supplementation increased ventriculus weight and increased carcass ash percentage. In broilers fed CrPic for seven weeks, Cr decreased abdominal fat pad weight. Dietary Cr had minimal effects on plasma metabolites and hormones in broilers. In a fourth experiment with broilers, CrPic did not affect glucose tolerance or insulin sensitivity. Under the conditions of these experiments dietary Cr did not affect body composition and metabolism of pigs and broilers.

Pages

155

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