Effect of dietary copper and age on tissue mineral composition of broiler-type chicks as a bioassay of inorganic copper sources
1989
Ledoux, D.R. | Henry, P.R. | Ammerman, C.B. | Miles, R.D.
An expriment was conducted with 192 day-old male Cobb feather-sexed chicks to study the relationship between high dietary concentrations of Cu and tissue Cu accumulation and to assess the influence of age on this relationship. Chicks were allotted randomly to a 4 x 3 factorial arrangement of treatments which included a corn-soybean meal basal diet (15.2 mg/kg Cu, DM) supplemented with 0, 100, 200 or 300 mg/kg Cu as reagent grade cupric acetate [Cu(C2H302)2.H2O] and fed for 1, 2 or 3 weeks. An age x Cu interaction (P less than .001) was observed for feed intake and gain. Liver Cu concentrations were not affected (P greater than .10) by dietary Cu at week 1, but increased (P less than .001) with increasing dietary Cu at weeks 2 and 3. Regression of log transformed liver Cu on dietary Cu by age indicated that this increase was quadratic (P less than .001) in nature. Copper concentrations in tissue other than liver were not affected (P greater than .10) by dietary Cu. However, dietary Cu affected several other tissue mineral concentrations. With the exception of muscle in which all minerals decreased (P less than .001) with age, tissue mineral response to age varied with tissue and mineral within tissue. Data indicated that liver Cu accumulation may be a useful bioassay criterion for determining bioavailability of inorganic Cu and that 2 weeks is the minimum time required for such an assay in chicks.
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