DIETARY CHROMIUM SUPPLEMENTATION WITH OR WITHOUT SOMATOTROPIN TREATMENT ALTERS SERUM HORMONES AND METABOLITES IN GROWING PIGS WITHOUT AFFECTING GROWTH-PERFORMANCE

Twenty-four castrated male pigs were used in a 2 x 2 treatment array to determine the main effects of and interactions between dietary chromium supplementation and pituitary porcine somatotropin (ppST) administration on growth performance and serum hormone and metabolite concentrations. The treatments were 1) control (basal diet); 2) chromium (basal diet + 300 mug/kg diet added trivalent chromium as chromium picolinate); 3) ppST (100 mug/(kg body wt.d); and 4) chromium + ppST. Treatments were administered when pigs weighed between 30 and 60 kg. Blood was collected when pigs weighed 45 and 60 kg. All pigs treated with ppST exhibited improvements in growth performance (P < 0.05). Pigs given chromium showed no improvements in growth rate, feed efficiency or composition of gain. Measurements at 60 kg body weight revealed that ppST increased the cholesterol:HDL cholesterol ratio (P < 0.05). Chromium lowered serum insulin and glucose concentrations relative to controls (P < 0.05) and normalized the increase in glucose and insulin resulting from ppST treatment. No ppST x chromium interactions were noted, suggesting these changes in glucose and insulin metabolism are exerted through different mechanisms. These results indicate that chromium does not affect growth performance of young growing pigs. Chromium does normalize altered hormone and metabolite concentrations resulting from ppST treatment.