THE NUTRITIVE VALUE OF NAKED OATS FOR BROILER CHICKS AS AFFECTED BY DIETARY ADDITIONS OF OAT GUM, ENZYME, ANTIBIOTIC, BILE SALT AND FAT-SOLUBLE VITAMINS

Abstract

Five experiments were conducted with broiler chicks to evaluate naked oat (NO) as a major dietary ingredient and to identify means of ameliorating its growth-depressing effects. Substituting naked oats at concentrations of 0–600 g kg⁻¹ for corn in a broiler starter diet gave a dose-dependent decrease in weight gain and feed efficiency. Incorporation of β-D-glucanase into a NO diet increased growth of chicks presumed by decreasing β-glucan viscosity whereas increasing the β-glucan content of the diet by addition of oat gum or oat brans decreased rate of growth and feed efficiency. Autoclaving NO or supplementing a 600 g kg⁻¹ NO diet with neomycin or penicillin increased weight gains, but feed efficiency effects were inconsistent. True metabolizable energy values for naked oats and oat bran as determined with chicks were 16.2 and 11.5 MJ g⁻¹ dry matter, respectively. True availabilities of energy, ether extract and amino acids were reduced by, respectively, 10, 5 and up to 8% by addition of oat gum to naked oats and, 2.4, 24 and up to 8% by ethanol deactivation of oat bran enzymes. Supplementation of a NO diet with antibiotic, bile salt and water-miscible, fat-soluble vitamins in factorial combination demonstrated that reduced absorption of lipids, including fat-soluble vitamins may decrease energy values and growth in chicks fed naked oats. The β-glucan content of naked oats appears to be the factor responsible for poor utilization of the feedstuff by chicks. The effect of this factor was overcome by treatment with enzyme or to a lesser degree by dietary supplementation with antibiotics, bile salt or fat-soluble vitamins. Key words: Oat (naked), β-glucan, enzyme, autoclaving, bile salt, fat-soluble vitamin phytase, chick