Effects of micronization, tempering, and flaking on the chemical characteristics of wheat and its feeding value for broiler chicks

Abstract

Five experiments were conducted to study the effects of micronizing, tempering and flaking of wheat (cv. Genesis) on the chemical characteristics and its feeding value for broiler chicks. Samples of wheat were micronized (infrared invisible band with wavelengths of 1.8 to 3.4 µ) at 90, 105, and 120°C for 50 s, with or without tempering to 20% moisture, and with or without flaking. Micronization at 120°C produced negative effects on weight gain and feed efficiency (0–18 d). Tempering reduced protein solubility in 0.2% KOH, increased the solubility of dietary fibre, and increased in vivo digesta viscosity and in vitro extract viscosity as well as diet AME. Flaking wheat had no effect on broiler performance in exps. 3 and 4, but decreased growth rate and feed efficiency in exp. 5 despite improved dietary AME. Flaking decreased protein solubility at 120°C but had little effect at lower temperatures. The lowest protein solubility was found in the sample that was tempered, micronized at 120°C, and then flaked. In conclusion, micronization at 90 and 105°C improved the feeding value of wheat for broiler chickens. Tempering and flaking may be beneficial at lower micronization temperatures, but can result in lower nutritional value at higher micronization temperature. Key words: Wheat, micronization, metabolizable energy, broiler