EFFICACY OF GAMMA-IRRADIATION IN PREVENTING MOLDINESS AND PRESERVING THE NUTRITIONAL-VALUE OF CORN GRAIN FOR BROILER CHICKS

The effect of gamma irradiation of whole-corn grains on mold development during storage and on nutritional value for broiler chicks was determined in two experiments. Moisture content (MC) of the grains was either ca. 13.5 (natural) or ca. 16% (moistened); irradiation was applied at dosages of 7 and 10 kilogray (kGy) with follow-up of fungal development during the next 80 and 96 days. Feeding tests were initiated after 120 and 173 days of storage in Experiments 1 and 2, respectively. Mold development was observed already after 11 days in moistened grains. Irradiation, particularly of grains with low MC, delayed, but did not prevent fungal development. Fat content of moistened grains at the end of the storage period was not changed in Experiment 1, but it decreased markedly in Experiment 2. Irradiation did not affect this variable. The moistened corn did not adversely affect chick performance in Experiment 1, whereas in Experiment 2 it significantly (P < .05) increased feed intake and weight gain and depressed feed efficiency. Irradiation did not affect either of the variables of chick performance. It was concluded that gamma irradiation at the dosages applied was effective in preventing moldiness of low MC corn grains for ca. 60 days. However, moldiness per se did not necessarily disqualify the grains for use in poultry nutrition. Before use, such grains should be analyzed for the presence of mycotoxins, and their fat content determined to ensure their safety and economical value.