FACTORS AFFECTING RYE (SECALE CEREALE L.) UTILIZATION IN GROWING CHICKS. I. THE INFLUENCE OF RYE LEVEL, ERGOT AND PENICILLIN SUPPLEMENTATION

Five experiments were conducted to evaluate the influence of rye level, ergot and penicillin on the utilization of rye by growing chicks. The effects of the following factors and/or treatments, respectively, were studied: increasing levels of rye replacing wheat in the diets for starting and finishing broiler chicks; ergot, pelleting and penicillin supplementation of rye diets; the cleaning of the beaks or vents of rye-fed chicks; and increasing levels of penicillin in rye diets containing different levels and types of protein supplements for Leghorn chicks. The results indicate that a diet containing 15% rye depressed the appetite and growth of young broiler chicks. Levels of rye higher than 15% in the diet depressed not only growth but also the efficiency of feed utilization in all chicks. The level of ergot in excess of three times that present in the uncleaned rye diet (0.11%) had no influence on chick performance. Wet excreta were produced by rye-fed but not by wheat-fed chicks. There was no relationship, however, between chick performance, and excreta "wetness," beak impaction and vent blockage. An improvement in chick performance was elicited by pelleting or penicillin supplementation of rye diets; the magnitude of the chick response to the latter treatment appeared to be influenced by the type and level of the dietary protein supplement. A dose-response study demonstrated that the maximum effective response to penicillin supplementation occurred when a rye–meat meal diet contained penicillin at or in excess of 160 mg/kg of diet; the corresponding maximum improvements in weight gain and the efficiency of feed utilization were 46 and 18%, respectively.