The Influence of Moenomycin in the Diets of Broilers and Leghorn and Broiler Breeder Hens1

ABSTRACT Four experiments were conducted to study the influence of a new antibiotic, moenomycin, upon the performance of broilers, and broiler breeder, White Leghorn, and Brown Leghorn hens. With broilers maintained in floor pens, a significant body weight response at both four and eight weeks of age resulted from the feeding of moenomycin; however, there were no significant differences between the various levels of supplementation (0, 0.5, 1.0, 2.0 or 4.0 mg./kg.). Oxytetracycline supplementation of the basal diet gave a numerical but not significant im-provement in body weights. Broiler breeder hens received either 4 mg./kg. of moenomycin or 11 mg./kg. of oxytetra-cycline for four 28-day experimental periods. No significant treatment differences were found in egg production, feed efficiency, daily feed intake, body weight gains, mortality, egg weight or hatch of fertile eggs. However, a numerical improvement of egg production and hatch of fertile eggs, along with a slight decrease in average egg weight, did appear to result from moenomycin supplementation. Percent fertility was significantly reduced for groups receiving either moeno-mycin or oxytetracycline supplementation. White Leghorn hens maintained in floor pens received either a control diet or diets contain-ing 1 or 4 mg./kg- of moenomycin, or 4.4 mg./kg. of penicillin for a ten-month period. Brown Leghorn hens received identical treatments for an eight-month experimental period. Egg pro-duction, feed efficiency, daily feed intake, mortality, body weights and egg weights of either variety were not significantly influenced by treatment; however, a numerical egg production response occurred in the Brown Leghorns with either moenomycin or penicillin supplementa-tion