Purdue University Agricultural Experiment Station Lafayette, Indiana
EFFECTS OF HYGROMYCIN AND A COMBINATION OF ANTIBIOTICS ON GROWING-FINISHING SWINE* Department of Animal Husbandry J. H, Conrad and W. M. Beeson
Antibiotics have been studied continuously as growth stimulants for swine during the past eight years. Prior to Iihygromycin,t? most antibiotics have stimulated gains oy their effects on the ;,bugsa (intestinal microflora) of the pig or animal to which Lt was fed. However, the primary effects of the antibiotic hygromycin appear to be brought about by its unique ability to control certain internal swine parasites (round-worms, nodular worms and whip worms).
The results of a preliminary study comparing aureomycin, arsanilic acid and hygromycin have been previously reported by Purdue (A. H, Mimeo. 214). In this study, aureomycin increased gains 6.8$, arsanilic acid increased gains 8.1$, and hygromycin increased gains 8.8$. After the experiment was terminated, an average of 14.5 round-worms per pig were expelled by the control pigs, an average of 18.2 roundworms were expelled from the arsanilic acid-fed pigs and no roundworms were expelled by the pigs that had been fed hygromycin. Consequently, it was impossible to determine from this study if hygromycin stimulated gains because of its control on roundworms or because of its true antibiotic effect on possibly a combination of the two preceding effects.
In view of these preliminary findings and the results obtained by others, an experiment was conducted to determine:
(1) the effects of hygromycin when fed to wormed and unwormed pigs and
(2) the effects of hygromycin when fed in addition to a combination of growth stimulating antibiotics to both wormed and unwormed pigs.
Experimental Plan
Eight lots of 10 Duroc pigs each were used. Pigs seven to eight weeks of age nich averaged 32 pounds initially were used. The experimental treatments were as ollows:
UNWORMED
Lot 1 - Control
Lot 2 - Hygromycin B, 12 grams per ton (12 million units) 1/
The authors wish to acknowledge Dr, T, M, Means and associates of Eli Lilly and Co., for their assistance in obtaining the information on the helminth infestation. Also to Fred Vandergraff and associates for feeding and caring for the experimental animals. Aureomycin was furnished by American Cyanamid Co., Pearl River, New York; Zinc-Bacitracin-Penicillin by Commercial Solvents, Terre Haute, Ind.; Hygromycin by Eli Lilly and Co., Indianapolis, Ind.; and Terramycin by Chas. Pfizer and Co., Terre Haute, Ind.
1/ Hygromycin B was supplied from a commercially available product which assayed 2.75 grams of hygromycin B and 1,54 grams of hygromycin A per pound.
Mimeo A. Ha 233 May, 195S