Chick Growth Response to Fish By-Products and Arsanilic Acid

FOLLOWING the reports of Morehouse (1949) and Bird et al. (1949), many others have confirmed that arsonic acids have a growth stimulating effect on chicks. Those reports have been excellently reviewed by Frost et al. (1955). Results with arsanilic acid (p-amino-phenylarsonic acid) indicate that its optimal dietary level is approximately 90 grams per ton of feed. According to Frost et al. (1955), chicks can tolerate up to ten times this level based on mortality, but growth inhibition can be expected at about the seven-fold level, or 630 grams per ton of feed. Most investigators have found that the mode of action of arsonic acids in promoting growth is similar to that of antibiotics, but only insofar as both influence microorganism populations in the intestine. The kinds of microorganisms that are affected is still questionable. Coates et al. (1955) found that both arsanilic acid and penicillin lowered intestinal weights of chicks …