Chick Growth Response to Condensed Fish Solubles and Varying Levels of Terramycin

THE use of antibiotics to promote increased growth rates in poultry is well established. Coates et al. (1951, 1952) have shown that rearing of chicks in new quarters replaced the need for antibiotics in the diet. This finding was confirmed by Hill et al. (1953) and Lillie et al. (1953). Starting with new batteries in previously unused quarters, Hill and Kelly (1953) were unable to demonstrate a growth response in chicks from a low level of aureomycin in 3 successive trials but found that a high level significantly stimulated early growth. These authors (1954) later repeated their finding with penicillin and further showed that the growth response to a high level of the antibiotic did not occur on a vegetable-protein type diet in the absence of fish meal. Heretofore, the use of high levels of antibiotics has been accepted, chiefly, as therapeutic and preventative agents to combat chronic respiratory disease …