Abstract
An experiment was conducted to examine the effect of pathogenic Escherichia coli inoculated into the yolk sac of day-old turkeys. Escherichia coli was isolated from the yolk sac of stunted poults and inoculated directly into the yolk sac of day-old birds. Poults were administered either .1 ml of uninoculated sterile Todd-Hewitt broth or .1 ml of a 10−3 or 10−2 dilution of a 24-hr E. coli culture containing 3.4 × 108 viable bacteria/ml. In addition, poults were fed either 28 or 22% protein diets from 0 to 21 days of age to form a 3 × 2 factorial arrangement. Body weight gain and feed consumption were measured weekly, and dry matter and protein retention and nitrogen-corrected metabolizable energy were measured from 7 to 10 and 17 to 20 days postinoculation. Intestinal mucosal dipeptidase and maltase activities were determined at 21 days of age.Average mortality by 7 days of age was increased from 1 to 36% from the E. coli inoculation of the yolk sac. Escherichia coli significantly depressed body weight gain and feed consumption 27 and 30, 13 and 16, and 6 and 8%, respectively, during the first, second, and third weeks of the experiment but failed to affect feed efficiency. Feeding a 28% protein diet alleviated the depression in feed consumption and body weight gain to some extent compared with a substantial depression at 22% protein.Nitrogen content and gross energy of the excreta were increased by both dilutions of E. coli for the 7 to 10-day period; this was indicative of a malabsorption of nutrients. Dry matter and nitrogen retention values were variable in the 7 to 10-day period and did not differ during the 17 to 20-day period. Changes in mucosal maltase and dipeptidase activities varied along the length of the intestine at 21 days of age.
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