Effect of protamine zinc insulin on feed intake and weight gain in broiler chicks

Ten-day old Robro broiler chicks were used to test the effect of daily subcutaneous injections of two insulin levels (5- and 10-IU . kg-1 BW) administered for two different periods (5 and 21 days). Birds which received either 5- or 19-IU insulin significantly increased their feed intake over those of the controls (P less than 0.05). However, the lower insulin dose was found to be more effective in increasing both the feed consumption and weight gain of the birds, especially if administered for a long period. Between the injection periods, the high insulin dose seemed to have a greater carry-over effect. On the other hand, the administration of 5- or 10-IU insulin for either 5 or 21 days had no effect on efficiency.