Effect of protein sources and restricted feeding on some blood parameters and performance of chickens

摘要

The aim of the study was to investigate the influence of the type of animal protein contained in diets and restricted feeding on the Thyroxin (T4) and Triiodothyronine (T3) level in chickens' blood serum. Leghorn bread chickens were fed with two kindsof mixture. In the test mixture, protein from fish meal was replaced with livex. During the last stage of the experiment some of the birds continued to receive the same mixture, but were also subjected to a skip-a-day regimen (the chickens were deprivedof feed one day and consumed feed on the alternate day). Material for the study was taken on the 49th day following 14 or 21 days of feed restriction. It was noted that a change of animal protein in the diet and, to a greater extent, food restriction, leads to reduced growth and body weight gain (p<0.01). No changes were observed in most of the determined hemato-logical parameters. A change in the heterophil-lymphoeyte ratio (H/L), characteristic for stress, was observed in birds fed with a diet containing livex. No clear changes in the T4 concentration were observed (p>0.05), but a decrease in T3 was noted (p<0.01) in birds with limited feed access. The results seem to illustrate the dynamics and intensity of adaptation appearing during the course ofstress. The noted level rates of T3 and T4 clearly indicate the dependence of their changes on the type of external factors and, above all, on the time of their influence.