Objective: To study the changes in the viscera weight and intestinal density of broiler chickens in response to T3-induced ascites, caused by T3-supplementation of the diet.
Design: Experimental study.
Animals: One hundred and fifty, day old, male Ross broiler chicks.
Treatment: Triiodothyronine (T3).
Procedure: The chickens were randomly divided into two equal groups (Control and T3-treated). Diet of T3-treated group was supplemented with 1.5 ppm T3 for five weeks. At the end of each week five chicks from either group (ten chicks in total) were separated, and sacrificed. After exsanguinations and opening the thoracic and abdominal cavities ,the hearts and visceras were removed. The weight of right ventricle (RV) and total ventricles (TV s) of the heart were measured. The weight of viscera and weight and length of the intestines were also determined.
Statistical analysis: T -test.
Results: In T3-treated group, RV /TV s significantly increased at the end of the 3rd, 4th, and 5th week, but the viscera weight was significantly decreased at the same time. The intestinal lengths were significantly reduced at the end of the 2nd, 4th, and 5th week, in response to T3 supplementation of the diet, but the reduction of intestinal weight and density were significant at the end of the 3rd week.
Conclusion: According to the results of this study the increases in RV /TV s and the decreases in viscera weight and intestinal length seem to be related to T3-induced ascites. The reductions in intestinal weight and density seen at the end of 3rd week did not last for the following two weeks. This might indicates a transient reduction in thickness of the intestinal wall at the end of the 3rd week and a direct proliferative effect of T3 on the intestinal crypt cells during the 4th and 5th weeks. J.Fac. Vet.Med. Univ. Tehran. 59,4:395¬399,2004.