Thyroid Activity, Some Blood Constituents, Organs Morphology and Performance of Broiler Chicks Fed Supplemental Organic Acids

Abstract

A total number of 189 one d-old Hubbard broiler chicks were randomly divided into seven treatment groups of three replicates, 9 chicks each. The first group was served as control and fed the basal diets. While, the other six groups were received the basal diet supplemented with acetic acid (AC), citric acid (CA) or lactic acid (LA) at different levels of 1.5 and 3.0 % of diet, respectively. The experiment was lasted when chicks were 42 d old. Thyroid gland activity, some blood components, organ morphology, pH level of some gastrointestinal tract (GI-tract) segments and performance were measured. The results showed that dietary acidification elevated significantly concentration of T3 as well as T3:T4 ratio, but T4 level was not significantly affected. Moreover, the effect was clearly notable with CA and AC. Chicks fed acidified diets had better immune response as indicated by their higher serum globulin and relative lymphoid organs than the control. Similarly, higher calcium and phosphorus concentrations were noted. On the other hand, significant reduction in abdominal fat and serum level of cholesterol and total lipid was achieved due to dietary acidification. The liver functions did not adversely alter, in response to addition of organic acidifiers. Addition of any level and source of organic acids increased feed digestion and absorption as a result of increasing relative pancreas weight and small intestine density (indication of the intestinal villi dimension). The pH values in different GI-tract segments were insignificantly decreased with supplemental all types and doses of AC, CA and LA. Broiler chicks of dietary organic acids had superior improvement in live body weight (LBW), body weight gain (BWG) and feed conversion ratio (FCR) as compared to those of unsupplemented diet. No remarkable differences were noted between the addition of 1.5 and 3% of either AC, CA or LA in most studied traits. Key words: Organic acids, broiler, thyroid hormones, serum, morphology, pH and performance