Plasma Thyroid Hormone Concentrations and pH Values of Some GI-Tract Segments of Broilers Fed on Different Dietary Citric Acid and Microbial Phytase Levels
Rouhollah Nourmohammadi, Seyed Mohammad Hosseini, Hamed Saraee and Alireza Arab
DOI : 10.3844/ajavsp.2011.1.6
American Journal of Animal and Veterinary Sciences
Volume 6, Issue 1
Problem statement: An experiment was conducted to study the effect of microbial phytase supplementation and citric acid on thyroid activity, relative weight of lymphoid organs and pH values of some GI-tract segments in broiler chickens fed corn-soybean meal based diets. Approach: The data was analyzed using a Randomized Complete Block Design (RCBD) with factorial arrangement of 3×3, three levels of citric acids (0, 3 and 6%) and three levels of phytase (0, 500 and 1000 IU kg−1). There were three replicates (with ten chicks in each replicate) for each treatment. A total of 270 Ross 308 broiler chicks were used. Results: Addition of citric acid to diets caused significant decrease in pH values of crop, gizzard, duodenum, jejunum and ileum (p<0.05) and caused significant increase (p<0.01) in plasma triiodothyronine (T3) concentration, T3:T4 ratio and relative weight of bursa and thymus, but had no significant effect on thyroxin (T4) concentrations. Microbial phytase significantly increased relative weight of thymus (p<0.01), but had no significant effects on thyroid gland activity, relative weight of bursa and values of pH in different parts of the GI-tract. Conclusion: Broiler chicks fed on acidifiers diets had better immune response resistance that lead to immunological advances. Also, decreasing pH in GI-tract by CA caused a beneficial effect in the inhibition of intestinal bacteria competition.
© 2011 Rouhollah Nourmohammadi, Seyed Mohammad Hosseini, Hamed Saraee and Alireza Arab. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.