بررسي اثر منابع و سطوح يد جيره بر عملكرد، صفات لاشه، تلفات ناشي از سندرم افزايش فشار خون ريوي (آسيت)، هورمون هاي تيروئيدي و فراسنجه هاي بيوشيميايي خون جوجه هاي گوشتي تحت تنش سرمايي

Effects of Dietary Sources and Levels of Iodine on Performance, Carcass Traits, Mortality Due to Pulmonary Hypertension Syndrome (Ascites), Thyroid Hormones, and Serum Biochemical Parameters of Broiler Chickens under Cold Stress Condition

زمينه مطالعه با توجه به اهميت عنصر يد در ساخت هورمون هاي تيروييدي، سطوح مختلف يد در جيره مي تواند در بروز سندرم آسيت تاثير گذار باشد. هدف بررسي اثرات استفاده از منابع و سطوح مختلف يد بر عملكرد، صفات لاشه، تلفات آسيت، هورمون هاي تيروييدي و فراسنجه هاي بيوشيميايي خون جوجه هاي گوشتي تحت تنش سرمايي. روش كار مطالعه حاضر با استفاده از 375 قطعه جوجه يك روزه گوشتي نر در قالب طرح كاملا تصادفي با 5 تيمار، 5 تكرار و 15 پرنده در هر تكرار انجام گرفت. جهت القاي آسيت از 14 روزگي دماي سالن به 15 درجه سانتي گراد كاهش يافت و تا آخر دوره اين دما حفظ گرديد. تيمارهاي آزمايشي عبارت بودند از: تيمار شاهد (جيره پايه با مقدار يد در سطح توصيه 25/1 ميلي گرم در كيلوگرم)، جيره پايه + يديد پتاسيم (KI) با سطوح يد (25/6 و 75/3 ميلي گرم در كيلو گرم) و جيره پايه + يدات كلسيم [Ca(IO3)2.H2O] با سطوح يد (25/6 و 75/3 ميلي گرم در كيلوگرم). نتايج تاثير تيمارها بر شاخص هاي عملكرد در كل دوره مطالعه معني دار نبود. كمترين ميزان درصد تلفات آسيت، وزن قلب و تري يدوتيرونين (T3) در تيمار (25/6 ميلي گرم در كيلوگرم) مشاهده شد كه با تيمار شاهد تفاوت معني داري داشت (05/0

BACKGROUND: On account of the importance of iodine in the synthesis of thyroid hormones, different levels of dietary iodine can affect the occurrence of ascites syndrome in broilers. OBJECTIVES: The current research aimed to investigate the effects of different sources and levels of iodine on performance, carcass traits, ascites mortality, thyroid hormones, and serum biochemical parameters of broiler chickens under cold stress condition. METHODS: This experiment was performed using 375 one-day-old male broiler chickens in a completely randomized design with five treatments, five replications, and 15 birds per replication. To induce ascites, the room temperature was reduced to 15 °C from 14 days and this temperature was maintained until the end of the period. The experimental treatments included: control treatment (basal diet with iodine at the recommended level, 1.25 ppm), basal diet + potassium iodide (KI) with iodine levels (6.25 and 3.75 ppm), and basal diet + calcium iodate [Ca(IO3)2. H2O] with iodine levels (6.25 and 3.75 ppm). RESULTS: The effect of the treatments on the performance indices was not significant throughout the experiment. The lowest percentage of ascites mortality, heart weight, and triiodothyronine (T3) were observed in the treatment (6.25 ppm), which was significantly different from the control treatment (P<0.05). The lowest ratio of right ventricle to total ventricles (RV/TV) was related to potassium iodide treatment (6.25 ppm), which indicated tendency (P<0.10). Chickens receiving higher levels of iodine (6.25 ppm) had higher thyroxine than those receiving lower levels (3.75 ppm) (P<0.05) and showed a lower ratio of triiodothyronine to thyroxine compared to those (P<0.05). CONCLUSIONS: The results of this experiment implied that the use of higher levels of dietary iodine (6.25 ppm), especially as potassium iodide, reduces broiler’s ascites mortality under cold stress conditions.