BACKGROUND: Optimal levels of minerals in the diet are crucial for improving performance and immune response against the environmental stresses.OBJECTIVES: This study was conducted to evaluate the effects of water supplementation of chelated trace mineral (CTM) on growth performance, hematology, blood biochemistry, antioxidant status, and antibody response in broilers reared under heat stress condition.METHODS: A total of 240 male Ross 308 broiler chickens were randomly allocated into one of the following five treatments (each consisting of four replicates): (1) positive control (PC; thermoneutral condition), (2) negative control (NC; heat stress condition), (3) low-CTM (NC + low CTM level in tap water), (4) medium-CTM (NC + medium CTM level in tap water),  and (4) high-CTM (NC + high CTM level in tap water). The CTM levels in the tap water for the low-CTM treatment were 0.1, 0.15, 0.3, 0.4, and 0.45 mg/bird/day on days 1-10, 11-20, 21-30, 31-40, and 41-50, respectively. The respective values were 1.0, 1.5, 3.0, 4.0, and 4.5 for the medium-CTM, and 10, 15, 30, 40, and 45 mg/bird/day for the high-CTM water.RESULTS: The average weight gain during the whole experimental period in the medium-CTM treatment was higher compared to that in the negative control treatment, but lower than that in the positive control treatment (P<0.05). The heterophil/lymphocyte ratio and total antibody titers against Newcastle disease in the medium-CTM and high-CTM groups were similar to those of the broilers in the PC group, yet better (P<0.05) those of the NC group. The serum superoxide dismutase activity was also higher (P<0.05) in the high-CTM group compared to that of the NC group.CONCLUSIONS: The results suggested that the water supplementation of CTM at a moderate level (1.0, 1.5, 3.0, 4.0, and 4.5 mg/bird/day during different rearing periods) could be a strategy to ameliorate the detrimental effects of heat stress in broilers.

BACKGROUND: There are different kinds of phytase from different sources used in poultry nutrition.OBJECTIVES: The present study aimed to evaluate the effects of addition of 2 sources of 6- phytase to the diet of male broilers in terms of growth performance, Tibia biometric, breacking straight, mineralization, blood biochemical parameters, and carcase yield.METHODS: Herein, we recruited 216 1-d-old male Ross broilers and divided them to three experimental groups and six replications for 42 D. The treatment (T) diets included: T1 (without phytase (control)), T2 (supplemented with 500 FTU/kg diet of Aspergillus niger phytase (fungi phytase)), T3 (supplemented with 500 FTU/kg diet of phytase produced by a genetically modified strain of Aspergillus oryzae by doner Citrobacter braakii gene (genetically modified phytase)).RESULTS: Serum P in the birds supplemented by genetically modified phytase was higher compared with that in the control birds (P<0.05). Additionally, Tibia P in this group was higher than that of birds supplemented by fungi phytase (P<0.05). However, Tibia breaking straight in birds supplemented by genetically modified phytase did not differ significantly with those fed with a diet with fungi phytase. Meanwhile, Tibia breaking straight in birds supplemented by genetically modified phytase was higher than control (P<0.05). Growth performance, Tibia length, diameter, ash, Ca, dry weight, average serum HDL, Triglyserid, Cholesterol, Ca, Alkalin phosphatase, Glucose, Total Protein, and Carcase yeild were not significantly different among any of the treatments.CONCLUSIONS: Supplementation of male broilers diet with genetically modified phytase (500 FTU/kg), without any differences in terms of performance, could increase P of serum, P of Tibia and breacking straight of Tibia compared to supplementation diet with Aspergillus niger phytase.

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.