Production and Physiological Parameters of Broiler Chickens Administered Chilled Drinking Water under High Ambient Temperature During Finisher Period

High environmental temperature is of great concern in production of broiler chickens in the tropics, and this experiment was conducted to evaluate the ameliorative effect of chilled drinking water on the production and physiological parameters of broiler chickens reared in the tropics. This ۵۶-day experiment contained ۳ treatments (T۰, T۱, and T۲), replicated ۳ times to contain ۱۶ birds per replicate. T۰ (control) was offered non-chilled drinking water without increasing ambient temperature; T۱ was offered non-chilled drinking water with an increased ambient temperature of ۳۰°C between ۱۱:۳۰ – ۱۵:۳۰ GMT, daily; T۲ was offered chilled drinking water (۸-۱۰ ºC) with the increased ambient temperature of ۳۰°C between ۱۱:۳۰ – ۱۵:۳۰ GMT, daily. The total body weight gain of the birds was similar (P>۰.۰۵) in T۰ and T۲, which were significantly (P<۰.۰۵) higher than that of T۱. Feed intake was significantly (P<۰.۰۵) higher in T۰ than in T۱ and T۲, which were similar (P>۰.۰۵), while feed conversion ratio (FCR) was significantly (P<۰.۰۵) higher in T۱ than in T۰ and T۲, which were similar (P>۰.۰۵). Water intake was significantly (P<۰.۰۵) higher in T۲ than in T۱, which was significantly (P<۰.۰۵) higher than the water intake of T۰ chickens. Hemoglobin (Hb) concentration and red blood cell (RBC) count were similar (P>۰.۰۵) between T۰ and T۲, which were significantly (P<۰.۰۵) higher than values for T۱. Packed cell volume (PCV), white blood cell (WBC), lymphocyte and platelet counts, and blood coagulation time were similar (P>۰.۰۱) between T۰ and T۲, which were significantly (P<۰.۰۱) higher than those of T۱. The serum globulin of T۰ chickens was similar (P>۰.۰۵) to that of T۲, but significantly (P<۰.۰۵) higher than the serum globulin of T۱ chickens, which was similar (P>۰.۰۵) to that of T۲. Serum sodium (Na+) and potassium (K+) ions were significantly (P<۰.۰۵) higher in T۰ than in T۱ and T۲, which were similar (P>۰.۰۵), while serum hydrogen carbonate ion (HCO۳-) was significantly (P<۰.۰۵) higher in T۲ than in T۱ which was similar (P>۰.۰۵) to that of T۰, and that of T۰ similar to that of T۲. Respiratory rate and cloacal temperature were significantly (P ≤ ۰.۰۱) different among the treatments (T۱>T۲>T۰), while body temperature was significantly (P<۰.۰۵) higher in T۱ than in T۰ and T۲, which were similar (P>۰.۰۵). Therefore, administering chilled drinking water (۸-۱۰ ºC) to broiler chickens during periods of high ambient temperature can ameliorate heat stress through improved FCR, weight gain, stabilization of blood parameters and constituents, and reduction of high respiratory rate, body, and cloacal temperatures.High environmental temperature is of great concern in production of broiler chickens in the tropics, and this experiment was conducted to evaluate the ameliorative effect of chilled drinking water on the production and physiological parameters of broiler chickens reared in the tropics. This ۵۶-day experiment contained ۳ treatments (T۰, T۱, and T۲), replicated ۳ times to contain ۱۶ birds per replicate. T۰ (control) was offered non-chilled drinking water without increasing ambient temperature; T۱ was offered non-chilled drinking water with an increased ambient temperature of ۳۰°C between ۱۱:۳۰ – ۱۵:۳۰ GMT, daily; T۲ was offered chilled drinking water (۸-۱۰ ºC) with the increased ambient temperature of ۳۰°C between ۱۱:۳۰ – ۱۵:۳۰ GMT, daily. The total body weight gain of the birds was similar (P>۰.۰۵) in T۰ and T۲, which were significantly (P<۰.۰۵) higher than that of T۱. Feed intake was significantly (P<۰.۰۵) higher in T۰ than in T۱ and T۲, which were similar (P>۰.۰۵), while feed conversion ratio (FCR) was significantly (P<۰.۰۵) higher in T۱ than in T۰ and T۲, which were similar (P>۰.۰۵). Water intake was significantly (P<۰.۰۵) higher in T۲ than in T۱, which was significantly (P<۰.۰۵) higher than the water intake of T۰ chickens. Hemoglobin (Hb) concentration and red blood cell (RBC) count were similar (P>۰.۰۵) between T۰ and T۲, which were significantly (P<۰.۰۵) higher than values for T۱. Packed cell volume (PCV), white blood cell (WBC), lymphocyte and platelet counts, and blood coagulation time were similar (P>۰.۰۱) between T۰ and T۲, which were significantly (P<۰.۰۱) higher than those of T۱. The serum globulin of T۰ chickens was similar (P>۰.۰۵) to that of T۲, but significantly (P<۰.۰۵) higher than the serum globulin of T۱ chickens, which was similar (P>۰.۰۵) to that of T۲. Serum sodium (Na+) and potassium (K+) ions were significantly (P<۰.۰۵) higher in T۰ than in T۱ and T۲, which were similar (P>۰.۰۵), while serum hydrogen carbonate ion (HCO۳-) was significantly (P<۰.۰۵) higher in T۲ than in T۱ which was similar (P>۰.۰۵) to that of T۰, and that of T۰ similar to that of T۲. Respiratory rate and cloacal temperature were significantly (P ≤ ۰.۰۱) different among the treatments (T۱>T۲>T۰), while body temperature was significantly (P<۰.۰۵) higher in T۱ than in T۰ and T۲, which were similar (P>۰.۰۵). Therefore, administering chilled drinking water (۸-۱۰ ºC) to broiler chickens during periods of high ambient temperature can ameliorate heat stress through improved FCR, weight gain, stabilization of blood parameters and constituents, and reduction of high respiratory rate, body, and cloacal temperatures.

Keywords:

Blood , Broiler chickens , Electrolytes , Growth Performance , Respiratory rate , Temperature