Exposing broilers to a high temperature increases water and electrolyte K(+) and Na(+) excretion, which negatively affects the heat dissipation capacity and acid-base homeostasis, resulting in losses in growth performance. In this experiment, the efficacy of providing oral rehydration therapy and betaine on growth performance, acid-base balance, and water and electrolyte retention was evaluated. A total of 432 one-day-old broiler chicks (Cobb) were allocated to 72 metabolic cages and reared to 31 d of age under standard conditions. From 32 to 41 d of age, chicks were exposed to heat stress (ambient temperature, 32 C) and high RH (80 to 100% RH) for 9 h daily. The ameliorative effects of a 3 x 3 factorial array of treatments administered via drinking water were evaluated in 8 replicates of 6 chicks per cage for each treatment. Two oral rehydration therapy (ORT) fluids, based on either citrate or bicarbonate salts, were added to tap water. In addition, betaine was added to tap water at an inclusion rate of 0, 500, or 1,000 mg/L to complete the array of 9 liquid-based treatments. Growth performance was assessed at 32, 35, and 41 d of age. From 32 to 35 d of age, chicks receiving ORT fluids exhibited improved growth performance, water balance, and electrolyte (K(+), Na(+)) retention. In addition, the physiological response to stress was attenuated, as indicated by lower heterophil-to-lymphocyte ratios and blood glucose concentrations relative to the negative controls. The addition of betaine at an inclusion rate of 500 mg/L improved BW gain. From d 36 to 41, treatments did not significantly influence growth performance, which suggests that chicks receiving tap water were able to compensate and adapt to the heat-stress conditions. The results demonstrate that the beneficial effects of providing ORT fluids and 500 mg of betaine/L were observed only during the first 4 d of heat exposure. After this period, adaptation to the heat appears to occur, and none of the treatments was successful in improving growth performance.

Studies the Variation in certain biological aspects of cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) in relation to color of its forms.

Studies the Variation in certain biological aspects of cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) in relation to color of its forms.

Studies the Variation in certain biological aspects of cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) in relation to color of its forms.

The effects of dietary electrolyte balance (DEB) and electrolyte-betaine (El-Be) supplements on heat-stressed broiler performance, acid-base balance and water retention were evaluated during the period 31-40d of age in a 2x3 factorial arrangement of treatments. A total of 240 broilers were assigned to 6 treatment groups each with 8 replicates of 5 birds per cage and were exposed to cyclic high temperature (32-24 +/- 1 degrees C). Birds were provided with diets having DEB of either 180 or 220mEq/kg. El-Be supplements were either added to the diet, water or not added to either of them to complete the array of 6 treatment groups. An additional 80 birds were kept at thermoneutral temperature (20 +/- 1 degrees C) and were provided with tap water and diets with DEB of either 180 or 220mEq/kg to serve as negative controls. Exposure to high temperature depressed growth performance, increased rectal temperature and decreased potassium (K+) retention. In high-temperature room, birds fed on diets with DEB of 220mEq/kg tended to increase BW from 35-40d of age. However, at thermoneutral temperature, broilers fed on diets with DEB of 220mEq/kg increased K+ retention. Adding El-Be supplements in feed or water improved feed conversion ratio (FCR), enhanced water consumption and increased K+ and sodium (Na+) retention. Interactions between DEB and El-Be supplements tended to affect body weight gain and FCR during the periods 35-40 and 31-40d of age, respectively. It is suggested that when using a diet with DEB of 180mEq/kg, adding the El-Be supplements in drinking water was more beneficial than in feed. Adding the supplements in feed or water was equally useful when using DEB of 220mEq/kg.