Effect of cold water and inverse lighting on growth performance of broiler chickens under extreme heat stress

초록

The present study was carried out to investigate the effect of provision of extreme heat stress diet (EHD), inverse lighting, cold water on growth performance of broiler chickens exposed to extreme heat stress. The chickens were divided into four treatment groups, (T1, T2, T3, T4) as given below: T1 (EHD 1, 10:00-19:00 dark, 19:00-10:00 light, cool water 9 degrees C); T2 (EHD 2, 10:00-19:00 dark, 19:00-10:00 light, cool water 9 degrees C); T3 (EHD 1, 09:00-18:00 dark, 18:00-09:00 light, cool water 14 degrees C); T4 (EHD 2, 09:00-18:00 dark, 18:0009:00 light, cool water 14 degrees C. EHD 1 contained soybean oil, molasses, methionine and lysine; EHD 2 contained the same ingredients as EHD 1 with addition of vitamin C. Groups T1 and 12 were given cooler water than the other two groups, and displayed higher body weight increase and diet intake as compared to T3 and T4 (p<0.05). The weights of their liver and gizzard were similar but the weights of the thymus and bursa of fabricius (F) were higher in groups T1 and T2 (p<0.05). It was observed that groups T1 and T2 displayed higher concentrations of blood triglyceride, total cholesterol, HDL-cholesterol and blood sugar as compared to T3 and T4; however LDL-cholesterol level was higher in groups 13 and T4 (p<0.05). T1 and T2 displayed higher levels of immunity substances such as IgG, IgA and IgM as compared to T3 and T4, but the blood level of corticosterone was lower in groups T1 and T2 (p<0.05). T1 and T2 contained higher amount of fecal Lactobacill as compared to T3 and T4; however T3 and 14 contained higher amount of fecal E. coli, total aerobic bacteria and coliform bacteria (p<0.05). Groups T1 and T2 displayed higher concentrations of cecal total short chain fatty acids, acetic acid and propionic acid but groups T3 and T4 displayed higher concentrations of butyric acid, isobutyric acid, valeric acid and isovaleric acid (p<0.05). The present study reports novel results such that the supply of extreme heat stress diet, inverse lighting (10:00-19:00 dark, 19:00-10:00 light) with cold water at 9 degrees C under extreme heat stress could enhance growth performance of broiler chickens.

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