Effects of feeding time with betaine diet on growth performance, blood markers, and short chain fatty acids in meat ducks exposed to heat stress.

The objective of this study was to determine effect of the diet containing 1200 betaine diet on blood biomarkers, electrolytes, gas and cecum short-chain fatty acid profile in meat ducks exposed to very hot environment (high relative humidity) conditions from d 21–42 (11:00 to 17:00 h; 33–43 °C; 70% relative humidity). On the day of hatching, a total of 320 meat ducks(average, 48.6 g body weight) were randomly assigned to 4 treatments with 4 pens per treatment and 20 ducks per pen for 42 d. Dietary treatments consisted of: 1) the control diet fed ad libitum, 2) the betaine diet fed ad libitum, 3) the betaine diet fed from 05:00 to 10:00 and 17:00 to 20:00 h, and 4) the betaine diet fed from 17:00 to 20:00 h. Ducks fed the betaine diets had greater body weight at d 42 than those fed the control diet ( P <0.05). The total red blood cell counts, hematocrit, hemoglobin, mean corpuscular volume, red cell distribution width, platelet count, plateletcrit and mean platelet volume concentration in ducks fed the control diet were lower than those fed the betaine diets ( P <0.05). Blood electrolyte concentrations in ducks fed the betaine diet at different feeding times had greater values than those fed the control diet ( P <0.05). Partial pressure of carbon dioxide, partial pressure of oxygen, base excess of extracellular fluid, bicarbonate and total carbon dioxide concentrations in ducks fed the control diets were lower than those on the betaine treatments ( P <0.05). Respective to ducks fed the betaine diets had greater concentrations of total SCFA, acetic acid, propionic acid in the cecum than those fed the control diet ( P <0.05). However, ducks fed the betaine diets had lower levels of butyric acid, isobutyric acid, valeric acid, isovaleric acid than those fed the control diet ( P <0.05). The body weight, feed intake, sodium, hematocrit, hemoglobin, base excess of extracelluar fluid, mean corpuscular volume in ducks fed the betaine diet from fed 05:00 to 10:00 and 17:00 to 20:00 h were greater ( P <0.05) than those fed the betaine diet ad libitum and from 17:00 to 20:00 h. The results of this study indicated that restricted feeding of the diet with 1200 ppm betaine in morning and afternoon can have beneficial effects on meat ducks exposed to the very hot environment (high relative humidity) condition. [ABSTRACT FROM AUTHOR]