Different responses of broilers at low, high, or cyclic moderate-high temperatures to dietary sodium bicarbonate supplementation due to differences in dietary formulation

An experiment was carried out to study the interaction of dietary sodium bi carbonate (NaHCO3) supplementation with two different practical dietary for mulations on the performance of 3-6-week-old broilers maintained in constan t low (20 degreesC), constant high (31 degreesC), or diurnal cyclic moderat e-high (25 degrees -35 degreesC) temperature regimens. Dietary formulations using typical Australian feed ingredients and varying in protein sources w ere used with one diet containing only animal-source protein ingredients (D iet 1) and the other diet containing predominantly plant-source protein ing redients (Diet 2). Feed intake and bodyweight gain (BWG) of broilers expose d to constant high or diurnal cyclic temperature regimens were similar and significantly poorer than those of broilers exposed to low temperatures. Di etary supplementation with NaHCO3 had no significant overall effect on prod uction parameters but significant NaHCO3 x temperature and NaHCO3 x diet in teractions were observed for BWG. Sodium bicarbonate improved BWG at consta nt 31 degreesC, but not at constant 20 degreesC, or in the diurnal cyclic t emperature regimen. Sodium bicarbonate significantly improved BWG with Diet 2 (plant-source proteins), which contained an arginine : lysine ratio of 1 .31 but not with Diet 1 (animal-source proteins), which contained an argini ne : lysine ratio of 1.01.