Effects of high temperature on multiple parameters of broilers in vitro and in vivo.

The effects of high temperature on multiple parameters of broilers were evaluated both in vitro and in vivo. In the in vitro study, the bilateral musculus fibularis longus muscles of 8 broilers were isolated and incubated at either 41.5 or 44.5 degrees C. The greater incubation temperature increased mitochondrial H2O2 production by 28.0% (P < 0.0001), malondialdehyde concentration by 16.8% (P = 0.0368), and lactate concentration by 33.0% (P < 0.0001) and decreased mitochondrial Ca2+-ATPase activity by 19.6% (P = 0.0001). In the in vivo study, 180 four-week-old broilers were kept in 3 controlled-environment chambers for 3 wk. High temperature increased mitochondrial H2O2 production (P < 0.05) in liver, malondialdehyde concentration in liver and breast muscle, and lactate concentration in breast muscle (P < 0.05). In addition, it inhibited mitochondrial Ca2+-ATPase activity in muscle and liver (P < 0.05). High temperature also significantly decreased initial pH and increased L*, drip loss, and shear force of broiler breast muscle.