Abstract
This study was conducted to investigate the effects of ambient temperature on the growth performance, fat deposition, and intestinal morphology of geese from 28 to 49 d of age. A total of 120 twenty-eight-day-old geese were randomly allotted to 5 environmentally controlled chambers with ambient temperatures set at 18, 21, 24, 27, and 30°C from 28 to 49 d of age, respectively. The feed intake, 49 d body weight, and weight gain decreased linearly or quadratically (P < 0.05) as ambient temperature increased and declined to a minimum when the temperature increased to 30°C. The feed/gain showed a linear or quadratic (P < 0.05) increasing response to increasing temperature. According to broken-line regression, the upper critical levels of ambient temperature from 28 to 49 d of age for weight gain and feed intake were 25.19 and 23.97°C, respectively. As ambient temperature increased from 18 to 30°C, the abdominal fat weight, abdominal fat rate, and subcutaneous fat thickness decreased linearly (P < 0.05) and were accompanied by linearly increasing liver fat content (P < 0.05), but the ambient temperature had no effect on intermuscular fat width or breast muscle fat content (P > 0.05). There were no differences in jejunal, ileal, or cecal morphology for geese raised at 18, 21, 24, 27, and 30°C (P > 0.05). The duodenal villus height showed a linear decreasing response to increasing ambient temperature, but the ambient temperature had no effect on crypt depth, villus width, muscularis thickness, or villus height/crypt depth of the duodenum (P > 0.05). These results indicate that high ambient temperature decreased growth performance and fat deposition and impaired duodenal morphology of geese. Under our experimental conditions, we recommend that the upper critical ambient temperature for geese from 28 to 49 d of age be 25.19°C.