Effects Of Dietary Riboflavin On Performance, Immune Functiand Fat Metabolism In Broilers Under High-temperature Summer Season

Three experiments were conducted to investigate the effects of dietary riboflavin on performance, immune function and fat metabolism in broilers under heat sterss. And explore on summer season Xinjiang broilers requirement of riboflavin198 Arbor Acres chickens of 1 days old were randomly divided into 6 groups. 33 chickens in every group.They were fed one of following diets①basal diet;②basal+ 3.6mg/kg riboflavin (1NRC);③basal+ 7.2mg /kg riboflavin(2NRC);④basal+14.4mg/kg riboflavin (4NRC);⑤basal+21.6mg/kg riboflavin (6NRC) ;⑥basal +28.8 mg/kg riboflavin (8NRC) .There were 5 experimental groups and Control groups.The broilers in cages were raised in an environment controlled room maintained at 30~38℃on summer season lighting for seven weeks.The results showed that:1. In the experimental conditions , Dietary levels of riboflavin on dry matter, crude fiber, ash, phosphorus utilization of broilers no significant impact ;Compared with the control group broilers Higher level of riboflavin( 26.4 mg/kg) increased crude protein utilization, Riboflavin addition at 19.2 mg/kg and 26.4 mg/kg level of riboflavin increased crude fat utilization2. Riboflavin addition to 33.6mg/kg increased the 7-28 days broilers daily weight gain, And significantly lower the 29-49 days of the Higher feed ;Riboflavin supplement no significant effect on broilers mortality ;Riboflavin supplement no decreased breathing rate of 21 days broiler. With broilers day old increasing,the higer dietary riboflavin (33.6mg/kg)decreased breathing rate of 28 days old broilers 16: 00 in high ambient temperature. the higer dietary riboflavin (26.4mg/kg) decreased breathing rate and rectal temperatur of 35days broilers in high ambient temperature (P<0.05).the dietary riboflavin (19.2mg/kg) decreased rectal temperature of 21,28broilers in high ambient temperature. Riboflavin addition at 26.4 mg/kg can be significantly enhanced 49-day relative thymus weight and Tibia bore full rate ;the highest IgG group is 26.4 mg/kg riboflavin Group , the highest IgA group is 33.6 mg/kg riboflavin Group3. Compared with the control group 26.4 mg/kg riboflavin Group can be significantly reduced the 28-day-old broiler subcutaneous fat thickness , 33.6 mg/kg riboflavin Group can be significantly reduced the 42-day-old broiler subcutaneous fat thickness and 49-day-old broiler intramuscular fat.