Influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets.
1. The influence of conditioning temperature on the performance, nutrient utilisation and digestive tract development of broilers fed on maize- and wheat-based diets was examined up to 21 d of age. The experimental design was a 2 × 3 factorial arrangement of treatments evaluating two grain types (maize and wheat) and three conditioning temperatures (60°C, 75°C and 90°C). Broiler starter diets, each based on one grain (maize or wheat), were formulated and pelleted at the three temperatures. 2. Increasing conditioning temperature decreased the body-weight gain and feed intake in wheat-based diets, but birds fed on maize-based diets conditioned at 60°C and 90°C had higher body-weight gain and feed intake than those fed on the diet conditioned at 75°C. Increasing conditioning temperature increased feed per body-weight gain in both grain-type diets but improved pellet durability index (PDI) only in wheat-based diets; PDI was unaffected in maize-based diets. 3. In wheat-based diets, increasing conditioning temperature decreased the ileal digestibility of nitrogen and starch. Ileal nitrogen digestibility of maize-based diets conditioned at 60°C and 90°C was higher than at 75°C. Starch digestibility was unaffected by conditioning temperature in maize-based diets. No effect of conditioning temperature was found for apparent metabolisable energy (AME). Increasing conditioning temperature decreased digestible protein and AME intakes in wheat-based diets but, in maize-based diets, birds fed on the diet conditioned at 75°C had lower digestible protein and AME intakes compared to those fed on diets conditioned at 60°C and 90°C. 4. Small intestine was longer in birds fed on diets conditioned at 75°C and 90°C compared with those fed on diets conditioned at 60°C. 5. Overall, the data suggest that while the effects of conditioning temperature on body-weight gain and feed intake of broilers to 21 d of age differed depending on the grain type, feed per body-weight gain was adversely affected by higher conditioning temperatures.
Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
M R
MR
Abdollahi
V
V
Ravindran
T J
TJ
Wester
G
G
Ravindran
D V
DV
Thomas
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology*; D041981:Gastrointestinal Tract / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology; D011134:Polysaccharides / Q000378:metabolism; D013696:Temperature; D014908:Triticum; D003313:Zea mays
D011134:Polysaccharides