Effects Of Diets Conditioned At Different Temperatures On Pellet Quality And Growth Performance For Broilers

There are three parts in this study:1.Effect of different conditioning temperatures on feed processing and pellet quality; 2.Effect of corn-soybean based broiler diets conditioned at different temperatures on growth performance and apparent nutrient digestibility for broilers.3. Effect of corn-soybean based broiler diets conditioned at different temperatures on the activity of digestive enzyme and the intestinal mucosa morphology of broilers.The first part, graded levels of conditioning temperature (70℃,80℃,90℃), and corn-soybean based formulations were conditioned at these temperatures respectively to create pelleted diet by steam conditioning. The effect of different conditioning temperatures on feed processing and pellet quality were assessed using the degree of starch gelatinization, pellet durability index and reducing sugar content of pellet feed. Results showed that conditioning temperatures increased from 70℃to 90℃significantly increased the pellet starch gelatinization and pellet durability (P<0.01). Reducing sugar content of pellet feed significantly decreased as the conditioning temperature increased (P<0.01), illuminated that the rate of Maillard reaction increased as conditioning temperature increased significantly (P<0.01).The second part,288 Avian broilers averaging 52 g and 4d of age were allocated into 3 groups, each group had 6 replications with 16 broilers per replication to evaluate the effect of the corn-soybean based diets conditioned at 70℃,80℃and 90℃, respectively, on performance and apparent digestibility of nutrients for Avian broilers. Results indicated that the 70℃group had the highest apparent digestibility of crude protein inl-28days (P<0.05), but the apparent digestibility of other nutrients had no significant (P>0.05) difference. Most of the nutrients digestibility in 80℃group was higher than the other groups (P>0.05). There was no significant (P>0.05) difference in terms of feed intake and performance when Avian broilers fed diets conditioned at 70℃,80℃and 90℃, respectively. Conditioned with too high temperature could decrease the ADG and FCR. The performance of broilers and feed conversion decreased when conditioning temperature was above 80℃(P>0.05)The third part was conducted to investigate the effect of the corn-soybean based diets conditioned at 70℃,80℃and 90℃, respectively, on the activity of digestive enzyme and the intestinal mucosa morphology of broilers. The results showed that there was no significant (P>0.05) difference in terms of activity of amylase and trypsase in duodenum and jejunum, the height of villi and the crypt depth of small intestine when Avian broilers fed diets conditioned at 70℃,80℃and 90℃respectively. The 90℃group had the lowest activity of amylase and trypsase. When the temperature is 90℃, the crypt is deepest; duodenum and ileum are shorter than those processed at other temperatures.