Effects Of Extruded Corn And Exogenous Amylase On Starch Metabolism In Weaned Pigs

A series of seven trails were conducted to investigate the effects of extruded corn (EC) and exogenous amylase on starch metabolism and intestinal morphology in weaned pigs. Firstly, the optimal processing parameters for extruded corn and the difference of nutritional values, morphology shape and crystal structure of starch granules between extruded and raw corn were studied. Meanwhile, the apporoparite additional level of EC in diets for weaned pigs and the relationship between amylase activity and the starch vitro hydrolization degree were investigated. Then the effect of EC and amylase supplementation (AS) in diets on performance, blood parameters and nutritional availability for weanded pigs were investigated systematically. Finally, the effects of above two treatments on activity of carborhydrate digestible enzyme and intestinal morphology for weaned pigs were investigated. The results summarized as follows:1. Study on processing parameters of extruded cornObjective: Detemine the optimal processing parameters for extruded corn. Methods: Using the new raw corn from Henan province to study the effect of differient extruder sleeve temperature, screw speed, feeding speed and material moisture on expanding degree, starch gelatinization degree and available lysine contents of EC. Accordingly, we can determine the optimal processing parameters for EC.Results: (1) When tempreture of the extruder sleeve was lower than 110°C, with the increasing of temperature, the expanding degree and starch gelatinization degree of EC were increased, but the avilable lysine content did not change. When the temperature was 110°C, the expanding degree and starch gelatinization degree got highest. When the temperature was higher than 110°C, with the increasing of extrusion temperature, the expanding degree and starch gelatinization degree decreased. The avilable lysine content droped obviosly. (2) With the screw rotated faster, the expanding degree and starch gelatinization degree had a tendency to decrease, but the avilable lysine content did not change. (3) With the feeding speed increased, the expanding degree and starch gelatinization degree decreased and the avilable lysine content did not change. (4) When the moisture of corn was below 21%, the expanding degree and starch gelatinization degree increased and the avilabal lysine content fall down with the increasing of material moisture. When the moisture was 21%, the expanding degree and starch gelatinization degree got highest. When the moisture was more than 21%, with the material got more and more wet, the expanding degree and starch gelatinization degree decreased and the...