The Study Of Stability Of Feed Xylanase Activity

Objective of the study is to evaluate stability of liquid xylanase during treatment at different temperature and time, influence of feed ingredients on activity of solid xylanase, thermal stability of solid xylanase by in vitro evaluation methods. The influence of feed ingredients on thermal stability of solid xylanase had been also studied. The pentosan content of ordinary feed ingredients, basic characteristics of xylanase and effect of xylanase on wheat break down in vitro were reported. Recommendation on how to evaluate feed xylanase performance was given based on animal digestive tract.The results showed as follows: the treatment (up to 72h) had no significant effect on liquid xylanase activity when the temperature below 15℃(p>0.05). However, when temperature is over than 25℃, the treatment would significantly affect liquid xylanase activity (p<0.05). As the temperature or time increases, the loss of xylanase activity would accelerate and activity of xylanase was significantly higher than the value measured after refrigeration.During the mixing, except premix, solid feed ingredients, such as corn, wheat, CSM, RSM and SBM, had no effect on xylanase activity (p>0.05). However, activity of solid xylanase could significantly reduce by mixed with liquid feed ingredients, such as molasses, soybean oil and poultry fat (p<0.05).Evaluated thermal stability of solid xylanase by in vitro evaluation methods between 75 to 95℃, the results have shown that there were significantly affected by different samples, temperature and methods (p<0.05). These in vitro laboratory methods have their own scope and couldn't reflect the true affect of feed processing on xylanase activity. During the pelleting, solid feed ingredients had no significant influence on thermal stability of xylanase, such as corn, wheat and SBM (p>0.05). Liquid feed ingredients could significantly improve xylanase thermal stability and reduced activity loss, such as molasses, soybean oil and poultry fat (p<0.01).The pentosan content in feed ingredients was reported in the paper. Activity of xylanase and effect of xylanase on wheat were significantly affected by processing temperature and pH. Based on animal digestive tract, 40℃as the standard reaction temperature together with the curve of xylanase activity in different pH should be a possible useful in vitro evaluation method on feed xylanase performance.