Characterization and evaluation of crude xylanase in wheat-based broiler chicken diets
2006
Billena, M.S.
Xylanases from ten different preparations were characterized and evaluated for their stability during storage at room temperature and their efficacy in broiler chicken diets. Results showed that xylanase activity of the ten preparations ranged from 76 to 30, 873 U/g solid or 38 to 1544 U/kg feeds. They had different optimum pH (4 or 5.3) and optimum temperature (50, 60, or 70 deg C), and were stable to pepsin and trypsin. However, the residual activities of most xylanases were reduced after 20 second exposure to 70 deg C. Among the three selected preparations, E was not affected while A and B showed significant decrease in xylanase activity after two months storage. On the other hand, all the xylanase preparations added in feeds were stable for one month storage. However, the recovery of xylanase activity in feeds was low. The efficacy of three selected xylanases in wheat-based broiler diets was evaluated following a 3 x 3 factorial design with control in CRD (3 preparations and 3 levels of xylanases). The xylanase activity in the gizzard was depressed but was active in other segments of the gastro-instestinal tract. The specific viscosity of the digesta from the jejunum and ileum of broilers fed xylanase supplemented diets were significantly decreased by increased level of supplementation up to 500 U/kg. Xylanase supplementation significantly increased AME but not crude protein digestibility of starter diets. Significant interaction between preparation and level of xylanase was observed on the AME of the starter diet. Xylanase supplementation improved body weight gain, feed efficiency, but not feed consumption of broilers. Broilers fed wheat-based diets containing the lowest level of supplementation (200 U/kg) gave the highest income over feed and chick cost.
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