Abstract
Three experiments were conducted to study the property of xylanase and the effects of xylanase in wheat-based diets on growth performance of broilers, respectively. Experiment 1 was performed in vitro to evaluate the effect of different pH and temperature on xylanase activity, and to evaluate the enzymic stability under different conditions. The results indicated that the optimum temperature and pH for xylanase activity were 50°C and 4.5, respectively. The activity of enzyme solution was reduced rapidly after the treatment of water bath above 60°C for 10 min. The enzyme was relatively stable at pH 3.5 to 8.0 and deteriorated when incubated at pH below 3.5. In Experiment 2, a total of 378 d-old male Arbor Acres broilers were randomly distributed to 7 different treatments with 6 replicates (9 birds) in each treatment. The treatments were as follows: (1) corn based diet (CS), (2) wheat based diet (WS), (3) WS+ 0.05% xylanase, (4) WS+0.15% xylanase, (5) WS+0.25% xylanase, (6) WS+0.35% xylanase, (7) WS+0.45% xylanase. The results showed that the body weight and feed/gain ratio of the broilers fed wheat-based diets have been significantly improved (p 0.05) was found among all these different treatments. The supplementation of xylanase and the type of diets did not affect the feed intake but increased the concentration of triglyceride in serum. In Experiment 3, a total of 360 d-old male Arbor Acres broilers were assigned to 30 groups with 12 birds in each group randomly. These groups were then randomly distributed to 5 different treatments with 6 replicates within each treatment. The broilers of each treatment were fed one of the diets as follows: (1) Corn based diet, (2) White wheat based diet (WW) (3) White wheat based diet+0.25% xylanase, (4) Red wheat based diet, (5) Red wheat based diet+0.25% xylanase. The results showed that the body weight and feed/gain ratio had been significantly improved (p<0.05) by xylanase supplementation in the first 2 or 3 wk. The effect of xylanase in red wheat diet is a little higher than that used in white wheat diet. From the results of the present experiments, it can be concluded that the supplementation of Aspergillar xylanase can improve the performance of the broilers fed the wheat-based diet. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 1 : 66-74)
Highlights
Wheat is an important feed ingredient in poultry diets.it contains relatively high levels of arabinoxylans/pentosans at concentrations of 50-80 g/kg dry matter (Annison, 1991), making these the main non-starch polysaccharide (NSP) component
Bedford et al (1991) and Bedford and Classen (1992) demonstrated that a significant negative relationship exists between intestinal viscosity and feed conversion efficiency in chickens fed on rye and wheat based diets
The enzyme activity was maintained greater than 80% of its highest activity from pH 4.0 to 6.0
Summary
Wheat is an important feed ingredient in poultry diets.it contains relatively high levels of arabinoxylans/pentosans at concentrations of 50-80 g/kg dry matter (Annison, 1991), making these the main non-starch polysaccharide (NSP) component. Wheat is an important feed ingredient in poultry diets. It contains relatively high levels of arabinoxylans/. Pentosans are the main constituent in the endosperm cell wall of wheat, rye and triticale (Mares and Stone, 1973; Henry, 1985), and are assumed to have antinutritional effects on broiler chickens (Annison, 1991; Choct and Annison, 1990, 1992a). Bedford et al (1991) and Bedford and Classen (1992) demonstrated that a significant negative relationship exists between intestinal viscosity and feed conversion efficiency in chickens fed on rye and wheat based diets. Choct and Annison (1992b) confirmed that isolated wheat pentosans. Pentosans are the main constituent in the endosperm cell wall of wheat, rye and triticale (Mares and Stone, 1973; Henry, 1985), and are assumed to have antinutritional effects on broiler chickens (Annison, 1991; Choct and Annison, 1990, 1992a). Bedford et al (1991) and Bedford and Classen (1992) demonstrated that a significant negative relationship exists between intestinal viscosity and feed conversion efficiency in chickens fed on rye and wheat based diets. Choct and Annison (1992b) confirmed that isolated wheat pentosans
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