Functional characterisation of a recombinant xylanase from Pichia pastoris and effect of the enzyme on nutrient digestibility in weaned pigs
J He, J Yin, L Wang, B Yu and D Chen, 2010. British Journal of Nutrition. 103: 1507–1513
10-Feb-2011 (15 years 3 months 26 days ago)The xyn2 gene of a filamentous mesophilic fungus, Trichoderma reesei, coding xylanase 2 (Xyn2) was previously expressed in Pichia pastoris. In the present study, the recombinant Xyn2 was prepared from a 15 litre fermenter, and subsequently characterised. It has been confirmed to have a molecular mass of 21 kDa, an optimal pH of 6.0 and an optimal temperature of 60ºC. When tested using oat-spelt xylan, it showed a Km and catalytic rate constant (kcat) of 1.1 mg/ml and 512.4/s, respectively. Analysis of the products from oat-spelt xylan degradation confirmed that the enzyme was an endoxylanase with xylotriose and xylobiose as the main degradation products. The unprocessed Xyn2 was supplemented to a xylan-containing diet to determine its influences on performance and nutrient digestibilities by weaned pigs.
Twenty-four weaned pigs (Duroc x Landrace x Yorkshire) with an average initial body weight of 10.2 ± 0.35 kg were selected and randomly allotted to four dietary treatments (n=6) with equal numbers of males and females in each group. Treatments consisted of: (1) control without Xyn2 supplementation; (2) Xyn2 added at a concentration of 500 U/kg diet (LD); (3) Xyn2 added at a concentration of 1000 U/kg diet (MD); (4) Xyn2 added at a concentration of 1500 U/kg diet (HD). Pigs were housed individually in metabolism cages (0.7 x 1.5m) with woven wire flooring in an environmentally controlled room (22–24ºC) and were given ad libitum access to water through a water nipple. Pigs were hand-fed four times per d (08.00, 12.00, 16.00 and 20.00 hours) in bowl feeders to make sure fresh feed was available.
Results showed that the average body-weight gain increased 16.9% when piglets received Xyn2 at a concentration of 500 U/kg diet. There also was a positive (0.05 < P<0.10) effect on the digestibility values of crude protein, ash, Ca and acid-detergent fibre with Xyn2 supplementation.
It is concluded that the results obtained from the present study indicated that the recombinant Xyn2 is more suitable for use in the feed industry. A diet supplemented with the unprocessed enzyme at a lower level improves both the performance and nutrient digestibilities in weaned pigs. However, a proper process is needed to improve its potential benefits as a feed additive for piglet nutrition.
Twenty-four weaned pigs (Duroc x Landrace x Yorkshire) with an average initial body weight of 10.2 ± 0.35 kg were selected and randomly allotted to four dietary treatments (n=6) with equal numbers of males and females in each group. Treatments consisted of: (1) control without Xyn2 supplementation; (2) Xyn2 added at a concentration of 500 U/kg diet (LD); (3) Xyn2 added at a concentration of 1000 U/kg diet (MD); (4) Xyn2 added at a concentration of 1500 U/kg diet (HD). Pigs were housed individually in metabolism cages (0.7 x 1.5m) with woven wire flooring in an environmentally controlled room (22–24ºC) and were given ad libitum access to water through a water nipple. Pigs were hand-fed four times per d (08.00, 12.00, 16.00 and 20.00 hours) in bowl feeders to make sure fresh feed was available.
Results showed that the average body-weight gain increased 16.9% when piglets received Xyn2 at a concentration of 500 U/kg diet. There also was a positive (0.05 < P<0.10) effect on the digestibility values of crude protein, ash, Ca and acid-detergent fibre with Xyn2 supplementation.
It is concluded that the results obtained from the present study indicated that the recombinant Xyn2 is more suitable for use in the feed industry. A diet supplemented with the unprocessed enzyme at a lower level improves both the performance and nutrient digestibilities in weaned pigs. However, a proper process is needed to improve its potential benefits as a feed additive for piglet nutrition.