Choct M, Kocher A, Waters D L E, Pettersson D, Ross G
School of Rural Science and Agriculture, University of New England, Armidale, NSW 2351, Australia.
Br J Nutr. 2004 Jul;92(1):53-61. doi: 10.1079/BJN20041166.
Three xylanase products, xylanase A derived from Thermomyces lanuginosus, xylanase B from Humicola insolens and xylanase C from Aspergillus aculeatus, were examined for their effects on the nutritive value of wheat. The study investigated the effects of enzyme addition to broiler diets based on a low-metabolisable-energy (ME) wheat and a normal-ME wheat, with the emphasis on changes in composition of the NSP along the digestive tract in broiler chickens. There were significant (P<0.01) enzyme and wheat effects on the apparent ME, but there was no wheat x enzyme interaction on apparent ME. Weight gain and feed conversion efficiency (except xylanase C for normal wheat) were also significantly (P<0.01) increased by the xylanases. The enzymes differed in their effect on a number of important nutritional parameters. Xylanase A reduced (P<0.05) the excreta moisture level from 77.1 % in birds fed the normal-ME wheat control to 73.4 % and from 77.4 % in those fed the low-ME wheat to 73.0 %. The other two enzymes did not affect excreta moisture levels. The digesta viscosity in the duodenum, jejunum and ileum of birds fed both types of wheat was reduced (P<0.01) by xylanases A and C, but was increased (P<0.01) in the jejunum and ileum by xylanase B. The digestibility of the soluble NSP was mostly negative in the small intestine. The digestibility of the insoluble NSP differed (P<0.01) between the two wheats, with those in the low-ME wheat being more digestible (14 v. 28 %). When supplemented with xylanase A, the ileal digestibility of the insoluble NSP in the normal- and low-ME wheats was increased by 28 and 42 %, respectively. Xylanases B and C did not affect the digestibility of the insoluble NSP regardless of wheat type. It may be concluded that wheats with low or normal ME values vary in their responses to xylanase supplementation. Apart from having an elevated level of soluble NSP, low-ME wheat may also contain insoluble NSP, which in the present study appeared to be more easily degradable in the gut of the chicken.
研究了三种木聚糖酶产品，即源自嗜热栖热菌的木聚糖酶A、特异腐质霉的木聚糖酶B和棘孢曲霉的木聚糖酶C对小麦营养价值的影响。该研究调查了在基于低代谢能（ME）小麦和正常ME小麦的肉鸡日粮中添加酶的效果，重点关注肉鸡消化道中NSP组成的变化。酶和小麦对表观代谢能有显著（P<0.01）影响，但在表观代谢能方面不存在小麦×酶的交互作用。木聚糖酶也显著（P<0.01）提高了体重增加和饲料转化效率（正常小麦组中木聚糖酶C除外）。这些酶对一些重要营养参数的影响存在差异。木聚糖酶A使正常ME小麦对照组鸡的粪便水分含量从77.1%降至73.4%，使低ME小麦组鸡的粪便水分含量从77.4%降至73.0%（P<0.05）。另外两种酶对粪便水分含量没有影响。木聚糖酶A和C降低了（P<0.01）两种小麦日粮组鸡十二指肠、空肠和回肠的食糜黏度，但木聚糖酶B使空肠和回肠的食糜黏度升高（P<0.01）。可溶性NSP在小肠中的消化率大多为负值。两种小麦中不溶性NSP的消化率存在差异（P<0.01），低ME小麦中的不溶性NSP更易消化（分别为14%和28%）。添加木聚糖酶A后，正常ME小麦和低ME小麦中不溶性NSP的回肠消化率分别提高了28%和42%。无论小麦类型如何，木聚糖酶B和C对不溶性NSP的消化率均无影响。可以得出结论，低ME值或正常ME值的小麦对木聚糖酶添加的反应有所不同。低ME小麦除了可溶性NSP水平较高外，可能还含有不溶性NSP，在本研究中，这些不溶性NSP在鸡肠道中似乎更容易降解。
