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标题：Effects of Applying Exogenous, Non-Starch Polysaccharidases to Pre Weaning Starter Concentrate on Performance of Holstein Calves
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作者：G.R. Ghorbani ; A. Jafari ; A.H. Samie 等
期刊名称：International Journal of Dairy Science
印刷版ISSN：1811-9743
电子版ISSN：1811-9751
出版年度：2007
卷号：2
期号：1
页码：79-84
DOI：10.3923/ijds.2007.79.84
出版社：Academic Journals Inc., USA
摘要：Scarcity of data exists on potential use of exogenous enzymes for young calves. The objective of this study was to assess the effects of applying Exogenous Non-starch Polysaccharidases (ENP) to pre-weaning starter concentrate on starter intake, nutrient digestibility and calf growth. Eighteen neonatal Holstein calves (47.9±2.5 kg body weight) were monitored for 84 day. Treatments included pre-weaning calf starters with 1) no enzyme additives (C), 2) enzyme additive A (EA, 0.6 mL kg^-1 starter), or 3) enzyme additive B (EB, 1.9 mL kg^-1 DM of starter). The activity of endo-cellulase, exo-cellulase and xylanase was measured using carboxymethyl cellulose, filter paper test and oat spelt, as the respective substrates. The resulting activity (μ mol/mL/min) of exo-cellulase, endo-cellulase and xylanase were respectively 1437, 788 and 7476 for EA and 1446, 1350 and 5091 for EB. No enzymes were added to post-weaning diet. Weaning Criterion (WC) was defined as the calf age at a daily intake of 680 g starter and estimated with regression equations. Mixed models of repeated measures with best fitted covariance structures were used to analyze the data. The calves fed EA-supplemented starter had higher NDF apparent total tract digestibility at week-4, but not at week-8, compared to control and EB-fed calves. However, NDF digestibility was lower at week-12 in ENP-fed calves than in control calves. The ENP did not affect the average daily starter intake, growth rate and WC. Overall, applying ENP to pre-weaning calf starter did not improve calf performance in this study. Further studies preferably using a mixture of cell-content and cell-wall polysaccharidases in both pre- and post-weaning starters would be warranted.