Tricarico J M, Abney M D, Galyean M L, Rivera J D, Hanson K C, McLeod K R, Harmon D L
Alltech Biotechnology Inc., Nicholasville, KY 40356, USA.
J Anim Sci. 2007 Mar;85(3):802-11. doi: 10.2527/jas.2006-427. Epub 2006 Nov 22.
Three experiments were conducted to examine the effects of an Aspergillus oryzae extract containing alpha-amylase activity on performance and carcass characteristics of finishing beef cattle. In Exp. 1, 120 crossbred steers were used in a randomized complete block design to evaluate the effects of roughage source (alfalfa hay vs. cottonseed hulls) and supplemental alpha-amylase at 950 dextrinizing units (DU)/kg of DM. Significant roughage source x alpha-amylase interactions (P < 0.05) were observed for performance. In steers fed cottonseed hulls, supplemental alpha-amylase increased ADG through d 28 and 112 and tended (P < 0.15) to increase ADG in all other periods. The increases in ADG were related to increased DMI and efficiency of gain during the initial 28-d period but were primarily related to increased DMI as the feeding period progressed. Supplemental alpha-amylase increased (P = 0.02) the LM area across both roughage sources. In Exp. 2, 96 crossbred heifers were used in a randomized complete block design with a 2 x 3 factorial arrangement of treatments to evaluate the effects of corn processing (dry cracked vs. high moisture) and supplemental alpha-amylase concentration (0, 580, or 1,160 DU/kg of DM). Alpha-amylase supplementation increased DMI (P = 0.05) and ADG (P = 0.03) during the initial 28 d on feed and carcass-adjusted ADG (P = 0.04) across corn processing methods. Longissimus muscle area was greatest (quadratic effect, P = 0.04), and yield grade was least (quadratic effect, P = 0.02) in heifers fed 580 DU of alpha-amylase/kg of DM across corn processing methods. In Exp. 3, 56 crossbred steers were used in a randomized complete block design to evaluate the effects of supplemental alpha-amylase (930 DU/kg of DM) on performance when DMI was restricted to yield a programmed ADG. Alpha-amylase supplementation did not affect performance when DMI was restricted. We conclude that dietary alpha-amylase supplementation of finishing beef diets may result in increased ADG through increased DMI under certain dietary conditions and that further research is warranted to explain its mode of action and interactions with dietary ingredients.
进行了三项试验，以研究含有α-淀粉酶活性的米曲霉提取物对育肥牛生长性能和胴体特性的影响。在试验1中，120头杂交阉牛采用随机完全区组设计，以评估粗饲料来源（苜蓿干草与棉籽壳）和添加950糊精化单位（DU）/千克干物质的α-淀粉酶的效果。观察到粗饲料来源×α-淀粉酶之间存在显著的互作效应（P<0.05），对生长性能产生影响。在饲喂棉籽壳的阉牛中，添加α-淀粉酶在第28天和第112天提高了平均日增重（ADG），并且在所有其他时间段均有提高ADG的趋势（P<0.15）。ADG的提高在最初的28天内与干物质采食量（DMI）增加和增重效率提高有关，但随着饲喂期的延长，主要与DMI增加有关。添加α-淀粉酶使两种粗饲料来源的背最长肌面积均增加（P=0.02）。在试验2中，96头杂交小母牛采用随机完全区组设计，进行2×3析因处理安排，以评估玉米加工方式（干破碎与高水分）和添加α-淀粉酶浓度（0、580或1160 DU/千克干物质）的效果。在最初的28天饲喂期内，添加α-淀粉酶提高了DMI（P=0.05）和ADG（P=0.03），并且在两种玉米加工方式下均提高了胴体校正后的ADG（P=0.04）。在两种玉米加工方式下，饲喂580 DUα-淀粉酶/千克干物质的小母牛，其背最长肌面积最大（二次效应，P=0.04），产量等级最低（二次效应，P=0.02）。在试验3中，56头杂交阉牛采用随机完全区组设计，以评估当DMI受限以达到设定的ADG时，添加α-淀粉酶（930 DU/千克干物质）对生长性能的影响。当DMI受限时，添加α-淀粉酶对生长性能没有影响。我们得出结论，在某些日粮条件下，育肥牛日粮中添加α-淀粉酶可能通过增加DMI来提高ADG，并且有必要进一步研究以解释其作用方式以及与日粮成分的相互作用。
