摘要
Forty crossbred steers (Baladi×Friesian, average BW 153±5.14 kg) were used to evaluate the effects of exogenous enzyme (ENZ) addition on nutrient intake, digestion, ruminal fermentation and feed conversion in beef steers. Steers were randomly assigned to two groups of 20 animals and fed individually a total mixed ration (TMR) without (CTRL) or with addition of 40 g/hd/d of an enzyme mixture (ZADO®). The ENZ mixture was added for 220 days and in vivo apparent digestibility was measured on days 210–220. Enzyme addition did not affect (P=0.1) DM intake, whereas it increased (P<0.05) total tract apparent digestibility of all nutrients. The magnitude of improvement in digestibility varied among nutrients, with the highest improvement occurring in digestibility of NDF and ADF (21.8% and 26.7%, respectively). Addition of ENZ also increased (P<0.05) concentrations of rumen ammonia N and total short chain fatty acids (SCFA) before and 3 h post-feeding. Allantoin concentration total purine derivates were increased (P=0.04) with enzyme addition while uric acid was not affected (P=0.05). Live-weight gain was also higher (P<0.01) in steers supplemented with ENZ. In conclusion, adding the exogenous enzyme product increased live-weight gain by 16% due to increased nutrient digestibility.
摘要译文
四十三元杂交肉牛（巴拉迪×黑白花，平均体重153±5.14千克）被用来评价外源性酶（ENZ）除了对营养物质的摄入，消化的效果，瘤胃发酵和牛肉肉牛饲料转化率。阉牛被随机分配到两个组的20只动物，并分别送到一个全混合日粮（TMR）无（CTRL）或通过加入的酶混合物为40克/头/ D（ZADO SUP该ENZ混合物中加入220天，并在体内表观消化率上测量天210-220。加入酶没有影响（P \x3d 0.1）干物质采食量，而它增加（P05）的总消化道表观所有营养物质消化率。改善的消化率的幅度营养成分各不相同，最高的改善发生在NDF和ADF（分别为21.8％和26.7％，）的消化率。此外ENZ也增加（P05）的前瘤胃氨N和总短链脂肪酸（SCFA）和3小时后的摄食浓度。尿囊素浓度嘌呤总量分别衍生物增高（P \x3d 0。04）用酶加成而尿酸不受影响（P \x3d 0.05）。活体重增加也较高（P16％，由于增加养分消化率添加外源性酶制剂产品增加活体重增加。
A.Z.M. Salem[a][d]; H.M. Gado[b]; D. Colombatto[c]; M.M.Y. Elghandour[a]. Effects of exogenous enzymes on nutrient digestibility, ruminal fermentation and growth performance in beef steers[J]. Livestock Science, 2013,154(1-3): 69–73