链霉菌F0107液体发酵产木聚糖酶条件的优化

运用透明圈法从土样中筛选出产木聚糖酶放线菌80余株.对其中一株产酶情况较稳定的链霉菌菌株F0107进行了液体发酵的碳源、氮源、初始pH值、摇床转速及培养温度等条件的优化.实验表明,此菌株最适碳源为玉米芯水不溶性木聚糖,最适氮源为酵母浸膏与蛋白胨的复合氮源,最适初始pH值为5.0,最适产酶温度和最适摇床转速分别为32℃和140 r/min.质量分数为0.4%的吐温80使菌株木聚糖酶产量提高41%,发酵条件优化后,链霉菌F0107所产的木聚糖酶活力达332.17 U/mL,产量是优化条件前的2.5倍.在此条件下链霉菌F0107主要产生相对分子质量约为38.9 ku和24.4 ku的木聚糖酶.     

小麦饲粮中添加木聚糖酶对肉鹅血糖和血清总蛋白水平的影响

[目的]研究在小麦饲粮中添加木聚糖酶对肉鹅血糖和血清总蛋白水平的影响。[方法]以1日龄健康肉用雏鹅为材料,采用单因子随机化设计,分6组分别饲喂玉米型、小麦型饲粮及添加不同浓度木聚糖酶的小麦饲粮,测定血液中血糖和血清总蛋白的含量。[结果]小麦饲粮中添加木聚糖酶能够提高肉鹅血糖和血清总蛋白水平,添加量为0.2%时效果最佳,高于玉米对照组水平;对血清蛋白浓度,0.2%添加组与小麦组和玉米组的差异均达到显著水平。[结论]在饲料中添加木聚糖可提高肉鹅的生产水平。     

金属离子对灵芝纤维素酶和木聚糖酶活性的作用

研究了6种金属离子对灵芝纤维素酶和木聚糖酶活性的影响。结果表明：在试验的离子浓度范围内,Mn2＋抑制灵芝纤维素酶的CMC酶活、FP酶活和木聚糖酶活;Zn2＋抑制灵芝FP酶活和木聚糖酶活,却促进CMC酶活;Mg2＋对纤维素酶的CMC酶活和FP酶活有明显的促进作用,但浓度高时会抑制木聚糖酶活;Cu2＋在低浓度时,激活灵芝产的木聚糖酶,其他浓度会抑制纤维素酶活性及木聚糖酶酶活;K＋对纤维素酶的CMC酶活和FP酶活促进作用小,对木聚糖酶活的抑制作用也小;Fe2＋抑制CMC酶活,低浓度抑制FP酶活,高浓度抑制FP酶活,对木聚糖酶活性的作用却相反。     

Effect of Wheat Based Diet Supplemented with Xylanase on Blood Sugar and Total Protein in Serum of Geese

[Objective] The effects of wheat based diet supplemented with xylanase on blood sugar and total protein in serum of geese were studied. [Method] By using the randomized design of single factor,the 1-day-old healthy goslings were divided into 6 groups and fed with corn based diet,wheat based diet and wheat based diet supplemented with xylanase at different concentrations respectively,the contents of blood sugar and total protein in serum were determined. [Result] The wheat based diet supplemented with xylanase could increase the blood sugar and total protein in serum of geese and wheat based diet supplemented with 0.2% xylanase generated the best effect,which was higher than those of corn based diet group. As for the concentration of protein in serum,wheat based diet supplemented with 0.2% xylanase was significantly different from corn based diet and wheat based diet. [Conclusion] The wheat based diet supplemented with xylanase could enhance geese production.     

皖麦38添加木聚糖酶对鸡表观代谢能值和氨基酸表观消化率的影响

用32只小公鸡进行代谢试验，研究高戊聚糖含量小麦品种皖麦38添加木聚糖酶对鸡表观代谢能值（AME）和氨基酸表观消化率的影响。结果显示，木聚糖酶使鸡的表观代谢能值（干物质基础）提高4．14％（P＜0．05），干物质消化率提高5．98％（P＜0．05），有机物消化率提高5．36％（P＜0．05），粗脂肪消化率提高3．01％（P＞0．05）。氨基酸表观消化率分析表明，木聚糖酶对赖氨酸和天冬氨酸的消化率分别提高5．19％（P＞0．05）和5．00％（P＞0．05）；组氨酸和脯氨酸的消化率分别提高3．67％（P＜0．05）和2．39％（P＜0．05）；亮氨酸、精氨酸、缬氨酸、丙氨酸、胱氨酸的消化率分别提高2．12％－4．18％不等；对其它氨基酸的消化率没有明显影响。     

纤维素分解菌的筛选及玉米秸秆降解

从不同来源的土样中分离出降解纤维素能力强的5株霉菌及5株放线菌,测定了这10株菌在玉米秸秆发酵中的CMC酶及木聚糖酶的动态酶活。结果表明,霉菌菌株F6在整个培养过程中CMC酶及木聚糖酶的活性最高,分别为14.57和25.69 U/g,其次为放线菌A4,CMC酶及木聚糖酶酶活分别为8.62、27.07U/g。采用F6,A4处理玉米秸秆15 d,降解率分别达44.80%和41.12%。进一步研究表明,接种不同菌株后的玉米秸秆降解率与降解过程中菌株产CMC酶及木聚糖酶最大酶活呈显著的正相关关系。     

Influence of phytase and xylanase supplementation of a wheat-based diet on ileal and total tract digestibility in growing pigs

The effect of phytase and xylanase supplementation of a wheat-based pig diet on the ileal and total tract apparent digestibility of dietary components and minerals were studied in eight growing pigs fitted with a PVTC cannula in a randomized block design experiment. The diets (A and B) were similar in major ingredient composition and in nutrient content. In diet A, part of the limestone was replaced with di-calcium phosphate to increase the content of available phosphorus (P). Diet B was fed without or with supplementation with phytase (500 FTU/kg; diet BP), xylanase (4000 XU/kg; diet BX) and phytase + xylanase (500 FTU and 4000 XU/kg; diet BPX). There were no differences (P > 0.05) between diets in the ileal or total tract digestibility of organic matter (OM), NDF and crude protein (CP). The ileal and total tract digestibility for P and Ca differed (P < 0.05) between diets, while there were no treatment effects for Zn. The ileal and total tract digestibility for P and Ca was higher (P < 0.05) on diets BP and BPX than on the other diets. In conclusion, phytase improved the utilization of dietary P and Ca in a wheat-based diet, while xylanase had no additional benefits in terms of OM and CP digestibility or mineral utilization. Phytase had no effect on the digestibility of OM, CP or NDF.     

黑曲霉产木聚糖酶稳定性的研究

研究了无机离子、pH值、温度对黑曲霉(Aspergillus niger)产木聚糖酶稳定性的影响。试验结果表明：不同种类、不同浓度的无机离子对木聚糖酶活性表现出程度不同的激活或抑制作用;黑曲霉产木聚糖酶活性对pH值不敏感;温度对黑曲霉产木聚糖酶活性有显著影响。     

白灵菇产木聚糖酶营养条件的优化

以白灵菇为出发菌株,研究该菌株在不同碳源、氮源、无机盐的条件下产木聚糖酶活力大小,从中筛选出最佳培养基配方。通过测量菌丝干重,采用DNS法测定白灵菇产木聚糖酶活性大小,并根据碳源、氮源、无机盐对白灵菇产木聚糖酶的活性的影响,得出白灵菇最适培养基组成为：甘蔗渣5%、黄豆粉2%、MgSO40.15%、KH2PO40.3%、ZnSO40.01%、VB12粒。发酵液酶活力可达到60.50U/ml。     

Dietary xylanase and live yeast supplementation influence intestinal bacterial populations and growth performance of piglets fed a sorghum-based diet

This study was to evaluate the effect of xylanase supplementation and the addition of live yeast, Saccharomyces cerevisiae, on growth performance and intestinal microbiota in piglets. One hundred and eighty commercial crossbred 23-d-old piglets (PIC 417) were sorted by initial BW and allocated to 3 treatments: control (CTR) diet, CTR diet supplemented with xylanase at 16,000 birch xylan units/kg (XYL) and XYL diet supplemented with live yeast (2 × 10¹⁰ CFU/g) at 1 kg/t (XYL + LY). Each treatment had 10 replicates, with 6 animals each. A sorghum-based diet and water were available ad libitum for 42 d of the study. Average daily gain (ADG) and average daily feed intake (ADFI) were measured from 0 to 42 d (23- to 65-d-old) and feed conversion ratio (FCR) calculated. At the end of the study, bacterial identification through 16S rRNA (V3 to V4) sequencing of the ileal and caecal digesta from one piglet per replicate was performed. No treatment effects were observed on ADFI. Pigs offered the live yeast in addition to the xylanase had increased ADG compared with those supplemented with xylanase alone (XYL + LY vs. XYL; P = 0.655). FCR was improved with XYL and XYL + LY compared with CTR (P = 0.018). Clostridiaceae counts in the ileum tended to reduce by 10% with XYL and 14% with XYL + LY compared to CTR (P = 0.07). XYL and XYL + LY increased the counts of Lactobacillaceae in the caecum compared with CTR (P < 0.0001). Dietary supplementation of live yeast combined with xylanase improved growth performance and microbial balance of piglets during the nursery phase.