木聚糖酶对不同木聚糖含量的仔猪饲粮养分消化率的影响

试验设计3个消化试验分别研究在3个饲粮木聚糖水平下添加不同剂量的木聚糖酶对养分表观消化率的影响。饲粮木聚糖水平分别为5.33%、6.47%和8.44%。每个消化试验(即每个木聚糖水平下)设5个处理,分别饲喂不添加酶的基础饲粮和添加4个木聚糖酶水平的饲粮。随着饲粮木聚糖含量的提高,木聚糖酶的添加量相应增加。结果表明:当饲粮木聚糖含量低于6.47%时,添加木聚糖酶对养分消化率没有改进作用,而当木聚糖含量高达8.44%时,木聚糖酶的添加对养分消化率有一定的改进效果。与不加酶组比,加酶组粗蛋白、有机物、钙、磷、酸性洗涤纤维和能量的平均消化率分别提高了2.92%、1.05%、5.80%、5.15%、2.36%和0.84%。     

不同木聚糖水平饲粮中添加木聚糖酶对断奶仔猪生长性能及肠道微生态环境的影响

本试验旨在研究不同木聚糖水平饲粮中添加木聚糖酶对断奶仔猪生长性能、肠道微生物代谢产物和菌群数量的影响.选择30头体重相近,遗传背景相似的28日龄“杜×长×大”三元杂交断奶阉公猪,采用2×3因子试验设计,设2个饲粮木聚糖酶添加量(0和1 000 U/kg)和3个饲粮木聚糖水平(4.58％、6.23％和7.54％),将仔猪...     

小麦基础饲粮中添加木聚糖酶对生长猪生长性能、血清生化指标及肠道微生物菌群的影响

本试验旨在研究在小麦基础饲粮中添加木聚糖酶对生长猪生长性能、营养物质表观消化率、血清生化指标及肠道微生物菌群的影响,探讨适宜的木聚糖酶添加水平。选择80头健康、平均体重40 kg的"杜×长×大"生长猪,随机分为5个处理,每个处理4个重复,每个重复4头猪。正对照组饲喂玉米-豆粕型基础饲粮,负对照组饲喂小麦-豆粕型基础饲粮,木聚糖酶组分别饲喂在负对照基础饲粮上添加500、1 000和2 000 U/kg木聚糖酶的试验饲粮。试验期28 d。结果表明:1)小麦基础饲粮中添加木聚糖酶可极显著提高生长猪平均日增重(P<0.01),显著或极显著提高平均日采食量和营养物质表观消化率(P<0.05或P<0.01),其中2 000 U/kg木聚糖酶组效果最好,平均日增重和平均日采食量分别提高了26.0%和16.5%(P<0.01);2)小麦基础饲粮中添加木聚糖酶显著或极显著提高了生长猪血清葡萄糖、三碘甲腺原氨酸、四碘甲腺原氨酸和D-木糖含量(P<0.05或P<0.01),极显著降低血清尿素氮含量(P<0.01);3)饲粮组成和木聚糖酶可显著影响猪肠道微生物菌群,添加木聚糖酶可维持动物肠道微生物菌群的平衡,2 000 U/kg木聚糖酶组肠道菌群结构和玉米-豆粕饲粮饲喂条件下接近。由此可见,添加2 000 U/kg的木聚糖酶可显著改善饲喂小麦基础饲粮生长猪的生长性能和营养物质表观消化率,维持肠道微生物菌群的平衡。在木聚糖含量为11.2%的生长猪小麦基础饲粮中,木聚糖酶的适宜添加水平为2 000 U/kg。     

饲粮添加硬脂酰乳酸钠对断奶仔猪生长性能、血清生化指标及养分表观消化率的影响

本试验旨在研究硬脂酰乳酸钠(SSL)对断奶仔猪生长性能、血清生化指标及养分表观消化率的影响。试验选择25日龄的断奶仔猪336头,按体重随机分为6组,每组7个重复,每个重复8头猪。各组仔猪饲粮中SSL添加水平分别为0(对照)、250、500、750、1 000和2 000 mg/kg,试验分2个阶段,每阶段21 d。试验测定仔猪生长性能,谷丙转氨酶、谷草转氨酶、总胆固醇等血清生化指标及能量、干物质、氮和粗脂肪表观消化率。结果表明:与对照组相比,1)饲粮中添加500、750和1 000 mg/kg SSL能显著降低仔猪第2阶段料重比(P0.05),添加1000 mg/kg SSL显著降低全期料重比(P0.05);2)饲粮中添加SSL有降低试验第42天仔猪血清谷草转氨酶、谷丙转氨酶活性,增加血清高密度蛋白胆固醇含量及高密度蛋白胆固醇/低密度蛋白胆固醇值的趋势,且当添加水平为2 000 mg/kg时差异达到显著水平(P0.05);3)饲粮中添加SSL能显著提高粗脂肪表观消化率(P0.05),并且有提高氮及能量表观消化率的趋势,当添加水平为2 000 mg/kg时差异达到显著水平(P0.05)。结果提示,饲粮添加SSL能降低仔猪料重比,提高饲料养分尤其是粗脂肪的表观消化率。     

色氨酸和诱食剂对断奶仔猪养分利用的影响

研究饲粮中添加色氨酸和诱食剂对早期断奶仔猪养分消化率和血浆尿素氮(PUN)含量的影响。选用48头(23±1)日龄断奶的初始体质量为(6.0±0.5)kg的PIC仔猪,随机分为4组(1个对照组和3个试验组),每组设4个重复,每重复3头猪,单圈饲养。对照组饲喂对照饲粮,试验1~3组分别饲喂添加0.05%色氨酸、0.02%香味剂和0.02%甜味剂的饲粮,试验期为28d。结果表明,在整个试验期内,与对照组相比,添加0.02%甜味剂能显著提高仔猪对干物质、粗蛋白质、粗脂肪、有机物和粗灰分的消化率;添加0.05%色氨酸或0.02%香味剂对断奶仔猪养分消化率的影响不显著。在饲粮中添加0.02%甜味剂或0.05%色氨酸有降低PUN含量的趋势,而添加0.02%香味剂使PUN含量显著升高。     

玉米DDGS饲粮添加木聚糖酶或β-葡聚糖酶对保育猪生产性能和养分利用率的影响

本试验开展保育猪玉米DDGS饲粮添加木聚糖酶和β-葡聚糖酶对生产性能和养分消化的影响研究。135只(起始体重7.2±0.2kg)保育猪随机分成5个处理组,每个处理组6个重复,每个重复4~5只,分别为正对照组(PC,玉米/豆粕+0%玉米DDGS)、负对照组(NC,以30%玉米DDGS替代部分玉米和豆粕,不添加酶制剂)、在负对照组基础上分别添加4000 U/kg木聚糖酶(XYL)、450 U/kgβ-葡聚糖酶(BGL)或4000 U/kg木聚糖酶+450 U/kgβ-葡聚糖酶(XB)的3个酶制剂组。试猪统一饲喂玉米豆粕型饲粮1周(阶段一)后过渡到试验饲粮,试验饲粮分两阶段(阶段二:7-21天和阶段三:21-35天),试验饲粮配制以总赖氨酸含量一致为基础,营养水平达到或超过NRC(1998),为了突出纤维降解酶的作用效果,阶段二与阶段三NC、XYL、BGL和XB四组试验饲粮的代谢能比PC组分别降低3.0%和4.7%。试验发现,NC组试猪生长速度显著低于PC组(P0.001)。阶段三,BGL组与XB组试猪日增重比NC组分别提高7.7%和9.3%(P0.001);试验全期,XB组试猪比NC猪日增重提高6.6%(P0.001)。XYL与XB组干物质消化率比NC组分别提高1.6%和1.4%(P0.001),添加酶制剂组能量消化率比NC组提高5.5%(P0.001),同时,与NC组比较,酶制剂组饲粮粗蛋白质消化率提高5.9%,差异极显著(P0.001)。XYL、BGL和XB三组与NC组相比,饲粮中性洗涤纤维、酸性洗涤纤维及半纤维素消化率分别提高33%、30%与34%(P0.02)。同时,酶制剂添加组饲粮P消化率比NC组提高46%(P0.01)。结果表明,玉米DDGS饲粮联合添加木聚糖酶和β-葡聚糖酶可以提高保育猪日增重,且β-葡聚糖酶起主导作用。虽然木聚糖酶和β-葡聚糖酶对保育猪日均采食量与增重耗料比没有影响,但至少部分降低了玉米DDGS对饲粮养分利用率及生产的负面影响。     

体内法和体外法评估辽东栎籽实在生长猪饲粮中的营养价值

本试验旨在采用体内法和体外法评估辽东栎籽实(QLS)在生长猪饲粮中的营养价值。试验共由3个试验组成:试验1测定基础饲粮添加10%和20%QLS对生长猪饲粮养分消化率的影响,并采用套算法计算QLS在猪上的消化能值;试验2采用单胃动物仿生消化系统(SDS-Ⅲ),测定饲粮添加2%、6%和10%QLS对猪饲粮养分消化率的影响;试验3选择在6%QLS饲粮(对照组)基础上分别添加6 mg/kg单宁酶(100 000 U/g)、500 mg/kg非淀粉多糖酶(包含10 000 U/g的木聚糖酶、250 U/g的纤维素酶、1 000 U/g的β-葡聚糖酶、1 000 U/g的酸性甘露聚糖酶和500 U/g的果胶酶)以及单宁酶和非淀粉多糖酶组合的外源酶制剂,测定其对含QLS的猪饲粮养分消化率的影响。结果表明:1)试验1、试验2中饲粮总能、粗蛋白质和干物质的全肠道表观消化率(ATTP)均随QLS添加水平的提高而显著降低(P0.05)。2) 0、10%和20%QLS饲粮的消化能分别为(14.41±0.26) MJ/kg DM、(13.64±0.59) MJ/kg DM和(12.73±0.45) MJ/kg DM,以套算法计算得到QLS消化能约为6.36 MJ/kg DM。3)与对照组相比,各外源酶制剂添加组总磷的ATTP显著提高(P0.05),总能和粗纤维的ATTP有提高趋势(0.05≤P0.10),干物质、粗蛋白质和钙的ATTP无显著差异(P0.05)。综上所述,饲粮添加2%～10%QLS对生长猪饲粮养分的体外消化率有降低作用,添加单宁酶和非淀粉多糖酶对QLS饲粮的养分消化率无显著改善作用。     

复合甘氨酸微量元素饲喂断奶仔猪的效果试验

试验探讨新型复合甘氨酸微量元素预混料替代常规饲粮用量无机微量元素预混料对断奶仔猪生长性能、饲粮养分消化率、机体健康状况和粪中微量元素排放量等方面的影响。选择144头平均体质量7.3 kg左右的(杜×长×大)断奶仔猪,随机分为3组,每组3个重复,每重复16头,公母各半。分别饲喂常规无机微量元素饲粮(对照组)、复合甘氨酸微量元素替代低水平无机微量元素饲粮(试验1组)和低水平无机微量元素饲粮(试验2组),为期28 d。结果表明:仔猪饲粮中使用较低水平甘氨酸微量元素替代常规用量无机微量元素,能一定程度上改善仔猪的生长性能、饲料养分消化率和机体健康状况;降低饲粮中无机微量元素的添加量,可改善仔猪皮毛外观,减少粪中微量元素排放含量,提高饲料养分的消化率。     

木聚糖酶对仔猪生长性能的影响

选用杜×长×大三元杂交仔猪60头,随机分成2组,分别为对照组和试验组,在试验组仔猪饲料中添加木聚糖酶,其日增重和饲料转化率分别比对照组提高了23.32%和7.25%,差异显著(P<0.05),试验组仔猪腹泻发病率比对照组降低了10%。结果表明,在日粮中添加木聚糖酶可提高日粮中养分的消化率,降低仔猪腹泻发病率,对仔猪的生长性能具有明显的改善作用。     

低能日粮添加木聚糖酶或复合酶对肉鸡生产性能和养分消化率的影响

试验旨在研究肉鸡低能日粮中添加木聚糖酶或复合酶对肉鸡生产性能和养分消化率的影响。采用单因子的试验设计,试验分6个处理,每个处理8个重复,每重复10只肉仔鸡。6个试验饲粮处理分别为正对照组(PC)、负对照组(NC,在正对照组基础上降低表观代谢能836 kJ/kg)、以及4个在NC基础上的加酶组(分别为处理1:木聚糖酶添加量为4 000 U/kg饲料;处理2:木聚糖酶、α-淀粉酶和蛋白酶分别为300 U/kg、400 U/kg和4 000 U/kg饲料;处理3:木聚糖酶、α-淀粉酶和蛋白酶分别为:1383U/kg6、7U/kg和667U/kg;处理4:木聚糖酶、α-淀粉酶和蛋白酶分别为2 766 U/kg、134 U/kg和1 334 U/kg)。试验结果表明,与PC相比,NC降低了肉鸡的增重、提高了料肉比(P<0.05);与NC相比,4个加酶组提高增重3%~10%和改善料肉比2%~8%(P<0.05),加酶后NC组肉鸡的生产性能达到了PC水平。NC降低了干物质、粗蛋白和能量的表观消化率(P<0.05),加酶组对养分消化率具有提高作用,且达到了PC水平;木聚糖酶和复合酶两种酶制剂对肉鸡生产性能和养分消化率的影响差异不显著,处理3和4两组间差异不显著(P>0.05)。结果表明,在降低代谢能836 kJ/kg的肉鸡饲粮中添加木聚糖酶或复合酶,能够使肉鸡的生产性能和养分消化率得以补偿,低能负对照饲粮加酶后能够使肉鸡的生产性能达到与正对照组相同水平。     

Effects of xylanase supplementation on the apparent digestibility and digestible content of energy, amino acids, phosphorus, and calcium in wheat and wheat by-products from dry milling fed to grower pigs

Wheat by-products are feedstuffs that vary in nutritional value, partly because of arabinoxylans that limit nutrient digestibility. Millrun is a byproduct from dry milling wheat into flour and contains varying amounts of the bran, middlings, screening, and shorts fractions. The digestible nutrient content of mill-run is not well known. Effects of xylanase supplementation (0 or 4,000 units/kg of diet) on energy, AA, P, and Ca digestibilities were studied in a wheat control diet and 5 diets containing 30% of a by-product (mill-run, middlings, shorts, screening, or bran) in a 2 x 6 factorial arrangement of treatments. The wheat control diet was formulated to contain 3.34 Mcal of DE/kg and 3.0 g of standardized ileal digestible Lys/Mcal of DE. Diets contained 0.4% chromic oxide. Each of 12 ileal-cannulated pigs (32.5 +/- 2.5 kg) was fed 6 or 7 of 12 diets at 3 times the DE requirement for maintenance in successive 10-d periods for 6 or 7 observations per diet. Feces and ileal digesta were each collected for 2 d. Xylanase tended to increase (P < 0.10) ileal energy digestibility by 2.2 percentage units and the DE content by 0.10 Mcal/kg of DM and increased (P < 0.05) ileal DM digestibility by 2.8 percentage units; a diet x xylanase interaction was not observed. Xylanase increased (P < 0.05) total tract energy and DM digestibilities and the DE content. A diet x xylanase interaction was observed; xylanase increased (P < 0.05) total tract energy digestibility of the millrun diet from 72.1 to 78.9%, DE content from 3.19 to 3.51 Mcal/kg of DM, and DM digestibility from 71.5 to 78.6%. Diet affected (P < 0.05) and xylanase improved (P < 0.05) digestibility and digestible contents of some AA in diets and by-products, including Lys, Thr, and Val. Xylanase increased (P < 0.05) Lys digestibility by 13.8, 5.0, 5.2, 6.0, and 14.1 percentage units in millrun, middlings, shorts, screening, and bran, respectively. Diet affected (P < 0.01) total tract P and Ca digestibilities. Xylanase increased (P < 0.05) digestible P and Ca contents. In summary, nutrient digestibility varies among wheat by-products. Millrun contained 2.65 Mcal of DE/kg of DM, which xylanase increased to 3.56 Mcal of DE/kg of DM. Xylanase improved nutrient digestibility and DE content in wheat by-products; and the extent of improvement depended on the by-product. Xylanase supplementation may maximize opportunities to include wheat byproducts in swine diets and ameliorate reductions in nutrient digestibility that may be associated with arabinoxylans.     

Effects of dietary fat type, pentosan level and xylanase supplementation on digestibility of nutrients and metabolizability of energy in male broilers.

A complete two by two by four factorial design was used to examine the main effects of dietary fat type (10% soya oil or 10% beef tallow), xylanase supplementation (with or without Avizyme 1300 at 1 g/kg diet) and pentosan level (7.7 g/kg, 11.0 g/kg, 14.3 g/kg and 17.6 g/kg soluble pentosans, respectively, by varying wheat/rye proportions) as well as their interactions on intestinal chyme conditions, nutrient digestibility and nutrient utilization in male broilers. Nutrient digestibilities for the total digestive tract and at various sites of small intestine were measured during the period from day 18 to 20 of age and at day 21 of age, respectively, using a marker technique. Jejunal and ileal supernatant viscosity increased in an exponential manner as dietary pentosan concentration was increased. This increase was more pronounced in tallow fed birds but was also found in enzyme treated groups albeit at a much lower level. Xylanase activity was still detectable in the ileum of birds fed enzyme supplemented diets but its activity was found to decrease as dietary pentosan content increased. Digestibility of crude protein and that of some amino acids at the terminal ileum was decreased as dietary pentosan content was increased and significantly improved by xylanase addition. No fat effect and no interactions were detected at this site. In contrast, measurements made over the whole gastrointestinal tract showed significantly lower protein and amino acid digestibility values for tallow fed birds, and significant higher enzyme effects especially in diets with higher pentosan concentrations. Nitrogen-corrected apparent metabolizable energy (AMEN) content and net protein utilization decreased with increasing dietary pentosan content and were significantly improved by xylanase addition and were lower in tallow fed birds. Again, xylanase effects were found to be more pronounced for tallow fed birds and at higher pentosan concentrations.     

Nutrient digestibility and performance responses of growing pigs fed phytase- and xylanase-supplemented wheat-based diets

Three experiments were conducted to evaluate the effect of supplementing phytase and xylanase on nutrient digestibility and performance of growing pigs fed wheat-based diets. In Exp. 1, 10 diets were fed to 60 pigs from 20 to 60 kg of BW to determine the effect of combining phytase and xylanase on apparent total tract digestibility (ATTD) of nutrients and growth performance. The 10 diets included a positive control diet (PC; 0.23% available P; 0.60% Ca) and a negative control diet (NC; 0.16% available P; 0.50% Ca) supplemented with phytase at 0, 250, and 500 fytase units (FTU)/kg and xylanase at 0, 2,000, and 4,000 xylanase units (XU)/kg in a 3 x 3 factorial arrangement. In Exp. 2, 6 ileally cannulated barrows (initial BW = 35.1 kg) were fed 4 wheat-based diets in a 4 x 4 Latin square design, with 2 added columns to determine the effect of combining phytase and xylanase on apparent ileal digestibility (AID) of nutrients. The 4 diets were NC (same as that used in Exp. 1) or NC supplemented with phytase at 500 FTU/kg, xylanase at 4,000 XU/kg, or phytase at 500 FTU/kg plus xylanase at 4,000 XU/kg. In Exp. 3, 36 barrows (initial BW = 55.5 kg) were fed 4 diets based on prepelleted (at 80 degrees C) and crumpled wheat for 2 wk to determine the effect of phytase supplementation on ATTD of nutrients. The 4 diets fed were a PC (0.22% available P; 0.54% Ca) and a NC (0.13% available P; 0.43% Ca) alone or with phytase at 500 or 1,000 FTU/kg. All diets in the 3 experiments contained Cr(2)O(3) as an indigestible marker. No synergistic interactions were detected between phytase and xylanase on any of the response criteria measured in Exp. 1 or 2. There were no dietary effects on growth performance in Exp. 1. In Exp. 1, phytase at 250 FTU/kg increased the ATTD of P and Ca by 51 and 11% at 20 kg of BW or by 54 and 10% at 60 kg of BW, respectively, but increasing the level of phytase to 500 FTU/kg only increased (P < 0.05) ATTD of P at 20 kg of BW. In Exp. 2, phytase at 500 FTU/kg increased (P < 0.05) the AID of P and Ca by 21 and 12%, respectively. In Exp. 3, phytase at 500 FTU/kg improved (P < 0.05) ATTD of P by 36%, but had no further effect at 1,000 FTU/kg. Xylanase at 4,000 XU/kg improved (P < 0.05) AID of Lys, Leu, Phe, Thr, Gly, and Ser in Exp. 2. In conclusion, phytase and xylanase improved P and AA digestibilities, respectively, but no interaction between the 2 enzymes was noted.     

Supplementation of carbohydrases or phytase individually or in combination to diets for weanling and growing-finishing pigs

The overall objective of the studies reported here was to evaluate the growth and nutrient utilization responses of pigs to dietary supplementation of phytate- or nonstarch polysaccharide-degrading enzymes. In Exp. 1, growth performance and nutrient digestibility responses of forty-eight 10-kg pigs to dietary supplementation of phytase or a cocktail of xylanase, amylase, and protease (XAP) alone or in combination were evaluated. The growth response of one hundred fifty 23-kg pigs to dietary supplementation of phytase or xylanase individually or in combination was studied in Exp. 2 in a 6-wk growth trial, whereas Exp. 3 investigated the nutrient digestibility and nutrient retention responses of thirty 24-kg pigs to dietary supplementation of the same enzymes used in Exp. 2. In Exp. 1, the pigs were used in a 28-d feeding trial. They were blocked by BW and sex and allocated to 6 dietary treatments. The treatments were a positive control (PC) diet; a negative control (NC) diet marginally deficient in P and DE; NC with phytase added at 500 or 1,000 phytase units (FTU)/kg; NC with xylanase at 2,500 units (U)/kg, amylase at 400 U/kg, and protease at 4,000 U/kg; and NC with a combination of phytase added at 500 FTU/kg and XAP as above. In Exp. 2 and 3, the 5 dietary treatments were positive control (PC), negative control (NC), NC plus 500 FTU of phytase/kg, NC plus 4,000 U of xylanase/kg, and NC plus phytase and xylanase. In Exp. 1, low levels of nonphytate P and DE in the NC diet depressed (P < 0.05) ADG of the pigs by 16%, but phytase linearly increased (P < 0.05) ADG by up to 24% compared with NC. The cocktail of XAP alone had no effect on ADG of pigs, but the combination of XAP and phytase increased (P < 0.05) ADG by 17% compared with the NC treatment. There was a linear increase (P < 0.01) in Ca and P digestibility in response to phytase. In Exp. 2, ADG was 7% greater in PC than NC (P < 0.05); there were no effects of enzyme addition on any response. In Exp. 3, addition of phytase alone or in combination with xylanase improved (P < 0.05) P digestibility. Phosphorus excretion was greatest (P < 0.01) in the PC and lowest (P < 0.05) in the diet with the combination of phytase and xylanase. The combination of phytase and xylanase improved P retention (P < 0.01) above the NC diet to a level similar to the PC diet. In conclusion, a combination of phytase and carbohydrases improved ADG in 10-kg but not 23-kg pigs, but was efficient in improving P digestibility in pigs of all ages.     

Influence of method of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy, digestive tract measurements and gut morphology of broilers

1. The aim of the present study was to examine the influence of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy (AME), digesta viscosity, and digestive tract measurements of broilers fed on wheat-based diets. The influence of the method of whole wheat inclusion (pre- or post-pelleting) was also compared. A 3 x 2 factorial arrangement of treatments was used with three diet forms (648 g/kg ground wheat [GW], GW replaced by 200 g/kg of whole wheat before [WW1] or after cold-pelleting [WW2]) and two xylanase levels (0 and 1000 XU/kg diet). 2. Birds given diets containing whole wheat had improved weight gains, feed efficiency and AME compared to those fed on diets containing ground wheat. The relative gizzard weight of birds fed WW2 diets was higher than in those fed GW and WW1 diets. Pre-pelleting inclusion of whole wheat had no effect on relative gizzard weight. Post-pelleting inclusion of whole wheat resulted in greater improvements in feed efficiency and AME than the pre-pelleting treatment. 3. Xylanase supplementation significantly improved weight gain, feed efficiency and AME, irrespective of the wheat form used. Viscosity of the digesta in the duodenum, jejunum and ileum were reduced by xylanase addition. Xylanase supplementation reduced the relative weight of the pancreas. 4. Neither xylanase supplementation nor whole wheat inclusion influenced the relative weight and length of the small intestine. 5. Xylanase supplementation increased ileal villus height. A significant interaction between diet form and xylanase was observed for ileal crypt depth. Xylanase supplementation had no effect on crypt depth in birds fed on diets containing GW, but increased the crypt depth in WW2 diets. No significant effects of diet form and xylanase supplementation were observed for the thickness of the tunica muscularis layer of gizzard or villus height, crypt depth, goblet cell numbers or epithelial thickness in the ileum. 6. Improved performance observed with post-pelleting inclusion of whole wheat was associated with increased size of the gizzard and improved AME. The gizzard development hypothesis, however, will not explain the improvements observed with pre-pelleting inclusion of whole wheat, suggesting the involvement of other factors.     

Apparent precaecal digestibility of nutrients and level of endogenous nitrogen in digesta of the small intestine of growing pigs as affected by various digesta viscosities.

Sixteen male growing pigs of about 24 kg BW were fitted with both a duodenal re-entrant and a post-valve T-shaped cannula inserted in the caecum. The animals were divided into four groups. Each group received one of the following diets: corn starch-soybean protein isolate-based diet without (diet C) and with carboxymethylcellulose (diet CMC) or a rye-wheat-based diet without (diet RW) and with xylanase addition (diet RWX). The diets provided similar levels of apparent precaecal digestible crude protein (CP), lysine, methionine + cystine, threonine and tryptophan. Additionally, [15N]-yeast was given with the diets during the first 10 days of the experiment. For estimation of digesta viscosity, N-flow of dietary and endogenous origin, apparent precaecal digestibilities of dry matter (DM), CP, amino acids and non starch polysaccharides (NSP) (only in pigs fed diets RW and RWX), ileal and duodenal digesta were quantitatively collected on day 16 and 17, respectively. The endogenous N-proportion was measured by the ratio of 15N enrichment in the digesta and urine. The duodenal and ileal digesta supernatant viscosity increased as carboxymethylcellulose was included into the diet. Xylanase addition to the rye-wheat based diet reduced the viscosity in the ileal digesta. There were no differences in precaecal digestibilities of DM, CP and amino acids between diet C and CMC. The precaecal digestibilities of DM and soluble and insoluble NSP increased from 69.5% to 73.9%, from 1.3% to 47.9% and from 17.0% to 35.4%, respectively, as xylanase was added to the rye-wheat-based diet. The apparent precaecal digestibility of most essential amino acids increased by 2 to 5 percent units. The amounts of endogenous N at the duodenal level were estimated to be 158, 233, 313 and 276 mg per 12 h per kg0.75 BW of pigs fed diets C, CMC, RW and RWX, respectively. The corresponding values at the ileal level were 95, 107, 164 and 150 mg per 12 h per kg0.75 BW. For endogenous N amounts, significant differences were observed between diets C and CMC (duodenum) and also between semi-purified and cereal-based diets (duodenum and ileum). Methodological aspects for the estimation of endogenous N using the isotope dilution technique are discussed. Obviously, the digesta viscosity per se does not affect the nutrient absorption and endogenous N flow within the small intestine of pigs. Other properties of complex dietary fibre, digesta passage rate or bacterial activity probably contribute to the observed changes.     

Soybean hulls as a dietary fiber source for dogs.

In Exp. 1, soybean hull samples were obtained from nine sources across the United States and analyzed for nutrient content to determine their suitability for inclusion in dog diets. Compositional data revealed variation in both the amount of total dietary fiber (TDF; 63.8 to 81.2%) in the soybean hulls and the ratio of insoluble:soluble fiber (5.0:1 to 15.4:1). Crude protein content varied widely among sources, ranging from 9.2 to 18.7%. An in vivo trial (Exp. 2) was conducted using a premium dog diet containing 3.0, 4.5, 6.0, 7.5, or 9.0% soybean hulls (DM basis). There was a negative linear effect (P < .05) of soybean hull inclusion in the diet on DM, OM, TDF, and GE total-tract digestibilities, as well as on calculated ME. Crude protein and fat digestibilities were unaffected by treatment. Based on these results, ileally cannulated dogs were fed diets containing 6.0, 7.5, or 9.0% soybean hulls (DM basis) in addition to diets containing either 0% supplemental fiber or 7.5% beet pulp (Exp. 3). Nutrient digestion at the ileum was unaffected by inclusion of supplemental fiber. Total tract digestion of DM, OM, and GE was lower ( P < .05) for diets containing supplemental fiber when compared with the diet containing 0% fiber. Crude protein and fat digestibilities were unaffected by treatment. There was no difference in nutrient digestibility between those diets containing soybean hulls and a diet containing beet pulp. Soybean hull inclusion in the diet resulted in a negative linear effect (P < .05) on calculated ME, in addition to lowering ME (P < .05) when compared with the 0% fiber control diet. Calculated ME for dogs fed a 7.5% beet pulp-containing diet was lower (P < .05) than that for dogs fed the soybean hull-containing diets. Results indicate that soybean hulls can be an effective dietary fiber source in dog diets.     

Growth performance, gastrointestinal microbial activity, and nutrient digestibility in early-weaned pigs fed diets containing flaxseed and carbohydrase enzyme

The effects of ground flaxseed (FS) and a multicarbohydrase enzyme (C) supplement on piglet performance, gastrointestinal microbial activity, and nutrient digestibility were investigated in a 28-d trial. The enzyme supplement provided 500 units of pectinase, 50 units of cellulase, 400 units of mannanase, 1,200 units of xylanase, 450 units of glucanase, and 45 units of galactanase per kilogram of diet. Ninety-six pigs were weaned at 17 d of age (BW, 6.1 +/- 0.4 kg, mean +/- SD) and assigned to treatments based on a 2 x 2 factorial arrangement in a completely randomized design, with 6 pens per diet (4 pigs per pen). The diets contained wheat, barley, peas, soybean meal, and canola meal with 0 or 12% FS, and were fed without or with C. Flaxseed was included by changing the levels of the other ingredients to balance the diets for DE and nutrients. Diets had similar nutrient contents and met the NRC (1998) nutrient specifications, with the exception of DE, CP, and AA, which were 95, 94, and 97% of the NRC requirements, respectively. Diets were fed in a 2-phase feeding program (2 wk/phase). Feed intake and BW were measured weekly, and 1 pig per pen with a BW nearest the pen average was bled weekly to evaluate plasma urea nitrogen. On d 28, fresh fecal samples were collected from each pen and 1 pig per pen with a BW nearest the pen average was killed to evaluate intestinal microbial activity and nutrient digestibility. A dietary effect on piglet performance was observed only in wk 3, when the FS diets decreased (P = 0.005) ADG and G:F, tended to decrease (P = 0.070) ADFI, and increased (P = 0.027) plasma urea nitrogen. An interaction between FS and C was observed for ileal digesta viscosity (P = 0.045), such that C increased viscosity in the FS diet but had no effect in the non-FS diet. Flaxseed and C interacted to affect ileal ammonia content (P = 0.049), such that in the absence of FS, pigs fed the diet with C had lower ammonia than those on the diet without C. Flaxseed and C affected other ileal parameters independently. Pigs fed the FS diets had decreased (P = 0.003 to 0.033) anaerobic spore counts, organic acid, DM, CP, and nonstarch polysaccharide (NSP) digestibility compared with pigs fed the non-FS diets, whereas pigs fed the C-supplemented diets had greater (P = 0.009 to 0.061) lactobacilli counts, lactate, DM, and NSP digestibility than pigs fed the unsupplemented diets. In conclusion, FS reduced ileal microbial activity, nutrient digestibilities, and piglet performance in wk 3. The multicarbohydrase supplement increased ileal DM and NSP digestibilities as well as lactobacilli counts and lactate.