抗生素对苏淮猪发酵床养殖环境的影响

选择苏淮猪20头,按照性别相同(母猪)、体重一致(30.0±5.5)kg的原则分为4个组。对照组(CT)为健康猪不添加或注射任何药物,组1(T1)为健康猪群,采用拌料方式,用药量为预防量;组2(T2)为轻微咳嗽猪群,采用拌料方式,用药量为治疗量;组3(T3)为重症连续长咳猪群,采用拌料和肌注两种方式结合治疗。试验期30 d,分别对每组床体进行温湿度测量,及其各组床体对粪便的分解能力和圈舍气味进行评定。结果表明各项指标T1组与对照组差异不显著(P>0.05)。T2组发酵床床体中层15 cm和下层30 cm处温度显著低于对照组(P<0.05),垫料表面湿度和内部湿度均显著大于对照组(P<0.01),对粪便的分解能力显著(P<0.05)低于对照组。T3组发酵床床体表层0 cm处(P<0.05)、中层15 cm(P<0.05)和下层30 cm(P<0.01)处温度显著低于对照组,垫料表面湿度和内部湿度均显著大于对照组(P<0.01),对粪便的分解能力显著(P<0.01)低于对照组,且T3组气味显著重于对照组(P<0.01)。     

不同饲养方式及发酵床垫料环境对猪生产性能、血液生化指标及肠道消化酶活性的影响

探讨不同饲养方式及发酵床垫料环境对猪生产性能、血液生化指标及肠道消化酶活性的影响。将75头60日龄苏钟猪随机分为5组:对照组Ⅰ(水泥地饲养,自由采食)、对照组Ⅱ(水泥地饲养,顿饲)、木屑发酵床组(垫料基质为木屑,简称木屑组,自由采食)、酒糟发酵床组(垫料基质为50%酒糟+50%木屑,简称酒糟组,自由采食)、菌糠发酵床组(垫料基质为50%菌糠+50%木屑,简称菌糠组,自由采食),试验期100 d。(1)酒糟组、木屑组和菌糠组各项生产性能都显著优于对照组(P0.01、P0.05),料重比酒糟组菌糠组木屑组对照组Ⅱ对照组Ⅰ。(2)育肥中期,酒糟组血清总蛋白含量最高;酒糟组和菌糠组、木屑组血清白蛋白含量都显著高于对照组;菌糠组和酒糟组、木屑组血清球蛋白含量都显著低于对照组(P0.01、P0.05)。酒糟组猪血清谷丙转氨酶和谷草转氨酶活性显著高于其他各组(P0.05);木屑组、菌糠组、对照组Ⅱ血清碱性磷酸酶活性显著高于酒糟组(P0.05)和对照组Ⅰ(P0.01)。菌糠组、木屑组猪血清葡萄糖最高,显著高于对照组Ⅰ(P0.01)和对照组Ⅱ(P0.05),对照组Ⅱ血清葡萄糖也显著高于对照组Ⅰ(P0.05);酒糟组血清胆固醇含量最高,显著高于对照组Ⅰ(P0.01)和对照组Ⅱ(P0.05),菌糠组次之,显著高于对照组Ⅰ(P0.05);对照组猪血清甘油三酯含量显著高于发酵床各组(P0.01)。(3)育肥后期,各组猪血清总蛋白、球蛋白含量,谷丙转氨酶、碱性磷酸酶活性无显著差异(P0.05);酒糟组血清白蛋白含量最高,显著高于对照组Ⅱ和木屑组(P0.05);发酵床处理组谷草转氨酶活性极显著低于对照组(P0.01);菌糠组猪血清葡萄糖水平最高,显著高于对照组Ⅰ(P0.01)和木屑组(P0.05),酒糟组、对照组Ⅱ血糖浓度次之,显著高于对照组Ⅰ(P0.05);对照组Ⅱ猪血清甘油三酯含量最高,极显著高于其他各组(P0.01)。(4)发酵床处理组猪十二指肠胰蛋白酶、脂肪酶活性显著高于对照组(P0.05),其中,活性高低依次为菌糠组酒糟组木屑组对照组Ⅱ对照组Ⅰ。采取发酵床饲养方式,特别是酒糟、菌糠替代木屑作为垫料的发酵床环境,较传统水泥地面和木屑发酵床饲养环境更有利于猪的健康生长。     

不同处理方式对发酵床模式下猪主要寄生虫病防治效果

探讨发酵床养猪模式下寄生虫病防控效果,构建寄生虫病防控规程。将发生寄生虫病的表层垫料混匀,添加4组发酵床表层,将60头35日龄苏钟猪随机分为4组:A组(垫料翻耙后进猪,定期药物驱虫2次)、B组(垫料堆积发酵后进猪)、C组(垫料发酵后进猪,定期药物驱虫2次)、D组(垫料翻耙后进猪,感染寄生虫时药物治疗1次),试验期120 d。垫料堆积发酵组垫料发酵温度极显著高于垫料翻耙组(P0.01),并且堆积发酵后垫料中未检出寄生虫卵,试验第45、90天在垫料和粪便中的蛔虫卵、鞭虫卵、球虫卵数量均处于低水平;采用药物驱虫程序可有效降低猪粪便中的蛔虫卵、鞭虫卵、球虫卵数量和对应寄生虫的感染率,但不能避免垫料中寄生虫的重复感染; B、C组末重、总增重、平均日增重均显著高于A组(P0.05)和D组(P0.01),A组末重、总增重、平均日增重也均显著高于D组(P0.05)。综上所述,在发酵床养猪模式下,采用进猪前药物驱虫、垫料堆积发酵,猪群饲养阶段定期驱虫,同时注意养殖管理器具消毒,可有效降低寄生虫感染率。     

垫料类型及饲养密度对肉鸡生长性能、组织器官重量及肉品质的影响

本研究旨在评估垫料类型及饲养密度对肉鸡生长性能、组织器官相对重量及肉品质的影响。试验将560只1日龄商品肉仔鸡随机分为4组，每组5个重复，每个重复28只。在为期6周的饲养试验中，T1和T2组肉鸡采用秸秆作为垫料，饲养密度分别为10和15只/cm2，T3和T4组肉鸡采用木屑作为垫料，饲养密度分别为10和15只/cm2。结果：垫料类型对肉鸡体重、日增重和采食量无显著影响（P＞0.05），但木屑组肉鸡的料重比显著低于秸秆组（P＜0.05）。在同一垫料类型条件下，饲养密度为10只/m2组肉鸡的平均日增重和采食量均显著高于饲养密度为15只/m2组（P＜0.05）。垫料类型和饲养密度对肉鸡日增重、采食量和料重比的影响具有显著交互作用（P＜0.05）。无论饲养密度如何，秸秆垫料组肉鸡的腹脂相对重量均显著高于木屑垫料组（P＜0.05），而秸秆作为垫料组的肌肉滴水损失和温度均显著高于木屑组（P＜0.05）。在同一垫料类型条件下，高密度组肌肉蒸煮损失显著低于低密度组（P＜0.05）。结论：使用木屑作为地面平养肉鸡的垫料，饲养密度为10只/m2时可改善肉鸡增重和饲料效率，降低腹脂相对重量，对肉品质无负面影响。 [关键词]垫料|饲养密度|肉鸡|生长性能|组织器官重量|肉品质     

北方冬季生物发酵床垫料理化性质及温度分布特征研究

为指导发酵床垫料的日常管理工作,提高冬季寒冷地区生物发酵床的运行效率。通过对我国北方冬季生物发酵床垫料的理化性质和温度分布特征研究,发现冬季采用生物发酵床技术的圈舍内的温度、湿度可以达到约12℃和82%,均高于普通漏缝地板猪舍内的约10℃和68%。发酵床休息区垫料pH、电导率(EC)和含水率分别为约8.00、2.40 mS/cm和45%,均低于粪尿区垫料的约8.50、4.70mS/cm和64%,而发酵床休息区垫料的持水性约为3.50倍,高于粪尿区垫料的约2.15倍,另外,休息区垫料重金属和有机质含量方面均低于粪尿区,且休息区各个深度垫料的平均温度约高于粪尿区5℃,表明发酵床休息区垫料的理化性质优于粪尿区。发酵床垫料的纵向温度分布特征为:随着垫料深度增加,温度先升高后降低,在深度为20cm和30cm处最高,比其他深度高5~10℃,可判定核心发酵层位于离表面下20~30cm深度处。与未添加功能菌剂的发酵床(CK组)相比,按比例300g/m3添加功能菌剂的生物发酵床(BFB组)的垫料平均温度要高出2℃左右,且温度分布也更为均匀,应用双因素方差分析对功能区和功能菌剂的影响效果进行分析后发现,不同功能区对发酵床垫料的理化性质和温度的影响效果更为显著。因此,在北方冬季的生物发酵床的日常管理中,可以适当添加一定比例的功能菌剂,尤其需要及时对粪区粪便进行疏解,并对垫料的翻动深度应该保证不低于30cm,及时进行圈舍的除湿工作。     

屎肠球菌T013复合制剂饲喂生长猪的效果研究

试验旨在研究日粮中添加屎肠球菌T013复合制剂对生长猪的生产性能、粪便微生物、环境指标及血清指标的影响。选用体重在(31.75±3.78)kg的杜×长×大三元杂交仔猪120头,随机分成对照组(基础日粮)、试验Ⅰ组(基础日粮中添加3%屎肠球菌T013复合制剂)和试验Ⅱ组(基础日粮中添加6%屎肠球菌T013复合制剂),每组4个重复,每个重复10头猪,试验期为28 d。结果表明,屎肠球菌T013复合制剂能增加生长猪日采食量和日增重,降低料重比,但差异不显著(P＞0.05),并且能显著减少腹泻率(P＜0.05);试验Ⅱ组能够极显著降低粪便pH和减少大肠杆菌数量,增加乳酸菌数量(P＜0.01);试验组均能够极显著的减少NH₃的排放(P＜0.01);试验Ⅱ组能够显著增加血清IgG含量和减少尿素氮含量(P＜0.05),对总蛋白、白蛋白、白蛋白/球蛋白和葡萄糖的含量无显著影响(P＞0.05)。因此,屎肠球菌T013复合制剂能够降低生长猪的腹泻率,改善肠道微生态环境,减少NH₃ 的排放,增强猪的免疫能力。     

植物乳杆菌GF103对生长猪生长性能、营养物质消化率及粪便微生物数量的影响

本试验旨在研究植物乳杆菌(Lactobacillus plantarum)GF103对生长猪生长性能、营养物质消化率及粪便微生物数量的影响。利用随机区组试验设计方法,将平均体重(26.36±1.93)kg的300头生长猪分为5个组,每组3个重复,每重复20头,重复内生长猪日龄一致、公母各占1/2。对照(CON)组饲喂基础饲粮,抗生素(PC)组在基础饲粮中添加杆菌肽锌40 mg/kg,植物乳杆菌1~3(T1、T2和T3)组分别在基础饲粮中添加1×109、5×109、1×1010CFU/kg的植物乳杆菌GF103。试验预试期7 d,正试期30 d。结果表明:1)T1组生长猪平均日增重和平均日采食量均显著高于其他各组(P0.05),料重比则显著低于其他各组(P0.05)。T2和T3组生长猪的平均日增重、平均日采食量和料重比与PC和CON组相比差异均不显著(P0.05)。各组间生长猪腹泻率无显著差异(P0.05)。2)T1、T3及CON组的总能、干物质、有机物质、粗蛋白质、粗脂肪消化率显著高于PC和T2组(P0.05),各组之间的中性洗涤纤维和磷的消化率无显著差异(P0.05)。3!T1、T2和T3组生长猪粪便中乳酸菌数量显著高于CON和PC组(P0.05),并且粪便乳酸菌数量随着植物乳杆菌GF103添加剂量的增加而增加;各组生长猪粪便大肠杆菌数量无显著差异(P0.05);T1组生长猪粪便中乳酸菌/大肠杆菌与T3组无显著差异(P0.05),显著高于其他各组(P0.05)。结果提示,在生长猪饲粮中添加1×109CFU/kg植物乳杆菌GF103,能够改善生长猪肠道菌群环境,提高生长猪生长速度和饲料利用效率。     

日粮中添加发酵苹果渣对育肥猪生产性能和血清生化指标的影响

试验研究日粮中添加发酵苹果渣对育肥猪生产性能和血清指标的影响。100头育肥猪随机分成5组,每组20头。对照组育肥猪饲喂基础日粮,试验1、2、3、4组育肥猪饲喂添加5%、8%、10%、15%发酵苹果渣的基础日粮,试验期60 d。结果显示,试验组育肥猪平均日增重极显著高于对照组(P0.01),料重比极显著低于对照组(P0.01),试验3组育肥猪组料重比极显著低于其他各组(P0.01)。试验组育肥猪血清中的甲状腺素(T4)、免疫球蛋白G (IgG)水平极显著高于对照组(P0.01);试验组育肥猪血清中白蛋白、葡萄糖和总胆固醇含量略有上升,而甘油三酯降低(P0.05)。研究表明,基础日粮添加10%发酵苹果渣能提高育肥猪的生产性能。     

发酵床奶牛舍垫料理化性状和霉菌毒素的季节与方位变化

该文旨在研究发酵床饲养模式奶牛垫床垫料的理化和霉菌毒素指标的季节变化与方位差异。试验采集某发酵床奶牛舍不同季节和不同方位的垫床垫料,并进行理化指标和霉菌毒素的测定。结果表明:秋(554.14 g)冬(516.26 g)季节垫料的容重显著高于春夏季节(P0.05);春(36.67 cm)夏(37.50 cm)垫床的深度显著高于秋冬(P0.05);但垫料的pH(7.11～7.40)在季节间和方位间皆无显著差异(P0.05);夏季垫料的含水量(48.06%)显著低于其他3个季节(P0.05);春季垫料的碳含量显著高于其他3个季节(P0.05);秋季垫料的氮含量显著高于其他3个季节(P0.05),计算碳氮比在37.99～53.31:1范围变化;但磷含量在季节间和方位间皆无显著差异(P0.05)。另外,霉菌毒素中黄曲霉毒素B_1、呕吐毒素、赭曲霉毒素等在季节间和方位间均无显著差异(P0.05);但冬季的赤霉烯酮含量显著高于春季与秋季(P0.05)。综上,该发酵床奶牛舍垫床垫料的pH为7.11～7.40、含水率为48.06%～62.32%、碳氮比为37.99～53.31:1,且霉菌毒素的含量较低,适合于奶牛养殖排泄物的发酵降解。     

不同深度垫料对养猪土著微生物发酵床稳定期微生物菌群的影响

通过对养猪土著微生物发酵床稳定期时核心发酵层的判断以及对该发酵床土著微生物的分布进行分析,旨在探讨不同深度垫料对养猪土著微生物发酵床稳定期微生物菌群的影响。试验分别从发酵床的表层和深30、40、50、70cm处取垫料样品后测其温度、pH值、自由水、硝态氮和粗纤维,并从中分离纯化出22株菌,采用16SrDNA序列分析鉴定微生物种类。结果表明,表层垫料温度显著小于其他4层（P〈0.05）,并且随着深度加深垫料温度依次降低;表层垫料pH值显著高于其他4层（P〈0.05）,其中30、40cm处垫料pH值相等,50、70cm处垫料pH值相等,40、50cm处垫料差异显著,整体呈下降趋势;表层垫料自由水、硝态氮和粗纤维含量与30cm处垫料含量差异不显著,从整体上看,30、40、50、70cm深垫料的自由水和硝态氮含量呈下降趋势,而粗纤维含量呈上升趋势;表层活菌数显著（P〈0.05）小于30cm深处垫料活菌数,30、40、50、70cm深垫料的活菌数依次降低。结果表明,30cm深处为该发酵床的核心发酵层,地衣芽孢杆菌为该发酵床的主要土著菌种。表层垫料的各项指标受环境影响较大,其所存在的菌种主要为大肠埃希菌属。40cm深处所分离的菌种主要为乙酰微小杆菌。50、70cm深处除分离出地衣芽孢杆菌外还分离出其他多种微生物。稳定期土著微生物发酵床各层的菌种分布主要与外界环境的变化有关。     

清洁型复合饲料添加剂对发酵床育肥前期猪生长、营养代谢及激素分泌的影响

选取健康无病、体重30kg左右的苏钟猪120头,随机分为2组,研究发酵床育肥前期猪日粮中应用清洁型复合饲料添加剂对猪生长性能、营养物质代谢及激素分泌的影响。结果表明：（1）清洁饲粮组体重、平均日增重和料重比较对照组无显著差异（P〉0.05）。（2）清洁型复合饲料添加剂组血清总蛋白及白蛋白较对照组均有提高,但差异不显著（P〉0.05）;甘油三酯含量较对照组降低了58.82%（P〈0.01）,而葡萄糖、胆固醇、高密度胆固醇及低密度胆固醇差异不显著（P〉0.05）;清洁型复合饲料添加剂对血清中酶活性的变化无显著性影响,但谷丙转氨酶及谷草转氨酶都有提高的趋势（P〉0.05）。（3）清洁饲粮组血清中T3和T4含量均显著提高,其中T3和T4含量分别较对照组提高了18.12%和18.84%（P〈0.05）,IGF-Ⅰ、INS和GH含量较对照组也有提高的趋势,但差异不显著（P〉0.05）。以上结果表明,在发酵床育肥前期猪日粮中应用清洁型复合饲料添加剂,可提高猪的生长性能,改善营养物质代谢水平,降低血清中甘油三酯的含量,并提高猪血清中T3、T4的含量,改善猪体内内分泌激素的水平。     

Estimation of the ideal ratio of true ileal digestible sulfur amino acids:lysine in 8- to 26-kg nursery pigs

Four experiments were conducted to determine the ideal ratio of true ileal digestible (TID) sulfur AA to Lys (SAA:LYS) in nursery pigs at two different BW ranges using both DL-Met and 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) as Met sources. In Exp. 1, 1,549 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 8.3 +/- 0.08 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a semicomplex corn-soybean meal-based diet (1.32% TID Lys) with no supplemental HMTBA or DL-Met (47.7% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (52.7, 57.7, 62.7, and 67.7% TID SAA:LYS). In Exp. 2, 330 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 11.4 +/- 0.10 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.15% TID Lys) with no supplemental HMTBA or DL-Met (49% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (54, 59, 64, and 69% TID SAA:LYS). In Exp. 3, 1,544 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 12.4 +/- 0.13 kg) were allotted to one of nine dietary treatments as in Exp. 2. In Exp. 4, 343 nursery pigs (Genetiporc; initial BW 12.8 +/- 0.56 kg) were allotted to one of six dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.05% TID Lys) with no supplemental DL-Met (49% TID SAA:LYS). Diets 2 to 5 consisted of the basal diet supplemented with four levels of DL-Met (54, 59, 64, and 69% TID SAA:LYS), and Diet 6 was the basal diet supplemented with one equimolar level of HMTBA to satisfy 59% TID SAA:LYS ratio. In all experiments, increasing the TID SAA:LYS ratio resulted in quadratic improvements in ADG (P < or = 0.09) and G:F (P < or = 0.05). Three different methods were used to estimate the optimal TID SAA:LYS ratio for each experiment. The two-slope broken-line regression model, x-intercept value of the broken-line and quadratic curve, and 95% of upper asymptote across the four experiments indicated that the average optimal TID SAA:LYS ratios were 59.3, 60.1, and 57.7% for ADG and 60.6, 61.7, and 60.1% for G:F, respectively. Thus, the optimal TID SAA:LYS ratio for 8- to 26-kg pigs based on the average value of these three estimates was 59.0% for ADG and 60.8% for G:F.     

Effects of dietary humic substances on pig growth performance, carcass characteristics, and ammonia emission

Five experiments were conducted to test the effects of various dietary humic substances (HS; HS1, 2, 3, and 4, each with different fulvic and humic acid contents) on pig growth, carcass characteristics, and ammonia emission from manure. In Exp. 1, 120 pigs were allotted to 3 dietary treatments without HS (control) or with HS1 at 0.5 and 1.0% (8 pens/treatment and 5 pigs/pen) and fed diets, based on a 5-phase feeding program, from weaning (d 21.3 +/- 0.3 of age) to 60 kg of BW. In Exp. 2 and 3, 384 pigs (192 for each experiment) were allotted to 3 dietary treatments without HS, with HS1, or with HS2 (0.5%) for Exp. 2 and without HS, or with HS3 or HS4 (0.5%) for Exp. 3 (8 pens/treatment and 8 pigs/pen in each experiment). Pigs were fed diets, based on a 6-phase feeding program, from weaning (25.4 +/-0.2 and 23.6 +/-0.3 d of age for Exp. 2 and 3, respectively) to 110 kg of BW. In Exp. 4, 96 pigs were weaned at 22.1 +/-0.2 d of age and allotted to 2 treatments without or with HS1 at 0.5% (6 pens/treatment and 8 pigs/pen), and in Exp. 5 96 pigs were weaned at 20.9 +/-0.3 d of age and allotted to 3 treatments without HS, or with HS3 or HS4 (0.5%; 4 pens/treatment and 8 pigs/pen). Pigs were fed the diets for at least 2 wk before they were moved to an environmental chamber to measure aerial ammonia and hydrogen sulfide for 48 h at 5-min intervals. In Exp. 1, pigs fed diets with HS1 at 0.5% had greater (P < 0.05) ADG during phase 3 and greater (P < 0.05) G:F during phases 3 and 5 than control pigs. In Exp. 2, pigs fed diets with HS1 or HS2 at 0.5% had greater (P < 0.05) ADG and G:F than control pigs during the entire feeding period, whereas in Exp. 3 HS3 or HS4 did not improve pig growth performance. Ammonia emission from manure was reduced by 18 or 16% when pigs were fed diets with HS1 (P = 0.067) or HS4 (P = 0.054), respectively. The results of this study indicate that the effects of dietary HS are variable but may improve growth performance of pigs and reduce ammonia emission from manure. Further research is needed to clarify these effects and the mechanisms by which HS may cause them.     

Effect of inorganic selenium supplementation on selenium retention in postweaning swine

A total of 64 weanling pigs was used in a randomized complete-block experiment to evaluate the efficacy of various inorganic Se levels on weekly Se balance measurements over a 5-wk post-weaning period. Four-week-old weaned pigs were fed a 20% protein, corn-soybean meal diet supplemented with 0, .3, .5 or 1.0 ppm Se from sodium selenite. Eight pigs were allotted by weight, litter and sex to each metabolism crate. A 2-d preliminary period followed by a 5-d collection period was conducted for five weekly periods. Feed intake was provided ad libitum but was similar between dietary Se levels. Fecal Se excretion increased each week and with increasing dietary Se level. Apparent digestibility of Se was relatively constant for each period when inorganic Se was fed, averaging approximately 70%, whereas it ranged between 30 to 40% for pigs fed the basal diet during wk 2 through 5. Urinary Se decreased during the postweaning periods for pigs fed the basal diet, but increased linearly as dietary Se increased during the initial 2-wk postweaning period and then quadratically during wk 3 through 5. There was a net loss of Se from the body when the Se-unsupplemented basal diet was fed during the initial 2 wk postweaning, whereupon, it became positive. Selenium retention in pigs supplemented with inorganic Se increased each week of the trial. When Se retention was expressed in relation to Se intake, the resulting regression was linear (R2 = .99), suggesting that Se retention in the postweaning pig increased in direct proportion to the amount consumed when diets contained up to 1.0 ppm Se.     

Effect of dietary Echinacea purpurea on viremia and performance in porcine reproductive and respiratory syndrome virus-infected nursery pigs

The effect of dietary Echinacea purpurea on performance, viremia, and ontogeny of the humoral antibody response against porcine reproductive and respiratory syndrome virus (PRRSV) infection was evaluated in weaned pigs. In three replicates, 120 weaned pigs (25 +/- 1 d of age; 8.46 +/- 0.48 kg of BW) from a PRRSV-naive herd were allotted randomly to one of eight pens (diets) in two separate rooms (four pens/room), with each pen containing five pigs. Pigs began one of four dietary treatments (as-fed basis) 1 wk before inoculation with PRRSV: 1) basal diet composed of corn, soybean meal, whey, and essential vitamins and minerals; 2) basal diet plus carbadox (0.055 g/kg of diet; as-fed basis); 3) basal diet plus Echinacea 2% (2% of the total diet); 4) basal diet plus Echinacea 4% (4% of the total diet). The diets were formulated to be isocaloric and isolysinic. Echinacea purpurea was purchased in powder form and determined by chemical analysis to contain 1.35% cichoric acid (as-fed basis). Seven days after starting the diets, all pigs in one room were intranasally inoculated with PRRSV isolate ATCC VR-2332 at a concentration of 10(4) tissue culture infectious dose50/mL. To monitor the effects of Echinacea and PRRSV challenge, BW and blood samples were obtained from all pigs at 7-d intervals. Serum samples were analyzed for the presence of PRRSV and PRRSV-specific antibodies. All challenged pigs became infected with PRRSV, and all unchallenged pigs remained free of infection. No differences (P > 0.10) in ADG, ADFI, or gain:feed (G:F) were observed in PRRSV-challenged compared with unchallenged animals. For PRRSV-challenged animals receiving diets supplemented with Echinacea at 2 or 4%, no differences (P > 0.10) were observed in ADG, ADFI, or G:F ratio. Among PRRSV-challenged pigs, dietary Echinacea did not affect (P > 0.10) the rate or level of the ELISA-detectable antibody response from d 7 to 42 or the level and duration of PRRSV in serum. For PRRSV-unchallenged animals receiving diets supplemented with Echinacea at 2 or 4%, no differences (P > 0.10) were observed in ADG, ADFI, and G:F ratio. Under the conditions of this study, dietary Echinacea did not enhance growth, exhibit antiviral effects to PRRSV, or show any evidence of immune enhancing properties.     

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。     

Impact of reduced dietary crude protein levels and phytase enzyme supplementation on growth response,slurry characteristics,and gas emissions of growing pigs

This experiment was carried out to evaluate the effect of reduced dietary crude protein (CP) levels supplemented with or without exogenous phytase on growing pigs. Six dietary treatments arranged in a 3 × 2 factorial arrangements of 3 CP levels (containing 14%, 16%, and 18% CP) supplemented each with or without 5,000 FTU/g phytase enzyme. Thirty growing pigs (average weight of 17.80 ± 0.10 kg) were allotted to the six dietary treatments in a complete randomized design. The final weight, daily weight gain, and feed conversion ratio (FCR) increased significantly with increasing CP levels. While, phytase supplementation improved (p = .044) FCR in pigs. Total solid and volatile solid content of the slurry were higher (p = .001) in pigs fed 14% and 16% CP diets supplemented with phytase when compared with other treatment groups. Concentration of methane gas emitted was lowest (p = .001) in the slurry of pigs fed 14% CP diet with or without phytase and those fed 16% CP diet with phytase supplementation. In conclusion, reduction in dietary CP levels resulted in reduced weight gain and poor FCR. While, reduced CP with phytase supplementation reduced concentration of methane gas emitted.     

Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs

Three experiments were conducted to determine the true ileal digestible (TID) Lys and sulfur AA (SAA) requirement and to compare the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and dl-MET as Met sources in nursery pigs. Experiment 1 included 2 studies: 1 was 662 nursery pigs (Triumph 4 x PIC C22; initial BW 12.2 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID Lys concentrations ranging from 1.10 to 1.50%; and the second study was 665 nursery pigs (Triumph 4 x PIC C22; initial BW 12.3 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID SAA concentration ranging from 0.63 to 0.90%. In Exp. 2, 638 nursery pigs (Triumph 4 x PIC C22; initial BW 13.0 +/- 0.16 kg) were allotted to the same 5 SAA dietary treatments as in Exp. 1. In Exp. 3, 1,232 pigs (Triumph 4 x PIC C22; initial BW 11.0 +/- 0.30 kg) were allotted to 1 of 7 dietary treatments. The basal diet (diet 1) was supplemented with high concentrations of synthetic AA but no Met; this resulted in a dietary concentration of TID Lys of 1.30% and TID SAA of 0.50%. Diets 2 to 7 were the basal diet supplemented with 3 equimolar levels of HMTBA or dl-MET to provide TID SAA concentrations of 0.56, 0.62, and 0.68%, respectively. In Exp. 1, increasing TID Lys from 1.10 to 1.50% increased ADG (quadratic; P < 0.05) and improved G:F (linear; P < 0.002). The pooled data of Exp. 1 (SAA study) and Exp. 2 indicated that increasing TID SAA from 0.63 to 0.90% increased ADG (quadratic; P < 0.01) and improved G:F (quadratic; P < 0.01). Various methods of analyzing the growth response surface indicated that the optimal TID Lys concentration ranged from 1.28 to 1.32% for ADG (Exp. 1), and the optimal TID SAA concentration ranged from 0.73 to 0.77% for ADG and 0.80 to 0.83% for G:F (pooled Exp. 1 and 2), respectively. In Exp. 3, increasing TID SAA concentrations from 0.50 to 0.68% resulted in a linear improvement of ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.001). The best fit comparison of HMTBA and dl-MET was determined by the Schwartz Bayesian Information Criteria index, which indicated the average relative efficacy of HMTBA vs. dl-MET was 111%, with 95% confidence interval of 83 to 138%, within the range of TID SAA tested. Thus, the TID Lys and SAA requirements of modern lean-genotype pigs from 11- to 26-kg were greater than the 1998 NRC recommendations, and both HMTBA and dl-MET as Met sources can supply equimolar amounts of Met activity.     

Effects of supplemental manganese on performance of growing-finishing pigs and pork quality during retail display

Crossbred barrows and gilts (n = 168) were used to test the effects of supplemental Mn during the growing-finishing period on performance, pork carcass characteristics, and pork quality during 7 d of retail display. Pigs were blocked by BW and allotted within blocks to pens (5 pigs/pen in blocks 1, 2, 5, and 6, and 4 pigs/pen in blocks 3 and 4). A total of 36 pens was randomly assigned to 1 of 6 dietary treatments, where the basal diets were formulated with (PC) or without (NC) Mn in the mineral premix, and supplemented with 0 or 350 ppm (as-fed basis) of Mn from MnSO4 or a Mn-AA complex (AvMn). Pigs were slaughtered at a commercial pork packing plant when the lightest block of pigs averaged 113.6 kg. During fabrication, boneless pork loins were collected and transported to Oklahoma State University, where 2.5-cm-thick LM chops were packaged in a modified atmosphere (80% O2 and 20% CO2) and subsequently placed in display cases (2 to 4 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. Pig performance was not (P > or = 0.44) affected by supplemental Mn; however, during the grower-II phase, pigs fed the basal diets including Mn consumed less (P < 0.02) feed and tended to be more efficient (P < 0.09) than pigs fed the basal diets devoid of Mn. Throughout the entire feeding trial, neither dietary nor supplemental Mn altered (P > or = 0.22) ADG, ADFI, or G:F. Chops from pigs fed the diets supplemented with MnSO4 received greater (P < or = 0.05) lean color scores and had a redder (greater a* and hue angle values), more vivid color than chops from pigs fed the diets supplemented with AvMn. Additionally, LM chops from pigs fed the PC diets supplemented with MnSO4 were darker (lower L* values; P < 0.05) than chops from pigs fed the NC diets or PC diets supplemented with 0 or 350 ppm of AvMn. Even though discoloration scores were similar during the first 4 d of display, chops from pigs fed the PC diets supplemented with MnSO4 were less (P < 0.05) discolored on d 6 and 7 of retail display than chops from pigs fed the PC or NC diets and diets supplemented with AvMn (dietary treatment x display time, P = 0.04). Results of this study indicate that feeding an additional 350 ppm of Mn from MnSO4 above the maintenance requirements of growing-finishing pigs does not beneficially affect live pig performance but may improve pork color and delay discoloration of pork during retail display.     

益生康代替抗生素对断奶仔猪生产性能及腹泻的影响

试验选用200头平均体重(6.95±0.11)kg、23日龄断奶三元杂交(杜×长×大)仔猪,研究玉米豆粕型日粮中添加益生康代替抗生素在断奶仔猪阶段的应用效果。配对试验设计2个处理,每个处理设5个重复,每个重复20头仔猪,公母各半混合饲养。处理1为抗生素对照组;处理2为添加0.15%益生康组,6～12kg阶段和12～20kg仔猪阶段。结果表明:6～12kg体重阶段与抗生素对照组相比,益生康增加仔猪日增重9.3%,提高日采食量10.6%,改善饲料转化率9.8%,仔猪腹泻发生率降低29.4%(P<0.05);12～20kg阶段日增重提高7.9%,改善饲料转化率15.8%。