Effects of feed particle size at dietary presence of added organic acids on caecal parameters and the prevalence of Salmonella in fattening pigs on farm and at slaughter

In a field study with fattening pigs, effects of feed particle size at the dietary presence of organic acids on Salmonella prevalence were measured. On two farms (f1/f2), each holding ～800 pigs, diets based on finely ground (control) or coarsely ground ingredients (experiment) were fed as crumbs. On f1 both control and experimental grower and finisher diets contained identical concentrations of formic and propionic acid (0.4% and 0.2% respectively). On f2 only finisher diet of the experimental group contained 1.2% potassium diformate. At the start of the fattening period no statistical differences were measured between Salmonella prevalence in animals fed control and experimental diets on both farms. At slaughter Salmonella prevalence in caecal contents was lower (p < 0.05) on f1 in animals fed the experimental diet. Furthermore, the number of seronegative meat juice samples taken from these animals [optical density (OD) <10] was higher (p < 0.001); seropositive as well as distinct seropositive samples (OD ≥20 and ≥40 respectively) were less frequent (p < 0.01) compared to samples from animals fed the control diet. Feeding the experimental diet on f2 resulted in a lower Salmonella detection rate in faeces before slaughter (p < 0.01). Salmonella prevalence was lower in caecal content at slaughter for pigs fed the experimental diet compared to those fed control diet (p < 0.0001). The number of distinct seropositive meat juice samples (OD ≥40) was lower (p < 0.01) for pigs fed the experimental than for those fed the control diet. In comparison to pigs in the control group, starch concentrations in the caecal content from pigs in the experimental groups on both farms were higher (p < 0.05) and the pH values lower (p < 0.05). Propionate (p < 0.0001) and butyrate (p < 0.01) concentrations were higher in the caecal content taken from pigs in the experimental group on f2.     

自配料与商品料对生长猪育肥效果比较

选用 12头平均体重 36 6± 0 9kg(P >0 0 5 )、日龄相近、健康的大约×清平二元杂交生长猪 ,随机分为Ⅰ、Ⅱ、Ⅲ组处理 ,分别饲喂自配料 +自配添加剂、自配料、商品料进行试验 ,试验期为 4 0d。结果显示 :(1)Ⅰ、Ⅱ、Ⅲ组处理的料肉比分别为 3 5 3、3 5 7、3 80 ,Ⅰ组比Ⅲ组料肉比下降 7 1% ,Ⅱ组比Ⅲ组下降 6 1% ;饲料成本下降 18 8%。 3组间的平均日增重无显著差异 (P >0 0 5 )。 (2 )增重营养成本 ,DE :Ⅰ组比Ⅲ组下降 5 0 % ,Ⅱ组比Ⅲ组下降 4 0 % ;CP :Ⅰ组比Ⅲ组下降 5 0 % ,Ⅱ组比Ⅲ组下降 3 6 %。     

加工工艺参数对杀灭肉鸡饲料中沙门氏菌的影响

本试验目的是研究调质温度、时间和水分对杀灭肉鸡饲料中沙门氏菌数量级的影响,建立调质工艺杀灭饲料中沙门氏菌的数量级与温度、时间和水分等工艺参数间关系的数学模型,优化出杀灭饲料中4个数量级沙门氏菌的调质工艺参数。在实验室条件下,采用3因子3水平Box-Behnken模型的响应面设计。温度水平为60、80、100℃;时间水平为20、160、300s;水分水平为5%、10%、15%。温度越高,时间越久,水分越大,调质工艺杀灭饲料中的沙门氏菌的数量级越大。最大效应值为6.51,最小效应值为0.38,获得了相应的数学模型,研究还得到10组可以杀灭4个数量级沙门氏菌的调质工艺参数。这说明响应面设计可以应用于颗粒饲料加工过程中调质工艺参数的优化。试验结果表明,当调质温度为100℃,时间20s时,水分最少为13.78%;调质时间20s,水分15%时,温度最少应为95.2℃,这在实际肉鸡颗粒饲料加工中是可行的。     

内源性调控对猪采食量的影响

采食量是猪营养的第一制约因素。本文就影响猪采食量调节的因素以及当前内源性调控采食量的一些初步研究作一简要介绍。     

日粮中添加发酵饲料对育肥猪养分消化率及肠道菌群的影响

为研究日粮中添加不同水平的发酵饲料对育肥猪养分消化率及肠道菌群的影响,试验选用560头杜×长×大三元育肥猪[(75.37±2.65)kg],根据体重、性别随机分为7组,每组5个重复,每个重复16头,对照组饲喂育肥猪日粮,试验组分别在育肥猪日粮中添加5%或10%的发酵饲料A、B、C,饲喂21 d后每组选5头育肥猪肛门采集新鲜粪便测定肠道菌群多样性;并在饲喂第29天和第30天,各组每个重复连续收集粪便混合后测定养分消化率。结果表明:日粮中添加发酵饲料对育肥猪粗蛋白质、能量和干物质的消化率没有显著影响(P>0.05),相比对照组,饲喂发酵饲料组的粗蛋白质消化率有所提高(最高组提高2.9%);同时肠道菌群中乳杆菌属丰度有所增加,表明在日粮中添加一定比例的发酵饲料可以改善育肥猪养分消化率和肠道健康。     

肥育猪饲粮中添加苜蓿草粉对其生产性能、消化率及血清指标的影响

本研究目的在于评价在玉米－豆粕型基础饲粮中添加苜蓿草粉对肥育猪的利用价值。选取体重约５０ｋｇ的杜×长×大三元杂交猪４０头,采用单因子完全随机设计,分为５个组,每组４个重复,分别在饲粮中添加不同比例的苜蓿草粉,依次为：０（对照组）,１０％（试验Ｉ组）,１５％（试验ＩＩ组）,２０％（试验ＩＩＩ组）,２０％＋０．１％纤维素酶（试验ＩＶ 组）,各组主要营养指标相同。测定肥育猪饲喂含不同水平苜蓿草粉饲粮后主要生产性能、消化率及血清中主要生化指标的变化。结果表明,１）试验ＩＩ、ＩＩＩ、ＩＶ 组平均日增重、采食量较对照组明显提高,而试验ＩＩ、ＩＶ 组的料肉比明显降低,因此,添加１５％的苜蓿草粉或２０％的苜蓿草粉＋０．１％ 纤维素酶有利于提高肥育猪的体重及饲料转化率。２）试验Ｉ、ＩＩ组和对照组相比,其干物质、粗蛋白质、粗灰分、中性洗涤纤维的表观消化率均不同程度提高;虽然试验ＩＩＩ、ＩＶ 组上述４项指标的表观消化率和对照组相近或稍高,但试验ＩＶ 组各主要指标优于试验ＩＩＩ组,说明添加１０％和１５％的苜蓿草粉有利于提高营养物质的表观消化率,苜蓿草粉添加至２０％时加纤维素酶对各项指标消化率有改进。３）肥育猪饲粮中添加苜蓿草粉,降低了其血液甘油三酯、胆固醇及低密度脂蛋白胆固醇含量,升高了高密度脂蛋白胆固醇含量。试验证明,在肥育猪饲粮中添加１５％紫花苜蓿草粉对肥育猪生产性能、营养物质消化率及血清生化指标的改善有利,苜蓿草粉降低血液胆固醇的功能可能是其中皂苷的作用。     

加强生长育肥猪的饲养管理减少疾病的发生

在整个养猪生产中,育肥是养猪的最后一个生产环节,是检测猪种选择是否正确,营养饲料是否适合,饲养技术是否过硬,疫病防控是否完善的关键,不仅关系到市场供应,而且对猪场经济效益有着重要影响,也是发展养猪生产的最终目的。     

BGB饲料对生长猪和肥育猪生长性能的影响

本试验旨在评估BGB饲料对生长猪和肥育猪生长性能的影响。试验分两期进行,试验1选用初始体重为19.02±0.04kg的阉公猪72头,随机分为3组。以玉米-豆粕型日粮为基础日粮,对照组添加60mg/kg盐霉素,试验组分别添加5%、10%的BGB饲料。试验期28d,计算日采食量(ADFI)、日增重(ADG)和饲料转化率(FCR)。试验2选用初始体重为57.01±0.6kg的阉公猪54头,试验期35d,试验期日粮处理与饲养管理同试验1。试验1结果表明:处理组与对照组各项测定指标无显著差异(P>0.05),但在饲喂后期,5%BGB添加组的ADG比对照组提高7.8%,饲料转化率改善10.8%。试验2结果表明:处理组与对照组各项测定指标无显著差异(P>0.05),在饲喂后期,5%、10%BGB添加组的ADG分别比对照组改善了10.7%和4.0%。从全期结果来看,处理组的效果要优于对照组,5%BGB添加组效果最好。以上两个试验表明:添加BGB可以达到与添加抗生素相似的生产水平,对生长性能有一定的促进作用,最适添加量为5%。     

不同配合料饲喂育肥猪对比试验研究

[目的]通过比较2种不同配合料饲喂育肥猪的饲养效果和效益情况,筛选出适合试验猪场生产所需的饲料品种。[方法]选择体重在（47.3±2.5）kg的洋三元猪40头作为试验对象,将其分为2组,并分别饲喂2种配合料55 d,当体重达到90 kg左右后,对其生长性能进行对比分析。[结果]在试验阶段结束后,大北农饲料组的实验猪在头均末重和头均总增重上分别极显著高于金格力饲料组11.29%和16.32%（P〈0.01）,但其料肉比却极显著低于金格力饲料组13.64%（P〈0.01）。[结论]综合以上因素,并从养殖场的经济效益出发,可以认为大北农公司的配合料更适合推广应用。     

降低生猪料肉比技术优化研究

降低料肉比,可以在饲喂量一定时多生产猪肉,提高生猪生长速度,既减少生产成本,又提高利润.本研究在配方发酵生物饲料的基础上,采用单因素试验和响应面中试优化,获得继续降低料肉比饲料饲养最佳优化参数为日粮赖氨酸10 g+蛋氨酸5 g、日饮小分子活性水用量1.0 L、日粮生物有机硒(以Se计)1.5 mg+维生素E 150 m...     

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

The aim of this study was to evaluate the impact of the pre-slaughter process on Salmonella caecal contamination of pigs at slaughter. An observational study was carried out in 2001 on 101 conventional farrow-to-finish pig farms. On each farm, one batch of contemporary pigs was followed from the end of the fattening period until slaughter. The Salmonella bacteriological status of the batches was assessed by environmental samples of faecal material. The serological Salmonella status was obtained on 30 individually identified market-age pigs using an indirect ELISA test. At the slaughterhouse, 25 g of caecal contents were taken from 10 of the identified pigs. Faecal and caecal material were analysed according to a classical bacteriological method. A questionnaire was designed to obtain information about the type of feeding during the fattening period (dry versus wet), the duration of fasting on the farm before leaving for the slaughterhouse, the duration of transport between the farm and the slaughterhouse, the holding time in lairage at the slaughterhouse and loading and unloading conditions on the farm and at the slaughterhouse. To assess the relationships between these factors and the Salmonella caecal status of the pigs and the batches, two logistic models were fitted at the individual and at the batch level, respectively. The first analysis was performed using a random effects logistic regression model. The second analysis was based on a cumulative logit model with a positive caecal rate classified into three classes as the outcome variable. The results showed that the Salmonella status of market-age pigs assessed on the farm either by serological or bacteriological examinations and the time spent in lairage before slaughtering played a crucial role on caecal contamination. In the light of these results, actions should be considered both on the farm and at the slaughterhouse to decrease the risk of Salmonella contamination of the caecal contents.     

非常规饲料原料对生长育肥猪屠宰性能和肉品质的影响

文章旨在评估日粮添加非常规饲料原料对生长育肥猪屠宰性能和肉品质的影响。试验将12周龄平均初始体重为(33.15±1.23)kg的450头(公母各半)生长猪随机分为3组,每组5个重复,每个重复30头猪。对照组饲喂常规玉米-豆粕-小麦型日粮,处理1组饲喂含有30%马铃薯茎叶和10%苜蓿草的日粮,处理2组饲喂含有30%马铃薯茎叶、10%苜蓿草及0.5%中草药提取物的日粮,试验共开展10周。结果:处理1和2组较对照组显著提高生长猪屠宰率和背膘厚度(P<0.05),但瘦肉率和眼肌面积显著降低(P<0.05)。日粮处理与性别对屠宰率、胴体长度、眼肌面积及背膘厚度的影响具有显著交互作用(P<0.05)。处理组较对照组显著提高了肌肉系水力(P<0.05),处理2组肌肉的适口性显著高于对照组(P<0.05)。此外,处理组肌肉粗蛋白质含量显著高于对照组(P<0.05),而脂肪含量显著降低(P<0.05)。结论:与常规饲料相比,非常规饲料对生长育肥猪肌肉感官特性表现出积极影响,特别是改善了适口性和嫩度。     

Effects of early and late feed restriction or feed withdrawal on growth performance,ascites and blood constituents of broiler chickens

A study was conducted with male broilers to determine the effects of early and late feed restriction or feed withdrawal. In the experiment five treatments were represented by three replicate floor pens, each containing 20 broilers. The experimental procedure was a completely randomized design. The treatments were ad libitum (AL), 25% (FR-25) and 50% (FR-50) feed-restricted or 8 h (FW-8) and 16 h (FW-16) feed withdrawal regimes, respectively. FW-16 regime significantly reduced weight gain to 21 days of age compared to AL or FR-25 regimes (P<0.05). However, the overall weight gains between 9 days and 42 days of age were not significantly affected by the treatments. FW-8 and FW-16 broilers consumed significantly less feed than either AL or FR broilers between 9 and 21 days (P<0.05), however FW-8 and FW-16 broilers had similar feed intake to AL or FR-25 and FR-50 broilers between 9 and 42 days of age. Feed: gain, abdominal fat pad and heart weights, mortality, death due to ascites, and the incidence of leg disorders were unchanged by feeding regimes, although the incidence of ascites in FW-16 was significantly (P<0.05) lower than AL fed broilers. Blood constituents, such as albumin, total cholesterol, ketone bodies, glucose, chlorine, lactate dehydrogenase, alanine aminotransferase and creatine were also significantly affected by feeding regimes (P<0.05).     

饲料中添加不同水平的发酵豆渣对育肥猪生长性能、屠宰性能及经济效益指标的影响

为研究饲料中添加不同水平的发酵豆渣对育肥猪生长性能、屠宰性能及经济效益指标的影响,采用单因素随机设计试验,选择体重相近的健康育肥猪80头随机分成4组,每组20个重复,每个重复1头,1组饲喂基础日粮为对照组,试验2、3、4组分别在基础日粮中添加5％、10％、15％发酵豆渣,预试验7 d,试验期56 d.结果表明:(1)试...     

Selecting the hologenome to breed for an improved feed efficiency in pigs—A novel selection index

Most traits in animal breeding, including feed efficiency traits in pigs, are affected by many genes with small effect and have a moderately high heritability between 0.1 and 0.5, which enables efficient selection. Since the microbiota composition in the gastrointestinal tract is also partly heritable and was shown to have a substantial effect on feed efficiency, the host genes affect the phenotype not only directly by altering metabolic pathways, but also indirectly by changing the microbiota composition. The effect of the microbiota composition on the breeding value of an animal is the conditional expectation of its breeding value, given the vector with microbiota frequencies, that is The breeding value of an animal can therefore be decomposed into a heritable contribution that arises from an altered microbiota composition and a heritable contribution that arises from altered metabolic pathways within the animal, so Instead of selecting for breeding value , an index comprising the two components and with appropriate weights, that is , can be used. The present study shows how this breeding strategy can be applied in pig genomic selection breeding scheme for two feed efficiency traits and daily gain.     

不同配方日粮对35日龄断奶仔猪饲喂效果观察

选择９６头三元杂交仔猪分为两组，试验组饲喂以新技术配制的日粮，对照组喂常规日粮。结果表明，断奶前两组生产性能没有显著差异，断奶后一周，试验组日增重提高９７ｇ（Ｐ＜０．０５），每千克增重少耗料０． ２２ｋｇ（Ｐ＞０． ０５），腹泻率降低 １１． ２４％。对照组的断奶应激对以后的生产性能产生一定影响。     

饲料中添加发酵豆粕对育肥猪生长性能、屠宰性能及经济效益的影响

为研究饲粮中添加发酵豆粕对育肥猪生长性能、屠宰性能及经济效益的影响,试验选择体重相近、健康的三元杂交育肥猪80头随机分成4组,每组20个重复,每个重复1头,1组饲喂基础日粮为对照组,试验2、3、4组分别用发酵豆粕替代基础日粮中50％、75％、100％的豆粕,预试验7 d,试验期56 d.结果表明:(1)试验3、4组的平...     

Survival of Salmonella in the crop contents of market-age broilers during feed withdrawal.

Recent studies have indicated that crop contamination increases during preslaughter feed withdrawal and that contaminated crop contents may serve as an important source of Salmonella entry into poultry processing plants. During the present study, we evaluated the effect of preslaughter feed withdrawal on crop pH and Salmonella crop contamination in broilers from three commercial broiler flocks. The effect of experimental feed withdrawal on crop pH, lactic acid concentration, and Salmonella crop contamination was also evaluated in market-age broilers challenged experimentally with Salmonella typhimurium. Crop pH increased significantly (P < 0.05) from 3.64 +/- 0.25 before feed removal to 5.14 +/- 0.72 after 8 hr of feed withdrawal in broilers from commercial flocks. The incidence of Salmonella crop contamination in the commercial broilers increased (P < 0.05) from 3.3% before feed removal to 12.6% after 8 hr of feed withdrawal. Similarly, crop pH increased (P < 0.05) by a magnitude of approximately 1 unit in broilers after 8 hr of experimental feed withdrawal. The population of S. typhimurium in the crops of the experimentally challenged broilers increased (P < 0.05) by approximately 1 log unit during the 8-hr experimental feed withdrawal. The concentration of lactic acid in the crop of the broilers during experimental feed withdrawal decreased (P < 0.01) from a range of 119-135 mumol/ml before feed removal to a range of 22-32 mumol/ml after 8 hr of feed withdrawal. The results indicated that feed withdrawal resulted in a decrease in lactic acid in the crop, accompanied by an increase in crop pH, and an increase in Salmonella crop contamination.     

重金属对饲料污染的分析及防制措施

文章综述了我国饲料重金属污染的种类、污染物的主要来源、污染物的特性及危害机理,并简要阐述了预防饲料重金属污染的措施。