Lower grinding intensity of cereals for dietetic effects in piglets?

The grinding intensity of cereals as ingredients of pelleted diets has various effects on pigs' health and performance. Feeding a coarsely ground diet (62.2% of particles > 1 mm; 10% < 0.4 mm) to piglets resulted in significantly higher starch contents in the hindgut chyme and increased counts of gram positive bacteria, but had no significant effect on dry matter (DM) digestibility. The combination of coarse grinding and addition of 1.2% potassium diformate (pdf) to the diet led to interesting effects in piglets infected experimentally with Salmonella Derby (single oral dose of 4.4 × 10¹⁰ cfu per piglet). In spite of the same infectious dosage in all piglets a marked reduction of Salmonella counts was found in chyme of piglets (sacrificed 4–6 h after experimental infection) when the coarsely ground diet including pdf was fed. It seems that coarse grinding of ingredients could have numerous dietetic advantages: reducing risks of Salmonella infection (faster elimination) as well as praebiotic effects in the hindgut by favouring gram positive bacteria like lactobacilli or gram positive cocci. Therefore, grinding intensity is worth to be reconsidered.     

液体发酵饲料对断奶仔猪肠道健康的影响

液体发酵饲料中含有大量种类繁多的益生菌及其代谢产物,它们可以改善饲料的消化特性,给断奶仔猪胃肠道提供酸性环境,调节肠道内菌群平衡,提高肠黏膜免疫系统的免疫功能,促进肠道健康,进而提高断奶仔猪的生长性能.     

甘露寡糖对保育猪的营养与保健作用

大量研究表明,甘露寡糖(MOS)通过积极影响断奶仔猪的肠道微生物菌群和肠道形态结构,加速由于断奶饥饿应激或采食固体饲料中抗原受损伤的肠黏膜上皮的修复,有助于保持仔猪断奶后肠道的完整性和消化吸收功能。在免疫反应方面,MOS通过促进抗原提呈增强断奶仔猪的抗病性,从而增强从先天性免疫应答向适应性免疫应答的转变。     

The effects of fructo-oligosaccharides or whole wheat on the performance and digestive tract of broiler chickens

1. The objective of this experiment was to study two feeding methods, which could potentially act on the gut microflora, the structure and/or the function of the digestive tract and thereby improve the performance of broilers. 2. Four dietary treatments were studied: a negative control (wheat based) with no additives (C), a positive control with 0.01 g/kg avilamycin (AV), a treatment with 0.6 g/kg fructo-oligosaccharides (FOS) and a treatment with the same composition as treatment C but in which a part or all (400 g/kg) of the wheat was given as whole wheat and a concentrate supplement (WW). The measurements were: the performance from 0 to 6 weeks, the bacterial counts at 3 and 6 weeks, the digestive tract morphology and the activity of some intestinal enzymes at 3 weeks. 3. The birds given AV had better daily live weight gain (DLWG) and feed conversion ratio (FCR) compared to treatment C. The birds given FOS had a lower feed intake and a lower DLWG than the birds on treatment C but their FCR was significantly improved. WW resulted in a numerically lower feed intake and a significantly lower DLWG than treatment C. With AV, the number of aerobic mesophilic bacteria in the caeca was reduced at 3 weeks. With WW, gizzard and pancreas weights were greater and the surfaces of the ileal crypts were larger. An increased activity of leucine aminopeptidase (LAP) in the duodenum was found for treatments AV, FOS and WW. 4. In conclusion, in this study, treatments WW and FOS reduced DLWG, which may have been due to a lower feed intake during the whole period. With WW, the FCR was not affected, maybe because of both positive and negative effects on digestive tract (higher gizzard and pancreas development and LAP activity; larger crypts). However, FOS improved FCR, which may be partly explained by the higher LAP activity.     

微生态制剂对仔猪肠道微生态调控的研究与应用进展

微生态制剂是一种安全、无毒、无污染、无残留的生物类饲料添加剂,具有提高仔猪生产性能、减少腹泻、增强机体免疫力、调节肠道菌群数量和维持肠道微生态平衡等功能,对仔猪肠道微生态的调节起着重要的作用。本文从微生态制剂的分类、作用机理、对肠道的作用等阐述国内外有关微生态制剂在仔猪中的应用及前景。     

Effect of benzoic acid on growth performance, nutrient digestibility, nitrogen balance, gastrointestinal microflora and parameters of microbial metabolism in piglets

In order to investigate the effects of benzoic acid on growth performance, nutrient digestibility, nitrogen balance and gastrointestinal microflora of piglets, we conducted a performance experiment and a separate balance study. The performance experiment involved four different dietary treatments: (1) basal diet (negative control); (2) basal diet supplemented with benzoic acid at 5 g/kg; (3) basal diet supplemented with benzoic acid at 10 g/kg; (4) basal diet supplemented with potassium diformate at 12 g/kg. Each dietary treatment was assigned to nine replicate groups, each consisting of two piglets. Live weight, daily weight gain, feed intake and feed conversion ratio were monitored as performance parameters over a 35-day period. Supplementation of the diet with benzoic acid resulted in a dose-dependent increase in feed intake and body weight gain and an improved feed conversion ratio. Piglets fed the diet supplemented with benzoic acid at 10 g/kg outperformed the control piglets in mean feed intake, body weight gain and feed conversion ratio by 9%, 15% and 6% respectively. Growth performance of the piglets fed the diet with benzoic acid at 10 g/kg was similar to that of piglets fed the diet supplemented with potassium diformate. In the balance experiment three groups of six piglets each were fed either a control diet or diets supplemented with benzoic acid at 5 or 10 g/kg respectively. Benzoic acid did not significantly affect nutrient digestibility but increased nitrogen retention. Piglets fed the diets supplemented with benzoic acid at 5 or 10 g/kg retained 5% and 6% more nitrogen, respectively, than control piglets. Supplementation of benzoic acid did not influence the pH value or the concentration of ammonia in the gastrointestinal tract but reduced the number of bacteria in the digesta. In the stomach the number of total aerobic, total anaerobic, lactic acid forming and gram-negative bacteria was reduced; in the duodenum the presence of benzoic acid reduced the number of gram-negative bacteria and in the ileum the number of total aerobic bacteria in a dose-dependent manner. Benzoic acid also considerably reduced the concentration of acetic acid in the duodenum. In conclusion, the data of this study suggest that benzoic acid exerts strong antimicrobial effects in the gastrointestinal tract of piglets and therefore enhances growth performance and nitrogen retention.     

Producing Salmonella-free pigs: a review focusing on interventions at weaning

Salmonella infection in pig production is typically endemic and largely asymptomatic. It is a cause of substantial concern among food safety bodies, prompting voluntary and legislative responses aimed at monitoring and reducing the number of Salmonella-infected animals entering the human food chain. Elimination of the problem at an early stage of production is highly desirable, and to this end the present review examines published evidence on the carriage of Salmonella by piglets before and after weaning, as well as evidence on the dynamics of Salmonella infection in the weaner and grower stages of pig production, the effects of maternal immunity, and risk factors for Salmonella excretion after weaning. Various interventions to reduce or eliminate Salmonella infection in young pigs have been tried, such as vaccination, competitive exclusion, treatments in feed and water, antibiotic administration, disinfection of animals, and segregated weaning to clean accommodation. The evidence on the effectiveness of these is considered, and the last is examined in some detail, as it appears currently to offer the best chance of eliminating Salmonella from growing stock.     

仔猪肠道健康的营养调控技术及其应用

肠道是营养物质的消化吸收器官,同时也是最大的免疫器官。断奶应激会使仔猪肠道受到严重的损伤,而肠道损伤又会引起肠绒毛萎缩、采食量降低、营养物质消化吸收障碍、免疫力降低等问题,从而使仔猪发生腹泻、消化不良以及生长速度缓慢等一系列症状。因此,通过营养对仔猪的肠道功能进行调控及肠道损伤进行修复,能够保障仔猪的肠道健康,提高成活率和生产性能,增加养殖效益。就仔猪肠道健康的营养调控技术及其应用进行了综述。     

Use of bacteriophages in combination with competitive exclusion to reduce Salmonella from infected chickens

Salmonella-spedfic bacteriophages (BP) and competitive exclusion (CE) were used to reduce Salmonella colonization in experimentally infected chickens. A "cocktail" of distinct phage (i.e., phage showing different host ranges and inducing different types of plaques on Salmonella Typhimurium [ST] cultures) was developed. The killing activity of the selected BPs on ST cultures differed significantly, as determined in in vitro killing assays. BPs were administered orally to the chickens several days prior and after ST challenge but not simultaneously. BPs were readily isolated from the feces of the BP-treated chickens approximately 48 hr after administration. A CE product consisting of a defined culture of seven different microbial species was used either alone or in combination with BP treatment. CE was administered orally at hatch. Salmonella counts in intestine, ceca, and a pool of liver/spleen were evaluated in Salmonella-challenged chickens treated with BP or with BP and CE. In both trials 1 and 2, a beneficial effect of the phage treatment on weight gain performance was evident. A reduction in Salmonella counts was detected in cecum and ileum of BP-, CE-, and BP+CE-treated chickens as compared with nontreated birds. In trial 1, BP treatment reduced ST counts to marginal levels in the ileum and reduced counts sixfold in the ceca. A reduction of Salmonella counts with BP, CE, and BP+CE treatments was evident in chickens from trial 2. Both CE and BP treatments showed differences in the reduction of Salmonella counts after challenge between spedmens obtained at days 4 and 14 postchallenge in ceca, liver/spleen, and ileum. The preliminary data presented in this report show that isolation and characterization of Salmonella-specific BP is uncomplicated and feasible on a larger scale. Results indicate a protective effect of both Salmonella-specific BPs and a defined competitive exclusion product against Salmonella colonization of experimentally infected chickens. These results are encouraging for further work on the use of BP as an effective alternative to antibiotics to reduce Salmonella infections in poultry.     

湿喂法在断奶仔猪生产中的应用

断奶仔猪采用湿喂法能提高仔猪的生产性能 ,改善其健康状况。一方面 ,液体日粮容易被仔猪接受 ,这样可以防止仔猪断奶后采食量的急速下降。另一方面 ,加水后成液态的饲料在自然条件下会发酵 ,这导致饲料中的乳酸菌数量增加、乳酸浓度上升、pH值下降。与喂干粉饲料相比 ,给断奶后仔猪喂液体日粮能够改善仔猪消化道的内环境 ,减少疾病 ,提高干物质采食量和日增重。     

饲用酶制剂作用机制的研究进展

分别从饲用酶制剂对畜禽日粮中抗营养因子，消化道内源酶活，微生物菌群，消化器官，外周血液激素水平以及畜禽机体免疫机能等方面的影响，对其改善畜禽生产性能的作用机制进行了探讨，饲用酶主要是通过消除抗营养因子（SNSP，消化酶抑制剂，细胞壁和植酸）和补充内源酶等方式提高日粮养分消化率，并减少有害微生物的过度繁殖，进而改善畜禽生产性能。     

The influence of grinding and pelleting of feed on the microbial composition and activity in the digestive tract of broiler chickens

1. The influence of feed grinding (coarsely or finely ground feed) and feed form (mash or pellets) on the intestinal environment was investigated in a growth experiment with broiler chickens taking the intestinal microflora, intestinal viscosity, and the activities of pancreatic digestive enzymes into consideration. 2. As compared to mash the feeding of pellets was associated with a significantly higher body weight due to increased feed intake and improved feed utilisation. 3. Pellet-fed birds had significantly decreased gizzard weights, a higher gizzard pH and a lower intestinal pH than mash-fed birds. 4. Pellet-fed birds had significantly lower relative pancreas weights and lower activities of pancreatic digestive enzymes (amylase, lipase, chymotrypsin), which indicates the existence of a feedback mechanism, which may have been triggered by the intestinal concentration of enzymatically hydrolysed products or of the respective digestive enzymes. 5. Pellet-fed birds had larger numbers of coliform bacteria and enterococci in the ileum and a reduced number of Clostridium perfringens and lactobacilli in the distal end of the digestive tract (caeca and rectum). Microbial fermentation in terms of volatile fatty acid (VFA) concentration was found to be significantly higher in the caeca of pellet-fed birds than in mash-fed birds.     

Influence of particle size and xylanase supplementation on the performance, energy utilisation, digestive tract parameters and digesta viscosity of broiler starters

1. The aim of the present experiment was to examine the influence of particle size and xylanase supplementation on the performance, energy utilisation, and gross morphological and histological parameters of the digestive tract of broiler starters fed wheat-based diets. The experimental design was a 2 x 2 factorial arrangement of treatments evaluating two wheat particle sizes (medium and coarse) and two levels of xylanase supplementation (without or with 1000 xylanase units/kg diet). The two particle sizes were achieved by grinding the whole wheat in a hammer mill to pass through 3 and 7 mm screens, respectively. Broiler starter diets, based on wheat and soybean meal, were formulated and each diet was fed ad libitum to 6 pens of 8 male broilers each from d 1 to 21 post-hatch. 2. Wheat particle size had no effect on the performance of broilers. Xylanase supplementation had no effect on weight gain and feed intake. However, a significant particle size x xylanase interaction was observed for feed per unit gain with xylanase lowering feed per gain only in the coarse particle size diet. Xylanase supplementation improved the nitrogen-corrected apparent metabolisable energy at both particle sizes. 3. Xylanase supplementation decreased the relative weight and relative length of all gut components. Villus height and crypt depth and total extent of the mucosal layer were unaffected by both wheat particle size and xylanase supplementation. 4. The apparent viscosity of intestinal digesta, determined over the physiological range of shear rates, was not influenced by xylanase addition or particle size. 5. The findings of this study suggest that the effectiveness of exogenous xylanase in broiler diets is influenced by wheat particle size.     

禁抗后仔猪细菌性腹泻的临床诊断与防治

为了促进食品安全和养猪业的健康发展，禁止在饲料中使用促生长抗生素势在必行。随着我国的饲料禁抗相关法规的推行，饲料企业被严格禁止在饲料生产过程中加入抗生素，这也导致了猪场疾病尤其是肠道疾病的高发，而仔猪肠道发育未完全，免疫系统未发育成熟，更容易发生严重的腹泻甚至死亡。文章对几种常见的仔猪细菌性腹泻疾病进行了回顾，病原包括大肠杆菌、沙门氏菌、魏氏梭菌，讨论了它们的临床症状与防控措施，为猪场在防控这些细菌性腹泻提供参考。     

饲料锌在育肥猪粪尿中的排泄规律研究

为研究饲料锌在育肥猪粪尿中的排泄规律,建立饲料锌摄入量与锌排泄量的预测模型,试验选用健康、体重相近的约克夏去势育肥公猪20头,随机分成5组,每组4个重复,每个重复1头猪,单独饲养于代谢笼中。对照A组饲喂基础日粮,锌添加量为0,试验B、C、D、E组分别饲喂在基础日粮中添加20、40、60、80 mg/kg锌的试验日粮(硫酸锌形式)。预试期7 d,正试期4 d。结果表明:(1)与对照组相比,除试验B组外,其他试验各组风干粪锌含量和粪锌日排泄总量随日粮锌添加水平或日粮总锌水平增加显著升高(P<0.05);经回归分析,日粮锌添加水平或日粮总锌水平与风干粪锌含量和粪锌日排泄总量存在极显著的线性回归关系(P<0.01),可用所建立的回归方程进行预测和控制。(2)各组尿锌含量和尿锌日排泄总量均无显著差异(P>0.05);经回归分析,日粮锌添加水平或日粮总锌水平与尿锌含量和尿锌日排泄总量无显著回归关系(P>0.05)。综上,日粮中多余的锌主要通过消化道从粪中排泄,可根据日粮中锌水平预测粪锌排泄量,从源头上控制锌对环境的污染。     

The influence of omega-3 polyunsaturated fatty acids (omega-3 pufa) on lactobacilli adhesion to the intestinal mucosa and on immunity in gnotobiotic piglets

The effect of application of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on intestinal colonization by Lactobacillus paracasei and on cellular immunity has been investigated in gnotobiotic pigs. The administration of polyunsaturated fatty acids positively affected the adhesion of Lactobacillus paracasei to the jejunal mucosa of gnotobiotic piglets. When compared to the control group, the number of Lactobacillus paracasei adhering to the jejunal mucosa was by 12% higher in piglets of the experimental group (5.10 log 10/cm2 vs. 4.55 log 10/cm2). The respective counts of Lactobacillus paracasei adhering to the ileal and colonic mucosa of 28 day old gnotobiotic piglets reached 4.45 and 5.05 log 10/cm2 in group C and 4.44 and 4.95 log 10/cm2 in group E. Omega-3 PUFA supplementation increased the phagocytic activity of neutrophils by almost 100% on day 28 of life as well as the subpopulations of lymphocytes (CD8) in the peripheral blood of germ-free piglets on day 21 of life. Our results indicate that the action of probiotics in the gut may be modulated by dietary PUFA. The stimulatory effect of PUFA upon adhesion of lactobacilli could be used for enhancing the effectiveness of probiotics in inhibiting digestive tract pathogens.     

Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli

The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ～10⁹–10¹⁰ CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.     

The influence of whole wheat feeding on Salmonella infection and gut flora composition in broilers

In an experiment with broilers infected with a rifampicin-resistant Salmonella Typhimurium strain at 15 days of age, it was demonstrated that whole wheat feeding influenced the course of infection. The pH in the contents of the gizzard decreased as the amount of whole wheat in the diet increased over time. Following infection, lower numbers of Salmonella Typhimurium were found in the gizzard and ileum of birds receiving whole wheat compared to pellet-fed birds. However, there was no difference with respect to the numbers of Salmonella Typhimurium in the ceca and rectum between the two experimental groups. Quantitative cultivation of different groups of bacteria belonging to the natural intestinal microflora showed that whole wheat feeding significantly reduced the numbers of Clostridium perfringens in the intestinal tract of the birds. The present results indicate that the gizzard has an important function as a barrier organ, one that prevents pathogenic bacteria from entering the distal digestive tract.     

Duration of anti-adhesive and bactericidal activities of milk from vaccinated sows on Escherichia coli O149 in the digestive tract of piglets during the nursing period.

Piglets were exposed orogastrically to Escherichia coli to enable study of the duration of anti-adhesive and bactericidal activities of milk of sows vaccinated with a K88 enriched E coli vaccine. There was a marked increase in the number of the challenge strain in the digestive tract of weaned piglets of all ages (between 888 and 2144 per cent). In contrast, there was a decrease in their number (75 per cent) in the day-old colostrum-fed piglets. When the piglets were two weeks old milk was still capable of reducing the rate of proliferation of the pathogen but at five weeks it proliferated at equal rates in the digestive tract of both suckling and weaned litter-mates. The rate of adhesion of the K88 positive E coli to the small intestine of colostrum deprived piglets was high (5 x 108/g). Rate of adhesion fell gradually in weaned piglets from 5.4 x 107/g at two weeks to 2.0 x 106/g at four to five weeks of age. In contrast, resistance of the small intestine of suckling pigs to adhesion by K88-positive E coli remained relatively stable through the five week period of nursing bacterial counts ranging from 5 x 104/g to 3 x 104/g of tissue.     

Effect of type of grinding of barley and dehydrated alfalfa on performance, digestion, and crude mucin ileal concentration in growing rabbits

The effects of type of grinding of barley and dehydrated alfalfa (DA) were tested in rabbits weaned at 35 d of age with an average BW of 846 ± 93 g. Four nonmedicated diets were arranged in a 2 × 2 factorial structure, with type of grinding (coarse grinding with a 4.5-mm screen or fine grinding with a 1.5-mm screen) of barley (TGB) and DA (TGDA) as the main factors. A total of 1,056 mixed-sex rabbits (264 per diet) were fattened until d 63. Most of these rabbits (216 per diet) were housed in pairs and were used only to record mortality rate. Mortality was also recorded for the remaining 192 rabbits, which were housed individually and used to determine growth performance. From this group, 100 rabbits were used to determine digestive traits. Apart from those rabbits, a different group of 88 rabbits (44 housed individually and the remaining 44 housed in pairs) was used in the digestibility trial. All rabbits in this group were used to determine ileal digestibility (13 pools of ileal digesta per diet) and ileal mucin concentration (6 pools of ileal digesta per diet), whereas only the 44 individually housed rabbits were used to assess the fecal digestibility coefficients (11 rabbits per diet). Last, a jejunal sample was excised from 32 of the 44 individually housed rabbits to determine mucosal histology. Treatments did not affect ADG, ADFI, or G:F in the entire fattening period, but in the 49- to 63-d period, the diet containing both finely ground barley and DA reduced ADFI (P=0.08) compared with the other treatments (130 vs. 137 g). Moreover, this diet increased total digestive tract (4.76%, P=0.08) and cecal content (11.3%, P=0.08) weights compared with the other 3 treatments. Pylorus (P=0.09) and mixed digesta (P=0.06) pH, respectively, were reduced from 1.53 and 1.59 to 1.37 and 1.44 when both barley and DA were finely instead of coarsely ground. Grinding both barley and DA coarsely reduced the ileal digestibility of starch (0.899 vs. 0.936, P=0.06), increased (P < 0.01) its ileal flow and content in the feces to 1.66 g/d and 7.42 g/kg of DM, respectively, and led to decreased fecal digestibility (0.932 vs. 0.951, P < 0.01) compared with fine grinding. Coarse DA shortened villi (612 vs. 704 μm, P=0.02), increased crypt depth (121 vs. 92.1 μm, P=0.01), and reduced the villus:crypt ratio (5.08 vs. 7.66, P < 0.01) compared with finely ground DA. Furthermore, the greatest ileal crude mucin (148 vs. 107 g/kg of DMI, P=0.02) and sialic acid (71.7 vs. 61.7 mg/kg of DMI, P=0.04) concentrations were reported in rabbits receiving the diet with both coarsely ground barley and DA. Finally, mortality rate was not influenced by treatments, with an average of 9.64%. In conclusion, the diet containing finely ground barley and coarsely ground DA did not increase the weight of cecal contents, resulting in increased feed intake and leading to increased ileal digestibility and reduced ileal flow of starch.