Effects of encapsulated butyrate and salinomycin on gut leakage and intestinal inflammation in broilers.

1. The objectives of this study were to i) compare the effects of a commercial product providing encapsulated butyrate (EB) in combination with salinomycin in diets of broilers with impaired intestinal integrity and ii) to identify easy-to-measure biomarkers to evaluate intestinal integrity and health.2. In total, 672 one-day-old male broilers (Ross 308) were randomly assigned to three experimental groups (eight replicates/group): no dietary supplement (control); EB (500 mg/kg, UltraGuard™-DUO, Devenish, Ireland); salinomycin (69 mg/kg feed, Sacox® 120). Impaired gut integrity was induced by a 10 times overdose of a commercially attenuated live vaccine against coccidiosis (Hipracox®, Hipra) on d 17 combined with a grower feed providing rye (50 g/kg diet).3. Improved intestinal integrity and functionality were reflected by reduced fluorescein isothiocyanate-dextran (FITC-D) plasma levels, reduced bacterial translocation to the liver (on d 21) and increased plasma colouration level on d 21 after dietary supplementation of salinomycin, compared to a non-supplemented control diet. Both EB and salinomycin reduced plasma levels of D-lactate (P < 0.05).4. An anti-inflammatory effect of salinomycin was indicated as the transient increase in circulating monocytes observed in the EB and control group from 20 to 28 d of age was slightly but not significantly reduced, in the salinomycin-fed group. Interestingly, greater expression of tumour necrosis factor α (TNF-α) and mucin 2 (MUC2) genes (P = 0.039 and P = 0.067, respectively) were detected in the group receiving salinomycin.5. These effects may have collectively contributed to the significantly improved performance of broilers supplemented with salinomycin. The results indicated that EB at 500 mg/kg in feed, in contrast to salinomycin, neither supported gut health nor modulated intestinal integrity in broilers.

Helminth infection is associated with hen mortality in Danish organic egg production.

The aim of this study was to investigate whether two highly prevalent helminth infections (Ascaridia galli and Heterakis species) are associated with an increased mortality rate for hens at the peak of lay. An observational event study with 11 farms was conducted between 2012 and 2013, with weekly mortality recordings and grouping of the farms into low-infected with A galli and Heterakis species (0-200 epg of faeces) or high-infected (over 200 epg of faeces). Survival analysis was performed using a discrete time proportional hazards model. The difference between the hazard functions for low-infected farms and high-infected farms in either summer (August to September) or winter (January to March) were analysed. No statistically significant associations were found between the mortality rate in winter and summer in low-infected farms. However, the mortality rate was doubled for hens from high-infected farms observed in the summer season compared with hens from low-infected farms (winter and summer), whereas high-infected farms observed in the winter did not have a significant association between mortality rate and season compared with low-infected farms (summer and winter). The results suggest that the mortality in organic egg production may be reduced by measures to control A galli and Heterakis species infections.

The influence of feeding crimped kernel maize silage on broiler production, nutrient digestibility and meat quality.

Two experiments were carried out in parallel with male Ross 308 broilers over 37 d. An experiment with a total of 736 broilers was performed to study the effect of dietary inclusion of crimped kernel maize silage (CKMS) on broiler production and meat quality. Another study with 32 broilers was carried out from 21 to 25 d to investigate the inclusion of CKMS on nutrient digestibility. In both trials, 4 dietary treatments were used: wheat-based feed (WBF), maize-based feed (MBF), maize-based feed supplemented with 15% CKMS (CKMS-15) and maize-based feed supplemented with 30% CKMS (CKMS-30). Compared with MBF, the dry matter (DM) intakes of broilers receiving CKMS-15 and CKMS-30, respectively, were numerically 7.5 and 6.2% higher and feed conversion ratio 6 and 12% poorer (significant for 30% CKMS), although there were no significant differences in AME content between the three diets. At 37 d, the body weight of birds receiving 15% CKMS was similar to birds fed with MBF. However, the inclusion of 30% CKMS decreased broiler growth. Dietary supplementation with CKMS significantly reduced the apparent digestibility of phosphorus. The fat digestibility was significantly lower for CKMS-30 than for the other three diets. Broiler mortality decreased significantly when CKMS was added to the diet. The consumption of drinking water was significantly lower in all maize-based diets as compared to WBF and was lowest in broilers fed with CKMS-30. An improved litter quality in terms of DM content and a lower frequency of foot pad lesions was observed with broilers supplemented with both dietary levels of CKMS. The addition of CKMS to maize-based diets increased juiciness, tenderness and crumbliness of the meat. In conclusion, the dietary supplementation of 15% CKMS had no negative effect on broiler growth and positively influenced bird welfare in terms of mortality and foot pad health. Therefore, the addition of 15% CKMS to maize-based diets is considered an advantageous feeding strategy in broiler production.

Short communication: Effects of Bos taurus autosome 9-located quantitative trait loci haplotypes on enzymatic mastitis indicators of milk from dairy cows experimentally inoculated with Escherichia coli.

The aim of this study was to investigate the effect of a quantitative trait locus associated with mastitis caused by Escherichia coli, with one haplotype being more susceptible (HH) and another being more resistant (HL) to E. coli mastitis, on the activity of 4 inflammatory related milk enzymes. In particular, we investigated the suitability of ß-glucuronidase (GLU) as an early indicator of E. coli mastitis. Besides GLU, the enzymes l-lactate dehydrogenase (LDH), N-acetyl-ß-d-glucosaminidase (NAGase), and alkaline phosphatase were included. The study was conducted in an experimental setup with 31 Holstein cows divided into 4 groups representing repeated experiments and, within group, divided according to quantitative trait locus haplotype. All cows were inoculated with viable E. coli, and milk samples were collected 27 times from -6 to 396 h post-E. coli inoculation (PI). Activity of the 4 enzymes in milk, somatic cell count (SCC), daily milk yield, viable E. coli counts, and results of a semiquantitative polymerase chain reaction for pathogen detection, were all analyzed with a repeatability model. The response variables all expressed a strong reaction to the E. coli infection. Daily milk yield decreased significantly at 12 h PI and bacteria counts increased 100-fold and peaked at 18 h PI, which was validated by PCR. Also, SCC started to increase at 12 h PI and increased on average 70 times; however, no significant differences in SCC level were detected between HH and HL cows at any sampling point. The enzymes LDH, NAGase, and alkaline phosphatase showed similar responses, with a significantly increased activity and higher peak values for the HH than the HL cows. Significant differences between HH and HL cows were detected at different time points for these 3 enzymes, but not after adjusting P-values for multiple testing. A different pattern was also observed for GLU, where HL cows expressed the highest peak activity. Indication of differences in GLU activity between the 2 haplotype groups was only seen at 60 h PI. It was concluded that HL and HH cows expressed similar response patterns after E. coli infection but with differences in the size and profile of the activity of the 4 enzymes. The enzyme GLU was an equally good indicator of E. coli mastitis compared with the other studied enzymes, although it showed a slower response compared with LDH and NAGase.

Clostridium perfringens challenge and dietary fat type affect broiler chicken performance and fermentation in the gastrointestinal tract.

The aim of the present work was to examine how different fats commonly used in the feed industry affect broiler performance, nutrient digestibility and microbial fermentation in the gastrointestinal tract of broiler chickens challenged with virulent Clostridium perfringens strains. Two experiments were carried out, each including 480-day-old male broilers (Ross 308), which were randomly distributed to eight experimental groups using six replicate pens per treatment and 10 birds per pen. In Experiment 1, birds were fed diets containing soybean oil, palm kernel fatty acid distillers, rendered pork fat and lard. In Experiment 2, birds were fed diets containing rapeseed oil, coconut oil, beef tallow and palm oil. In both experiments, the birds were either not challenged or challenged with a mixture of three C. perfringens type A strains. Irrespective of the fat type present in the diet, C. perfringens did not affect broiler chicken body weight gain (BWG) and mortality in either of the two experiments. The BWG was affected by dietary fat type in both experiments, indicating that the fatty acid composition of the fat source affects broiler growth performance. In particular, the inclusion of animal fats tended to improve final BW to a greater extent compared with the inclusion of unsaturated vegetable oils. In Experiment 2, irrespective of the dietary fat type present in the diet, C. perfringens challenge significantly impaired feed conversion ratio in the period from 14 to 28 days (1.63 v. 1.69) and at 42 days (1.65 v. 1.68). In both experiments apparent metabolizable energy values were affected by dietary fat type. Irrespective of the fat type present in the diet, C. perfringens challenge decreased the digesta pH in the crop and ileum, but had no effect in cecal contents. Moreover, in Experiment 1, total organic acid concentration in the ileum was two to three times lower on soybean oil diets as compared with other treatments, indicating that C. perfringens as well as dietary fat type significantly affects microbiota activity in the broiler chicken gastrointestinal tract.

Antihistomonal effects of artemisinin and Artemisia annua extracts in vitro could not be confirmed by in vivo experiments in turkeys and chickens.

Five different Artemisia annua-derived materials (i.e. dry leaves, pure artemisinin, and hexane, dichloromethane or methanol extracts of leaves) were screened for their in vitro activities against six clonal cultures of Histomonas meleagridis. Except for the methanol extract, all tested materials displayed in vitro activity against all tested protozoal clones. Neither the dry plant material, extracts nor artemisinin showed any antibacterial activity against the xenic bacteria accompanying the six H. meleagridis clones at concentration levels identical to the antihistomonal setting. The dichloromethane extract of dry leaves (Ext-DCM) (minimal lethal concentration=1.0 mg/ml) and artemisinin (half-maximal inhibitory concentration=1.295 mg/ml) had the most promising antihistomonal properties and were therefore subsequently tested in a standardized experimental infection model in both turkeys and chickens infected with clonal H. meleagridis. There were no differences between treatment groups, where all infected turkeys showed severe clinical histomonosis and demonstrated severe typhlohepatitis typical for histomonosis. Consistent with the infection model used, the infected chickens did not show any adverse clinical signs but contracted severe lesions in their caeca 7 and 10 days post infection (d.p.i.), liver lesions were absent to mild after 7 d.p.i. and progressed to severe lesions at 10 d.p.i.; thus no differences between treatment groups were observed. In conclusion, neither artemisinin nor Ext-DCM was able to prevent experimental histomonosis in turkeys and chickens at the given concentrations, which is contrary to the antihistomonal effect noticed in vitro even though the same clonal culture was used. The results of this study therefore clearly demonstrate the importance of defined in vivo experimentation in order to assess and verify in vitro results.

Lyophilized Carnobacterium divergens AS7 bacteriocin preparation improves performance of broiler chickens challenged with Clostridium perfringens.

The present study aimed to investigate the effects of Carnobacterium divergens AS7 bacteriocin (divercin AS7) on growth performance, digestibility, fermentation processes, selected microbial populations, and histomorphology in broiler chickens challenged with a mixture of 3 Clostridium perfringens isolates. In total, 480 one-day-old male Ross 308 chicks were randomly assigned to 4 experimental groups (12 replicate pens of 10 birds per treatment). The diets were either nonsupplemented or supplemented with a lyophilized preparation of divercin AS7. On d 18, 19, and 20, half of the birds were challenged twice a day with the C. perfringens mixture. The C. perfringens challenge did not influence broiler BW gain but impaired feed conversion ratio from d 29 to 42 (P=0.023) and throughout the experimental period (P=0.038). Moreover, the C. perfringens challenge resulted in decreased pH levels of crop, gizzard, and ileum contents (P<0.05) and reduced the numbers of lactic acid bacteria in the ceca (P=0.01). Divercin supplementation decreased broiler feed intake from d 14 to 28 (P=0.001) but increased BW gain from d 29 to 42 (P=0.048). The divercin supplementation increased the AMEn level (P=0.015) and reduced digesta pH in crop and ileum (P=0.004 and P=0.042, respectively), but of nonchallenged birds only. Divercin supplementation, moreover, increased gizzard lactate concentrations (P=0.003). The crop concentrations of lactate and succinate and the ileum concentration of lactate were increased by divercin supplementation (P=0.005, P=0.027, and P=0.002, respectively) and C. perfringens challenge (P=0.034, P=0.053, and P=0.0002, respectively). Divercin supplementation decreased villus heights (P=0.0006) and crypt depths (P=0.044) in noninfected birds, whereas in challenged birds, villus heights (P<0.0001) were increased. In conclusion, the present study demonstrated a very complex response pattern of broilers exposed to C. perfringens challenge and dietary divercin AS7 supplementation, but it indicated that divercin AS7 may partly counterbalance the negative effects associated with C. perfringens.

Dietary divercin modifies gastrointestinal microbiota and improves growth performance in broiler chickens.

1. The aim of the present study was to investigate the effects of dietary administration of a divercin AS7 liquid preparation on broiler chicken performance, nutrient digestibility, counts of lactic acid bacteria (LAB) and coliform bacteria, as well as on the microbial activity in the gastrointestinal tract (GIT) as expressed by digesta pH and concentrations of short-chain fatty acids and lactic acid. 2. A total of 450 1-d-old male Ross 308 chickens were randomly distributed to three dietary treatments, with 15 pens per treatment and 10 birds per pen. The dietary treatments consisted of a positive control (PC) supplemented with 60 mg/kg salinomycin, a negative control (NC) without any additives, and the divercin (DIV) supplemented diet containing 0 x 2 mL/kg of the liquid divercin AS7 preparation. 3. The dietary divercin AS7 supplementation significantly increased body weight gain at 35 d compared to the NC group. Moreover, the pH of crop contents was higher and that of caecal contents lower in birds fed on the divercin supplemented diets. 4. Significantly lower counts of LAB were observed in the crops and caeca of the birds treated with divercin. Further, the divercin supplementation decreased lactic and succinic acid concentrations in the crop and ileum. 5. The present study demonstrates that the use of divercin supplemented diets can influence composition and activity of the microbiota in the broiler chicken GIT even in the lower parts that should otherwise not be targeted due to the peptide structure of the bacteriocin.

Effect of ß -glucanase and xylanase supplementation of barley- and rye-based diets on caecal microbiota of broiler chickens.

1. The aim was to investigate the effect of grain type (barley or rye) and exogenous enzymes (ß-glucanase or xylanase) on the composition of chicken caecal microbiota as examined by classical culturing and molecular techniques (fluorescent in-situ hybridisation (FISH) and terminal-restriction fragment-length polymorphism (T-RFLP)). 2. Plate counting revealed higher total numbers of anaerobic bacteria, lactic acid bacteria and yeasts in caecal contents of birds fed with rye-based diets than in birds fed with barley-based diets. 3. As assessed by FISH analysis, the most abundant bacterial groups in the broiler caeca were Clostridium coccoides-Eubacterium rectale followed by Bacteroides sp., Lactobacillus sp./Enterococcus sp., Bifidobacterium sp. and Enterobacteriaceae. For both cereal types, the enzyme supplementation significantly decreased the relative amount of Enterobacteriaceae. 4. The T-RFLP profiles indicated that the caecal microbiota of birds receiving rye-based diets was more diverse than that of birds fed on barley-based diets. 5. Irrespective of the method applied, the results indicate that the cereal type as well as the exogenous enzyme supplementation influence the microbiota in broiler chicken caeca, and may have the effect of reducing potentially pathogenic Enterobacteriaceae populations.

Influence of dietary peas and organic acids and probiotic supplementation on performance and caecal microbial ecology of broiler chickens.

1. The effect of dietary pea and addition of organic acid blend (OA) or probiotic (Pro) on performance and caecal microbial ecology of broiler chickens was studied. 2. A growth trial was conducted with 160 Ross 308 female broilers from d 1 to 35 of age. There were 8 treatment groups based on either control (S) or white pea (P). Both S and P were supplemented with OA (Galliacid - fumaric acid, calcium formate, calcium propionate and potassium sorbate coated with plant triglycerides, Vetagro) and or with Pro (LABYuc-Probio - lactic acid bacteria, Saccharomyces cerevisiae and Yucca schidigeri extract, Mifarmex GmbH). 3. Inclusion of peas in the diet increased feed intake and decreased gain:feed ratio in comparison to the control diet. Neither probiotic nor OA supplementations affected broiler performance. 4. The caecal microbiota was characterised in 37-d-old birds by fluorescent in situ hybridisation (FISH) and terminal-restriction fragment length polymorphism (T-RFLP). Total bacterial counts in caecal contents were slightly higher for birds fed the pea diets, but were not affected by OA or Pro supplements. 5. Neither pea nor Pro affected the Lactobacillus/Enterococcus and Streptococcus/Lactococcus counts in caecal contents, whereas OA supplementation slightly increased the Lactobacillus/Enterococcus counts. The composition of the Lactobacillus/Enterococcus population was altered by inclusion of peas as revealed by the T-RFLP patterns. 6. The DNA fingerprint further suggested that the caecal microbiota was dominated by the lactic acid bacterium Streptococcus alactolyticus. 7. In ileal contents, the concentration of short-chain fatty acids (SCFA) was decreased only by Pro supplementation. In caecal contents, the SCFA concentration was higher for birds fed on the pea diets, and increased significantly with Pro supplementation 8. In conclusion, the results indicate that the use of pea and probiotics in broiler feed may stimulate the caecal commensal microbiota (growth and/or activity) to some extent and hence prevent establishment of pathogenic and zoonotic enterobacteria in these segments of the gut.

Fermented feed for laying hens: effects on egg production, egg quality, plumage condition and composition and activity of the intestinal microflora.

1. An experiment with a total of 480 hens (Babcock) was carried out from 16 to 38 weeks of age to evaluate the suitability of wet fermented feed (feed water ratio, 1:1.2-1:1.4) for layers, taking aspects of nutrition and gastrointestinal health into consideration. The production performance, egg shell quality, plumage condition, litter dry matter (DM) content, as well as the composition and activity of the intestinal microbial flora were analysed. 2. Fermented feed was characterised by a high concentration of lactic acid (160-250 mmol/kg feed) and a moderate level of acetic acid (20-30 mmol/kg feed), high numbers of lactic acid bacteria (log 9-10 CFU/g feed) and a pH of approximately 4.5. Feed fermentation reduced the concentration of dietary sugar from 32.1 to 7.3 g/kg DM and the phytate bound phosphorus from 2.7 to 1.9 g/kg DM. 3. Fermented feed seemed to loose attractiveness for the birds quite rapidly, resulting in a more aggressive behaviour and a poorer plumage condition than in birds given dry feed. The use of fermented feed reduced the litter DM content. 4. During the experimental period, the body weight gain of hens receiving fermented feed was 80 g higher than of hens fed the dry mash. Presumably because of an extended adaptation time to the feed, the onset of lay occurred later when hens were fed on fermented feed, resulting in non-significantly reduced total egg production (75 vs. 82%). 5. There was no significant difference between groups with respect to the total egg mass production (g/d/hen, 42 and 45 for fermented feed and dry mash, respectively). Throughout the experimental period, the feed DM intake of hens fed with fermented feed was lower than that of hens receiving the dry mash (110 vs. 125 g). From week 26 to 37, fermented feed improved the feed conversion as compared with the dry mash (g feed DM/g egg mass, 2.28 vs. 2.53). 6. The use of fermented feed increased egg weight in the period from 34 to 37 weeks (61.4 vs. 60.0) and increased shell weight (g/100 g egg weight, 10.2 vs. 9.9) and shell stiffness (N/mm, 161 vs. 150) of eggs collected at 37 weeks. 7. The feeding of fermented feed increased intestinal health by acidification of the upper digestive tract, forming a natural barrier towards infection with acid sensitive pathogens, e.g. E. coli, Salmonella and Campylobacter. 8. It was concluded that fermented wet feed offers potential benefits for health and nutrition, but may become suitable for layers only after the practical problems related to this feeding form have been overcome. However, an early adaptation of the birds during the rearing period seems to be necessary.

Effect of feeding silages or carrots as supplements to laying hens on production performance, nutrient digestibility, gut structure, gut microflora and feather pecking behaviour.

1. An experiment was carried out to examine the suitability of using maize silage, barley-pea silage and carrots as foraging materials for egg-laying hens. Production performance, nutrient digestibility, gastrointestinal characteristics, including the composition of the intestinal microflora as well as feather pecking behaviour were the outcome variables. 2. The protein content of the foraging material (g/kg DM) was on average 69 g in carrots, 94 g in maize silage and 125 g in barley-pea silage. The starch content was highest in the maize silage (312 g/kg DM), and the content of non-starch polysaccharides (NSP) varied from 196 to 390 g/kg, being lowest in carrots. Sugars were just traceable in the silages, whereas carrots contained on average 496 g/kg DM. 3. Egg production was highest in hens fed either carrots or maize silage, whereas hens fed barley-pea silage produced less (219 vs. 208). Although the consumption of foraging material was high (33, 35 and 48% of the total feed intake on 'as fed' basis for maize silage, barley-pea silage and carrots, respectively) only a minor effect on nitrogen corrected apparent metabolisable energy (AME(n)) and apparent digestibility was seen. At 53 weeks of age, hens fed maize silage had AME(n) and apparent digestibility values close to the control group (12.61 and 12.82, respectively), whereas access to barley-pea silage and carrots resulted in slightly lower values (12.36 and 12.42, respectively). Mortality was reduced dramatically in the three groups given supplements (0.5 to 2.5%) compared to the control group (15.2%). 4. Hens receiving silage had greater relative gizzard weights than the control or carrot-fed groups. At 53 weeks of age, the gizzard-content pH of hens receiving silage was about 0.7 to 0.9 units lower than that of the control or carrot-fed hens. Hens fed both types of silage had higher concentrations of lactic acid (15.6 vs. 3.2 micromoles/g) and acetic acid (3.6 vs. 6.1 micromoles/g) in the gizzard contents than the other two groups. The dietary supplements had a minor effect on the composition of the intestinal microflora of the hens. 5. Access to all three types of supplements decreased damaging pecking in general (to feathers as well as skin/cloaca), reduced severe feather pecking behaviour and improved the quality of the plumage at 54 weeks of age. 6. In conclusion, access to different types of foraging material such as silages and carrots improved animal welfare.

Microbial community composition of the ileum and cecum of broiler chickens as revealed by molecular and culture-based techniques.

The microbial communities of the ileum and cecum of broiler chickens from a conventional and an organic farm were investigated using conventional culture techniques as well as cloning and sequencing of 16S rRNA genes. Eighty-five percent of the 557 cloned sequences were <97% related to known cultured species. The chicken ileum was dominated by lactobacilli, whereas the cecum harbored a more diverse microbial community. The cecum was dominated by a large group of bacteria with hitherto no close cultured relatives but most closely related to Faecalibacterium prausnitzii. Approximately 49 and 20% of the cecal clones belonged to this cluster in conventional and organic broiler chickens, respectively. We were, however, able to recover a number of these phylotypes by cultivation, and the isolates were shown to be butyric acid producers. The investigation was a descriptive rather than a comparative study of 2 different rearing systems; however, several differences were observed. For instance, Clostridium perfringens was found in significantly higher numbers in the birds from the organic farm compared with the conventional broilers, probably due to the addition of salinomycin to the conventional feed. In the ileum, the abundance of the different Lactobacillus species differed between the 2 broiler types. The culture-based and culture-independent techniques complemented each other well. Strengths and limitations of the different methods are discussed.

The effect of beta-glucanase supplementation of barley- and oat-based diets on growth performance and fermentation in broiler chicken gastrointestinal tract.

1. The aim of the present study was to investigate whether grain type (barley or oats) and ss-glucanase inclusion influence the performance and the gastrointestinal ecosystem of broiler chickens, taking the concentrations of short-chain fatty acids and lactic acid, pH, ileal viscosity, and the weight of the caeca and liver into consideration. 2. The inclusion of beta-glucanase in the oat-based diet improved body weight gains. Enzyme supplementation of barley-based diets improved feed conversion efficiency and reduced intestinal viscosity. 3. Irrespective of the type of cereal, beta-glucanase supplementation increased the lactic acid concentration and lowered the pH of the crop contents. No such changes in fermentation were observed in the contents of the gizzard and ileum. 4. Larger amounts of total dietary fibre and its fractions (arabinoxylans and beta-glucans) in oats decreased the weight of the caeca. 5. Molar ratios of acetate, propionate and butyrate in the caecal chyme were affected by cereal type but not by enzyme supplementation. The barley-based diet increased the butyrate:propionate ratio but the opposite effect was observed with the oat-based diet.

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.

Influence of whole wheat and xylanase on broiler performance and microbial composition and activity in the digestive tract.

An experiment was carried out to study the effect of different forms of wheat (airtight silo stored whole wheat, conventionally stored whole wheat, and ground wheat included in pellets) and dietary xylanase addition on production results and gastrointestinal characteristics of broiler chickens. Ileal viscosity, pancreatic digestive enzyme activities, and the composition and activity of the intestinal microflora were considered as response parameters. Differences between the 2 types of whole wheat with respect to the various measured parameters were marginal, whereas distinct differences were found between pellet-fed birds and birds receiving whole wheat. Whole wheat feeding improved feed conversion ratio and reduced water consumption (P < 0.001). Compared with pellets, whole wheat increased the relative weight of pancreas and gizzard and the dry matter concentration of gizzard content (P < 0.001). Whole wheat feeding reduced the pH in the gizzard contents (P < 0.01) and increased ileal viscosity. The addition of xylanase reduced ileal viscosity in birds receiving whole wheat to the same level as in pellet-fed birds. Whole wheat feeding resulted in lower activities of amylase in pancreatic tissue (P = 0.054), whereas xylanase addition increased chymotrypsin (P = 0.030) and lipase activities (P = 0.052). Whole wheat feeding resulted in lower intestinal numbers of lactose-negative enterobacteria (P < 0.05) and tended to reduce the ileal and cecal numbers of Clostridium perfringens (P < or = 0.08). It is concluded that whole wheat feeding stimulates gizzard function, which in turn prevents potentially pathogenic bacteria from entering the intestinal tract.

Infection models for Salmonella typhimurium DT110 in day-old and 14-day-old broiler chickens kept in isolators.

A series of experiments was undertaken to investigate the infection dynamics of various doses of S. typhimurium in day-old and 14-day-old broiler chickens kept in isolators. The infections were followed quantitatively in ceca and ileum by enumerating the colony forming units (cfu) of the challenge strain. It was found that the inoculation of 10(7) cfu of S. typhimurium to day-old chickens established stable cecal infection in all the animals for 35 days. For 14-day-old chickens, stable and lasting infections were seen with inoculation of 10(9) cfu. Lower doses yielded more variable results, and the bacteria were rapidly eliminated from most birds, especially in 14-day-old inoculated chickens. Salmonella was found in spleen and liver 2-3 days postinoculation. Salmonella was cleared from both organs or reduced to very low numbers within 3 weeks.

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.

Exocrine pancreatic secretion is stimulated in piglets fed fish oil compared with those fed coconut oil or lard.

An experiment was conducted to study the effect of feeding diets containing fat sources with different fatty acid composition (fish oil, coconut oil or lard, 10 g/100 g diet) on exocrine pancreatic secretion in piglets after weaning. A total of 16 barrows were weaned at 4 wk of age; 3 d later, they were surgically fitted with a catheter in the pancreatic duct for continuous collection of pancreatic juice. Collections of pancreatic juice were made every other day starting 4 d postsurgically. Piglets fed the fish oil diet secreted a significantly greater volume of pancreatic juice than piglets fed the coconut oil or lard diets. The output [U/(h. kg(0.75))] of lipase was higher in piglets fed fish oil than in piglets fed lard or coconut oil. The output of colipase was greater in piglets fed fish oil and coconut oil than in those fed lard. The dietary treatments did not affect the output of carboxylester hydrolase. The output of trypsin was significantly lower in piglets fed lard than in piglets fed fish oil or coconut oil diets and the output of carboxypeptidase B was greater in those fed the fish oil diet. Protein, chymotrypsin, carboxypeptidase A, elastase and amylase outputs did not differ among the dietary treatment groups. The apparent digestibilities of nutrients and energy were measured in feces and did not differ among groups. Thus, the greater output of lipase in fish oil-fed piglets did not result in a greater digestibility of fat in this diet.

Effect of zinc bacitracin and salinomycin on intestinal microflora and performance of broilers.

A feeding experiment was carried out over 42 d with four groups of broiler chickens fed experimental diets formulated to provide no supplementation, 20 mg zinc bacitracin, 60 mg salinomycin, or both feed additives in combination. During the fifth week of the experiment, four chickens from each pen were killed, and the contents of gizzard, duodenum, jejunum, ileum, ceca, and rectum were separately collected and pooled. In all intestinal segments, the pH and the concentration of lactic acid were measured, and the numbers of anaerobic bacteria, coliforms, lactic acid bacteria, lactobacilli, enterococci, and Clostridium perfringens were counted. In homogenates of pancreas obtained from four animals, the activities of amylase, lipase, trypsin, and chymotrypsin were measured. A significant growth-promoting effect was observed in the group receiving zinc bacitracin in combination with salinomycin. Zinc bacitracin significantly reduced the number of coliform bacteria in the ileum and increased the activities of amylase and lipase in pancreas homogenates. Supplementation with salinomycin and zinc bacitracin, alone or in combination, resulted in significantly lower counts of C. perfringens as well as Lactobacillus salivarius, which was a dominant lactic acid bacterium found in broiler intestinal contents. High numbers of these lactobacilli may play a role in broiler growth depression related to competition in nutrient uptake or impaired fat absorption due to bile acid deconjugation.