Campylobacter jejuni colonization promotes the translocation of Escherichia coli to extra-intestinal organs and disturbs the short-chain fatty acids profiles in the chicken gut.

For a long time Campylobacter was only considered as a commensal microorganism in avian hosts restricted to the ceca, without any pathogenic features. The precise reasons for the symptomless chicken carriers are still unknown, but investigations of the gastrointestinal ecology of broiler chickens may improve our understanding of the microbial interactions with the host. Therefore, the current studies were conducted to investigate the effects of Campylobacter jejuni colonization on Escherichia coli translocation and on the metabolic end products (short-chain fatty acids, SCFAs). Following oral infection of 14 day old broiler chickens with 1 × 10(8) CFU of Campylobacter jejuni NCTC 12744 in two independent animal trials, it was found that C. jejuni heavily colonized the intestine and disseminate to extra-intestinal organs. Moreover, in both animal trials, the findings revealed that C. jejuni promoted the translocation of E. coli with a higher number encountered in the spleen and liver at 14 days post infection (dpi). In addition, Campylobacter affected the microbial fermentation in the gastrointestinal tract of broilers by reducing the amount of propionate, isovalerate, and isobutyrate in the cecal digesta of the infected birds at 2 dpi and, at 7 and 14 dpi, butyrate, isobutyrate, and isovalerate were also decreased. However, in the jejunum, the C. jejuni infection lowered only butyrate concentrations at 14 dpi. These data indicated that C. jejuni may utilize SCFAs as carbon sources to promote its colonization in the chicken gut, suggesting that Campylobacter cannot only alter gut colonization dynamics but might also influence physiological processes due to altered microbial metabolite profiles.Finally, the results demonstrated that C. jejuni can cross the intestinal epithelial barrier and facilitates the translocation of Campylobacter itself as well as of other enteric microorganisms such as E. coli to extra-intestinal organs of infected birds. Altogether, our findings suggest that the Campylobacter carrier state in chicken is characterised by multiple changes in the intestinal barrier function, which supports multiplication and survival within the host.

Deoxynivalenol in chicken feed alters the vaccinal immune response and clinical biochemical serum parameters but not the intestinal and carcass characteristics.

This study was conducted to investigate the impacts of deoxynivalenol (DON) feeding either alone or in combination with a microbial feed additive (MFA) on the immune response to a viral vaccine and serum clinical chemical parameters. Forty 1-day-old boiler chicks were weighed and randomly divided into four groups, 10 birds in each group: (i) control group fed with basal diet; (ii) DON group fed with basal diet artificially contaminated with 10 mg DON/kg feed; (iii) DON + MFA group fed with basal diet contaminated with 10 mg DON/kg feed and supplemented with 2.5 kg of MFA/ton feed; and (iv) MFA group fed with basal diet supplemented with 2.5 kg of MFA/ton feed. At 35 days of age, birds were slaughtered and blood was collected for investigating the antibody titre against infectious bronchitis virus (IBV) and clinical chemical parameters. The results showed that DON reduced (p = 0.032) the titre against IBV, decreased (p = 0.005) the level of alanine transaminase (ALT) (4.2 ± 0.5 U/l) compared with control birds (6.4 ± 0.5 U/l), increased (p = 0.002) the serum cholesterol concentration (144 ± 6 mg/dl) compared with their control counterparts (123 ± 5 mg/dl) and increased (p = 0.074) the amount of circulating triglycerides (62.25 ± 7.50 mg/dl) compared with controls (39.55 ± 4.74). These results indicate that dietary DON altered the humoral immune response to viral vaccine and affected the serum clinical biochemistry. However, DON in combination with MFA did not affect serum IBV titre. Taken together, DON in the feed of broilers produced an impairment of the success of IBV vaccine and affected the health of birds.

Composition of diet modifies colonization dynamics of Campylobacter jejuni in broiler chickens.

AIMS: To evaluate the impact of diet composition on colonization dynamics of Camp. jejuni and on related physiological parameters in the chicken intestine. METHODS AND RESULTS: A total of 54 1-day-old Ross 308 broiler chicks were randomly divided into three isocaloric and isonitrogenous dietary groups: maize-based (MB), wheat-based (WB) diet and wheat-based diet with NSP-degrading enzyme supplementation (WBES). Chickens were orally infected with 10(8)  CFU Camp. jejuni on day 14, and samples (n = 6) were collected on 7, 14 and 21 days postinfection (DPI), respectively. Colony forming units of Camp. jejuni of caecum and jejunum, short-chain fatty acid (SCFA) concentrations, pH values of the caecum, jejunal histomorphology and viscosity of jejunal chymus were measured. In case of WBES diet, lower Camp. jejuni colonization 14 DPI, higher jejunal viscosity, higher total SCFA concentrations in the caecum and enhanced jejunal histomorphology were observed compared to those measured in chickens fed MB diet. CONCLUSIONS: The WBES diet altered Camp. jejuni colonization dynamics in the chicken intestine which resulted by higher SCFA concentrations in the caecum and by the change of gut morphology. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study proves that diet composition can modify Camp. jejuni colonization depending on sampling time point postinfection.

Mechanisms underlying the inhibitory effect of the feed contaminant deoxynivalenol on glucose absorption in broiler chickens.

Deoxynivalenol (DON), a major contaminant of cereals and grains, is of public health concern worldwide and has been shown to reduce the electrogenic transport of glucose. However, the full effects of Fusarium mycotoxins on nutrient absorption are still not clear. The aim of this study was to investigate whether decreased nutrient absorption was due to specific effects on transporter trafficking in the intestine and whether inhibition of phosphoinositol-3-kinase (PI-3-kinase) affected the electrogenic jejunal transport of glucose. Jejunal mucosa of 6-week-old broiler chickens were mounted in Ussing chambers and treated with DON, wortmannin (a specific inhibitor of PI-3-kinase), DON + wortmannin, phlorizin and cytochalasin B. DON was found to decrease the short-circuit current (Isc) after glucose addition. A similar decline in Isc after glucose addition was observed following pre-application of wortmannin, or phlorizin (Na(+)/glucose co-transporter, SGLT1 inhibitor). The results indicate that DON decreased glucose absorption in the absence of wortmannin or phlorizin but had no additional effect on glucose absorption in their presence. Glucose transport was not affected by cytochalasin B (facilitative glucose transporter, GLUT2 inhibitor). The study provides evidence that the suppressive effect of DON on the electrogenic transport of glucose may be due to an inhibitory activity of the PI3 kinase pathway and intestinal SGLT1. Furthermore, the effect of cytochalasin B on glucose transport in chicken tissues differs from that in mammals.

Intestinal epithelial responses to Salmonella enterica serovar Enteritidis: effects on intestinal permeability and ion transport.

Salmonella infection of chickens that leads to potential human foodborne salmonellosis continues to be a major concern. Chickens serve as carriers but, in contrast to humans, rarely show any clinical signs including diarrhea. The present investigations aimed to elucidate whether the absence of diarrhea during acute Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) infection may be linked to specific changes in the electrophysiological properties of the chicken gut. Immediately after slaughter, intestinal pieces of the mid-jejunum and cecum of either commercial broiler or specific pathogen-free (SPF) chickens were mounted in Ussing chambers in 2 separate experimental series. Living Salmonella Enteritidis (3 × 10(9)) or Salmonella Enteritidis endotoxin (20 mg/L), or both, were added to the mucosal side for 1 h. In both experimental series, the Salmonella infection decreased the trans-epithelial ion conductance G(t) (P < 0.05). In the jejunum of SPF chickens, there was also a marked decrease in net charge transfer across the epithelium, evidenced by decreased short-circuit current (I(sc), P < 0.05). Interestingly, the mucosal application of Salmonella endotoxin to the epithelial preparations from jejunum and cecum of SPF chicken had an effect similar to living bacteria. However, the endotoxin had no additional effect on the intestinal function in the presence of bacteria. The decreasing effect of Salmonella and or its endotoxin on G(t) could be partly reversed by serosal addition of histamine. To our knowledge, this is the first study to address the functional response of native intestinal epithelium of chicken to an in vitro Salmonella infection. For the first time, it can be reported that intestinal ion permeability of chicken decreases acutely by the presence of Salmonella. This type of response could counteract ion and fluid secretion and may thus, at least in part, explain why chickens do not develop overt diarrhea after Salmonella infection.

Evaluating the efficacy of an avian-specific probiotic to reduce the colonization of Campylobacter jejuni in broiler chickens.

Campylobacteriosis is the most frequent zoonotic disease in humans worldwide, and the contaminated poultry meat by Campylobacter jejuni can be considered one of the important sources of enteric infections in humans. The use of probiotics, which can help to improve the natural defense of animals against pathogenic bacteria, is an alternative and effective approach to antibiotic administration for livestock to reduce bacterial contamination. In vitro experiments showed that Enterococcus faecium, Pediococcus acidilactici, Lactobacillus salivarius, and Lactobacillus reuteri isolated from healthy chicken gut inhibited the growth of C. jejuni. To demonstrate this effect in vivo, 1-d-old broiler chicks received 2 mg/bird per day of a multispecies probiotic product via the drinking water. Controls received no probiotic treatment, and all chicks were infected with C. jejuni orally. Results showed that the cecal colonization by C. jejuni was significantly reduced by probiotic treatment at both 8 and 15 d postchallenge. To confirm this effect, in a second in vivo experiment, 1-d-old broiler chicks received the same dose of the same probiotic via the drinking water and controls received no probiotic, and all chicks were infected with C. jejuni orally. Similarly, probiotic treatment reduced (P=0.001) cecal colonization by C. jejuni at both 8 and 15 d postchallenge. The results of our in vivo experiments conclude that probiotic administration reduced the colonization of C. jejuni in broiler chickens.

Ameliorative effect of a microbial feed additive on infectious bronchitis virus antibody titer and stress index in broiler chicks fed deoxynivalenol.

Although acute mycotoxicoses are rare in poultry production, chronic exposure to low levels of mycotoxins is responsible for reduced productivity and increased susceptibility to infectious diseases. Deoxynivalenol (DON) is known to modulate immune function, but only a few studies have investigated the effect of DON on the vaccinal immune response. In addition, the effects of Mycofix select (Biomin GmbH, Herzogenburg, Austria) supplementation to DON-contaminated broiler diets have not yet been demonstrated. Therefore, an experiment with 1-d-old male broilers (Ross 308) was carried out to examine the effects of feeding DON-contaminated low-protein grower diets on performance, serum biochemical parameters, lymphoid organ weight, and antibody titers to infectious bronchitis vaccination in serum and to evaluate the effects of Mycofix select dietary supplementation in either the presence or absence of DON in broilers. In total, thirty-two 1-d-old broiler chicks were randomly assigned to 1 of the 4 dietary treatments for 5 wk. The dietary treatments were 1) control; 2) artificially contaminated diets with 10 mg of DON/kg of diet; 3) DON-contaminated diets supplemented with Mycofix select; and 4) control diet supplemented with Mycofix select. Feeding of contaminated diets decreased (P = 0.000) the feed intake, BW (P = 0.001), BW gain (P = 0.044), and feed efficiency during the grower phase. Deoxynivalenol affected the blood biochemistry, whereas plasma total protein and uric acid concentrations in birds fed contaminated grains were decreased compared with those of the controls. Moreover, in birds fed contaminated feeds, there was a tendency to reduce triglycerides in the plasma (P = 0.090), suggesting that DON in the diets affected protein and lipid metabolism in broiler chickens. The feeding of contaminated diets altered the immune response in broilers by reducing the total lymphocyte count. Similarly, the antibody response against infectious bronchitis vaccination antigens was decreased (P = 0.003) after feeding contaminated diets, compared with the controls. Moreover, contamination of the broiler diet with DON increased the heteropil:lymphocyte ratio (stress index), suggesting that DON elevated the physiological stress responses of broilers. However, feeding of DON-containing diets did not alter the other plasma constituents, including activities of enzymes. Mycofix select addition to the DON-contaminated feed led to normal immunological and physiological functions in broilers that were comparable with those of the control group, indicating that the addition of the additive to the DON-contaminated feed of the broilers effectively alleviated the alterations caused by DON. It was concluded that broiler performance and some blood and immunological parameters were adversely affected by feeding diets contaminated with the Fusarium mycotoxin DON. However, the dietary Mycofix select supplementation as a detoxifying agent was successful in overcoming the mycotoxin-related effects.

Genotoxic effects of deoxynivalenol in broiler chickens fed low-protein feeds.

Deoxynivalenol (DON) is one of the most abundant and important trichothecenes in food and feed, and it is a significant contaminant due to its frequent occurrence at toxicologically relevant concentrations worldwide. Deoxynivalenol has negative influences on the health and performance of chicks. However, there is little information available regarding the effect of DON on DNA fragmentation in blood lymphocytes. In addition, the effects of Mycofix select (Biomin GmbH, Herzogenburg, Austria) supplementation to DON-contaminated broiler diets on lymphocyte DNA have not yet been demonstrated. Therefore, the aim of the present study was to establish the effect of DON on lipid peroxidation and lymphocyte DNA fragmentation in broilers and to evaluate the potential of Mycofix select in the prevention of toxin-mediated changes. Thirty-two 1-d-old (Ross 308 male) broiler chicks were randomly divided into 4 groups. The control group was fed a noncontaminated diet, and a second group was fed the same diet but supplemented with Mycofix select (0.25%). A third group of broilers was fed a diet artificially contaminated with 10 mg of feed-grade DON/kg of diet, and a fourth group was fed a DON-contaminated diet supplemented with Mycofix select. At the end of the feeding trial, blood was collected and the degree of lymphocyte DNA damage was measured in the plasma by comet assay. Deoxynivalenol increased (P = 0.016) the amount of DNA damage in chicken lymphocytes by 46.8%. Mycofix select protected lymphocyte DNA from the DON effects. To our knowledge, these are the first data on genotoxic effects of a moderate dose of DON on chicken lymphocytes. However, the thiobarbituric acid reactive substances level in liver and liver enzyme activity did not differ among the groups. In conclusion, the present study demonstrated that the diets contaminated with the mycotoxin DON at moderate levels in combination with low-protein feed are able to induce lymphocyte DNA damage in chickens. Supplementation with Mycofix select protected lymphocyte DNA and it was beneficial for maintaining the lymphocyte DNA integrity.

Cytotoxicity and metabolic stress induced by deoxynivalenol in the porcine intestinal IPEC-J2 cell line.

The digestive tract is a target for the Fusarium toxin deoxynivalenol (DON), a major cereal grain contaminant of animal and public health concern. Toxic effects of DON range from diarrhoea, vomiting and gastrointestinal inflammation to necrosis of several tissues. Following ingestion of contaminated food or feed, intestinal epithelial cells are exposed to a high concentration of ingested DON, potentially affecting intestinal functions. Pigs are considered to be the species most sensitive to DON toxicity. However, only few studies directly evaluated DON effects on porcine intestinal epithelial cells. Therefore, we used the porcine intestinal cell line (IPEC-J2) to assess short-term effects of DON on functional characteristics of the intestinal epithelial cells. The cytotoxic effect of DON on IPEC-J2 cells was evaluated by measuring the count of living cells and the activity of lactate dehydrogenase (LDH) released in the culture media at a DON concentration range from 0, 0.5, 2.5 and 10 µm. We demonstrated that DON at concentrations of 2.5 and 10 µm decreased significantly (p < 0.001) the cell count in a dose-dependent manner. At a concentration of 10 µm, DON caused cell damage, including rounding of cells, autolysis and cell loss from the monolayer. The mycotoxin, DON, increased LDH release into the culture medium compared with the control value. The alterations of LDH showed a good agreement with the decrease in cell count. Deoxynivalenol decreased the l-lactate concentration in the fluid supernatant of IPEC-J2 cells at 2.5 µm (p < 0.05) with a maximal effect at 10 µm of DON. To determine whether the altered lactate production may be linked to alterations of energy balance, we measured cellular ATP levels in IPEC-J2 cells. A significant decrease in ATP levels was seen at 48 h in a dose-dependent manner. It could be demonstrated that DON has a distinct cytotoxic effect on IPEC-J2 cells.

Evaluation of the chicory inulin efficacy on ameliorating the intestinal morphology and modulating the intestinal electrophysiological properties in broiler chickens.

Chicory (Cichorium intybus) belongs to plants of the Compositae family accumulating energy in the form of inulin fructan. Chicory, a prebiotic, is a fermentable oligosaccharide and oligofructose that may affect the intestinal mucosal architecture and the electrophysiological parameters. Therefore, this study was conducted to evaluate the effectiveness of adding chicory fructans in feed on the intestinal morphology and electrogenic transport of glucose in broilers. Four hundred, 1-day-old broiler chicks were randomly divided into two groups (200 birds per group) for 5 weeks. The dietary treatments were (i) control, (ii) basal diets supplemented with the dried, ground chicory pulp containing inulin (1 kg of chicory/ton of the starter and grower diets). In duodenum, dietary chicory increased the villus height and villus width and villus height to crypt depth ratio (p< 0.05), but the duodenal crypt depth remained unaffected (p > 0.05). However, in jejunum, the villus height, crypt depth and villus height to crypt depth ratio were decreased by dietary chicory compared with control birds (p < 0.05). In ileum, the villus height and villus crypt depth was decreased by dietary chicory supplementation compared with control (p< 0.05), but, the villus height to crypt depth ratio was increased (p< 0.05). Moreover, dietary chicory relatively affected the electrophysiological parameters of the intestine but did not reach significance. The amount of ΔIsc after d-glucose addition to the jejunal mucosa was numerically higher for chicory fed birds (19 µA/cm(2) ) than control birds (10 µA/cm(2) ). The percentage of increase in the Isc after d-glucose addition (ΔIsc %) was higher for chicory group upto (90%) of the control group. In colon, the actual Isc value and Isc after d-glucose addition was numerically higher for chicory fed birds than control birds (p> 0.05). Moreover, the conductance of jejunal and colonic tissues after d-glucose addition remained unaffected by the dietary chicory. In conclusion, addition of chicory to broilers diet increased the duodenal villus height, villus width and villus height to crypt depth ratio and decreased the villus height and crypt depth in both jejenum and ileum. Furthermore, dietary chicory relatively modified the small intestinal electrogenic transport of glucose in broilers.

In vitro aflatoxin B(1) exposure decreases response to carbamylcholine in the jejunal epithelium of broilers.

The study was conducted to evaluate if aflatoxin B(1) (AFB(1)) has the capacity to affect the electrophysiological variables and active glucose uptake in jejunal epithelium of chicken. For this purpose, intestinal segments from the middle jejunum of broilers (35 to 39 d old) were incubated in Ussing chambers in the presence of 0 (vehicle control), 1.25, 2.50, and 3.75 microg of AFB(1)/mL of buffer. After 40 and 60 min of incubation with AFB(1), d-glucose (20 mmol/L) and carbamylcholine (200 micromol/L; an analog of acetylcholine and inducer of apical Cl(-) secretion) were respectively added to the incubation medium. Addition of 3.75 microg of AFB(1) caused an increase (P < 0.04) in short-circuit current (I(sc)) and transmural potential difference (V(t)) between 12 to 27 min postexposure as compared with the control. Glucose-induced DeltaI(sc) and percentage of DeltaV(t) were reduced (P < 0.04) at 2.5 and 3.75 microg of AFB(1)/mL, respectively, as compared with the control. The carbamylcholine-induced DeltaI(sc) and DeltaV(t) were both lower (P < 0.05) at 3.75 microg of AFB(1)/mL as compared with the control (-0.05 microA/cm(2), 0.1 mV vs. 1.1 microA/cm(2), and 0.6 mV, respectively). These observations indicate that acute exposure to AFB(1) may increase apical anion secretion in the jejunal epithelium of chicken. The negative effect of this increased anion secretion on active glucose uptake was, however, not prominent and may be considered as moderate or progressive in nature.

Effect of addition of a probiotic micro-organism to broiler diet on intestinal mucosal architecture and electrophysiological parameters.

Probiotics might be one of the solutions to reduce the effects of the recent ban on antimicrobial growth promoters in feed. However, the mode of action of probiotics still not fully understood. Therefore, evaluating probiotics (microbial feed additives) is essential. Thus the objective of this work was to investigate the efficacy of a new microbial feed additive (Lactobacillus salivarius and Lactobacillus reuteri) in broiler nutrition. The body weight (BW), average daily weight gain was relatively increased by the dietary inclusion of Lactobacillus sp. in broiler diets. Furthermore, the Lactobacillus feed additive influenced the histomorphological measurements of small intestinal villi. The addition of Lactobacillus sp. increased (p < 0.05) the villus height (VH)/crypt depth ratio and the VH was numerically increased in duodenum. The duodenal crypt depth remained unaffected (p > 0.05), while the ileal crypt depth was decreased by dietary supplementation of Lactobacillus sp. compared with the control. At the end of the feeding period, the basal and glucose stimulated short-circuit current (Isc) and electrical tissue conductivity were measured in the isolated gut mucosa to characterize the electrical properties of the gut. The addition of glucose on the mucosal side in Ussing chamber produced a significant increase (p = 0.001) in Isc in both jejunum and colon relative to the basal values in Lactobacillus probiotic group. This increase in Isc for probiotic group in jejunum is equivalent to an increase of about two times that for the basal values, while in the control group is about half fold that for the basal value. In addition, the DeltaIsc after glucose addition to the large intestine was greater than the DeltaIsc in the small intestine in both control and probiotic group. Moreover in both jejunum and colon, the increase in Isc for birds fed Lactobacillus was higher than their control counterparts (p < or = 0.1). This result suggests that the addition of Lactobacillus sp. to broiler diets increased the glucose transport. Additionally, the results indicated that the conductivity of jejunal and colonic tissues remained unaffected by the dietary inclusion of Lactobacillus and support the concept that this additive enhances the maintenance and function of the epithelial barrier. In conclusion, dietary inclusion of a microbial feed additive (L. salivarius and L. reuteri) slightly increased the growth performance and improved intestinal nutrient absorption which was in association with the intestinal architecture improvement.

Effects of dietary inclusion of probiotic and synbiotic on growth performance, organ weights, and intestinal histomorphology of broiler chickens.

A feeding trial was conducted to investigate the effects of dietary supplementations of synbiotic and probiotic on broiler performance, carcass yield, organs weights, and histomorphological measurements of small intestine. Six hundred 1-d-old broiler chicks were randomly assigned to 1 of 3 dietary treatments for 5 wk. The dietary treatments were 1) control, 2) basal diets supplemented with synbiotic (1 kg of Biomin IMBO/ ton of the starter diets and 0.5 kg/ton of the grower diets), 3) basal diets supplemented with probiotic (1 kg of a homofermentative and a heterofermentative Lacto-bacillus sp./ton of feed). The BW, average daily weight gain, carcass yield percentage, and feed conversion rate were significantly (P < 0.05) increased by the dietary inclusion of the synbiotic compared with the control and probiotic-fed broilers. Moreover, a slight improvement in performance traits was observed in broilers fed the probiotic compared with control birds. The absolute and relative weight of spleen and thymus tended to be greater (P < 0.1) for the probiotic-supplemented group compared with the synbiotic-supplemented group. The relative liver weight was greater (P < 0.05) for probiotic-fed birds compared with synbiotic-fed birds. Additionally, the weight of small intestine was greater for either probiotic- (3.17) or synbiotic-fed birds (3.11) than the controls (2.89). Furthermore, dietary treatments influenced the histomorphological measurements of small intestinal villi. The addition of either probiotic or synbiotic increased (P < 0.05) the villus height:crypt depth ratio and villus height in both duodenum and ileum. The duodenal crypt depth remained unaffected (P > 0.05). However, the ileal crypt depth was decreased by dietary supplementations compared with control. In conclusion, synbiotic or probiotic displayed a greater efficacy as growth promoters for broilers. Furthermore, the dietary supplementations resulted in an increase in the villus height and crypt depth of intestinal mucosa of broilers. The increase in the villus height and villus height:crypt depth ratio was associated with improvement of growth performance for both synbiotic and probiotic. This indicates that the synbiotic and probiotic can be used as a growth promoter in broiler diets and can improve the gut health. These products show promising effects as alternatives for antibiotics as pressure to eliminate growth-promotant antibiotic use increases.

Stability of fear and sociality in two strains of laying hens.

1. This trial studied the effects of strain and age on tonic immobility (TI) duration, emergence time (ET) and social reinstatement time (SRT) in laying hens and investigated the consistency of individual behavioural characteristics over rearing and laying periods and the correlations between these behavioural traits. 2. One hundred chicks from each of ISA Brown (ISA) and Lohmann Tradition (LT) laying hens were reared from one day old in pens. At 3 weeks, birds of each line were divided into 4 groups. Twenty birds in one group of each line were marked individually for repeated testing and the other groups were assigned for single testing to test the habituation effect and possible age effects at a group level. 3. ISA birds had higher overall means for TI duration and latency to leave the start box. ISA also showed longer latency in SRT at week 28 than Lohmanns. TI duration increased from weeks 3 to 10 and then decreased to week 35 in both lines. The latency to explore the test area and to reinstate decreased from weeks 10 to 35. 4. Tonic immobility, exploratory and social reinstatement behaviours were consistent over time in both lines, as revealed by Kendall's W coefficient of concordance. 5. In social test situations, an inter-situational consistency was found, that is, birds emerged quickly from the start box and reinstated quickly with their companion. TI (non-social test) was negatively correlated with ET and SRT. Thus the two lines of laying hens respond differently in social and non-social tests.

Effects of B-trichothecenes on luminal glucose transport across the isolated jejunal epithelium of broiler chickens.

Trichothecenes are closely-related sesquiterpenoids (ring structure) with a 12, 13 epoxy ring and a variable number of hydroxyl, acetyl or other substituents. In chickens, D-glucose and amino acid absorption occurs via carrier-mediated transport. Recently, it has been observed that deoxynivalenol (DON) alters the gut function and impairs glucose and amino acid transport in chickens. The purpose of this work was to determine the effects of different B-trichothecenes [DON, Nivalenol (NIV), 15-Ac-DON and Fusarenon X (FUS X)] on intestinal carrier-mediated sodium co-transport of D-glucose in the small intestine of broiler chickens. Intestinal transport was determined by changes in the short-circuit current (Isc), proportional to ion transmembrane flux, in the middle segment of the jejunum of broilers with the Ussing chamber technique. D-glucose produced an increase of the Isc, and this effect was reverted by different B-trichothecene mycotoxins, indicating that the glucose induced Isc was altered by B-trichothecenes. The addition of glucose after pre-incubation of the tissues with B-trichothecenes had no effect (p > 0.05) on the Isc, suggesting that B-trichothecenes afflicted the Na(+)-D-glucose co-transport. However, FUX had no obvious effect on the measured parameters. It could be concluded from the present study that the glucose co-transporter activity appears to be more sensitive to DON, NIV and 15-Ac-DON suppression than by FUS X in the jejunum of broilers.

Influence of deoxynivalenol on the D-glucose transport across the isolated epithelium of different intestinal segments of laying hens.

Deoxynivalenol (DON) decreases glucose absorption in the proximal jejunum of laying hens in vitro and this effect is apparently mediated by the inhibition of the sodium D-glucose co-transporter. DON could modulate the sugar transport of other intestinal regions of chickens. For this purpose, we have measured the effects of DON on the Na(+) D-glucose co-transporter, by addition of DON after and before a glucose addition in the isolated epithelium from chicken duodenum, jejunum, ileum, caecum and colon by using the Ussing chamber technique in the voltage clamp technique. The data showed in all segments of the gut that the addition of D-glucose on the mucosal side produced an increase in the current (Isc) compared with the basal values, the Isc after glucose addition to the small intestine was greater than the Isc of the large intestine compared with the basal values, specially of the jejunum (p < 0.002), indicating that the jejunum is the segment that is the best prepared for Na(+)-D-glucose co-transport. Further addition of 10 microg DON/ml to the mucosal solution decreased the Isc in all segments and the Isc returned to the basal value, especially in the duodenum and mid jejunum (p < 0.05). In contrast, the addition of 5 mmol D-glucose/l on the mucosal side after incubation of the tissues with DON in all segments had no effect on the Isc (p > 0.05), suggesting that DON previously inhibited the Na(+)D-glucose co-transport. The blocking effects of DON in duodenum and jejunum were greater than the other regions of the gut. It can be concluded that the small intestine of laying hens has the most relevant role in the carrier mediated glucose transport and the large intestine, having non-significant capacity to transport sugars, appears to offer a minor contribution to glucose transport because the surface area is small. The effect of D-glucose on the Isc was reversed by DON in all segments, especially in the duodenum and jejunum, suggesting that DON entirely inhibited Na(+)-D-glucose co-transport. This finding indicates that the inhibition of Na(+) co-transport system in all segments could be an important mode of action for DON toxicity of hens.

In vitro effects of deoxynivalenol on small intestinal D-glucose uptake and absorption of deoxynivalenol across the isolated jejunal epithelium of laying hens.

Deoxynivalenol (DON) is a common mycotoxin contaminant in feedstuffs. It has been shown to cause diverse toxic effects in animals. The aim of the present study was to evaluate the effects of DON on the glucose transport capacity in chickens' jejunum and to investigate the permeation of DON itself by the Ussing chamber technique. Glucose uptake into chicken jejunal epithelia was measured after the addition of 200 mumol/L of (14)C-labeled glucose to the mucosal solution. Glucose uptake under control condition was 3.28 +/- 0.53 nmol/cm(2) x min. The contribution of sodium glucose-linked transporter 1 (SGLT-1) to total glucose uptake was estimated by inhibiting SGLT-1 with phlorizin (100 micromol/L). In the presence of phlorizin, glucose uptake was reduced (P < 0.05) to 1.21 +/- 0.19 nmol/cm(2) x min. Deoxynivalenol decreased (P < 0.05) the glucose uptake in the absence of phlorizin to 1.81 +/- 0.24 nmol/cm(2) x min but had no additional effect on the glucose uptake in the presence of phlorizin (0.97 +/- 0.17 nmol/cm(2) x min). Mucosal-to-serosal permeation of DON was proportional to the initial DON concentration over a concentration range from 1 to 10 mug/mL on the mucosal side. Apparent permeability at 10 microg/mL of DON measured 60 to 90 min after DON application was 1.7 x 10(-05) cm/s. It can be concluded that DON (10 mg/L) decreases glucose uptake almost as efficiently as phlorizin. The similarity between the effects of phlorizin and DON on glucose uptake evidences their common ability to inhibit Na(+)-D-glucose cotransport. In addition to local effects, DON can be absorbed from the jejunum. A predominant part of DON passes across the chicken intestinal epithelium by passive diffusion, which is likely on the paracellular pathway. The results imply that the exposure to DON-contaminated feeds may negatively affect animal health and performance by local (i.e., inhibition of intestinal SGLT-1) and systemic effects.

Clostridium perfringens alpha toxin affects electrophysiological properties of isolated jejunal mucosa of laying hens.

Bacteria that colonize the intestinal tract can invade epithelial cells or produce toxins that cause diarrhoeal diseases. Proliferation of Clostridium perfringens and production of alpha-toxin, a phospholipase C, is the major factor for necrotic enteritis in poultry. However, little is known about the functional importance of luminal alpha-toxin during intestinal infection. The purpose of this study was to investigate the effects of purified alpha toxin of Clostridium perfringens on the electrophysiology of the laying hen's stripped jejunum in Ussing chambers. The effects were investigated in Experiment 1 after toxin addition to the mucosal and serosal side of the tissue, and a second experiment was performed to study the effect of the toxin on sodium-dependent glucose transport. Mucosal exposure of jejunal tissue sheets to 100 units of alpha toxin/L did not elicit electrophysiologic changes. The addition of purified alpha toxin to the serosal side induced a biphasic increase in short-circuit current (ISC) after 15 and 100 min. The magnitude of the increase of ISC of both peaks was similar, but the second phase response lasted longer. The tissue conductivity tended (P = 0.07) to be lower after 2 h of toxin addition compared with basal value when no toxin was added. In the second experiment, adding D-glucose on the mucosal side of the jejunum increased (P < 0.05) the ISC from a baseline value of 42 +/- 28 microA/cm2 to a maximal value of 103 +/- 27 microA/cm2. Preincubation with alpha-toxin almost fully inhibited this stimulation of ISC by D-glucose. The conductance of the tissues was not affected by the toxin addition. These findings indicate that alpha toxin not only causes electrogenic secretion of anions, probably due to the stimulation of chloride secretion, but also diminishes electrogenic Na+/glucose cotransport from the mucosal to serosal side in the small intestine of poultry.

Effect of addition of a probiotic microorganism to broiler diets contaminated with deoxynivalenol on performance and histological alterations of intestinal villi of broiler chickens.

An experiment was conducted to study the effects of deoxynivalenol (DON) on the performance of broilers, organ weights, and intestinal histology and to evaluate the efficacy of a probiotic feed additive (PB, Eubacterium sp.) with the ability to deepoxidize DON. Two hundred seventy-seven 1-d-old broiler chicks were randomly assigned to 1 of the 3 dietary treatments for 6 wk. The dietary treatments were 1) control; 2) artificially contaminated diets with 10 mg of DON/kg of diet; 3) DON-contaminated diets plus probiotic feed additive (DON-PB). The BW and the efficiency of feed utilization were not adversely affected (P > 0.05) by the inclusion of DON in the diets. A slight improvement in feed intake and BW gain over the course of the experiment was observed in broilers fed DON-PB with no change in feed efficiency. The absolute or relative organ weights were not altered (P > 0.05) in broilers fed the diet containing DON compared with controls and the DON-PB group. The absolute liver weights were numerically increased (P < 0.1) for broilers receiving the diet containing DON-PB. There were no significant differences in the absolute and relative weights of the gizzard, duodenum, pancreas, heart, and spleen. However, the absolute and relative weights of the jejunum and cecum were increased for DON-PB-fed broilers compared with the controls and DON group. No pathological lesions were found in the gut of birds fed DON-contaminated diets during the feeding trial, but mild intestinal changes were observed. The DON altered small intestinal morphology, especially in the duodenum and jejunum, where villi were shorter and thinner (P < 0.05). The addition of the eubacteria to the DON-contaminated feed of the broilers effectively alleviated the histological alterations caused by DON and led to comparable villus length as in the control group. In conclusion, diets with DON contamination below levels that induce a negative impact on health and performance could affect small intestinal morphology in broilers. The histological alterations caused by DON were reduced by supplementing the DON-containing diets with PB. This indicates that in case of DON contamination of feedstuffs, the addition of PB would be a proper way to counteract the possible effects caused by this mycotoxin.

Effects of feeding deoxynivalenol contaminated wheat on growth performance, organ weights and histological parameters of the intestine of broiler chickens.

A feeding trial was conducted to evaluate the effects of moderate dietary concentrations of deoxynivalenol (DON) during a 21-day feeding experiment on the performance of broilers. Fifteen 1-day-old broiler chicks were randomly divided into two groups. The control group was fed non-contaminated diet. Another group of broilers was fed a diet naturally contaminated with 5 mg DON/kg diet. Deoxynivalenol had no effect (p > 0.05) on feed consumption, feed conversion, body-weight gain, live body weight or mortality. The absolute and relative weight of the organs (gizzard, pancreas, heart, spleen, colon and caecum) were not altered by the dietary inclusion of DON contaminated grain. However, both the absolute and relative weight of small intestine was decreased (p < 0.01) in DON fed broilers compared to the controls. No gross lesions were detected in any of the organs of birds fed contaminated wheat during the feeding trial. The microscopic examination revealed that, the height and the width of villi in duodenum decreased (p < 0.05) in birds fed DON contaminated wheat compared to controls. On the other hand the height and the width of jejunum villi were not affected (p > 0.05). This study indicates that feeding DON for 21 days to broiler chickens at a concentration of up to 5 mg/kg of diet influenced the weight of the small intestine as well as intestinal histology, especially the duodenum, as evidenced by shorter and thinner villi. In conclusion, diets with DON contamination below levels that induce negative impact on health and performance could affect small intestinal morphology in broilers.