Comparison between effects of standard feed and whole wheat supplemented diet on experimental Eimeria tenella and Eimeria maxima infections in broiler chickens

Fas is a surface receptor that can transmit signals for apoptosis. Using retroviral cDNA library-based functional cloning we identified a gene, toso, that blocks Fas-mediated apoptosis. Toso expression was confined to lymphoid cells and was enhanced after cell-specific activation processes in T cells. Toso appeared limited to inhibition of apoptosis mediated by members of the TNF receptor family and was capable of inhibiting T cell self-killing induced by TCR activation processes that up-regulate Fas ligand. We mapped the effect of Toso to inhibition of caspase-8 processing, the most upstream caspase activity in Fas-mediated signaling, potentially through activation of cFLIP. Toso therefore serves as a novel regulator of Fas-mediated apoptosis and may act as a regulator of cell fate in T cells and other hematopoietic lineages.     

Protective oral immunization of chickens against Eimeria tenella with sporozoite surface antigens

Antigens were extracted from the surface of Eimeria tenella sporozoites with a solution containing Triton X 100 (1%), sodium dodecyl sulphate (0.5%) Na deoxycholate (1%) and EDTA (1 mM). After removal of the detergents, these surface antigen preparations conferred an immunity that protected chickens against a subsequent infection (10(4) sporulated oocysts). The best results were obtained after two 250 micrograms injections of Al(OH)3 adsorbed antigens (oocyst output per g caecal material on Day 7 post infection: 2.39 x 10(7) +/- 0.32 x 10(7) oocysts for controls and 7.37 +/- 10(6) +/- 3.19 x 10(6) oocysts for vaccinated birds) and after four gastric intubations of liposome entrapped antigens (oocysts output on Day 7 postinfection: 2.75 x 10(6) +/- 2.02 x 10(6) g-1 caecal material). These results represented respectively 70 and 88% protection indexes. Studies on the systemic and local antibody response after one or several infections of chickens with the parasite indicated at least 20 different molecules in the detergent antigens which are classified after immunoblotting according to their properties.     

Eimeria maxima: a comparison of two laboratory strains with a fresh isolate

Oocysts of the Weybridge and Houghton strains of Eimeria maxima and a fresh field isolate were similar and measured on average 30-9 X 22-4 mum. The Weybridge strain and the field isolate produced similar pathogenic effects in 6-week-old chickens, high doses causing 50-80% mortality and severe weight loss. The Houghton strain was slightly less pathogenic and few birds died but more oocysts were produced. With each strain, a single dose gave complete immunity to a light challenge with the homologous strain. Two or 3 immunizing doses gave complete immunity to a heavy homologous challenge but were not sufficient to protect against heterologous challenge.     

Comparative studies on the histochemical properties of M. iliotibialis lateralis from Kumamoto Cochin crossbred roaster and broiler chickens

BACKGROUND: In adults the influence of cleansing preparations on the pH, fat content and hydration of the skin is well documented. Studies in newborn and small infants have not been reported. OBJECTIVE: Our study aimed at examining whether similar effects can be ascertained in infants. METHODS: Infants without skin disease, aged 2 weeks to 16 months, entered an open, controlled and randomized study. Ten infants each had skin washed with tap water (control group), liquid detergent (pH 5.5), compact detergent (pH 5.5) or alkaline soap (pH 9.5). The pH, fat content and hydration were measured before and 10 min after cleansing. Findings were statistically evaluated by parametric covariance analysis. RESULTS: The skin pH increased from an average of 6.60 after cleansing in all groups. The smallest increase (+0.19) was observed in the control group, the largest (+0.45) after washing with alkaline soap. After treatment with liquid or compact detergent, the increase of the pH was only 0.09 higher than for the control group. In comparison to the compact and liquid detergents, the alkaline soap group had a significantly higher increase in pH. The fat content (mean starting value: 4.34 micrograms/cm2) decreased after washing in all groups; the smallest effect was observed in the control group (decrease of 0.93 micrograms/cm2), the highest for the alkaline soap group (decrease of 4.81 micrograms/cm2). In comparison to the compact and liquid detergents, the alkaline soap group had a higher decrease in fat content. This difference was significant for compact detergents. No statistically significant differences were observed for hydration before versus after washing. CONCLUSION: Each cleansing agent, even normal tap water, influences the skin surface. The increase of the skin pH irritates the physiological protective 'acid mantle', changes the composition of the cutaneous bacterial flora and the activity of enzymes in the upper epidermis, which have an acid pH optimum. The dissolution of fat from the skin surface may influence the hydration status leading to a dry and squamous skin.     

Tissue concentrations and pharmacokinetics of florfenicol in broiler chickens

OBJECTIVE: To compare the Bard BTA (bladder tumour antigen) test with voided urine cytology (VUC) in the diagnosis of recurrent bladder cancer (BC). METHODS: Urine specimens for the BTA test and VUC were collected on the same day as before cystoscopy from patients undergoing routine surveillance cystoscopy for recurrent BC. The pathologists performing VUC were blinded to the results of the BTA test. RESULTS: BC was identified by cystoscopy and biopsy in 39 of 164 study participants. The overall sensitivities of the BTA test and VUC were 54 and 28%, respectively (p < 0.05). The BTA test was more sensitive than VUC for all tumour stages and grades. For > or = T2 tumours and grade 3 tumours, respectively, the difference was statistically significant (p < 0.05). The specificities of the BTA test and VUC were 92 and 97%, respectively. Both a false-positive BTA test and VUC were found to predict recurrence. CONCLUSION: The BTA test is equal or superior to VUC in the detection of BC in patients undergoing routine surveillance for recurrent BC.     

The prevalence of campylobacters and arcobacters in broiler chickens

Chicken carcasses from a supermarket and from a poultry abattoir were examined using methods designed to isolate as many strains of campylobacters and related organisms as possible. Strains of arcobacter, but no campylobacters, were isolated from every carcass after enrichment. Campylobacter jejuni subsp. jejuni was isolated from all carcasses examined by direct plating and other Campylobacter-like strains were isolated from nine out of 15 abattoir carcasses by direct plating but not after enrichment. Only the Camp. jejuni subsp. jejuni strains could be identified to species level using a readily available identification scheme and/or a commercial identification kit. Examination of caecal contents from the 15 abattoir poultry yielded Camp. jejuni subsp. jejuni and Campylobacter-like strains from 15 and eight by direct plating, and from six and nine after enrichment, respectively. Four sites in the intestine of the abattoir birds (60 samples) were examined for arcobacters and only one strain was isolated. This indicates that arcobacters are probably not normal inhabitants of the poultry intestine. Poultry is a rich source of other campylobacteria besides the thermophilic Campylobacter spp.     

Relationship of dietary fat and lysine level with body composition in broiler chickens

Recent evidence indicates that neocortical electrocorticographic (ECoG) activation depends critically on cholinergic (ACh) inputs from the basal forebrain and serotonergic (5-hydroxytryptamine, 5-HT) inputs from the midbrain raphe to the neocortex. It appears that ACh and 5-HT block synchronized ECoG activity and induce cortical activation by a direct, local action in the neocortex that is not mediated by secondary systems. Concurrent blockade of cholinergic and serotonergic inputs to the cortex abolishes all ECoG activation, suggesting that: (a) together, ACh and 5-HT are essential for cortical activation to occur; and (b) other systems cannot maintain cortical activation in the absence of the cholinergic and serotonergic inputs. Nevertheless, additional neural systems (amygdala, locus coeruleus-noradrenaline (-NA), superior colliculus, orbitofrontal cortex, dopamine, histamine, glutamate) also modulate the ECoG and can produce cortical activation. In contrast to ACh and 5-HT, however, none of these systems are essential for the maintenance of cortical activation. Further, rather than producing activation via direct inputs to the neocortex, these systems appear to produce cortical activation by stimulating the cholinergic or serotonergic inputs to cortex. Thus, neocortical activation is maintained by multiple, parallel systems; cholinergic and serotonergic pathways are essential for activation and produce activation directly and locally in the neocortex, whereas additional pathways are not essential and contribute to activation indirectly by acting through these two direct activating inputs to the cortex.     

Diversity and prevalence of Arcobacter spp. in broiler chickens

Ninety-nine strains of Arcobacter spp., isolated from 10 chicken carcasses purchased from a supermarket and 15 chicken carcasses collected from a poultry abattoir, were speciated using a variety of phenotypic identification methods. All were tested using API Campy test strips and the 16-test (Preston) identification scheme developed for campylobacters. Fifty strains were selected for examination using a more comprehensive probabilistic identification scheme, and the identity of representative strains confirmed by protein profiling using SDS-PAGE. All 25 carcasses yielded Arcobacter butzleri. Three supermarket and 10 abattoir carcasses also carried A. cryaerophilus, and two abattoir carcasses carried A. skirrowii. The API Campy scheme proved unsatisfactory for identifying these strains: only 20 of 99 strains were accurately identified, all of which were A. cryaerophilus, the only Arcobacter sp. included in the database. Moreover, 76 of 99 strains were misidentified. The 16-test scheme identified all the arcobacter strains as A. cryaerophilus, since neither A. butzleri nor A. skirrowii had been described when the scheme was developed. The computer-assisted probabilistic scheme succeeded in identifying all but one strain, the identity of which was clarified by the use of SDS-PAGE. To our knowledge this is the first time that arcobacters other than A. butzleri have been reported in poultry meat or any other food of animal origin. Their high prevalence in poultry products may be of significance to public health.     

Changes in the generation cycle of duodenal crypt cells in chickens infected with Eimeria acervulina

Changes in the duration of the progenitor cycle and its four phases were determined for duodenal crypt cells in chickens infected with Eimeria acervulina. Metaphase curves were constructed using percent labelled metaphase nuclei in duodenal crypt cells at short intervals after the injection of [3H]thymidine. The duration of the progenitor cycle and its four phases were calculated using the synthetic index and data obtained from the metaphase curves. The cycle time was reduced from 14 h in control birds to 10.2 h at 2 days and 10.6 h at 4 days postinfection. The change was attributable entirely to a reduction in G1 or the presynthetic phase. In addition, the population of dividing cells within each duodenal crypt was almost doubled in infected birds. These increases in cell production precedes all the histological changes observed earlier in the intestines of E. acervulina infected chickens. At least in this instance, changes in crypt morphology seems, therefore, to result from an induced change in the functional activity of the crypt.     

In situ characterization of leucocyte subpopulations after infection with Eimeria tenella in chickens

We characterized the leucocyte subpopulations after infection with Eimeria tenella in both naive and immune chickens. Immunocytochemical staining was used to characterize the cells in situ, so that the interaction between host and parasite could be studied. More leucocytes were detected in the lamina propria of immune chickens, and leucocytes infiltrated the ceca more rapidly than in naive chickens, but the infiltration was less pronounced than in naive chickens. In naive chickens, most infiltrated leucocytes were macrophages and T cells. Two days after inoculation the number of CD4+ cells had increased greatly. In immune chickens, mainly T cells (CD4+ and CD8+) infiltrated the lamina propria, and in contrast to naive chickens, the number of CD8+ cells exceeded the number of CD4+ cells. Furthermore, we characterized which cells contained a parasite and which cells were detected next to the parasites, because these cells are probably involved in the arrested development of the parasites. In naive chickens, sporozoites were significantly more often located within or next to macrophages than in immune chickens. In immune chickens, sporozoites were significantly more often located within or next to CD3+, CD8+, and TCR2+ cells. In conclusion, the marked increase of CD4+ cells after primary infection suggests that these cells are involved in the induction of the immune response, whereas the increase of CD8+ cells after challenge infection suggests that these cells act as effector cells.     

Kinetics of specific immunoglobulin A, M and G production in the duodenal and caecal mucosa of chickens infected with Eimeria acervulina or Eimeria tenella

The development and appearance of antibody was studied in the intestine and serum from histocompatible GB1 chickens orally infected with oocysts of Eimeria acervulina (restricted to the duodenum) or Eimeria tenella (restricted to the caeca). The local immune response was measured as the specific antibody levels in the supernatants of intestinal fragments (duodenum and caecum) maintained in culture for 16 h at 41 degrees C, 5% CO2, 95% air. Specific IgM was detected 1 week after E. acervulina infection, and the specific IgA and IgG contents of the duodenum and caecum were significantly elevated (P < 0.001) after 2 weeks. The intestinal specific IgG content was raised. E. tenella infection resulted in specific IgA only in the parasitized area during the second week post-infection (P < 0.05). Specific IgM and IgG were both detected in the duodenum and caecum, respectively, 1 and 2 weeks p.i. Production of parasite-specific immunoglobulins was always significantly higher in the parasitized than in the unparasitized areas (caeca for E. acervulina, duodenum for E. tenella). This ex vivo culture assay of intestinal fragments used to measure the mucosal immune response of intestinal areas showed a significant production of specific IgA and IgM. In addition, high levels of IgG were also measured. The role of this specific IgG in Eimeria infection remains to be determined.     

Heterogeneity of staphylococci and other bacteria isolated from six-week-old broiler chickens

In broiler operations, various health problems develop during the final 2 wk of the growing period, resulting in increased mortality and condemnation losses. At this stage, sickly birds were found to be systemically infected by various bacteria regardless of varied clinical signs, and the purpose of this study was to carry out thorough microbiological investigations on this problem. Thirty-one 6-wk-old broilers showing signs of illness were obtained from three farms, and bacterial isolations were carried out from the blood, liver, and hock joint. Bacteria were isolated from 87, 90, and 71% of the blood, liver, and hock joint samples, respectively. Mean bacterial counts in log10 of the blood (per milliliter) and liver (per gram) were 2.15 and 2.93, respectively. Among 132 bacterial isolates, major species were Staphylococcus (60%), Corynebacterium (18%), Escherichia coli (5%), and Stomatococcus (4%). Among 79 Staphylococcus isolates, 77 were coagulase-negative. Major species of staphylococci were S. lentus (19%), S. simulans (18%), S. cohnii (13%), S. gallinarum (10%), and S. captis (7%). In addition, six species of gram-positive and five species of gram-negative organisms were isolated. Thus, the apparent systemic infections were not caused by predominant pathogenic bacterial species, and adequately described as mixed infections. There were some significant relationships between isolated bacterial species and sampling sites, suggesting that certain organisms were abundant in the environment of a particular poultry house. These results indicate that systemic infections in market age broilers are caused by mixed bacterial species and suggest that they are caused by suppressed host antibacterial systems rather than pathogenic factors of microorganisms.     

Eimeria acervulina: influence of corticosterone-induced immunosuppression on oocyst shedding and production characteristics in broilers, and correlation with a computer simulation model

An experiment was conducted to investigate the effects of immune responsiveness on excretion of oocysts after E. acervulina infection and subsequent effects on production characteristics of broilers (Gallus domesticus). These effects were determined in broilers repeatedly infected with 2.85 x 10(3) oocysts of E. acervulina and treated with various dosages of corticosterone in the diet (0, 10, 20 and 30 p.p.m.). Corticosterone treatment did not have an effect on the peak oocyst excretion, although it was administered from 4 days before initial infection. The number of oocysts excreted shortly after the peak and the length of the excretion period were increased in corticosterone-treated groups. The absence of a difference in peak oocyst excretion was ascribed to the existence of a time-lag between first contact with the parasite and rate of development of protective immunity. In a recently developed computer simulation model this period was assumed to be 5 days. Assuming that immunosuppression, through corticosterone, is only effective when protective immunity is in operation, the results indicate a time-lag of at least a few days, which supports the inclusion of such a time-lag in the computer simulation model. General immunosuppressive effects of the corticosterone treatment, monitored by antibodies and mitogen-induced lymphocyte stimulation confirmed that immunosuppression occurred shortly after medication started. Infection did not have a significant influence on production characteristics in animals without dietary corticosterone. However, with increasing corticosterone levels the negative effects of infection on production also increased.     

Salmonella prevalence in crops of Ontario and Quebec broiler chickens at slaughter

Swabs of crop contents of 635 broiler chickens were obtained from 9 Ontario and 12 Quebec processing plants and cultured for Salmonella to determine prevalence in broiler crops. Serotypes of positive cultures were determined to evaluate the serotype profile. The overall prevalence of contamination was low (4.3%). Prevalence was higher in broilers sampled in Quebec (5.8%) than in those sampled in Ontario (2.2%). In Quebec, there were differences in prevalence among the groups of broilers sampled at the various plants. These differences were believed to be attributable to differences in Salmonella prevalence among groups of flocks delivered to the plants due to the limited exposure of the chickens to the plant. The serotype profile of Salmonella isolated from the crops of broilers in this study was similar in several respects to profiles obtained from other surveys of Canadian broiler flocks using either environmental samples or cloacal swabs. Similarities included: predominance of Salmonella hadar and Salmonella heidelberg; several other common serotypes at a low prevalence; little Salmonella enteritidis isolated in other studies, and no S. enteritidis isolated in this study. Results of this field survey of Salmonella in crops of broilers are similar to those of Canadian studies of other internal and environmental sites of broilers. The similarity indicates that monitoring of Salmonella environments of flocks of live broiler chickens should define profiles of Salmonella contamination of the carcasses and would also aid in determination of Salmonella contamination status of broiler flocks. Such information would assist efforts to reduce Salmonella contamination in broiler chickens.     

The response of broiler chickens and turkey poults to steam-pelleted diets supplemented with fat or carbohydrates

The responses of growth and feed efficiency to pelleted feed was investigated in 4- to 7-wk-old broiler chickens, and in 8- to 12- and 16- to 20-wk-old turkeys. In all cases, the growth and feed efficiency responses were linear within the ranges of dietary energy tested. When energy was added by carbohydrate supplementation, weight gain and feed efficiency responses were parallel for both mash and pellets, but due to the growth response to pellets, the elevation was higher for pellets than for mash. When energy was added by fat, the growth response to pellets also resulted in an increase in function elevation but the slope of the response was lower than in mash feeding, possibly due to a decline in pellet quality as dietary fat increased. Grinding of pellets completely abolished the growth and feed efficiency responses observed when the physical form was preserved. In chickens, comparisons of ground pellets to mash suggested some decline in nutritional quality due to the process of pelleting when either carbohydrates or fat were increased in the diets. In both chickens and turkeys, the feeding of pelleted diets resulted in an increase in abdominal fat.     

Effect of feed withdrawal on Campylobacter in the crops of market-age broiler chickens

The presence of Campylobacter and Salmonella on poultry meat products remains a significant public health concern. Previous research has indicated that feed withdrawal may significantly increase Salmonella contamination of broiler crops and that crop contents may serve as an important source of Salmonella carcass contamination at commercial processing. The present study evaluated the effect of preslaughter feed withdrawal on the incidence of Campylobacter isolation in crops of market-age commercial broiler chickens prior to capture and transport to the processing plant. The incidence of Campylobacter isolation from the crop was determined immediately before and after feed withdrawal in 40 7-wk-old broiler chickens obtained from each of nine separate broiler houses. Ceca were collected from broilers in six of the same flocks for comparison with the crop samples. Feed withdrawal caused a significant (P < 0.025) increase in Campylobacter-positive crop samples in seven of the nine houses sampled. Furthermore, the total number of Campylobacter-positive crops increased significantly (P < 0.001) from 90/360 (25%) before feed removal to 224/359 (62.4%) after the feed withdrawal period. Alternatively, feed withdrawal did not significantly alter the Campylobacter isolation frequency from ceca. Similar to our previous studies with Salmonella, the present results suggest that preharvest feed withdrawal increases the frequency of Campylobacter crop contamination and, thus, provides a source of Campylobacter contamination of carcasses at commercial processing.     

Association between in vitro heterophil function and the feathering gene in commercial broiler chickens

We recently showed that in vitro heterophil functional efficiency in commercial broiler chickens is genetically controlled and may be a sex-associated trait. To further characterize the genetic mechanism(s) of heterophil functional efficiency, we wanted to determine whether the feathering gene, present on the Z sex chromosome, contributes to heterophil functional efficiency. Heterophils from two pairs of broiler lines were evaluated; each pair contained a fast feather (FF) (lines A and X) and a slow feather (SF) line (lines B and Y). On days 1 and 4 post-hatch, heterophils isolated from two sets of pure line broilers (A and B, and X and Y) were evaluated for their ability to (1) phagocytize Salmonella enteritidis, and (2) exhibit bactericidal activity against S. enteritidis. On days 1 and 4 post-hatch, heterophils isolated from the FF lines were statistically (P < or = 0.02) more proficient at phagocytizing S. enteritidis than heterophils from SF lines. Bactericidal activity was also statistically (p < or = 0.02) greater on day 1 post-hatch in the heterophils isolated from FF lines compared to heterophils isolated from SF lines. These data indicate that the presence of the FF gene locus on the Z sex chromosome contributes to heterophil function and may contribute to the early innate immune competence of a flock.     

Yeast treatment to reduce Salmonella and Campylobacter populations associated with broiler chickens subjected to transport stress

The prevalence of Campylobacter and Salmonella on retail poultry carcasses remains a significant public health concern. The stresses associated with transporting poultry prior to slaughter have been shown to increase pathogen populations both in the intestinal tract and on the carcass exterior. The yeast, Saccharomyces boulardii, was evaluated for its ability to reduce populations of Salmonella and Campylobacter in broiler chickens subjected to transport stress. Chicks, inoculated with individual strains of Salmonella and Campylobacter were held for 6 wk and then divided into two groups with half of the chickens receiving 10% dried yeast in the feed for 60 h. The birds were then caged and transported to simulate commercial conditions. After euthanatizing the birds, the ceca were aseptically removed and analyzed for Salmonella and Campylobacter. With no yeast treatment, transport stress caused the Salmonella colonization frequency to increase more than fivefold, from 3.3 to 16.7%. Yeast treatment significantly reduced the frequency of Salmonella colonization to lower than prestress levels, as no Salmonella were recovered from the ceca of these birds (P < 0.05). Similar results were obtained from birds challenged with a mixture of Salmonella and Campylobacter strains. Before transport, 53.3% of these chickens were positive for Salmonella. Transport stress increased the colonization rate to 67.5% in control birds, whereas the colonization of yeast-treated chickens decreased to 40% (P < 0.05). Frequency of Campylobacter isolation from the ceca was not affected by treatment, but Campylobacter populations present in the ceca were significantly reduced in the mixed strain trial (P < 0.05).