The cellular response of the fowl small intestine to primary and secondary infections of the cestode Raillietina cesticillus (Molin)

The effects of various experimental variables upon the optimum temperatures for positive inotropic and chronotropic responses to isoprenaline in isolated cardiac preparations were examined. Perfusion rate and animal (heart) size affected the satisfactory determination of rate and tension optima of guinea-pig and rabbit perfused hearts. Isolated spontaneous atria were assumed to have the same temperature optima as perfused hearts and these were independent of the animal size/age. Paced atria, in which spontaneous rate changes were absent, revealed a sharper tension optimum at an unaltered temperature. The inotropic optimum in all preparations varied with the method of expressing the response; however, since the increase tension remained independent of resting developed tension in pacing experiments, this measure was adopted. The resulting inotropic and chronotropic optima, having minimized these variables, were 25 and 35, and 30 and 37.5 degrees C for guinea-pigs and rabbits respectively. This confirms the separation of these responses by temperature.     

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.     

Pathogenicity of Mycoplasma synoviae in broiler chickens

Six isolates of Mycoplasma synoviae, identified as WVU 1853, K1968, K1858, 92D8034, F10-2AS, and FMT, were compared for pathogenicity in broiler chickens. Specific-pathogen-free chickens were inoculated, in two groups of 20, with each isolate by footpad or eyedrop inoculation at 1 day of age and were examined at necropsy 7, 14, 28, and 42 days postinoculation. Specimens were taken for histopathology, culture, polymerase chain reaction assay, and hemagglutination-inhibition serology. Isolates were grouped according to pathogenicity on the basis of differences in lesion development and tissue distribution in the respiratory system, other viscera, and the skeletal system. K1968 (pathogenic) induced lesions in all sites examined in both the footpad and eyedrop inoculation groups. It was detected in all sites following footpad inoculation and in all sites except viscera following eyedrop inoculation. WVU 1853, K1858, and 92D8034 (moderately pathogenic) induced lesions and were detected in all sites following footpad inoculation. With eyedrop inoculation, lesions were identified only in upper and lower respiratory sites, and organisms were detected only in upper respiratory sites. F10-2AS (moderately pathogenic) was similar; however, footpad inoculation failed to induce visceral lesions or permit organism detection in any site. F10-2AS was detected in upper and lower respiratory tissues following eyedrop inoculation. FMT (mildly pathogenic) induced only upper respiratory lesions when either footpad or eyedrop inoculation was used, and detection was restricted to upper respiratory sites following eyedrop inoculation. These results are useful in comparative evaluations of the virulence of other M. synoviae isolates and form a basis for characterization of virulence factors of M. synoviae.     

Utilization of spent hen meal in diets for broiler chickens

Studies were conducted to evaluate spent hen meal (SHM) produced in commercial rendering plants as a nutrient source in diets for broiler chickens. Utilizing previously determined nutrient composition values, including digestible amino acid and TMEn content, diets were formulated to include 0, 5, 10, and 15% of SHM from three different locations. In the first experiment, conducted in battery pens from 1 to 21 d posthatch, diets were formulated with digestible amino acid requirements set at 90, 95, or 100% of NRC (1994) total amino acid requirements. In the second experiment, conducted in floor pens from 1 to 49 d posthatch, diets were formulated with digestible amino acid requirements set at 95% of NRC (1994) total amino acid requirements. Samples of birds from the second experiment were processed to determine the possible influence of SHM inclusion on carcass yield. Results of the present studies indicate that SHM from commercial rendering facilities can be utilized in diets for growing broiler chickens provided adjustments are made in nutrient content and digestibility. When formulated on the basis of digestible amino acid content, levels of SHM up to 10% appear acceptable based upon body weight, feed conversion, bone ash, and carcass yield. Higher inclusion rates generally reduced performance. It is apparent that differences in nutritional quality may exist among products produced by different rendering facilities; however, evaluation of products to assess nutrient quality may be difficult under commercial conditions. As more information is generated regarding typical amino acid content and digestibility of rendered SHM, the product may be used with greater confidence in commercial diets.     

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.     

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.     

Physiological effects of gentian violet on broiler chickens

The effects of dietary gentian violet upon certain physiological parameters of broiler chickens were studied. Gentian violet exhibited no effect upon growth rates or feed conversion ratios at dietary levels of 16, 32, or 64 micrograms/g. In vitro intestinal absorption of methionine and glucose was also unaltered. Dietary gentian violet significantly increased hemoglobin concentration without an effect on packed cell volume. Furthermore, commercial gentian violet containing preparations, when incorporated into the diet, resulted in increased intestinal absorption of Fe59 but this increase was dependent upon type of inert carrier used. Dietary gentian violet alleviated some of the growth suppression caused by dietary aflatoxin; however, no effect was observed on plasma pigmentation. These data suggest that dietary gentian violet possesses effects other than those for which it has been traditionally employed.     

Incidence of Campylobacter in crops of preharvest market-age broiler chickens

Previous research has identified cecal and intestinal contents as sources for Campylobacter contamination of broiler carcasses in the processing plant. During the present study, we evaluated the crop contents of preharvest market-age broilers as a potential reservoir of field-derived Campylobacter in the processing plant. Crops were collected aseptically from 40 randomly selected market-age broilers in each of nine commercial broiler flocks. Ceca were collected from broilers in six of the same flocks for comparison with the crop samples. The presence of Campylobacter in the crops and ceca was determined by enrichment culture in Bolton broth followed by culture on Campy-Ceflex plates. Campylobacter was isolated from the crop contents of broilers in seven of the nine flocks and from the cecal contents in three of six flocks. The incidence of Campylobacter-positive crop samples among all birds evaluated (224/359; 62%) was significantly higher (P < 0.001) than the number of positive cecal samples (9/240; 4%). The results indicate that the incidence of Campylobacter contamination of crop contents may exceed that of the cecal contents by as much as 37-fold in some broiler flocks, and may represent a critical preprocessing control point in reducing Campylobacter entry into the processing plant.     

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.     

Impedance recordings to determine change in extracellular volume in the brain following cardiac arrest in broiler chickens

The present study describes a method to determine the onset and development of brain damage in broiler chickens. Exsanguination disrupts the brain metabolism and causes the brain to become ischemic. Energy-requiring systems in the cell membrane fail, which results in an ionic shift over the membrane, accompanied by a water influx into the cell. This cellular edema decreases the extracellular volume of brain tissue. In mammals, this brain damage has been measured by recording brain impedance. We adapted this approach for use with poultry. Five to six-week-old commercial broilers were equipped with impedance recording electrodes in the striatum area of the brain. Cardiac arrest was induced by means of an intravenous injection of MgCl2 and brain impedance was recorded for 30 min. The resulting curves showed a high similarity to those obtained in rats. No effects of 12 h antemortem feed deprivation on the size and rate of change in brain impedance could be found. Both in anesthetized and conscious birds, a change in brain impedance was found. We conclude that brain impedance can be used to determine the development of ischemic brain damage in broiler chickens.     

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.     

Occurrence of Erysipelothrix spp. in broiler chickens at an abattoir

From September 1995 to August 1996, 750 chickens from 66 farms sent to an abattoir in Nagano Prefecture, Japan, were examined for the presence of Erysipelothrix spp. Erysipelothrix spp. were isolated from 118 (15.7%) of 750 skin samples, 27 (7.3%) of 372 hypoderm samples, 12 (1.9%) of 630 throat samples, 106 (59.2%) of 179 feather samples, and none of 257 spleen samples. Of 66 farms, 55 farms (83.3%) sent Erysipelothrix-positive chickens and 11 farms (16.7%) only negative ones. Of 297 Erysipelothrix isolates, 273 isolates were identified as Erysipelothrix rhusiopathiae and 24 as Erysipelothrix tonsillarum. E. rhusiopathiae isolates were serotyped into nine different serovars. Of the 273 E. rhusiopathiae isolates, 33 (11.1%) were serotyped to serovar 6; 22 (7.4%) were serovar 5; 19 (6.4%) were serovar 2; 15 (5.1%) were serovar 8; 2 (0.7%) were serovar 21; 4 each (1.3% each) were serovars 1b, 9, 12, and 19; and 178 (59.9%) were untypeable. Of 24 E. tonsillarum isolates, 15 (5.1%) were serotyped to serovar 3, and 9 (3.0%) were serovar 7. These findings indicate that chickens seem to be a potential reservoir of Erysipelothrix spp. in nature and to be a source of human Erysipelothrix infection.     

Changes in the somatosensory evoked potentials and spontaneous electroencephalogram of broiler chickens during exposure to gas mixtures

1. Six week-old broiler chickens implanted with electroencephalogram (EEG) recording and somatosensory stimulating electrodes were exposed to either 90% argon in air, a mixture of 30% carbon dioxide and 60% argon in air or a mixture of 30% oxygen and 40% carbon dioxide (balance nitrogen) for 2 min, to determine the times to onset of changes in spontaneous EEG and the loss of somatosensory evoked potentials (SEPs) and thus unequivocal loss of consciousness. 2. In addition, after a 2 min exposure to the carbon dioxide-oxygen mixture, some broilers were allowed to recover in air and their EEGs and SEPs were continuously recorded until the return of normal EEG and SEPs. During this period, the time to return of response to comb pinching was also determined in 10 broilers. 3. All broilers exposed to either argon or the carbon dioxide-argon mixture died within 2 min, whereas, only 3 out of 17 broilers died during the 2 min exposure to the carbon dioxide-oxygen mixture. 4. During exposure to argon, unlike the other 2 gas mixtures, the majority of broilers showed high amplitude, low frequency electrical activity in the EEG on average at 10 s. The mean times to onset of EEG suppression were 17, 19 and 40 s after exposure to argon, the carbon dioxide-argon mixture and the carbon dioxide-oxygen mixture, respectively. An isoelectric EEG occurred on average at 58 and 41 s after exposure to argon and the carbon dioxide-argon mixture, respectively. An isoelectric EEG did not occur in broilers which were exposed to the carbon dioxide-oxygen mixture. 5. The SEPs were abolished in broilers on average 32 and 24 s after exposure to argon and the carbon dioxide-argon mixture, respectively. During exposure of broilers to the carbon dioxide-oxygen mixture the SEPs were abolished in the majority of birds on average at 47 s, however, 2 out of 14 birds retained their SEPs for the entire period of 2 min exposure to this gas mixture. 6. During the recovery after exposure to the carbon dioxide oxygen mixture, response to comb pinching and SEPs returned either at the time of, or soon after, the onset of high frequency electrical activity in the suppressed EEG of broilers. The mean times to return of response to comb pinching and SEPs were 52 and 43 s, respectively. 7. Based on the time to onset of EEG suppression or loss of SEPs, exposure of broilers to either 90% argon in air, or a mixture of 30% carbon dioxide and 60% argon in air, resulted in quicker loss of consciousness than during exposure to a mixture of 40% carbon dioxide, 30% oxygen and 30% nitrogen. The time to return of consciousness after a 2 min exposure to the carbon dioxide-oxygen mixture was also found to be rapid.     

Nutritional aspects of hydrogenated and regular soybean oil added to diets of broiler chickens

The objective of the present study was to evaluate the effect of degree of saturation of fat incorporated into broiler diets on performance and body fatty acid (FA) profile. The various degrees of saturation were achieved by using regular soybean oil (SO) and hydrogenated soybean oil (HSO), mixed at different proportions. The work was carried out on commercial broilers (Experiment 1) and on lines of chickens divergently selected for high (HF) or low (LF) abdominal fat (Experiment 2). Daily BW gain and gain:feed ratio increased and the amount of feed intake decreased as the dietary fat saturation decreased. Digestibility of total fat and of each of the FA was lowest in the HSO group and reached maximal values when 23% or more of the added oil was SO. The AMEn values of the diets were almost parallel to fat digestibility. The performance of the HF and LF chickens was affected by the degree of saturation similarly to that observed for the commercial stock. The degree of dietary fat saturation had very little effect on saturated FA (C16:0 and C18:0) in body lipids, reduced the level of monoenoic FA (C16:1 and C18:1), and raised that of polyunsaturated FA (PUFA) (C18:2, C18:3, and C20:4). Monoenoic FA were higher, whereas PUFA were lower in the HF than in the LF line. The improved AMEn in diets containing unsaturated fat is probably due to higher fat digestibility, direct deposition of PUFA in body lipids, and lower lipogenesis, associated with lower heat production.     

Efficacy of various inorganic sorbents to reduce the toxicity of aflatoxin and T-2 toxin in broiler chickens

Experiments were conducted to determine the efficacy of three inorganic sorbents, S1, S2, and S3, to reduce the toxicity of aflatoxins (AF) and T-2 toxin in male broiler chickens from day of hatch to 21 d of age. The compounds had been reported to bind to AF and T-2 toxin in vitro. S1 and S2 were the same basic compound that had been stored for different lengths of time following activation. In Experiments 1, 2, and 3, the appropriate diets were produced to contain no mycotoxins, the specific adsorbent at 0.5% of diet, AF alone at 5 mg/kg of diet, T-2 alone at 8 mg/kg of diet, AF at 5 mg/kg of diet plus the specific sorbent at 0.5% of diet, or T-2 at 8 mg/kg of diet plus the specific sorbent at 0.5% of diet. The specific sorbents used were: 1) Experiment 1, S1; 2) Experiment 2, S1 and S2; and 3) Experiment 3, S3. In Experiments 1 and 3, S1 and S3, respectively, showed no protection against AF or T-2 toxin as measured by BW gain, when compared to AF alone group. In Experiment 2, S1 showed no protection; however S2 reduced the effects of AF on BW gain by 25% as compared to AF alone diet. The data demonstrate that under the conditions of our experiment: 1) one of the sorbents provided some protection against aflatoxicosis; 2) there was variability in protection against aflatoxicosis between two different samples of the same sorbent that had been stored for different lengths of time following activation; 3) protection by the sorbents against the effects of T-2 toxin was not observed.     

Effect of temperature of wet extrusion on the nutritional value of full-fat soyabeans for broiler chickens

1. An experiment was conducted to determine the temperature for wet extrusion of full-fat soyabeans (FFS) needed to produce maximum chicken performance. 2. FFS were either unprocessed or extruded at 5 different temperatures (118 degrees, 120 degrees, 122 degrees, 126 degrees and 140 degrees C) in a wet extruder. Diets were prepared with the different FFS, and a diet prepared with soyabean meal (SBM) was included as a control. The 7 experimental diets were fed to individual groups of 40 chickens each, for a period of 35 d. Trypsin inhibitor activity (TIA), urease activity (UA), and protein solubility in potassium hydroxide (PS) were measured in all FFS and in the SBM. 3. Diets prepared with raw FFS and FFS extruded at 118 degrees and 120 degrees C resulted in significantly lower body weights and in pancreatic hypertrophy; maximum growth rate was obtained with FFS extruded at 122 degrees and 126 degrees C, while minimum pancreas weight was seen in chickens fed FFS extruded at 140 degrees C. 4. Although TIA, UA, and PS all decreased with increasing temperature of extrusion, TIA provided the best prediction of the feeding value of soyabeans for chickens.     

Use of fenbendazole for long-term control of protostrongylid lungworms in free-ranging Rocky Mountain bighorn sheep

In an effort to control Protostrongylus spp. in a Rocky Mountain bighorn sheep herd (Ovis canadensis canadensis) of approximately 30 animals, fenbendazole-medicated salt was placed on the Stillwater bighorn winter range in southcentral Montana (USA) for four consecutive winters, 1990 to 1993. Sheep of all age and sex classes were observed using the medicated salt throughout the study period. Prevalence and average number of lungworm larvae per gram of bighorn feces declined significantly (P < 0.05) from pretreatment levels (1987 to 1989), and remained low throughout the study period. Free-choice availability of fenbendazole-medicated salt is a potentially effective management tool for long-term control of protostrongylid lungworm.     

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.     

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.