Evaluation of XPC and prototypes on aflatoxin-challenged broilers.

Various products and prototypes were added to poultry diets during an aflatoxin challenge on growth and histological parameters. Male broiler chicks were randomly assigned to 8 treatment groups with 8 replicates/treatment and 3 birds/replicate. Treatments were as follows: 1) negative control containing no aflatoxin (NC); 2) positive control containing aflatoxin (PC); 3) 0.1% glucomannan mycotoxin standard industry ameliorator (STD); 4) 0.1% prototype A, a proprietary mixture of a Saccharomyces cerevisiae product and diatomaceous clay; 5) 0.2% prototype A; 6) 0.15% prototype B, a proprietary mixture of a S. cerevisiae product and diatomaceous clay (PB); 7) 0.0625% XPC (S. cerevisiae fermentation product); and 8) 0.125% XPC (XPC2). All treatments except NC contained 2,280 +/- 102 ng/g of aflatoxin and were fed for 28 d. Body weight and feed intake were measured weekly. Livers were collected on d 28, weighed, and used for histopathological evaluation. Beginning weights were similar across treatments, but BW were lower (P /= 0.05) different among the treatment groups. Liver weights relative to BW were higher (P /= 0.05) compared with NC. Overall, BW gain in treatment groups PB and XPC2 was not different from NC and that corresponded to protective effects against liver lesions. Benefits observed during an aflatoxin challenge when broilers were supplemented with XPC, a fermentation product that does not contain any adsorbents, may be attributed to something other than adsorption as a primary mechanism.

Acid-base balance of the domestic turkey during thermal panting.

The objectives of this research were to evaluate the effects of thermal panting in domestic turkeys on arterial blood values for the acid-base variables, pH(a), bicarbonate concentration ([HCO(-) (3)](a)), partial pressure of carbon dioxide (P(a)CO(2)), and hemoglobin concentration [Hb]. In addition, body temperature and partial pressure of oxygen (P(a)O(2)) were measured to determine the effectiveness of panting in their control. Nine adult (23 wk) broad-breasted white turkey toms, all from the same hatch and reared contemporaneously in the same facility, were acclimated to room conditions of 19 degrees C and 65% RH. After a 1-wk control period, a 3-wk heat-stress period (32 degrees C, 65% RH) was induced, for a heat-stress group of 9 turkeys. Thermal panting began at this time and continued to its end. A 1-wk recovery period followed (19 degrees C, 65% RH) during which panting ceased. An age-matched group of 8 turkeys was similarly acclimated (19 degrees C, 65% RH) but was continued at this level to the end of the experiment. During the heat-stress period, the bicarbonate concentration increased, whereas pH(a) and P(a)CO(2) did not change significantly. Body temperature changes were not significant. Parabronchial ventilation was not compromised by panting, as noted by a significant increase in P(a)O(2). Hemoglobin concentration decreases were significant. The only significant change that occurred for the age-matched group was an increase in [Hb]. Domestic turkeys, reared in confinement, have the ability to resist changes in blood pH and prevent the development of respiratory alkalosis while panting in response to thermal stress. Normal body temperature and oxygenation of the blood are also maintained.

Salmonella prevalence in market-age turkeys on-farm and at slaughter.

The objective of this study was to compare the prevalence of Salmonella in market-age turkeys on-farm and at slaughter (i.e., before and after feed withdrawal, catching, loading, transportation, and preslaughter holding). Thirty birds were randomly selected from each of 6 commercial turkey flocks scheduled to be loaded and shipped to the abattoir during the evening of the same day. Selected birds were euthanized on the farm, and the cloacal contents, large intestine, crop, ceca, liver and gallbladder, and spleen were aseptically collected. At the abattoir, 30 birds from the same flock were randomly selected from the slaughter line, and the crop, ceca, liver and gallbladder, and spleen were collected for subsequent culture at the laboratory. All flocks studied were positive for Salmonella at slaughter. No statistical difference was found between the overall prevalence on-farm and at slaughter. At both sampling points, the overall prevalence found was 33.3%. Diverging prevalence estimates were obtained based on the different sample types collected on-farm and at slaughter. In both cases, cecal content samples had the highest relative sensitivity (73.3% on-farm and 68.3% at slaughter). This study demonstrates that the preslaughter practices of feed withdrawal, catching, loading, transportation, and holding do not significantly alter the prevalence of Salmonella in market-age turkeys. Therefore, our results suggest that it may be possible to monitor the Salmonella status of turkey production farms based on samples collected at the abattoir.

Effects of storage time and temperature after blood sampling from turkeys on plasma concentrations of potassium, sodium, and chloride.

The objectives of this research were to study the effect of several time intervals of turkey blood storage from sampling to centrifugation on plasma K, Na, and Cl concentrations and to study the effect of ambient temperature of turkey blood storage on these same variables. In the first study, 6 consecutive blood samples were obtained from each turkey. The first sample was centrifuged immediately (control), and each of the others was respectively stored for 20, 40, 60, 120, or 360 min at 22 degrees C before centrifugation and plasma harvest. In the second study, 4 consecutive blood samples were obtained from each turkey. The first sample was centrifuged immediately (control), and each of the others was respectively stored at ambient temperatures of 9, 22, and 30 degrees C for 120 min before centrifugation and plasma harvest. Plasma K concentration declines and is significant (P < 0.01) for each of the 20, 40, 60, 120, and 360 min values. Plasma Na concentration increases and Cl decreases were not significant (P < 0.01) until 360 and 120 min, respectively. Significant (P < 0.01) reductions occurred for plasma K concentration for each of the ambient temperature values but were the least at 9 degrees C and greatest when stored at 30 degrees C. Plasma Na concentration decreased (P < 0.01) when stored at 9 degrees C. Though increased (P < 0.01) when stored at 22 and 30 degrees C, the difference was not significant (P < 0.01) between samples stored at either 22 or 30 degrees C. Plasma Cl concentration was decreased (P < 0.01) from control values, but there was no significant difference (P < 0.01) among samples stored at 9, 22, and 30 degrees C. Clot formation and its retraction from serum are unduly delayed after blood is withdrawn from turkeys because birds lack the intrinsic mechanism for blood coagulation. Accordingly, serum is not appropriate for the determination of K concentration in turkeys, and plasma harvested immediately after blood sampling is the fluid of choice for K analysis.

Preharvest feed withdrawal affects liver lipid and liver color in broiler chickens.

An Iowa grain processor attempted to alter the typical 12-h preharvest fasting period by giving broilers cornstarch derivative pellets and water for 6 h followed by 6 h of no feed or water. After slaughter, plant food inspectors determined that livers from the treatment group were lighter in color than normal, and consequently a significant number of chicken carcasses were condemned for human consumption. The study reported herein was conducted to determine the effects of fasting or 3 feeding programs applied before processing on liver color, liver lipids, and liver glycogen of broilers. Dietary treatment groups consisted of 1) full-fed control broilers, 2) fasted broilers, 3) maltodextrin-fed broilers, and 4) and chickens given maltodextrin and methionine. Full-fed chickens had lighter liver coloration than chickens without access to feed for 6 or 12 h immediately prior to slaughter (P < 0.05). Lightness values for livers from full-fed control chickens (L* = 54.41) were 38% higher than those for livers from fasted broilers (L* = 39.30). Lighter liver colors in full-fed broilers were associated with higher hepatic lipid concentrations (6.38%) and more total liver lipid (4.96 g/liver) than was found in broilers without feed for 12 h. In contrast, darker livers from fasted broilers had lower levels of lipid (4.42%) and less total lipid (2.68 g/liver) than the full-fed broilers. Feeding maltodextrin pellets resulted in liver colors that were lighter (P < 0.05) than those found in fasted chickens but darker (P < 0.05) than livers from full-fed broilers. If carbohydrate supplements are fed prior to slaughter, producers should notify processing plant officials so that inspectors do not interpret light livers as an abnormal physiological state.

Effect of irradiating shell eggs on quality attributes and functional properties of yolk and white.

Shell eggs were irradiated and the physico-chemical, and functional properties of egg yolk and white were determined. The color of egg yolk was not affected, but the viscosity of egg white was dramatically lowered and became watery by irradiation. The foam capacity and foam stability of egg white were significantly decreased due to protein oxidation by irradiation. However, the texture characteristics of egg white were not changed by irradiation, indicating that irradiation may not alter the thermal characteristics of egg white proteins. Sulfur volatiles were generated by irradiation but disappeared during storage under aerobic conditions. Because egg white became watery, irradiation may not be advisable for table eggs but may be useful for pasteurizing liquid egg white or liquid whole egg without significant deterioration of their quality and functionality. In particular, the dramatic decrease in the viscosity of egg white by irradiation will improve flow of liquid egg white or liquid whole egg, which could be highly useful for egg processing.

Reticuloendotheliosis in Hungarian partridge.

A large commercial flock of Hungarian partridge (Perdix perdix) experienced elevated mortality associated with a wasting disease in May 1998. Postmortem examination of females consistently revealed a distended crop and abnormal gray-white tissue infiltrating the wall of the crop and thoracic esophagus. Neoplasia in male partridge was observed in the liver. Microscopic examination of the crop and thoracic esophagus revealed transmural masses of immature lymphocytes with frequent mitotic figures. Similar cells were observed in the liver of affected males. Virus particles consistent in size and morphology with reticuloendotheliosis virions were observed in neoplastic lymphoid cells via electron microscopy. Reticuloendotheliosis virus was isolated from each of four blood samples. This disease has not previously been reported in Hungarian partridges. Hungarian partridge may represent a potential reservoir of infection for other gamebirds, including prairie chickens.

Effects of dietary potassium supplementation for growing turkeys on leg weakness, plasma potassium concentration, and selected blood variables.

The objectives of this research were to observe the effects of increased K in the diets of growing tom turkeys from 6 to 18 wk of age on body weight, feed-to-gain ratio, and leg weakness; to study the effects of time and temperature of blood storage after sampling and before centrifugation on plasma K concentration; and to evaluate plasma creatine kinase activity as an indicator of leg weakness. Male Nicholas White turkeys were fed corn-soybean meal based starter and grower diets from 1 d to 6 wk of age. At this time, each of three dietary treatments was assigned randomly to three pens of toms, 30 toms per pen. The dietary treatments consisted of 1) corn-soybean meal control (control) diets, 2) corn-soybean meal diets supplemented with 25% more K than the control diets contained (Mod K), and 3) corn-soybean meal diets supplemented with 50% more K than the control diets (High K). Potassium carbonate was used as the source of supplemental K for the Mod K and High K diets. Calculated K concentrations of the control diets fed from 6 to 9, 9 to 12, 12 to 15, and 15 to 18 wk were 0.84, 0.74, 0.57, and 0.54%, respectively. Results of laboratory analysis of the diets agreed closely with the calculated values. By 12 wk, toms fed the High K diets weighed less (P = 0.018) than toms fed the control diets, and this difference was still evident at 18 wk (P = 0.013), even though the High K groups were changed to the control diets at 12 wk. Toms fed the Mod K diets also tended to weigh less at 16 and 18 wk than those fed the control diets, however, the diet effect at the latter time was not significant (P > 0.05). There were no consistent effects of dietary K on feed efficiency. Total incidence of leg weakness at 12 wk was greater (P = 0.015) among toms fed Mod K and High K diets than for those toms fed the control diets. These results show that dietary K concentrations greater than those usually present in corn-soybean meal based diets for growing turkeys should be avoided. Increases in dietary K concentrations were associated with increases in plasma K concentration. Storage of blood after sampling and before centrifugation decreases the plasma concentration of K. The decrease is minimized when ambient temperature of storage is decreased. Accordingly, blood should be centrifuged immediately after sampling for accurate measurement of plasma K concentration. Plasma creatine kinase activity is not a good indicator of associated leg weakness unless physical activity and stress can be controlled before blood sampling.

Immunohistochemical detection of Mycoplasma gallisepticum antigens in turkey respiratory tissues.

An avidin-biotin-immunoperoxidase diagnostic test was developed to facilitate rapid identification of Mycoplasma gallisepticum in respiratory tissues of turkeys. This procedure used polyclonal primary antibodies produced in rabbits. Turkeys were inoculated into the infraorbital sinus and trachea with the R strain of M. gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, or Frey's media. The outer walls of the infraorbital sinuses, lungs, and tracheas were collected and fixed in either 10% neutral formalin or pentanedial methyl glycol at 1, 2, 3, and 4 wk postinoculation. Tissues were subdivided and remained in each fixative for 6 or 24 hr. The avidin-biotin-immunoperoxidase diagnostic test was sufficiently sensitive to detect M. gallisepticum antigen at 1, 2, 3, and 4 wk postinoculation. Staining of M. gallisepticum was significantly more intense on infraorbital sinus epithelium than on respiratory epithelium from the trachea or lung. Statistical analysis indicated that the 6-hr fixation time offered better antigen preservation than 24 hr in a fixative. There was no difference in intensity of M. gallisepticum antigen staining in tissues fixed in methyl pentanedial glycol when compared with tissues fixed in 10% neutral buffered formalin. Significant differences in staining intensity were observed between weeks. Specificity of the avidin-biotin-immunoperoxidase test was not complete. None of the tissues from the M. meleagridis and control groups showed staining. No staining was observed in the ciliated brush border of infraorbital sinus epithelial cells from turkeys infected with M. synoviae. However, weak to moderate staining was observed in several tracheas of turkeys inoculated with M. synoviae. Improved specificity of an avidin-biotin-immunoperoxidase diagnostic test to detect M. gallisepticum in respiratory tissues of turkeys probably will require the use of multiple monoclonal antibodies directed against several different epitopes specific to the cell membrane of M. gallisepticum.

Urinary tract cryptosporidiosis in commercial laying hens.

Formalin-fixed kidney tissues from adult egg-laying chickens in two houses of an egg-production complex in the upper Midwest were submitted to Iowa State University for histopathologic examination. An increased incidence of visceral gout, average daily mortality 1%-2% higher than expected, and egg production within normal limits were observed in both houses. Numerous developing stages of Cryptosporidium were observed on the apical surface of epithelial cells lining renal collecting tubules and ureters. Scanning and transmission electron microscopy were used to visualize colonization of cryptosporidia, disruption of microvilli, and exfoliation of parasitized epithelial cells. Lymphoplasmacytic infiltration in the wall of ureters and hyperplasia of parasitized epithelial cells resulted in partial obstruction of ureters, which may have induced visceral gout in affected hens. This is the first report of urinary tract cryptosporidiosis occurring in adult hens in a modern commercial egg-production facility.

Postmortem detection of acute septicemia in broilers.

Septicemia is an unwholesome condition diagnosed during postmortem inspection in poultry slaughter establishments on the basis of macroscopic lesions. Early identification of septicemia has important public health implications. In this study, Pasteurella multocida, Escherichia coli, and Staphylococcus aureus septicemia were induced in broilers in order to determine if lesions of acute septicemia can be grossly detected in the visceral organs of broiler carcasses prior to the development of changes in the skeletal muscle. Increased spleen and liver weights were observed during the acute phase of septicemia. Airsacculitis, pericarditis, and perihepatitis were observed during the acute phase of P. multocida- and E. coli-induced septicemia; and arthritis was the earliest indicator of S. aureus-induced septicemia. These macroscopic lesions were sufficient to identify unwholesome septicemic broiler carcasses prior to the development of changes in the skeletal muscle of the carcass.

Experimental infection of C3H mice with avian, porcine, or human isolates of Serpulina pilosicoli.

C3H/HeJ (lps(d)/lps(d)) and C3H/HeOuJ (lps(n)/lps(n)) mice were infected via gastric intubation with avian, porcine, or human isolates of weakly hemolytic spirochetes classified as Serpulina pilosicoli. Upon histopathological examination of cecal tissue from mice infected with avian or porcine isolates, colonization of spirochetes attached end-on to the apical surface of enterocytes was observed. There were no apparent differences in severity of cecal lesions between the lipopolysaccharide (LPS)-responsive (C3H/HeOuJ) and LPS-hyporesponsive (C3H/HeJ) mouse strains infected with these isolates. Transmission electron microscopy showed spirochetes invaginated into the host cell membrane with resultant effacement of microvilli and loss of the glycocalyx. End-on attachment of the human isolate S. jonesii was not observed in the present studies, although weakly hemolytic spirochetes were reisolated from mice infected with S. jonesii. Moreover, results of Western immunoblot experiments showed mice developed serum antibody responses to the S. pilosicoli isolates examined. Thus, the present results indicate that specific isolates of S. pilosicoli can colonize mice and exhibit end-on attachment to cecal enterocytes.

Efficacy of aluminum hydroxide-adjuvanted Escherichia coli bacterin in turkey poults.

Aluminium hydroxide-adjuvanted Escherichia coli bacterins were evaluated for efficacy in protecting turkeys against homologous challenge. In each of six trials involving four different E. coli serotypes, poults in one group received a single subcutaneous injection at 1 day of age, poults in a second group were vaccinated twice at 1 and 14 days of age, and those in a third nonvaccinated group served as controls. Vaccinated and control turkeys were challenged at 4 wk of age and survivors were necropsied 1 wk later. Mortality and gross lesion scores of both vaccinated groups were compared with those of the nonvaccinated group. Poults vaccinated twice had significantly lower mortality and less severe gross lesions than poults receiving no vaccine prior to challenge. Immunization with one or two injections of aluminum hydroxide-adjuvanted E. coli bacterin did not impair weight gain of poults.

Adverse effects of Escherichia coli infection of turkeys were not alleviated by supplemental dietary vitamin E.

Two experiments were conducted to determine the influence of dietary vitamin E on the response of young male turkeys to Escherichia coli infection. A complete factorial arrangement of two concentrations of supplemental dietary vitamin E (12 or 300 IU/kg as dl-alpha-tocopheryl acetate) and infection or no infection of turkeys with E. coli was used in both experiments. In Experiment 1, each dietary treatment was fed to four pens of turkeys from 1 to 28 d of age. At 28 d, turkeys in two pens per dietary treatment received an injection of 3.0 x 10(7) E. coli cells into the left and right thoracic air sacs. All turkeys were necropsied 7 d after E. coli injection and the incidence and severity of lesions in air sacs, lungs, pericardium, and liver were determined. The same dietary vitamin E treatments were used in Experiment 2. Each diet was fed to eight pens of turkeys from 1 to 47 d of age. At 47 d, turkeys in four pens per dietary treatment received an injection of 3.0 x 10(7) cells of the same E. coli used in Experiment 1 into the left and right thoracic air sacs. All turkeys were necropsied as in Experiment 1 at 54 d of age. Weight gain and efficiency of feed utilization were impaired markedly by E. coli infection during the 7 d after injection. Livability also was decreased by E. coli infection in Experiment 1 but not in Experiment 2. Adverse effects of E. coli on performance and livability were not affected by dietary vitamin E concentration. Lesions observed in turkeys that received E. coli injection ranged from mild to severe, with the most severe lesions observed in air sacs. Lung lesions were observed frequently but were less severe than in air sacs. Dietary concentration of vitamin E had no effect on incidence or severity of lesions in air sacs or lungs. Overall, the results of these experiments show that adding 300 IU of vitamin E/kg of diet did not alleviate the adverse effects of E. coli infection in young turkeys.

Effect of environmental variables in turkey confinement houses on airborne Aspergillus and mycoflora composition.

Environmental conditions and airborne mycoflora were measured concurrently in 10 turkey confinement houses during warm and cold weather. The following variables in the environment were measured: numbers of feed- and litter-associated yeast and mold fungi, temperature, relative humidity, airspeed, carbon dioxide and ammonia concentration, airborne bacteria, and airborne particulate mass, particle number, and particle size distribution. Winter air in turkey confinement houses contained significantly higher concentrations of Aspergillus, Scopulariopsis, and Mucor sp. and significantly lower concentrations of Cladosporium, Fusarium, and Alternaria sp. when compared with summer air. Significantly greater numbers of Mucor sp. were recovered per cubic meter of air where the current turkey flock was present less than 100 d when compared to houses where the current flock resided 100 d or more. Management decisions regarding control of the internal environment of turkey confinement houses apparently influence airborne mycoflora composition.

Outbreak of Mycoplasma iowae infection in commercial turkey poults.

In September 1989, 17-day-old turkey poults were submitted to Iowa State University because of leg weakness and dehydration. These birds were commercial large white toms from a flock of 23,214. Lesions observed at necropsy included chondrodystrophy of the hock joints, clear fluid in hock joint spaces, valgus deformities and shortening of the tarsometatarsal bones, and curled toes. Mycoplasma iowae was isolated and identified from swabs of the air sac, cloaca, hock joint, and large intestine. Approximately 1.4% of the flock was culled between 2 and 8 weeks of age because of leg problems. M. iowae infection did not severely affect overall flock performance. Eighty-seven percent of the flock was marketed at 18 weeks of age with an average per turkey weight of 29.5 pounds.

Cecal spirochetosis in commercial laying hens.

Cecal spirochetosis in chickens has been associated with enteric disease and reduced egg production in the United States and Europe. This report describes spirochete overgrowth of cecal mucosa in chickens from a flock of 100,000 commercial layers experiencing diarrhea and a 5% drop in egg production. Spirochetes were demonstrated in the ceca by darkfield and light microscopy. Apical surfaces of cecal enterocytes were covered by a dense layer of spirochetes aligned parallel to each other and perpendicular to the mucosal surface. Weakly beta-hemolytic, indole-negative spirochetes were isolated from the ceca on BJ media under anaerobic conditions at 42 C. Chicken cecal spirochetosis may represent an economically significant enteric disease of laying hens which has heretofore been infrequently recognized.

Aspergillus fumigatus keratitis with intraocular invasion in 15-day-old chicks.

Eye infections were initially observed in single-comb white leghorn breeder chicks at 5 days of age, and morbidity increased from 0.05% to 1.5% after debeaking at 7 days of age. All chicks necropsied at 15 days of age had cheesy yellow exudate within the conjunctival sac of one eye and small (1 mm diameter) white nodular lesions in lungs and on thoracic air-sac membranes. Histopathologic examination of the eyes revealed septate fungal hyphae and inflammatory cells in the anterior chamber, cornea, and conjunctival sac. Similar fungal hyphae were present within lung granulomas. Aspergillus fumigatus was isolated from the eyes. Eye infections were the only health problem reported for several consecutive flocks on this farm. Elimination of moldy feed from the diet and environment and proper management of sawdust litter have prevented fungal ophthalmitis in subsequent flocks.