Experimental infections in domestic ducks with Cryptosporidium baileyi isolated from chickens

Oral inoculation of 13 ducks (Anas platyrhynchos) with 1 x 10(6) Cryptosporidium baileyi oocysts produced patent infections but no clinical signs of disease. Intratracheal inoculation of 13 ducks with 1 x 10(6) C. baileyi oocysts produced only mild clinical signs of respiratory disease, no deaths, and gross lesions of airsacculitis in only three ducks. The distribution of developmental stages of C. baileyi in ducks was similar to that observed in experimentally infected chickens and turkeys. Results of this study indicate that ducks are more resistant to experimentally induced respiratory cryptosporidiosis caused by C. baileyi than are chickens and turkeys.     

Chemoprophylaxis of cryptosporidiosis in chickens, using halofuginone, salinomycin, lasalocid, or monensin

Chemoprophylaxis of Cryptosporidium baileyi infections was attempted by feeding 4 groups of chicks diets containing 3 mg of halofuginone/kg of feed, 60 mg of salinomycin/kg, 75 mg of lasalocid/kg, or 110 mg of monensin/kg. Rations were fed 5 days before oral or intratracheal inoculation with oocysts and were continued for 20 days. None of the drugs prevented C baileyi infections. Clinical signs of respiratory tract disease and gross lesions of airsacculitis were observed in intratracheally inoculated birds in all treatment groups and nonmedicated controls. Orally inoculated birds did not develop clinical signs of infection. Pathogenic bacteria were not isolated from the respiratory tract systems of any chicks. Halofuginone delayed the establishment of infections of the bursa of Fabricius and cloaca, but not of the trachea.     

Chronic effects of moniliformin in broiler and turkeys fed dietary treatments to market age

Floor pen studies were conducted, with broilers from 1 to 7 wk of age and with turkeys from 1 to 14 wk of age, to evaluate the chronic effects of moniliformin (M). Fusarium fujikuroi (M-1214) culture material was added to typical corn-soybean basal diets to supply 0, 25, or 50 mg M/kg diet (broilers) or 0, 12.5, 25, 37.5, or 50 mg M/kg diet (turkeys). Compared with controls, chicks fed diets containing 50 mg M/kg consumed more feed, had lower body weight gain, were less efficient in converting feed to body weight gain, and had increased relative heart and proventriculus weights. Chicks fed the diet containing 50 mg M/kg also had significantly higher mortality and decreased mean corpuscular volumes compared with controls. Broilers fed 25 and 50 mg M/kg also had increased serum gamma glutamyltransferase activities. Feed intake, body weight gain, and feed conversion of turkeys fed dietary M were not affected. At 6 and 14 wk, turkeys fed 25, 37.5, or 50 mg M/kg diet had increased (P < 0.05) relative heart weights when compared with controls. At week 14, turkeys fed diets containing 37.5 or 50 mg M/kg also had increased (P < 0.05) relative liver weights compared with turkeys fed 0, 12.5, or 25 mg M/kg diet. Lesions, observed only in the hearts of broilers and turkeys fed 50 mg M/kg, were loss of cardiomyocyte cross striations, increased cardiomyocyte nuclear size, and an increased number of cardiomyocyte mitotic figures (turkeys only). Results indicate that > or = 37.5 mg M/kg is hepatoxic and > or = 25 mg M/kg is cardiotoxic to turkeys and 50 mg M/kg diet is toxic to broilers fed to market age.     

隐孢子虫卵囊形态学观察及动物交叉感染试验

作者观察了从湖南６种动物分离出的隐孢子虫卵囊的光镜下形态，并以鸡源、牛源和猪源隐孢子虫卵囊人工感染实验动物作交叉感染性研究。结果鉴定出隐孢子虫３个种，即贝氏隐孢子虫（Ｃ．ｂａｉｌｅｙｉ），寄生于鸡、鸭；微小隐孢子虫（Ｃ．Ｐａｒｖｕｍ），寄生于牛、山羊、猪、家兔和小鼠；鼠隐孢子虫（Ｃ．ｍｕｒｉｓ），寄生于牛。交叉感染结果表明，来自鸡的隐孢子虫可以感染雏鸡和雏鸭，而不能感染小鼠和家兔；来自牛的隐孢子虫可以感染小鼠和家兔而不能感染雏鸡，来自猪的隐孢子虫可以感染小鼠而对雏鸡无感染性。作者认为，哺乳类和鸟类的隐孢子虫可能在宿主纲的水平上具有宿主持异性。     

Effect of Cryptosporidium baileyi on broilers infected at 26 days of age

Cryptosporidium baileyi causes respiratory disease, pallor, death, and transient increased feed conversion (FC) and decreased body weight gain (BWG) when intratracheally (IT) inoculated into young chicks. Unlike the case for young chicks in previous studies, C. baileyi had no effect on FC, BWG, or mortality in IT-inoculated 26-day-old chicks. Results from two different histologic evaluations indicated that IT inoculation with 10(4) oocysts caused higher epithelium lesion scores (P less than 0.05) and higher mucosal area scores (P less than 0.05) than did IT inoculation with more, fewer, or no oocysts. Reasons for these findings and implications of chicken immune system response to or modulation by C. baileyi are discussed.     

Performance and oocyst shedding in broiler chickens orally infected with Cryptosporidium baileyi and Cryptosporidium meleagridis

To study effects of experimental cryptosporidiosis, broiler chickens were infected per os with 5 x 10(5) oocysts of Cryptosporidium baileyi and Cryptosporidium meleagridis. In the first experiment, chickens were infected with oocysts of C. baileyi at the age of 7, 14, and 21 days. In the second experiment, chickens were infected with oocysts of C. baileyi, C. meleagridis, or both cryptosporidial species at the age of 7 days. Although clinical signs of infection were apparent, neither final live weight nor mortality was significanty influenced in chickens infected with a single Cryptosporidium species. In chickens infected with C. meleagridis, the growth retardation was observed in the 2-wk period after infection. The compensatory growth, however, started when the oocyst shedding had ceased. The number of oocysts in excreta specimens of chickens infected with C. meleagridis was two to three times lower than in excreta of chickens infected with C. baileyi. Chickens infected with both C. baileyi and C. meleagridis (5 x 10(5) oocysts of each) had significantly lower final live weight and worse feed efficiency than chickens of other groups. Concurrent infection did not influence individual C. baileyi or C. meleagridis oocyst shedding.     

Cryptosporidium baileyi: effects of intra-abdominal and intravenous inoculation of oocysts on infectivity and site of development in broiler chickens

Developmental stages of Cryptosporidium baileyi were observed on the epithelium of the larynx, trachea, primary and secondary bronchi, air sacs, bursa of Fabricius, and cloaca of 12 chickens inoculated intra-abdominally with oocysts. All 12 birds inoculated intra-abdominally developed clinical signs of respiratory disease and had gross lesions of airsacculitis at necropsy. Developmental stages of C. baileyi and clinical signs of disease were not observed in 12 chickens inoculated intravenously with oocysts. The response of chickens to intra-abdominal inoculation of oocysts was similar to responses recorded following intratracheal inoculation of oocysts in previous studies.     

Photosensitizing effects of Cymopterus watsonii and Cymopterus longipes in chickens and turkey poults

Two-week-old straight-run white broiler chicks and 2-week-old straight-run white turkey poults were fed seed or whole plants Cymopterus watsonii or seed of Cymopterus longipes at 0.4, 0.8, and 1.6% of body weight, and then placed in sunlight for 5 hours each day for 7 days. All plant material produced moderate to severe photosensitivity in chicks. Toxic signs included photophobia; red discoloration of beak, comb, and feet; loss of feathers in the periorbital area; dried serous fluid on comb and edge of beak; keratoconjunctivitis; and multiple lesions on feet and legs. Turkey poults showed a syndrome similar to that of chicks. Mortality was particularly high in turkeys fed C. longipes seed. Toxic signs in turkeys 6 weeks after treatment included tremors in the legs; upturning and shortening of the upper beak; and shortening disfigurement, and gangrene of the toes. Two phototoxic furocoumarins, oxypeucedanin and isoimperitorin, were isolated from C. longipes seed. Either compound, administered orally, produced photosensitivity in 2-week-old chicks.     

Experimental and serologic observations on avian pneumovirus (APV/turkey/Colorado/97) infection in turkeys

An avian pneumovirus (APV) was isolated from commercial turkeys in Colorado (APV/Colorado) showing clinical signs of a respiratory disease. The results of virus neutralization and indirect fluorescent antibody tests showed that the APV/Colorado was partially related to APV subgroup A but was unrelated to APV subgroup B. Turkeys experimentally inoculated with the APV/Colorado were observed for signs, lesions, seroconversion, and virus shedding. Thirty-six 7-wk-old turkeys were distributed into three groups. Eighteen turkeys were inoculated oculonasally with APV/Colorado, six were placed in contact at 1 day postinoculation (DPI), and 12 served as noninoculated controls. Tracheal swabs and blood samples were collected at 3, 5, 7, 10, 14, and 21 DPI. Tissues were collected from three inoculated and two control turkeys on aforementioned days for pathologic examination and APV isolation. Inoculated turkeys developed respiratory disease, yielded APV at 3, 5, and 7 DPI, and seroconverted at 10 DPI. Contact turkeys yielded APV at 7 and 10 DPI. No gross lesions were observed in the turbinates, infraorbital sinuses, and trachea. However, microscopic examination revealed acute rhinitis, sinusitis, and tracheitis manifested by congestion, edema, lymphocytic and heterophilic infiltration, and loss of ciliated epithelia. The inflammatory lesions were seen at 3 DPI and became extensive at 5 and 7 DPI. Active regenerative changes in the epithelia were seen at 10 and 14 DPI. Serologic survey for the presence of antibodies in commercial turkeys (24,504 sera from 18 states) and chickens (3,517 sera from 12 states) to APV/Colorado showed seropositive turkeys in Minnesota, North Dakota, and South Dakota and no seropositive chickens. This report is the first on the isolation of an APV and APV infection in the United States.     

Experimental infection in specific-pathogen-free chicks with avian reovirus and avian nephritis virus isolated from broiler chicks showing runting syndrome

Avian reovirus (ARV) and avian nephritis virus (ANV) were individually isolated from runty 10-day-old broiler chicks. The ARV isolate, IR-R, the ANV isolate, IR-N, and the reference strain of ANV, G-4260, were inoculated orally into 1-day-old chicks of two specific-pathogen-free (SPF) chicken lines, 151 and PDL-1. Growth retardation without the presence of gross lesions was clearly observed at 7 and 14 days postinoculation (PI) in chicks of both lines inoculated with the IR-R strain. On the other hand, in chicks inoculated with IR-N strain, growth retardation was observed only in the chicks of line 151 at 7 and 14 days PI. Microscopically, nephritis was observed in both chicken lines at 7 and 14 days PI. When chicks that were inoculated with the IR-N strain at 1 day of age were inoculated with the IR-R strain at 3 days of age, growth retardation was observed in the chicks of line PDL-1 at 10 and 17 days PI. However, the growth retardation was less severe than in the group receiving a single inoculation of the IR-R strain.     

Pulse and continuous oral norfloxacin treatment of experimentally induced Escherichia coli infection in broiler chicks and turkey poults

Experimental colibacillosis was produced in 40 healthy, 7-day-old broiler chickens and turkeys by intratracheal injection of 1 x 10(8) CFU/chick and 1.23 x 10(9) CFU/poult bacteria of an O1:F11 strain of Escherichia coli, respectively. Two days before E. coli challenge all chicks were vaccinated with a live attenuated strain of infectious bronchitis virus (H-52). This model of infection--at least in chicken--proved to be useful for evaluating the efficacy of antimicrobial medication, by recording mortality, body weight gain, pathological alterations and frequency of reisolation of E. coli. Using this model, the efficacy of two different dosing methods of norfloxacin (continuous and pulse dosing) was evaluated. The once-per-day pulse dosing of norfloxacin administered via the drinking water at 15 mg/kg body weight proved to be more efficacious than the continuous dosing method of 100 mg/L for 5 days in chickens, while there were no convincing differences between the two treatment regimens in turkeys. The results confirmed earlier observations on the pharmacokinetic properties of norfloxacin in chicks and turkeys (Laczay et al., 1998).     

Interaction of reovirus and Cryptosporidium baileyi in experimentally infected chickens

No clinical signs, gross lesions, or increased mortality were observed in specific-pathogen-free chickens orally inoculated at 5 days of age with Cryptosporidium baileyi, reovirus 2035, reovirus 2408, or combinations of these agents. Weight gain of chickens inoculated with only reovirus 2408 was depressed 0-8 days postinoculation (PI) (P less than 0.01) but not for the 21-day period PI. Weight gain of chickens inoculated with only reovirus 2035 was not affected. Cryptosporidium baileyi infection significantly depressed weight gain 8-14 days PI but not for the entire 21-day period PI. Weight gain of chickens infected with both C. baileyi and reovirus 2035 was significantly depressed 0-14 days PI and for the entire 21-day period PI. Dual infection with C. baileyi and either reovirus appeared to promote shedding of both agents. Cryptosporidia were found principally in the rectum 2-10 days PI and in the bursa of Fabricius 6-10 days PI. Reovirus infection did not cause any microscopic lesions and did not modify lesions caused by C. baileyi infection.     

Pathogenicity of turkey coronavirus in turkeys and chickens

We designed this study to compare the replication potential of turkey coronavirus (TCV) and its effect in chickens and turkeys and to study the effect of singleand combined infection of turkey poults with TCV and astrovirus. We studied the pathogenicity of TCV in experimentally inoculated turkey poults and chickens by observing the dinical signs and gross lesions. Two trials were conducted with 1-day-old and 4-wk-old specific-pathogen-free turkey poults and chickens. One-day-old turkey poults developed diarrhea at 48 hr postinoculation. Poults euthanatized at 3, 5, and 7 days postinoculation had flaccid, pale, and thin-walled intestines with watery contents. The 4-wk-old turkeys had no clinical signs or gross lesions. One-day-old and 4-wk-old chicks developed no clinical signs or gross lesions although the TCV was detected in gut contents of the birds throughout the experimental period (14 days). In another experiment, mean plasma D-xylose concentrations in 3-day-old turkey poults inoculated with TCV, turkey astrovirus, or a combination of both viruses were significantly lower than in the uninoculated controls.     

Experimental avian paramyxovirus serotype-3 infection in chickens and turkeys

Avian paramyxoviruses (APMV) are divided into nine serotypes. Newcastle disease virus (APMV-1) is the most extensively characterized, while relatively little information is available for the other APMV serotypes. In the present study, we examined the pathogenicity of two divergent strains of APMV-3, Netherlands and Wisconsin, in (i) 9-day-old embryonated chicken eggs, (ii) 1-day-old specific pathogen free (SPF) chicks and turkeys, and (iii) 2-week-old SPF chickens and turkeys. The mean death time in 9-day-old embryonated chicken eggs was 112 h for APMV-3 strain Netherlands and > 168 h for strain Wisconsin. The intracerebral pathogenicity index in 1-day-old chicks for strain Netherlands was 0.39 and for strain Wisconsin was zero. Thus, both strains are lentogenic. Both the strains replicated well in brain tissue when inoculated intracerebrally in 1-day-old SPF chicks, but without causing death. Mild respiratory disease signs were observed in 1-day-old chickens and turkeys when inoculated through oculonasal route with either strain. There were no overt signs of illness in 2-weeks-old chickens and turkeys by either strain, although all the birds seroconverted after infection. The viruses were isolated predominantly from brain, lungs, spleens, trachea, pancreas and kidney. Immunohistochemistry studies also showed the presence of large amount of viral antigens in both epithelial and sub-epithelial lining of respiratory and alimentary tracts. Our result suggests systemic spread of APMV-3 even though the viral fusion glycoprotein does not contain the canonical furin proteases cleavage site. Furthermore, there was little or no disease despite systemic viral spread and abundant viral replication in all the tissues tested.     

Metabolisable energy determinations using chicks and turkeys

Experimental mashes containing different proportions of maize, wheat, barley and oats were fed to young broiler chickens and turkeys. Metabolisable energy (ME) determinations were carried out from 5 to 7 and from 19 to 21 d of age.

The turkeys obtained 3.2 and 1.7% more metabolisable energy than chicks from the diets used when assessed on a classical ME and N‐corrected ME basis respectively. The difference was smaller when maize formed a major part of the diet than for the other cereals. Higher ME values were also obtained in the older birds but the effect was not reproducible.     

Real-timeqPCR检测鸡胚中贝氏隐孢子虫方法研究

为检测鸡胚中贝氏隐孢子虫,本研究根据GenBank公布的贝氏隐孢子虫和原鸡18SrRNA基因序列设计针对贝氏隐孢子虫的特异性引物,并以贝氏隐孢子虫卵囊基因组DNA为模板,建立检测贝氏隐孢子虫SYBRGreen实时荧光定量PCR（Real—timeqPCR）方法,同时对贝氏隐孢子虫在鸡胚中培养7d后尿囊膜和尿囊液样品中虫体DNA进行检测。结果表明,建立的SYBRGreenreal—timeqPCR方法可特异性检测到贝氏隐孢子虫,建立的标准曲线线性关系良好（R2=0．998）,卵囊基因组DNA检测阈值为10个卵囊,重复检测结果显示试验重现性较好。该方法成功检测到尿囊膜和尿囊液中虫体DNA。本研究建立了快速、特异的定量检测鸡胚中贝氏隐孢子虫real—timeqPCR方法,可用于对贝氏隐孢子虫在鸡胚中繁殖规律分析和抗隐孢子虫药物筛选等研究。     

Requirements of the young turkey for sulphur amino acids and threonine: comparison with other species.

1. The requirements of the 3-week-old turkey for the sulphur containing amino acids and for threonine were estimated to be 0.83% and 0.94% respectively in diets containing 12.5 MJ ME/kg. 2. It is suggested that the growth responses of rats and slow-growing chicks and of fast-growing chicks and young turkeys to daily intakes of the sulphur containing amino acids and of threonine are similar.     

Pasteurella anatipestifer infection in commercial meat-type turkeys in California

A disease outbreak characterized by respiratory signs, occasional neurologic signs, and increased mortality in commercial meat turkeys from four separate companies in central California was investigated in the late summer and early fall of 1986. The disease syndrome affected turkeys from 6 to 15 weeks of age and caused a severe fibrinous pericarditis, perihepatitis, and airsacculitis. Bacteriologic and serologic examinations as well as virus- and chlamydia-isolation attempts initially failed to implicate an etiologic agent. Eventually culture attempts were made in a 5% CO2 incubator, resulting in isolation of Pasteurella anatipestifer. The disease syndrome was reproduced in young turkeys and broiler chicks inoculated with the organism.     

Pathogenicity of Salmonella enteritidis phage types 4, 8, and 23 in broiler chicks.

Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each. Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage. Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE. One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S. pullorum. A group of 30 chicks were kept as uninoculated controls. Chicks were observed daily for clinical signs and mortality. All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI). Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI. Gross lesions were recorded and selected tissues were collected for histopathology. The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S. pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin. Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23. Variable mortality was evident in groups inoculated with the lower dose of salmonella. The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups. The lower mean body weights were present in all treatment groups compared with uninoculated controls. No illness or mortality was observed in uninoculated control groups.     

Effect of ochratoxin A on Escherichia coli-challenged broiler chicks

A study was conducted to evaluate the effects of ochratoxin A (OA) on Escherichia coli-challenged broiler chickens. Day-old broiler chicks were separated into two groups of 92 chicks each, with one group fed a control mash diet, and the other fed a mash diet containing 2 ppm OA. On day 14, each group was further separated into two groups, with one group inoculated with E. coli O78 (1 x 10(7) colony-forming units/0.5 ml), whereas the other group was not inoculated with E. coli. After E. coli inoculation on day 14, four birds from each group were euthanatized at 1, 2, 3, 5, 7, 10, 14, and 21 days postinoculation. Escherichia coli infection caused dullness, depression, huddling, and diarrhea. Mortality was 14.3% in chicks infected with E. coli but fed no OA. Mortality increased to 35.7% in chicks fed OA and infected with E. coli. Decreased body weight and reduced feed intake were observed in chicks fed OA, and the effects were more pronounced in chicks fed OA and infected with E. coli. Increased serum levels of aspartate aminotransferase, alanine aminotransferase, uric acid, and creatinine and decreased levels of total proteins, albumin, globulins, calcium, and phosphorus were observed in OA-fed birds. Escherichia coli infection did not cause significant alteration in any of the serum biochemical parameters. The presence of OA in poultry rations increased mortality and the severity of an E. coli infection.