Pharmacokinetics of amoxicillin in broiler chickens

Amoxicillin was given to two groups of eight chickens at a dose of 10 mg/kg of body weight, intravenously (i.V.) or orally. Plasma concentration was monitored serially for 24 h after each administration. Concentrations of amoxicillin were measured using high-performance liquid chromatography. Pharmacokinetic variables were calculated, using a two-compartment open model. The elimination half-life, and the mean residence time for plasma were 8.17 +/- 0.31 and 10.46 +/- 0.51 h, respectively, after i.v. administration and 9.16 +/- 0.60 and 12.26 +/- 0.81 h, respectively, after oral administration. After single oral administration, amoxicillin was rapidly absorbed, with T(max), of 1.00 +/- 0.06 h. Maximum plasma concentration was 160.40 +/- 4.67 mug/ml and mean amoxicillin concentrations > 15 mug/ml persisted for 24 h. Oral bioavailability of amoxicillin was found to be 63.00 +/- 4.58%. The results indicate that a dosage of 10 mg/kg administered orally at 24 h intervals should be effective in treating a variety of systemic infections in poultry.     

Campylobacter species in broiler chickens

The incidence of Campylobacter spp. in broiler chickens in Northern Ireland was determined by examining three groups of birds. These included: (1)12 flocks of broilers monitored at regular intervals from their introduction into commercial units until the time of slaughter; (2) 21 batches of unsolicited birds submitted to the laboratory for postmortem examination; and (3) 13 batches of chicks under 36 hours old. Most birds became infected but Campylobacter spp. were not usually isolated during the first 2 weeks of life. C. jejuni biotype 1 was the predominant species isolated although C. coli and an atypical strain were also isolated. At least five distinct serotypes were present (Penner sero-types 1,3,5,9 and 11) of which serotypes 1 and 9 were most common. In birds older than 2 weeks of age, an association was sometimes observed between the sudden occurrence of wet litter and the presence of C. jejuni in all or the majority of the birds sampled. Infection of broilers under 2 weeks of age was accompanied by mortality.     

Maduramicin and tiamulin compatibility in broiler chickens

A total of 480 1-day-old Hybro broiler chickens were divided into five treatment groups (A: unmedicated control, B: maduramicin, C: maduramicin + tiamulin, D: monensin + tiamulin and E: tiamulin) to study the effect on performance parameters, organ weights, blood haematology and biochemistry, and histopathology of liver and selected striated muscles, when maduramicin at 5 parts/10(6) and monensin at 100 parts/10(6) were included in feed in starter and grower periods, and tiamulin 9 in water at 270 parts/10(6) the recommended therapeutic level, from day 28 to 31. Performance parameters were significantly and negatively affected by monensin but not by maduramicin after treatment with tiamulin. Histopathological examination of striated muscles showed no incompatibility of maduramicin + tiamulin, while lesions were found in the monensin + tiamulin treated group. It is concluded that the use of tiamulin to a therapeutic level for 3 consecutive days is compatible with the simultaneous presence of maduramicin in the feed of broilers.     

Staphylococcus simulans associated with endocarditis in broiler chickens

This report suggests a strong association between coagulase-negative Staphylococcus simulans and endocarditis in broiler chickens of a single flock. Clinical signs included increased mortality and lameness, and some dead chickens were found on their backs. Lesions included cauliflower-like, fibrinous vegetative lesions on the left atrioventricular valve; cream-coloured, necrotic foci of varying size in the liver; and necrosis of the femoral head. Histopathological examination of the heart revealed multifocal conglomerates of bacterial colonies attached to the valvular endocardium, threads of fibrin, and inflammatory cells with the presence of heterophils. S. simulans strains were first identified by API ID32, and then confirmed with Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry and by partial sequencing of the rpoB and dnaJ genes. These bacteria were resistant to methicillin but sensitive to vancomycin and characterized by slime production and protease activity.     

Systemic Mycoplasma synoviae infection in broiler chickens.

Systemic Mycoplasma synoviae infection in 47-day-old broiler chickens with septicaemic lesions and increased carcass condemnation rate is reported. The clinical history included respiratory signs and an enlarged keel bursa. Condemnations at the processing plant were due to airsacculitis and keel bursitis. Involvement of several organs, including the keel bursa, liver, spleen, brain, choroid of the eye, nerves and skeletal muscle associated with vasculitis, and the isolation of M. synoviae from the liver and keel bursa are only occasionally seen in field cases. Random amplified polymorphic DNA analysis of the M. synoviae isolated from the broiler chickens in this study had a different pattern when compared with the reference M. synoviae strains, WVU-1853, MS-H and F10-2AS, and another M. synoviae isolated from broiler breeders from the same company, but had a similar DNA pattern to an M. synoviae isolated from broiler chickens and turkeys owned by the same company. This finding suggests a horizontally acquired infection rather than vertical transmission.     

An unusual Clostridium colinum infection in broiler chickens

An unusual syndrome has been observed during the past two years in flocks of 12- to 25-day-old broiler chickens in Israel. The disease is characterized by enterotoxaemic-like signs including a high and sudden mortality, apathy, severe localized enteritis and nephrosis. C. colinum which is the causal agent of ulcerative enteritis has been the only bacteria consistently isolated from the affected chickens. The clinical and pathological findings in this syndrome are different from those reported for ulcerative enteritis.     

Isolation of Mycoplasma bovis from broiler chickens in Turkey

Mycoplasma bovis normally affects cattle, in which it causes pneumonia in calves, mastitis, arthritis and other diseases. In the present article we report the isolation of this bovine pathogen from the tracheas of broiler chickens with no clinical signs. The most probable source of infection was the cattle herd sharing the farm with the chickens.     

An outbreak of gangrenous dermatitis in commercial broiler chickens

The present report describes an outbreak of gangrenous dermatitis (GD) infection in a commercial poultry farm in Delaware involving 34-day-old broiler chickens. In addition to obvious clinical signs, some GD-affected broilers also showed severe fibrino-necrotic enteritis and large numbers of Gram-positive rods in the necrotic tissue. Histopathological findings included haemorrhage, degeneration and necrosis of parenchymatous cells, especially of skin, muscle, and intestine. Immunofluorescence staining revealed Clostridium-like bacilli in the skin and the intestine. Both Clostridium perfringens and Clostridium septicum genomic sequences were identified by polymerase chain reaction in bacterial cultures isolated from the skin, muscle, and intestine, and in the frozen tissues from the GD-affected birds. Serological analysis demonstrated that both affected and clinically healthy birds from the same house had high serum antibody titres against C. perfringens, C. septicum, Eimeria, chick anaemia virus, and infectious bursal disease virus. These results are discussed in the context of the relationship between the different Clostridium spp. and the pathogenesis of GD.     

Rupture of the right auricle in broiler chickens.

This report describes a case of cardiac right auricle rupture (RAR) in a flock of 11,500 broilers that were 14 days old. The birds were housed at an altitude of 300 m, with an external temperature of -10 degrees C and an internal temperature of 15 degrees C. There was 3.6% mortality, due to sudden deaths, from 10 to 14 days of age. All necropsied birds had haemopericardium due to RAR at the point of the junction with the vena cava, and 85% of them had blood in the oral cavity and external acoustic meatus. The vena cava and its caudal branches, the intestinal vessels, and the sinus durae matris and sinus saggitalis were distended. Histological examination showed haemorrhages into the myocardium, degeneration of the cardiac muscle fibres, as well as oedema of the lungs and hypertrophy of the smooth muscle bundles of the parabronchial walls. Blood in the mouth of the broilers may have been due to haemoptysis, which in humans is caused mainly by mitral stenosis. In broilers, mitral stenosis and/or insufficiency, and left ventricular failure with consequent pulmonary hypertension (PH) were considered as possible triggers for right ventricular failure. The alarm reaction in hypoxaemia, due to secondary factors such as cold, caused tachycardia and tachypnoea, may have induced further elevation of PH, and acute myocardial infarction causing cardiac rupture and haemopericardium in this case. Hypertension and PH, due to possible mitral stenosis/insufficiency in association with acute myocardial ischaemia, were probably the determinant factors causing this acute episode. This opens the possibility that the RAR may be cardiogenic.     

Proventricular hyperplasia (malabsorption syndrome) in broiler chickens

A syndrome has occurred in broilers over the past several years in widespread localities, including Georgia, Arkansas, and Texas. Poor feed conversion and delayed marketing are the principle clinical features. Lesions consist of enlargement of the proventriculus, gizzard erosion and dilatation, and decreased spleen and bursa size. Trichothecenes were demonstrated in the rations sampled at several broiler facilities. The clinical features and gross and microscopic changes observed in the field syndrome were duplicated by feeding chicks multiple combinations of a trichothecene mycotoxin (T-2 toxin) with histamines and diamines for 6 to 8 weeks.     

Growth enhancement in broiler chickens receiving CHEMEQRTM polymeric antimicrobial

This study investigated the use of CHEMEQ^RTM polymeric antimicrobial as a means of enhancing health and growth rates in broiler chickens. One-day-old Cobb-500 broilers were reared to 42 days. In trial 1, 100 birds received CHEMEQ^RTM polymeric antimicrobial via water, and 100 birds were untreated. Treated birds had significantly greater (P<0.0001) average daily gain (ADG), significantly lower (P<0.0016) feed conversion ratios, significantly lower (P<0.05) mortality, and a significantly lower (P<0.0042) viscosity of their ileal contents. In trial 2, three groups of 40 birds received reducing dosages of CHEMEQ^RTM polymeric antimicrobial, and a fourth group remained untreated. Groups receiving CHEMEQ^RTM polymeric antimicrobial had significantly greater (P<0.05) ADG, and two groups had significantly lower (P<0.05) feed conversion ratios than the controls. In trial 3, groups of 40 birds received either CHEMEQ^RTM polymeric antimicrobial, Salinomycin or Lasalocid in-feed, or were untreated. Birds receiving CHEMEQ^RTM polymeric antimicrobial had significantly greater (P<0.05) ADG than those receiving Salinomycin. CHEMEQ^RTM polymeric antimicrobial helped to maintain the health and to improve the growth performance of broiler chickens.     

Effect of garlic supplementation on complement activity in broiler chickens

Recent studies have demonstrated the potential immuno-modulatory activity of herbal products in human and animals. The present study was performed to elucidate the impact of including fresh garlic powder (FGP) in the diet of broiler chicks on serum alternative pathway of complement activation (APCA) activity, as a functional part of humoral innate immunity. For this, two hundred new-born chicks were divided into three groups: A (50 chicks), B and C (75 each). The chicks in group A were fed control diet, whereas those in groups B and C received diets supplemented with 1% or 3% of FGP, respectively. On day 21, half of the chicks in groups B and C were separated into groups D and E, respectively, and fed control diet afterwards. Sera were collected on days 1, 14, 21, 32 and 42, and assayed for APCA activity. The results showed that APCA activity in groups A and B increased up to day 32 and then decreased (P < 0.05). On day 21, the highest and lowest APCA activities (P < 0.05) were noticed in groups B and C, respectively. On days 32 and 42, group C had the least APCA activity, but the differences among other groups were not significant (P > 0.05). Furthermore, the removal of FGP from the diet led to the improvement of APCA activity in treated groups. In conclusion, garlic supplementation, depending on the rate and period of time used in the diet, may enhance or depress humoral innate immunity in broiler chickens.     

Immunization of broiler chickens against Clostridium perfringens-induced necrotic enteritis

Necrotic enteritis (NE) in broiler chickens is caused by Clostridium perfringens. Currently, no vaccine against NE is available and immunity to NE is not well characterized. Our previous studies showed that immunity to NE followed oral infection by virulent rather than avirulent C. perfringens strains and identified immunogenic secreted proteins apparently uniquely produced by virulent C. perfringens isolates. These proteins were alpha-toxin, glyceraldehyde-3-phosphate dehydrogenase, pyruvate:ferredoxin oxidoreductase (PFOR), fructose 1,6-biphosphate aldolase, and a hypothetical protein (HP). The current study investigated the role of each of these proteins in conferring protection to broiler chickens against oral infection challenges of different severities with virulent C. perfringens. The genes encoding these proteins were cloned and purified as histidine-tagged recombinant proteins from Escherichia coli and were used to immunize broiler chickens intramuscularly. Serum and intestinal antibody responses were assessed by enzyme-linked immunosorbent assay. All proteins significantly protected broiler chickens against a relatively mild challenge. In addition, immunization with alpha-toxin, HP, and PFOR also offered significant protection against a more severe challenge. When the birds were primed with alpha-toxoid and boosted with active toxin, birds immunized with alpha-toxin were provided with the greatest protection against a severe challenge. The serum and intestinal washings from protected birds had high antigen-specific antibody titers. Thus, we conclude that there are certain secreted proteins, in addition to alpha-toxin, that are involved in immunity to NE in broiler chickens.     

Experimental reproduction of the runting-stunting syndrome of broiler chickens

A model for the reproduction of the runting-stunting syndrome (RSS) of broiler chickens is described. In this model, groups of at least 90 day-old broiler chickens were inoculated (per os) with various tissue homo-genates or virus preparations. During the first week post-inoculation, birds were examined for the development of histopathological changes in their intestines. At day 14 post-inoculation, the remaining birds were weighed and tested for elevations in plasma amylase activity and examined for the development of pancreatic atrophy. Bacteria-free intestinal and pancreatic homogenates from chickens of different ages, taken from flocks which developed RSS, regularly induced a lower mean live-weight in treated birds. Of these, only intestinal homogenates prepared from 5-day-old birds induced intestinal lesions, lowered mean live-weight and increased the incidence of both elevated plasma amylase activity and pancreatic atrophy. These changes were more marked in birds exposed to short periods of sub-optimal temperatures during the first week post-inoculation. An ultracentri-fuged pellet prepared from this intestinal homogehate, was also found to induce an increased incidence of pancreatic atrophy in treated birds. These studies suggest that the causative agent(s) of RSS is an as yet unidentified virus, and that the effects of this infection are greater in birds subjected to stress, such as sub-optimal temperature exposure, within the first week of hatch.     

Functional comparison of heterophils isolated from commercial broiler chickens

Heterophils from two pure lines (A and B) of commercial broiler chickens were isolated on days 1, 4, and 7 post-hatch to evaluate their ability to (1) phagocytose Salmonella enteritidis (SE) (2) degranulate when exposed to immune-IgG opsonized SE, and (3) produce an oxidative burst. On days 1 and 4, heterophils from line A were functionally more efficient compared to heterophils from line B (p<0.05). By 7 days post hatch, heterophil functions for both lines were comparable. To further study the inheritance of heterophil functional efficiency, F1 reciprocal crosses (line C=male B×female A; line D=male A×female B) were evaluated for functional activity and compared with the immunologically efficient (A) and non-efficient (B) parent lines. Heterophils from line D had a more efficient heterophil function (p&lt;0.05) when compared to heterophils from C. These results suggest that heterophil function and efficiency can be genetically transferred to progeny. Moreover they indicate that heterophil function is sex-associated and genetically controlled by the rooster since progeny of line A males maintained immunologically efficient characteristics whereas heterophils from the progeny of line B roosters remained immunologically inefficient. To our knowledge, this is the first report to describe a functional relationship between pure and F1 reciprocal crosses of broiler chickens with regard to heterophils and the innate immune response.     

Studies on spondylolisthesis ("kinky back") in broiler chickens

Spondylolisthesis was diagnosed in paralyzed commercial broiler chickens using radiology. Six affected birds when held in a favourable environment recovered sufficiently to be used for breeding. Spinal deformation was still present in these birds when they were necropsied at one year of age. One hundred and sixty pedigreed chicks produced from these birds were raised intermingled with 151 commercial broilers. Six of the experimental chicks were clinically affected with spondylolisthesis while none of the control chicks were affected. In continued studies the experimental chicks were inbred and the control chicks randomly bred for a further two generations. In the second generation 13% of the experimental chicks were clinically affected with spondylolisthesis while in the third generation 9% were affected. Less than half a per cent of the control chicks from both second and third generations were affected. No consistent relationship between incidence of spondylolisthesis, hatch, brooding environment or ration was noted. A higher incidence of scoliosis was encountered in the experimental birds than in the control birds. No relationship between deformed legs and spondylolisthesis was apparent. The incidence of leg deformities was higher in the control than in the experimental birds.     

Concurrent cryptosporidiosis and chicken anaemia virus infection in broiler chickens

Concurrent infection with Cryptosporidium baileyi and chicken anaemia virus (CAV) was observed in a flock of 8000 4-week-old broiler chickens. The birds, showing overt symptoms of stunted growth and 25% mortality from hatching to 4 weeks of age, harboured the protozoan in the epithelial cells of the bursa of Fabricius and the urodeal portion of the cloaca. This is the first report on an outbreak of avian cryptosporidiosis associated with CAV.     

Cutaneous lesions in broiler chickens spontaneously affected with Marek's disease

A total of 91 8- to 9-week-old broiler chickens with Marek's disease (MD) skin tumours ("skin leukosis"), collected from 15 farms at the processing plants, were examined pathologically. Grossly, the skin lesions comprised various sizes and numbers of feather follicular nodules, which tended to fuse with each other as their size increased. Histologically, the lesions were classified into five types: type A was small lymphoid cell aggregates (LCA) consisting mostly of small lymphocytes with a few lymphoblasts and very rare mitotic figures; type B had large LCA consisting mainly of small lymphocytes with considerable numbers of lymphoblasts and very rare mitotic figures; type C was characterized by large coalesced LCA consisting almost equally of small lymphocytes and lymphoblasts with infrequent mitotic figures; type D exhibited very large coalesced LCA consisting mainly of lymphoblasts with some small lymphocytes and occasional mitotic figures; type E had very large coalesced LCA consisting almost completely of lymphoblasts with frequent mitotic figures. The histological MD cutaneous lesions were related to the size of gross skin nodules, the small feather follicular nodules consisted mainly of types B and C with type A, whereas large fused feather follicular nodules were composed mainly of types D and E. Nuclear inclusions were frequently found in the feather follicular epithelium in all skin nodules except for the largest fused ones. MD visceral lesions were more pronounced in birds having marked skin leukotic lesions. Feather pulp lesions (FPL) were more related to the visceral than the skin lesions; the constituent cells of FPL were compatible with those of the former lesions.