-
[show abstract]
[hide abstract]
ABSTRACT: Page 274 in the Scandinavian Journal of Immunology
SSI13-1018
Colonization Resistance and
Immunological Differences in Response to
An Experimental Salmonella Infection
between Two Chicken Lines Selectively
Bred for High or Low Concentration of
Mannose-Binding Lectin
S. L. Ulrich-Lynge1*, T. S. Dalgaard1, L. R. Norup1,
J. E. Olsen2 & H. R. Juul-Madsen1
1Animal Science, Aarhus University, Tjele, and 2Veterinary Disease Biology,
University of Copenhagen, Copenhagen, Denmark
Background: Mannose-binding lectin (MBL) is a key
protein in innate immunity. MBL works directly as an
opsonin or by initiating complement activation via the
lectin-dependent pathway. It has a high binding-affinity
for mannose and other sugar residues present on the surface
of many viruses, parasites and bacteria. In humans it has
been shown that MBL is associated with several infectious
diseases. In commercial poultry flocks, Salmonella enterica
infections can cause substantial problems despite vaccination,
use of antibiotics and prophylactic measures. Thus,
selection for more resistant chickens can be considered as an
alternative solution to decrease the occurrence of infection.
In vitro studies have shown that chicken (c)MBL is able to
bind a variety of Salmonella C1 serotypes, among these
S. enterica serotype Infantis [1].
Objectives: To investigate how an oral infection (1.0–
1.25*10E8 CFU per bird) with S. infantis S.123443 affects
day-old chickens from two selected lines L10H and L10L,
which differ in cMBL serum concentration.
Methods: Hundred and twenty animals were used in this
study; (34 in each infection group and 26 in each control
group, both L10L and L10H). Bodyweight was measured
throughout the experiment. Salmonella counts were performed
on cloaca swabs. Cell differentiation was determined
using whole blood flow cytometry.
Results: The daily bodyweight increase was on average
higher for the L10H animals than for the L10L animals,
regardless of infection. Salmonella was detected in cloaca
swabs from infected chickens in both lines and counts were
higher in L10L than L10H on day 4 and 19 pi, but not at
other time points. The absolute count of lymphocytes and
monocytes in peripheral blood differed between the two
chicken lines. In infected chickens higher numbers of
monocytes were observed on day 12 pi. Furthermore,
distribution of heterophil cells tended to differ at day 5 pi,
and thrombocytes at day 12 and 27 pi between the two
chicken lines independent of infection.
Conclusions: The present study indicates that genetic
selection for high cMBL levels in chickens may have an
effect on the robustness of the chicken in general, e.g. with
regard to the bodyweight. Prior studies have shown that
cMBL binds to the strain used in this study in vitro. Results
from the present study indicate that the cMBL level may
affect the magnitude of Salmonella colonization in day-old
chicken, but further studies are needed to confirm this.
References:
[1]. S. L. Ulrich-Lynge, T. S. Dalgaard, L. R.
Norup, J. E. Olsen, H. R. Juul-Madsen (2012).
The binding ability of purified chicken Mannose-
Binding Lectin (cMBL) to Salmonella enterica serotype
B, C1 and D. AIRG 2012: Scientific Programme and
Abstracts Edinburgh, UK, The University of Edinburgh,
The Roslin Institute.
Disclosure of Interest: None Declared.
Scandinavian Society of Immunology, Copenhagen; 04/2013
-
[show abstract]
[hide abstract]
ABSTRACT: Twelve-week-old indigenous chickens, either immune-suppressed using dexamethasone (IS) or non-immune-suppressed (NIS), were challenged with a low virulent strain, Pasteurella multocida strain NCTC 10322(T), and developed clinical signs and pathological lesions typical of chronic fowl cholera. NIS birds demonstrated much more severe signs of fowl cholera than IS birds. With few exceptions, signs recorded in IS and NIS birds were of the same types, but significantly milder in the IS birds, indicating that immune suppression does not change the course of infection but rather the severity of signs in fowl cholera. P. multocida signals by fluorescent in situ hybridization (FISH) were observed between 1 h and 14 days in the lungs, trachea, air sacs, liver, spleen, bursa of Fabricius and caecal tonsils, while signals from other organs mostly were observed after 24 h. More organs had FISH signals in NIS birds than in IS birds and at higher frequency per organ. Many organs were positive by FISH even 14 days post infection, and it is suggested that these organs may be likely places for long-term carriage of P. multocida following infection. The present study has demonstrated the spread of P. multocida in different tissues in chickens and distribution of lesions associated with chronic fowl cholera, and pointed to a decrease of pathology in IS birds. Since dexamethasone mostly affects heterophils, the study suggests that these cells play a role in the development of lesions associated with chronic fowl cholera in chickens.
Avian Pathology 12/2011; 40(6):629-37. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Pasteurella multocida causes fowl cholera, a highly contagious and severe disease in chickens and water fowls. The disease is not well described in less intensive production systems, including scavenging family poultry production in developing countries. P. multocida was isolated from 25.9% of healthy-looking ducks and 6.2% of chickens from free-range family poultry farms and at slaughter slabs at market. On experimental infection with 1.2 to 2.0 x 10(8) organisms of the P. multocida type strain (NCTC 10322(T)), 12-week-old chickens expressed fowl cholera clinical signs significantly more times (372 signs) than those of 4-week-old, 8-week-old and 16-week-old chickens (173, 272 and 187 signs) and more signs were severe. In family ducks the 8-week-old birds expressed clinical signs significantly more times (188 signs) than those of the other age groups (117, 80, and 83 signs, respectively) and severe signs were more frequent. P. multocida transmitted from seeder birds (n=12) to sentinel birds (n=30), which developed clinical signs, and in some cases lesions of fowl cholera allowed bacterial re-isolation, whether infected ducks served as seeders for chickens or chickens served as seeder for ducks. This study has documented the occurrence of P. multocida among healthy-appearing family poultry in a tropical setting, and demonstrated that age susceptibility is highest in 12-week-old family chickens and 8-week-old family ducks when challenged with a low-virulent strain of P. multocida. It has further demonstrated that cross-transmission of fowl cholera may happen between family ducks and chickens, and vice versa.
Avian Pathology 03/2008; 37(1):51-7. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Investigations were conducted to determine the occurrence of Avibacterium paragallinarum in poultry in Uganda. A total of 710 each of bacteriologic and serum samples were taken from chickens and turkeys for demonstration of A. paragallinarum and antibodies. Samples for isolation of A. paragallinarum were also subjected to direct polymerase chain reaction (PCR) for demonstration of the organism's presence. Antibodies to A. paragallinarum were demonstrated in the sera using the hemagglutination inhibition test. A total of five isolates were recovered from two out of five commercial layer chicken farms investigated where suspected cases of infectious coryza were reported, and all of them belonged to Page's serovar C. PCR detected more positive samples (11/68) than did culture (5/68). Isolates were not recovered from free-range poultry nor were there any positive samples by PCR. The overall seroprevalence was 40.5% and the seroprevalence to serovars A, B, and C were 18%, 0.5%, and 22%, respectively. Antibodies to all Page's serovars A, B, and C were demonstrated in free-range chickens but only serovar C antibodies were demonstrated in commercial chickens. No antibodies were demonstrated in turkeys. This is the first time infectious coryza has been confirmed in Uganda and the causative agent, A. paragallinarum, isolated. A high seroprevalence observed in free-range chickens seems to indicate a subclinical infection under extensive village management conditions.
Avian Diseases 07/2007; 51(2):534-9. · 1.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Avibacterium paragallinarum isolates from Uganda were characterized for their virulence by comparison of their pathogenicity and their resistance to serum. Pathogenicity was evaluated using commercial Hisex Brown layer chickens, local indigenous chickens, local turkeys and local guineafowls inoculated with 108 colony-forming units of Av. paragallinarum and comparing their overall mean disease scores over a period of 20 days. Persistence of the bacteria in the host and water was also investigated for a 60-day period by culture and polymerase chain reaction as well as use of sentinel chickens. Serum resistance was measured by comparison of the growth kinetics and survival indices at 3 and 6 h. There was no difference in the virulence of the isolates. Commercial layer chickens and local indigenous chickens were equally susceptible to challenge, while turkeys and guineafowls only showed transient mild signs and did not transmit infection. Turkeys and guineafowls did not acquire the infection when placed in contact with infected chickens. The isolates were resistant in normal chicken serum at both 3 and 6 h of incubation but were resistant at 3 h and sensitive at 6 h in turkey and guineafowl sera. The resistance of the isolates to serum correlated with their pathogenicity in the different hosts. No carrier status was demonstrated in this study using polymerase chain reaction and culture. The present study demonstrates that Ugandan Av. paragallinarum isolates are pathogenic to chickens with only transient signs in turkeys and guineafowls, and that serum resistance could be a subject for further investigation as a predictor of virulence of these bacteria. The role of turkeys and guineafowls in transmission of Av. paragallinarum was not demonstrated in the present investigation.
Avian Pathology 03/2007; 36(1):35-42. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Salmonella Typhimurium DT 104 is generally assumed to be spread by contact between live animals, e.g. by trading. The aim of the present study was to assess the importance of other routes of transmission in the dissemination of this bacterium.
An outbreak among 14 cattle and pig herds located in a geographically narrow area in Denmark was investigated. Epidemiological information and disease history of the herds was obtained through interviews. Based on this, the hypothesis for horizontal spread was proposed, and these were confirmed by comparison of the pulsed field gel electrophoresis (PFGE) and the plasmid profiles of isolates obtained by continuous sampling over a period of almost 3 years.
The study indicated that other routes might play an important role, than the trading of live animals, in the spread of S. Typhimurium DT 104 among livestock.
Salmonella Typhimurium DT 104 infected herd might pose a significant risk to herds located within the same geographic area. In advising on how to avoid the spread of this bacterium, factors like person contacts, sharing of equipment and contaminated slurry should be focussed on in addition to infected animals.
Journal of Applied Microbiology 11/2006; 101(4):883-90. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate if taxon 42 of Bisgaard isolated from pigs represents genuine [Pasteurella] caballi, which was previously only isolated from horses.
A total of 15 field isolates from horses and pigs from five different countries representing three continents were subjected to extended phenotypical characterization. Although minor differences were observed between taxon 42 and [P.] caballi, these differences did not allow phenotypic separation. Ribotyping based on HindIII digestion showed five profiles based on nine band positions. One [P.] caballi strain and two taxon 42 strains shared the same profile. Ribotyping using HpaII gave a higher diversity with nine profiles based on ten band positions. While no profiles were shared between the taxon 42 and [P.] caballi strains, pattern analysis showed that two of the taxon 42 isolates were most similar (91% similarity) with a [P.] caballi isolate. The 16S rRNA gene sequencing of one strain of taxon 42 and one strain of [P.] caballi was performed and compared with the published sequence for the type strain of [P.] caballi. The three strains showed nearly identical sequences with at least 99.8% similarity. DNA re-associations measured by the micro-well method were 79 and 77%, respectively between the type strain of [P.] caballi and two strains of taxon 42 representing distinct ribotypes and confirmed that taxon 42 belongs to [P.] caballi.
The present investigation documents that [P.] caballi can be isolated from clinical respiratory specimens from pigs and the recognized association with respiratory infections in horses and horse bite infection in humans. Strains classified as taxon 42 are [P.] caballi isolated from pigs and for both pigs and horses, lesions mainly include the respiratory tract.
The results will improve the diagnostics and progress studies of virulence and epidemiology of [P.] caballi.
Letters in Applied Microbiology 11/2006; 43(4):424-9. · 1.62 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A study was conducted to evaluate the disease resistance potential in 105 chickens of six indigenous local chicken ecotypes in Tanzania by orally challenging 1-week-old chicks with 2.5 x 10(8) colony-forming units of virulent S. Gallinarum. For 14 days post infection, clinical signs, necropsy findings, antibody titres, packed cell volume, leukocyte population count, and viable bacterial cell counts in the liver and spleen were recorded. Clinical signs were recorded daily but other parameters were recorded on the day of infection, then on days 3, 6, 10 and 14 after infection. Clinical signs of fowl typhoid were evident in chickens from day 3 post infection and disappeared by day 9 post infection. Pathological lesions on sacrificed birds included enlargement of the liver and spleen with foci of necrosis on the liver, spleen and myocardium. The mean viable bacterial cell counts in the liver and spleen varied between ecotypes, although the differences were not statistically significant. There were significant differences in the leukocyte population in the peripheral blood, with one ecotype (Morogoro-medium) showing a consistent and significantly higher heterophil count compared with other ecotypes. It was concluded that there is a selectable resistance potential to S. Gallinarum among the local chicken ecotypes in Tanzania that may be attributable to non-specific host immune responses. Further studies are suggested.
Avian Pathology 09/2006; 35(4):270-6. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Listeria organisms are documented to be zoonotic; one of the sources of infection is the domestic fowl where it could occur as in apparent infection. The carriage of Listeria monocytogenes and other Listeria in indigenous birds has not been documented in Kenya.
To establish whether healthy looking indigenous chickens and ducks could be carriers of Listeria monocytogenes and other Listeria species.
Field survey of indigenous chickens and ducks in three districts of Kenya.
Embakasi and Dagoreti divisions in Nairobi district; Athi river division in Machakos district; and Ngong division in Kajiado district, in Kenya.
One hundred and thirty six indigenous chickens and 39 ducks reared under free range scavenging system in Nairobi, Machakos and Kajiado districts, in Kenya, were sampled.
In surveying the birds, the cloacal and pharyngeal swabs were taken from each bird separately using sterile cotton--tipped applicator swabs. The swabs in saline were transported in a coolbox to the laboratory for bacterial isolation and characterization.
None (only compared farmed and the traded birds).
Isolation of Listeria species and pathogenicity of Listeria isolates.
Two Listeria monocytogenes and seven other Listeria species were recovered from the oropharyngeal swab samples of farm and market chickens but none from respective cloacal swabs. No Listeria was recovered from either oropharyngeal or cloacal swabs of farmed duck and slaughter chickens. Traded chickens yielded more Listeria isolates as compared to farmed chickens.
This study shows that indigenous chickens in Kenya are carriers of Listeria monocytogenes and other Listeria species.
East African medical journal 11/2004; 81(10):529-33.
-
[show abstract]
[hide abstract]
ABSTRACT: Resistance of bacteria to antibiotics and disinfectants has been reported widely in the world. Listeria monocytogenes is no exception, although normally it tends to be variably sensitive to many antibiotics and disinfectants.
To assess the susceptibility of Listeria isolates recovered from indigenous chickens to commonly used antimicrobials.
Nine Listeria isolates recovered from village chickens were tested for sensitivity to commonly used antibiotics and disinfectants and compared with Listeria monocytogenes type strains (L028 and DGH), Staphylococcus aureus NCTC 6571 and Escherichia coli ATCC 25922.
Nine Listeria isolates.
None.
Susceptibility to eight antibiotics and seven disinfectants.
The nine Listeria isolates were sensitive to gentamycin (100%), kanamycin (88.9%), tetracycline (77.8%), cotrimoxazole (66.7%), chloramphenicol (66.7%) and resistant to ampicillin, augmentin and cefuroxime. There was no difference between the antibiotic sensitivity to the various Listeria isolates and Listeria monocytogenes type strains (P > 0.05). The isolates were sensitive to disinfectants; A (100%), B (88.9%), D (77.8%), E (77.8%) but resistant to, CF, and G. There was significant difference between the resistance of Listeria isolates to the various disinfectants at the varied dilutions and the resistance at the recommended user--dilution (P < 0.00293).
This study has shown that some of the Listeria isolates were resistant to most common antimicrobial agents except gentamycin and disinfectant A. Hence the need to consider this resistance pattern for effective treatment and control of listeriosis.
East African medical journal 10/2004; 81(10):534-7.
-
[show abstract]
[hide abstract]
ABSTRACT: Characterization and classification of members of Pasteurellaceae isolated from birds by extended phenotypic characterization and 16S rDNA gene sequence comparison.
A total of 95 avian isolates were subjected to extended phenotypic characterization. Thirteen bacterial strains selected from main phenotypic clusters and isolated from parrot, parakeet, budgerigar, partridge, pheasant, chicken, duck, hawk and gull were subsequently characterized by 16S rDNA gene sequencing. Eight of the sequenced strains were classified with six taxa of Bisgaard of which two (34 and 40) have not been published before, and the properties of four others (14, 22, 26 and 32) changed upon the characterization of these new isolates. Of the remaining strains, one was identified as a phenotypic variant in maltose and dextrin of Pasteurella gallinarum another as a trehalose positive variant of taxon 3 of Bisgaard. The remaining three strains sequenced were not closely related to existing taxa of Pasteurellaceae. However, they were found to belong to the Avian cluster with 92-97% 16S rDNA gene sequence similarity.
The study allowed the classification of bacteria isolated from birds by the integrated use of extended phenotypic characterization and 16S rDNA gene sequence analysis. Only the application of 16S rDNA gene sequencing allows a correct identification of variant strains.
The description of new taxa within the bacterial family Pasteurellaceae will subsequently allow additional isolates of these taxa to be identified and improve the diagnosis and epidemiological understanding of bacteria causing disease in birds.
Journal of Applied Microbiology 02/2003; 95(2):354-63. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate contamination of surfaces on a poultry slaughter line from infected poultry and subsequent cross-contamination of non-infected poultry.
A broiler slaughterhouse was investigated for the presence of Salmonella on 17 defined points over two 1-week periods. Flocks supplied to slaughter and neck skin samples from processed chicken were likewise investigated. Salmonella was detected in 10 out of 18 flocks at ante-mortem inspection, while seven flocks tested positive in the finished products. Equipment at all but one control point at the slaughter line tested positive at least once during the study. The chicken receiving area was the most contaminated. By comparison of typing results from serotyping, plasmid profile typing and phage typing, direct evidence for cross-contamination with Salm. serotype Typhimurium, Salm. Serotype 4.12:b:- and Salm. serotype Virchow on the slaughter line was obtained for four of the flocks. The cleaning procedure in place did not remove all Salmonella from the contaminated areas.
Evidence for contamination of equipment on a slaughter line and subsequent cross-contamination to non-infected chicken was provided by typing methods.
This study has provided detailed information on cross-contamination on a slaughter line by the use of phage typing and plasmid profiling. The study stresses the importance of controlling Salmonella in the primary production, as contamination of the equipment on the slaughter line will act as a vehicle to contaminate finished products. Cleaning procedures on slaughter lines cannot be expected to control this problem with the current equipment.
Journal of Applied Microbiology 02/2003; 94(5):826-35. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The productivity of local chickens under village management conditions was studied in six villages situated in three climatic zones within Morogoro District in Tanzania. Two villages were picked in each climatic zone (warm and wet, warm and dry, cool and wet) for the study. The data were obtained by actual measurement, qualitative observations and interview of members of the households directly responsible for the care of chickens. In addition, data sheets were given to selected farmers to record the performance of their chickens. The mean flock size for the three zones was 16.2, with a range of 2 to 58. The overall mean clutch size, egg weight and hatchability were 11.8, 44.1 g and 83.6%, respectively. The overall mean chick survival rate to 10 weeks of age was 59.7%. The mean live weights for cocks and hens were 1948 g and 1348 g, respectively. The mean growth rates to the age of 10 weeks were 4.6 g/day and 5.4 g/day, while those from 10 to 14 weeks of age were 8.4 g/day and 10.2 g/day for female and male birds, respectively. The age at first lay ranged between 6 and 8 months, and the average hen had three laying cycles per year. Most of the chickens were left to scavenge during the day and were provided with simple housing at night (95.2% of the owners). Only small amounts of supplementary feeds were occasionally given and minimal health care was provided. It was concluded that the low productivity of chickens was partly due to the prevailing poor management practices, in particular the lack of proper health care, poor nutrition and housing.
Tropical Animal Health and Production 10/2002; 34(5):405-16. · 1.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Components of the ATP-dependent Clp protease complex are found in a wide range of prokaryotic cells and they are often expressed as part of the cellular stress response. To investigate the physiological role of the proteolytic subunit, ClpP, in Salmonella enterica serovar Typhimurium (S. typhimurium) an in-frame deletion of the clpP gene was constructed. Growth experiments revealed that clpP is important for the ability of S. typhimurium to grow under various stressful conditions, such as low pH, elevated temperature and high salt concentrations. Since the stationary-phase sigma factor, RpoS, is a target of the Clp proteolytic complex, the effect of the clpP deletion in the absence of RpoS was examined; it was observed that growth of the S. typhimurium clpP mutant is affected in both an RpoS-dependent and an RpoS-independent manner. Analysis of the degradation of abnormal puromycyl-containing polypeptides showed that ClpP participates in the proteolysis of such proteins in S. typhimurium. These findings prompted an investigation of the growth of an Escherichia coli clpP mutant under various stress conditions. The growth of this E. coli mutant was affected by heat, salt and low pH, although not to the same extent as observed for the S. typhimurium clpP mutant. The results of this study indicate that the S. typhimurium clpP mutant is generally more sensitive to environmental stress than the E. coli clpP mutant and it is proposed that this is due to a reduced ability to degrade misfolded proteins generated under these conditions.
Microbiology 10/2002; 148(Pt 9):2727-33. · 3.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The pathogenicity of a virulent strain of Salmonella gallinarum was studied in local chickens and commercial layers. Sixty 4-month-old chickens were used. Of these, 50 chickens were orally infected with S. gallinarum, comprising 25 commercial layers and 25 local chickens. Five chickens in each group were used as uninfected negative controls. The clinical signs and pathological features of acute, subacute and chronic fowl typhoid were observed in both groups. Chickens in both groups seroconverted, but the antibody titre was significantly higher (p < 0.001) in the commercial layers. The antibody titre remained high to the end of the experiment in all the surviving chickens. Only one commercial layer chicken died during the course of the experiment. The PCV decreased significantly (p < 0.001) in the infected chickens of both groups as compared to the controls. The viable cell count of S. gallinarum in the liver and spleen reached a maximum on day 9 after infection in both groups. However, there was a significantly higher cell count (p < 0.05) in the commercial layers. The severity of the disease appeared to be slightly greater in the commercial layers, although the susceptibility was similar in both groups. It was concluded that, under experimental conditions, local chickens are just as susceptible to S. gallinarum infection as are commercial layers.
Tropical Animal Health and Production 05/2002; 34(3):195-204. · 1.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The pathogenicity of a virulent strain of Salmonella gallinarum was studied in local chickens and commercial layers. Sixty 4-month-old chickens were used. Of these, 50 chickens were orally infected with S. gallinarum, comprising 25 commercial layers and 25 local chickens. Five chickens in each group were used as uninfected negative controls. The clinical signs and pathological features of acute, subacute and chronic fowl typhoid were observed in both groups. Chickens in both groups seroconverted, but the antibody titre was significantly higher (ppS. gallinarum in the liver and spleen reached a maximum on day 9 after infection in both groups. However, there was a significantly higher cell count (pS. gallinarum infection as are commercial layers.
Tropical Animal Health and Production 04/2002; 34(3):195-204. · 1.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 1. A total of 144 chickens purchased from peasants in Morogoro, Tanzania were slaughtered, their crops dissected and the contents analysed. The birds consisted of 48 chickens from each of three climatic zones (warm and wet, warm and dry, cool and wet). Seventy-two chickens were slaughtered in each season, that is short rainy and long rainy season. 2. Cereal grains, bran, green forages, insects/worms and kitchen food wastes were the main crop contents and their composition varied significantly with season and climate. 3. The overall mean chemical compositions (g/kg) of the crop contents were: 430.8 +/- 107.78 dry matter (DM), 104.4 +/- 43.47 crude protein (CP), 61.2 +/- 36.48 ether extract (EE), 58.2 +/- 26.29 crude fibre (CF), 125.4 +/- 58-27 ash, 6.3 +/- 5.19 calcium (Ca) and 3.6 +/- 2.41 phosphorus (P). 4. CP, EE, ash and P contents varied significantly (P<0.05) with season but contents of DM, CF and Ca were not significantly different. 5. CP content was significantly higher (P<0.05) in growers than in adults while the reverse was true for Ca content. Other variables did not differ significantly. 6. Significant differences (P<0.05) in chemical composition were observed among the zones in all parameters except for CP content. 7. The study showed that the chemical composition of feeds eaten by rural scavenging chickens was below the nutritional requirements and varied with season, climate and age of birds.
British Poultry Science 04/2002; 43(1):64-9. · 1.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of the present study was to compare the invasion of selected zoonotic Salmonella serotypes of poultry in an in vivo chicken intestinal loop model and also in vitro in epithelial cell cultures. Invasion was measured relative to a reference strain, Salmonella Typhimurium 4/74 invH201::TnphoA. Two serotypes demonstrated intracellular log(10) counts that differed significantly from all other serotypes tested: Salmonella Enteritidis PT4 being 1.5 log(10) colony forming units (CFU) (31-fold) higher, and Salmonella Tennessee being 0.7 log(10) CFU (fivefold) lower than the reference strain (P < or = 0.0001). A group of serotypes, which can be vertically transmitted, showed significantly higher intracellular counts (fourfold to eightfold) than the reference strain. The group included S. Typhimurium 4/74, S. Typhimurium DT104 (poultry and porcine isolates), S. Enteritidis PT1, S. Enteritidis PT6, S. Enteritidis PT8, and Salmonella Berta. The serotypes Salmonella Hadar, Salmonella Virchow, S. 4,12:b:-, S. Typhimurium DT41, and Salmonella Infantis, most of which are considered horizontally transmitted, did not show significantly different intracellular counts from the reference strain. Results from the cell culture invasion studies agreed with the in vivo data, with the exception of S. Berta and the poultry isolate of S. Typhimurium DT104.
Avian Pathology 03/2002; 31(1):41-7. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The productivity of local chickens under village management conditions was studied in six villages situated in three climatic zones within Morogoro District in Tanzania. Two villages were picked in each climatic zone (warm and wet, warm and dry, cool and wet) for the study. The data were obtained by actual measurement, qualitative observations and interview of members of the households directly responsible for the care of chickens. In addition, data sheets were given to selected farmers to record the performance of their chickens. The mean flock size for the three zones was 16.2, with a range of 2 to 58. The overall mean clutch size, egg weight and hatchability were 11.8, 44.1 g and 83.6%, respectively. The overall mean chick survival rate to 10 weeks of age was 59.7%. The mean live weights for cocks and hens were 1948 g and 1348 g, respectively. The mean growth rates to the age of 10 weeks were 4.6 g/day and 5.4 g/day, while those from 10 to 14 weeks of age were 8.4 g/day and 10.2 g/day for female and male birds, respectively. The age at first lay ranged between 6 and 8 months, and the average hen had three laying cycles per year. Most of the chickens were left to scavenge during the day and were provided with simple housing at night (95.2% of the owners). Only small amounts of supplementary feeds were occasionally given and minimal health care was provided. It was concluded that the low productivity of chickens was partly due to the prevailing poor management practices, in particular the lack of proper health care, poor nutrition and housing.
Tropical Animal Health and Production 01/2002; 34(5):405-416. · 1.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: From 1990 to 2000, the number of published named taxa based upon new isolates at species and genus levels in International Journal of Systematic and Evolutionary Microbiology, formerly International Journal of Systematic Bacteriology, have increased by approximately four- and sevenfold, respectively. New taxa based upon characterization of only a single isolate remained at around 40% for both categories. The Bacteriological Code (1990 Revision) has no recommendations on the number of strains required for definition of new taxa. For a few groups, a minimum number of 5-10 strains has been suggested in minimal standards. Since an exponential increase in new taxa can be expected in the future, the authors discuss problems related to naming new species and genera based upon descriptions of a single isolate and suggest that this practice is re-evaluated. It is proposed that the following should be added to Recommendation 30b of the Bacteriological Code: 'Descriptions should be based on as many strains as possible (minimum five), representing different sources with respect to geography and ecology in order to be well characterized both phenotypically and genotypically, to establish the centre (from which the type strain could be chosen) and the extent of the cluster to be named. In addition, comparative studies should be performed, including reference strains that represent neighbouring species and/or genera, in order to give descriptions that are sufficiently detailed to allow differentiation from these neighbours.'
International journal of systematic and evolutionary microbiology 12/2001; 51(Pt 6):2221-5. · 2.27 Impact Factor
