The complement fixation test for the diagnosis of Brucella ovis infection in rams

Complement fixation tests using three B. ovis antigen preparations in warm fixation tests (WCFT) and cold fixation (CCFT) tests were done on 541 ram sera. Semen samples from the same rams were examined culturally to identify B. ovis excretors. The CCFT, using an antigen prepared by heat extraction of B.ovis cells, had a sensitivity of 97% in 124 rams which were shedding B.ovis. The specificity was 99% in 144 rams from non-infected flocks. Seventy-seven per cent of 156 rams which reacted to this test were shedding B. ovis in their semen. Tests with other antigens were inferior in sensitivity and/or specificity. The WCFT gave lower titres than CCFT. Vaccination caused large numbers of false positive reactions in 4 flocks.     

Effect of Lonicera japonica extract on Mycoplasma gallisepticum in naturally infected broiler flocks

1. In this study, the effect of chlorogenic acid extract from Lonicera japonica Thunb. on Mycoplasma gallisepticum infections and the performance of broiler flocks was investigated.

2. A total of 360 Ross-308 broiler chicks taken from M. gallisepticum seropositive flocks were divided equally into three groups designated as control (nothing administered), antibiotic (Tylosin tartrate given for the first 3 d and d 20–22) and test group (chlorogenic acid extract given twice a day on d 16 and 22).

3. Broiler performance analysis, serological tests (slide agglutination), molecular identification (polymerase chain reaction) and histopathological examination were performed to detect M. gallisepticum.

4. The results show that chlorogenic acid not only increases live body weight but is also an alternative treatment option in M. gallisepticum–infected broiler flocks.

     

Natural zeolites in diet or litter of broilers

1. This study aims to analyse the influence of adding natural zeolites (clinoptilolite) to the diet or litter of broilers and their effects on growth performance, carcass yield and litter quality.

2. Three consecutive flocks of broilers were raised on the same sawdust litter, from d 1 to d 42 of age, and distributed in three treatments (control with no added zeolites, addition of 5 g/kg zeolite to diet and addition of 100 g/kg zeolites to litter).

3. The addition of zeolites to the diet or litter did not affect growth performance or carcass yield.

4. The addition of zeolites to the diet did not influence moisture content of the litter, ammonia volatilisation was reduced only in the first flock and pH of litter was reduced in the second and third flock.

5. However, the addition of zeolites to the litter reduced moisture content, litter pH and ammonia volatilisation in all flocks analysed.

6. The addition of 5 g/kg zeolite to the diet in three consecutive flocks was not effective in maintaining litter quality, whereas the addition of 100 g/kg natural zeolites to sawdust litter reduced litter moisture and ammonia volatilisation in three consecutive flocks raised on the same litter.

     

A longitudinal observational study of Salmonella shedding patterns by commercial turkeys during rearing and fattening,showing limitations of some control measures

1. The onset and progression of Salmonella infections was investigated in commercial turkey flocks from placement at 1 d old until slaughter in “brood and move” systems using a longitudinal observational approach based on faeces and environmental sampling with subsequent culture of Salmonella.

2. Persistent Salmonella Newport contamination was found within rearing houses and on their external concrete aprons after cleaning and disinfection between crops of heavily shedding young birds.

3. Salmonella shedding was often detected by 5 d of age and the frequency of positive samples peaked at 14–35 d. Thereafter Salmonella isolations declined, especially in the later (fattening) stages. Samples were still Salmonella-positive at low prevalence in half of the intensively sampled houses at slaughter age.

4. A number of management interventions to combat Salmonella infection of flocks, including sourcing policy, competitive exclusion cultures and cleaning and disinfection, were inadequate to prevent flock infection, although improved disinfection on one unit was associated with a delay in the onset of flock infection.

     

E-nose identification of Salmonella enterica in poultry manure

1. A DiagNose II electronic nose (e-nose) system was tested to evaluate the performance of such systems in the detection of the Salmonella enterica pathogen in poultry manure.

2. To build a database, poultry manure samples were collected from 7 broiler houses, samples were homogenised, and subdivided into 4 portions. One portion was left as is; the other three portions were artificially infected with S. enterica.

3. An artificial neural network (ANN) model was developed and validated using the developed database.

4. In order to test the performance of DiagNose II and the ANN model, 16 manure samples were collected from 6 different broiler houses and tested using these two systems.

5. The results showed that DiagNose II was able to classify manure samples correctly as infected or non-infected based on the ANN model developed with a 94% level of accuracy.

     

Changes in eggshell structure and predisposition of broilers to health problems: is there a common pathophysiology?

1. A study of broiler breeder eggs differing in eggshell matrix optical density was conducted to determine the association of eggshell structural quality and the risk of disease in broilers.

2. A total of 10 000 eggs from a broiler breeder flock were examined according to the pre-established criteria, and allocated to groups classified as having a high or low density shell matrix.

3. The eggs from respective groups were incubated and hatched in a commercial hatchery. Samples of unhatched eggs from each group were subjected to detailed examination to establish the cause of reproductive failure. First, quality chicks from each group were raised as separate flocks in a commercial broiler barn. Group performance, morbidity, and mortality were monitored throughout the growth period. All birds were processed in a commercial plant, and condemnation data were compiled.

4. There were significantly more unhatched eggs, and fewer quality chicks in the group classified as having a low density eggshell matrix, in comparison to the high-density group.

5. Embryo pathology accounted for a large proportion of the overall reproductive failure in both groups, with a large proportion of embryos showing anatomical anomalies. The eggs and embryos from the low-density eggshell matrix group were three times more likely to be infected.

6. Significantly higher production losses associated with mortality/morbidity, and condemnations of carcasses at processing were observed in broilers from the low-density eggshell group compared with the high-density eggshell group.

7. It is concluded that common metabolic/physiological changes in breeder hens associated with eggshell pathology may be also risk factors linked with predisposition of broiler chicks to some health problems.

     

Genetic variability of two Italian indigenous chicken breeds inferred from microsatellite marker analysis

1. The objective of this study was to determine the genetic structure and variability of Bionda Piemontese and Bianca di Saluzzo (Piedmont, Northwest Italy) using an international set of microsatellite loci (AVIANDIV-FAO). Differences compared with commercial lines and other Italian breeds were verified to justify the implementation of conservation programmes.

2. Flock contribution to genetic variability was assessed following the approach implemented in the MolKin software. Comparison was performed using the fixation index and the Reynolds genetic distance. The most likely number of different populations was estimated using the clustering procedure implemented in STRUCTURE.

3. The molecular information suggests that management practices could have prevented random mating and produced inbreeding and heterogeneity across flocks. In this respect, Bionda and Bianca show substructuring and are more similar to British breeds than other continental European breeds.

4. Bionda and Bianca fit into the European breeds provided with the highest number of alleles and expected heterozygosity. There is a clear distinction between the Piedmont breeds and the other populations. The Piedmont poultry differ from both commercial lines and other Italian breeds and retain a high level of genetic variability.

5. As for other indigenous breeds, Bionda and Bianca could make an original contribution to the industry in the future. A collective planned approach to restoration is essential, because the flocks are managed with poor regulation. Enhancing connection between breeders with an efficient replacement interchange and mating plan is the right way of controlling inbreeding, preventing substructuring and increasing variability within the flocks.

     

The spring-rise phenomenon: Seasonal changes in the worm burdens of breeding ewes and in the availability of pasture infection

Extract

A Mastitis control programme is essentially a biological regulatory system involving the three essential components of any control mechanism:

• A signal from a detector indicating departure from normality

• The interpretation of the signal (diagnosis)

• A feed-back signal to the origin of the detection signal indicating corrective action.

     

The hen's egg: Prediction and reduction of downgrading in large producer groups

British Egg Marketing Board data on the incidence of downgrading in eggs received at packing stations during the second week in each month from April 1960 to March 1968 have been analysed in relation to:

1. the incidence of free‐range, deep‐litter and battery husbandry in flocks from which they came, as estimated by interpolation from annual census data;

2. season, as represented by fundamental and first‐harmonic sine and cosine terms;

3. age‐structure of the flocks, as indicated by the incidence of extra‐small eggs 10 months earlier;

4. time;

5. packing‐station throughput.

It is shown that 93–3 per cent of the variance of downgrading percentage is associated with variation in (i), (ii) and (iii). After these effects had been taken into account there was no significant long‐term time‐trend but there were small effects associated with certain years. There was no significant effect of (v). The regression equation was used to predict the incidence of downgrading in the second week of each month from April 1968 to January 1969; this it did accurately except in May and June 1968, when the downgrading percentage fluctuated to an unprecedented degree following a very cold and a very hot spell of weather.

It is suggested that large producer‐packer groups should systematically collect information on the incidence of downgrading and the percentages of birds of each strain and age‐group, of cages of each type, of nutritional regimes and of egg‐collection methods; and that these data should be analysed to yield (a) forecasts of downgrading incidence and (b) estimates of the effect of each strain, cage‐type, etc. on downgrading incidence, for use when deciding replacement policy.     

Critical test evaluation of micronized mebendazole against Anoplocephala Perfoljata in the horse

Extract

More than half of the writer's group practice involves equine cases, mostly racehorses, and a large percentage of the surgery associated with them is orthopaedic. For this reason, and because a prosthetic technique requiring good surgical facilities has been used for surgical correction of laryngeal hemiplegia, an attempt was made to design and have constructed a unit which would fulfil the following :

2. A table of suitable size and strength with adequate padding.

3. The table to be elevated reliably to a comfortable operating height.

4. The elevation to be; rapid so that after induction of anaesthesia and elevation the horse would still be deeply anaesthetized enough to allow easy passage of the endotracheal tube.

5. A safe and efficient method to move the anaesthetized post-operative patient to a recovery room.

The capital and maintenance costs of the theatre had to be met by the returns from surgical fees and, to avoid increasing these significantly, the construction was carried out using facilities already available, and using only essential items.     

Post-mortem proteolysis and tenderisation are more rapid and extensive in female duck breast muscle

1. The post-mortem proteolysis and tenderisation between male and female duck breast muscles were compared.

2. The results showed that μ-calpain activity, desmin content and shear force decreased more quickly in female than in male samples stored at 5°C.

3. It is suggested that the post-mortem proteolysis and tenderisation are more rapid and extensive in female duck breast muscle.

     

Abusive use of antibiotics in poultry farming in Cameroon and the public health implications

1. The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined.

2. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics.

3. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined.

4. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities.

5. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues.

6. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested.

7. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

     

Investigation of laboratory testing issues in the context of the Salmonella National Control Programme in Great Britain

1. The objective of this study was to identify any issues arising during the laboratory testing of samples collected under the National Control Programme for Salmonella.

2. A questionnaire-based survey was conducted among Defra (Department for Environment, Food and Rural Affairs)-approved testing laboratories in order to identify any complicating factors that the laboratories may encounter during the processing of samples.

3. Samples were reported to arrive in good condition and within the specified time frame after collection. The only concern was that new clients may be unaware of the procedure or correct sampling consumables to use.

4. There was evidence of variability between laboratories regarding the sample testing procedure used, with deviation from the guidelines in some cases.

5. This finding suggests that further guidance for laboratories on methodology is likely to be beneficial as this could help improve the detection of low levels of Salmonella.

     

Prostaglandin responses in dairy herd breeding programmes

Abstract

A re-evaluation of results from ten trials conducted in commercial dairy herds between 1974 and 1981 in which lactating dairy cows were injected once or twice with either of two forms of prostaglandin F_2∞ (PGF) showed that:

• Key points

• ? the variation in the post-injection interval to oestrus was influenced by the stage of the oestrous cycle at which treatment was administered;

• ? this variation was suffkient to reduce pregnancy rates to set-time inseminations;

• ? an accurate aid for oestrus detection, such as tail painting, should be used routinely with PGF;

• ? if PGF-treated cows were detected in oestrus before being inseminated, the pregnancy rates to first insemination were usually 10% higher than in untreated herd mates.

The results show that PGF systems in dairy herds should not be used as au alternative to accurate oestrus detection. These systems can be used to condense the breeding programme and increase pregnancy rates to first insemination. The exnloitation of this fertility effect justifies the reassessment of PGF usage in New Zealand dairy herds.     

Agouti signalling protein (ASIP) gene: molecular cloning,sequence characterisation and tissue distribution in domestic goose

1. Agouti signalling protein (ASIP) is an endogenous antagonist of melanocortin-1 receptor (MC1R) and is involved in the regulation of pigmentation in mammals. The objective of this study was to identify and characterise the ASIP gene in domestic goose.

2. The goose ASIP cDNA consisted of a 44-nucleotide 5?-terminal untranslated region (UTR), a 390-nucleotide open-reading frame (ORF) and a 45-nucleotide 3?-UTR. The length of goose ASIP genomic DNA was 6176 bp, including three coding exons and two introns.

3. Bioinformatic analysis indicated that the ORF encodes a protein of 130 amino-acid residues with a molecular weight of 14.88 kDa and an isoelectric point of 9.73.

4. Multiple sequence alignments and phylogenetic analysis showed that the amino-acid sequence of ASIP was conserved in vertebrates, especially in the avian species.

5. RT-qPCR showed that the goose ASIP mRNA was differentially expressed in the pigment deposition tissues, including eye, foot, feather follicle, skin of the back, as well as in skin of the abdomen. The expression level of the ASIP gene in skin of the abdomen was higher than that in skin of the back.

6. Those findings will contribute to further understanding the functions of the ASIP gene in geese plumage colouring.

     

Lentivirus-mediated RNA interference of myostatin gene affects MyoD and Myf5 gene expression in duck embryonic myoblasts

1. The aim of this study was to construct lentivirus-mediated short hairpin RNA (shRNA) vectors targeting the duck MSTN gene and investigate whether these vectors can affect the development of duck primary cultured embryonic myoblasts.

2. MSTN mRNA levels in the myoblasts were detected using quantitative real-time polymerase chain reaction (PCR), cell proliferation was assessed by MTT assays and cell differentiation was assayed by photography.

3. MSTN mRNA levels in PLL3.7-MSTN-shRNA1, PLL3.7-MSTN-shRNA2 and PLL3.7-MSTN-shRNA3 lentivirus-mediated shRNA groups were reduced by 61.6%, 76.9% and 79.1%, respectively, compared to control cells.

4. Down-regulation of MSTN in duck embryonic myoblasts stimulated cell proliferation and inhibited differentiation, accompanied by a greater than twofold down-regulation of MyoD expression and up-regulation of Myf5 expression.

5. These results revealed that silencing of MSTN changes the development of duck embryonic myoblasts by regulating the expression level of MyoD and Myf5 genes.

     

Accelerated digestion of nucleic acids by pepsin from the stomach of chicken

1. Nucleic acids have become an important nutritional supplement in poultry feed; however, the digestion of nucleic acids in poultry is unclear. The objective of this study was to investigate the digestion of nucleic acids by chicken pepsin in vitro.

2. The extracted pepsinogen from the stomach of the chicken was purified to homogeneity. Upon activation at pH 2.0, chicken pepsinogen was converted to its active form.

3. Nucleic acids, including λ-DNA, salmon sperm DNA and single-strand DNA (ssDNA), can be used as substrates and digested into short-chain oligonucleotides by pepsin.

4. Interestingly, the digestion of the nucleic acids was inhibited when pepsin was treated by alkaline solution (pH 8.0) or pepstatin A. Also, the digestion of the nucleic acids was not affected by the addition of haemoglobin or bovine serum albumin.

5. The results suggested that nucleic acids could be digested by chicken pepsin. Thus pepsin may have a role in digesting nucleic acids in vivo. Nucleic acids added to poultry fed may be digested, starting from the stomach.

     

Evaluation of potential probiotic characteristics and antibacterial effects of strains of Pediococcus species isolated from broiler chickens

1. Pediococcus spp. were isolated from poultry rectum, faeces and food as good probiotic candidates in order to select strains to be used as probiotic in poultry feed.

2. A total of 168 lactic acid bacteria were isolated and 51 isolates including 31 Lactobacillus spp. and 20 Pediococcus spp. were able to survive in low pH and bile salt concentration. The Pediococcus spp. were identified and their ability to form biofilm, adhesion to Caco-2 cells and antimicrobial activities against enteric pathogenic bacteria were determined.

3. The results showed the presence of two strains, Pediococcus acidilactici P17 and P19 in rectal swab samples from 21-d old chickens with significant antibacterial activities against Salmonella enteritidis and Escherichia coli.

4. The results suggest that only a few isolates of Pediococcus with potential probiotic activities are present in the poultry industry.

     

Multilocus sequence analysis for Mycoplasma synoviae molecular genotyping

1. The aim of this study was to identify molecular techniques which enable clear discrimination between Mycoplasma synoviae isolates for improved epidemiology.

2. Multilocus sequence analysis (MLSA) of 6 M. synoviae loci was conducted for genotyping of isolates with previously determined 5?-vlhA sequences.

3. Sequencing of three polymorphic genes (5?-vlhA, cysP and nanH) enables good discrimination between isolates with different genotypes. Such a genotyping scheme revealed 10 distinct genotypes, which were confirmed by sequencing of an additional three loci of the M. synoviae genome. Epidemiologically linked strains formed clusters with the same genotypes which clearly differed between clusters.

4. MLSA used in this study is a promising tool for epidemiology of M. synoviae isolates, but it should be evaluated by further investigations using a much higher number of M. synoviae strains.