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.

     

Assessment of the effectiveness of head only and back-of-the-head electrical stunning of chickens

1. The study assesses the effectiveness of reversible head-only and back-of-the-head electrical stunning of chickens using 130–950 mA per bird at 50 Hz AC.

2. Three trials were conducted to compare both stunning systems: (a) behavioural assessment of return of consciousness, (b) insensibility to thermal pain, and (c) assessment of return of brain activity with visually evoked potentials (VEPs).

3. Assessment of behaviour suggested that the period of unconsciousness following head-only electrical stunning was shorter in hens compared to broilers.

4. Stunning across the back-of-the-head delayed the time to return of brainstem function compared to stunning with standard head-only electrodes. Additionally, back-of-the-head stunning produced a more prolonged period of electroanalgesia compared to head-only.

5. Based on examination of return of brain function with VEPs in hens, back-of-the-head stunning produced a shorter-lasting stun than standard head-only. However, even for standard head-only, the stun was notably shorter than previously reported. In some birds, brain function had returned within 9 s after the end of stunning.

6. The results suggest that some birds may recover consciousness prior to or during the neck cut. Based on these findings, back-of-the-head stunning and standard head-only stunning of hens should not be recommended without further development.

     

Alteration of fatty acid profile and nucleotide-related substances in post-mortem breast meat of α-lipoic acid-fed broiler chickens

1. The present study was conducted to determine the effects of α-lipoic acid supplementation on post-mortem changes in the fatty acid profile and concentrations of nucleotide-related substances, especially those of a taste-active compound, inosine 5?-monophosphate, in chicken meat.

2. Mixed-sex broiler chicks aged 14 d were divided into three groups of 16 birds each and were fed on diets supplemented with α-lipoic acid at levels of 0, 100 or 200 mg/kg for 4 weeks. Blood and breast muscle samples were taken at 42 d of age under the fed condition and then after fasting for 18 h. The breast muscle obtained from fasted chickens was subsequently refrigerated at 2°C for one and 3 d.

3. α-Lipoic acid supplementation did not affect any plasma metabolite concentration independently of feeding condition, while a slight increase in plasma glucose concentration was shown with both administration levels of α-lipoic acid. In early post-mortem breast muscle under the fed condition, α-lipoic acid had no effect on concentrations of fatty acids or nucleotides of ATP, ADP, and AMP.

4. In post-mortem breast tissues obtained from fasted chickens, total fatty acid concentrations were markedly increased by α-lipoic acid feeding at 200 mg/kg irrespective of length of refrigeration. This effect was dependent on stearic acid, oleic acid, linoleic acid and linolenic acid. However, among fatty acids, the only predominantly increased unsaturated fatty acid was oleic acid.

5. Dietary supplementation with α-lipoic acid at 200 mg/kg increased the inosine 5?-monophosphate concentration in breast meat and, in contrast, reduced the subsequent catabolites, inosine and xanthine, regardless of the length of refrigeration.

6. Therefore, the present study suggests that α-lipoic acid administration altered the fatty acid profile and improved meat quality by increasing taste-active substances in the post-mortem meat obtained from fasted chickens.

     

Early and 24 h post-mortem changes in breast muscle quality traits of two turkey genotypes and their reciprocal crosses raised under semi-confined conditions

1. An experiment was conducted to determine the effect of reciprocal crossing of turkeys on early and 24 h post-mortem changes in quality traits of their breast muscles.

2. The turkeys of slow-growing (SG) and fast-growing (FG) lines as well as SF (SG × FG) and FS crosses (FG × SG) were reared with access to free range.

3. After slaughter turkey breast muscles were examined in the following terms: 5 min, 45 min, 2 h and 24 h post-mortem, for: temperature, pH, glycogen content (G), lactate content (L) and electrical conductivity (EC). Quality attributes of the breast meat were evaluated based on chemical composition, water holding capacity (WHC), cooking loss (%), shear force (N) and colour (L*, a*, b*).

4. Despite differences in the rate of post-mortem changes, the genotype of turkeys had no significant effect upon many quality traits assessed 24 h post-mortem. Meat of lighter birds (SG and SF) was characterised by a lower fat content but a similar protein content compared to meat of FS and FG turkeys. In addition, meat of males from these groups was darker. Meat from the breast muscles of heavier birds (FS and FG) was harder.

5. Significant negative maternal effects were determined for temperature of meat of both male and female turkeys, for pH₂ and EC₂₄ of males as well as for L₂, L₂₄ and cooking loss of female meat. Positive heterosis was confirmed only for pH₂ of female meat and for G₂ of male meat.

6. In summary, the direction of fast- and slow-growing turkey crossing may affect the quality of their meat. However, meat of both types of hybrids reared under semi-confined conditions (with the possibility of using free range) was characterised by appropriate quality parameters.

     

Health status and potential uptake of transgenic DNA by Japanese quail fed diets containing genetically modified plant ingredients over 10 generations

1. The hypothesis assumes that feed containing GMOs affects animal health and results in the transgene product accumulating in the body. Therefore, the objective of the study was to evaluate the impact of genetically modified (GM) ingredients used in poultry diets on aspects of bird health status and accumulation of transgenic DNA in eggs, breast muscle and internal organs.

2. A total of 10 generations of Japanese quail were fed three types of diets: group A – containing GM soya (Roundup Ready) and non-GM maize, group B – containing GM maize (MON810) and non-GM soya, and group C – containing non-GM soya and maize.

3. Bird performance traits were monitored throughout the trial. In 17-week-old animals of each generation, health examination took place on birds from each group including post-mortem necropsy and histological organ evaluation. For the purpose of transgenic DNA detection, samples of selected important tissues were taken. A molecular screening method of PCR amplification was used.

4. The analysis of the sectional examination of birds used in the current experiment did not indicate the existence of the pathological changes caused by pathogens, nutritional factors or of environmental nature. The histopathological changes occurred in all three dietary groups and there were no statistically significant differences between the groups.

5. There was no transgene amplification – neither CaMV35S promoter sequence nor nos terminator sequence, in the samples derived from breast muscle, selected tissues and germinal discs (eggs).

6. According to the obtained results, it was concluded that there was no negative effect of the use of GM soya or maize with regard to bird health status or to the presence of transgenic DNA in the final consumable product.

     

Effects of light on responses to low atmospheric pressure stunning in broilers

1. Low atmospheric pressure stunning (LAPS) is a novel approach to poultry stunning involving the application of gradual decompression lasting 280 s according to a prescribed pressure curve.

2. The aim of this study was to determine how behavioural, electroencephalogram (EEG) and electrocardiogram (ECG) responses to LAPS are influenced by illumination of the decompression chamber. A secondary aim was to examine responses to the decompression chamber without LAPS being applied, as such a “sham” control has been absent in previous studies.

3. A two by two factorial design was employed, with LAPS/light, LAPS/dark, sham/light and sham/dark treatments (N = 20 per treatment). Broilers were exposed to each treatment in pairs, in each of which one bird was instrumented for recording EEG and ECG. Illumination was applied at 500 lx, and in sham treatments, birds were identically handled but remained undisturbed in the LAPS chamber without decompression for 280 s.

4. Birds which underwent the sham treatment exhibited behaviours which were also observed in LAPS (e.g. sitting) while those exposed to LAPS exhibited hypoxia-related behaviours (e.g. ataxia, loss of posture). Behavioural latencies and durations were increased in the sham treatments, since the whole cycle time was available (in LAPS; birds were motionless by 186 s).

5. Within the sham treatments, illumination increased active behaviour and darkness induced sleep, but slow-wave EEG was seen in both. The pattern of EEG response to LAPS (steep reduction in median frequency in the first 60 s and increased total power) was similar, irrespective of illumination, though birds in darkness had shorter latencies to loss of consciousness and isoelectric EEG. Cardiac responses to LAPS (pronounced bradycardia) closely matched those reported previously and were not affected by illumination.

6. The effects of LAPS/sham treatment primarily reflected the presence/absence of hypoxia, while illumination affected activity/sleep levels in sham-treated birds and slowed time to unconsciousness in birds undergoing LAPS. Therefore, it is recommended that LAPS be conducted in darkness for poultry.

     

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.

     

Effects of acetylated wood powder on growth performance,hepatic and muscular free amino acid profiles,and inosine 5’-monophosphate concentration of breast meat in broiler chickens

1. The present study was conducted to determine the effects of acetylated wood powder (AW) as a new feed additive on performance, liver and muscle metabolism of amino acids and fatty acids and nucleotide-related substances of meat in broiler chickens. It was hypothesised that acetic acid desorbed from AW during intestinal digestion affects tissue metabolism.

2. Two-week-old broiler chicks were divided into four groups and fed on diets supplemented with wood powder (30 g/kg) less than 106 µm in diameter, except for controls. The AW was added to diets at 0, 10 and 30 g/kg to replace the non-acetylated wood powder (NAW) for 26 d. Plasma, liver tissue and breast muscle were taken from half of birds at 40 d of age under the fed condition. After the remaining chickens were fasted for 14 h, breast muscle was taken and refrigerated for 24 h.

3. Consumption of wood powder with or without acetyl groups had no effect on growth performance including tissue weights of abdominal fat and breast muscle and plasma metabolites.

4. Feeding AW decreased total free amino acid concentrations in the liver compared to the group only fed on the NAW. This response was dependent mainly on reduced non-essential and glucogenic amino acid concentrations. However, in breast muscle, alterations of free amino acid concentrations were observed only for histidine and tryptophan. In addition, the fatty acid composition of liver and breast muscle was not affected by feeding AW.

5. In breast meat obtained from fasted chickens, the higher level of AW increased the concentration of inosine 5′-monophosphate, a taste-active compound, and in contrast, decreased the subsequent catabolites (inosine and hypoxanthine). However, the concentration of glutamic acid, a taste-active compound, was lowered at this level of AW ingestion.

6. Therefore, this study suggested that feeding AW as a new feed additive regulates ante-mortem amino acid utilisation in the liver and contributes to retard post-mortem degradation of inosine 5′-monophosphate as a taste-active compound in chicken meat.

     

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.

     

Influence of indoor microbial aerosol on the welfare of meat ducks

1. The aim of the study was to evaluate the effects of microbial aerosols on ducks’ welfare and provide information on which to establish microbial aerosol concentration standards for poultry.

2. A total of 1800 1-d-old Cherry Valley ducks were randomly divided into 5 groups (A, B, C, D and E) with 360 ducks in each. To obtain objective data, each group had three replications. Different microbial aerosol concentrations in different groups were created by controlling ventilation and bedding cleaning frequency. Group A was the control group and hygienic conditions deteriorated progressively from group B to E.

3. A 6-stage Andersen impactor was used to detect the aerosol concentration of aerobes, fungi, gram-negative bacteria and an AGI-30 microbial air sampler detected endotoxins. Physiological stress was evaluated in the ducks by adrenocorticotropic hormone (ACTH) values in serum.

4. To assess the effects of bioaerosol factors, welfare indicators including fluctuating asymmetry (FA), appearance and gait as well as the Lactobacillus caecal concentration were evaluated.

5. The data showed group D had already reached the highest limit of concentration of airborne aerobic bacteria, airborne fungi, airborne gram-negative bacteria and airborne endotoxin. The ducks in this group had significantly increased serum ACTH values and significantly decreased caecal lactobacilli concentration. Furthermore, appearance and gait scores, wing length and overall FA and caecal Lactobacillus concentration in this group were significantly increased at 6 and 8 weeks of age.

6. In conclusion, high concentrations of microbial aerosol adversely affected the welfare of meat ducks. The microbial aerosol values in group D suggest a preliminary upper limit concentration of bioaerosols in ambient air for healthy meat ducks.

     

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.

     

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.

     

Lactic acid bacteria isolated from poultry protect the intestinal epithelial cells of chickens from in vitro wheat germ agglutinin-induced cytotoxicity

1. Poultry fed on wheat-based diets regularly ingest wheat germ agglutinin (WGA) that has toxic effects in vitro on intestinal epithelial cells (IEC) obtained from 14-d-old broilers. Cytotoxicity and the potential role of 14 intestinal bacterial strains in the removal of bound lectins in epithelial cell cultures were investigated.

2. Cytotoxicity was dependent on time and lectin concentration; the lethal dose (LD₅₀) was 8.36 µg/ml for IEC exposed for 2 h to WGA.

3. Complementary sugars to WGA were detected on the surface of one Enterococcus and 9 Lactobacillus strains isolated from poultry. These strains were evaluated as a lectin removal tool for cytotoxicity prevention.

4. Incubation of lactic acid bacteria with WGA before IEC–lectin interaction caused a substantial reduction in the percentage of cell deaths. The protection was attributed to the amount of lectin bound to the bacterial surfaces and was strain-dependent. L. salivarius LET 201 and L. reuteri LET 210 were more efficient than the other lactic acid bacteria assayed.

5. These results provide a basis for the development of probiotic supplements or cell-wall preparations of selected lactic acid bacteria intended to avoid harmful effects of a natural constituent of the grain in wheat-based diets.

     

Genetic variation for worm burdens in laying hens naturally infected with gastro-intestinal nematodes

1. Genetic parameters were determined for the worm burden of the most common gastro-intestinal nematodes in two chicken genotypes after being exposed to free-range farming conditions for a laying period.

2. Seventeen-week-old hens of 2 brown genotypes, Lohmann Brown (LB) plus (n = 230) and LB classic (n = 230), were reared for a laying period and subjected to post-mortem parasitological examinations at 79 weeks (LB plus) or 88 weeks (LB classic) of age.

3. There was no significant difference in faecal egg counts between the genotypes. Almost all hens (>99%) were infected with at least one nematode species. Species-specific nematode prevalence ranged from 85.8% to 99.1% between the two genotypes. Heterakis gallinarum was the most prevalent nematode (98.5%), followed by Ascaridia galli (96.2%) and Capillaria spp. (86.1%). Capillaria spp. were composed of C. obsignata (79%), C. caudinflata (16%) and C. bursata (5%).

4. All phenotypic and genetic correlations among worm counts of different parasite species were positive in combined genotypes (r_P ranged from 0.05 to 0.30 and r_G ranged from 0.29 to 0.88). A strong genetic correlation (r_G = 0.88 ± 0.34) between counts of A. galli and H. gallinarum was quantified. Heritability for total worm burden for LB plus and LB classic, respectively, were 0.55 ± 0.18 and 0.55 ± 0.34. Across both genotypes, the heritability of total worm burden was 0.56 ± 0.16.

5. In conclusion, there is a high variation attributable to genetic background of chickens in their responses to naturally acquired nematode infections. The high positive genetic correlation between counts of closely related worm species (e.g. A. galli and H. gallinarum) may indicate existence of similar genetically determined mechanism(s) in chickens for controlling these nematodes.

     

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.

     

Effects of ionised or chelated water-soluble mineral mixture supplementation on growth performance,nutrient digestibility,blood characteristics,meat quality and intestinal microbiota in broilers

1. An experiment was conducted to study the effects of dietary supplementation of water-soluble ionised or chelated mineral mixture on growth performance, nutrient digestibility, blood characteristics, relative organ weight, meat quality and excreta microflora in broilers.

2. A total of 408 Arbor Acres broilers (17 birds in 8 replicate pens) were randomly allocated into one of the following three treatments: (1) Control/basal diet (CON), (2) T1 (basal diet + 0.5% ionised mineral mixture solution, pH 3.0) and (3) T2 (basal diet + 0.5% chelated mineral mixture solution, pH 3.0).

3. The body weight gain was greater and feed conversion ratio was lower in broilers supplemented with ionised or chelated mineral liquid complex compared to CON during the grower and overall phase of the experiment.

4. No significant effect in the concentration of Ca and P in the blood was observed in birds supplemented with ionised or chelated mineral mixture solution. No adverse effects were observed in organ weight and meat quality with ionised or chelated mineral mixture supplementation.

5. Regarding intestinal microbiota counts there was a reduction of Escherichia coli counts in the small intestine in ionised mineral supplemented birds. In the large intestine, E. coli as well as Salmonella populations were reduced in ionised mineral supplemented birds.

6. In conclusion, ionised or chelated minerals have partial positive effects in improving growth performance and reducing pathogenic bacteria load in the gastro-intestinal tract.

     

Hepatic expression of FTO and fatty acid metabolic genes changes in response to lipopolysaccharide with alterations in m6A modification of relevant mRNAs in the chicken

1. The fat mass and obesity associated (FTO) gene, which encodes a demethylase of m⁶A, has been reported to respond to lipopolysaccharide (LPS) and to serve as a link between inflammation and metabolic responses. The objective of this study was to determine whether LPS-induced changes in the expression of FTO and metabolic genes are associated with alterations of m⁶A in relevant mRNAs.

2. LPS challenge significantly decreased hepatic mRNA expression of carnitine palmitoyl transferase 1 (CPT1) and CPT2, which coincided with a tendency of higher triglyceride accumulation in the liver.

3. LPS significantly down-regulated the full length cFTO1, yet up-regulated the truncated cFTO4 protein in the liver nuclear extracts.

4. Nuclear protein content of cFTO4 in the liver was negatively correlated with the mRNA abundances of CPT1 (r = 0.629) and CPT2 (r = 0.622).

5. Methylated RNA immunoprecipitation analysis revealed that the m⁶A level around the translation start site of CPT1 was markably decreased in the liver of LPS-treated chickens.

6. These results indicate that LPS-induced changes in FTO protein expression are associated with alteration of mRNA m⁶A modification in chicken liver.