British Poultry Science最新文献

1. This study assessed the impact of feeding a high nutrient specification (HS) diet, recommended for fast growing broilers and a low nutrient specification (LS) diet, recommended for slow growing broilers, on growth performance variables, including feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) and production characteristics of fast growing Ross 308 broilers and slow growing Redbro broilers.2. As hatched, Ross 308 (n = 210) and Redbro broilers (n = 210) were randomly allocated to 28 floor pens, 14 pens for each genotype and fed experimental diets from 0 to 42 d of age over four feeding phases. Each diet was fed to seven pens of each genotype, following a randomised, blocked, factorial design.3. Growth performance variables were determined for each feeding phase. Excreta were collected during the last 4 d of the study to determine dietary N-corrected apparent metabolisable energy (AMEn) and nutrient retention coefficients. At 42 d of age, one bird per pen was humanely killed and samples were obtained for determination of meat quality variables, jejunal histomorphology and liver triglycerides.4. Feeding the HS diet increased FI (p < 0.05), WG (p < 0.001) and reduced FCR (p < 0.001) in both genotypes from 0 to 42 d compared to feeding the LS diet. Feeding the HS diet increased AMEn intake (p < 0.001). Diet did not affect breast meat quality, except for increasing drip loss in Ross 308 broilers (p < 0.05), nor did it affect breast myopathies, jejunal morphology, or liver function. Therefore, feeding the HS diet, which was formulated to meet the nutrient recommendations for Ross 308, can be a practical strategy to improve the feed efficiency of Redbro broilers.

1. Highly pathogenic avian influenza (HPAI) A(H7N3) viruses have continued to circulate in Mexican poultry since their initial identification in the summer of 2012. Although several control strategies have been implemented, the virus has spread to several states, causing enormous economic losses in the commercial poultry sector. Important factors to ensure vaccine potency include a close match between the antigen and circulating strains and using sufficient antigen to protect the birds and prevent shedding during subsequent infections.2. The following study investigated the haemagglutin (HA) concentration of an adjuvanted vaccine produced from a reverse genetics-modified low-pathogenic avian influenza A(H7N3) virus that could protect chickens against homologous challenge. Inactivated vaccine formulations with different HA concentrations (0.8, 1.1, 1.3 and 3.1 μg/0.5 ml haemagglutinin) were prepared and tested in chickens.3. The results showed that the formulations containing 1.1 μg or more of HA per 0.5 ml dose protected the birds against disease symptoms and reduced viral replication when compared with the vaccine containing 0.8 μg/0.5 ml.

1. Duck Tembusu virus (DTMUV) envelope (E) protein, a surface-exposed structural component, plays a key role in viral entry and induction of neutralising antibodies. However, the antigenic potential of its domains and their immunogenicity remains largely unexplored.2. In this study, in silico analyses were conducted to predict antigenic epitopes and guide construct design. Full-length E protein and domains were expressed in E. coli and baculovirus. These were used to immunise ducks. Antigenicity was evaluated as IgG titres and cytokine profiling.3. Domain III (DIII) of the E protein was the major contributor to antigenicity and is a promising subunit vaccine candidate against DTMUV.

1. This study evaluated body weight and egg production performance of Tilili indigenous chicken from different filial generations as a result of the selective breeding.2. The base populations (G-0) were established from 3,400 one-day-old chicks, which were hatched from 12 500 eggs collected from remote villages in Sekela and Tilili districts in 2021. During the selection program, body weight was recorded at hatch and every two weeks, while egg production data were recorded from the onset of lay to 44 weeks.3. Higher 16th-week body weight and higher cumulative 24-week egg production were selection criteria of the breeding program. Accordingly, 400 hens and 40 cocks were selected based on week sixteen body weight as selection candidates for the next generations, and 200 hens were selected based on their cumulative egg production in 24 weeks after start of lay to produce the next generation.4. Body weight traits significantly (p < 0.001) increased from Generation 0 (G0) to Generation 3 (G3). At 16 weeks of age, average body weights for G0, G2, and G3 were 814.6 g, 1100.6 g, and 1369.1 g, respectively, an overall gain of 68.1% from G0. Likewise, there was a significant (p < 0.001) increment (111.5%) in 24-week egg production in the progressive generations; 39.7, 48.03, and 82.5 eggs for G0, G2, and G3, respectively. A positive association of body weight with 24-week egg number suggested both traits improved simultaneously. Mortality rate declined significantly (p < 0.001) across generations.5. Overall, the Tilili chicken breeding program had improvements in growth, egg production, and survivability. However, genetic and phenotypic evaluations are needed due to potential negative genetic correlations between traits. Furthermore, it is essential to validate the phenotypic improvements by conducting a signature selection study using whole-genome analysis to identify the genome regions influenced by the selective breeding program.

1. Listeria monocytogenes (L. monocytogenes) is a Gram-positive bacterium and a significant foodborne pathogen that causes listeriosis and occurs in animal products and other foods. Information on the prevalence of L. monocytogenes in poultry carcasses at abattoirs across Taiwan is limited.2. This study investigated L. monocytogenes contamination in poultry carcasses at abattoirs across Taiwan from 2014 to 2024, covering chickens (2014-2024), ducks (2019-2024) and geese (2020-2024) slaughter lines.3. In 2014, 20% of post-chill chickens tested positive for L. monocytogenes (95% CI: 15.1-25.6). Following government intervention and mandatory monitoring across 2014-2024, the prevalence declined steadily and was 0% in 2022-2024. Among all chicken isolates, 73 samples (56.6%) were identified as serogroup 1/2a, 3a; 26 (20.2%) as serogroup 1/2b, 3b; 2 (1.6%) as serogroup 1/2c, 3c; 2 (1.6%) as serogroup 4b, 4d, 4e; and 26 isolates were non-typable. Among all poultry species examined, ducks showed L. monocytogenes in 0.7% (95% CI: 0.0-3.9) of samples in 2019 and 0.5% (95% CI: 0.0-2.7) in 2020; both isolates belonged to serogroup 1/2a, 3a.4. Among all poultry species examined, geese had detection rates of 0.9% (95% CI: 0.0-4.7) in 2020 and 0.8% (95% CI: 0.0-4.6) in 2021. One sample was identified as serogroup 1/2a, 3a, while the other was classified as serogroup 4b, 4d, or 4e.5. Since L. monocytogenes is commonly linked to animal-derived and ready-to-eat foods, nationwide surveillance at abattoirs, together with official controls and industry improvements, is crucial for ensuring food safety.

1. This study measured the changes in weight, size, ash, calcium and phosphorus in the skeletons of growing broilers. Ross 308 broilers were sampled at intervals from hatch to 85 d of age. The selected birds were weighed individually, killed by cervical dislocation and defeathered.2. The skeleton of each bird was excised and defleshed and divided into its component bones which were weighed before and after drying and defatting. The length and width of the metatarsus, ulna, humerus, tibia and femur were measured. The ash content of each component of the skeleton was determined. Ca and P contents were measured in the humerus, tibia and pelvis ash of three birds of each sex.3. Gompertz parameters were determined for the feather-free body and for each of the components. Rates of maturing were maintained for all components within a sex, as these are allometrically related. The slope of the plots of the natural logarithms of skeleton ash and feather-free body weight suggested that the ratio between these increased with age and were predicted using allometry.4. Tibial Ca and P formed a constant proportion of ash in the tibia but these proportions were lower in the humerus and pelvis. Hence, caution must be applied when extrapolating tibia values to the contents of the entire skeleton. The proportion of ash found in the skeleton components changed as the broiler grew, which was in a manner that was predictable using allometry with body protein. Fluctuations in the ratio between ash and body protein over the growth period suggested that birds may not be reaching their potential skeleton mineralisation with the feeds provided.

1. Transporting animals under inappropriate conditions causes pain and suffering to the animals and causes financial loss for the producers. This study investigated the effects of the season and transportation distance on the dead-on-arrival (DOA), reject rate (due to lesions and damage) and body weight loss parameters of the broiler breeder (BB) chickens during transportation from the farm to the slaughterhouse.2. Data was obtained by analysing two-year records of a commercial slaughterhouse in Turkey. During the period examined, 2,452,624 BB were transported and slaughtered to this slaughterhouse by 554 trucks.3. The lowest DOA rate (0.186%) occurred in the summer season and the reject rate in summer (0.104%) was lower than in other seasons. During the monitored period, the effect of season on body weight loss was not statistically significant. When the impact of transportation distance was considered, there was more body weight loss (1.663%) in animals transported over longer distances.4. The data highlighted how important it is to pay attention to transportation conditions of these animals to the slaughterhouse, especially under cold climate conditions and over long distances, both in terms of animal welfare and economics.

1. The current study investigated the effects of different egg incubation temperatures and sex on local and systemic immune parameters post-hatch in Ross 308 broilers. It was hypothesised that increased or decreased incubation temperature could support the developing immune system.2. In total, 405 eggs from a 49-week-old breeder hens were divided into three groups and incubated between embryonic days (ED) 4-7, at different temperatures: normal/control (37.5°C), lower (36.5°C) or higher (38.5°C). After hatching, the broilers were sexed and reared for 35 d. Blood samples and tissue samples from the spleen and ceacal tonsils were analysed for various immune parameters from a sub-set of the chickens representing all treatments.3. The results showed that the 38.5°C treatment provided significant immunomodulation by altering the number, percent and expression of surface receptors in various leukocyte subsets. However, interpreting the observed differences in terms of immunocompetence was ambiguous. The 36.5°C treatment showed a potential improvement in immune function by increasing the opsonisation potential of blood serum indicating a potential beneficial effect of the lowered temperature.4. Regarding immunological differences between sexes, females had a higher percentage of MHC-II positive monocytes/macrophages and a higher cell surface expression of MHC-II in the caecal tonsils than males.

1. Copy number variation (CNV) is an important source for identifying genetic differences. This study compared the genome-wide CNV and their regions (CNVR) across 16 Chinese local duck breeds and detected key genes and pathways involved in growth and reproduction-related traits using this dataset.2. Breakdancer, Pindel and CNVnator were used to detect reliable CNV, and HandyCNV was used to obtain CNVR. Selection signatures were analysed in meat (MD) and egg-laying ducks (ED) compared to wild ducks (WD) using fixation and differentiation index DIsv methods. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was carried out to identify key pathways and related genes.3. Principal component analysis (PCA) using CNV data clustered 127 ducks into 4 populations: WD, MD, ED and meat+egg-type ducks (MED). In total, 237,630 CNV and 6,176 CNVR were detected across these samples. Intersection analysis identified 1,384 common CNVR and 2,105 unique CNVR. The KEGG analysis showed that common CNVR were enriched in 7 basic life activity pathways, while unique CNVR were enriched in 9 population-specific pathways. Compared to WD, MD selection signatures were found in 4 enriched pathways and 8 genes (LRP2, NID1, ATP1B3, PDGFD, MAGI2, FLT1, DMD, RALGAPB) related to growth and meat traits. The ED signatures revealed three key pathways and eight genes (PRKN, CTNNA2, DLG2, PDGFD, PRKD1, RAPGEF4, EIF2S1, CRB2) linked to reproduction.4. Using this dataset comprising 16 duck breeds, CNVR patterns were compared among WD, MD, ED and MED birds to identify common and unique CNVR. The study investigated selection signatures in MD and ED ducks and revealed key pathways and candidate genes related to growth and reproduction.

1. The present experiment assessed the influence of feed particle size (FPS) and live-attenuated coccidiosis vaccination (COV) at one day of age on the performance, serum biochemistry, gastrointestinal tract (GIT) development and meat quality of broiler chickens.2. The experiment employed a 2 × 2 factorial design of treatments, with two types of FPS (fine and coarse) and two COV programs (with and without vaccine) with six replicate pens per treatment each containing 20 broilers.3. Cereals were passed through 4 mm and 8 mm sieves to create feed mixtures with finely ground (FGF) and coarsely ground (CGF) particle sizes, respectively. Broiler maize, wheat and soybean diets were provided ad libitum from d 1 to 13, 14 to 26 and 27 to 39 of age, respectively.4. At d 13, 26 and 39, birds fed on CGF had higher body weight and weight gain (p < 0.01) compared to those receiving FGF. During the starter period, vaccination increased FI in chicks fed FGF; however, this effect was not observed in birds fed CGF (FPS × COV interaction; p < 0.01). At all control points, significant FPS x COV interactions (p < 0.05) were noted for feed conversion ratio (FCR) with COV negatively impacting FCR only in the FGF-fed broilers.5. Serum biochemistry and GIT characteristics tended to be affected by COV. However, birds fed on CGF had relatively shorter and lighter small intestines compared to those consuming FGF (p < 0.01). The water holding capacity in breast meat decreased in relation to COV (p < 0.01).6. The results indicated that coarse grinding of feed was more effective in accommodating COV-induced growth retardation in broilers when compared to fine grinding.