British Poultry Science最新文献

1. The demand for natural alternatives to antibiotic growth promoters in poultry has led to growing interest in bioactive compounds, such as polysaccharides derived from algae. This study evaluated the effects of algae (Spirulina platensis)-derived polysaccharides (ADP) on growth performance, blood profiles, carcase characteristics, meat quality, amino acid composition and antioxidant status in broilers.2. A total of 320, 1-d-old Ross 308 mixed-sex broilers were randomly allocated to one of the five dietary treatments; a control diet (0% ADP) and diets supplemented with 0.15%, 0.30%, 0.45% and 0.60% of ADP. Each treatment included four replicates containing 16 birds each. The feeding trial was conducted over 42 d and was divided into three phases, including starter (1-14 d), grower (15-28 d) and finisher (29-42 d).3. Dietary inclusion of ADP at 0.30% significantly improved body weight gain and feed conversion ratio during the finisher (1.77 kg and 1.71, respectively) and overall (2.82 kg and 1.56, respectively) periods. There were no adverse effects observed on haematological, serum biochemistry or carcase characteristics.4. Supplementation with 0.45-0.60% ADP reduced cooking loss to 34-40% and improved meat cohesiveness by about 5%. Its inclusion elevated the levels of key amino acids, such as threonine, histidine, isoleucine, arginine and glutamic acid in the breast muscle. Additionally, ADP linearly increased hepatic antioxidant enzyme activities, including total superoxide dismutase (317.60-337.12 U/mg protein), glutathione peroxidase (39.98-48.70 U/mg protein), catalase (7.09-7.71 U/mg protein) and decreased malondialdehyde concentrations (0.63-0.68 nmol/mg protein) demonstrating enhanced oxidative status. These improvements were attributed to the prebiotic and antioxidant properties of Spirulina-derived polysaccharides, which enhance nutrient utilisation, maintain gut integrity and strengthen redox balance.5. This study provides preliminary evidence that polysaccharides derived from S. platensis, particularly at 0.30-0.45%, can be used as safe and effective feed additives in broiler diets. These compounds have the potential to enhance performance, oxidative stability and certain aspects of meat quality without adverse effects.

1. Wooden breast (WB) is a common muscle abnormality in the pectoralis major (PM) muscle of broilers that results in significant economic losses for the poultry industry, although its incidence varies in different broiler lines. However, there are few reports on the genes and pathways involved in WB using RNA-seq or microarray data across multiple lines.2. The current study obtained three datasets (GSE127806, GSE144000 and GSE79276) from different broiler lines in the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was then performed using GSE127806 and GSE144000 datasets and identified consensus modules significantly correlated with WB (p ≤ 0.05). Preservation analysis showed that one consensus module was strongly preserved (Zsummary < 2), and two others were moderately preserved (2 < Zsummary < 10) in the GSE79276 dataset.3. Functional enrichment analysis revealed seven key genes (FN1, SPP1, CD44, TNC, BAK1, TNFRSF1A and CTSK) related to WB were significantly enriched in the extracellular matrix (ECM)-receptor interaction pathway and in the apoptosis pathway in one consensus module. The genes ACO2, MDH2 and SUCLG1 were significantly enriched in the tricarboxylic acid cycle (TCA) cycle pathway. From the protein-protein interaction analysis, hub genes linked to WB were identified. Seven of these genes are known to participate in muscle contraction (TNNI1, TNNT1, TNNT2, TNNT3, TPM3, TMOD3 and TMOD4) and three others in the TCA cycle (ACO2, MDH2 and SUCLG1).4. This study identified key genes and pathways associated with WB, deepening the understanding of the mechanism by which fibrosis (mediated by genes such as FN1) influences WB. It further revealed the important role of the TCA cycle and apoptosis in the pathogenesis of WB.

1. This study examined the rhythmatic immune response of chickens in the early stages of Campylabacter jejuni infection over time. Chickens were inoculated with C. jejuni at 10:00, 14:00 and 18:00 h, respectively.2. The C. jejuni populations in the caecal and the levels of IL-8, IL-18, IL-1β, IgA, IgY and cytokine signal transduction inhibitor 3 protein (SOCS3) in serum for each individual were measured at different hours after inoculation (hpi). Cosine and regression analyses were assessed for rhythmicity and correlations.3. The log₁₀CFU of C. jejuni number in the caecal content was the lowest (7.4-8.1) at 10:00 h and highest (9.4-9.8) at 18:00 h. Inoculation status and time points post-inoculation had significant effects on IL-8, IL-18, IL-1β, IgA, IgY and SOCS3 levels (p < 0.001). The IL-8, IL-18, IL-1β and IgY levels at 16 hpi were the lowest compared to other post-inoculated time points.4. The IL-8, IL-1β, IgA and SOCS3 levels of the control and treated groups showed rhythmic changes at 18:00 (p < 0.05). Caecal C. jejuni colonisation was significantly correlated with levels of IL-18, IL-1β, IgA, IgY and SOCS3 (r = 0.35-0.76; p < 0.05), among which IgY had the highest correlation coefficient (r = 0.76; p < 0.0001).5. Chickens were more sensitive to C. jejuni inoculation administered at 18:00 h. Moreover, the changes of IgA, IL-8 and IL-1β levels were lowest at 16 hpi and more likely to show circadian rhythms in chickens inoculated at 18:00 h.

1. Using whole-genome comparative analysis, this study elucidated the genetic differentiation characteristics and domestication selection mechanisms between Bashang long-tail chickens and their wild ancestor, the red junglefowl.2. Linkage disequilibrium (LD) analysis investigated genome-wide recombination patterns, while population genetic structure analysis was conducted to assess the degree of differentiation between the two populations. Additionally, a multi-method selective sweep analysis was performed to identify genomic regions under selection.3. The LD decay rate in Bashang long-tail chickens was significantly slower than in red junglefowl, which indicated reduced genome recombination due to long-term artificial selection. Population structure analyses, including neighbour-joining trees, principal component analysis and admixture assessments consistently revealed significant genetic differentiation between the two groups.4. By integrating fixation index, Tajima's D and nucleotide diversity ratio metrics, 102 high-confidence selective sweep regions were identified, encompassing 22 key candidate genes, including three genes (ALX1, RASSF9 and NTS) with potentially adaptive missense mutations, which exhibited strong selection signals. Functional enrichment analysis indicated that these genes were enriched in key biological pathways, including carbohydrate/protein metabolism and neural regulation.5. This data provided genomic signatures of domestication-driven adaptation variations accumulated during the domestication of Bashang long-tail chickens, offering new perspectives on the genetic mechanisms underlying chicken domestication. The study provided potential molecular markers for conserving local chicken genetic resources and molecular breeding.

1. Three experiments were conducted to evaluate the predictive value of pepsin digestibility for estimating apparent metabolisable energy corrected for nitrogen balance (AMEn) and true ileal digestibility coefficients of amino acids (TIDCAA) in animal-origin meals (AOM) for broilers.2. Two poultry offal and bone meals (POBM1 and POBM2) and one swine offal and bone meal (SOBM) were assessed using in vivo and in vitro methods.3. In vivo trials determined AMEn and TIDCAA using a completely randomised design with 16 treatments, 8 replicates and 10 birds per replicate, while pepsin digestibility was measured in vitro.4. Pepsin digestibility showed variable correlations with nutrient values. In POBM1, only arginine showed a significant negative correlation with AMEn and TIDCAA. For POBM2, significant positive correlations with TIDCAA were observed only for lysine, histidine and glycine and for SOBM, a quadratic pattern was observed for TIDCAA, with no significant effect on AMEn.5. The results indicated that pepsin digestibility may be a useful predictor of amino acid digestibility in AOM, but its reliability for estimating AMEn was limited and dependent on ingredient type.

1. This study was conducted to evaluate the effect of dietary crude protein level and protease supplementation on production performance and blood biochemical traits of aged laying hens.2. Forty Lohmann Brown hens at 68 weeks of age were fed two diets differing in crude protein levels (CP, 120 g/kg or 160 g/kg), supplemented or not with protease at 50.0 mg/kg feed. Each treatment included ten replicate cages with one hen per replicate. The study lasted for a duration of 32 weeks. Egg production performance was measured every 4 weeks and blood chemistry and electrolyte variables were assessed at the end of the study.3. Results showed that there was no interaction (p > 0.05) between dietary crude protein level and protease supplementation on any production or blood measurements. Hens fed 120 g/kg CP diet had lower (p < 0.05) production rate, egg mass, feed intake, body weight and less favourable feed conversion ratio (FCR) compared to those fed 160 g/kg CP diet. Supplementation with protease, independent of dietary crude protein level, increased egg production (+4.8 points; p < 0.05) and mass (+3.3 g; p < 0.05), blood creatine kinase (+103%; p < 0.05) and decreased FCR (-0.51points; p < 0.05) and blood phosphorus (-18%; p < 0.05).4. The results demonstrated that protease supplementation enhanced egg production performance in aged laying hens, regardless of whether they were fed CP-adequate or deficient diets. This improvement could be partially associated with accelerating energy metabolism, as evidenced by elevated blood creatine kinase levels. These findings highlighted the potential of protease to reduce dietary protein inclusion while extending laying hens' productive lifespan and enabling the development of blood biochemical signatures for exogenous protease applications.

1. This study investigated whether the recessive ce gene, which causes the celadon shell colour in Japanese quail eggs and affects the shell structure and quality of both fresh eggs and eggs stored for 28 days at 4°C.2. Analyses were conducted on 54 fresh and 54 stored eggs from four quail groups, including those with typically wild-type shell pigmentation: Jumbo, Pharaoh and Texas, as well as Celadon laying eggs with reduced protoporphyrin (ce). Results included shell weight, ratio of shell to egg weight, shell strength with simultaneous acoustic measurement and shell microstructure using computed microtomography (both 2D and 3D). The quality of fresh and stored eggs was evaluated based on egg weight, yolk weight and proportion (%), yolk index, albumen quality, vitelline membrane strength and elasticity, pH and water activity of yolk and albumen and yolk viscosity. Egg weight (water) loss was measured in stored eggs.3. Celadon eggs had a higher number of shell pores, but the average pore area and its area-equivalent circle diameter were smaller. No differences in eggshell strength were found between Celadon and wild-type pigmented eggs, which was confirmed by acoustogram analysis. Celadon shells displayed a negative Euler number, which indicated strong connections between adjacent pores. This structural enhancement may be an adaptation to compensate for reduced protoporphyrin content.4. Celadon quail eggs were similar in quality to those of the other groups and could be stored with similar results. The greatest weight loss during storage was observed in Texas quail eggs, which exhibited the highest porosity (based on the number and surface area of pores) and the greater morphometric water vapour conductance.

1. This study characterised the H5N8 highly pathogenic avian influenza (HPAI) viruses, clade 2.3.4.4b from backyard waterfowl selected from Menoufia governorate during 2022. Genetic and antigenic analysis of H5N8 isolates was performed and the genetic markers for waterfowl brain invasion were analysed by whole genome sequencing.2. Molecular diagnosis of field samples showed that, out of 30 tested waterfowl flocks showing respiratory and nervous symptoms of the disease, 13 duck flocks and 11 geese flocks were confirmed positive for H5N8 by RT-qPCR.3. The whole genome sequencing for four H5N8 strains were performed from duck and geese flocks. Phylogenetic analysis of the hemagglutinin (HA) gene revealed that the 2022 isolates clustered with Russian and European-like strains. All strains had a polybasic cleavage site (PLREKRRKRGLF), indicating high pathogenicity. Mutations, such as A140T, G268E, R82K, and I162M, were identified and linked to antigenic drift and adaptation.4. Brain-derived isolates showed specific HA mutations (e.g. F244L, I248S, K234R) compared to tracheal isolates, which suggested possible roles in neurotropism. Internal genes revealed mammalian adaptation markers such as 504 V (PB2), 127 V and 672 L (PA), and 133 G (PB1), with additional unique mutations observed H5N8 strains isolated from geese in 2022. Reassortment analysis for the 8 gene segments showed that H5N8 duck strains isolated in 2018 belonged to genotype G1, while the 2022 strains belonged to genotype G4. This confirmed changes after 2018 and reflecting continuous viral evolution through segment reassortment.5. Antigenic analysis revealed that the newly introduced H5N1 virus clade 2.3.4.4b is antigenically similar with H5N8 viruses from the same clade, while different from viruses in other clades.

1.This study investigated antimicrobial resistance and virulence factors in Salmonella enterica subsp. enterica serovar Thompson (SET) isolates from broilers in the Brazilian poultry industry.2. Among 44 isolates, 18.18% showed phenotypic resistance, with tetA, sul1 and sul2 genes frequently detected, while sul3 was absent. Two isolates carried clinically relevant resistance genes: blaCTX-M-1 (ESBL) and OXA-48 (carbapenemase).3. The PFGE analysis revealed five distinct clusters with low genetic diversity, which suggested a clonal dissemination pattern. One strain from cluster E showed the highest pathogenicity in broilers, underscoring the need for continued molecular surveillance in poultry production.

1. This study examined the effects of providing feed and water immediately post hatch in combination with inclusion of Neurospora intermedia biomass in chick starter diet, as a source of protein and bioactive compounds. Variables monitored were caecal microbiota, total levels of IgY, specific antibody responses to vaccination and blood leukocyte counts.2. Ross 308 chicks were subjected to two hatching treatments - immediate access to feed and water, or delayed access at 48 h. In addition, three starter diets were fed until d 10: a control diet (C), a diet with inclusion of 10% N. intermedia (N) or diet N followed by diet C (NC).3. Chicks were vaccinated against avian pneumovirus (APV) and focal birds were repeatedly blood sampled for quantification of total IgY and antibodies specific to APV in serum. Birds fed starter diet C were sampled for measures of blood leukocyte counts. Caecal microbiota were studied in birds sacrificed on d 5, 9 and 43, respectively.4. With age, microbial richness in caeca increased and there was a shift in composition, but no effects of hatching treatment or starter diet were observed.5. Neither the starter diet nor the hatching treatment affected the total IgY in serum or specific antibody responses to APV vaccination. Late-fed chicks had a significant decrease in the total amount of IgY in serum from d 2 to d 8, likely a consequence of dehydration at d 2. Early feeding did not affect any of the leukocyte populations monitored.6. In conclusion, there were no effects of early feeding or inclusion of N. intermedia on gut microbiome or the immune traits monitored. However, the absence of adverse effects of a starter diet with the fungal biomass suggested that N. intermedia is a source of high-quality protein.