British Poultry Science最新文献

1. Clustered regularly interspaced short palindromic repeats (CRISPR)-associated proteins (Cas) systems have been highlighted for their potential applications in controlling the spread of mobile genetic elements, including antimicrobial resistance (AMR) genes. This study investigated the characteristics of CRISPR-Cas systems in E. faecalis from commercial broiler farms and assessed the impact of these systems on AMR.2. All E. faecalis isolates contained CRISPR2, and CRISPR1-Cas and CRISPR3-Cas were identified in 84 (56.4%) and 144 (96.6%) isolates. A combination of CRISPR2 and CRISPR3-Cas and a combination of CRISPR1-Cas, CRISPR2 and CRISPR3-Cas were each identified in 27 (96.4%) farms.3. There were significant differences between CRISPR-Cas systems for phenotypic AMR: CRISPR1-Cas and CRISPR3-Cas. The E. faecalis isolates without CRISPR1-Cas showed higher resistance to most antimicrobials and had a higher prevalence of multidrug resistance (MDR) than those with CRISPR1-Cas. However, the resistance rate against most antimicrobials and the prevalence of MDR did not differ significantly depending on the presence or absence of CRISPR3-Cas.4. The E. faecalis isolates without CRISPR1-Cas harboured higher levels of all AMR genes, except for tetL, than those with CRISPR1-Cas. However, the E. faecalis isolates with CRISPR3-Cas showed a significant lower prevalence of tetL gene and a significantly higher prevalence of fexA and poxtA genes.5. In the distribution of rep families, the rep₉ family was predominant, followed by rep₁, rep₇, rep₂ and rep₈ families. Only prevalence of the rep₇ family was significantly higher in the E. faecalis isolates without CRISPR1-Cas (15.4%) than in those with CRISPR1-Cas (0%).6. This study is the first report on the characteristics of CRISPR-Cas systems in E. faecalis isolated from commercial broiler farm environments, and the results supported the hypothesis that the development of antimicrobial strategies requires an understanding of the distinctive capabilities between CRISPR1-Cas and CRISPR3-Cas and their underlying resistance mechanisms.

1. This study investigated antimicrobial resistance, virulence factors and genotypic profiling among Proteus mirabilis isolated from three sources (poultry farms, slaughterhouses and retail markets) in the poultry production chain in Zhejiang Province, China, to assess its potential risk to public health.2. A total of 112 P. mirabilis strains were isolated from 409 samples, including 35 from poultry farms, 35 from slaughterhouses and 42 from retail markets. Antimicrobial susceptibility was tested using 18 antimicrobials in 9 categories, in which 110 (98.2%) strains were considered multidrug-resistant (MDR). These strains carried numerous antimicrobial resistance genes, with the sulphonamide resistance gene (sul1) having the highest rate (100%) and the polymyxin resistance gene (mcr-1) the lowest (3.6%).3. These isolates were validated to carry virulence genes pmfA, mrpA, atfC, rsbA, atfA, ureC and ucaA with the high prevalence of 96.4, 92.9, 92.0, 85.7, 85.7, 57.1 and 46.4%, respectively. Genotyping results using the ERIC-PCR indicated that the genetic similarity of all the isolates was 68.6% to 100% which fell into 4 clusters.4. The P. mirabilis isolates from the slaughterhouses exhibited higher levels of antibiotic resistance and a more pronounced MDR phenomenon than those from poultry farms and retail markets. The proportion of isolates carrying the most commonly detected resistant and virulence genes was higher in samples from poultry farms and slaughterhouses as opposed to retail markets. Importantly, there was genetic similarity and heterogeneity among P. mirabilis isolates from the three sources and genotypic diversity was the highest among isolates from retail markets, followed by slaughterhouses and poultry farms.

1. A total of 90 healthy Hyline brown laying hens (44 weeks old) were randomly assigned into three groups, a group of hens with fatty liver haemorrhagic syndrome (FLHS) fed with high-energy low-protein diet (HELPD), which exacerbates the syndrome, and the other two groups fed with HELPD containing 400 and 800 mg/kg PSP, respectively, to investigate the therapeutic effects and underlying mechanisms of Polygonatum sibiricum polysaccharides (PSP) on FLHS.2. Dietary PSP supplementation significantly elevated laying rate of FLHS hens. The FLHS hens fed with PSP displayed significant decrease in ALT, AST, TG, TC and LDL-C, while the increase in ALB, TP and HDL-C compared with FLHS hens.3. Hens receiving PSP had significantly reduced levels of MDA but increased activity of T-AOC, SOD, CAT and GSH-Px in both the serum and liver of hens with FLHS. It inhibited inflammatory response in FLHS hens, as evidenced by reduced levels and expression of IL-1β, TNF-α and IL-6, but elevated levels and expression of IL-10 in the serum and liver.4. Transcriptome analysis confirmed that PSP improved FLHS in laying hens through regulating lipid metabolism (such as PPAR signalling pathway, fatty acid metabolism and fatty acid biosynthesis), redox balance (including FoxO signalling pathway and peroxisome) and inflammation (e.g. adipocytokine signalling pathway and cytokine-cytokine receptor interaction).5. This study indicated that dietary PSP supplementation is a practical strategy to prevent and treat FLHS through improving lipid deposition, oxidative stress and inflammation in laying hens.

1. The global diversity of domestic chicken breeds, each exhibiting unique and specialised traits, offers a compelling context to explore how selection influences genetic variation patterns. China, with its myriad local chicken breeds, contributes significantly to this diversity.2. This study presents a population genome overview of genetic variations in 35 domestic chickens encompassing two distinct breeds from the Liangshan Prefecture in Sichuan Province. Through comparative genomic analysis of 17 red jungle fowls (RJF), genes associated with artificial selection in the Yanying and Luning chickens were identified. Further transcriptome comparison between these two breeds with Lohmann layers identified expression profiles of genes under selection.3. In total, 1,006 and 982 selected genes were identified in Yanying and Luning chickens, respectively, with 326 shared genes. These genes were primarily involved in immunity, energy metabolism, body size maintenance, and fertility. Transcriptomic analysis revealed tissue-specific gene expression, with Yanying showing immunity-related gene upregulation in ovaries compared to Lohmann chickens.4. These findings provide valuable insights into the genetic basis of breed-specific traits, offering potential targets for future breeding programmes to enhance chicken productivity and adaptability.

1. Ovarian follicle development is a key determinant of egg production in quail which is regulated by a dynamic and stage-specific genetic program. However, most follicle-related genes and miRNAs have not yet been identified in quail.2. This study applied transcriptome sequencing to dissect mRNA and miRNA expression patterns in quail ovarian follicles at distinct developmental stages: the pre-selection (SYF), the post-selection (F5) and the pre-ovulatory follicles (F1) in egg-laying birds. Comparative analyses identified 362 differentially-expressed mRNAs and 13 miRNAs in the F1 vs. F5 comparison, 549 and 72 in the F5 vs. SYF comparison and 1833 and 55 in the F1 vs. SYF comparison, respectively.3. Significant differentially-expressed mRNAs implicated in follicle development included VCAN, FGFR3, ALDH1A1, NR0B1,ZP2 and SMOC1. Other significant miRNAs were represented by ga-miR-460b-5p, gga-miR-1552-5p, gga-miR-125b-5p, gga-miR-135a-5p, gga-miR-122-5p, gga-miR-29b-3p and ggga-miR-138-1-3p.4. Enrichment analyses using GO and KEGG databases highlighted the influence of the extracellular matrix (ECM), cell adhesion molecules (CAMs), TGF-β and calcium signalling pathways and the steroid synthesis pathway on follicular development.5. Additionally, the miRNA-mRNA interaction network pinpointed the regulatory roles of specific differentially expressed miRNAs (DE miRNAs), including gga-miR-1306-5p, gga-miR-133a-3p, gga-miR-133c-3p, gga-miR-214, gga-miR-214b-5p and gga-miR-34a-5p.

1. This study evaluated the effect of acidified drinking water on the gastrointestinal function and intestinal health of broilers.2. A total of 630 one-day-old male broilers (Arbor Acre) were randomly assigned to one of three treatment groups: drinking water treatment (CON), drinking water + 0.5 ml Selko pH®/L (Selko pH), or + 0.85 ml Forticoat®/L (Forticoat) treated groups. Performance data, gut and digesta samples were collected from the broilers at the age of 21 and 42 d.3. The results showed that acidifying drinking water had no significant effect on body weight or average daily gain (ADG). However, addition of Forticoat significantly increased (p < 0.05) feed conversion ratio (FCR) throughout the experimental period and significantly increased (p < 0.05) pepsin activity on d 21. The Selko pH supplemented drinking water significantly increased (p < 0.05) the relative length of the duodenum and jejunum on d 21. The relative length of the jejunum and caecum on d 42 compared to birds receiving CON. The addition of the Forticoat to drinking water significantly increased (p < 0.05) the relative length of the jejunum and caecum on d 42 than for samples from birds in the CON group. In the caecal chyme, abundance of Blautia, Bifidobasterium, Faecalibacterium, Limosilactobacillus and Akkermania spp. on d 21 were significantly higher (p < 0.05) in the caecum of birds receiving Selko pH than those in CON group and the number of Escherichia Shigella in Selko pH and Forticoat group were significantly lower (p < 0.05).4. Overall, adding Seiko pH and Forticoat to drinking water improved pepsin activity, reduced the number of caecal pathogens, increased the number of beneficial bacteria and improved intestinal health in broilers.

1. This study evaluated the effect of oil-in-water (o/w) emulsion supplementation in feed compared to a conventional oil and emulsifier combination on fat and protein digestibility and growth performance in broiler chickens. The effects of this supplementation on macronutrient digestion kinetics were investigated through simulated in vitro digestion based on the broiler gastrointestinal tract.2. A total of 450 one-d-old Ross 308 chickens were assigned to one of the five dietary treatments consisting of nine replicates of 10 broilers each. The treatments included a control diet containing oil (3.25%) without emulsifiers, (NON-EM Low) or with a low emulsifier inclusion (0.10%), an EM Low diet supplemented with o/w emulsion using a low emulsifier concentration (3.25% oil; 0.10% emulsifier), a NON-EM High diet supplemented with oil (3.25%) and a emulsifier at high inclusion (0.65%) or a EM High diet supplemented with o/w emulsion using emulsifier at high inclusion (3.25% oil; 0.65% emulsifier). The feeding trial lasted 21 d using growing broilers.3. Body weight gain was higher in o/w emulsion diets EM Low and High compared to the other three diets. Fat digestibility at 21 d of age was not significantly different, although protein digestibility was lower in birds fed EM Low and EM High diets.4. In vitro digestion was substantially different in lipolysis, protein and starch hydrolysis kinetics. O/w emulsion supplementation reduced lag times in lipolysis and starch digestibility, and adding emulsifier altered the overall protein and lipid digestion kinetic behaviour.5. In conclusion, this study showed that o/w emulsion supplementation significantly improved broiler performance, most likely caused by differences in nutrient digestion kinetics in the starter phase. This research showed the potential of in vitro simulation to complement in vivo trials to understand digestion kinetics or to perform screening of potential diets before performing in vivo trials.

1. A study was conducted to investigate the effect of spermidine on cuproptosis in granulosa cells of goose ovarian follicles. Granulosa cells from F2-F5 grade follicles of Sichuan white geese were isolated and cultured.2. Copper sulphate, spermidine and chloroquine were administered to granulosa cells (GC). The GC activity, intracellular Cu²⁺ content, antioxidant enzyme activity, expression levels of genes and proteins related to autophagy and cuproptosis were determined.3. The results showed that spermidine significantly decreased reactive oxygen species (ROS) levels, mitochondrial membrane potential and Cu²⁺content (p < 0.05), and significantly increased the granulosa cell activity (p < 0.001). At the same time, spermidine significantly decreased the expression levels of ferredoxin 1 (FDX1) gene (p < 0.001), lipoylated-dihydrolipoamide S-acetyltransferase (Lip-DLAT) protein (p < 0.05), and increased the expression levels of LC3 gene (p < 0.001). After the cells were treated with spermidine mixed with chloroquine for 8 h, the cells were treated with copper sulphate, and GC activity was significantly decreased (p < 0.001). The expression levels of p62 and FDX1 genes were significantly increased (p < 0.01) and protein levels of LC3 and p62 were significantly increased (p < 0.05).4. In summary, spermidine reduced ROS accumulation, improved mitochondrial membrane potential and increased granulosa cell activity. It alleviated copper sulphate-induced lipoylated protein aggregation and cuproptosis in GC by inducing autophagy. This suggested that spermidine has a broad application prospect in alleviating cuproptosis in GC.

1. The objective of this study was to ascertain the impact of dietary calcium (Ca) and non-phytate phosphorus (nPP) levels that were progressively reduced in feed on performance, carcase, tibia traits and jejunum crypt depth and villus height in broilers.2. For the purposes of this study, 480, one-day-old chicks were randomly distributed into four treatment groups, with eight replicates per group and 15 birds per replicate. The starter period consisted of two different diets; the control diet contained 0.96% Ca and 0.48% non-phytase phosphorus (nPP) and the L-nPP diet contained 0.90% Ca and 0.45% nPP. The grower and finisher periods consisted of four different diets, namely control, L-nPP1, L-nPP2 and L-nPP3. The Ca contents of the control, L-nPP1, L-nPP2 and L-nPP3 diets during the grower period were 0.87%, 0.83%, 0.79%, 0.75% and the nPP contents were 0.44%, 0.42%, 0.40%, 0.38%, respectively. In the finisher period, the Ca contents of the control, L-nPP1, L-nPP2 and L-nPP3 diets were 0.78%, 0.71%, 0.60%, 0.50% and the nPP contents were 0.39%, 0.35%, 0.30%, 0.30%, respectively.3. Dietary treatments had no effect on body weight or body weight gain; however, a decrease was observed in the L-nPP2 and L-nPP3 diet groups compared to the control group over the 11-24 d period.4. No significant differences were observed in terms of tibial diameter, wall thickness or cross-sectional area. However, tibial ash and shear force were significantly lower in all groups with reduced Ca and nPP levels compared to the control group. The group fed the L-nPP3 diet exhibited a significantly higher crypt depth in comparison to the control and L-nPP1 groups, which was accompanied by a lower ratio of villus height to crypt depth.5. Wheat and maize-based broiler diets can be fed with 23% reduced Ca and nPP levels of recommended values without adversely affecting growth performance but may compromise skeletal health and intestinal histomorphology of broilers.

1. This study investigated the effects of Aronia melanocarpa pomace (AP) supplementation on serum variables, egg quality, laying performance, nutrient utilisation and gut microflora in late-stage laying hens.2. A total of 288 Hy-Line Brown hens (60 weeks old) were randomly allocated to one of four groups: a control (basal) or the basal diet supplemented with either 1% AP (APL), 2% AP (APM), or 3% AP (APH) for 20 weeks. Each group contained six replicates of 12 hens.3. Egg production, egg mass and shell thickness increased with AP supplementation, peaking in the 3% AP group (p < 0.05). The AP supplementation significantly reduced serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and aspartate aminotransferase (ALT) concentrations, with the greatest reductions observed in the 3% AP group (p < 0.05). Linear decreases in TG, TC and LDL-C were more pronounced in the 2% and 3% AP groups (p < 0.05). Linear improvements in calcium metabolism were observed in AP groups compared to the control group (p < 0.05).4. Crypt depth decreased in the duodenum, jejunum and ileum (p < 0.05), while the villus height-to-crypt depth ratio increased in the duodenum and ileum (p < 0.05), with a similar trend for the jejunal samples (p = 0.092). The AP supplementation increased beta diversity of caecal microbiota. At the genus level, Megamonas and Olsenella spp. abundance rose (p < 0.05), while Barnesiella spp. decreased (p < 0.05).5. Supplementation with 3% AP enhanced laying performance and egg quality in late-stage hens by improving lipid metabolism, calcium utilisation and gut microbiota composition. These findings highlighted AP as a functional feed additive for sustainable poultry production.