British Poultry Science最新文献

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. The heritability (h²) of liveweight (LW) in ostriches can be highly variable, depending on age at recording. The objective of this study was to consider random regression (RR) as an alternative to the multi-trait (MT) structure for the analysis of repeated measures of LW.2. The data included 74 683 LW phenotypes recorded from 10 052 birds aged between 20 and 410 days (d) of age. Statistical analysis included single trait (ST), MT and RR analysis in a linear mixed model framework using the ASREML V4.2 software.3. For ST and MT, six traits were defined to represent LW at 28, 77, 150, 230, 300 and 365 d of age. Random variance components included direct genetic and maternal permanent environment (PE) effects. A MT analysis including all six traits converged.4. For RR, the data was transformed (LW + 10)^-0.5 due to difficulty in dealing with large scale effects. The final RR model fitted direct genetic and animal PE components as third degree Legendre polynomials and heterogeneous residuals.5. The h² estimates was in agreement across analysis, ranging from moderate (0.16-0.20) for W28 to high (0.41-0.51) for W230 to W365. Importantly, the genetic relationship between LW recorded as a chick and juvenile was only moderate (~0.35 to 0.55). The correlations between RR and MT EBVs for the six traits were 0.85, 0.54, 0.65, 0.75, 0.83 and 0.91, showing a considerable level of re-ranking.6. This study reaffirmed age dependent genetic variation when determining LW in ostriches. The RR structure was useful for overcoming the dimension problem of MT analysis, but was susceptible to scale effects present in the data, despite transformation. It remains unknown whether the need for cubic terms reflected scale or animal effects.

1. This review was conducted to examine the nutritional composition of microalgae and their effects as a feed ingredient in poultry diets, delving into their influence on the production and quality of meat and eggs. Data collection focused on peer-reviewed scientific articles, with no limitation on the temporal horizon.2. Regarding nutritional composition, the collected papers indicated that certain microalgae species have a rich nutritional composition, with approximately 50% of their biomass composed of proteins. They contain a high concentration of EPA and DHA, important fatty acids that are found in low concentrations in conventional feedstuffs, and the presence of carotenoids such as beta-carotene.3. Incorporating microalgae into the diet of poultry can improve performance variables, such as mortality, live weight and feed conversion rate. It promotes benefits in meat and egg quality, with reduced cholesterol, increased EPA and DHA, intensified colour and higher concentration of carotenoids.

1.During transport of broilers from farms to slaughterhouses, the interior of crates may become contaminated with faeces. When these crates are not cleaned and disinfected adequately, they pose a potential risk for the dissemination of pathogens, including Campylobacter spp., between slaughterhouses and farms.2. The aim of the trial was to compare the efficacy of immersion-based crate washing systems with a spray-based washing system in reducing Campylobacter spp. Therefore, the crate washing systems in two slaughterhouses were sampled. In one of these two slaughterhouses, the immersion-based crate washing system was replaced by a new spray-based system which was sampled. Samples were collected from the slaughterhouse equipment, the crate washing system as well as from the crates both before and after cleaning and disinfection (C&D). All samples were screened for the presence of Campylobacter spp.; water and crate samples were used for enumeration. Molecular typing was performed to investigate the source and routes of contamination.3. In all cases, crates were contaminated with Campylobacter spp. prior to washing. However, only the spray-based system achieved a significant reduction after C&D Molecular typing revealed that the same strains were present on the crates after C&D as before cleaning. Additionally, crates could become contaminated by previously cleaned crates via wash water in the immersion-based crate washing system.

1. It remains unclear whether slow-growing broilers actually represent an overall animal welfare improvement - a major knowledge gap for policymakers and animal welfare NGOs. This paper addresses this knowledge gap by using an economic model to produce an all-things-considered estimate of the welfare effects of slow-growing genotypes. A quantitative end-point welfare metric that accounts for welfare challenges throughout the production cycle used the Pain-Track method from the Cumulative Pain Framework.2. Longer lifespans of slow-growing broilers (relative to fast-growing broilers) typically caused an increase in the time spent in low-intensity negative affective states. However, despite the additional broilers being farmed and their longer growth period, switching to slow-growing genotypes caused a decrease in higher-intensity negative affective states - a major win for welfare.3. These results can be used to alleviate consumer and producer concerns that any transition causes a welfare risk and provide an optimistic understanding of the overall welfare impact of transitioning to slow-growing broilers.

1. Avian Escherichia coli (E. coli) causes significant losses in livestock by inducing morbidity and mortality. Erythrocytes, the most abundant in blood, possess dual functions of oxygen transportation and immune regulation. In recent years, the interaction between erythrocytes and the complement system has gradually become a focal point of study. However, the transcription dynamics of the complement system in chicken erythrocytes post-E. coli invasion remains unclear.2. In this study, chicken erythrocytes and E. coli were co-cultured for 0.25-2 h to assess adhesion, analysed by indirect immunofluorescence (IIF) and scanning electron microscopy (SEM). Quantitative real-time PCR (qRT-PCR) examined differential expression of complement genes (CD93, C1q, C1s, C2, C3, C3AR1, C4, C4A, C5, C5AR1, C6, C7, C8G, CFI, MBL) in vitro using erythrocytes at 0.25-2 h and in vivo using chicks at 1, 3 and 7 d post-E. coli infection.3. E. coli adheres to chicken erythrocytes, as observed using IF and SEM. Gene expression analysis revealed early downregulation of C4, C4A, MBL and late upregulation of CD93, C1q, C1s, C3, C3AR1, C5AR1, C6, with C5, C7, C8G downregulated at 7 dpi. C2 expression varied at each time point.4. This study first showed E. coli adhering to erythrocytes, which activated complement genes rapidly. In vivo recovery from chickens with colibacillosis favours classical pathway activation, while lectin pathway may be inhibited, suggesting early immune down-regulation.

1. This study investigated the impact of different lairage duration on physiology, metabolism and meat quality in commercial broilers.2. A total of sixty, one-d-old Vencobb broilers were reared until 42 d of age and subjected to five lairage treatments (T0-T5), with the control with no lairage and then each timepoint increasing by 2 h.3. Head, eye and feet temperature increased progressively (P˂0.05), from 21 to 42 d. During lairage, temperature for the head, eye and feet were significantly higher in birds held until T3-T4 (P˂0.05), than at T0-T2 and T5 treatments.4. Serum total protein, creatinine, lipase and TBARS showed no variation due to lairage (p > 0.05). Glucose levels were highest at T4 (p < 0.05) than at T1-T3 or T5 and serum albumin increased only at T4 as compared to T5 (p < 0.05). Higher levels for blood triglycerides were recorded for T0, T1 and T5 (p < 0.05), than at T2-T4 and total blood antioxidants were significantly higher at T1 (p < 0.05), than at T0 and T2-T5 treatments, respectively.5. There was no significant difference for meat pH, ERV and WHC (p > 0.05), while, higher tyrosine levels (p < 0.05) were noted for birds in T5 than for the rest of the lairage treatments (T0-T4). On the same trend, TBA concentration was highest for birds in T5, as compared to T4 (p < 0.05).6. In conclusion, lairage over eight hours for commercial broilers is not recommended, as there are drastic changes in physiology, metabolism and deterioration of meat, reducing meat quality.

1. Lighting is a crucial environmental factor in poultry production. This study evaluated the effects of light-emitting diodes (LED) on performance and several bone characteristics, including bone mineralisation, morphometry, histology and selected gene expression in broiler breeders.2. A total of 800 one-d-old female broiler breeder chickens (Ross 308) were randomly allocated to one of 20 light-proof pens and reared under green (GL) or white (WL) LED light for two photophases (8 or 12 h) in a 2 × 2 factorial experiment and compared to a control group (incandescent lamp at 8 L:16D duration; CON). Weight gain, feed consumption and feed conversion ratio (FCR) were calculated. Femoral and tibial characteristics were measured.3. The LED colour affected feed intake during the rearing period, being higher for birds under white compared to green light. Tibial calcium (Ca) concentration in WL birds was lower than for green LED lighting regimens but not different from the CON group (p ≤ 0.05). Birds under 12 h lighting had greater tibia bone dry matter and trabecular separation (mm) than those in the 8 h groups. However, bone volume fraction and trabecular number per mm in 8 h birds were higher than in 12 h groups (p ≤ 0.01). There was greater expression of the osteocalcin gene under WL compared with CON. Osteopontin expression in WL8 was 4.63 times greater than in the CON group (p ≤ 0.05). The alkaline phosphatase gene expression in WL12 was higher than in the CON group (p ≤ 0.05).4. Exposure to white and green LED spectra enhanced bone gene expression and mineralisation, respectively, without adverse effects on bird performance. Thus, LED light may be beneficial to broiler breeder bone traits.

1. Erysipelas in geese and ducks is an infectious disease causing considerable economic losses in the poultry sector in Poland. The aim of this study was to determine the distribution of erysipelas cases in age groups of geese and in periods of the calendar year and to assess macroscopic lesions in birds infected with Erysipelothrix rhusiopathiae.2. The study used 286 geese and 16 ducks delivered to the laboratory for diagnosis in the years 2019-2021. The birds came from 99 different farms. E. rhusiopathiae from clinical samples were cultured on Columbia blood agar and identified by real-time PCR. Pathological lesions were characterised during anatomopathological examination.3. Distribution of erysipelas cases in age groups of geese and periods of the calendar year differed significantly from the assumed even distribution. Most cases were noted in August and September in birds aged between 11 and 13 weeks. Necropsy of birds infected with E. rhusiopathiae showed anatomopathological lesions characteristic of generalised infection, affecting multiple organs.4. The uneven distribution of erysipelas cases in geese in different age groups and periods of the calendar year suggested that both the age of the birds and climatic conditions are predisposing factors for infection.

1. This meta-analysis investigated the impact of LPS and covariates (serotype, rearing period and administration route) on the productivity parameters of broiler chickens (average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR)).2. Thirty-two eligible studies were included. Hedges' g effect size was determined using a random-effects model at 95% confidence interval.3. Results showed that LPS significantly decreased average daily feed intake (ADFI; p < 0.0001) and average daily gain (ADG; p < 0.0001) and increased FCR (p < 0.0001). The serotypes Escherichia coli 055: B5 (EC055: B5) and Escherichia coli 0127: B8 (EC 0127: B8) significantly reduced ADFI and ADG, and the serotype EC 055: B5 significantly increased the FCR (p < 0.05).4. The intraperitoneal administration of the LPS significantly reduced the productivity of broiler chickens (p < 0.05), but other administration routes did not show such effects. The reduction in ADFI and ADG was found in all rearing periods (p < 0.05), and the increase in FCR was observed in the starter (p = 0.0302) and grower periods (p = 0.0031).5. Exposure to LPS significantly reduced the productivity of broiler chickens (p < 0.05). However, no relationship was observed between LPS dosage and productivity as indicated by the meta-regression study.6. The findings indicated that LPS has detrimental effects on broiler chickens' ADFI, ADG and FCR across various LPS serotypes and rearing periods. These detrimental impacts of LPS remain consistent regardless of the administered dosage.