British Poultry Science最新文献

1. Although the anti-inflammatory drug Ketoprofen has been used in ducks, there has been no research on its pharmacokinetics. This study examined the disposition kinetics and bioavailability of Ketoprofen in Pekin ducks after intravenous (IV), intramuscular (IM) and oral administration for the first time.2. A total of 18 ducks were split into three equal groups (n = 6) and were given a single dose of Ketoprofen (5 mg/kg) via IV, IM or oral routes. Blood samples were collected at 16 different time points up to 24 h post-administration to determine the change in Ketoprofen plasma concentration over time by high-performance liquid chromatography with ultraviolet detection.3. Following IV injection, total clearance, volume of distribution at steady state and elimination half-life were 0.31 l/h/kg, 0.32 l/kg and 0.95 h, respectively. Following IM and oral administrations, peak plasma concentrations of 13.82 and 6.76 μg/ml were attained at 0.34 and 0.48 h, respectively. Bioavailability was 106 and 63% for IM and oral route, respectively, and average plasma protein binding was 98.8 ± 2.4%.4. Ketoprofen showed small volume of distribution and rapid elimination in Pekin ducks. The IM injection resulted in higher plasma concentration and bioavailability than oral administration. This information contributes to the use of Ketoprofen in ducks in an appropriate dosage regimen, but efficacy needs to be demonstrated in experimental inflammation models.

1. The aim of this research was to explore the influence of overfeeding on goose meat quality in foie gras production. Forty Tianfu Meat Geese were averagely separated into normal-feeding group (control group) and overfeeding group (force-feeding group), randomly. After overfeeding, the breast muscle and leg muscle were collected, and then the determinations of meat quality variables were performed. The cluster analysis, principal component analysis (PCA) and partial least square-discriminate analysis (PL-SDA) were performed to comprehensively estimate the influence of overfeeding on goose meat quality.2. Overfeeding increased the weights of breast muscle and leg muscle (p < 0.05), increased L*, a* and b* values of breast muscle and leg muscle (p < 0.05), increased the hardness values of breast muscle and leg muscle (p < 0.05), decreased the cooking loss of breast muscle (p < 0.05). In nutritional variables, overfeeding increased the contents of crude fat of breast muscle and leg muscle (p < 0.05). In breast muscle, overfeeding increased the contents of Ala, Tyr, Lys and Val, and decreased the contents of Arg and Phe (p < 0.05); in leg muscle, overfeeding decreased the contents of Asp, Glu, Ser, Ala, Tyr, Val, Phe, Ile and Leu, and increased the contents of Arg, His and Lys (p < 0.05). In fatty acids composition, the contents of C14:0, C16:1, C16:0, C18:2n6c, C18:1n9c, C18:0 and C20:0 of breast muscle significantly increased after overfeeding (p < 0.05). PCA and PLS-DA suggested that overfeeding had significant influence on the meat quality of the breast muscle and leg muscle.3. In conclusion, overfeeding improved the meat quality of overfed geese.

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. Melan-A (MLANA) plays a key role in the development of the melanosome, making it a strong candidate for the pigmentation phenotype observed in animals. The main purpose of this study was to analyse the relationship between MLANA gene polymorphisms and tyrosinase (TYR) enzyme activity in skin tissues and melanin content in dorsal down feathers of Chinese yellow quail.2. The coding sequence region of MLANA mRNA was cloned and sequenced to detect polymorphisms. The melanin content in down feathers of 266 Chinese yellow quails was analysed by spectrophotometry, and TYR enzyme activity was measured in dorsal skin tissues. The expression of MLANA mRNA in skin tissues of individuals with different genotypes was analysed using RT-qPCR.3. One non-synonymous single nucleotide polymorphisms (NSSNP; c.218T/A) was identified, which resulted in a Leu36Val mutation in the transmembrane helix region of the MLANA protein. This NSSNP significantly reduced the expression level of MLANA mRNA and TYR enzyme activity in dorsal skin tissues, leading to a significant reduction in melanin content in down feathers.4. The c.218T/A locus of the MLANA gene is closely related to the pigmentation TYR of the down feathers in Chinese yellow quail and can be used as a molecular marker locus for breeding pure feather colour in quail.

1. E. coli is an opportunist pathogen of animals, including food-producing ones and humans. Chickens may be a notable source of pathogenic and antimicrobial resistant E. coli for transmission to humans.2. This study compared virulence-associated genes (VGs) and antimicrobial resistance (AMR) in avian pathogenic E. coli (APEC) and extraintestinal pathogenic E. coli (ExPEC) isolates from broiler chickens, specifically APEC isolates in liver samples (n = 78) and ExPEC or non-ExPEC isolates in litter samples (n = 34). Virulence was evaluated by PCR for feoB, hlyF, iroN, iss, iutA and ompT genes, while AMR was evaluated by using antimicrobials from seven classes and detecting bla_SHV, bla_TEM, bla_OXA, qnrB, stcM, mrc1, mrc2, sul1 and tetA genes.3. The APEC isolates were found in 100% of livers, while ExPEC and non-ExPEC isolates were found in 44% and 56% of the litter samples. The predominant VG was feoB (100%), followed by ompT (63%), iutA (60%), iss (58%) and hlyF (43%). Surprisingly, iroN, omp T and iutA had higher prevalences in APEC isolates (85%, 96% and 96%, respectively) than in ExPEC isolates (73%, 87% and 73%, respectively) and non-ExPEC isolates (0% for all). The presence of all VG in 33% of isolates indicated high pathogenicity.4. The isolates were phenotypically resistant to ampicillin (93%), ceftazidime (72%) and nalidixic acid (82%). All APEC and ExPEC isolates (100%) were multidrug resistant (MDR), while 63% of non-ExPEC isolates were MDR. Genotypic AMR testing revealed that 53% and 52% of all isolates had stcM and tetA, respectively. No isolate was positive for bla_SHV, bla_OXA, mrc1 or mrc2, which suggested the benefits of colistin for treating carbapenem-resistant enteric pathogens, due to the high resistance detected to meropenem (47%).5. Given the potential pathogenicity of E. coli isolates, improving biosecurity practices in chicken flocks should be prioritised to eliminate transmission to humans through the food chain.

1. Accurate sex identification of one-day-old chicks is crucial in layer poultry production. Establishing an early sexing method during the chicken embryonic period is essential for animal welfare. However, PCR-based sexing has limitations in terms of specialised equipment and is time-consuming.2. This study presents a rapid, simple and fluorescent visual technique for chicken sex identification based on Loop-mediated isothermal amplification (LAMP)-clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 12a (Cas12a). It targets the chicken Z chromosome gene DMRT1 and W chromosome-specific fragment EE0.6 using designed primers and sgRNA. The LAMP amplicon is cleaved by Cas12a, producing a fluorescent product detectable by a portable light apparatus.3. The method has high sensitivity, capable of detecting as few as two copies per microlitre of the EE0.6 template and 20 copies per microlitre of the DMRT1 template. This has significant potential for distinguishing chicken embryo gender very early in embryonic development.

1. The effects of feeding regimen, NSPase, extent of grinding and their interaction on the performance, digestive tract characteristics and ileal microbiota were studied. Eleven-day-old Ross 308 male broilers were given ad libitum (ADL) or intermittent (INT) access to finely (FG) or coarsely (CG) ground barley-based pelleted diets, with or without NSPase in a replicated pen trial. All birds had 4 h darkness separated with 1 h light periods with feed access. In addition, INT birds had access to feed through three 1 h feeding periods and one 2 h feeding period, with 3 h feed restriction periods in between.2. The INT feeding decreased weight gain (p < 0.001) but did not affect FCR. Supplementation with NSPase increased (p = 0.018) weight gain, but there was a tendency (p = 0.063) for it to be improved in INT-fed birds only. Including NSPase improved FCR, but only with FG diets (p = 0.037) and in INT group (p = 0.033).3. The CG diet significantly reduced (p = 0.044) pH of the gizzard contents and increased (p = 0.035) gizzard relative weight compared to FG. Addition of NSPase (p < 0.001) or FG (p = 0.049) reduced jejunal digesta viscosity. The FG diet improved (p = 0.019) starch digestibility compared to CG. In NSPase-supplemented diets, CG increased ileal protein digestibility compared to FG in birds fed ADL only, resulting in a three-way interaction(p = 0.012).4. The FG diet increased ileal concentration of total eubacteria and Lactobacillus spp. (p = 0.049), whilst INT feeding increased ileal concentration of Streptococcus spp. (p = 0.001). In NSPase-containing diets, FG increased ileal density of Enterococcus spp. in INT-fed birds (p = 0.027).5. In conclusion, finely-ground barley in pelleted diets responded better to NSPase enzymes than coarsely ground, particularly under INT feeding.

1. Further-processed poultry products, such as chicken nuggets, are susceptible to rapid lipid oxidation and microbial spoilage. Natural ingredients from various plants or fruits may contribute to improving the quality and extending the shelf life of meat products. In the present study, the use of encapsulated raspberry powder (ERP; control, 0.5%, 1.0%) in chicken nugget production with and without phosphate (0.0%, 0.3%) and its effects on chemical composition, lipid oxidation, microbial quality and shelf life were examined.2. Phosphate and ERP had effects on chemical composition and a_w; (p < 0.01). During storage, the ratio of O₂ and N₂ increased and the amount of CO₂ decreased (p < 0.05), but the increase in samples with 1.0% ERP addition was lower than in the control and 0.5% groups.3. Both the use of ERP (p < 0.01) and phosphate (p < 0.01) for nugget production prevented lipid oxidation. The lowest was determined in samples containing phosphate + 1.0% ERP (p < 0.05) during storage. However, the TBARS values were within acceptable limits (<1 mg MDA/kg) for all the samples with 0.5% and 1.0% ERP added with phosphate.4. The counts of total aerobic mesophilic bacteria decreased depending on the level of ERP added to the nugget composition (p < 0.01). Counts only exceeded 6 log CFU/g in the control samples on the 120^th day of storage. Salmonella spp. and Listeria monocytogenes were negative in all nugget samples during storage. The counts of Enterobacteriaceae were below the detectable limit (<2.0 log CFU/g) during storage.

1. The avian gut hosts a complex and dynamic microbial ecosystem, which is essential for regulating host organ function. However, the relationship between the gut microbiota and the hypothalamic axis in acute stress vulnerability in ducks remains unclear.2. This study investigated how the gut microbiota affects microbial metabolism and the host stress response by comparing hypothalamic neurotransmitter availability, microbial composition and co-metabolites generated by both the microbiota and hypothalamus in ducks exhibiting the lowest active avoidance (LAA) and highest active avoidance (HAA) behaviour.3. The HAA group experienced a significant increase in the availability of arginine, histidine, glutamine, norepinephrine, L-tyrosine and melatonin during acute stress in the hypothalamus, compared to that in the LAA group. The 16S rRNA sequencing revealed significant differences in the gut microbiota composition based on acute stress vulnerabilities.4. Both caecal and hypothalamic metabolomic analyses identified 71 metabolites altered in caecal content and 95 in the hypothalamus. There was significant enrichment in pathways such as the cGMP-PKG signalling, dopaminergic synapse and endocrine resistance.5. Correlation analyses demonstrated that certain co-metabolites, including 1,3-dicyclohexylurea, 1-deoxyvaleric acid, 2-amino-2-methyl-1,3-propanediol, 3-chloroaniline, methenamine, N4-acetylcytidine-triphosphate and traumatin, may play a role in the gut microbiota-hypothalamic axis.6. The results suggested that the gut microbiome influenced acute stress responses. This provided a basis for understanding gut-hypothalamic communication and its impact on behaviour in ducks.

1. In fast growing broilers, intestinal health is continuously under pressure due to extremely high feed intake and environmental/management conditions that cause (oxidative) stress to the intestinal epithelium.2. The following review focuses on the contributions of the Livestock Gut Health Team at Ghent University into understanding the mechanisms governing the interactions between the intestinal microbiota and the host intestinal mucosa. It covers the development of tools to support intestinal health of broilers through nutritional manipulation of the microbiota.3. In the duodenum and jejunum, microbiota are suppressed by the secretion of enzymes and antibacterial peptides in order to avoid competition for the nutrients. These defence mechanisms can be re-enforced and/or the epithelial cells can be protected from damage by different feed additives.4. Metabolism in the caecal microbial network is fuelled by the fibre fraction in feed. Whenever this network is incomplete or the feed is lacking fibre, this may lead to a distortion of the microbiota, followed by insufficient production of beneficial microbial metabolites, such as butyrate. This can contribute to inflammation and leakage of the gut barrier, with, in severe cases, wet litter, foot pad lesions and poor performance as common consequences. Reenforcing the caecal microbial network can be achieved using prebiotics, probiotics and postbiotics, which will improve the health and well-being of the birds.5. Steering towards optimal microbial fermentation will help to protect the birds from Clostridium perfringens-associated necrotic enteritis and Salmonella spp. colonisation since both interact with the intestinal microbiota.