British Poultry Science最新文献

1. This study explored the combined effects of gelatin and l-arginine or l-lysine on cooking losses and the development of pale, soft and exudative (PSE)-like chicken sausages.2. The results indicated that gelatin, l-arginine or l-lysine singly ameliorated cooking loss from 17.8% to 12.2%, 9.5% and 8.3% augmented sausage hardness from 23.2 to 29.8, 29.8 and 27.0 N, and l-arginine or l-lysine elevated (p < 0.05) the cohesiveness of sausages, making them compact and uniform. Furthermore, they diminished total expressible liquid and expressible fat, augmented viscosity, storage and loss modulus in batter which had smaller and more uniform oil droplets. Adding Arg or Lys raised the pH of the batter, irrespective of gelatin addition.3. Overall, the combined treatments were more effective in changing meat batter and sausage properties than the single treatments. Therefore, gelatin and l-arginine or l-lysine worked synergistically and enhanced the emulsifying and gelling properties of PSE-like chicken, ameliorating the qualities of PSE-like chicken sausages.

1. In the contemporary economic-industrial world, ensuring the quality of poultry products through the use of healthy birds and providing nutritious diets has gained particular importance. The objective of this experiment was to evaluate the optimisation of laying hens' diets by reducing dietary protein by 4.61% and replacing it with 1.5 g/kg fermented wheat bran using two strains of Aspergillus niger and two strains of Aspergillus oryzae.2. This study was conducted on 240 laying hens at 41 weeks of age over 16 weeks, organised into four treatments and two control groups. One of the control groups included a diet with normal protein (CH) and another group with 4.61% less protein (CL). Both control groups received 1.5 g/kg raw wheat bran with their diet. In contrast, the four experimental treatments (N0, N4, O3, O4) received a diet with 4.61% less protein and 1.5 g/kg fermented wheat bran by their respective fungal strains, including two strains of A. niger-50101 (N0) and 92 844 (N4) and two strains of A. oryzae-5163 (O3) and 5164 (O4).3. The highest free radical scavenging activity, iron ion regenerative power and anticoagulant activity were observed in the control group containing uncultivated bran (p<0.05). A significant reduction in phytate content and an increase in total phenolic compounds in the fermented bran extract N4 fungi were observed (p<0.05). Additionally, this group showed the lowest level of egg yolk oxidation, as indicated by the induced malondialdehyde reaction.4. The N0 treatment had the highest feed intake and antioxidant activity in blood serum compared to the other groups (p < 0.05). The O4 group had the highest egg mass and egg weight, as well as the lowest levels of triglycerides and oxidation in the egg yolk compared to the other groups (p < 0.05).5. This study showed that fermenting wheat bran with Aspergillus spp. could enhance its antioxidant properties, which in turn improves egg quality.

1. Shifting to higher welfare systems is expected to increase their environmental impact and mitigation strategies need to be identified. The environmental impacts associated with various broiler production systems (BPS: conventional, higher welfare indoors, free-range or organic) and the characteristics of BPS which contribute to these impacts were investigated via a literature review and meta-analysis.2. The impact metrics considered were global warming (GWP), acidification and eutrophication potentials, NH₃ emissions, land use, water use, energy use (EU) and biodiversity. Due to the paucity of data, analysis was limited to the impacts of the characteristics of the BPS: stocking density (STD), slaughter weight (SW), feed conversion ratio (FCR), on GWP, NH₃ emissions and EU.3. After correction for system boundaries and functional units, no statistical effects of BPS on GWP were found, while higher welfare systems were associated with higher EU. Reduced STD was associated with reductions in GWP and EU. The SW was positively associated with GWP and NH₃ emissions, while higher FCR was associated with increased NH₃ emissions and EU.4. Environmental impacts arose from feed-associated activities (>75%). Most of the GWP impacts were associated with land use change (LUC), especially when associated with 'unsustainable' soya. High variation in values for different environmental metrics within BPS indicated a lack of standardisation in the assessment of environmental impact across the industry.5. The results suggested that practices within a system contributed greatly to the environmental impact of the system. Rather than comparing systems, it may be more productive to focus on improving practices that have the potential to reduce environmental impacts within a system, without compromising animal welfare.

1. Valgus-varus deformity (VVD) is a disease that severely affects leg function in broilers and for which there is no effective control method current available. Although DNA methylation has an important impact on most physiological and pathological processes, its involvement in skeletal muscle growth and development in VVD broilers is unknown. In this study, genome-wide DNA methylation was analysed in VVD-affected and normal broilers using whole genome resulphite sequencing.2. The results showed that in the cytosine-phosphoric acid-guanine (CG) sequence environment there was a methylation rate of about 55% and 4,265 differentially methylated regions (DMRs) were found in the CG. Of these, 550 were located in the promoter, 547 in the exon region, and 1,718 in the intron region.3. All differentially methylated genes (DMGs) were analysed for enrichment of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The GO was enriched in pathways related to protein degradation such as proteasome complex, endopeptidase complex and extracellular region. The KEGG pathways were enriched in signalling pathways related to protein degradation and catabolism such as proteasome, nitrogen metabolism, adherens junction and alanine.4. Protein interactions analysis revealed that FOS, MYL9, and FRAS1 had a high degree of interactions, in which the DNA methylation level of the MYL9 promoter region was negatively correlated with mRNA expression level. Further studies showed that 5-azacytidine (5-AzaC) inhibited DNMT1 and DNMT3A gene expression and promoted MYL9 expression.5. This study systematically investigated overall DNA methylation patterns in the leg muscle of VVD and normal broilers. It screened common differential genes in conjunction with transcriptomic data to further identify genes associated with muscle growth and development. This study provides new insights to better understand the pathogenesis of VVD from an epigenetic perspective.

1. The aim of this work was to identify a heritable keel bone phenotype with a correlation to keel bone damage and/or skeletal bone strength that could be easily measured in the living hen to aid selection to prevent welfare issues.2. The scoring system used reflected the observed damage, keel bone dimensions and shape compared to traditional measurements of bone quality.3. Increased keel bone damage was associated with poor humerus and tibia breaking strengths (p < 0.01). Bone damage was associated with higher whole keel density (p < 0.01) due to the effect of callus formation.4. Keel bone depth and area was moderately heritable at indices of 0.32 and 0.40, respectively. Keel bone depth was genetically correlated with tibia (0.36) and humerus density (0.68) and keel bone area was correlated with humerus density (0.59). Deeper keel bones and those with larger areas had small, negative phenotypic correlations with keel bone damage (-0.07 and -0.11, respectively). The second principal component of keel bone shape represented the caudal section of the keel bone and cranial edge concavity. The third principal component represented the differences in the caudal tip of the keel bone, the concavity of the dorsal edge and convexity of the ventral edge. Heritability estimates were 0.44 and 0.39, respectively.5. The results suggested that genetics contribute to morphometric traits. Hens with poorer skeletal quality are likely to accumulate more damage. Some of the traits may be a predictor of damage, although mid keel depth or concavity may simply reflect the effect of damage or deviation.

1. This study aimed to investigate the effect of the first and third parities and one male: four females (1 M:4F) and 1 M:6F sex ratios of White Roman geese on their reproductive performance and biochemical parameters in an environmentally controlled house.2. Ganders (n = 136) and geese (n = 656) from the first and third parity were randomly placed into eight pens. These eight pens were assigned to one of four treatments in a 2 × 2 factorial arrangement (two sex ratio groups × two parity groups). The first and third parity treatment groups had 1 M:4F (each pen containing 20 ganders and 80 geese) and 1 M:6F (each pen containing 14 ganders and 84 geese) sex ratio treatment groups, respectively, replicated twice.3. Blood samples were collected from the geese at different time points: upon entering the house (ST), the beginning of the lighting regime of 7 L:17D for six weeks (LC6W), lighting adjustment to 9 L:15D for 6 weeks (9C6W), the peak of egg production (PEP) and the end of egg production (EEP).4. The first parity group had a longer laying period than the third parity (274 vs.191 days). First parity had a lower egg production rate than third parity during whole stage (18.7 vs. 25.4%). Fertility in 1 M:4F group was significantly higher than in 1 M:6F rate group (54.7 vs. 45.1%) at all periods.5. Plasma levels of total protein, albumin, globulin, triglycerides, calcium and phosphorus concentrations were significantly higher for whole laying period in first parity geese compared to third parity birds.

1. An experiment was conducted to explore the age-related changes in carcass composition, physicochemical properties, texture and microstructure of meat from White King pigeons. The study used 32 carcasses collected from White King pigeons (16 aged 4 weeks and 16 aged 180 weeks).2. The 180-week-old White King pigeons had a higher percentage of eviscerated carcass characteristics. The 4-week-old pigeons were characterised by higher percentage of skin with subcutaneous fat and carcass remainders. There were significant differences in chemical and physicochemical characteristics as well as in texture and microstructure parameters amongst White King pigeons of different ages.3. In conclusion, the study demonstrated that the age of White King pigeons has a considerable impact on carcass composition, physicochemical properties, meat texture and microstructure. Older pigeons had higher percentages of eviscerated carcass components, which may reflect maturation, while younger pigeons had greater proportions of fat and carcass remainders. These findings suggest that age-related changes should be considered when evaluating meat quality and composition, as each age group presented distinct characteristics.

1. This study assessed the addition of dried stinging nettle (SN) leaves at 0%, 2.5% and 5.0% in feed on egg production, egg quality, chemical composition and antioxidant content in eggs from laying hens.2. Seventy-two Hy-Line Brown laying hens, housed in 36 enriched layer cages, were used in the study from 43 to 47 weeks of age. Feeding dry SN leaves did not affect (p > 0.05) egg production variables.3. Dietary SN inclusion linearly increased (p < 0.001) carotenoid content more than six-fold, in addition to yellowness and redness of the yolks at the maximum inclusion. Providing eggs from hens fed carotenoid enriched diets, e.g. SN, may be used to increase carotenoids in human diets.

1. The objective of the trial was to study the single and interactive effects of feed particle size in pelleted feed, dietary calcium (Ca) concentration and microbial phytase supplementation in broiler chickens. The studied traits were myo-inositol (1,2,3,4,5,6) hexakis (dihydrogen phosphate) (InsP₆) degradation, pre-caecal digestibility of phosphorus (P), Ca and amino acids (AA) and retention of P, Ca and nitrogen (N).2. Male Ross 308 broiler chickens were housed in metabolism units in groups of 10 and allocated to one of eight diets with seven pen replicates per diet. The 2 × 2 × 2-factorial arrangement included coarse and fine feed particle size (309 or 222 µm), low and high Ca concentration (4.9 and 7.2 g/kg) and without or with phytase supplementation (1,000 FTU/kg).3. Pre-caecal InsP₆ disappearance was higher with coarse than fine feed particle size when no phytase was added (54 vs. 48%) but not when phytase was added (74%; p = 0.046). High dietary Ca feeds decreased pre-caecal InsP₆ disappearance (67 to 59%) and P digestibility (65 to 55%; p < 0.001). Gizzard pH was lower with coarse than fine feed particle size and higher with high Ca than low Ca (p < 0.001). Pre-caecal digestibility of most AA was approximately 3.5%-points lower with high Ca without phytase compared to the other treatments (p ≤ 0.047). Coarse feed particle size caused higher pre-caecal AA digestibility than fine particle size (~2%-points; p ≤ 0.031). InsP₆ disappearance in the crop increased at high Ca concentration when phytase was added (22 vs. 37%; p = 0.011).4. Coarser feed particle size in pellets increased gastrointestinal InsP₆ degradation and nutrient digestibility, likely owing to effects on the gizzard functions. Additional Ca supply exerted antinutritive effects that was not compensated for by using coarser feed particles.

1. This study investigated the role of glutathione peroxidase 4 (GPX4), a key regulator of ferroptosis, a form of programmed cell death, in muscle biochemistry and meat quality, utilising broiler chickens whose ante-mortem GPX4 activity was inhibited pharmacologically.2. Male broilers were divided into two groups, each receiving ante-mortem administration of the GPX4 inhibitor, Ras-selective lethal 3 (RSL3), or a vehicle only. After slaughter, breast muscles were collected and stored for 48 h. The expressions of ferroptosis-related genes, glutathione levels, pH, colour and water-holding capacity were evaluated at multiple time points during the storage period.3. The RSL3 treatment decreased the expression of GPX4 and ferritin heavy chain 1, which are negative regulators of ferroptosis, while it increased the expression of a ferroptosis accelerator, acyl-CoA synthetase long chain family member 4. The ratio of reduced to oxidised glutathione was significantly decreased in the RSL3 group. The RSL3 treatment decelerated post-mortem pH decline and colour changes, such as a decrease in L* and an increase in a* were observed in the RSL3 group. In addition, the RSL3 group showed increased levels of water-holding capacity.4. These findings suggested that ante-mortem GPX4 activity plays a role in determining meat quality, implying the possible involvement of ferroptosis in the mechanism by which skeletal muscle is converted after slaughter into meat that is eaten.