British Poultry Science最新文献

1. Two concurrent experiments were conducted to investigate the effect of using the crude protein (CP) value of supplemental amino acids (AA) in formulating reduced-crude protein (RCP) diets. The RCP diets formulated without accounting for CP values of supplemental AA (RCPN) or otherwise (RCPY) or a positive control (PC) diet were fed without (Experiment 1) or with (Experiment 2) phytase.2. Each experiment utilised 105 male broiler chicks. Birds were provided a common starter diet from d 0-7. On d 21, ileal digesta were collected from the distal half of the ileum. For mRNA expression analysis, tissues were collected from the mid-jejunum and the liver. Excreta grab samples were collected for analysis for N content.3. In Experiment 1, there was a stepwise decrease (p < 0.01) in weight gain and excreta N for birds receiving PC, RCPN and RCPY diets. The coefficients of ileal digestibility of His, Leu, Phe and Trp were greater (p < 0.05) in birds that received RCPY rather than the PC diets. The relative mRNA expression of CAT1 was greater (p < 0.05) for birds that received the PC diet.4. In Experiment 2, growth performance and excreta N were not different between the PC and RCPN diets, but weight gain, feed intake and excreta N were greater (p < 0.01) in birds receiving PC or RCPN diets. The coefficients of digestibility were greater (p < 0.01) in RCP than PC diets for Lys, Thr, Cys, Gly and Ser. The mRNA expression for S6kinase and PRKAβ2 was greater (p < 0.05) for birds fed RCPN compared to PC.5. In conclusion, accounting for the N content of supplemental AA during feed formulation for RCP diets will influence the effect of CP reduction on growth performance and ileal amino acid digestibility.

1. Dietary electrolyte balance (DEB) has been used to minimise problems in broiler chickens raised in warm climates. However, there is a need to determine the most appropriate DEB levels in these animals2. This study evaluated the influence of five DEB levels (110, 175, 240, 305 and 370 mEq/kg) on water intake (WI), zootechnical performance (feed intake, weight gain and feed conversion ratio), tibiotarsus bone variables (fresh bone weight, dry bone weight, bone length, mineral matter, Seedor index and bone strength) and intestinal histomorphometry (villus height (VH) and width (VW), crypt height (CH) and width (CW), internal and external muscularis) on broilers in two developmental phases (1-21 and 22-42 d of age). Additionally, the haematological profile (blood count and serum biochemistry), carcass yield, cuts and abdominal fat were assessed.3. Applying 370 mEq/kg DEB increased WI, VW in the jejunum and ileum and number of haemocytes at 21 d, while WI and VW in the duodenum and ileum at 42 d. In contrast, 110 mEq/kg increased chlorine concentrations at 21 d and leukocyte and heterophil numbers at 42 d.4. In summary, the 370 mEq/kg level was the most appropriate for broiler homoeostasis raised under natural heat stress, as the best results were found on WI and VW variables. Therefore, this DEB level was recommended in broilers aged 21 or 42 d.

1. The present study assessed the effect of different antioxidants on the quality of chilled/frozen-thawed sperm of red-legged partridge.2. Sperm samples from 40 red-legged partridges were collected and extended 1:1 (v:v) with Lake and Ravie 84, supplemented with ascorbic acid or butylated hydroxytoluene (BHT) at 0, 0.2, 0.4, 0.8 mM and catalase (CAT) or superoxide dismutase (SOD) at 0, 100, 200 and 300 IU/ml. Ten sperm samples were used per concentration. Motility and viability were evaluated in fresh and after 6 h of chilling at 5°C or after freezing-thawing.3. For chilled sperm, the presence of ascorbic acid decreased viability and several motility variables; BHT 0.8 mM increased non-progressive motility (NPM, 26.7 ± 1.99 vs. 20.7 ± 2.12); CAT 200 IU/ml improved the rectilinear velocity (40.4 ± 4.63 μ/s vs. 29.9 ± 4.62 μ/s) and linear progression ratio (52.8 ± 3.11% vs. 45.4 ± 2.98%); SOD 100 IU/ml increased NPM (24.5 ± 1.21% vs. 19.3 ± 1.75%) and tended to improve total progressive motility (42.7 ± 3.33% vs. 33.2 ± 3.26%, p = 0.07). Using an extender supplemented with CAT 200 or SOD 100 did not improve the post-thawed sperm quality.4. The present work provides an advance in the optimisation of chilling and freezing protocols for red-legged partridge sperm.

1. The amount of calcium and phosphorus in the empty, feather-free bodies of Cobb 700 breed males and females was measured from hatch to 15 weeks of age.2. A four-phase ad libitum feeding programme was used to feed 400 chicks of each sex. Feeds contained commercial levels of calcium and phosphorus which met or exceeded the requirements for energy, protein and amino acids. All birds were weighed weekly. Ten birds per sex were sampled at 0, 7, 14, 28, 42, 56, 70, 84 and 105 d of age. Defeathered birds were minced, freeze-dried and then analysed for protein, ash, calcium and phosphorus content.3. Amounts of Ca in males and females at 105 d averaged 54 and 37 g, respectively, and 105 d P content in males and females averaged 35 and 27 g, respectively. The allometry of ash, Ca and P with empty, feather-free body protein was assessed. Ash was isometric with body protein, while an allometric exponent greater than 1 was established for Ca and P with body protein.4. The allometric models and means for Ca and P relative to body protein were compared with models and means found in the literature. Comparison of the Ca/protein ratios with previous data suggested that modern broilers may not reach their potential bone mineral deposition with current dietary guidelines, even when growth rates were maximised.5. Theoretical allometric relationships between Ca and P in bone and bone-free body and body protein have now been proposed. The allometric relationship between Ca and P and empty, feather-free body protein offers a suitable way to model the growth of these minerals in the broiler body.

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. 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. In the following experiment meat quality traits of a Gushi-Anka F2 resource population were measured, and their heritability estimated. Intramuscular fat (IMF) had medium heritability (0.35) but leg muscle fibre density (LMD), leg muscle fibre diameter (LMF), breast muscle fibre density (BMD), fresh fat content (FFA), and absolute dry fat content (AFC) had low heritability (0-0.2). The IMF presented the most important genetic additive effect among the poultry meat quality-related traits studied.2. The phenotypic data of meat quality traits in the Gushi-Anka F2 resource population were combined with genotyping by sequencing (GBS) data to obtain genotype data. Six meat quality traits in 734 birds were analysed by GWAS. Based on these variants, 83 significant (-log₁₀(p) > 4.42) single nucleotide polymorphisms and four quantitative trait loci (QTL) regions corresponding to 175 genes were identified. Further linkage disequilibrium (LD) analysis was conducted on chromosome 13 (Chr13) and chromosome 27 (Chr27) QTL regions.3. Based on the transcriptome data and GWAS results, 12 shared genes - ITGB3, DNAJC27, ETV4, C7orf50, FKBP1B, G3BP1, IGF2BP1, KCNH6, LOC416263, SCARA5, SMIM5 and TBL1XR1 were identified as candidate genes influencing muscle fibre and fat traits.

1. Preventing disease is important in poultry production systems, but this has mainly been studied in chickens. The aim of this study is to explore the impact of microbial aerosols in intensive goose house environments.2. To evaluate the environmental quality of geese housing, fine particulate matter (PM2.5) was collected using an ambient air particulate matter sampler. High-throughput sequencing was used to analyse bacterial diversity and relative abundance. Results showed that the number of general and operational taxonomic units (OTUs) were 1,578 and 19 112 in all PM2.5 samples. Firmicutes, Bacteroidota, Proteobacteria, Acidobacterota were the four most abundant phyla in PM2.5.3. Compared with bacterial phyla in the PM2.5 from chicken houses, those in the genus Acidobacterota were increased in goose housing. There are various genera of bacteria present in PM2.5, and their composition was similar across different samples. No significant change was observed in the diversity of microbiota in the PM2.5, although multiple pathogenic bacteria were detected.4. A prediction function showed that a variety of bacterial phyla correlated positively with the human diseases.5. In summary, the microbial aerosols in the goose shed pose significant risks to the health of the geese. Regular monitoring of the composition of microbial aerosols is important for the healthy growth of geese and disease prevention and control.

1. The production of goose eggs holds significant economic value on a global scale and the quality of fertilised eggs is crucial for the successful hatching and sustained development of the poultry industry. Developing a low-cost fertilised egg identification system that is suitable for large-scale testing is of great significance. However, existing methods are expensive and have high environmental detection requirements, which limit their promotion.2. To address this issue, an improved object detection model called FEDM based on YOLOv5 is proposed, which has been shown to be outstanding among nine models. The main network of YOLOv5 is enhanced with the SENet attention mechanism to improve the feature selection capability. The C3_DCNv3 is introduced to enhance the detection ability of blood vessels in the fertilised eggs. The application of Dyhead significantly improved the representation capacity of the object detection head without any computational overhead. The loss function is replaced with MPDIoU to simplify the calculation process.3. Experimental results from the augmented dataset showed that the average precision of the FEDM reached 96.7%, which is a 5.5% improvement compared to the YOLOv5s model. FEDM exhibited better detection performance on eggs from different shooting angles than the YOLOv5 algorithm and achieves high detection speed.4. The FEDM secured significant advancement on the detection rate of the fourth day fertilised egg compared to the YOLOv5 algorithm. Based on this result, savings and space utilisation can be made, which has practical application value.

1. This study evaluated the efficacy of maize differing in particle size in low-density protein diets on performance, the digestive tract and litter characteristics in broilers. Four dietary treatments; control commercial diet with a typical crude protein content 22.50% (CON); CON + 20% maize with particle size 350 µm (M350), crude protein 19.90%; CON + 20% maize with particle size 2600 µm (M2600), crude protein 19.90%; CON + 20% whole maize (WM), crude protein 19.90%, were fed ad libitum to broiler chicks up to 21 d of age.2. No differences in body weight gain, feed intake and FCR were found between the WM and CON. WM increased body weight gain compared to M350 and M2600. M350, M2600 and WM increased (p = 0.004) gizzard relative weight compared with CON on day 14. Both WM and M2600 reduced (p = 0.001) gastric isthmus diameter on d 14 and 21 compared with CON and M350.3. No differences were seen in mucosa for the Lamina propria and the extent of Tunica muscularis of gizzard on d 21 and ileum mucosal depth on d 14 between WM and CON diets. However, WM reduced villus-to-crypt ratio compared with CON on d 21. The M350 reduced (p < 0.05) gizzard digesta particle size compared with CON, M2600 and WM on d 14.4. Both WM and M350 decreased (p < 0.05) nitrogen excretion compared to birds fed CON. Feeding WM increased nitrogen efficiency compared with M350 and M2600 diets, but was similar to birds fed CON. Feeding M350, M2600 or WM decreased (p < 0.05) litter moisture and footpad dermatitis (FPD) scores compared with results from birds fed CON.5. Overall, diluting the protein level in broiler diets with whole maize appeared better than fine or coarse maize in terms of growth performance, digestive tract development, nitrogen excretion and litter parameters. This may lead to economic benefits by reducing grinding costs and dependence on rich protein resources contributing to sustainable meat production and food security.