British Poultry Science最新文献

1. This study investigated the effects of different housing systems on oxidative defence mechanisms, heterophil functions, cellular immune response and cytokine production in laying hens. One hundred and twenty laying hens were allocated into one of four groups: conventional cages, furnished cages, deep litter, and free range.2. Housing system did not affect malondialdehyde concentrations and enzymatic antioxidant status. Ascorbic acid values were higher in deep-litter hens than in those in conventional cages and free range.3. Phagocytic and chemotactic activities tended to rise in the deep-litter system, and oxidative burst was higher than in furnished cages. Cytotoxic T cells were decreased in furnished cages, both cytotoxic and helper T cells decreased in deep litter compared to free range.4. The IL-2 and IL-13 expression was higher in deep litter than in conventional cages, and IL-6 expression was higher in furnished cages than in free range.5. Housing system had no significant effects on the oxidative defence system; however, they affected heterophil functions, cellular defence mechanisms and cytokine production. The results suggested that breeders need to consider the housing system's potential effects on immune defence responses while applying a breeding strategy appropriate for animal welfare and consumer demand.

1. This study evaluated the effects of cyclic eggshell temperature between 10 and 14 d of embryogenesis on traits viz. the expression of MYOZ2, PPARγ and GPx7 in breast muscle, meat quality and incidence of white striping at slaughter age.2. Eggs were obtained from Cobb and Ross broiler breeders to investigate the response of breeds to eggshell temperature, which regulated air temperature. A total of 784 eggs were incubated at either the control eggshell temperature (37.8°C) from 0 to 18 d or exposed to cyclic high eggshell temperature (CHT) at 38.8°C for 6 h/d between 10 and 14 d of incubation. The temperature was 36.8°C between 18 and 21 d. Hatched chicks were reared under optimum rearing conditions. The birds were sampled at 19 d of incubation, at hatch and at 42 d post-hatch.3. There was no effect of eggshell temperature on yolk-free body weight and residual yolk sac weight. The CHT chicks had wider breasts on the day of hatching.4. At hatch and 42d post-hatch, PPARγ expression in Cobb-CHT was upregulated 4.78-fold and downregulated 3.28-fold, respectively, compared to the Cobb-control. At slaughter age, chickens from Ross-CHT had 1.98- and 2.33-fold upregulated PPARγ and GPX7 expressions, respectively, compared to Ross-control. The CHT increased GPx7 expression in the Cobb-CHT day-old chicks compared to the Cobb-control. On ED19, MYOZ2 expression was upregulated in Cobb and downregulated in Ross by CHT.5. The effects of breed and eggshell temperature on pH₁₅, L*, a*, expressible juice and cooking loss were not significant. The CHT increased the incidence of severe white striping lesions in Ross chickens.6. It was concluded eggshell temperature modulated embryo development, incidence of white striping and expression of related genes differently in the two commercial breeds.

1. Genetic improvement and widespread use of artificial selection may have impacted the genetic make-up of Indian chicken breeds. The genetic architecture of contemporary chicken population of India needs to be assessed for future improvement and conservation programmes. This study utilised whole-genome sequences in 180 chicken samples from 16 indigenous breeds, along with the Red Jungle Fowl and the commercial White Leghorn.2. A panel of 76 978 genome-wide single-nucleotide polymorphisms (SNP) was selected for comparative genome analysis after stringent screening. Breeds originating from the eastern regions of India exhibited higher genomic diversity, indicative of a rich repository of distinct germplasm. Conversely, the Uttara breed, from the northern hilly areas, display considerable genetic differentiation with diminished diversity compared to others, underscoring conservation concerns. The average coefficient (F_IS) of 0.084 caution the need to mitigate risks associated with inbreeding.3. The study revealed that the analysis of 76 978 genome-wide SNP will serve as a cornerstone in refining conservation strategies, to design interventions with greater precision.4. The contribution of Red Jungle Fowl to the gene pool of all native breeds was supported by this study. Genetic structuring indicated a relationship among breeds based on geographical proximity, underscored by varying levels of admixture.

1. Two experiments were conducted, the first was to investigate the effect of increasing digesta viscosity by dietary carboxymethyl cellulose (CMC) on the growth performance and intestinal morphology and characteristics of healthy birds. The second experiment evaluated the impact of increased digesta viscosity in birds during an Eimeria spp. challenge.2. In experiment 1, a corn-soybean meal-based basal diet was supplemented with 0, 10 or 20 g/kg CMC at the expense of cornstarch and offered to seven birds in each of eight replicate cages per diet from d 8 to 22 post hatching.3. Increasing digesta viscosity due to dietary CMC linearly reduced (p < 0.05) body weight (BW) gain and the apparent ileal digestibility of nutrients. The relative lengths of the duodenum, jejunum and ileum linearly increased (p < 0.01) with dietary CMC inclusion.4. In experiment 2, on d 14, 256 broiler chickens were randomly assigned to eight replicate cages in a 2 × 2 factorial arrangement of treatments with two CMC concentrations (0 or 10 g CMC/kg of diet), with or without an Eimeria challenge. On d 15, birds in the challenge groups were orally gavaged with a 1 ml solution containing 25,000, 25,000 or 125,000 oocysts of E. maxima, E. tenella and E. acervulina; or 1% PBS, respectively.5. Increasing digesta viscosity in Eimeria-challenged birds decreased the total tract digestibility of dry matter and gross energy (p < 0.05). The ileal gene expression of glucose transporters was upregulated (p < 0.05) in challenged birds that received the CMC-supplemented diet.6. In summary, increased digesta viscosity induced changes in the expression of nutrient transporter genes and decreased nutrient utilisation in Eimeria-challenged birds.

1. The purpose of this meta-analysis was to evaluate the effect of mannan oligosaccharide (MOS) as an alternative to antibiotic growth promoters (AGP) on feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) of broilers.2. Data from 75,594 broilers were extracted from 17 articles (19 trials) published between January 2010 and March 2023. The main criteria for the publication selection were as follows, at least three treatments applied (negative control group without MOS or AGP versus MOS or AGP supplementation), presence of performance results, and intra-experimental variation associated with the mean of response (such as standard error). Treatments were classified as control, MOS, or AGP, and adjusted means of treatment were compared. Additionally, the average daily gain (ADG) and average daily feed intake (ADFI) of each type of supplementation were calculated relative (Δ) to the control group (ΔADFI and ΔADG) and expressed as a percentage of the difference.3. Broilers receiving a diet supplemented with MOS had a 3.7% better BWG and 3% better FCR compared to the control diet (P < 0.001), but these variables were similar to the group receiving AGP supplementation. No significant difference was detected in FI among treatments (P > 0.050). The relationship between ΔADG and ΔADFI was linear for the MOS and AGP-supplemented group (P < 0.050). The ΔADG of broilers fed diets supplemented with MOS or AGP was 6.4% and 4.54% when ΔADFI was zero, respectively. The ΔADG of MOS increased by 0.58% for every 1% of increasing observed in ΔADFI. The corresponding value for the increased ΔADG for the AGP group was 0.69%.4. The results of this meta-analysis indicated that MOS supplementation is effective in increasing BWG and reducing FCR, similar to broilers fed a diet supplemented with AGP. Therefore, MOS is a safe and sustainable alternative for AGP-free poultry production.

1. The objective of the present study was to examine the effect of lighting programs and light colour on ocular health variables as welfare indicators in Ross 308 broilers.2. A total of 384, male, one-d-old broiler chickens (Ross 308) were placed in a completely randomised design with a 2 × 2 factorial arrangement of lighting program (continuous or intermittent) and light colour (white and green LED light). Ross 308 broilers under restricted lighting had 18 h of light (18 L:6D), while those under intermittent lighting had cycles of 17 L:3D:1 L:3D throughout the experimental period, which lasted 42 d.3. At the end of the experiment, all eyes of birds (n = 96 birds) underwent a complete ophthalmic examination, which included the Schirmer tear test I, intraocular pressure and eye dimensions. In addition, 32 broilers (eight birds per trial groups) aged 42 d underwent ophthalmic examination to include assessment of ocular ultrasound biometry.4. Light colour had a significant influence on the mean intraocular pressure (p < 0.001). The Ross 308 broilers kept with intermittent lighting had lower eye weights (2.29 g; p < 0.05), palpebral fissure length (14.39 mm; p < 0.01), eye dorsoventral diameter (17.46 mm; p < 0.05), anteroposterior size (13.70 mm; p < 0.01) and corneal dorsoventral diameter (7.81 mm; p < 0.05) compared to those reared under restricted lighting.5. In conclusion, these values for Ross 308 broilers may be applied in poultry ophthalmology to detect early eye disease symptoms and to help the diagnosis of tear disorders that could cause economic losses and welfare issues. Intermittent lighting and green LED light may help reduce eye health problems thus contributing to improved welfare in broilers.

1. It was assumed that the concentrations of arsenic (As), chromium (Cr), cobalt (Co), lead (Pb), manganese (Mn) and mercury (Hg) in the meat, kidney and liver of cattle, broilers and goats within Quetta city potentially exceeded the permissible limits for heavy metal content. Risk assessment of these heavy metals on human health were estimated based on daily intake (EDI), target hazard quotient (THQ) and hazard index (HI).2. Samples of the meat, liver and kidney of cattle, broilers and goats were collected from butcher shops and slaughterhouses in 20 different areas of Quetta city. Overall, 180 samples were analysed, each for six heavy metals. After acid digestion of meat samples, heavy metals analysis was carried out via atomic absorption spectroscopy.3. The results varied in levels depending upon the species and organ type. The average concentrations of As, Pb and Hg were within the established reference limits of the Australia New Zealand Food Authority (ANZFA 2015) and the European Commission (EC, 2006), although some samples exceeded these limits. Compared with the kidney and meat, the liver was the primary tissue for Cr, Pb and Hg bioaccumulation. Metals concentration were mostly within the normal range in samples from cattle and goats, while the Mn concentration was elevated in broilers.4. The estimated daily intake (EDI) revealed that the intake of As, Co, Pb and Hg was mainly derived from goat and cattle products, whereas broiler samples were more contaminated with Cr and Mn. The EDIs of Cr and Hg in adults exceeded the oral reference dose, referring to potential adverse effects. The EDIs for Co and Mn were low, suggesting that additional intake sources were necessary. Except for As, none of the determined elements had a target hazard quotient (THQ) above 1.

1. The extensive use of antimicrobials in poultry production may contribute to the emergence of resistant bacteria. This study was conducted to determine the prevalence and resistance of different E. coli strains isolated from raw chicken meat and to investigate the possibility to use Lebanese native oregano essential oils as alternatives.2. In total, 250 chickens from Lebanese markets were examined for the presence of E. coli. Isolates were then screened for susceptibility using 19 antibiotics and two essential oils extracted from oregano plants.3. Of the 250 chickens tested, 80% were contaminated with E. coli. Main resistance was seen against amoxycillin, ampicillin, penicillin, tetracycline, tylosin, streptomycin and erythromycin. The highest rate of sensitivity was found in 86.1% of strains to Amoxycillin/Clavulanic acid, 80.09% to Tilmicosin. Both essential oils from Origanum syriacum (98%) and O. ehrenbergii (97.3%) showed promising potential in inhibiting the growth of the tested bacteria. Oil from O. syriacum exhibited superior efficacy against 200 E. coli strains, inhibiting 46.1% at 200 mg/l and all at 400 mg/l, while O. ehrenbergii oil showed slightly lower inhibition, affecting 41.6% at 200 mg/l and all at 400 mg/l.

1. A stimbiotic (STB) is any feed additive that stimulates caeca fibre fermentation, although the additive itself contributes little to the caeca short-chain fatty acid (SCFA) production. A 42 d experiment investigated the interactive effects of STB and wheat bran (WB) in broiler chickens receiving maize or wheat-based diets.2. The treatments were arranged in a 2 × 2 × 2 factorial (eight replicates each), the dietary factors being diet (maize-SBM or wheat-SBM), STB (with or without) and WB (0 or 50 g/kg). Jejunal tissue, gizzard, jejunal and ileal digesta and caecal contents were collected on d 18 and 42.3. Gizzard pH tended to decrease with STB (p = 0.06) supplementation and was lower in birds fed wheat- compared to maize-based diets on d 18 (p < 0.05). Birds receiving diets with WB had higher jejunum pH on d 18 (p < 0.05).4. Total short-chain fatty acids (SCFA) in the caeca on d 18 and isobutyrate on d 42 were higher (p < 0.05) for maize compared with wheat-based diets. However, on d 42, acetate, butyrate and total SCFA were higher (p < 0.05) for wheat-based compared with maize-based diets.5. On d 18, STB and WB inclusion increased villi height (VH; p < 0.05) and VH to crypt depth ratio (VH/CD), respectively (p < 0.05). On d 42, VH (p < 0.05) and VH/CD were higher in wheat-based diets (p < 0.05). The VH/CD ratio was lower with STB supplementation (p < 0.05). Marker-corrected pentose oligosaccharides (Pent)₄ and (Pent)₅ concentrations in the ileal digesta were reduced (p < 0.05) with STB supplementation. In addition, STB decreased (Pent)₃ concentration in maize-, but not wheat-based diets (p < 0.05).6. In conclusion, both WB and STB influenced gastrointestinal pH and jejunum histomorphology of broilers without increasing oligosaccharide concentration in the ileum and SCFA in the caeca.

1. Male and female Chukar partridges are difficult to differentiate based on their morphology or by the Chromobox-Helicase-DNA binding (CHD) during early growth.2. The current study developed a novel, simple, low-cost and rapid sexing protocol for Chukar partridges based on the newly defined sexing gene ubiquitin-associated protein 2 (UBAP2).3. The length of polymorphism between UBAP2-W and UBAP2-Z homologous genes allows for easy sex discrimination in this species. Molecular sexing analysis was based on the simultaneous amplification of both genes, resulting in two distinct amplicons (947 bp and 535 bp) in heterogametic females and only a single band (535 bp) in homogametic males, which is easy to detect with agarose gel electrophoresis.4. This technique is simple and convenient for genetic sex determination in Chukar partridges.