ABSTRACT 1. Chicken erythrocytes in blood vessels are the most abundant circulating cells, which participate in the host’s immune responses. The transcription factor nuclear factor-kappa B (NF-κB) plays a vital role in the inflammatory response following viral infections. However, the expression of the NF-κB pathway, and other immune-related genes in chicken erythrocytes infected with low pathogenic avian influenza virus (LPAIV H9N2), has not been extensively studied. 2. The following study determined the interaction of LPAIV H9N2 with chicken erythrocytes using indirect immunofluorescence microscopy. This was followed by investigating myeloid differentiation primary response 88 (MyD88), C-C motif chemokine ligand 5 (CCL5), melanoma differentiation-associated protein 5 (MDA5), the inhibitor of nuclear factor-kappa B kinase subunit epsilon (IKBKE), NF-κB inhibitor alpha (NFKBIA), NF-κB inhibitor epsilon (NFKBIE), interferon-alpha (IFN-α), colony-stimulating factor 3 (CSF3) and tumour necrosis factor receptor-associated factor 6 (TRAF6) by mRNA expression using quantitative real-time PCR (qRT-PCR) at four different time intervals (0, 2, 6 and 10 h). 3. There was a significant interaction between erythrocytes and LPAIV H9N2 virus. Furthermore, the mRNA expression of the NF-κB pathway and other immune-related genes were significantly up-regulated at 2 h post-infection in infected chicken erythrocytes, except for TRAF6, which were significantly downregulated. While at 0 h post-infection, IFN-α and CSF3 were significantly upregulated, whereas NFKBIA was significantly downregulated. Further expression of MDA5, CCL5 and NFKBIA was upregulated, while TRAF6 was downregulated at 6 h post-infection. In infected erythrocytes, expression of MyD88, CCL5 and IKBKE was upregulated. However, IFN-α and TRAF6 were downregulated at 10 h post-infection. 4. These results give initial evidence that the NF-κB pathway, and other genes related to immunity, in chicken erythrocytes may contribute to LPAIV subtype H9N2 and induce host immune responses.

ABSTRACT 1. Stocking density is an issue for poultry production. High stocking density can impact biochemical parameters, production, and reproductive performance; however, information regarding the effects of stocking density on serum metabolites in geese is limited. 2. Twenty-day-old, Sanhua male geese (n = 240) were allocated to one of two experimental groups for 50 days. One group was housed under a low stocking density (LSD; two birds per m2) and one under a high stocking density (HSD; five birds per m2). Body weight and feed intake were recorded every 10 d. Eight serum samples per group were used for metabonomic analysis by liquid chromatography-mass spectrometry. 3. Stocking density did not affect the spleen, liver, thymus, or bursa of Fabricius weights after 50 d. Feed intake and body weight was significantly lower in geese from the HSD group versus the LSD group (P < 0.05). Thirty-six differential serum metabolites were identified (P < 0.05), indicating altered amino acid, carbohydrate, lipid and vitamin cofactor metabolism. 4. The results demonstrated that high-density stocking impacts geese, and provides insights into the mechanisms underlying the adverse health effects associated with HSD.

ABSTRACT 1. The long noncoding RNA lncGLM is significantly differentially expressed in the livers of peak-laying hens compared with that in the livers of pre-laying hens, but its potential biological role and expression regulation are unclear. 2. To explore the potential biological function of lncGLM, single nucleotide polymorphism (SNP) detection and association analysis were carried out in the Gushi×Anka F2 resource population. 3. The tissues and spatiotemporal expression characteristics of lncGLM were analysed by real-time quantitative PCR. The effects of 17β-oestradiol on the expression of lncGLM expression were analysed through in vitro and in vivo experiments. 4. The results showed that a g.19069338 T > C SNP was present in lncGLM. Association analysis revealed that lncGLM was significantly associated with body slanting length at 12 weeks, body weight at 12 weeks, shank length at four weeks, chest depth at eight weeks, pelvic width at 12 weeks, eviscerated weight, head weight, pancreas weight, pectoralis weight, leg muscle weight, muscular stomach weight rate, pancreas weight rate, carcase weight, aspartate aminotransferase, creatinine and pectoral muscle water loss rate. 5. The expression of lncGLM in the liver was higher than that in other sampled tissues. In addition, the expression of lncGLM in the liver was significantly higher in the peak-laying period than at the pre-laying period. Both in vitro and in vivo experiments showed that lncGLM expression was regulated by 17β-oestradiol via oestrogen receptor alpha (ER-α). These results demonstrated that the chicken lncGLM gene is highly expressed in liver tissue and regulated by oestrogen through ER-α.

ABSTRACT 1. The purpose of the present study was to examine whether zymosan, which is a component of fungi, affects feed passage through the digestive tract in chicks (Gallus gallus). 2. Intraperitoneal (IP) injection of 2.5 mg zymosan significantly reduced the crop-emptying rate and this effect was similar to that of 100 µg lipopolysaccharide (LPS). Zymosan affected phenol red transit from the proventriculus. 3. Zymosan significantly affected the gene expression of interleukin-1β (IL-1β), IL-6, IL-8 and histidine decarboxylase in various regions of the digestive tract. 4. The present study suggested that zymosan retarded feed passage through the digestive tract in chick and interleukins and histamine may be participating in this process.

ABSTRACT 1. Pulmonary hypertension, associated with mitochondrial function in the lung tissue of broilers, can occur at hypoxic high altitudes. The present research examined the impacts of O2 supplementation at different embryonic stages on broiler organ development and antioxidant enzyme activities. 2. In total, 360 eggs from Ross 308 broiler breeders at sea level were divided into a control group (O2 non-supplementation group) and three experimental groups daily 1 h 23.5% O2 supplementation from days 0 to 11 (O0-11), from days 12 to 21 (O12-21), and from days 18 to 21 (O18-21) of embryonic age. 3. The lung, heart, right ventricular (RV), and left ventricular (LV) + septum of newly hatched and seven day old chicks from every group were dissected and weighed. Antioxidant enzyme activities were examined in their lung tissue. 4. The lung weight did not change in any group. At hatching, the heart weight (g and %) was higher in the O12-21 and O18-21 groups than in the O0-11 and control groups, but the relative heart weight was the highest in the O18-21 group in comparison with the O12-21 group. 5. Superoxide dismutase (SOD) activity increased in all experimental groups at both ages, but glutathione peroxidase (GPx) activity increased only in seven day old chicks. Catalase (CAT) exhibited high activity in the O12-21 and O18-21 groups at hatching. In the seven day old chicks, while the CAT activity did not change in the O18-21 group, it decreased in the O0-11 group and increased in the O12-21 group. 6. Glutathione reductase (GR) activity did not change in the O18-21 group, but GR exhibited low activity in the O0-11 group and high activity in the O18-21 group in newly hatched chicks. The GR activity only decreased in the O18-21 group of seven day old chicks. 7. The results indicated that oxygen supplementation to the incubator caused alterations in the antioxidant enzyme activities in the lungs of broiler chicks, and this may have been in response to oxidative stress.

ABSTRACT 1. Two experiments were carried out to investigate the influence of substitution levels, assay methods and adaptation length of broilers to experimental diets on metabolisable energy of corn and barley (Experiment 1) and soya bean meal (Experiment 2). In each experiment, the test feedstuffs proportionately replaced the reference diet at the rates of 150, 300 or 450 g/kg. Each treatment had 8 or 7 replicate cages containing three birds per cage. Broiler chickens were adapted to experimental diets for either 7 or 4 d prior to excreta collection on d 20 and 21. 2. Metabolisable energy was determined using the difference method at each substitution level and the regression method, using the 4 combinations of the substitution levels. 3. In Experiment 1, AME and AMEn were lower (P < 0.01) for barley than for maize, irrespective of the assay method and there was a trend for an adaptation × cereal grains interaction (P < 0.10) for AME determined by the difference regression method. For maize, AME and AMEn calculated using regression or the difference method were not significantly different, whereas barley AME and AMEn values were greater (P < 0.01) when derived using regression analysis. 4. In Experiment 2, there was no significant adaptation length × substitution levels interaction. The AME and AMEn values were lowest (P < 0.01) at 150 g/kg SBM inclusion level when calculated using the difference method. On the other hand, AME and AMEn values determined by the regression method were not influenced by substitution levels. 5. It was concluded that the influence of substitution levels on assayed metabolisable energy is feedstuff-dependent and that the regression method produced more consistent metabolisable energy values in a feedstuff-independent manner.

ABSTRACT 1. Innate immunity provides the first line of defence against pathogenic organisms through a myriad of germline encoded receptors called pattern-recognition receptors (PRRs). Toll-like receptor (TLR) 3, as an important member of PRRs, is indispensable for host defence against viral infection by recognising virus-derived RNAs. However, little is known about the structure and function of TLR3 in ducks (Anas platyrhynchos), a natural host for the avian influenza virus. 2. This study cloned the full-length cDNA of duck TLR3 using reverse transcription polymerase chain reaction (RT-PCR) with rapid amplification of cDNA ends (RACE). The cDNA sequence of duck TLR3 was 4046 bp in length and encoded 895 amino acids. Multiple sequence alignment showed that duck TLR3 shared high similarity with that from other vertebrates. 3. Quantitative real-time PCR (qRT-PCR) analysis suggested that TLR3 mRNA was constitutively expressed in all tissues tested, having higher levels in the kidney, liver, breast muscle, ovary and heart. After stimulation with viral- or bacterial-mimics, including LPS, poly(I:C), pam3CSK4, FLS-1, FLA-ST and R848, the TLR3 transcript was significantly upregulated. Meanwhile, overexpression of duck TLR3 significantly promoted the transcription of IFN-β, IRF7, TRIF, Mx, STAT1 and STAT2 mRNA after stimulation with poly(I:C). 4. These results suggested that TLR3 play an important role in resistance against viral and bacterial infections in ducks.

ABSTRACT 1. The additivity of apparent ileal digestibility (AID) and standardised ileal digestibility (SID) of phosphorus (P) in mixed diets containing corn and canola meal (CCM) with or without phytase supplementation and the impact of age on the basal ileal endogenous loss (BEL) of P were investigated in broiler chickens. 2. Treatments were arranged as a 2 × 3 × 2 factorial with two ages (13 d or 21 d post hatching), three diets (corn, canola meal, or CCM), and two phytase levels (0 or 1,000 FYT/kg diet) in a randomised complete block design. There were eight or six birds per cage at 13 d and 21 d of age, respectively, and six replicate cages per treatment, with a total of 588 birds. A P-free diet (PFD) treatment was included at each age to determine the basal endogenous loss (BEL) of P. 3. Birds were fed a commercial starter diet from d 1 to d 10 or d 18 and then fed the experimental diets for 3 d until d 13 or d 21, respectively. Predicted digestibility values calculated from the individual feed ingredients were used to test additivity in the mixed diets. Chromium oxide was included in diets as an indigestible marker. 4. The ileal digesta, collected from birds at d 13 or d 21, was used to determine nutrient digestibility. 5. The AID and SID of P at d 13 was higher (P < 0.01) when compared with older birds at d 21, regardless of dietary phytase supplementation. Regardless of age or phytase supplementation, AID and SID of P were additive, as there were no differences between predicted and determined values in the mixed diets. The BEL of P (g/kg DM intake) in birds at d 13 was higher (P < 0.05) than birds at d 21 (0.197 vs. 0.159). 6. In conclusion, age had an impact on the BEL of P and the utilisation of minerals in the diets. The apparent and standardised ileal digestibility of P in the mixed diet containing corn and canola meal were additive, regardless of age or phytase supplementation.

ABSTRACT 1. When geese or ducks are overfed with a high-energy diet rich in carbohydrates, their liver increases in size by 5- to 10-fold in 2 weeks, which is accompanied by the occurrence of hepatic steatosis. As a result, this distinctive genetic characteristic of waterfowl has been taken advantage of to produce foie gras. 2. When overfed geese were fed a regular diet for a 20-d period of recovery, their liver was restored to the original state. Hence, the entire process is reversible, and cause no lasting cirrhosis or necrosis in the liver. This suggests that waterfowl have a mechanism to protect their liver from the harm caused by severe hepatic steatosis. 3. This paper reviews the formation, physiological changes to metabolic pathways and the protective mechanisms in geese and ducks with hepatic steatosis. Not only will understanding these mechanisms provide ideas for the waterfowl breeding selection for foie gras, it is conducive to improving production efficiency and quality of foie gras. This provides a scientific basis to ensure animal welfare and an approach to the prevention and treatment of fatty liver disease in human.

ABSTRACT 1. Salmonellosis is one of the most important diseases in public health and it is usually associated with poultry product consumption. This study aimed to validate rapid methods to detect Salmonella spp. from poultry samples. 2. A DNA isothermal amplification method, previously developed for other matrices, was applied for the specific detection of Salmonella spp. from various samples, including poultry tissues, drag and boot swabs, faeces and feed. A new procedure was validated with Salmonella spp. serotypes and isolates from other enteric bacterial species, as well as naturally contaminated poultry samples. 3. The study demonstrated the successful development and implementation of a procedure, including a DNA isothermal amplification method, for the detection of Salmonella spp. directly from tissues, drag and boot swabs, faeces and feed. The whole procedure can be performed in less than 24 hours and it has been successfully used in a veterinary diagnostic laboratory.