We have just had our impact factor in for 2018 and we are slightly down by 5% at 1.364 (2017 was 1.439) but still very strong, considering we are only a small journal and take review, not experimental, papers. This issue is slightly shorter, due to the timelines involved in handing over to a new publisher at the end of the year, so apologies for that, but we still have a good spread of papers relating to immunity, water quality, minerals, slow growing breeds, genetic conservation, welfare and techniques in poultry production. Thanks to the efforts of all those involved with the journal, especially the Editorial Committee, for keeping things moving along in accordance with the tight deadlines in this year of big changes. Thanks also to the publishers, old and new, for providing all the information needed for the handover to date.

One issue we do have, and I would ask for authors forbearance on this, is that we are seeing a major slowdown in getting reviewers to commit to papers and getting them back in on time. We do actively chase up reviewers every week, but sometimes we are having to invite eight or more to get the required reviews in. Please can authors help out here by suggesting good reviewers on submission, and, perhaps, already have these secured as agreeable and available to review. This isn’t something specific to our journal – it is a growing trend, with many reviewers being increasingly busy in their day to day work. I would like to thank all our reviewers who give up their time, unpaid, to keep the journal on track.

As I am writing this, we are getting ready for our annual board meeting in Montreal, Canada, which is at the end of the PSA conference. I am hoping to catch up with many readers, authors and reviewers there. 2019 sees many good conferences, and I do hope you will all try to attend some of these. In addition, the next WPC is going to be upon us soon, in Paris in August 2020. It looks to be a great event, and the French branch have been working very hard to organise this – so get your papers in and come along. Please note that I, and other members of the board, will be on the lookout for papers suitable for the journal at conferences and seminars, and you may find yourself invited to submit. Otherwise, I trust all our readers have a good summer and hope to see you at an event.

Dr Lucy Waldron

Editor

Arsenic (As) is highly toxic element, even at very low concentrations in feed and drinking water. Its physiological role in poultry is well established, as it is essential for the synthesis of methionine metabolites including cysteine, even though it is a teratogenic and carcinogenic element. Paradoxically, recent studies have uncovered its nutritional value. The recommended amounts of As in poultry feed are between 0.012 and 0.050 mg/kg. Water is the primary route for the transfer of As and exposure of animals to its toxic effects. The available data on the impact of water contamination on the deposition of As in broiler tissues are rather scarce. The amount of As was 0.006-0.015 mg/kg in breast meat, 0.007-0.017 mg/kg in drumstick meat, 0.001-0.014 mg/kg in liver and 0.008-0.016 mg/kg in testicles of broilers at the end of a 42 day experiment after exposure to naturally contaminated drinking water. The toxic dose of As for poultry is between 40 and 50 mg/kg of poultry feed whereas the amount of 40 mg/kg leads to decreased egg production and the amount of 50 mg/kg leads to decreased feed consumption. Symptoms of chronic As exposure differ among individuals, populations and geographic regions, which suggests that there is no universal definition of symptoms associated with chronic As poisoning. Moreover, some individuals can tolerate high As, that is, levels that can be fatal for others. In wild birds, the content of As was the highest in meat of march hens (0.063 mg/kg), seagull muscle tissue (0.058 mg/kg), in meat from swans (0.022 mg/kg) and the white-tailed eagle (0.022 mg/kg). In this review, the essential role and toxicity of As in poultry nutrition is addressed with particular emphasis on its importance as a contaminant of poultry feed and products.

Conservation of animal genetic resources is considered as one of the main challenges of today's breeding. Every breed of livestock is a valuable element of the world's animal genetic diversity. Over the last few decades, considerable reductions in the number of local breeds and their sizes have been registered. This trend caused the need to implement conservation programmes for endangered goose species. Poland has a number of local goose breeds which are the achievements of many generations of breeders. The objective of this review was to present the current status of the realised conservation programmes for 14 goose breeds in Poland by analysing population and molecular parameters. The conservation status of these populations has been presented including the effective population sizes, hypothetical inbreeding level, trends in performance traits as well as parameters estimated on the basis of genetic markers. In all the cases population sizes were well over 100 individuals, which is the minimum recommended by the FAO for conservation flocks. The effective population size ranged from 179 to 452, affecting a relatively low inbreeding level from 0.1 to 0.74%. The estimated correlations between hypothetical inbreeding rates and reproduction traits were negative. The heterozygosity coefficients varied from 0.27 (Biłgorajska breed) to 0.55 (Garbonosa breed). Generally, the parameters for goose breeds in Poland were compatible with the recommendations of the FAO.

Artificial intelligence (AI) already represents a factor for increasing efficiency and productivity in many sectors, and there is a need for expanding its implementation in animal science. There is a growing demand for the development and use of smart devices at the farm level, which would generate enough data, which increases the potential for AI using machine learning algorithms and real-time analysis. Machine learning (ML) is a category of algorithm that allows software to become accurate in predicting outcomes without being explicitly programmed. The essential principle of machine learning is to construct algorithms that can receive input data and use statistical analysis to predict an output. Exploitation of machine learning approaches, by using different training inputs, derived the prediction accuracy of growth and body weight in broiler chickens that ranged from 98 to 99%. Furthermore, a neural network with an accuracy of 100% identified the presence or absence of ascites in broiler chickens, while the support vector machine (SVM) model obtained an accuracy rate of 99.5% in combination with machine vision for the recognition of healthy and bird flu-challenged chickens. Consequently, machine learning algorithms, besides accurate growth prediction of broiler chickens, can successfully contribute to health disorders prediction. It is obvious that machine learning has a great potential for application in the future. This paper analyses machine learning applications in broiler growth and health prediction, and its ability to cope with high inputs of data and non-linearity can successfully replace common methodology.

Water makes up over 98% of all molecules in the body and it is necessary for several biological processes. Water quality has been shown to influence animal's performance. In recent years, interest in water treatment technology has increased, particularly in poultry. Magnetised water is one of water treatment that has attracted poultry researchers and breeders, due to its low cost compared to chemical and physical water treatments. Water magnetisation changes water properties, making it become more fluid, alkaline and energised. Unfortunately, the information detailed in the literature provides opposite views on the effect of magnetised water on poultry's performance. However, magnetised water, particularly with high gauss (more than 1000 gauss/month) could improve health (immunity), growth (approximately +4 % in weight) for broilers and enhance some egg production traits for hens, such as eggshell thickness (approximately +9 %). This review provides information detailed in the existing literature on the influence of magnetised water on poultry health and production.

In the face of reducing reliance on in-feed antibiotics, a greater emphasis has been placed on the development of vaccines. Adjuvants play important role in vaccine refinement. Apart from conventional adjuvants, others, like cytokines and toll-like receptors (TLR), have been evaluated experimentally. For example, Pam3CSK4, Polyinosinic-polycytidylic acid are used as immunostimulatory agents which upregulate the expression of type 1 IFNs against avian influenza. The use of TLR4 (lipopolysaccharide; LPS), TLR7 (Loxoribine) and TLR21 (CpG-ODN) agonists have shown good results when used as adjuvants with the avian influenza vaccine. The LPS (TLR4) was used as an adjuvant and liposome as intranasal antigen delivery system for Newcastle's disease (NDV) antigen, which induced significant increases in secretory IgA in tracheal lavage fluid and serum IgG levels. In a challenge study it provided 80% protection against virulent challenge. When resiquimod (TLR7) was used as an adjuvant with inactivated NDV, this potentiated the protective response to 100% against virulent NDV challenge, while protection was only 80% in the vaccine alone group. When 64CpG-plasmids (TLR21) were co-administered with inactivated AIV H5N2 vaccine in chickens, it led to a higher HI titre at two and four weeks of age, and provided 100% protection against virulent challenge of avian influenza. The TLR 3 agonist (poly I:C) showed good results against NDV and avian reovirus. Other TLR agonists and cytokines used against NDV include LPS, loxoribine, CpG-ODN and ChIFN-α, IFN- γ (with an in ovo vaccine). Immunostimulatory adjuvants like LPS, chicken TLR21, have been tried with Marek's disease vaccine, and TLR 5 agonist was used against Salmonella enteritidis and Eimeria tenella. Although the study of cytokines and TLRs in avian species is still in its infancy when compared to that of mammals, huge strides have been made in recent years. In this article, recent studies involving the assessment of immunostimulatory adjuvants in poultry are reviewed.

Slow-growing, male chickens raised with outdoor access have been found to be a nutritious protein source with 24.83% protein in breast muscle. They have an acceptable carcass quality with at least 20% less abdominal fat, 3% more breast yield, and 3% more thigh yield than the birds raised in confinement. Similarly, slow-growing male chickens grown with outdoor access have a good bone quality with femur weight, length and diameter (16.5 g, 96.7 mm, and 8.61 mm, respectively). Considering fatty acid profile as a meat quality trait, breast muscles of slow-growing birds grown with outdoor access compared to those without such access have significantly higher polyunsaturated fatty acids level (3.85 vs. 3.36%), lower n6:n3 PUFA ratio (7.8 vs. 9.22) and lower saturated fatty acids content (26.29 vs. 28.73%). Raising slow-growing male chickens in production systems with outdoor access has been confirmed to be beneficial for the animals, the producers, the consumers and the environment.

In evaluating the quality of table eggs and the developmental stages of embryonic eggs, spectroscopic techniques provide greater efficiency than traditional, time-consuming and laborious approaches. This review summarises recent developments in the spectroscopic analysis of table eggs, including the determination of the chemical composition (ratios of performance to standard deviation of 4.38, 2.25, 2.28, 2.31, and 3.03 for fat, moisture, and protein in egg yolk and moisture and protein in egg albumen, respectively, have been reported). A Haugh unit detection accuracy RMSEP (root mean square error of prediction) for quality of 6.29 was obtained by hyperspectral imaging) for table eggs and fertility detection (for white-shell eggs, fertility detection has been realised at a promising rate of 93.5%) and gender determination in hatching eggs. In conclusion, hyperspectral imaging generally outperforms visible or near-infrared reflectance spectroscopy when evaluating both consumption eggs and hatching eggs, and near-infrared reflectance Raman and fluorescence spectroscopy exhibit a strong potential for gender determination prior to hatching. Scientists have attained a correct sexing rate above 90% at 3.5 d of egg incubation without removing the inner shell membrane. In the detection of blood-spot eggs or fertile eggs, eggshell colour proved to be a negative factor.

Stress can exert modulatory effects on pain perception in animals, as exposure to a stressor can result in either the reduction or amplification of the perceived severity of pain. These phenomena are widely described as stress-induced analgesia (SIA) and stress-induced hyperalgesia (SIH). The two are mediated by the same underlying mechanisms, but occur due to different stressors and different responses from the pain pathway. SIA and SIH have been demonstrated with a variety of stress and pain stimuli in rodents, humans and other mammals. There is some evidence that SIA occurs in birds and that they have the neurological systems and brain regions necessary for SIH. Tonic immobility (TI) is related to SIA in mammals, and there is evidence the avian brain is compatible with TI having analgesic effect, but it could have a hyperalgesic effect. This review looks at the mechanisms and evidence of SIA, SIH and TI in mammals and discusses evidence relating to the occurrence of these phenomena in birds.

The World’s Poultry Science Journal is indebted to Prof J.A. Castello, Prof D.K. Flock, Dr M. Tixier-Boichard, Dr S. Cherepanov and Dr Jiangxia Zheng for the translations of these summaries.