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

The second issue of the 2019 volume has already come around, and it has been a busy year to date, with many publishing changes occurring with the move of the WPSJ from Cambridge University Press to Taylor and Francis, our new publishing house. Thanks to all staff and to the WPSJ Editorial Committee, Drs. Bob Buresh, Werner Bessei and Zehava Uni, as well as other WPSA and publisher staff for their help with these changes. An official announcement for members is now being prepared.

The conference season is already upon us, with meetings being reported from Asia as well as Europe in this issues Association News. I have recently attended the UK WPSA meetings, held jointly with the British Society of Animal Science in Edinburgh in April. At the WPSA meeting, Dr. Emily Burton announced the new Gordon Rosen Award which is aimed at providing grant money for people either in or recently completed their PhD programme who wish to travel to work for short periods in other institutes away from their home country. This can be to increase knowledge of certain techniques or increase their understanding of what they can do within the world of poultry science. Sadly, Gordon died a couple of years ago, and is fondly remembered not only for his wit and intelligence, but also his generosity to the WPSA over many years where he supported membership for students. Many thanks must go to the generosity of Mrs. Vanda Rosen for making this award, as well as to Dr. Mike Bedford, who has been on the trustees board with myself to get this off the ground, and Dr. Dawn Scholey for her input during the meeting.

In this current issue, readers can find reviews on microalgae, nutraceuticals, yeast, fertility, genetics and nutrition, as well as welfare in terms of injuries caused by housing systems. We are experiencing a good number of submissions on antibiotic alternatives – and authors need to note that these must be very specific and focussed tightly on certain aspects in detail, rather than general reviews, as this topic is very popular around the world currently, and requires in-depth reviewing. This is due to the increasing limitations on AGP use in feed in various countries, such as China and the USA. So, we in the editorial office expect more on alternatives to keep coming in. As a result, we are always encouraging reviews in other topics to keep the WPSJ as balanced as we are able for our readership.

Dr Lucy Waldron

Editor

Welcome to the first issue of 2019 – I trust all our members enjoyed the holiday period and had a happy new year. This issue covers a range of topics, including genetics, meat processing, novel feed ingredients, immunity, behaviour and management systems. Currently, myself and the newly appointed editorial team from the Global Board are working hard to make some changes to the journal, not least the hand over to a new publisher (Taylor and Francis) from the current publisher (Cambridge University Press). I would like to thank both of these publishers for their help and support during the transition period. Authors and readers will hopefully not notice any difference in their interaction with the journal, as I aim to have a seamless handover.

The year 2019 sees many excellent WPSA events being planned. There are 19 events currently listed on the www.wpsa.com website giving details and links to conferences and meetings. Please take a look at what is on offer, and attend where possible. Our association news covers some very interesting topics – including an initiative from Pakistan to encourage more women into poultry science. I would like to congratulate the branch on this – and please let me know if you want some input from your female journal editor – happy to help and show young women in agriculture what opportunities are out there and how you can make a difference.

We have lost some notable poultry scientists in the last 12 months – most recently Jim McNab who sadly died suddenly over the Christmas holidays at home. Jim was a mentor to me many years ago when I was a PhD student and spent a week working with him learning how to conduct TME trials. He remained a friend and colleague from that time. Jim, of course, was the WPSJ Editor in the 1990s and an active WPSA member, organising various poultry events over the years. Our thoughts are with his wife Carol and the family.

As ever, I trust you all enjoy this issue of the WPSJ.

Dr Lucy Waldron

Editor

Well it’s been a busy time for us here recently at WPSJ, and the handover has now been made from Cambridge University Press (CUP) to Taylor and Francis (T&F). This is the last issue published by CUP, as the March issue will be assembled by T&F. I would like to thank all concerned, especially Dan Edwards and Richard Horley (CUP), Jennifer Stokes and her team (T&F) as well as Dr Shay Rutherford for keeping the papers moving whilst I was busy organising the handover, as well as Dorien Kleverwal in the Dutch office for helping organise the new workflows. Hence this is the last issue that will be produced by CUP. I would like to thank all their team, past and present, for their friendly, helpful work over the years, especially when we have needed fast responses to problems with publishing. The changeover has allowed new mechanisms regarding the journal to be put into place, including a new, and active section editor team in the form of the new Editorial Board, which will take a lot of workload off my shoulders. There will be more automation regarding submission of papers – so authors should expect emails regarding initial formatting and so on to come from T&F during pre-screening.

This issue contains the first retraction of a paper that I have presided over in my editorship. This is an important legal issue – and thanks to Rosemary Dickin for her expertise in publishing ethics (COPE) at CUP in ensuring the proper procedures were adhered to at all time. As editor, I had to ensure all the COPE guidelines were followed regarding checking reviewer’s comments and that all had been done properly at the editing end. Standard procedures had to be followed, regarding letters to and from authors and the complainant. However, as the author did not submit an official letter in response, in the required format, we have had to make a decision at the editorial level.

It may seem obvious to state, but as authors or reviewers, you must be aware that your comments and papers are open to public and commercial scrutiny. At WPSJ we have a system involving standard peer review, but we do rely on our reviewers to read papers fully and ensure there are no highly selective, conflicting or erroneous statements being made.

It only remains for me to send all our readers greeting for the holidays, and thanks to all our readers, reviewers, new editorial board members and authors for another year of support for the Journal.

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.

Today's broiler is characterised by faster-, leaner-growth. A large part of this progress is attributed to the genetic selection that had, and continues to improve growth rate and composition of gain at steady pace. As an illustration of such increases in performance, 2.3 kg live gain (slaughter weight) has been reduced from requiring 52 days in 1995 to 36 days in 2017 - a reduction of 0.73 days per year. In addition, meat yield has increased as a proportion of the carcass, being 12% of body weight in the year 1957 and increasing to 20% in 2001 Recent work in 2017 using high density diets has shown to capacity of birds to attain an FCR of 1.19 at 2500 g live BW. Current research suggests that the optimum level of energy may be well below the recommendation by the primary breeders. For example, reducing energy from 100 to 92.5% (around -200 kcal/kg of diet) resulted in only 2 points loss in body weight corrected FCR. Indeed, very recent work showed that a similar reduction of -200 kcal/kg feed in finisher AME resulted in similar, or higher gains and breast yield while having no effect on FE. Published data regarding the balance between energy and protein in feed suggests an optimum AA density between 100 to 120% of breeder recommendations. It can be therefore suggested that today's broiler needs a higher ratio of essential amino acids to energy. In addition to a net increase in the absolute requirement of amino acids, there is an argument for higher dietary ratio of lysine: essential amino acids which will support increased meat production and may better fit modern broiler genetics.

Supplementation of methionine (Met) in broiler chicken diets is essential to support productive performance and optimise carcass yield. Met is the first limiting amino acid in corn and soybean-meal based diets for poultry. The DL-Met form is the main source used in broiler diets, but other sources such as acid free hydroxy-analogous methionine (HMA-FA) are available. Studies have indicated that the molar bioequivalence of HMA-FA is approximately 88% compared with DL-Met at 99% for growth traits. However, differences in absorption and metabolism between Met sources can influence their efficacy, especially when broilers are exposed to high temperatures. The substitution of DL-Met by HMA-FA is a potential strategy to mitigate the negative effects of heat stress because it is passively absorbed in the upper portion of the gastrointestinal tract. This review highlights the effects of substituting HMA-FA for DL-Met in diets for broiler chickens reared in different thermal environments.

Bedding material is an important requirement of floor-based poultry production systems to meet the health and welfare requirements. This substrate can be an organic material like wood or plant-based material or inorganic material like clay and sand and should generally be a good absorbant, easily available, comfortable and nontoxic to birds. Wood is an organic renewable resource having good humidity regulation and antimicrobial properties and its by-products are commonly used as poultry litter in many countries. For example, in France, wood-based bedding is used in 80% of turkey production. This litter has approximately 50% lower NH3 production compared to other materials like sand and hulls, and has multiple environment-friendly disposal options. Moreover, the birds grown on such litter show better health and welfare and they prefer to practice their natural behaviours on this material which is helpful for the amelioration of physiological status and reduction of locomotion injuries. Moreover, according to some studies, the birds show improvement in different performance parameters, for example, up to 5-7% improvement in daily weight gain, live body weight, feed conversion ratio (FCR) and survivability. These improvements may differ depending upon the production system and type of wood material used in experiments, still it can be concluded that wood-based bedding materials do not negatively affect the production potential of poultry. In addition, the antimicrobial potential of wood may help to counter the load of certain pathogens in environment of birds. This review describes the physiochemical properties of wood-based bedding materials and their role in production and welfare of poultry.

The importance of ascites in the poultry industry warrants a comprehensive systematic review and in-silico modelling to explain responses seen in previous studies in this field. By identifying the genes which are effective and relevant to different indicator traits of ascites in poultry, genes were separated base on chromosomes to determine the most effective chromosome in ascites. Consequently, 12 chromosomes have been discovered as containing effective regions on ascites incidence. Meanwhile, 24 genes including MPPK2, AT1, RhoGTPase, MC4R, CDH6, NOS3, HIF-1A, OSBL6, CCDC141, BMPR2, LEPR, AGTR1, UTS2D, 5HT2B, SST, CHRD, TFRC, CDH13, ACVRL1, ARNT, ACE, ACVRL1, MEF2C, and HTR1A affect ascites according to published studies. The results show that chromosome 9, with the presence of six related genes, chromosomes 1, 2 and 7 with three related genes and Z containing two genes have the most influence on the sensitivity to the ascites syndrome, respectively.

The Turkish poultry industry has rapidly developed in the last decade. Viral pathogens continue to threaten the industry, causing economic losses worldwide, including Turkey. At present, infectious bronchitis and infectious laryngotracheitis are major challenges, as are, to a lesser extent, avian metapneumovirus, infectious bursal disease, Marek's disease and chicken infectious anaemia. The prevalence and severity of these diseases in Turkish chickens varies depending on environmental and management factors, vaccination strategies and biosecurity measures. In Turkey, infectious bronchitis virus, including vaccine and field strains, were detected in 83.6% (41/49) and 64.2% (9/14) vaccinated broiler and layer flocks, respectively. Virulent and vaccine strains of infectious bursal disease virus were found in 83.5% (1548/1855) of excised bursa Fabricius from vaccinated broilers. Virulent Marek's disease virus was found in 19.93% (120/620) of spleens from vaccinated chickens. Infectious laryngotracheitis virus in commercial poultry and Newcastle disease in backyard chickens have been detected. To date, Newcastle disease and avian influenza virus have not been reported in commercial poultry. Avian metapneumovirus was found in 7.2% (8/110) of the broiler samples. Antibodies to gyrovirus and avian leukosis virus have been detected. Commercial vaccines, such as attenuated, inactivated and vectored vaccines, are being used for prevention and control of viral poultry diseases in Turkey. This review summarises the available information on viral poultry diseases in Turkey. It highlights the need to strengthen surveillance and reporting for diseases and addresses the vaccination practices used in Turkish poultry industry. The future prospects of vaccination and need to empower diagnostic capacity in controlling viral poultry diseases are discussed. The information presented here is aimed at improving research, prevention, and control of poultry diseases for researchers, veterinarians, policy makers and other professions related to poultry industry.

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.

The intensive production system for broiler chicken is characterised by the provision of a suitable micro-climatic condition such as temperature, airflow, relative humidity and light for proper bird's management which always, together with appropriate feeding and nutrition, favours the full growth and production potentials of the birds. Lighting, amongst other factors, is a potent and critical micro-climatic component in broiler houses as it influences many behavioural, physiological and metabolic processes in birds. To optimise the intensive system for broiler production, various lighting programmes (regarding light duration and its distribution, light colour/wavelength and light intensity) have been explored. This review compares the effects of different elements of lighting regimen on the growth performance, health, and welfare and carcass characteristics of broilers. Considering this, various degrees of intermittent photo-period (i.e. mixing photo- and scoto- periods within 24 hours) rather than one continuous photoperiod have been proven to significantly improve broilers’ weight gain by 3.4-5.8%, feed to gain ratio up to 7.3%, mobility up to 46.5%, decrease mortality rate ranging between 0.43% and 0.72%, and finally, increase carcass yield. Short wavelength lights and light intensity of ≥5 lux after the initial brooding period are said to stimulate birds’ metabolism and growth thereby, enhancing the production system. In conclusion, the lighting programme, apart from improving broiler productivity, could reduce cost expended on energy in an intensive production system.

Preadipocytes are distinct precursor cells with the ability to generate and differentiate into adipocytes - a process that is regulated by a variety of genes. Adipocyte differentiation has been extensively studied in mammals; however, little is known about adipocyte differentiation in poultry. This review summarises the isolation, in vitro culture and characterisation of poultry preadipocytes. The most commonly used method for isolating primary preadipocytes is collagenase digestion and the cells are cultured in an incubator with 5% CO2 at 37°C. Preadipocytes of most species can differentiate into mature adipocytes using a combination of growth factors (a so-called ‘hormone cocktail’), which include 3-isobutyl-1-methylxanthine (IBMX), dexamethasone (DEX) and insulin. Only the addition of a fatty acid mixture, transferrin, insulin and albumin induced primary preadipocyte differentiation, indicating that exogenous fatty acids are key factors that influence this process in chickens. As for the molecular regulation of poultry preadipocytes, studies have found several transcription factors that regulate adipose differentiation, which included peroxisome proliferator-activated receptors (PPARs), CCAAT/enhancer binding proteins (C/EBPs) and sterol response element-binding proteins (SREBPs). These transcription factors have been shown to regulate adipocyte differentiation by affecting the expression levels or activity of target genes.

Poultry production is associated with greenhouse gas (GHG) emissions but at a much lower extent than other livestock. Global production of nitrogen from poultry excreta has been estimated at about 3.29 million metric tons for meat type chickens (the average of two estimates with different assumption of 2.65 and 3.94 million metric tons) and 2.36 million metric tons for laying hens. These estimates are markedly below earlier estimates, suggesting that the issues related to loading are of a markedly smaller magnitude than previously envisioned. However, if it is assumed that 2% of the nitrogen is lost as nitrous oxide with a global warming potential (GWP) of 298 CO2 equivalents (eq.) per unit as GHG, poultry waste is contributing 33.7 million metric tons of CO2 eq./year or 0.0337 gigatons (Gt) CO2 eq./yr. This represents only 0.64% of agricultural GHG emissions. The preferred method for the disposal of poultry excreta is land application as a fertiliser with the aggregate of livestock and poultry excreta being applied to 0.3 million hectares in the USA. The environmental consequences of excreta in litter include the release of ammonia and nitrous oxide (a GHG) together with contamination of ground and surface water with nitrate, phosphate and pathogens. Alternative approaches to utilise used litter are the following: combustion, gasification, digestion and feeding to ruminants. There is scope to reduce the environmental impact of poultry production on the environment.

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.

Heracleum persicum (golpar) is an endemic medicinal plant that is commonly known as hogweed or Persian hogweed. It contains flavonoids and furanocoumarins that probably could stimulate both cell- and antibody-mediated immune responses. Besides, golpar has a substantial immunostimulatory effect on beta-lymphocytes and macrophages that played important role in antibody synthesis. Its extract at a supplementation level of 1-2.5 ml/l in drinking water showed a remarkable increase in the total immunoglobulins (Ig) (70%), immunoglobulin G (IgG) (100%) and immunoglobulin M (IgM) (94%) titres and an increase in antibody titre against Newcastle disease virus (96%) in broilers. In addition, supplementation positively affected the feed intake (9.4%), weight gain (14.7%) and food conversion ratio (FCR) (8.7%) in broilers. Moreover, in several studies, it has potential as an antifungal, antidiabetic, hypocholesterolaemic and growth enhancer agent; which endorsed its extensive contents of phytochemicals (terpenoids, triterpenes, furanocoumarins, volatile substances, flavonoids and alkaloids). It has a positive effect on the levels of glutathione (GSH), peroxidation lipids (MDA), the total antioxidant capacity of plasma or ferric reducing ability of plasma (FRAP) and glutathione s-transferase (GST), in addition to modulatory effects on liver enzymes including alanine transferase (ALT) and aspartate transferase (AST). After reviewing the published literature, it was apparent that golpar has multidimensional biological effects. Nevertheless, little research is available on the effects of golpar on productive performance and other health-related parameters in avian species. Hence, this review encourages veterinarians and poultry researcher to undertake further work to demonstrate the promising beneficial effects of golpar at effective levels to potentially replace the synthetic antibiotic growth promoters in commercial poultry diets.