Welcome to the September issue. We have a range of topics covered in this issue – including diseases, traditional and novel feed ingredients, immunity, emulsifiers and vaccines. At the editorial office, we do aim to provide a broad spectrum of topics in each journal issue, within what has been submitted, to give our readers variety.

We have made some changes in accepting papers for submission recently, so the following is an update that I hope is useful for authors. Recently, for some reason, authors have stopped uploading their copyright forms on the submission site and sending them to me instead. Please note that all copyright forms must be uploaded online at the time of submission by the authors. It wastes a lot of time at our end chasing down these forms and then having to manually upload with the publishers. Also, any revised papers must be uploaded directly using the link on the email advising of reviewer decisions. It is important that authors understand that we cannot upload revisions for them, and the system effectively stalls if this isn’t done directly online. We cannot move any papers on until this is done, and have no access to do this manually. In addition, revisions have to be uploaded via the revision link – otherwise it appears on the system as a new submission and goes back to the start of the process. I hope this is helpful to all our authors – as we try to prevent any delays in publishing as much as possible to get their papers completed in a timely manner.

As stated before, we have had a lot of papers regarding antibiotic alternatives as these are a hot topic in many countries currently. As we cannot have lots of reviews saying the same things, we have asked authors to focus on just one aspect of either a products mode of action or effects on the animal. In addition, it was decided in the latest Board meeting that summaries must be a succinct (300 word) condensation of findings of the review. This will enable others who are searching papers online to get good levels of detail from viewing abstracts.

The latter part of 2017 sees a number of conferences, including Working Group 6 Fertility at the end of August, the Meat and Egg Quality Symposium at the start of September back to back with the WVPA conference. Our Polish Branch holds their meeting mid-September, followed by the 6th World Waterfowl conference towards the end of October. Details for all related WPSA events can be found online at www.wpsa.com/index.php/calendar-home/calendar. Could anyone submitting a paper that may be suitable as a potential review for the WPSJ please contact any WPSA Board member present at the meetings, or email me. I hope all delegates enjoy these meetings, and would encourage members to attend conferences associated with WPSA. Without attendance and sponsors, such meetings would not happen, and we thank everyone for their support.

Dr Lucy Waldron

Editor

Another year ends – although with journals, one is always ahead of the fact and it is only October as I write. For our northern hemisphere members, the cold of winter looms, whilst for us in the southern hemisphere we are hoping for good weather around the corner. This current issue covers topics including sustainability, stress in laying hens and quail, amino acids and protein sources, housing and management, omega 3 oils, reproduction in cockerels, breeds, comparisons of zinc sources, immunity, consumer preferences, disease and alternative feed ingredients – so quite a spread of topics. The recent Meat and Egg conference held in Scotland is hopefully going to provide a good source of invited papers which we are working on currently. Additionally, the Waterfowl meeting in Taiwan in October will hopefully be fertile ground for new topics for our members.

Looking forward to 2018, there are many events coming up for members to attend. These include trade shows such as the IPPE in Atlanta in January, VIV MEA in UAE in February and then the 11th Asia Pacific Poultry Conference in March, to be held in Bangkok. All WPSA related events can be found on the www.wpsa.com website under Calendar – please support the sponsors of these meetings as otherwise they wouldn’t be able to take place.

I am hoping to be able to announce some news regarding a new prize for best WPSJ review paper – to be awarded annually, although the details have yet to be decided with the Board or the Trust involved – so watch this space.

Poultry continues to be a major player in global meat production, although many new challenges are heading to various countries, most notably the removal of antibiotics from animal feed in the USA and Asia. As mentioned before, this hot topic means we have had a surge of papers regarding AGP alternatives, and the message regarding specificity requirements seems to have been taken on board. Thanks to all relevant authors in this regard.

It just remains for me to wish all our readers and members a Happy New Year from all of us in the Editorial Office and look forward to seeing you at a WPSA event in 2018!

Dr Lucy Waldron

Editor

Welcome to the June issue – we have a good mix of papers with some being invited from speakers at the World Poultry Congress held in Beijing and the last WPSJ New Zealand branch meeting in 2016. Otherwise we have reviews concerning novel feed ingredients, diseases (including those which are going to be more of a problem with the anticipated limitations on antibiotic use in feed in certain regions soon), and two papers on odour. Increasingly we are receiving papers covering disease control, and we are having to be very specific regarding the content of such reviews. Any authors wishing to write about the consequences of antibiotic removal and alternatives for in-feed use need to be aware that, due to this increased submission rate, their papers must be very focussed on single areas of this topic. It’s a good idea to check back in previous issues to see what has been published before and then concentrate on other areas.

Sadly, we have also had a case of plagiarism, and have now taken extra steps in using the latest detection software to help remedy this. We are very concerned about blatant plagiarism, and any authors found doing so will have their paper revoked and will not be allowed to publish in the WPSJ again. The copyright form is a legal document, and the declarations it contains must be taken seriously by authors.

On a lighter note, there are several good WPSA meetings coming up this year, including the popular meat and egg conference in Scotland in September, which is back to back with the World Poultry Veterinary conference in the same location, which will hopefully swell delegate numbers. At the time of writing I am preparing to attend the board meeting held at the ESPN conference in Spain in May, and hope to catch up with many members there, especially our reviewers and translators who are such an asset for the Journal. Their assistance is very much appreciated.

I have been assessing our print versus online readership, and we are now down to under 2000 print copies being sent out, which is a great saving not only in costs but also environmental considerations. For any members who wish to only receive the online version of the journal, please go onto the main WPSA website for information on how to do this. The online version has features which can cut down time spent looking for certain papers – members can put in keywords which will automatically send out an email as and when such keywords appear. The online papers should be accessible well in advance of the print copy.

Dr Lucy Waldron

Editor

Well another new year and the journal is already completed for the March issue, and the June issue is almost filled as well. We often get asked by authors why we cannot publish papers straight away – which we can do to an extent, but only online in advance of the print issue, which still goes out in a quarterly fashion, and so we have to assign the papers according to the next issue available. This is something which will be discussed at our next board meeting as we strive to implement new ways to improve the publishing process for authors and maximise exposure for our sponsors. The year 2017 sees various important meetings for poultry scientists, including the 21st European Symposium on Poultry Nutrition – held at the start of May near Barcelona in Spain which is where the next board meeting will also take place. Just beforehand is the UK Spring Meeting in Chester in the UK, which is attended by scientists from various countries and is a useful place to catch up with well-known scientists as well as people in the commercial sphere. In June, France hosts the 10th European Symposium on Poultry Welfare, as well as the 10th European Symposium on Poultry Genetics. So all in all, a busy first half of the year, especially considering the numerous VIV and other commercial poultry events going on in between. Myself and the Board members try our best to get to most of these events and identify papers that we can invite from the various programs, however it is difficult to cover everything – so if any readers do see something new and exciting that is being presented that could form an innovative review paper, please do let me know.

If you are organising a WPSA related event and have suitable review papers or presenters who are covering a novel topic, please let me know. One of the main topics of discussion currently is the removal of antibiotic growth promoters in certain parts of the world (notable the USA and Australasia), following on from the stance taken in the late 1990’s in Europe. As such we have had a plethora of reviews on this topic in the last couple of months – so many that we have had to ask authors to focus specifically on one chosen area in depth as there is a huge body of work already available in this scientific field. So apologies if your paper has been returned to you with this request – it is something we have to keep a close eye on to maintain diversity and quality of the research knowledge from papers published in WPSJ.

The current issue covers various topics from alternative feed materials, welfare, disease, immunity and mineral nutrition. We are always happy to consider papers from students and on new topics, and please email me if you have a query regarding paper acceptance. I do try to catch up with various members at the events in 2017 – but until then, enjoy the latest issue of the WPSJ.

Dr Lucy Waldron

Editor

This paper presents the current situation of the global poultry sector and future trends, and discusses the challenges the sector is facing, with particular emphasis on four areas: food security, social challenges (poverty alleviation and equity), health (animal and human) and environment (natural resources and climate change). Poultry makes a substantial contribution to food security and nutrition, providing energy, protein, and essential micro-nutrients to humans, with short production cycles and the ability to convert a wide range of agri-food by-products and wastes into meat and eggs edible by humans. Poultry is the fastest growing agricultural sub-sector, especially in developing countries. The global poultry sector is expected to continue to grow as demand for meat and eggs is driven by growing populations, rising incomes and urbanisation. In this context, the sector is facing unprecedented challenges. Particularly for small holders and the poor, both in rural and urban areas, poultry is a major asset and key to poverty alleviation, providing income and market participation. Birds can be sold in times of crisis and act as household insurance. But the growing market is essentially benefiting large scale operations and access to market is critical for small holders. However, poultry represent a threat to human health, especially as a vector of infectious diseases and because of its role in antimicrobial resistance. Furthermore, poultry has a significant impact on the environment and is a large consumer of natural resources. While the sector is usually seen as efficient in converting natural resources into edible products, it uses large amounts of land, water and nutrients for the production of feed materials and contributes to climate change, mainly through feed production, and air and water pollution.

This review examines the relative bioefficacy of 2-hydroxy-4-(methylthio) butanoic acid (HMTBA) and DL-methionine (DL-Met) which includes chemical, metabolic, nutritional, and statistical aspects of its bioefficacy. The chemical, enzymatic and biological differences and similarities between these two products are explained and the evidence and reasons for HMTBA relative bioefficacy to DL-Met in monogastric animals are discussed. In addition, appropriate statistical methods for comparing the bioefficacy of these two products for successful use of each product are provided. HMTBA is an organic acid precursor of L-Met. The chemical structure differences between HMTBA and DL-Met leads to differences in how and where the two materials are absorbed, enzymatically converted to L-Met and used by the animal. Because of these differences, when the two compounds are supplemented into animal feeds in graded doses, they do not produce dose response curves of the same form due in part to differences in intake and metabolism at the extremes of the dose response curves. At deficient levels of the response curve, HMTBA fed animals may exhibit lower feed consumption and growth than DL-Met while at requirement levels they may have greater feed consumption and growth. This review provides biological evidence for why these differences in growth response occur and demonstrates that lower growth, whether for DL-Met or HMTBA, does not mean that either product is being converted to methionine inefficiently. Since the two products have different dose response curves, statistically valid methods are provided for unbiased determination of relative bioefficacy across tested dose ranges. Field nutritionists typically feed commercial doses of HMTBA or DL-Met at a total sulphur amino acid dietary level capable of achieving maximum performance. At these commercial levels, and based on the evidence, the full relative bioefficacy of HMTBA relative to DL-Met is discussed.

The levels of essential microelements in poultry feed must be high enough to satisfy the birds' requirements, yet low enough to ensure the safety of both animal feed and meat and eggs for human nutrition. The essential role of vanadium (V), chromium (Cr) and nickel (Ni) in poultry nutrition is still under investigation, while their toxicity was well established a long time ago. Even though some feeds might represent a potential source of harmful amounts of microelements, the combination of relevant quality control programs in the animal feed industry, as well as the application of good production practices and the adequate education of nutritionists can substantially reduce the risks associated with overfeeding such minerals. The aim of this review is to give an overview of the role, importance and needs of poultry for V, Cr and Ni.

Every year the growth of the poultry industry is severely threatened by a number of infectious viral, bacterial and parasitic diseases. There are a number of vaccines to control these diseases including inactivated virus vaccines, attenuated virus vaccines, live virus vaccines, and subunit vaccines, but they are often relatively expensive and require cold storage and trained people to administer them, especially in developing countries. Plant-based vaccines provide a better option to control these diseases in low profit margin poultry industry. Still there are some challenges in the field of plant-based, so called ‘green’ vaccines. Injection-based oral priming is a big challenge for commercialisation of green vaccines so, new techniques are needed in the field of plant-based vaccine to pass these barriers for commercialisation. This discusses the potential for plant-based vaccines and whether they are good option to control poultry diseases.

Dendritic cells (DC) are central regulators of immune responses and professional antigen-presenting cells (APCs) with the unique ability to induce both innate immune responses and a highly specific acquired immunity. DC communicates through chemical and mechanical signals in the initiation and maintenance of immune responses. DC forms immunological synapses with T-cells thus pulling T-cells strings and leading to activation of T-cells. Owing to their properties, DC are often called ‘nature's adjuvants’ and thus have become an important component of any vaccination strategy. Coccidiosis is a major intestinal disease caused by Eimeria spp., affecting economically valuable livestock animals such as chickens and turkeys. Economic losses are associated with decreased productivity in afflicted poultry. Vaccination strategies involving DC have been developed owing to the special properties of these cells in coordinating innate and adaptive immune responses. Vaccination of chickens with exosomes isolated from DC containing parasite antigens (Ags) represents a promising alternative strategy to control avian coccidiosis. In recent years, emergence of new chicken DC has opened a new horizon for the development of new vaccines and DC derived vaccine could be a possible strategy to control coccidiosis in field. This review summarises the current state of knowledge of DC and their specific functions in immunity against avian coccidiosis.

Odour emissions are a normal part of broiler production but they potentially threaten the sustainable development of the broiler industry. There are currently no effective methods to reduce odour emissions that are practical or affordable for use in commercial farms. Diets can be formulated to more closely meet the bird's nutritional requirements to avoid overfeeding and to reduce the excretion of undigested components. This will decrease the amount of substrates that the microbes metabolise to odorous compounds. Diet can affect gut microflora, faecal microflora, litter moisture content, pH and water activity, all of which may affect the emission of odorants. This review details the role of diets on odour emission from broiler production. In the first part of this review, key odorants from broiler production, their origin, and measurement techniques have been discussed. This is followed by the role of feed ingredients, enzymes, feed additives, minerals, dietary protein levels, necrotic enteritis and litter conditions on odour emissions. It has been reported that nutritional strategies such as partial replacement of soybean meal with meat meal in the diet, use of a low sulphur diet, low protein diet, Bacillus subtilis based probiotic and saponin may reduce emissions. Additionally, drying the litter results in lower emission of odorants including the ones that contain sulphur and prevention of necrotic enteritis and wet litter condition may also reduce odour emission from broiler production.

Avian mycoplasmas occur in a wide variety of birds including commercial poultry. The most important mycoplasmas in chickens and turkeys are Mycoplasma gallisepticum (MG), M. synoviae (MS), and M. meleagridis. Additionally, M. iowe (MI) is an emerging pathogen in turkeys, but appears to pose little issues for chickens. Pathogenic mechanisms include adherence to host target cells, release of toxins, mediation of apoptosis and immune evasion leading to obstruction of the tracheal lumen, exfoliation of epithelial cells as well as ciliostasis. In addition, mycoplasma by-products, such as hydrogen peroxide and superoxide radicals, along with inflammatory cytokines can exacerbate the disease conditions. Mycoplasmas are transmitted horizontally, from bird to bird, and vertically, from dam to offspring through the egg. The disease is diagnosed by serologic tests, cultures and PCR and is sensitive to antimicrobials whose activity is other than disrupting the bacterial cell wall. Control of pathogenic avian mycoplasmas can consist of one of three general approaches; maintaining flocks free of infection, medication, or vaccination, which are covered in this review.

Silymarin is composed of flavonolignans and derived from the dry seed of milk thistle (Silybummarianum) herb. It is used as a hepatoprotective treatment for different liver ailments, mainly cirrhosis, jaundice, growth promotant, alcoholic liver disease, chronic hepatitis C, chronic liver diseases and hepatocellular carcinoma. Reported medicinal properties are anti-inflammatory, immunomodulating, anti-diabetic, antioxidant, low toxicity, promising pharmacokinetics, protective, preventive, regenerative and antifibrotic effects and has been shown to be extremely safe. The mode of action by which silymarin might protect liver cells includes stabilisation of membranes, free radical scavenging, stimulation of hepatocyte protein synthesis and modulation of the immune response. In addition, silymarin can be used to treat jaundice disorders by ameliorating the levels of various hepatic enzymes such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Moreover, silymarin is able to moderate the immune system, by boosting IL-4, IFN-γ, and IL-10. The hepatoprotective effect of silymarin in poultry farming is poorly understood, although it may be used as a cheap, non-toxic and safe feed additive to manage liver related disorders and to replace synthetic drugs in poultry diets. Hence, this review will allow scientists, veterinarians, researchers, poultry producers to gain a pragmatic edge as well as perspective usage of Silymarin. A main priority is in finding the effective level in poultry whereby it acts as a natural liver tonic in the poultry industry and could reduce veterinary expenses.

Animals experiencing thermal stress tend to reduce heat production by limiting feed intake, with subsequent detrimental impacts on productive performance and health status. Heat stress as an environmental stressor has been an important concern among researchers, poultry producers and scientists for many decades, especially in tropical (wet and hot round the year) and arid (dry and hot round the year) regions of the world. It has been implicated in adverse marked impacts on productive and reproductive performance of quail. Several studies have investigated the negative impacts of heat stress on quail production and it has been shown that heat stress adversely affects both productivity and welfare of birds. The deleterious impacts of heat stress on different quail breeds such as Japanese quail (Coturnix coturnix japonica), bobwhite quail (Colinus virginianus), scaled quail (Callipepla californica) and Gambel's quail (Colinus gambelii) range from decreased body weight (7.7 to 13.2%), growth rate (11.0 to 14.5%), feed intake (6.1 to 21.6%), feed efficiency (4.3 to 8.6%), egg production (6.6 to 23.3%) and egg mass. Furthermore, the detrimental effects of heat stress on reproductive performance and welfare of quail have recently attracted awareness. However, further studies are required to increase the levels of information into basic mechanisms associated with the consequences of heat stress on quail. This review covers the published evidence available on the negative role of heat stress on growth performance, feed utilisation, egg production and mass, meat and egg quality and carcass traits as well as reproductive performance of quail.

Necrotic enteritis (NE) has become one of the most important diseases of modern global poultry production, with an estimated cost of around US$6 billion per annum in lost production and control strategies. The rise in prominence of NE is attributed to the prohibition of antibiotics as growth promoters (AGP) or the voluntary implementation of ‘drug-free’ broiler production programmes. Pathogenic strains of Clostridium perfringens are responsible for NE, with those expressing the NetB toxin a definitive cause in disease models. C. perfringens are normal inhabitants of the gastrointestinal tract (GIT) but these are typically non-pathogenic strains. When intestinal health is compromised, the prevailing conditions allow the establishment and proliferation of pathogenic, toxin-secreting strains of C. perfringens. The toxin(s) damages the intestinal epithelium and causes disease. Certain dietary-related factors are recognised as predisposing poultry to NE. This review will focus on the key initiators of NE and will outline the most appropriate strategies to counteract these predisposing factors and prevent NE. The continual push, globally, for poultry production programmes with less antibiotic use will sustain NE as an important and costly poultry disease that requires dietary intervention.

Avian pathogenic Escherichia coli (APEC) is one of the most economically damaging diseases affecting the poultry industry. This group of extra-intestinal E. coli causes a variety of clinical conditions including air-sacculitis and cellulitis. The economic impact of APEC is mainly due to mortality, slower growth rates and carcass downgrading. In commercial broiler operations, APEC infections are controlled indirectly by vaccination against other respiratory diseases and minimising stress conditions, and directly by administration of antimicrobial agents to suppress symptoms in infected flocks. Several studies have demonstrated that the most common virulence factors studied in APEC are rarely present in the same isolate, showing that APEC strains constitute a heterogeneous group. Different isolates may harbour different associations of virulence factors, each able to induce colibacillosis. Despite its economical relevance, the pathogenesis of colibacillosis is poorly understood. The O antigen, a component of the surface lipopolysaccharide, has been identified as a promising vaccine target. With the availability of a novel bioconjugation technology it is expected that multivalent O antigen conjugate vaccines can be produced on an industrial scale. Despite the potential for developing an efficacious vaccine to combat this economically important poultry disease, several obstacles hinder such efforts. These include cost, vaccine delivery method and timing of vaccination. The present discusses current knowledge on APEC virulence, host response to infection and various attempts to develop an effective vaccine

The intensification of poultry production has favoured the occurrence of stressful conditions such as infections, decreased feed intake, reduced feed conversion and carcass condemnation are some of the consequences of stress in birds. This stress is a consequence of the neuroendocrine-immune interplay. Neuroimmunomodulation is the scientific study of the bidirectional relation of the immune and nervous systems, i.e., physiological effects in response to exposure of animals to stressful conditions. Stress is responsible for activating the hypothalamic-pituitary-adrenal axis, which results in the production and release of corticosterone and catecholamines. Furthermore, recent studies have shown that the brain-gut-microbiota axis is responsible for the maturation and maintenance of the balance of the immune and nervous systems, which ensures improvement in the productive system. This review presents and discusses information concerning neuroimmunomodulation in birds with an emphasis on the involvement of heat stress.