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

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.

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.

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.

Chlamydia psittaci, depending on its serovar, can infect humans, birds, and other animals and livestock. Its economic impact on poultry production, especially on turkeys and chickens, and potential zoonotic risk have driven the search for an effective vaccination protocol to prevent and control the infection and shedding of the organism. Currently, no vaccine is approved for use against avian chlamydiosis despite efforts in the past decades. The present genomic era presents an opportunity to establish an effective vaccination scheme, taking advantage of the major outer membrane protein (MOMP) as the major protective antigen of C. psittaci. The plasmid DNA expressing MOMP can be coupled with optimisation of controllable factors during vaccination such as codon optimisation (through formation of polyplexes and lipoplexes), route of administration, vaccination schedule, addition of adjuvants/co-stimulatory factors such as cytokines and CpG motifs, and recombination with other poultry pathogens such as viruses. The development of an effective vaccine against C. psittaci will protect susceptible poultry from infection and production performance losses and reduce the zoonotic risk and minimise the emergence of antibiotic-resistant C. psittaci strains.

The tri-island state of Grenada, Carriacou, and Petit Martinique's legislative and institutional compliance with the World Organisation for Animal Health's (OIE) guidelines on antimicrobial utilisation in poultry production is reviewed in this paper. This includes legislative and other institutional documents, coupled with interviews with veterinary officers, health officers and managers of the veterinary drug distribution centres were conducted to evaluate the extent of Grenada's compliance with the OIE's Terrestrial Animal Health Code in the use of antimicrobials in poultry production. Five thematic areas were evaluated: 1) legislative and institutional arrangements; 2) surveillance and reporting; 3) risks associated with the importation of poultry meat products; 4) ante- and post-mortem inspection; and 5) procurement and use of antimicrobials. The information revealed that the current legislative framework in Grenada does not adequately address poultry food safety and that there is a need to strengthen the synergies between the agricultural and health sectors to enable a more thorough monitoring of antimicrobials use in poultry production. There is a need to strengthen epidemiology of zoonotic diseases, provisioning of education and information for key stakeholders about the use of antibiotics and the development of a system to monitor antibiotic procurement, distribution and use in Grenada. These findings have implications for other small island states in the Caribbean that have similar limitations in institutional capacity and knowledge deficits in the prudent use of antibiotics.

Broiler production in certain countries often suffers from an inadequate supply of local high-quality protein. Increased production of sunflower seeds (Helianthus annuus L.) for oil can provide more meal that can provide protein and offset the need for soybean meal, which is often unavailable due to cost. Presently, due to adaptive capabilities in various climatic and soil conditions, sunflower seeds are grown worldwide. Sunflower seed meal (SFSM), a by-product from oil production for human consumption, varies in quality due to variations in oil extraction methods, seed varieties and processing techniques. However, investigators reported that SFSM can replace up to two thirds of the soybean meal protein in the starter and finisher diets of broilers. This review includes the quality of SFSM as related to the effect of processing and as a feed ingredient in broilers diets.

Chicken meat is an economically important part of Chinese food security, but has suffered relatively consistent highly pathogenic avian influenza (HPAI) outbreaks since 2004. This review evaluates the extent of quantity losses caused by HPAI events on Chinese chicken meat supply and demand (domestic production, consumption, imports and exports) between 2004 and 2013, using a partial equilibrium model. The largest losses were experienced in 2004 and 2005 (4,496,700 tons) which accounted for 38.84% and 33.76% of total respectively. Across the full review period the largest impacts were on per capita consumption (2.7 million tons) followed by production (2.5 million tons), imports (0.73 million tons) and exports (0.21 million tons). Research suggests that higher imports of chicken meat during HPAI events, branding strategies and investment in food safety management through the sector may help to avoid or minimise future HPAI losses in China.

Mycotoxins are secondary fungal metabolites of structurally diverse groups occurring worldwide as contaminants of cereals such as wheat, corn, maize, peanut, and barley, which comprise the main ingredients of poultry diets. Milk thistle (Silybum marianum) has wide range of beneficial properties, including data showing its positive effects in protecting the liver of birds exposed to aflatoxins. Trials have shown that in broilers affected by aflatoxicosis, which adversely affected feed intake, weight gain, feed efficiency, serum biochemistry and immune status, supplementation of diets with silymarin reduced the detrimental effects, thereby improving the productivity and health. Although promising results have been reported, established doses and further research on the standardisation of this herb will increase its uses as alternative to synthetic drugs. The following review discusses several important aspects of the beneficial properties of milk thistle on poultry growth performance in experimentally induced aflatoxicosis.

Newcastle disease virus (NDV) was first reported in 1926. Since then, the NDV has been prevalent in domestic and wild birds representing a diverse and continually evolving group of viruses, consisting one genotype for class I NDV isolates and eighteen genotypes for class II NDV isolates. The emergence of new virulent genotypes from global epizootics and the year-to-year changes observed in the genomic sequence of NDV of low and high virulence implies that distinct genotypes of NDV are simultaneously evolving at different geographic locations across the globe. This vast genomic diversity may be favoured by the large variety of avian species susceptible to NDV infection and by the availability of highly mobile wild bird reservoirs. In certain countries such as Pakistan, the viruses of sub-genotype VIIi have replaced NDV isolates of genotype XIIIa, which were commonly isolated in 2009-2011, and have become the predominant sub-genotype causing ND outbreaks since 2012, suggesting the existence of a fifth panzootic. The genomic diversity of NDV increases the possibility of diagnostic failures, resulting in unidentified infections. Therefore, continuous monitoring of viral evolution and periodic updates of vaccine seed strains are warranted to achieve efficient control and eradication of ND. This review reports on the emergence and evolution of ND viruses and vaccination strategy in Pakistan.

Dendritic cells (DCs) are antigen-presenting cells (APCs) with the unique ability to induce both innate immune responses and a highly specific acquired immunity. DCs are crucial to induce immunity, and their maturation and functions are influenced by microbial and environmental stimuli. Chicken DCs are composed of several subtypes including bursal secretory dendritic cells (BSDCs), follicular dendritic cells (FDCs), and thymic dendritic cells (TDCs). DC maturation depends on the nature of the perturbation and permits unique and efficient immune responses for each pathogen. DCs differentially recognise the viruses, bacteria, parasite and fungi and specifically regulate the immune response. Dendritic cells (DCs) are ‘nature's adjuvants’ and, as such represent an essential component of any vaccination strategy. The understanding of DC regulatory mechanisms opens a new horizon for the development of new vaccines and their targeting with the vaccination for elicitation of better immunity levels. The following review summarises the current state of knowledge of DCs and their specific functions during host pathogens interaction.

Dandelion or Taraxacum officinale is a well-known medicinal plant that grows naturally in Europe, North and South America and Asia. Dandelion is a source of various nutrients and biologically active substances and its root and leaves contain vitamins (A, K, C and B-complex), minerals (calcium, magnesium, potassium, zinc and iron), micronutrients, fibre, lecithin and choline. The various parts of the plant have a long history of use as an herbal remedy; roots of this herb are firstly considered for enhancing digestion. Also, the roots are generally used for as liver tonic by stimulating bile production and removing toxins and re-establishing hydration and electrolyte balance. Dandelion leaves could be used successfully as digestive stimulant and diuretic. Moreover, dandelion leaves were reported to improve growth and productive performance of poultry. Several beneficial effects have been reported on intestinal mucosa regarding architecture of villi, villus height/ crypt depth ratio as well as cellular infiltration. Dandelion has many properties like immunomodulator, digestive stimulant, prebiotic, insulin stimulant, anti-inflammation, antiangiogenic, antineoplastic and demulcent. Furthermore, dandelion treats indigestion and hepatitis B infection as well as enhances metabolise androgenic hormones. Because of the scarcity of in vivo studies on dandelion, further investigations are needed to confirm its benefits and efficacy.

Probiotics are live microorganisms with confirmed beneficial effects on poultry health, growth performance, immune system and gut microbial population. A better perception of the mechanisms underlying the immunomodulatory effects of probiotic bacteria is usually needed to give a superior direction to the development and administration of probiotics. The oral administration of probiotic bacteria influence host cytokine levels and therefore, alters both innate and adaptive host immune responses. Selected probiotics, including some lactobacillus isolates and enterococcal strains, have been considered to prevent salmonella colonisation. Part of the effect of probiotic bacteria may be mediated through changes in the immune system related genes, including cytokine expression. Administration of probiotics in chickens could moderate salmonella mediated changes in genes, including encoding pro-inflammatory cytokines, T helper (Th) 1 cytokines, and Th2 cytokines. This review summarises the findings on the mechanisms of salmonella inhibition by using probiotic bacteria at the molecular level.

Emulsifiers are used in poultry nutrition for improving poultry performance, digestibility of the nutrients, especially fats, and include soy-lecithin, milk derived casein, lysophatidylcholine or lysolecithin (lecithin), bile salt, glycerol polyethylene glycol ricinoleate (E 484), and sodium stearoyl-2-lactylate (SSL) etc. The efficacy of emulsifying agents can be used with different vegetable oils and various levels of metabolisable energy (ME). The literature shows that the selection of various natural and synthetic sources of emulsifiers should be on the basis of their hydrophilic-lipophilic balance (HLB). There are new directions regarding exogenous and natural emulsifying agents, their blends in poultry diet and importance of in vitro studies. The following review includes comparisons of emulsifying agents and their impact on performance in poultry.

Mast cells (MCs) are granulated cells of haematopoietic lineage and constitute a major sensory arm of the immune system. MCs dually guard hosts and regulate immune responses against invading pathogens. This property of the MCs is attributed to their adaptability to detect stress signals and pathogens, and the production of signal specific mediators to engage immune cells for clearance of infectious agents. Pathogen-specific signals establish basis for the initiation of adoptive immune responses. These immune regulatory roles of MCs have opened avenues to engage different MCs activators which culminate in effective passive immunisation. The molecular mechanisms and dynamics of functionalities of MCs in host defences have been extensively characterised in mammals and rodents, and research on MCs in avian species is emerging. This review surveys the development, morphology and distribution of MCs in different tissues of the poultry and highlight areas that can be exploited for disease control and prevention.

Salicylate plays an important role as a non-steroid, anti-inflammatory drug. In poultry, those used most commonly are sodium salicylate (SS) and acetylsalicylic acid (ASA), due to their immunomodulatory, analgesic, antipyretic, and anti-inflammatory activities. Other effects have been reported such as minimising the effects of heat stress, allostatic load, ascites, leg disorders, reducing respiratory and digestive disorders, as well as enhancing growth performance, feed utilisation, nutrient digestion and absorption, egg production and the quality of meat and eggs. Furthermore, ASA plays a key role in lowering cholesterol and triglycerides in blood, meat and eggs, and improvements in immune functions and antioxidant enzymes have been noted in birds. This paper reviews the different characteristics and beneficial applications of ASA in poultry nutrition for improving immunity, production, and safeguarding health, especially under heat stress conditions.

Bee products, including bee pollen, offer a potential alternative to in-feed antibiotics (AGPs) currently used in poultry feed. Bee pollen is a new type of feed additives and is characterised by a variety of nutritional and bioactive properties. It may enhance the immunity of poultry, promote animal growth, protect the intestinal tract health and improve the quality and safety of animal products. Various research papers have focused on the use of bee pollen in poultry feeds, and have reported that it is, as a natural feed additive, a promising alternative to antibiotics and coccidiostats. Most papers have focussed on doses of 400 or 800 mg/kg feed, however limited dose response work has been done. Effective dose rates, dose responses and standardised products need to be established. If such consistent products can be produced, then their efficacy in terms of meat performance, carcass traits, meat quality, immunity, and blood parameters of broiler chickens can be verified, along with costs and returns on investment for producers, to establish the usefulness as an alternative to AGPs.

The emergence of microbial challenges in commercial poultry farming causes significant economic losses. Vaccination is effective in preventing diseases of single aetiology while antibiotics have an advantage over vaccination in controlling diseases of multiple aetiologies. As the occurrence of antibiotic resistance is a serious problem, there is increased pressure on producers to reduce antibiotic use in poultry production. Therefore, it is essential to use alternative substances to cope with microbial challenges in commercial poultry farming. This review will focus on the role of β-glucans originating from yeast cell wall (YCW) as a growth promoter and antibiotic alternative. β-glucans have the ability to modulate the intestinal morphology by increasing the number of goblet cells, mucin expression and cells expressing secretory IgA (sIgA) with increased sIgA in the intestinal lumen and decreased bacterial translocation to different organs. β-glucans also increase the gene expression of tight junction (TJ) proteins which maintain the integrity of the intestinal wall in broiler chickens. However, further studies are required to optimise the dosage and source of β-glucans to determine effects on growth performance and mechanisms against enteric pathogens.

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 Prof N. Yang for the translations of these summaries.