The growing scepticism of the public towards intensive poultry production provided the background to a joint project of the University of Vechta and the Poultry Association of Lower Saxony in 2012. The main goal of the transparency project was to provide a realistic impression on modern, market-oriented poultry production on family farms by opening poultry houses to the public. From 2012 until 2015, 36 farms in Lower Saxony opened their doors and 9,000 visitors made use of the possibility to visit layer, broiler and turkey farms. The visitors were interviewed prior to the farm visit and after they had left the poultry houses. 2,922 questionnaires of persons older than 18 years and without a former knowledge about intensive poultry production were evaluated. The results presented in this paper show that farm openings changed the attitude of the visitors considerably and that they were less sceptical towards intensive poultry husbandry than prior to their visit. The project will be continued until 2019.

Salmonellosis is a typical zoonotic disease that occurs frequently in poultry flocks. Many salmonella serovars have been found to be responsible for this disease. In this review besides, poultry as a carrier of Salmonella enterica serovar Typhimurium infection, various infectious routes, pathology, sources of infection are discussed as well as diagnostic measures and preventive strategies that aim at reducing the incidence of salmonellosis at the farm level. Among the different diseases occurring in poultry, those caused by the genus Salmonella is the most common, causing serious losses to the poultry industry in terms of mortality, reduced growth and loss of egg production. The diseases caused by S. enterica serovar Typhimurium have got public health significance, as well as being associated with food poisoning in humans. Salmonellosis in humans is mainly caused by S. typhimurium. The ability of this serovar to infect birds and contaminate eggs makes it a potent infection agent for humans. As S. typhimurium shows foodborne pathogenesis, it is important to comprehend how it can affect eggs and what strategies are needed to enhance control over infection.

Cholesterol plays an essential role in the synthesis of cell membrane, bile acids, and steroid hormones as well as vitamin D. Dietary cholesterol comes from only animal sources, such as meat, butter, cheese and eggs, and contributes about 20% per day to the body pool in humans. Chicken egg, which is a good source of essential amino acids, fatty acids, vitamins and minerals, contains approximately 213 mg cholesterol. Data available related to egg intake and the risk of cardiovascular disease (CVD) is inconsistent. Early research suggested that egg intake elevated plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) identified as a major risk factor for CVD in humans. Recent studies show that dietary cholesterol may not be the actual factor in an individual's plasma TC, LDL-C and CVD. According to the latest nutrition recommendations, one egg may be eaten as long as one's total daily dietary cholesterol is limited to ≤300 mg per day. Health professionals suggest restricting dietary cholesterol to avoid elevating blood LDL-C and risk of CVD. This suggestion influences per capita consumption of the egg playing an important role in the nutrition of children and elderly people. This review focuses on egg intake, LDL-C and TC levels in the blood and the regulatory mechanism maintaining the homeostasis of serum cholesterol in the human body.

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.

Poultry can be exposed to different kinds of immunosuppressive agents that impair health and welfare by destroying innate and acquired immunity leading to diminished genetic potential of poultry for efficient production. Immunosuppression is a condition characterised by humoral and cellular immune dysfunction that leads to increased susceptibility to secondary infections and vaccine failure. Immune dysfunction at the humoral level is largely due to change in soluble factors mediated by complement or chemokines for innate immunity or due to alterations in antibodies or cytokines for adaptive immunity. In contrast, immune dysfunctions at cellular levels include alterations in neutrophils, monocyte/macrophage, and natural killer cells for innate immunity or changes in B or T lymphocytes for adaptive immunity. In poultry, stress-induced immunosuppression is manifested by failure in vaccination, and increased morbidity and mortality of flocks. Immunosuppressive agents can have cytolytic effects on lymphocyte populations leading to atrophied and depleted lymphoid organs. Immunosuppression can be due to infectious agents or non-infectious agents or due to a combination of them. At present, several modern cellular and molecular approaches are being used to determine the status of the immune system during stress and disease. Comprehensive methodologies for the evaluation of immunosuppression by combined non-infectious and infectious aetiologies have not found general application. Currently, investigations are being developed in order to detect genetic expression of immunologic mediators and receptors by microarray technology. It is likely that this new technique will initiate the development of new strategies for the control and prevention of immunosuppression in poultry. A long term immunosuppression preventive approach involves genetic selection for resistance to immunosuppressive diseases. In general, intervention approaches for immunosuppressive diseases largely rely on minimising stress, reducing exposure to infectious agents through biosecurity, and increasing immune responses by vaccination against immunosuppressive agents.

L-carnitine (B-hydroxy-Y-N-trimethyl aminobutyrate) is a water-soluble product, found in animals, plants and microorganisms. Its synthesis takes place from two important amino acids, lysine and methionine. Essentially, L-carnitine has an intermediary role in metabolism. It promotes energy metabolism for cell and regulates co-enzyme A concentration in cystosol and mitochondria, which are important in glucose and lipid metabolism. L-carnitine was first isolated from the chicken embryo in a significant amount, but is absent in the egg. Under normal physiological conditions, the endogenously synthesised levels are sufficient for normal growth and functions. Its requirements are increased in stressful conditions and during metabolic and physiological higher demands, such as growth and laying periods. L-carnitine increases energy production, fat metabolism and improves immune status in birds, which is energy demanding. In this review, several aspects of the beneficial effects of dietary supplementation of L-carnitine on poultry health and production are briefly summarised.

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.

Flavonoids are natural compounds derived from fruits, vegetables and medicinal plants. These compounds have been reported to possess various biological actions including anti-inflammatory, antioxidant, growth promoter, antiviral, hepatoprotective, antibacterial, antiallergic, anticarcinogenic, antithrombotic and immunomodulator activities in various animals and poultry species. Quercetin is found in various foods such as vegetables, tea, fruits, wine apples and onions and is known to exert positive effects on poultry production and health. Since, quercetin enhances the immune system by stimulating lymphocytes, macrophages and IgY antibody production and improving natural killer cell activity, lymphoid organs (spleen, thymus and bursa) weights as well as activating the cytokines profile, its supplementation can lead to a state of immune alertness and a lower incidence of infections and diseases. In addition, it affects the dendritic cells (DCs) that play an important role in adaptive and innate immunity. Quercetin revokes the ability of lipopolysaccharide (LPS)-stimulated dendritic cells to induce specific T cell activation and reduce the cytotoxicity in both in vivo and in vitro studies, suggesting quercetin works as an immunosuppressive agent. As immune function is crucial for poultry productivity and prosperity, this review elucidates the potential nutritional effects and health benefits of quercetin on poultry as a replacer for traditional immune boosters and growth promoters. It includes the antiviral activity of quercetin against influenza A virus, rhinovirus (caused common cold), adenovirus (source of necrotic pancreatitis in broilers) and suggests its role in counteracting heavy metal toxicity. However, further studies on molecular basis are required to understand mode of action, beneficial applications as a natural feed additive, growth promoter and immune enhancer, beside the side effects of this compound in poultry.

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.

Antibiotic resistance has led poultry nutritionists to find alternatives for antibacterial growth promoters in broilers. Among these substitutes, one is mannan oligosaccharides (MOS), a yeast cell wall derived prebiotic. MOS decreases the load of pathogenic bacteria through 1) binding bacterial type-1 fimbriae 2) increasing goblet cells which produce bactericidal mucin and 3) providing favourable environment for the growth of beneficial bacteria leading to competitive exclusion. Balance between pathogenic and beneficial bacteria causes increase in villus length and decrease in crypt depth which are biomarkers for gut morphological improvement. As structure is equal to function, improvement in intestinal morphology increases activity of digestive enzymes and ultimately improves digestion. Besides these, immunomodulatory effect of MOS activates macrophages of gut associated lymphoid tissues resulting in improvement in cellular, humoral and cutaneous immunity. MOS also increases production of butyric acid and decrease pH of intestine in broilers. Though these combined mechanisms, MOS improves growth rate and performance of broilers.

Glycerin or glycerol (C3H5(OH)3) is one of the most valuable and versatile chemical materials known. The term ‘glycerin’ refers in general to a commercial solution of glycerol in water of which the main constituent is glycerol. Glycerin is an odourless, colourless, viscous liquid with a sweet taste. It is completely soluble in both alcohol and water. Glycerin is the main co-product derived from biodiesel production. It is produced by a KOH- or NaOH-catalysed transesterification of the triacylglycerols in fat or oil along with an alcohol. Glycerin is an important ingredient for the production of soaps, cosmetics, pharmaceuticals and food. Additionally, glycerin is highly stable under normal storage conditions, practically non-irritating in its different uses, suitable for interactions with other chemical materials and has no any negative environmental impacts. Nowadays, with increasing glycerin production and its availability on the market, many new and novel uses are expected to be developed, particularly as alternative energy source for poultry diets. Furthermore, glycerin plays an essential role in body cellular metabolism. This review paper discusses the various trials using glycerin in poultry diets as an energy source and its effects on different parameters in the birds. Generally, poultry diets, which included glycerin up to 10% in feed, gave positive responses in most of studies, some of which measured apparent metabolisable energy (AMEn). However, more indices need to be determined in further studies in different poultry species.

Application of chicken manure is commonly practiced in the horticultural industry due to its value as a fertiliser, ability to improve soil properties and relatively low cost. An unpleasant odour is inherently associated with poultry manure and is considered one of the major limitations in applying chicken manure to production land. Odours originating from chicken manure result from a combination of up to 150 compounds including volatile fatty acids, mercaptans, esters, carbonyls, aldehydes, alcohols, ammonia and amines. Odours are mainly generated by decomposition of chicken faeces, feathers, spilled feed, dust and bedding materials. Issues related to odour from chicken manure are associated with three main locations: sites of production and land application and storage areas. Many strategies have been tested for odour management at production sites, however, odour control, associated with storage and land application, are yet to be addressed. Since odour management is one of the major elements of overall environment management in crop production, this review provides an assessment of odour issues associated with use of chicken manure in the horticultural industry with special reference to minimising odour at storage and land application sites.

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.

Having accurate data for ileal amino acid digestibility of a feed ingredient is one of the ways to enhance protein and nitrogen utilisation, improve poultry feeding efficiency, and mitigate ammonia emission and pollution in the environment. Moreover, the precise estimation of endogenous amino acid losses (EAAL) depends on formulating diets on digestible amino acid (DAA) basis. Numerous methods have been reported to determine the endogenous fractions including the regression method, the protein-free diet, and the total digestible nitrogen diet. The EAAL determined by these techniques can help in calculated corrected values for amino acid digestibility, termed true digestibility. Certain dietary components that can be called ‘specific losses’ could lead to higher losses than the basal calculation would indicate. To determine the basal plus specific losses (total endogenous losses), some researchers suggested the 15N-dilution method, which allows the determination of the actual digestibility. This method needs more studies and evaluations because there are some controversial issues about this methodology, such as the validity of the 15N-dilution technique when applied to any amino acid or to total nitrogen, the reference pool for the estimation of the labelling of endogenous fractions/secretions, anti-nutritional agents, the effect of bird age, mucin, different cereal grains, as well as the marker itself and the proper assessment. This review will be focused on the above issues, finding that the recently reported 15N isotopes single injection method could be an easy, time-saving, consistent, and reliable methodology for EAAL estimation in poultry.

The reduction of reproductive performance associated with stress is a known phenomenon in domestic birds. This review demonstrates the involvement of glucocorticoids, a stress hormone, in the decision-making process regarding energy ingestion and distribution in laying hens. During the energetic challenge induced by a stressful environment, corticosterone stimulates energy intake and a preference for a high-fat diet by up-regulating neuropeptide Y (NPY) expression via the AMP-activated protein kinase (AMPK) pathway. The elevated corticosterone levels in response to stressors may be associated with suppressed reproduction in laying hens via a possible perturbation of the hypothalamic-pituitary-gonadal (HPG) axis. Corticosterone suppresses follicular development and is energy dependent by decreasing the availability of the circulating yolk precursor and the prevention of yolk deposition in follicles. Energy status is also involved in rejuvenation in moult hens.

The liver is the ‘central laboratory’ of a chicken's body, responsible for sorting and transforming digested compounds as well as dealing with waste products. It is essential that this organ is kept in an excellent condition in order to maintain a healthy bird. Viral hepatitis in poultry is a complex disease syndrome caused by several viruses belonging to different families, including fowl adenoviruses (FAdV), avian hepatitis E virus (HEV), duck hepatitis virus (DHV), and turkey hepatitis virus (THV). Although, these viruses target the liver primarily, they each possess unique clinical and biological features. Hydropericardium syndrome (HPS) is a highly infectious disease caused by FAdV serotype 4 (FAdV-4) affecting poultry, especially broilers, and is characterised by the accumulation of fluid in the pericardial sac and hepatitis. Inclusion body hepatitis (IBH) was recognised firstly in the US, and the disease has now been reported in many countries. FAdV, the causative agent of inclusion body hepatitis, is a Group I avian adenovirus in the genus Aviadenovirus. The affected birds have a pale, swollen, friable, and haemorrhagic liver with pathognomonic histological lesions including intranuclear inclusion bodies in the nuclei of the hepatocytes. Avian HEV naturally infects chickens and is associated with hepatitis-splenomegaly syndrome, although the majority of the infected birds are subclinical. THV is a picornavirus that is likely the causative agent of turkey viral hepatitis. Currently there are more questions than answers about THV, and pathogenesis and clinical impact remains largely unknown. Future research into viral hepatic diseases of poultry is warranted to develop effective vaccines, specific diagnostic assays, and identify suitable cell culture systems for virus propagation. This review covers the common and unique features of major hepatitis causing viruses, with emphasis on FAdV, HEV and THV in an effort to identify the knowledge gaps and aid prevention and control of poultry viral hepatitis.

Avian tuberculosis is a chronic infectious disease caused by M. avium including four subspecies Mycobacterium avium subspecies avium; M. avium hominissuis; M. avium paratuberculosis; M. avium silvaticum. This disease is characterised by the formation of granulomatous lesions in viscera, a progressive weight loss and death. It can be transmitted to healthy birds in the flock, and occasionally to human beings. It is important to diagnose avian tuberculosis in order to prevent the spread of infection and epidemiology. This paper reviews the available techniques for the diagnosis of avian tuberculosis along with their pros and cons. The main problem in diagnosis is poor availability of samples due to infrequent shedding in faeces, pattern and colour of feathers, wattle and comb and lack of specific signs and symptoms. Any single technique is not effective in diagnosing the disease due to the lack of required sensitivity and specificity. Application of two or more techniques is not a feasible option in developing countries due to financial constraints. In the short term, more research is needed to develop multidisciplinary approaches which can help fully understand the aetiology and epidemiology of disease.

The Korean native chicken (KNC) is believed to have existed in the Korean Peninsula more than 1,400 years ago. Since then, KNC have been bred only by private farmers in rural areas of Korea. In 1994, a KNC conservation program was established by the Korean government and, as a result, five lines were restored. KNC are considered to have a unique taste and texture that is more attractive to Korean consumers than meat from commercial broilers. However, the price of KNC is relatively high, which is mainly due to the breed's low growth rate, hence the limitations for industrial applications. In addition, their unique taste and texture in comparison with that of other broilers has been evaluated by scientists over the past few years. The general composition, physiochemical traits, content of taste-active and endogenous bioactive compounds and sensory quality of KNC meat, as well as breeding history are reviewed in this paper. The information from this review can be used for the development of commercial KNC breeds and can be applied to models for the commercialisation of native chicken breeds in developing countries.

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.

Growth is a key characteristic of animals and can be defined as any change in body size per time unit, and is influenced by genotype and environment. Mathematical functions called ‘growth models’ have been used to explain the growth patterns of poultry species. These semi-mechanistic growth models have a non-linear structure, sigmoid shape, and certain biologically meaningful parameters. In poultry science, Gompertz, Logistic, Richards and von Bertalanffy functions have been commonly used to model the growth patterns of birds. In this review, the studies concerned have been summarised under the titles ‘determination of the best-fitting growth model’, ‘a comparison of the growth of poultry species or various experimental groups’, and ‘genetic parameter estimates for growth curve parameters’. This review discusses existing and new approaches to growth modelling.