The avian egg is a nutritious food and also a major source of biologically active compounds that are beneficial for human health. These biologically active molecules are widely used by pharmaceutical, cosmetic and food industries. Egg proteins were previously studied using classical biochemical techniques such as chromatographic and electrophoretic separation and Edman sequence analysis. The development of molecular biology in the late 80's and the recent publication of the chicken genome sequence are major scientific advances leading to identification and characterization of a number of minor egg components that were not previously identified. Using recent data on the characterization of egg white and eggshell matrix proteins, we illustrate in this review recent developments in the biochemistry of the egg (proteomics) and in the molecular biology of the egg (cDNA and ESTs libraries, bioinformatic analysis of the chicken genome, transcriptomics). These methods have allowed the identification of hundreds of minor egg protein components with potential applications for industry. Functional studies to identify the biological activities of these novel egg protein components and to exploit their potential will form the next frontier of egg science.

Antimicrobial proteins are active against protozoans, fungi, viruses as well as gram-positive and gram-negative bacteria. In many cases, antimicrobial proteins are present as components of innate immunity and are capable of evading bacterial resistance mechanisms. Due to these characteristics, these proteins represent an appealing alternative to conventional antibiotic drugs. Considerable research has been conducted on antimicrobial proteins from invertebrate and mammalian sources. Within the last decade, over 20 novel antimicrobial proteins have been isolated from avian systems. The majority of these proteins has been isolated from the domestic chicken and therefore represents a minuscule fraction of the avian antimicrobial proteins that are potentially awaiting discovery. In this review, we elaborate on these discoveries and on the future of avian antimicrobial protein research.

Shea nut (Vitellaria paradoxa, Gaertner or Butyrospermum parkii, Kotschy) meal, a solid residue from the shea fat industry, is available in large quantities in West Africa. The meal is now receiving increased attention as a potential feed ingredient for poultry due to the increased amounts that are available due to high demand for shea fat in cosmetics and as a cocoa butter substitute in chocolate. Studies have shown nutrient compositions (g/kg dry matter basis) of crude protein (80–250), ether extract (17–362), crude fibre (53–138), ash (33–76) and nitrogen-free extract (318–675); probably with the major part of the variability being due to the amount of fat extraction, handling of the nuts prior to processing, or seasonal effects on nut production. Anti-nutritive factors reported include saponins (3.0–30.0 g/kg), tannins (98.7–156.4 g/kg) and theobromine (4.5 g/kg), which may have detrimental effects on performance of poultry. However, it has been shown that fermentation (i.e. wet incubation of a feedstuff) has the potential to reduce the negative effects of some of these anti-nutritive factors. It is evident that shea nut meal has low nutritive value; therefore it requires further improvements before it can become useful for the poultry feed industry.

The ontogeny of thermoregulation differs among (avian) species, but in all species both neural and endocrinological processes are involved. In this review the neural processes in ontogeny of thermoregulation during the prenatal and early postnatal phase are discussed. Only in a few avian species (chicken, ducklings) the ontogeny of some important neural structures are described. In the early post hatching phase, peripheral and deep-body thermoreceptors are present and functional, even in altricial species, in which the thermoregulation is still immature at hatch. It is suggested that the development of peripheral and deep-body thermoreceptors is not responsible for the inability to maintain a stable body temperature at cold ambient temperatures during early postnatal phase, although studies examined the ontogeny of thermoreception only in an indirect manner. Thus, other factors, such as volume to surface ratio and rate of insulation are important. Studies regarding the ontogeny of hypothalamic cold- and warm-sensitivity neurons in precocial species demonstrate that maturation of the hypothalamic temperature sensitivity takes place during the late prenatal and early postnatal period, with a relatively high cold sensitivity of the hypothalamus during the transition from poikilotherm to homeotherm. In addition, incubation temperatures are demonstrated to influence postnatal hypothalamic thermosensitivity. Brain temperature regulation is found to maturate during avian ontogeny as well and is demonstrated to coincide with the ontogenic pattern of general thermoregulation in several avian species. Relevant information of the ontogeny of the spinal cord and effector pathways related to the development of avian thermoregulation is lacking. We concluded that both prenatal and early postnatal temperature affects hypothalamic thermosensitivity and consequently condition thermoregulation in later life.

This review highlights the limited amount of research conducted regarding the optimum particle size of different feeds for efficient poultry production. The current industry practice of using highly processed, pelleted diets masks the influence of particle size, but some reports suggest that the effects of feed particle size on performance may be maintained even after pelleting. There appears to be a general consensus that particle sizes of broiler diets based on maize or sorghum, optimum particle size should be between 600 and 900 μm. Available data clearly show that grain particle size is more critical in mash diets than in pelleted or crumble diets. Although it has been postulated that finer grinding increases substrate availability for enzymatic digestion, there is evidence that coarser grinding to a more uniform particle size improves the performance of birds maintained on mash diets. This counter-intuitive effect may result from the positive effect of feed particle size on gizzard development. A more developed gizzard is associated with increased grinding activity, resulting in increased gut motility and greater digestion of nutrients. Although grinding to fine particle size is thought to improve pellet quality, it will markedly increase energy consumption during milling. Systematic investigations on the relationships of feed particle size and diet uniformity with bird performance, gut health and pellet quality are warranted if efficiency is to be optimised in respect of the energy expenditure of grinding.

Many avian species are considered sexually monomorphic. In monomorphic bird species, especially in young birds, sex is difficult to identify based on an analysis of their external morphology. For nestlings, sex identification is usually impossible by morphological examination. Sex identification in avian species is one of the key points of avian breeding and evolutionary studies. Through the knowledge of sex identification genes, poultry breeding programmes can be applied more successfully. Vent sexing, laparoscopy, steroid sexing and karyotyping are methods for sex identification used in monomorphic birds. However these methods are unreliable, time-consuming, and expensive while some of them could be painful and even lifethreatening for birds. The sex of an individual is established from the genes located on sex chromosomes. Female birds carry one copy of both Z and W, and male birds carry two copies of Z avian sex chromosomes. However, there are many DNA techniques, the most reliable one is amplifying sex specific CHD1 gene by P2 – P8 primer pairs.

This review summarizes the environmentally friendly methods that are available to manage phosphorus (P) excretion. Phase feeding reduces P excretion up to 10–25% by adding precise amounts of P to broiler diets. Increasing of the Ca:P ratio in diets from 1: 1 to 2: 1 decreased the availability of P from phytic acid. Feeding diets supplemented with vitamin D can increase phytin P (PP) utilization from 31–50 to 68–87%. Total P (TP) excretion by poultry may be reduced by up to 50% through the use of supplemental phytase. Reductions in phytic acid P ranging from 50 to 65% with no decreases in TP of the seed were seen in ‘low-phytic acid’ or ‘high-available P’ (HAP) mutants when phytase supplementation was contained in diet. However, total activity of phytase was 35% higher in the small intestine of laying hens because of different pH. And both microbial phytase and lactic acid enhanced the apparent total tract digestibility (ATTD) of ash, Ca and Mg and apparent ileal digestibility (AID) of phytic acid.

Fat content in poultry meat is relatively low (2.8 g/100 g breast and 13 g/100 g thigh) and with a positive unsaturated/saturated fatty acid ratio, from a human health point of view. It is well established that we can modify lipid fraction through dietary strategies in order to improve nutritive value. When the dietary polyunsaturated fatty acid (PUFA) level increases, the PUFA content in the chicken tissues also increases. But this enrichment in PUFA, especially in omega-3, leads to a higher number of double bonds in the meat and this provokes different consequences. The use of dietary PUFA fat causes a decrease in the body fat deposition in broilers. Furthermore, an increase in the degree of PUFA in meat enhances the development of organoleptic problems and increases the susceptibility to oxidation. Since antioxidants, especially vitamin E, protect PUFA from oxidation damage, its inclusion in chicken diets must be assured. Alpha-Tocopherol (alpha-Toc) content in poultry meat increases linearly as the dietary alpha-Toc supplementation increases, but it is affected by the PUFA content. As the dietary PUFA level increases, the alpha-Toc content of chicken meat decreases. To achieve the same tissue alpha-Toc concentration, the vitamin E requirements increase by 2.5 and 3.7 mg per each g of dietary PUFA. The potential healthy beneficial effect of PUFA enriched meat will be limited if the antioxidant content, such as vitamin E, which prevents oxidation, is not assured. The dietary supplementation with alpha-Toc and PUFA should be adjusted depending on our aims: nutrient enrichment and/or lipid oxidation minimization.

Broiler breeder hens grow more efficiently and are leaner than ever before due to positive results from broiler genetic selection strategies. Quantitative feed restriction is used to limit excessive weight gain and maximize egg production and fertility. Over the past 30 years, broiler breeder body weight (BW) targets have undergone change, although the degree of change is small compared to the large increases in growth potential. As a result, the degree of feed restriction needed to maintain broiler breeder BW targets has increased, which is a welfare concern. The objective of this study was to examine current and historical broiler breeder BW targets for three major broiler companies to assess the extent of changes in BW targets over time and to explore potential reasoning behind shifts in these growth targets. By comparing breeder parent target BW profiles with corresponding potential broiler growth, changes in the apparent severity of feed restriction of the broiler breeder of this strain were calculated. Factors affecting the interpretation of degree of restriction values were discussed in combination with current initiatives underway to alleviate the severity of feed restriction. This information is intended to demonstrate how management of broiler breeder stocks has changed in time and to provide context for a realistic measure of the degree of feed restriction in broiler breeders.

The conditions under which laying hens are kept remain a major animal welfare concern. It is one of the most intensive forms of animal production and the number of animals involved is very high. Widespread public debate has stimulated the call for more animal friendly, alternative systems to barren conventional cages. Directive 1999/74/EC has encouraged technical changes in current systems. Not only have traditional cages been modified (so-called ‘enriched cages’), but also new alternative systems (e.g. aviaries) have been developed. There is an ongoing need to evaluate the actual welfare status of hens in these novel systems including those on commercial farms.

The LayWel project, was funded via the European Commission's Sixth Framework Programme and national funding from several EU countries. Its general objective was to produce an evaluation of the welfare of laying hens in various systems, with special focus on enriched cages, and to disseminate the information in all member states of the EU and associated countries. The project took into account pathological, zootechnical, physiological and ethological aspects.

A major achievement of the LayWel project was the compilation of a database collecting data from different housing systems and thus enabling data comparison. The project partners recommend that support is given to maintaining the database in the future so that data can be more reliably modelled.

As the type of data collected did not often allow a formal statistical analysis the evaluation of welfare was a presentation of risk factors and advantages and disadvantages of various housing systems. Conclusions are that, with the exception of conventional cages, all systems have the potential to provide satisfactory welfare for laying hens. However this potential is not always realised in practice. Among the numerous explanations are management, climate, design, different responses by different genotypes and interacting effects.

A second major achievement of the project was the development of feather scoring and integument (skin, head and feet) scoring systems together with comprehensive sets of photographs.

It is recommended that the integument scoring systems are widely adopted and used in on-going research. Farms should also routinely and frequently carry out integument scoring to assist in the detection of damaging pecking, which is currently a widespread welfare problem.

Within LayWel an on-farm auditing procedure was developed in the form of a manual for self-assessment. The manual first explains what is meant by welfare and outlines the relevance of welfare assessment. It also summarises risks to welfare in the main categories of housing system. The second part contains recording forms, with guidance for assessing hen welfare. These enable regular checks of a range of indicators of laying hen welfare to be carried out systematically. The indicators were chosen to be relevant to hen welfare as well as feasible and reliable to apply in practice.

A series of conclusions and recommendations were made on various aspects of housing systems, behaviour, health and mortality and other matters in relation to bird welfare. Full details of these and all other aspects of the LayWel project can be found on www.LayWel.eu. The information is also available on CDROM of which copies are freely available on request.

Chickens are the most popular poultry worldwide and are now used for both meat and egg production. There is only a sporadic information in the literature on chicken taxonomy; and there is a lack of a single concise document that deals with different issues related to this important topic. The present document contains detailed information on the tree taxonomy of chickens. In addition, process of domestication and its effect on chicken genetic diversity, physiology and behaviour are also discussed. The major conclusions are as follows: 1) Chickens are classified as: order: Galliformes, family: Phasianidae, genus: Gallus (junglefowl). Four species of junglefowl are recognized. These are: a) Gallus gallus (red junglefowl), b) Gallus varius (green junglefowl), c) Gallus sonneratii (grey junglefowl) and d) Gallus lafayetii (Ceylon junglefowl). The current chickens that are used for both meat and egg production commercially are domesticated fowl and are the descendants of the red junglefowl species. 2) Domestication process is a complicated one and involves intensive breeding and selection programmes. During this process, genetic diversity is still maintained, yet reduced, so careful attention is needed in the future to maintain the diversity of specialized chicken species. 3) Domestication resulted in basic changes in the behaviour, physiology and production of the bird, but still there are some similarities between the ancestor and the current chickens.

Production of poultry in the Lao People's Democratic Republic is described. Data from field surveys and from Government and other documents are analysed. Some 95 per cent of poultry are kept in the village, mainly scavenging, system and only 5 per cent are found in industrial systems. Poultry (domestic fowl, two duck species, turkey, Chinese goose, pigeon and other species in that order of importance) are kept by about 90 per cent of households. In absolute terms greatest numbers are found in the northern and central parts of the country. More birds per person are kept in the less developed northern and southern regions. “Average” households own a mixed flock comprising 14–20 domestic fowl, 6–10 ducks, 2–6 turkeys and geese and a flock of pigeons although most owners raise only fowl and ducks. Genetic resources are almost entirely indigenous or naturalized except for a relatively small number of hybrid domestic fowl for industrial egg and meat production. National poultry meat production in 2000 was estimated at 12 800 tonnes and egg production at 10 700 tonnes. Production per bird is 25–60 eggs per year for scavenging fowl and common Anas ducks and slightly less for Muscovy ducks. Village poultry products are consumed at home or sold in local markets. There is growing urban demand from which small scale producers should be able to benefit. Disease is an important constraint to production. Newcastle disease is the main problem in village flocks. Avian Influenza is of concern in the commercial sector. More attention should be given to smallholder producers. This, together with interventions in housing and sanitation and in nutrition and disease control, would greatly increase output. Smallholder producers would be the principal beneficiaries of these interventions in improvements to food security and nutritional status and in reduced production risk.

Over the past 40 years there have been many changes in egg production and processing, as well as, the egg itself. Many of these changes have contributed to the microbial challenges of the egg that we face today. Salmonella enterica serovar Enteritidis (SE) and more recently Salmonella enterica serovar Heidelberg (SH) are the two organisms of most concern associated with eggs. Most U. S. egg producers utilize some type of control programme to ensure egg safety. Many use the United Egg Producers' “5-Start” Food Safety Programme. Commercial egg washing significantly reduced concentrations of aerobic bacteria, yeasts and moulds, Enterobacteriaceae, and E. coli on shell egg surfaces. However, refrigeration of eggs is often identified as one the most critical issues in minimizing the risks associated with Salmonella contamination in eggs. The condensation question always arises any time egg refrigeration is discussed. Moisture often condenses on the shell surface when cold eggs are moved from the cool storage into hot and/or humid conditions. Research has shown that the ability of any microbes present on the shell to penetrate the shell was not increased with egg sweating. Also, heat sensitivity of SE can be induced by exposure to low temperatures. Although low numbers of SE and SH can contaminate eggs via the transovarian or shell penetration route, these small numbers cannot be ignored. Storage at temperatures as low 4°C combined with natural defences does not completely prevent growth. Furthermore, rapid growth occurs at 25°C, so minimal temperature abuse could result in high levels of contamination within eggs. The need for proper management during production, properly controlled storage, cooking and serving is critical.

27 Creole and 27 Plymouth Rock×Rhode Island Red hens (cross) 47 months old were used to estimate the effect of three diets; commercial diet, corn+alfalfa and homemade diet on egg weight, white, yolk, egg shell, dry matter, protein, fat and ash content of the yolk; lipid fraction and fatty acid profile of the yolk was estimated too. Eggs were collected at 53 weeks of age, 30 eggs per treatment were randomly selected for laboratory analysis. No differences (P>0.05) were found on egg, white, yolk and egg shell weight between genetic groups; inside groups there was a significant effect of diet on yolk weight in both groups. There was no effect of diet and genetic group on yolk composition (P>0.05); however there was a trend of less content of dry matter and more ash with the homemade diet in both groups. There was a group effect (P<0.05) on cholesterol, cholesterol esters and lecithin content; inside groups there was a diet effect (P<0.05) on total lipid content and triglycerides. No differences (P>0.05) between groups were found for the fatty acid profile; inside groups stearic acid was higher (P<0.05) in the yolk of hens fed with no commercial diet and linoleic acid percentage was higher (P<0.05) with corn plus alfalfa diet. Results indicated that corn+alfalfa and homemade diet seem to alter the egg components, yolk lipids and fatty acid profile.

In chickens and in animals in general, growth is influenced by genotype as well as by environmental factors including nutrition. Hormonal changes form, in part, the causal link between these interacting factors and the physiological processes leading to growth. It is well established that growth-related hormones (GH, SS) play different roles in different tissues. Several studies have investigated the nutritional and/or genetic effects on growth in chickens, leading to the general conclusion that the improvement of growth in modern broiler chickens is largely influenced by the genotype. In addition, it has been shown that the nutrition-determined regulation of tissues is also genotype-specific.

Besides growth, genotype-nutrition interactions also influence reproductive parameters (sexual maturation, egg production) and their endocrine control (hormone levels), apparently having long lasting (or epigenetic) effects for the entire lifespan. Especially for broiler breeders, these interactions are of importance in terms of a long-term solution for the broiler breeder paradox. Indeed, broiler breeders need the genetics for rapid growth and yet have to show a high rate of egg production, in spite of the long recognized negative relation between growth and reproductive fitness. Currently, restricted feeding is the only practical tool available to obtain an optimal equilibrium between growth and reproduction. This has the potential for the impairment of welfare (hunger, behaviour, health, viability). Recent studies suggest that modifying the timing of restriction programmes, the quantity/quality of the diet or the use of genotypes that tolerate ad libitum feeding may achieve a good balance between growth and reproductive performance on the one hand and breeder welfare on the other.

By using a lighting programme with an 18 h long daily photoperiod for 2 to 2.5 months starting in winter (December to January) and 11 h short daily photoperiod from spring (March) to autumn, the breeding season of Greylag geese in Guangdong Province, China was successfully altered to achieve out-of-season lay in the natural non-breeding seasons in the spring and summer months. Application of such out-of-season laying technique on gosling production, resulted in economic benefits of earnings 5 to 6 times higher than conventional production, and doubled profits of commercial goose meat production using out-of-season management programmes compared with using conventionally produced goslings. In addition, using the out of season laying technique balanced the whole year's geese production, goose meat consumption and also stimulated market growth. Development and application of the out-of-season laying technique, together with the resultant economic benefits, lead to modernization and sustainable development of the goose industry in Guangdong Province, as represented by growth of farm or flock sizes, a decrease in farm numbers and the use of modern nutrition, disease prevention and breeding programmes.

The main objective of this work was to describe the characteristics of and major constraints to village chicken production in Myanmar. Data on village chicken production, health, husbandry and marketing were collected in 296 households in 10 villages in the Yangon division of Myanmar in November 2003. The average flock size in the study area was about 30 birds, comprising 12 chicks, 12 growers, 4 hens and 2 cocks. Disease as a cause of mortality was more prominent in growers and adults, while predation and exposure to unfavourable environmental conditions were major causes of mortality in chicks. The main predators identified were: birds, rats, snakes, dogs and cats in 32, 31, 17, 15 and 3% of households respectively. Two main strategies were identified to improve village chicken production: vaccination as a means of protecting birds against Newcastle disease and confinement rearing and supplementary feeding of chicks, as a means of reducing the attrition rate of young chicks. This is the first survey conducted describing village chicken population structure and productivity in Myanmar.

Most rural households have poultry cared for by women, children and vulnerable people – the aged and physically challenged. Family poultry generate 19–50% of rural family income, make up about 77% of the national flock and contribute about 98% of poultry products consumed in the villages of developing countries. Households that accept innovation for semi-scavenging poultry production usually increase weekly consumption of eggs and meat. The importance of family poultry in assisting the landless poor and the destitute is reflected in many national poverty reduction strategy programmes which identify family poultry as one of the keys to accomplishing the millennium development goal of reducing the number of poor by half before 2015. There are few other alternatives in the livestock sector that can be used to reach so many poor people in rural areas. Wherever HPAI occurs in family poultry, it will wipe out the contribution of family poultry to family food security and to family income. While compensation and restocking are important, the greatest need of smallholder poultry producers faced with the challenge of HPAI is for information, knowledge and training for HPAI-safe family poultry production.

The current Highly Pathogenic Avian Influenza (HPAI) crisis, involving the H5N1 subtype, has developed quickly and has overwhelmed the human resource capacity of both international agencies and national governments in many affected countries. It has been recognized that the best way of preventing the emergence of a pandemic influenza virus of avian origin is to control the virus at source. The H5N1 subtype is now endemic in a number of countries and it has become clear that its control and eventual eradication will require a medium to long-term strategy involving multiple stakeholders. A common understanding of the problem and effective education and communication components are important elements of the control strategy. This paper reviews the challenges involved with the development of effective communication materials and methodologies for the wide range of partners involved in the prevention and control of HPAI, the communication lessons learnt to date and makes recommendations for improving the effectiveness and efficiency of communication activities in the future.