Education is one of the founding pillars of the World's Poultry Science Association (WPSA). The Association regards most of its activities as contributing to education. The Journal, now in its 62nd volume, presents review articles on a diverse array of subjects concerned with poultry science. In addition, the Journal contains details of upcoming educational courses at a variety of institutions around the globe.

World Congresses, Regional Conferences, Symposia and Workshops provide educational opportunities at a variety of academic levels. WPSA provides scholarship opportunities for young scientists to attend these events and also contributes to faculty support through its Speakers' Bureau Programme.

The Association also cooperates with the Dutch organization, Agromisa. Together they are producing poultry management manuals for use in developing countries. The International Network for Family Poultry Development operates in developing countries to improve poultry management at the village level, thereby raising the nutritional status, as well as economic activity, among some of the world's most vulnerable and poor people.

From this, it can be seen that the WPSAoperates at every level of poultry keeping, to improve the competence of those involved. These activities are supported by both the world and branch organizations.

Necrotic enteritis is a disease in poultry that can have a high economic and animal welfare cost, and has become increasingly prevalent in the European Union due to factors such as the removal of antibiotic growth promoters and the requirement to exclude animal by-products from diet formulations. Estimates of the prevalence of necrotic enteritis vary widely (1–40%) as does the cost of the disease, and the subclinical form may be the most important manifestation of the disease as this is likely to go undetected and hence untreated. An outbreak of necrotic enteritis is primarily associated with rapid proliferation of the anaerobic bacterium, Clostridium perfringens type A or C, leading to gaseous extension of the small intestine, the production of one or more exotoxins, and enteric toxicosis. The molecular progression of the disease is quite complex and at the bacterial level involves quorum sensing, toxin production and secretion, and interactions of the pathogen with the innate immune system of the chicken. Intestinal cell permeation by the toxin activates a series of intracellular pathways including protein kinase cascades, and ultimately results in cell death. The precise molecular signals that set off this cascade are still unclear. The various predisposing environmental, health and dietary factors that modify the gut environment and promote colonisation with C. perfringens, are discussed. With such a multi-factorial disease, a working and reproducible experimental model with which to study bacterial/host and dietary/host interactions is an essential tool in the search for appropriate control or management strategies for the poultry industry.

Abstract Red mite (Dermanyssus gallinae; De Geer, 1778) is currently one of the most detrimental ectoparasites in laying birds across several countries. Symptoms of D. gallinae infestation include reduction in production, poor egg quality, increased mortality and also a compromise to welfare. Feeding on its host for only short periods of time, the red mite spends the vast proportion of its short life-cycle hidden deep within the house substructure. For this reason, it is the preference of red mite to occupy free range or barn systems as opposed to caged, since a greater number of potential hiding places can be sought. A problem which will therefore be amplified within the EU with the impending ban on production in laying cages. This, in conjunction with concern over resistance to acaricides, toxicity risks and acaricide withdrawal, make control particularly problematic and financially draining for producers. Therefore alternative methods must be sought, such as vaccine development. However, in order for this to be achieved, an understanding of mite antigenicity must first be established.

Thus, the purpose of this study was to assess immunological response of humeral antibodies to naturally occurring mite antigens, using enzyme-linked immunosorbent assay (ELISA) and SDS-PAGE. Antibodies were derived from egg yolk and blood sera which were collected from commercial laying farms across the UK with varying levels of red mite infestation and using different production systems (caged, barn and free range). In addition, mites were trapped and counted periodically so as to follow population dynamics over a flock lifespan in conjunction with a series of production measures (Laying percentage, eggs per bird per week, mortality and temperature). The results describe the effect of red mite infestation on production parameters, immunological response and the relationship between them.

The microbiological implications of using a small-scale bucket-style washer are reported forchicken eggs. On average, the bucket washerreduced the total bacterial numbers on the surface of eggs under manufacturer-recommended conditions from 5.36 log CFU egg-1 to 2.82 log CFU egg-1. No evidence of enhanced bacterial contamination of the egg contents was found when microbiological examination was undertaken a few hours afterwashing. When washing visibly soiled free-range eggs, there was a tendency forthe wash-waterto become dirty afteronly a few batches of eggs had been washed. Washing in dirty water could increase the numbers of bacteria on the surfaces of those shells which were visibly clean before washing. These additional shell-surface bacteria however, were not detected in the egg contents (n=1032), when analyses were undertaken 1–2 hours after washing. In contrast, when washed eggs were stored for2 weeks at 15°C, we found that bacterial numbers in the egg contents were elevated when compared with unwashed controls. To determine if cool washing temperatures could cause water to taken up by egg contents, eggs were warmed to 37°C, 30°C, 25°C or 20°C and were submerged in aqueous protein stain at 15°C forup to 7 minutes. We did not observe take up of the stain solution unless its temperature was 15°C cooler than the egg contents and the eggs were immersed forat least 3 minutes.

Feeding time has the potential to influence the performance of adult broilerbreeder flocks and is thus of great importance. Aliterature review is presented concerning the responses of adult broilerbreeders to feeding time. It appears that there is no benefit in feeding broiler breeders later in the day with regard to egg numbers oregg weight.

There is a potential improvement in shell quality that results from feeding laterin the day or from splitting the daily feed allocation across more frequent feeding periods throughout the day. However, anticipated improvements in shell quality due to delayed feeding times may not be realised, particularly when birds are housed on litter floors. Furthermore, improvements in shell quality may not be translated into improvements in hatchability due to increases in shell thickness adversely affecting the watervapourconductance of the eggshell.

Broiler hatching egg producers should be aware that later feeding times may delay the time of oviposition, which may demand changes in farm procedures. Furthermore, delayed feeding times may result in feeding activity coinciding with other important periods of activity, such as mating and oviposition, resulting in a reduction in fertility and an increase in the production of eggs with abnormal shells. The current commercial practice of feeding adult broiler breeders early in the day, at, ornear, lights-on, is justified, as feeding at this time has positive consequences for other aspects of hatching egg production. However, afternoon feeding is not necessarily detrimental and may be an option to consider in cases where improvements in shell quality are required, although this may not be the solution for hatchability problems. If a change in feeding time is under consideration, environmental conditions, particularly the photoperiod and ambient temperature, must be taken into account, and any changes should be made gradually, as broiler breeders may be sensitive to abrupt changes in feeding time. Furthermore, changes in the feeding schedule should be accompanied by close monitoring of performance parameters, including the number of settable, abnormal and floor eggs, percentage of fertile eggs, and hatch of fertiles.

When broilers are necessarily subjected to conditions of constant or cycling high temperatures, there is invariably consideration of changing diet formulation. Such changes may involve substitution of specific ingredients and/or alterations to nutrient levels in the diet. Aprimary concern is often the appropriate use of protein-rich ingredients and specifically their content of crude protein and amino acids. Broilers eat less at high temperatures, in an attempt to maintain homeothermy. Logically, diets will be fortified with protein and amino acids to counterbalance reduced intake. It is unclearif amino acids needs are altered, at high environmental temperatures, yet it is clearthat any such change in level orbalance is likely to be of lessermagnitude than change in feed intake. However, there is still controversy as to the direction of change for amino acids and protein under conditions of heat stress. There are specific concerns about the balance of certain amino acids, in particular arginine:lysine and also the source of any synthetic methionine added to correct apparent deficiencies. Balance of amino acids is described relative to pathways for polyamine metabolism.

We review the behavioural needs, priorities and preferences of laying hens for increased space, perching, nesting, foraging and dustbathing behaviour. Hens make full use of and may work to gain access to perches, however it is not yet known how perching ranks in comparison with otherbehaviours. Laying hens appearto have an instinctive need to perform pre-laying (nest-building) behaviour and have a strong preference for a discrete, enclosed nest site, for which they will work hard to gain access as oviposition approaches. Access to a nest site is a high-ranking priority for laying hens, preferred over food at this time. Foraging is a behavioural need, with peat, sand and wood shavings preferred substrates in choice experiments. There is no reduction in time spent foraging when a cost is imposed, nor when feed is freely available. Dustbathing is currently viewed as a behavioural need, as the extent to which hens value dustbathing is not known. Bird preferences for space are complex and confounded by interactions between group size and stocking density. There is some evidence that priority for space varies during the day and increases when the total space available to a group of birds is restricted, and that greater priority is given to space than to small group size. The presence of apparently purposeless behaviour, of high levels of aggression or redirected behaviours such as feather pecking and cannibalism are indicators that the housing system is not meeting the behavioural needs of the hens and hence is not satisfactory forbird welfare.

This paper reviews the contribution that eggs can make to the human diet and considers the additional benefits that can be derived from modifying the egg's nutritional profile and in particular the egg's fats and antioxidants. Attempts to modify the egg's fat component have tended to focus on the means by which the cholesterol level in the egg may be reduced orthe ratio of n-3 to n-6 polyunsaturated fatty acids (PUFAs) manipulated. The cholesterol content of the egg has been lowered by either reducing the mass of the yolk relative to the egg (i.e. a non-specific reduction) or by using feed additives such as beta-cyclodextrin that have a specific effect on the cholesterol content of the yolk. The ratio of n-3:n-6 PUFAs in the diet is important not only because of their role in energy metabolism and biological membranes but because they affect eicosanoid metabolism, gene expression and intercellularcommunication. Eggs produced from hens receiving conventional feeds tend to be relatively high in n-6 PUFAbut dietary manipulation can be used to either increase the amount of the n-3 PUFAs directly (using fish oil) or indirectly by increasing the levels of the precursor n-3 PUFA by feeding alpha-linolenic acid (ALA) in the form of linseeds, flaxseeds or similar. Of particular interest is the n-3 PUFA docosahexaenoic acid (DHA). The relatively high degree of unsaturation makes this PUFAsusceptible to oxidation during storage and cooking but this can be resolved, at least in part, by enriching the egg yolk with antioxidants such as vitamin E. Apart from reducing the rate of PUFAoxidation, enriching the level of antioxidant in the egg can also enhance levels of antioxidants in the consumer. The effect on the consumerof consuming modified and conventional eggs is considered.

An increase in the production of palm kernel meal (PKM) coupled with the concern for continued availability of conventional feedstuffs in some parts of the world has led to research to establish the maximum inclusion level of palm kernel meal in broiler diets. The results suggested that palm kernel meal has no anti-nutritional properties and thus its inclusion is safe up to at least 40% in the diet, provided the diet is balanced in amino acids and metabolisable energy. Although feed digestibility is decreased due to high dietary fibre when PKM is included in the diet, the feed intake is increased. This makes total digestible nutrient intake relatively high. β-mannan is the main component of palm kernel meal non-starch polysaccharide (NSP). Both mannose and manno-oligosaccharides have been reported to act as prebiotics. The inclusion of palm kernel meal in the diet improves the immune system of birds and reduces pathogenic bacteria and increases the population of non-pathogenic bacteria in the intestine. These two benefits should be considered as strong recommendations for using palm kernel meal in broiler diets, particularly in palm kernel meal producing countries, not only forincreasing bird productivity but also to improve chicken health. Selective enzyme addition increases feed efficiency and digestibility as well as decreasing the moisture content of faeces.

Embryonic loss occurring in the first week of the incubation is termed early embryonic mortality. Environmental, technological and genetic factors can be responsible forits appearance. The examination of genetic background of embryonic death is justified when the breeding and hatching technological parameters are optimal. Disposition of early embryonic mortality can be inherited and it can accumulate in a stock, which will finally deteriorate its fertility indices. Although the heritability value of reproductiveness is poor, h2=0.1−0.2, even so, during the selection still should be considered. This paper offers a short review on the special features of early embryonic development in poultry and examination methods forpossible genetic background of early embryonic abnormalities and mortality. The application of cytogenetical and embryological methods may be of major relevance in the improvement of the reproduction traits of poultry species.

One of the environmental challenges that the poultry industry has been faced with is manure utilization or disposal. Poultry manure and its nitrogenous compounds can be a potential pollutant causing eutrophication, nitrate or nitrite contamination of water, ammonia volatilization, and acid deposition in the air. Therefore, reducing nitrogen excretion and emissions in poultry manure is important to maintain a clean environment. Proper nutrition is an important first step to optimize performance and growth in animals as well as to reduce the negative impacts on the environment. Amino acids are components of protein nutrition that greatly influence growth and one of the essential amino acids is methionine, which is often first limiting amino acid in high protein diets for poultry. However, excess or insufficient methionine supplementation into diets increases nitrogen excretion and emissions to the environment. One way to reduce nitrogen excretion and emissions is reducing crude protein level and supplementing analogues of amino acids to meet the amino acid requirements. Several analogue forms of methionine are commercially available as economic alternatives for the animals now. Supplementation of hydroxy analogues into low protein diets can minimize excess amino nitrogen in the diets and reduce nitrogen excretion. In order to use these dietary strategies effectively, a well-balanced feed formulation and a precise way of rapidly quantitating the bioavailable sulphur amino acid in feeds remains to be developed.

A short review is given of the beginnings of an organised poultry production in the Republic of Croatia, along with the changes that came about during the transition period, from the year 1993 to 2003. That analysis includes basic characteristics of the Croatian poultry products market, such as poultry production facilities and the number of birds, the production and consumption of poultry meat and hen eggs as well as the export and import of poultry products. The result shows that Croatian poultry production is organised in 498 enterprises and 346,530 family farms. In the period examined, Croatia produced on the average 86.2 thousand tons of poultry weight gain and 825 million eggs (49.5 thousand tons). In 2003 – 19.3 kg of poultry meat and 8.1 kg of eggs were consumed per household member. The overall foreign trade balance of Croatian poultry product was positive over the entire research period.