In chickens, metabolism is influenced by environmental factors and of particular interest nutritional factors, such as diet quantity and composition. With respect to the dietary macronutrients, literature clearly shows that in isoenergetically formulated diets, the protein level has a pronounced effect on metabolism, whereas fat and carbohydrate concentrations play a limited role. A decreased dietary protein level results in depressed growth rates, with reduced carcass gains in both water and protein content. In spite of the lower protein retention in chickens fed low protein diets, the efficiency of utilization of dietary protein appears to be increased. This indicates an inverse relationship between protein intake and utilization, which is reflected in decreased circulating uric acid levels. In addition, feed intake is increased, at least when protein levels are slightly reduced, leading to an involuntary overconsumption of energy compared to protein. The chickens deal with this excess energy consumption by increasing de novo lipogenesis and fat deposition, which is supported by increased plasma triglyceride concentrations, and heat production is increased. In contrast to adult mammals, the dietary macronutrients have no effect on diet-induced thermogenesis, nor is there any relationship between diet-induced thermogenesis and feed intake. Plasma growth hormone levels are higher in chickens reared on a low protein diet, indicating a causal relationship between growth hormone secretion and protein efficiency. In spite of the increased growth hormone levels, plasma insulin-like growth factor concentrations are lowered in low protein reared chickens, and may be partially responsible for the reduced growth rate observed in these animals. Plasma corticosterone concentrations are augmented in chickens on low protein diets, despite a decline in the ACTH concentration. Finally, plasma T3 and T4 levels are well known to increase and decrease, respectively, with decreasing protein content, whereas the effects of dietary macronutrients on circulating leptin levels require more research.

European agriculture – its economic significance, its social status, its political weight, its technological level – has undergone considerable changes over the past decades. Indeed, these changes will also continue in the coming years. Accordingly, the knowledge, expertise and education base underpinning agriculture as an industrial and societal activity has to follow these changes by adapting its science base, its priorities, its organization and its way of operation. This paper seeks to present a bird's eye view of the developments in European agricultural research and education structure and will try to formulate the paradigms of a new concept of the notion ‘agricultural knowledge and expertise base’: As from the end of World War II the European industry and society developed gradually from a more or less regulated situation into a virtually completely open industrial market and civil society. And within that context, the agri-food industry developed from a mainstay of European economy into just one stakeholder in a whole complex of rural economy. Accordingly the agricultural research and education and knowledge system is developing from a homogeneous, oligo-disciplinary, institutional and monopolistic system into a heterogeneous, poly-disciplinary and virtual system.

During the past four decades, research efforts directed toward reducing shell egg cholesterol content have centred on genetic selection or alteration of the laying hens' diet with various nutrients, natural products, non-nutritive factors, or pharmacological agents. However, the vast majority of these experimental approaches elicited only minimal changes (<10%) at best or, as in the case of dietary azasterols and triparanol, resulted in the unacceptable replacement of yolk cholesterol by desmosterol. In contrast, when 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (‘statins’), garlic paste, or pharmacological amounts of copper were orally administered to chickens, yolk cholesterol levels were reduced by up to 46%, 32%, or 34%, respectively. The previous paper in this two-part series provided a justification for low-cholesterol egg production and reviewed cholesterol metabolism in the laying hen, avian embryonic cholesterol needs, and genetic and nutritional approaches to chicken egg cholesterol reduction. The present paper provides a comprehensive overview of the use of non-nutritive dietary factors and select pharmacological compounds as egg cholesterol-lowering agents, and discusses emerging strategies for lowering the cholesterol content of shell eggs. With the recent advances in avian genomics and transgenesis, it is anticipated that the greatest advances in the area of yolk cholesterol reduction will be attained through manipulation of key genes whose protein products mediate intestinal sterol absorption, hepatic cholesterol and lipoprotein synthesis, and/or lipoprotein uptake by growing oocytes. However, the future commercial availability of low-cholesterol eggs produced by transgenic hens ultimately will be influenced by the nature of the regulatory environment for bioengineered foods, public acceptance, and economics.

Ethanol production started in the late 1970s in Brazil and some years later in the USA. In contrast to these two countries, EU member states concentrated on biodiesel production because of lower diesel prices and the constantly increasing number of diesel-engine-driven cars. After several years of moderate growth rates, biofuel production began to increase rapidly. This resulted in an increasing demand for arable land on which corn and oilcrops are cultivated for ethanol refineries and biodiesel plants. Perspectives of future biofuel production in the USA, the EU, Brazil, China, India, and several other countries in Southeast Asia show that the demand for arable land will further increase. This will not only lead to higher feed costs for the livestock and poultry industry but also to higher food costs. At the present moment, bio-energy production is not yet a threat to the egg industry, but it can be expected that the recent scenarios of a possible climate change until the end of this century will lead to a fast expansion of the bio-energy industry.

Semen cryopreservation in domestic birds has been studied extensively in the past fifty years. However, efficient methods to freeze semen of chicken of different breeds have emerged only in the last decade of the 20th century. Methods using the cryoprotectants glycerol, dimethyl acetamide and dimethyl sulfoxide, slow or rapid freezing-thawing procedures, pellets or vials or straws packaging have been developed. Other methods have been studied in turkeys, guinea fowl, ducks, ganders and some wild species. They are often less successful than chicken freezing methods with wide intra-species variability.

Reliable predictors of suitability of semen for cryopreservation are also needed to improve freezing methods and to optimize the management of frozen semen. The quality of whole fresh semen measured by classical morphologic, metabolic and mobility tests is an indicator. More specialized tests such as membrane fluidity of fresh spermatozoa are indicative of the freezing ability of the gametes.

The main use of semen cryopreservation in birds is the ex situ management of genetic resources in the context of dramatic decrease in avian genetic biodiversity. This is achieved through germplasm cryobanks. There are three main national avian germplasm cryobank programmes in 2006, operating in North America, The Netherlands and France. They mainly include semen and blood samples issued from Public Research Lines, indigenous breeds and individual specific genotypes.

The future need for semen cryopreservation programmes will focus mainly on three objectives 1) improvement of predictors of male suitability for semen freezing, 2) emergence of standardized methods of semen freezing in species other than chicken and 3) increasing development of avian cryobanks.

China has an abundant and a wide variety of goose resources. The systemic estimation of genetic diversity of Chinese indigenous geese will provide an important scientific basis for the conservation and utilization of the resource. Twenty-six Chinese native goose populations were studied to estimate genetic diversity and genetic structure using 31-microsatellite markers. The genetic relationships between populations were analyzed in combination with their geographic distribution and origin of these breeds. According to the allele frequencies of 31-microsatellite loci, polymorphic information content (PIC), average heterozygosity (H) and DA genetic distances were calculated. Twenty-nine of the 31 microsatellite loci were medium or high polymorphism, so the 29 microsatellite markers were effective markers for analysis of genetic relationship among goose breeds. The average expected heterozygosity (HE) was between 0.501 and 0.705, the numeric order of which was consistent with that of PIC, and which reflected the strong genetic potential and strong adaptability. The topology of phylogenetic tree constructed from a Neighbour- Joining method based on DA genetic distances, showed general patterns of relationship and genetic structure among the populations studied. Topology analysis revealed that the twenty-six Chinese populations were divided into five groups and that the genetic relationships among the populations had obvious association with their historical relations and geographical distribution.

Embryonic development is a dynamic process that requires a fine balance between several factors in order to achieve an optimum hatchability and chick quality. These factors include the background of the embryo, such as genetic line of the breeders, the age of the breeder, egg weight, and factors related to the environment in which the egg is stored and incubated, such as temperature, humidity, gas levels and altitude. Gas exchanges are of fundamental importance for embryonic development during incubation and may affect the livability of the embryo. This paper reviews the roles of the gaseous environment (i.e. O2 and CO2) around hatching eggs during storage and during incubation and the effect it might have on the survival of the developing embryos and the chicks that hatch. The state of the art on the different attempts to establish the optimum requirements of different gases that promote the optimal developmental trajectories at different periods during incubation is presented. The roles and consequences of different levels of O2 and CO2 during storage and incubation on hatchability, incubation duration, hatching process, embryo growth, embryo mortality, organ development and morphology, metabolism, blood acid-base balance, chick quality and chick post-hatch growth are reviewed.

Three main aspects of chicken biodiversity are dealt within this report: (a) cluster analysis based on autosomal microsatellites, (b) microsatellites on the sex chromosomes, and (c) SNP-based biodiversity.

(a) Cluster analysis of autosomal microsatellites: We used 29 microsatellites to genotype 2000 chickens randomly selected from 65 different populations representing various chicken types and various geographical regions. The computer program Structure placed the 65 populations into clusters that are in agreement with their geographic origin and breed history. Only at two predefined clusters, there is little admixture between non-commercial populations originating from Asia and those from Europe. In contrast, commercial broilers and brown egg layers appeared as admixed populations of these two main gene pools. Increasing the number of clusters resulted in generation of specific clusters of commercial lines, having very low admixture with other clusters. In addition, we identified seven mixed populations, each of which shared portions of their genome with several other genetic clusters.

(b) Microsatellites on the sex chromosomes: We predicted 173 potential microsatellites on chromosome W by in-silico analysis of the chicken genome assembly (version WASHUC1). Twenty five microsatellites of the highest sequence quality were tested in the lab for gender specificity. Unexpectedly, PCR products were generated in both sexes. Moreover, 14 selected microsatellites were mapped (using the East Lansing reference panel) and in all cases, the “W specific” microsatellites were mapped to chromosome Z and except for one locus, to the same ∼6 cM region. We conclude that the draft assembly for chromosome W is quite inaccurate.

(c) SNP-based biodiversity: Ten distinct chicken breeds were genotyped at 145 single nucleotide polymorphisms (SNPs) located at 14 random DNA fragments and twenty five, each from different and unlinked genes. Microsatellite genotypes of the same ten breeds were used for comparison. Applying bootstrap values as the criterion for tree's reliability, we found that: (1) increasing the number of SNPs had a higher impact on the reliability of the analysis than increasing the number of individuals per population, and (2) the bootstrap values of phylogenetic un-rooted trees based on microsatellites were relatively low.

A well-designed environmental control system is the most efficient tool to ensure optimal production in livestock housing. In countries having a hot climate, such as Spain, the former comprises a large proportion of the capital invested in housing, and it deserves a thorough assessment. Most of the research carried out has been done in countries with a temperate climate and considering short hot periods, or even without them. The efficiency of the evaporative cooling system, which is commonly used in hot climate areas, depends upon the pad wetted surface area exposed to the passing air. Keeping the chosen inside temperature requires a definite cooled down of the outdoor air that is related to the ‘temperature tolerance’, i.e. the difference between inside and incoming air temperatures. The objective of this work was to establish the temperature tolerance when using the steady-state heat balance in commercial poultry housing. The heat balance estimates were imbalanced whenever the difference between indoor and outdoor temperature was less than 2°C. Substituting the exhaust air temperature for the indoor temperature in the expression that provides the heat drawn out through ventilation balanced the heat equation. The difference between inside and incoming air temperatures, temperature tolerance, has to be at least 2°C.

The global poultry industry is undergoing many changes, one being the need for efficient disposal of its broiler litter (BL) due to a reduction in the land available for cost effective disposal. To date, Australian BL disposal has been achieved by selling the litter as a fertiliser to agricultural sectors. Research indicates BL and other poultry industry waste streams could be used as a food source for vermiculture systems, allowing the sale of vermi-cast as a biologically enhanced fertiliser and worms for protein. If this approach is economically viable then the poultry industry could reduce its environmental impact and operate more like a closed loop system. Integrated bio-systems using vermiculture, composting and waste-to-energy technologies have developed significantly overseas and have shown potential to solve many of the issues associated with poultry waste disposal.

Throughout the African continent the keeping of poultry by local communities has been practised for many generations. These birds currently make up more than 80% of the continent's poultry flock. Family poultry (FP) is a valuable asset to local human populations as it contributes significantly to their livelihoods and overall well-being, especially in disadvantaged groups and less-favoured areas of Africa. In many households, poultry are managed by women, children and vulnerable people (e.g. old and disable persons). The recent outbreaks of the highly pathogenic avian influenza (HPAI) in Africa are of major concern. The paper stresses the multiple roles of poultry at household, community and national levels. The impact of HPAI on FP production is also explored.

The purpose of the research was to identify measurable indicators, which can firstly provide objective measures of bird welfare and secondly act as ”lead” rather than “lag” indicators. Broiler welfare has historically been measured using lag indicators such as final mortality, stocking density, levels of contact dermatitis, reject levels and leg health. Although there are benefits to their use as indicators, the main disadvantage of these measures is that whilst they provide data for interorganisational and inter-growing cycle analysis the welfare issues have already occurred for the birds concerned and the information can only effect change in future production cycles. Alternatively, lead indicators are intra-cycle indicators which will provide information on bird welfare so that preventive/corrective action can be taken within the growing cycle. These indicators include feed and water consumption, air and litter quality and daily weight gain. It has been established that water is a vital nutrient that should be routinely analysed to ensure that it complies with accepted quality standards so that bird health and welfare is optimised. Furthermore water consumption, (both daily and per cycle) is a key indicator of bird welfare and worthy of further quantitative study to determine if it can be used as a headline “lead” indicator to determine health and welfare issues early in the growing cycle so that appropriate management action can be taken.

The aim of the study was to analyse water consumption data of commercially grown broiler chicken in order to ascertain whether:

1. i) the results obtained correlated with those reported in other studies;

2. ii) water consumption can be objectively used as a measure of bird health and welfare; and

3. iii) there is a correlation between total water consumed, reject levels and the incidence of contact dermatitis.

Food safety and shelf-life are both important microbial concerns in relation to broiler meat production. Focus is mainly placed on the absence or control of potentially pathogenic microbes such as Salmonella and Campylobacter but, from commercial point of view, other spoilage bacteria also play a role. Regarding food safety, the primary target should be the production of pathogen-free live animals, thereby allowing slaughter plants to keep the processing line free of those micro-organisms. Pathogen-free feed is fundamental in obtaining such conditions, as is the Good Hygienic Practice in farming, including grand parent stock (GPS), parent stock (PS) and hatcheries.

Interventions in the slaughter plant cannot always completely remove pathogens. However there are some measures of control available, including separation of flocks, carcass decontamination and implementing a balanced and operational HACCP system.

Shelf-life is closely linked to food safety during processing. The developments towards in-line processing, including chilling, portioning and deboning, allows optimal control. It minimizes processing time and product to product contact, and thus increases shelf-life and limits cross contamination. Refrigeration conditions are very important and an interruption of the refrigeration chain can accelerate microbial growth. Modified atmosphere packaging (MAP) may contribute in controlling the undesired growth of spoilage organisms, and can play a role in food safety as well.

The consumer needs to be educated in how to deal with food of animal origin that cannot be produced in an entirely sterile environment, in order to ensure shelf-life and correct preparation and use.

Wheat is a common ingredient in poultry diets, especially in Europe. Due to its low protein and high starch levels, wheat is essentially used as an energy supplier. Nutritional values of wheat samples vary according to their nutrient content and digestibilities. Variations of nutrient contents may be associated with cultivars and environmental conditions. Digestibility variations in growing chicks may be associated with these factors, and also, with technological treatments of diets and genetic origin of birds.

Total nutrient content (starch, protein, lipids and sugars) is strongly related to fibre content through a negative relationship. A large part of fibre content variations of wheat samples depends on their cultivar origin. Wheat protein content depends both on cultivar and environmental conditions. High yield cultivars are often associated with low protein content.

Lipid and starch digestibilities of wheat diets given to growing birds may sometimes be rather low.

The main reason of the low lipid digestibility values observed with some wheat samples is the high viscosity of water-extract induced by their water-soluble arabinoxylans. This viscosity results from a combination of several variables including the potential applied viscosity value (PAV as mL/g) of the wheat cultivar, the endogenous and exogenous xylanases, and the endogenous anti-xylanase contents. Environmental conditions and technological treatments are major factors acting on xylanase and anti-xylanase contents.

A part of wheat starch digestibility variations may be related to accessibility problems in coarse particles due to hard wheat cultivars and coarse grinding. However, coarse particles may be positive for stimulating feed intake of mash diets, and protecting against intestinal transit disorders.

In growing chicks, genetic origin of birds may result in very large variations in the digestibility of wheat diets, as observed with the divergent D+ and D− “Digestion” lines selected on the digestion ability of a wheat diet. In 3 w old chickens selected over 4 generations, the AMEn value of a Rialto wheat diet was 13% lower in D− than in D+birds (P=0.0001). D− birds showed 10% variations in AMEn values between four cereal diets (P=0.0003), while D+ birds showed only 4% variations (P=0.0006). In D+ birds, AMEn values of wheat and maize diets were the same (14,488 vs. 14,538 J/g DM), while, in D− birds, AMEn values of wheat diets were 5% lower (P=0.015) than the maize diet value (13,106 vs. 13,809 J/g DM).

The neuroendocrine systems, such as dopamine (DA) and serotonin (5-HT) as well as corticosterone (CORT), are involved in regulating behavioural patterns and reproduction in humans and other mammals. Similar functions of neuroendocrine system may present in laying hens. To test the hypothesis, two divergent chicken lines were used in the study. Each line has distinct levels of aggressiveness and productivity at a group setting and exhibits differen susceptibility to various environmental stressors. We found that, at 21 wks of age, LGPS (Low Group Productivity and Survivability) birds had significantly higher blood concentrations of DA and epinephrine than the KGB birds (Kind Gentle Birds, also previously termed HGPS, birds with a High Group Productivity and Survivability) (P<0.01, respectively). The blood concentration of norepinephrine was not significantly different between the lines but the ratio of epinephrine to norepinephrine was higher in LGPS birds (P<0.01). The blood concentration of 5-HT was also significantly higher in LGPS birds compared to KGB birds (P<0.01). In contrast, KGB birds tended to have a higher level of blood CORT (P=0.1). The results suggest that genetic selection for productivity and survivability with domestic behaviours alters the birds' neuroendocrine homeostasis. The selection-associated plasticity of the neuroendocrine system in controlling animal aggression and productivity were discussed in the article.

In this paper we analyse virtual learning environments to provide a framework for developing a set of quality indicators for an e-learning course in the domain of poultry welfare, environment and food quality interactions. The framework is based on a case study: an e-learning course which is developed in the context of the Leonardo da Vinci Community Vocational Training Action Pilot Project entitled “WELFOOD-Promoting quality assurance in animal welfare-environment-food quality interaction studies through upgraded e-learning”. First, general issues and known questions regarding Quality Assurance (QA) for Open Distance Learning are examined. Secondly, the domain specific needs for e-learning based education are studied in relation to the target groups/sectors addressed (education, agriculture, food industry). The framework also takes into consideration the fact that such a course is developed and should be offered and tested for its educational value, collaboratively by the project partners. Finally, the course is made available in the national language of each participating institute, so that the possibility for access to expertise and the opportunity for continuous training is guaranteed.

High ambient temperature could result in numerous physiological and metabolic changes in broilers, that adversely impact broiler performance and immune response. In addition to environmental control techniques that have been frequently used to reduce the negative impact of heat stress on birds' performance, other measures have been studied. Lately, proper nutritional management has shown to be effect as a preventive measure against heat stress because the function of the thermoregulating system of broilers (heat production, evaporative and nonevaporative routes for heat dissipation) can be influenced by diet. This applies particularly to the establishment of proper electrolyte balances due to their physiological importance in the heat stress mechanism. Thus, nutritional mechanisms should be reassessed as a tool to control this metabolic dysfunction in birds.

There has been little work conducted over the last 40 years on estimating vitamin requirements of poultry, and so consequently NRC (1994) values are still often quoted as standards. A review of this information indicates many values are estimates, or extrapolated from comparable species, or as with broiler breeders, simply not given. The current concern related to formulating vitamin levels in poultry diets is the assumption that change in genetic potential of layers and meat birds necessitates re-evaluation, and that parameters for assessing needs are now more complex than simple production metrics as used previously. Unfortunately information on maintenance needs for vitamins is lacking, and while there is now information available on vitamin content of eggs, comprehensive details of the vitamin level in poultry meat products is surprising lacking. With unprecedented egg output of modern layer strains, and ever improving feed efficiency in meat birds, vitamin intake per unit of output is continually declining. For layers the estimate is around a 1% yearly decline in vitamin intake per egg produced, while for meat birds there has been a 0.6-0.8% yearly decline per kg body gain. This reduced intake of vitamins is the basis for improved performance in layers and meat birds fed a higher than normal level of vitamins. However, an even more important basis for reevaluating vitamin needs is change in measurement criteria. Many vitamins and especially the fat soluble vitamins accumulate in eggs and meat in proportion to diet inclusion. Development of vitamin enriched designer poultry products therefore dictates elevated feeding levels of vitamins. Co-incidentally, increased levels of vitamin E in poultry products has led to the realization that increased antioxidant capacity of these tissues enhances shelf life and appearance. Of greatest impact in reevaluating diet vitamin specifications has been the effect of these nutrients on bird health and in particular immune response. For example dietary levels of vitamin E far in excess of NRC (1994) requirements have been shown to positively impact immune response in all ages of bird and also the performance of heat-stressed birds. Expectations of ever increasing performance dictate the need for continual reevaluation in determining vitamin levels within diet formulations as detailed in recent publications on optimum vitamin nutrition of poultry to improve health, welfare, performance and the quality of poultry products.

Chicken is one of the most important sources of animal protein for human consumption, and breeding programmes have been responsible for constant improvements in production efficiency and product quality. Furthermore, chicken has largely contributed to fundamental discoveries in biology for the last 100 years. In this article we review recent developments in poultry genomics and their contribution to adding functional information to the already existing structural genomics, including the availability of the complete genome sequence, a comprehensive collection of mRNA sequences (ESTs), microarray platforms, and their use to complement QTL mapping strategies in the identification of genes that underlie complex traits. Efforts of the Brazilian Poultry Genomics Programme in this area resulted in generation of a resource population, which was used for identification of Quantitative Trait Loci (QTL) regions, generation of ESTs and candidate gene studies that contributed to furthering our understanding of the complex biological processes involved in growth and muscular development in chicken.