Well winter is certainly with us in New Zealand with rain and wind, but it seems that other parts of the world aren’t having the summer they were expecting. As a nutritionist, feed materials are a main interest of mine, and yet again it seems that harvests are likely to be poor this year, making it difficult to farm in an economic fashion. The conference season is well under way at the time of writing, and although most people are gearing up for the WPC next year in Brazil, there are still some interesting events regarding poultry. The Board is holding its meeting at the Turkey conference at the end of October/start November and I would like to thank the organisers there for hosting us. It should be an enjoyable place to work for a few days.

In this issue you will see that we have a variety of papers, and it’s very encouraging that more authors from different scientific spheres are using the WPSJ to publish their reviews. We are getting more INFPD papers coming in as well – which is important as encouraging poultry production in developing countries is a key tenet of the Association. Of course, it’s impossible to control what gets submitted from my point of view – but variety in topics is so good for our readership that I would like to encourage anyone who is ‘doing something different’ to consider putting in a review online. On that topic – we still have some problems with authors not taking on board the fact that we only publish review papers not single experiments. The instructions for our content and formatting are very clear – so please read them is you are an author. Please do not submit single experiment s to me as this costs us money that we have to charge to the authors.

In June I will get the latest ratings for the journal – the quality standard all journals are subjected to on an annual basis which gives an indication of how important we are in the field of agricultural science. Current we are at tenth place in our category which is excellent for a small journal that is only published quarterly. So keep the papers coming and I hope you all find something of interest in this issue.

Dr Lucy Waldron

Editor

Understanding the metabolism of lipoproteins in birds is important to enable nutritionists to design diets aimed at obtaining better meat characteristics and egg quality, and can furnish useful information for future studies. In comparison to mammals, there are a number of expressive differences in the metabolism of lipids in birds, such as the transport of dietary lipids to the liver, hepatic lipogenesis and the presence of unique lipoproteins in the blood (portomicrons). Greater differences are found in egg-laying hens during the production phase, in which lipoproteins produced in the liver, under the action of oestrogen, are used for the formation of the egg yolk. The regulation of the lipid metabolism by hormones and the participation of key enzymes associated to advances in molecular biology techniques could assist in the genetic selection of more productive birds and better quality products for consumers.

Poultry production has been identified as a major producer of NH3 and, to a lesser extent, of greenhouse gases (GHGs) mainly by national emissions inventories. However, since most national inventories are based on average emission factors for each type of animal (‘tier 1’ approach), the factors that influence these emissions (through breeding and manure-management practices) are not taken into account. The first step to improve inventories and propose mitigation options (e.g. best management practices, innovative systems) is a better understanding of the drivers of gaseous emissions and the identification of key factors for the mitigation of NH3 and GHG emissions. This paper presents a literature review of NH3 and GHG emissions from poultry housing, with a focus on the influence of practices and rearing conditions. It appears that flock-management practices (e.g. dietary practices, slaughtering age) and manure management (e.g. manure removal frequency, chemical treatment of litter) are presented as efficient ways to reduce emissions. Environmental conditions (e.g. ventilation rates, temperature) influence emissions; however, it was not possible to assess the effects of different combinations of these factors (compensatory or synergistic). Some factors, such as stocking density, which may play a significant role, were not studied. Modelling approaches that integrate these key factors with climate factors can be used to update emission factors in emissions inventories, consider national variability and uncertainties in mitigation scenarios, test synergistic and compensatory effects and avoid pollution swapping. Further research must be carried out to check the validity of emission factors and modelling parameters at a national scale.

Excessive specialisation and production requirements place high demands on the metabolism of the broiler chicken. A number of metabolic problems, such as ascites, arise in chickens due to intensive selection to manifest their genetic potential for rapid growth. Ascites syndrome (Pulmonary Hypertension Syndrome) is one of the major causes of mortality and morbidity in modern broiler production today. Genetics, the environment, and management all seem to interact to produce a cascade of events that culminate in ascites syndrome. It is generally accepted that the high metabolic rate of current broiler lines causes an increased demand for oxygen, especially in cold environments or when birds are fed high nutrient density diets. In such situations, the relatively underdeveloped cardio-respiratory system of modern broilers fails to fulfil the required oxygen demand, which leads to hypoxemia, resulting in the development of pulmonary hypertension and subsequently ascites. Many nutritional, medicinal and management strategies have been proposed to alleviate the ascites. Higher levels of dietary vitamin C and E along with selenium might be beneficial, as they decrease the free radicals that are generated in birds with ascites. As the high metabolic rate (fast growth) is a major factor contributing to the susceptibility of broilers to ascites, appropriate selection strategies or feed restriction or light restriction in order to slow down the growth rate seem practically viable methods, since final body weight is not compromised. Optimisation of the house temperature and ventilation in cold weather seem helpful practices to decrease the incidence of ascites.

Heat stress is associated with compromised performance and productivity in poultry due to declines in feed intake, nutrient utilisation, growth rate, egg production and quality, feed efficiency and immunity. Additionally, heat stress is characterised by reduced antioxidant status in birds, resulting in increased oxidative stress. Heat stress is also linked with increased economic losses due to mortality of birds. Vitamin E is a major chain-breaking antioxidant in biological systems. An optimum response with supplementation of vitamin E in feed has been found to improve feed intake, body weight gain, feed efficiency, egg production and quality, nutrient digestibility, immune response and antioxidant status in poultry birds. This work compiles past and present information about the role of vitamin E in heat-stressed poultry.

This review focuses on a selected micro mineral, where the highlight is its role in meat quality. Minerals are important for optimising livestock and poultry performance. Initial symptoms of mineral imbalances, subclinical inadequacies, or severe deficiencies include depressed growth, body weight gain, poor feed utilisation efficiency, and reproductive efficiency. Dietary trace elements, particularly selenium, are able to induce physiological changes in muscle tissue, and they can alter meat quality in livestock and poultry. Bearing in mind the role of selenium in the quality of meat produced, the limited research into the association of selenium and skin health has been included in the review.

Mycotoxins are secondary metabolites produced by fungi. Mycotoxins in feed are considered the second most serious issue in the poultry industry, following increased feed prices. There are different types of mycotoxins, including aflatoxins, ochratoxins, fumonisin, trichothecenes, zearalenone, patulin, but the most important are aflatoxins and ochratoxins. Ochratoxin is known as a nephrotoxin as it damages kidney tissues predominantly, whereas aflatoxin has more adverse effects upon the liver. Diagnosis and determination of toxins can be done in tissues and feed samples by using different techniques such as high performance liquid chromatography (HPLC), thin layer liquid chromatography (TLC), and fluorescence polarization immunoassay (FPIA). Treatment of mycotoxicosis can be done by decontamination or detoxification of feed by using mycotoxin binders, plant preparations (nutraceuticals) and vitamins. Mycotoxicosis can be controlled by using transgenic crops and improving harvesting management, storing feed in good environmental conditions and fresh feed for the birds. Hazard analysis critical control point (HACCP) should be referred to for the control of mycotoxins in the food chain.

Moulting is a complex process, induced by diet manipulation, which results in renewal of reproductive system and subsequent better production. Conventionally, moulting has been practised by utilising feed withdrawal in many developing countries, however, this has been associated with many drawbacks. Alternative types of moulting practices have been studied, however, these are not practised widely due to a range of undesirable effects. As a consequence of the beneficial effects on laying hens, better post-moult performance and a less criticised method according to poultry welfare advocates, Zn-induced moulting has been considered superior to forced-moulting. Different aspects of Zn-induced moulting related to physiology and production, with special reference to immunohistochemistry of pituitary gland as affected by Zn-induce moulting are included in this review.

The rearing of indigenous chickens is an integral part of the smallholder farming system in the tropics, where they are kept by the rural poor to fulfil multiple functions. Their special adaptation to environmental stresses and poor husbandry practices has made them the choice of breed for smallholder production systems. However, little effort has been made to characterise the indigenous chicken and their production environment, despite the increase in emerging works recently. This paper aims at reviewing the current state of phenotypic characterisation work on indigenous chickens in the tropics. By and large, studies conducted on indigenous chickens to evaluate their performance usually ignore their unique physiological and behavioural characteristics and their socio-cultural values. Moreover, unfair comparisons with exotic chickens are not uncommon, especially for yield related traits. Due to their high genetic diversity, there is also remarkable variation in the performance of indigenous chickens within and among breeds. This variation is an important genetic attribute of the indigenous chicken, whereby selection can act to improve their performance. It is recommended that characterisation works use a common set of descriptions developed by international institutions with proven poultry experience so results across countries and regions can be accurately compared.

The study was carried out by the Department of Dakoro in Niger, where the main characteristics of small-scale family poultry farms were described. One hundred and forty seven farms were surveyed between November 2007 and February 2008 and 15 others were further added. In 78% of the farms, men were in charge of the poultry flocks. The main species raised were chickens (78%) and guinea fowls (18%). A representative flock had 43 hens and ten guinea fowls and would include a rooster, six hens and 35 young (two females and 22 guinea fowl keets). Millet grains and/or bran were used as feed materials by 99% of farmers for their poultry. Chicks and guinea fowl keets received starter feeds based on local products in 78% and 76% of farms, respectively. In 138 farms, drinking water from wells and boreholes was distributed. Sexual maturity was reached at approximately 24 to 25 weeks of age for roosters and hens and 32 weeks for guinea fowls. Hens laid an average of 55 eggs (97 for guinea fowl) in 4.4 clutches of 12 each. Hatchability fluctuated between 81% and 93% and reported mortality rate was as high as 33%. Rudimentary poultry houses based on stem grass were reported in 117 farms. One hundred and forty five farms had clay bell-shaped drinkers and recycled utensils were used as feeders in 120 farms. Poultry veterinary products were used in 25% of the farms surveyed, along with human medicines (21%) and traditional pharmacopoeias (16%). The major causes of mortality were undiagnosed diseases (72%), poor housing (13%), predation (8%) and lack of feed (6%). Own consumption (46%) was the main destination for poultry products followed by sales (43%) and donations (11%). Increasing awareness among farmers to aid in better management of their flocks and the promotion of the production and consumption of poultry products, characterization and better utilisation of available feed resources and more adequate housing were proposed to improve family-based poultry farming.

The World’s Poultry Science Journal is indebted to Prof J.A. Castello, Prof D.K. Flock, Dr D. Grastilleur, Dr S. Cherepanov and Prof N. Yang for the translations of these summaries.