The first issue of the year and already we have finalised the June issue with the amount of papers coming in. In this issue we have papers on lighting, uniformity of flocks, trace minerals as well as specialist and novel ingredients. This year sees the preparation of the 2020 WPC in Paris kicking off, which looks to be an excellent programme and all-round experience, both academic and commercial. Issue around the world are increasingly focussed on the limitation or removal of antibiotics in those countries that have not yet done so, and hence the increasing importance of biosecurity on farm for maintaining poultry health and welfare. The industry globally has had to adapt to many changes in regulations and many countries have already gone a long way in their examination of more consumer acceptable alternatives to traditional prophylactic measures – which should make it easier for those regions making the transition now or in the near future. My invitations to speak at various conferences and workshops in China last year where they are bringing in restrictions on growth promoters in feed has highlighted this well, as they come into line with the rest of the world in terms of what retailers and consumers require in poultry production as well as controlling pollution from excretion. Registering alternatives to growth promoters, e.g. plant extracts, will require new regulatory processes in various countries.

This year sees several major conferences being hosted, including the fabulous Hafez turkey diseases meeting in May, which I can highly recommend, especially the conference dinner and belly dancers. September sees the 25th European Poultry Conference, being held in Croatia, which is also the venue for the global board meeting – and I will be hosting the editorial meeting there as well and hope to catch up with colleagues and friends. Other commercial and regional meetings are already listed on the WPSA website – please check it out and attend as much as you can to support regional branches and the larger meetings, as the organisers put a lot of effort and time into staging these events.

The editorial office would like to wish all readers and members and happy (if belated) and prosperous 2018 and look forward to seeing you at meetings. Keep the papers coming!

Dr Lucy Waldron

Editor

Macroscopic algae can be found in large open ponds or harvested from the sea. Macro algae includes three distinct groups based on colour: green, brown and red. They are unique in containing secondary metabolites that can be extracted and used for various purposes. This review examines the antimicrobial properties (bacteria, viruses and fungi) of macro algae and its extracts to improve poultry health and performance. This includes body weight gain, feed conversion efficiency and carcass yield improvements in broilers and egg weight and shell quality in layers. As an example, in one study, 35-day body weight of broilers was increased 7.6% with the inclusion of 0.5% Undaria pinnatifida (brown macroalgae) to the diet. The investigations discussed show the diversity of the species available and broad scope where research has been done and the potential for the future.

Poor uniformity in a broiler operation reduces revenue and increases waste. Uniformity in body weight at harvest is influenced by variation in genotype, environment and feed composition and form. Variation in growth in broilers within each sex is usually relatively small, but increases markedly when a poor quality feed is given. In attempting to grow to meet their potential when fed a diet low in protein, birds need to overconsume energy and then release excessive amounts of heat to the environment, although this ability is constrained by both feather cover and the ability to fatten. Consequently, as broiler genotypes have become faster growing and leaner, there is an increased need to feed higher levels of balanced protein in a cooler environment as a means of improving uniformity. Separating the sexes and reducing the range in day-old body weights will assist in achieving better uniformity at harvest.

In birds, after natural mating or artificial insemination (AI), sperms are transported through cloaca or vagina at the utero-vaginal junction (UVJ) of oviduct. Only 1% of the deposited sperm passes through the selection process in the vagina to reach the UVJ. In the UVJ, sperm enter the tubular invagination of the surface epithelium of the mucosa collectively called ‘sperm storage tubules’ (SSTs) where they are stored for longer duration retaining their fertilising capacity. The storage capacity and duration varies from species to species. This enables the birds to produce fertile eggs continuously. Shortly before and during egg production, sperm residing in the SST upon release will ascend the oviduct to the site of fertilisation in the infundibulum. Within the SSTs, sperm motility is suppressed and is initiated at some stage before fertilisation. Restoration of sperm motility is necessary for the release of spermatozoa from the SSTs. The exact mechanism by which sperm are stored in these tubules and released has not been established and hence, this is the focus of this review.

The population of the Middle East and North Africa (MENA) region was 432 million in 2007 and it is estimated that in 2050 this figure will rise to 692 million inhabitants. The poultry industry in the MENA region depends heavily on imported soybeans and soybean meals. About 8.5 million metric tons of soybean meal (SBM) are needed for the production of poultry meat and eggs every year, based on the production of about 8.2 million tons of poultry meat and 3.7 million tons of eggs. Poultry feed prices are consistently increasing because of dependence on imported soybean meal. Hence, it is essential to find sustainable alternative protein sources. Several countries in the region produce sizeable amounts of oil seed meals that can partially or fully replace soybean meal in poultry rations. Nearly 5 million tons of cottonseed meal (CSM), peanut meal, sesame meal, sunflower meal and rapeseed meal are produced yearly in this region. The neighbouring countries of India, Pakistan and Sudan produce over 36 million tons of these meals. This study focused on these five meals in relation to amounts produced, quality and possible levels of use in various poultry rations. Data will be presented on availability, constraints of these meals as replacements for SBM, economic feasibility, and methods of improvement for possible utilisation at higher levels. Oil seed meal digestibility, quality, naturally occurring toxins, antimetabolites, mycotoxins, nutrient imbalances, and prices play a major role in determining the use of these meals for the production of poultry meat and eggs.

Pekin ducks are easily reared in a wide range of conditions. As waterfowl, the growth, digestive system and visual perception of Pekin ducks are different to chickens. Generally, ducks are raised for meat production. The fat content as well as the myoglobin and haemoglobin content of duck meat are higher than that of chicken meat. In duck rearing, both the fattening performance and the quality of meat are important from the consumer's and the producer's point of view. Different rearing systems are used for ducks which affect the welfare, fattening performance, quality of meat and economics of the products. The aim of this review is to discuss the effects of different rearing systems used for Pekin ducks on fattening performance and quality of meat.

Echinacea purpurea is one of the most widely used medicinal herbs that is of interest to animal scientists due to its valuable immuno-stimulatory and anti-inflammatory properties. It is thought that it activates the immune system through stimulating T-cell production, lymphocytic activity, phagocytosis, cellular respiration and inhibiting the secretion of the hyaluronidase enzyme. Chicoric acid (CA) is a major active constituent of Echinacea purpurea. The CA content in roots ranges between 16.80-24.30 mg/g which has gained a lot of renown due to its promising bio-activities. CA has shown to simulate growth promoters and have antioxidant, anti-diabetic, anti-inflammatory, anti-HIV, anti-bacterial, hypoglycaemic and hepatocyte protective properties. There have been very few studies relevant to CA and its use in poultry diets. Previously published studies have included pharmacological and nutritional investigations in the poultry industry. CA could be used as an alternative to antibiotics, and may improve meat quality and health status in broiler chickens.

Factors involved in light management of poultry include source, intensity, duration, uniformity and wavelength (light colour) of light. Research trials have examined the effects of short (blue and green) and long wavelengths (orange and red) on animal welfare, body weight gain, and egg productions in chickens, quail, turkeys, geese and ducks. Blue or green illuminations have a positive effect on body weight and red or white are beneficial to the production of eggs in chickens and quail. During the pre- and post-maturity periods of turkeys, blue light was preferred in the pre-maturity period, whereas the red or white light was better for the post-maturity period. Any noticeable change has not been observed within the body weight gain among the geese under different coloured light; whereas white-coloured light has played an important role in their egg production and semen quality. Positive results have been seen for body weight gain by exposure to red and white light in ducks. The available literature shows that different wavelengths can have positive or negative effects on welfare, body weight gain and egg production of the poultry.

Heat stress is one of the most important physiological factors challenging poultry production throughout the world especially in tropical and sub-tropical countries. Oxidative stress induced by heat stress not only compromises productivity and performance but also results in morbidity and mortality losses leading to the economic burden for poultry producers. It reduces the shelf life of poultry product in addition to poor meat and egg quality. Recently, a trend towards using phytochemicals derived from natural sources with potential antioxidant activities has increased. Lycopene is a predominant carotenoid pigment which is universally found in fruits and vegetables, with tomatoes and their products being key sources. Several in vivo and in vitro studies have suggested that lycopene is a powerful antioxidant compared to other carotenoids. Supplementation of tomato (Solanum lycopersicum) derived lycopene revealed numerous health promoting activities in poultry birds, such as anti-oxidant, anti-inflammatory, immunomodulation, improved performance and better meat as well as egg quality. Lycopene maintains oxidative balance in birds through various ways including serving as a free radical scavenger, inhibiting signalling pathways and activating host antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT). The aims of this current review are to summarise mechanisms of action through which lycopene quench reactive species and maintain oxidative balance, highlight the potential role of lycopene as a natural antioxidant agent for poultry industry and examine the benefits to poultry producers when using this natural antioxidant on commercial basis in poultry diets to alleviate the adverse effects of heat stress.

Studies have shown that dietary chromium (Cr) supplementation beneficially affects physiological functions such as cell preservation, antioxidant activity and immune response that are of utmost importance to animal homeostasis and thermoregulatory capacity under heat stress conditions. For instance, Cr is essential for the synthesis of the specific low molecular weight Cr-binding-substance (LMWCr) that upon conversion to chromodulin, activates the insulin signalling cascade. This results in greater cell permeability to insulin, with a subsequent positive effect on the metabolism of carbohydrates, lipids and proteins. Furthermore, Cr has antioxidant properties which help to attenuate the negative effects of oxidative stress. With regards to meat quality, Cr decreases lipid peroxidation. It has been suggested that Cr supplementation increases antibody responses and lymphocyte counts in broiler chickens exposed to high environmental temperatures. In addition, trivalent Cr supplementation increases growth performance and decreases the circulating levels of undesirable metabolites and hormones such as cholesterol and corticosterone in broiler chickens exposed to heat stress. The aim of this review was to report the effects of Cr supplementation as a nutritional strategy to increase growth performance, immune response, carcass characteristics and meat quality of broilers produced under hot conditions. This knowledge may contribute to improve the productivity and sustainability of broiler production in a context of global warming and development of livestock production in hot climate areas.

Heat stress is one of the main challenges in poultry production as it reduces performance in broilers and layers. This review focuses on the impact of heat stress in poultry production with emphasis on broilers and layers, methodologies to measure the severity of stress and dealing the preventive measures to alleviate stress due to heat. Potential use of naked neck and frizzle genes is highlighted. Nutritional interventions including offering a balanced diet, increasing energy, required amino acids, vitamins like vitamins A, E, Se and minerals like Ca, Na, Cl and K additional supplementation of vitamin C, provision of cool water at levels of up to five times of feed intake to satisfy the special needs during heat stress all have proven advantages. Designing housing with gable type roofing and open sided, wet curtains/exhaust fans, tunnel ventilation in environment control houses, provision of more floor space and free movement, to exhibit natural movement and decreasing flock density is useful to minimise stress as well as to regulate the temperature in micro environment. Thermos tolerance in birds can be enhanced by early feed restriction, good management with better ventilation and developing of heat tolerant breeds by selecting for less feathers. Selection of breeds suitable to climate, nutritional manipulation and small management changes can minimise heat stress in birds.

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