Poultry researchers and nutritionists are looking for viable alternative feed additives since conventional supplements have been criticised for their potential negative impact on the food chain. Among the currently available poultry feed additives, natural herbs and plants have been widely advocated due to their reported widespread beneficial effects. Garlic (Allium sativum) is one such potential feed supplement which has recently been reported as having a wide range of beneficial effects on the production performance and physiological biochemistry of broilers and laying hens. Notable beneficial effects have been seen on growth, feed efficiency, egg production and quality, as well as stimulation of immune system and lowering blood cholesterol levels in poultry birds. The results reported vary from author to author probably due to variations in the dose of the product fed, the duration of feeding and processing techniques employed.

Deoxynivalenol (DON) is prevalent worldwide in crops used for food and feed production. The presence of mycotoxins in poultry feeds is a significant factor contributing to financial losses in animal industries. DON causes losses in livestock production and poses a health problem to livestock and humans consuming contaminated cereal products. Although DON is one of the least acutely toxic trichothecenes, it should be treated as an important food safety issue because it is a very common contaminant of grains. Poultry respond to increasing dietary DON concentrations with a reduction in productivity only at high levels (above 5 mg/kg) but there is no evidence of a clear dose-response relationship. Poultry fed low to moderate doses are able to recover from initial weight losses, while higher doses induce more long-term changes in feeding behaviour. At low dosages of DON, haematological, clinical and immunological changes are transitory and decrease as compensatory/adaptation mechanisms are established. The exposure to higher dose levels of DON are mainly expressed as severe reductions in body weight and impaired resistance to infection, particularly bacterial infection. Common symptoms of acute toxicity of DON are nausea, vomiting, dermal irritation and lesions, haemorrhagic lesions and pathological changes in the haemopoietic organs.

The capacity of DON to alter normal gut and immune function has been of particular interest. One important aspect of DON toxicity is an injury of the gastrointestinal tract. It was found that DON had an influence on intestinal nutrient absorption and the intestinal morphology of chickens, especially in the duodenum and jejunum, as evidenced by shorter and thinner villi. DON decreases glucose and amino acid absorption in the chicken's small intestine in vivo and in vitro and this effect is apparently mediated by the inhibition of the sodium D-glucose co-transporter. It was found that immune function decreased in broiler Leghorn chicks that were fed DON-contaminated diets. It induces changes in the hematopoietic system of chicks and alters immune response, whereas, DON impairs mitogen-induced proliferation of lymphocytes. The feeding of DON-contaminated grains decreased serum antibody titers against Newcastle disease virus (NDV) and infectious bronchitis (IB) in laying hens and broilers. The impact of DON on the immune system and gastrointestinal tract are important to define the maximum tolerable levels of DON in animal feedstuffs. The purpose of this review is to summarise the information to date regarding the toxicological and immunological effects of DON on poultry.

The aim of this work was to perform a review of the bibliographic data regarding the spreading of rickets, as well as of its associations with certain pathological conditions in broiler chickens that had been exposed to rickets. The literature suggests that the occurrence of subclinical and clinical rickets within broiler flocks are a possible prerequisite for a number of pathological conditions such as femoral head necrosis (FHN), osteomyelitis, fractures, tibial dyschondroplasia (TD), vertebral column deformations with clinical expressions indistinguishable from spondylolisthesis, chronic respiratory disease (CCRD), ascites syndrome and other conditions related to morbidity within flocks. The gross lesions in the proximal tibiotarsus can be used for differentiation of clinical hypocalcaemic and hypophosphataemic rickets in broiler chickens. Macroscopically, hypocalcaemic rickets are hardly distinguished from tibial dyschondroplasia because the latter condition may be a consequence of the former in its etiological aspect.

Modern commercial broilers appear to have compromised immunocompetence, higher mortality and lower resistance to stressors. To overcome these, dietary manipulation seems to be the easiest approach, and this has been supported by research investigations conducted over the last few decades. The goal of enhancing the immune system of broilers is laudable for both economic and welfare reasons. Vitamin E (VE) is now well accepted as nature's most effective lipid-soluble, chain-breaking antioxidant. This antioxidant vitamin has been shown to improve both cell-mediated and humoral immunity in broiler chicks. However, the effect of this vitamin depends upon dose, age and genetics of the broiler chicks. Several mechanisms have been postulated for the beneficial effects of this vitamin. In this review, several aspects of the immunomodulatory effects of VE are reviewed.

Many cues for selection exist in poultry breeding, giving important insights into the future selection of elite progeny. Among these cues, the comb is an important reliable parameter for selection within variety or breed. The development of the comb is associated with hormone levels in the body which affect both productive and reproductive parameters. Comb affects the mating behaviour of birds and may be used as an indicator for selection by examining its impact on performance. Strong selection for increased comb size has been shown not to affect male mortality but is linked to increased female mortality. The production traits of layers have a positive correlation with comb size. The following paper provides a review of the comb as an important ornamental trait, including its morphology, development, use as a selection tool and the effect of comb size on productive and reproductive traits.

In the last decade, there has been growing interest in the use of natural herbs and medicinal plants as feed additives in poultry diets to maximise their potential output. Ginger is one such potential rhizome with a wide range of medicinal effects. In broilers and layers, this plant has been used in different forms, doses and durations. In this review, documented effects of ginger in poultry feed on feed intake and feed conversion ratio, growth and weight gain, carcass yield, egg production and quality, antioxidants and blood biochemistry, with their possible mechanisms of action, are discussed.

Broiler ascites, first seen in the form of a high altitude disease, has increased in importance world-wide in direct proportion to the improvement in growth performance of modern broilers. At the same time, the incidence has spread gradually from high altitude (above 2000 m) down to sea level, which gave rise to proposals of alternative causes including infections, toxins and metabolic disorders. Our work centred on anatomical and physiological aspects and included hypoxia models, chemotherapy and selection for genetic resistance. The latter led to the development of ascites-resistant lines, which allowed resistant stock to become commercially available in South Africa.

The closure of the Poultry Section of the Onderstepoort Veterinary Institute brought ongoing ascites research to an abrupt end and some of the completed work was never published. This review of completed, ongoing and planned ascites work was at the time compiled as final report to the Director of the Institute in 1990. It came to light again recently and has been edited for publication. It also includes a new hypothesis on the reasons for the susceptibility of the domestic fowl and particularly broilers to hypoxic ascites.

The maximum efficiency requirements in poultry include management, health, nutrition and environment. However, the interaction of these factors is not always met, generating malfunctions in the metabolism, physiology and anatomy. The incidence of leg weakness in rapidly growing birds has become a major concern in the poultry sector, not only due to poor performance and condemnation in processing plants, but also to compromised animal welfare. This article aims at reviewing the main nutrition-based diseases affecting the locomotor system of broiler chickens.

The feasibility of feeding insects on different types of waste materials and subsequently feeding insects to poultry is reviewed. Research in this area has demonstrated that a number of insect taxa including silkworms, locusts, fly larvae, crickets and grasshoppers can be safely fed to chickens without compromising the quality and palatability of the meat. Most studies on the topic have dealt with which species of insects can be fed to chickens; they did not investigate rearing insects commercially which requires knowledge of insect rearing, feeding and production methods. This review examines this issue in greater depth by reviewing current literature and through discussions with the poultry farmers in the states of New South Wales and Queensland, Australia. A survey of poultry farmers found an acceptance of feeding insect to poultry provided it could be done economically and indicated that insects could be reared and fed on a variety of organic waste materials which are available in adequate amounts in different regions. The technique of feeding insects to poultry will be beneficial in developing agriculture based recycling systems, reducing waste and potentially aid in reducing environmental pollution. Depending on the insect species and whether the diet of insects is fed to meat producing or egg laying birds it will likely need to be supplemented with either or both calcium and limiting amino acids to meet the chicken's dietary requirement. The safety and economic viability of breeding and rearing insects on organic wastes and feeding to poultry needs to be assessed. In order to be economically feasible, the overall cost of rearing and feeding insects to poultry needs to be lower than the cost of feeding conventional protein sources like grains and soybean meal. The technique of feeding insects to poultry needs to be able to be easily adopted and readily adaptable by the industry to a range of farming systems. Further research needs to investigate these issues in more detail both by establishing small experiments and developing production models which include insects reared ‘onsite’ in the poultry diet.

Lithuania committed itself to conservation of its genetic resources by signing the Conservation Convention on Biological Diversity in Rio de Janeiro on June 11, 1992. In 1995 FAO recognised the Vishtines goose breed as being monitored internationally and included into the FAO Global Databank for Animal Genetic Resources and the World Watch List for Domestic Animal Diversity. Vishtines geese are rather large in size with a medium-sized head, blue eyes and straight short orange beak. The arched neck is of medium length. The breast is broad and deep. The back is straight, horizontal and the shanks are long and orange. There are one or two skin folds on the abdomen. The plumage is white. The final body weight of the goose and the gander of this breed reaches 5-6 kg and 6-7 kg respectively. Numerous scientific studies have been made with these geese in Lithuania. Biochemical protein polymorphism and microsatellite analysis tests with the goose breeds grown in Lithuania indicated that Vishtines goose breed is unique and can be distinguished by biochemical genetic individuality.

The following review discusses the findings of existing research surrounding the nutritional impact of leaf meals as incorporated in chicken diets, the importance of forages in sustainable poultry production and the capacity of hens to digest high fibre diets. The potential of conventional and/ or outdoor based systems for developing countries, the effects of outdoor production systems on the welfare of laying hens, and methods used in measuring forage intake and the feed items obtained by hens from the outdoor area are also discussed. This review highlights those factors affecting range utilisation, behaviours of free range hens and the recommendations for better range utilisation by laying hens, particularly in the tropics.

With a growing population, feeding competition between human and animals is increasing. Because major ingredients used in animal feeds, especially in poultry diets are now being used in human nutrition, there is a decreased availability of quality feed resources and poultry feeds are becoming costly. Guar meal is an easily available and economical feed ingredient and may be helpful in alleviating this problem. A large quantity of guar is processed in the world for gum extraction and residue left over from processing is converted into guar meal. It has a good amino acid profile with crude protein contents of about 33-45%. However, anti-nutritional components like guar gum (β-mannan), saponins and trypsin inhibitors limit the use of guar meal in broiler diets. These anti-nutritional factors have been reported to depress growth in birds but at lower levels some of these (β-mannan and saponins) have positive effects on bird health and performance. β-mannan is considered a major anti-nutritional factor when higher levels of guar meal are used in poultry. To improve the utilisation of such feeds, β-mannanases are used. This paper reviews some benefits and drawbacks regarding the use of guar meal in poultry diets and how to improve its feeding value.

Recent studies have suggested that avian semen contains a high proportion of polyunsaturated fatty acids (PUFAs) which are characterised by an increased susceptibility to lipid peroxidation. Free radicals are produced as a consequence of lipid peroxidation and these can impact on the fertility of male birds. The seminal plasma has been equipped with a defence mechanism called antioxidant capacity which protects semen integrity against the negative impact of ROS (reactive oxygen species). From the available literature, it can be surmised that lipid peroxidation is one of the major causes of low fertility in male birds which can be remedied with supplementation of exogenous vitamin E. Vitamin E provides biological stability to spermatozoal plasma membranes by inhibiting the generation of reactive oxygen species (ROS). Recent studies have suggested a role of vitamin E in improving semen quality and subsequent better fertility. In this review the current knowledge of physiology of ROS and antioxidative role of vitamin E to treat avian male fertility is discussed.

Newcastle disease (ND) continues to be a problem in many developing countries. Successful disease control and diagnosis is often difficult because of a lack of biosecurity at farm level, cost-effective field-based diagnostics and seromonitoring tests. The use of fixed chicken red blood cells has been reported to be useful for haemagglutination (HA) and haemagglutination inhibition (HI) tests to avoid the cumbersome process of regular blood collection and processing of cells. However, virus isolation and biological characterisation or molecular tests such as polymerase chain reaction followed by sequence analysis are still essential for rapidly pathotyping the epizootic virus isolates. The demonstration of Newcastle virus (NDV) along with case history and clinical signs is of diagnostic importance in unvaccinated flocks. Monoclonal antibodies are not always very effective. The need for the collection of suitable specimens has been reviewed in this study. The disease is mainly controlled by using live vaccines when vaccinating the flock. The live virus vaccines persisting in the poultry house environment seem to be gaining virulence. Efficacy of the vaccine to be assessed reflects the immune status of the vaccinated birds. Filter paper sampling method of sample collection and HI test are reported to be successful for large scale seromonitoring programmes. This review concentrates on different diagnostic tests and their usefulness under field conditions for rapid identification of the disease so that control measures can be implemented at an early stage.

Mineral availability is one of the most important concerns in poultry nutrition. In modern, high-producing, meat and laying poultry, mineral metabolism disorders often lead to decreased eggshell quality and osteoporosis in laying hens and bone weakness in broiler chickens. This has negative effects not only on the economic profitability of production but also on the welfare of the birds. The article discusses the results of studies on the effect of chosen feed additives, namely organic acids and prebiotic fructans, on mineral utilisation in poultry. The results of some of the experiments presented in the article indicate that the use of these additives may have a positive impact on mineral metabolism in poultry.

Published literature on the effect of carbohydrase enzymes (CE) on energy availability, nutrient digestibilities and growth performance of broilers fed corn-soybean meal-based diets is reviewed. Data from experiments involving CE preparations displaying single- to multiple-activities has shown improved metabolisable energy by 3% and digestibility of protein by 5%. Despite the observed variation in absolute values for individual amino acids, the improvement in amino acid digestibility appeared to be 27% of the undigested fraction. The positive effect on nutritive value are consistent with the improvements in body weight gain (0.8 to 10.4%; mean = 4.3%) and feed efficiency (1.3 to 9.3%; mean = 3.7%). Possible mechanisms contributing to these effects and the factors thought to explain the variability in responses has been discussed.

Laying hens have a unique bone turnover due to the daily egg laying cycle. Laying hens have three distinctive kinds of bones related to egg formation: cortical, cancellous, and medullary bones. Cortical bone is a compact structural bone, whereas cancellous bone is the three-dimensional lattice-like honeycomb architecture at the end of long bones. Medullary bone is a highly labile woven bone lying in the marrow cavities. Medullary bone acts as Ca storage for egg shell formation. Thus, bone quality is closely related with egg production and eggshell quality. During the daily egg laying cycle, medullary bone osteoclasts alternately cease and accelerate bone resorption. Although osteoclast numbers are not changed during the daily egg laying cycle, considerable morphological changes in osteoclasts occur along with changes in calcium requirements for egg shell formation. Furthermore, the selection of proper methods is critical to obtain precise bone evaluation data, and include bone ashing, densitometric techniques, mechanical testing, or histomorphometry to evaluate bone status in laying hens. Since bone metabolism in laying hens is related to economic and animal welfare issues, better understanding of bone metabolism in laying hens would be important to enhance productivity and improve animal welfare.

During outbreaks of highly pathogenic avian influenza in Cambodia, local non-governmental organizations managed to strategically influence decision making processes in inter-governmental organizations by highlighting human death tolls, public health, and rural livelihoods. This was accomplished through active participation in conferences, consultations, meetings, and workshops as well as disseminating messages via articles, papers, reports, studies, and websites.

Among more than 750 known carotenoids, canthaxanthin (CX) has a special place as a carotenoid with proven antioxidant and other biologically-relevant functions. A substantial body of evidence indicates that CX possesses high antioxidant activity which has been shown in various in vitro model systems as well as in animal experiments in vivo. It seems likely that the highest protective effects of CX are seen under various stress conditions. This compound may be considered as an important element of the integrated antioxidant system of various tissues in the body, including chicken embryo development. A possibility of the recycling of vitamin E by carotenoids, including CX, is of interest for further investigation. Taken together, the data analysed in the paper clearly indicated that CX could provide benefits for animals, including in eggs and embryos as well as for chickens during early postnatal development. In particular, CX is well absorbed from the diet and effectively transferred to the egg yolk and developing embryo. It possesses high antioxidant activity and participates in building an effective antioxidant system of the body.

The uses of a prebiotic to replace antibiotic growth promoters, mycotoxin and cholesterol binders in broiler diets have been commonly practiced over the last three decades. Many products have appeared commercially to replace antibiotic growth promoters and to tackle the problems of mycotoxins contamination. Mannose-based carbohydrates, particularly mannan-oligosaccharides from yeast, appear to have properties of coping with the mycotoxin related problems. Over the last three years, studies on the use of copra-mannan (CM) in this respect have produced promising results. CM has been found to effectively improve bird performance. When the birds were challenged against Escherichia coli, the supplementation of the feed with CMs was able to maintain growth performance of birds to the same level as the growth of birds fed commercial mannan-oligosaccharides or antibiotics. Contamination of feed with 0.3 ppm aflatoxin B1 reduced feed digestibility, but not when the feed was mixed with CM. The supplementation of the diet with CMs protects the birds from wet droppings when the birds were challenged by either Escherichia coli or aflatoxin contamination. Since there is a conflicting information about using mannans in the diet, particularly between using legume mannans as an antinutrient and yeast mannans as a pronutrient, this paper reviews the potential use of CMs for the purposes of promoting growth and improving health status of broiler chickens.