This paper reviews the literature on the response of young domestic fowl to various food restriction patterns. Emphasis has been given to anatomical, endocrine and immunological factors and their interactions with the genetic background. Under restricted feeding (limitation of the amount or time of access to food) chickens learn quickly to ingest the allocated quantity of food within a short period of time. When exposed to a single sequence of food removal and restoration, body weight losses are reduced for non-adapted compared with adapted individuals, for light breeds compared with heavy breeds, and for older compared with younger chickens. Adaptation to food restriction includes increased capacity and slower evacuation of the gastrointestinal tract (mainly the storage organs) to increase the supply of nutrients during the periods of food deprivation; increased hepatic lipogenesis and glycogen synthesis during the feeding cycle; and decreased heat loss on days of food deprivation. Synthesis and secretion of digestive enzymes in response to intermittent feeding has been found to be population dependent and consistent with the hypothesis that the amount of intestinal chyme mediates the synthesis and excretion of digestive enzymes from the pancreas. Numerous hormones are directly or indirectly involved in the metabolic responses to food restriction. Hyperinsulinaemia, increased plasma levels of growth hormone, triiodothyronine, thyroxine and plasma prolactin have been observed after the reintroduction of full feeding. It is suggested that the altered hormonal environment induced by food restriction contributes to a metabolic situation that may enhance immunocompetence.

The incidence and numbers of numerous pathogenic organisms on raw processed poultry have been well documented in the scientific literature. This paper is an attempt to summarize the data in a logical manner, and is timely and useful because of growing concern regarding the microbial safety of poultry products. The literature relating to pathogens commonly associated with processed poultry is extensive, so future surveys should concentrate on those which are emerging.

Broilers are currently reared under nearly continuous lighting (CL) schedules. However, the suitability of such lighting regimens may be questioned in terms of performance and welfare. This paper reviews the literature concerning the effects of intermittent lighting (IL) schedules on these issues. Final body weights at market age of broilers reared under IL schedules are equal to, or even higher than, those of broilers reared under CL schedules. However, endogenous (genotype and sex) and exogenous (dietary composition, feeder space, etc.) factors may interact with the lighting schedule. In contrast, feed conversion is consistently improved with IL, partly as a consequence of a more concave growth curve (initial growth depression followed by compensatory growth). Inconsistencies in the literature concerning the effect of IL on (abdominal) fat content and dressing yield are caused by interactions with other factors. However, it is clearly demonstrated that IL reduces leg abnormalities, in particular the incidence of twisted legs. Additional welfare benefits of IL are found in reduced physiological stress and improved eye condition. An increase in the amount of catching damage has been observed with IL, but this may be avoided by modifying light management before commencement of the catching operation. The importance of light is not restricted to the lighting schedule; aspects of the light quality are also important. Although the data related to light intensity are conflicting, it is generally recommended that an intensity of 51ux should be provided. Whilst fluorescent light does not affect broiler performance adversely, its lower use of electricity compared with incandescent lighting does reduce input costs. More research is needed to evaluate the impact of these qualitative aspects of lighting on poultry welfare.

A considerable volume of research on fertility in poultry, especially that associated with artificial insemination and related technologies, has been undertaken and published by scientists working in the institutes of the former USSR, now the CIS States. Researchers outside this geographical area have largely ignored this work, presumably because of the language barrier and limited accessibility of published material. That is particularly unfortunate, because in areas such as sperm cryopreservation the work of these institutes is clearly more advanced than in other countries. This paper sets out to redress the balance by reviewing artificial insemination research performed on various species of poultry, including semen extension, liquid storage and sperm cryopreservation, in the research institutes of the former USSR/CIS States.

Chicken anaemia virus (CAV) is a small, naked, icosahedral virus with an SS-DNA genome of 2.3 kb. The virus infects very young chicks (vertically by transovarial transmission) and causes anaemia, immunosuppression and skin lesions (CAV syndrome). The virus also infects older birds (by horizontal transmission) with no apparent signs of infection, although growth may be affected. In Australia the CAV syndrome is currently controlled by exposure of breeding stock to wild-type virus (no attenuated virus is available). The authors are currently investigating CAV-specified proteins and an attenuated virus vaccine and developing an ELISA for antibody detection with the Division of Animal Health, CSIRO.

Fear is now widely regarded as an undesirable state of suffering by many members of the public, the scientific community, welfare and policy groups, as well as by a growing number of farmers. At first glance this view appears to be inconsistent with one based on biological significance, in which fear is regarded as an adaptive state with fear behaviour functioning to protect the animal from injury. Fear is often adaptive in ideal circumstances but neither we nor the animals in our care live in an ideal world. In reality, many farming systems prevent the animals from responding in an adaptive fashion to potentially threatening stimuli. In these circumstances, fear can be a powerful and potentially damaging stressor, particularly if it is intense or persistent. Both acute and chronic fear can seriously harm the welfare and performance of poultry. Certain fear responses, such as violent escape or panic, are inap-propriate in intensive systems and can cause injury, pain or even the death of birds. High levels of underlying fearfulness have also been negatively associated with plumage condition, egg production, egg shell quality, growth, and food conversion efficiency. Furthermore, because fear inhibits all other motivational systems, its elicitation is likely to impair the ability of birds to adapt to environmental change, to interact successfully with each other or with the stock person, and to utilize new resources. Therefore, high fear is clearly undesirable from the bird's and the farmer's viewpoint and its reduction is of major importance. This objective had been hampered because of the complex-ity of the concept of fear and the controversy over its measurement. However, operational definitions of fear and its components are given in this review and a number of tests which have been used to measure fear in poultry are described. Strong intra-individual correlations found between the fear scores afforded in many of these tests suggested that they are measuring the same intervening variable, presumably underlying fearfulness, rather than purely stimulus-specific responses. Two of the commonest and potentially most frightening events encountered by poultry are sudden changes in their physical or social environment and exposure to humans. Other more specific types of alarming stimuli are also listed. Hitherto, the most promising ways of reducing underlying fearfulness and increasing adaptability, at least in the laboratory, involve one or more of the following approaches: environmental enrichment, regular handling or related treatments, vitamin C supplementation of the diet or drinking water, and genetic selection. The potential benefits and short-comings of these remedial measures are discussed, with attention to their practical relevance as well as to their more fundamental implications. Other measures to mask and/or minimize the incidence of frightening events are also briefly mentioned. Our objective should be not only to achieve a balance between maintaining an emotional state that facilitates the avoidance of danger while reducing the likelihood of overreaction and the expression of inap-propriate responses, but also to provide a stimulating, safe but economically viable environment. Continued investigation should enable recommendations to be made concerning the most effective programme, in terms of environmental modification, human-animal interaction, nutritive manipulation, and selective breeding, in order to achieve the optimal levels of fear in poultry, whatever the future trends in the industry.

The physical characteristics and chemical composition of ostrich eggs are reviewed in the process of investigating their suitability for table consumption. Some comparisons are made between ostrich eggs and those of other avian species, and it is concluded that their physical appearance may make them attractive to consumers. The extremely strong shells of ostrich eggs make them very resistant to breakage during handling and transportation, while also serving as a basis for the making of curios. The limited data available indicate that the contents of ostrich eggs is similar to that of other avian species in terms of the proportion of main components and chemical composition. Although the production of fresh ostrich eggs for consumption is currently not seen as having great potential, there appears to be no reason why those not used as hatching eggs should not be utilized for table consumption.

Chlamydiosis of domestic poultry (chickens, pheasants, guinea fowl, quail, ducks, geese, and turkeys) is reviewed with emphasis on psittacosis as an occupational disease. The article covers literature from 1940 to 1994. The potential risks of transmission of C. psittaci from poultry to man are discussed, and clinical diseases caused by C. psittaci infection in man are briefly reviewed. Ducks, sometimes without clinical signs, and turkey flocks usually conspicuous for ornithosis during transport or processing, are the most likely sources for poultry transmitted psittacosis. Isolation of the chlamydia, both from man and birds, is the best method for confirmation of the diagnosis. In humans an easier, but less reliable, way is the demonstration of a significant titre rise in properly spaced paired serum samples combined with clinical symptoms. False positive results can occur with the complement fixation test (CFT) commonly used. It has to be remembered that there is a high prevalence of antibodies to different Chlamydia spp. in the population, and that the genus-specific antigen used in the CFT recognizes antibodies to all these pathogens and antibodies resulting from prior infections. More specific serological tests should be favoured, and highly sensitive and specific DNA detection methods, currently mostly used in research, will probably replace tests like the CFT. Case reports of outbreaks of the disease especially among poultry plant workers are compared. With awareness of the problem, employees knowing the clinical signs of psittacosis both in poultry and man, modern abattoir machinery, good sanitary conditions, and early treatment with effective drugs when necessary, the disease risks can be minimized.

Several successful methods of inducing moulting have been used to recycle laying hens, the majority of which require an optimum weight loss of 25–30% to achieve maximum egg production during the post-moulting period. The conventional feed restriction procedure is most often used in the egg industry because it is a simple, practical and economical technique that can be used in combination with light and/or water restriction. Mineral-induced moulting procedures, such as the use of high levels of either aluminium in the form of a soluble salt or dietary zinc, have also been used successfully. In addition, low levels of dietary zinc combined with a low calcium diet have also induced moulting in laying hens. The use of low sodium diets has been equally as successful as the conventional feed restriction technique as a means of inducing a moult. Although mineral-induced moulting procedures produce similar results to the conventional feed restriction techniques in post-moulting egg production, but with lower mortality rates, some of these procedures may not yet be practical for use in the egg industry. Hormone-induced moulting is another method and involves the use of the gonadotropin-releasing hormone (Gn-RH) agonist. It has an advantage over the conventional feed restriction procedure in that it does not require severe initial body weight loss to attain maximum egg production in the post-moulting period.

A major goal of many poultry producers is to attain good flock liveability. Historically, most poultry producers have manipulated environmental conditions and management to maximize bird health. In the past two decades there has been much research into nutritional regimes that improve bird health through immunomodulation. Commercial poultry environments contain ubiquitous micro-organisms that continuously challenge the immune system. Nutritional supplements that enhance immune system function may improve flock performance and be economically advantageous. This paper reviews the literature on zinc-methionine and the avian cellular immune system. Current knowledge of the effects of zinc on many animal models is reviewed and a hypothetical mechanism for the action of zinc-methionine on this system is discussed.

The phenomenon of compensatory growth in broiler chickens subjected to early life undernutrition is reviewed. Increased interest in this concept is attributed to problems associated with early life fast growth rate, especially in broilers fed ad libitum. These problems include high body fat deposition, and a high incidence of skeletal and metabolic disorders. Factors that influence compensatory growth in the broiler chicken include the nature, severity and duration of undernutrition, as well as the age at the commencement of undernutrition and the degree and pattern of realimentation. Many studies have reported improvement in feed efficiency during compensatory growth in restricted-refed broilers. Broiler chickens undergoing compensatory growth also exhibit greater than normal feed intake relative to body weight and some associated digestive adaptation. The use of this concept to address problems associated with early life fast growth rate requires more studies of the nutrition of the broiler chicken during the period of growth compensation.

Feed additives are renamed as microfeedingstuffs. They are subdivided into nutrients, pronutrients, conditioners and prophylactics in order to specify their nature and scientific functions in nutrition, to improve their public image and to facilitate the standardization of their terminology and use in international regulations.

The physicochemical properties of non-starch polysaccharides (NSPs) are responsible for their antinutritive activities in the broiler chicken. In particular, soluble viscous NSPs depress the digestibilities of protein, starch and fat. On the other hand, insoluble and non-viscous NSPs may have a beneficial effect. Fat digestion is used here to illustrate how the physicochemical properties of NSP may interfere with digestion and absorption. It is suggested that the gut microflora can mediate the antinutritive effects of soluble and viscous NSP. It is concluded that the determinations of crude fibre and/or acid detergent fibre and neutral detergent fibre in feedstuffs are not appropriate for predicting and understanding the physiological action of NSPs in broilers. The determination of the in vitro solubility of NSP and the viscosity of the feed ingredient could become of major importance for ‘antinutritional’ evaluation. More research needs to be conducted to study the interactions of NSPs with the microbial activity in the intestinal tract of the broiler chicken.

This paper deals with two aspects of feeding whole grain wheat to poultry. The nutrient availability of wheat, either ground or as whole grain, is compared, and various practical methods of providing whole grain wheat to broilers and laying fowl are discussed.

Despite their widespread use in poultry diets, the ways in which enzymes function are still not fully understood. Whilst it is agreed that a reduction of intestinal viscosity is the most likely mechanism when the appropriate enzymes are used in barley- and rye-based diets, some animal nutritionists claim that this is not so important in enzyme supplemented wheat-based diets. This paper, which attempts to place the relevant pieces of information into context, indicates that, even in the case of wheat-based diets, intestinal viscosity is a major factor limiting bird performance. Thus, in wheat fed birds the use of enzymes to reduce intestinal viscosity is likely to be the most effective method for improving performance. Data are also presented which, contrary to popular belief, indicate that most of the beneficial effects resulting from the feeding of xylanase-based enzymes to broilers are observed in the latter stages of the production cycle.