The paper addresses all feasible applications of long ahemeral light cycles in breeding flocks and reviews the limited published studies. Long cycles are likely to be most beneficial towards the end of the production cycle – when eggshell quality is often poor – and at the beginning of lay to increase the proportion of eggs exceeding the minimum weight for incubation. Published reports show an improvement in both fertility and hatchability of breeding flocks under long cycles.

Animal protein supplements are superior to plant protein supplements as sources of essential amino acids and are desirable components in poultry feed formulations. Fish meal and meat meal are widely used animal protein supplements in the Asian and Pacific regions. The nutritive value of these two ingredients and other potentially useful sources of animal protein are examined, with particular emphasis on protein quality. The value of some ‘novel’ animal protein sources is also discussed.

The food intake and growth rate of broilers kept at high temperatures can be improved by supplementing the diet or the drinking water with sodium bicarbonate. The response appears to be due to the bicarbonate ion and is associated with an increase in water consumption. Measurements of dietary or retained values for cation–anion balance or dietary electrolyte balance were unsatisfactory for predicting the growth and/or feed conversion responses of broilers at high temperatures. Improvements in body weight do not appear to be associated with increased body water retention.

The avian kidney has shown a remarkable ability to maintain adequate and even normal function in the face of a mycotoxin challenge. Full evaluation of the nephrotoxicity of a substance must therefore go beyond pathological and ultrastructural documentation and include a complete functional evaluation. To date, only three nephrogenic mycotoxins, citrinin, ochratoxin A, and aflatoxin B1 have been assessed for their ability to alter avian renal function. At non-lethal doses, citrinin appears to have acute reversible effects on the distal portion of the nephron, possibly acting to inhibit water absorption. Ochratoxin A is more potent and less acute than citrinin but less site-specific in that both proximal and distal tubules are damaged, resulting in severe loss of both fluids and electrolytes. Aflatoxin B1 at a dosage and duration which induced hepatotoxicity, concurrently exerted nephrogenic effects such as increased urinary calcium excretion and decreased inorganic phosphate excretion. In commercial broilers aflatoxin B1 has been shown to decrease plasma levels of 25-hydroxy vitamin D, 1,25-dihydroxy vitamin D and may also decrease endogenous parathyroid hormone synthesis and the renal sensitivity to parathyroid hormone. Furthermore, exposure to aflatoxin B1 may cause prolonged alteration in renal function such as reduced glomerular filtration rate. This review summarizes the studies which have been conducted to evaluate avian renal function during both acute and chronic exposure to these three mycotoxins.

Consumer demand for food products of superior health quality has renewed interest in modifying the lipid composition of poultry meat and eggs. While work involving the reduction of the cholesterol content of poultry products has met with little success, dietary fatty acid modification has proved to be a viable method of adding value to poultry products for the health conscious consumer. Because of the association with a decreased risk of coronary heart disease, recent dietary fat studies have centred on the manipulation of specific fatty acids, i.e. 20-carbon omega-3 fatty acids (eicosapentaenoic acid 20:5n3, decosahexaenoic acid 22:6n3) found in marine sources. Seasonal availability, affordability and consumer preference often limit fish consumption, thereby excluding the primary source of 20-carbon omega-3 fatty acids. Enrichment of poultry meat and eggs with these fatty acids might provide an excellent alternative source. The omega-3 fatty acid content of both poultry meat and eggs can be readily increased by the inclusion of marine oils/meals in the diet. However, off-flavours associated with carcass and egg samples enriched in this way have prompted investigations into the use of terrestrial sources of omega-3 fatty acids. While effective in enriching meat and egg products with linoleic acid (18:3n3), plant sources result in only minor changes in the content of 20-carbon omega-3 fatty acids. Various methods of oil refinement and extraction, as well as alterations in production practices and the use of dietary antioxidants have been examined as ways to improve flavour quality and storage stability of omega-3 fatty acid enriched products. Continued investigation in the areas of sensory evaluation and product stability are needed if significant improvements in the health quality of foods available to the consumer are to be made.

Poultry production in India has made rapid progress in the last three decades. The estimated 27 billion eggs produced in 1991 represented a 12-fold increase compared with 1961. Broiler production, which was only four million in 1971, increased to around 250 million in 1991 – almost a 60-fold increase in 20 years. The retail value of poultry and poultry products was about 35 billion rupees in 1991 compared with around 8 and 0.65 billion rupees in 1980 and 1961, respectively. The increase in poultry production also created employment for about 100 000 farm workers. Efforts are directed at achieving self-reliance and self-sufficiency in all spheres of poultry production by 2000 A.D. The annual output of eggs is likely to increase to 40 billion and broiler production to 400 million during this period. Not only will this increase the per capita availability of eggs and poultry meat and so help in the fight against malnutrition, it will also provide many additional job opportunities. To achieve these objectives more emphasis is being placed on applied research, the creation of infrastructure, and on facilities for producing adequate numbers of trained people. There is also greater effort aimed at stimulating transfer of technology and making more investment capital available from financial institutions. This in turn will contribute to improved rural production, greater diversification within the poultry sector, and the introduction of basic quality control at all stages of production and marketing. The scope for market intervention to help provide producers with reasonable prices is being assessed. The opening of Indian markets to non-resident Indians and others interested in poultry development and accelerating the pace of development by the creation of appropriate organizations such as the National Poultry Development Board and the National Bureau of Poultry Genetic Resources, are also envisaged.