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SEERAD Programme of Agricultural, Biological and Related Research 2002-2003

THEME 3: ANIMAL PHYSIOLOGY AND PRODUCT QUALITY

SUMMARY OF COSTS:

THEME 3: ANIMAL PHYSIOLOGY AND PRODUCT QUALITY

Livestock products, particularly meat and milk, remain an important output from Scottish agriculture. Consumer demand for high quality products that do not compromise the welfare of animals is increasing. Research described within this Theme covers both the fundamental studies needed to understand the growth, development and functioning of productive tissues, as well as quality attributes of the raw materials and foods derived from them. Since much of the Scotland's agricultural land cannot support commercial crops other than grass, animals are integral to economic production systems. Investigating ways of adding value to animal products is essential to improving the viability of the agricultural sector in Scotland.

Work within this Theme is very relevant to aspects of human biology, in particular the interaction between nutrition, diet and health. Studies on essential micronutrients, especially trace elements, essential fatty acids, vitamins, and phytochemicals and the mechanisms through which they protect against coronary heart disease and cancer are included within the programme. The studies on foetal development are relevant both to humans and to agricultural animals. Work on the mechanisms underlying the development of obesity and major diseases for which this is a risk factor is of particular relevance for Scottish health.

The research in this Theme spans a wide range of approaches from work at the molecular level through studies on cells, tissues and organs to the whole animal. Three major areas are emphasised: nutrition, tissue growth and development and reproduction. Work also includes research on animal product quality, mainly on milk and meat. The scope of these studies ranges from the understanding of the processes taking place within the animal, such as tissue growth or milk secretion, through the effects of different constituents on processing quality, to the design of new products with enhanced quality attributes. Most of this research has grown from programmes originally set up to increase efficient production of animal-derived foods and materials; however the objectives and applications of the high quality, innovative science carried out using animal systems are now much more diverse.

Research within this Theme relates to all end user categories as defined within the ABRG document Strategy for Agricultural, Biological and Related Research 1999-2003. Links with sustainable agriculture, nutrition and human health, and food and bioindustries are particularly important foci for the research on animal systems. The relevance of the work to environment and natural heritage and to rural communities and development centres on the importance of animals and animal products to the economic and social systems which support the rural communities in Scotland.

This Theme forms a significant part of the SEERAD-funded research programme, and as such relates to a number of other areas of the programme. There are obvious links with work on grazing ecology and farming systems in Theme 5, and with the studies of animal disease and gut pathogens in Theme 4.

Much of the large animal science carried out in the UK today is funded within the SEERAD programme; other sponsors traditionally fund work largely in other areas of animal science that are underrepresented in the SEERAD programme (e.g. genetics, which is mainly funded by BBSRC and DEFRA). Where there are subjects within the programme that are also included in the programmes of other funders (e.g. nutrition, diet and health), special care is taken to avoid unnecessary overlap or duplication, and to encourage co-ordination of the research undertaken.

3.1 Nutrition

3.1.1 Cell/Nutrient Interactions

There is increasing interest in the interaction between nutrition, diet and health in the human population. The report Scotland's Health, A Challenge for Us All (1992) highlighted a number of concerns about the Scottish diet and its link to health problems. Understanding all aspects of the links between diet and health can only make improvements to the situation. While there are many aspects to this, the SEERAD-funded research programme has an emphasis on the mechanisms by which dietary derived micronutrients affect susceptibility to heart disease and cancer. Work in this Theme encompasses studies on trace elements, antioxidant vitamins and polyunsaturated fatty acids. All can be shown to have beneficial effects when included in the diet but their mechanisms of action and interactions are not yet well understood. Studies here are aimed at improving that understanding with regard to cellular processes such as gene expression, DNA damage and immune function. Studies on the uptake and metabolism of these micronutrients are also important to understanding mechanisms of action. Once the activity of such nutrients at the cellular level is properly understood provision of dietary advice to humans for maximum health benefit will be possible, both at the population and individual level.

3.1.2 Appetite Control

Studies on the control of food intake within the central nervous system have progressed rapidly since the demonstration of the synthesis of leptin by adipose tissue and its effects on the hypothalamus region of the brain. The studies in this theme involve work on the regulation of appetite, energy balance and body weight. Some of the work uses animal models to investigate the central control of body weight and search for new genes involved in controlling appetite and energy balance. Studies in human volunteers are also being used to investigate the genetic basis for obesity and effective interventions. This work is important in the study of obesity and body weight maintenance. Obesity is an increasing problem in western societies and has considerable health consequences for man. In agricultural species, excessive fatness has not only negative effects on the animal's health and reproductive capacity, but can considerably lower the value of the end product.

3.1.3 Feed Intake - Theory and Modelling Studies

The process by which any animal chooses and consumes food results from the synthesis of a number of sensory and physiological inputs. Understanding how these processes interact is a major challenge to nutritionists. Because of the complexity of the systems involved, a modelling approach can often provide insights into aspects of the process within different animals faced with diverse situations. The projects listed here involves theoretical and modelling studies using grazing ruminant animals. However the fundamental principles investigated are relevant to all animals, including man.

3.2 Tissue Growth and Development

3.2.1 Digestive Tract Biology

The digestive tract is the major site of digestion and absorption of food constituents and also plays an important role in the immune competence of animals. This Theme includes work on the interactions between diet, gut micro-organisms and the host immune system in health and in diseases of the large intestine in man. Ruminants have a particularly interesting digestive tract and work on the micro-organisms found in the rumen, which allows the efficient digestion of grazed herbage, is included here. The objective of these ruminant studies and those on growth of the gut is to improve the efficiency of the ruminant animal in converting grazed and fed material to meat and milk. Like the skin, the gut also forms an effective barrier to invasion of the body by pathogenic micro-organisms. This aspect of digestive tract biology is dealt with in the subsequent Theme, since the focus of that work is primarily on pathogens.

3.2.2 Mammary Gland

The primary function of the mammary gland is to provide nourishment for the young. This is essential to the successful production of viable offspring in mammalian species. Milk from the dairy animal is also an important output of Scottish agriculture, both in its natural form and increasingly as processed products such as ice cream or cheese. Much of the work in this theme is aimed at understanding the physiology and cell biology of mammary tissue. The mammary gland is also a good model system for the study of important aspects of cell biology, including apoptosis and cell morphogenesis, which are also relevant to aspects of human breast cancer.

3.2.3 Structural Tissue

Work within this Theme is aimed at understanding the basic biology of muscle tissue, with particular reference to growth and development phases. The work on muscle is closely aligned with studies on the quality attributes of meat and how these relate to muscle development. This work is described more fully in Theme 3.4.2. Work listed here also involves investigation of the abnormal metabolism of structural proteins characteristic of a number of debilitating conditions, including heart disease, and other diseases of ageing associated with fibrosis. This research aims to understand the processes that lead to the altered metabolism, and to identify targets for therapeutic intervention to alleviate the debilitating conditions.

3.2.4 Regulation of Growth and Development

The integration of physiological processes in animals occurs by a variety of mechanisms operating primarily through endocrine systems. Effects may be elicited at organ, tissue and cellular levels, and involve a high level of co-ordination between the systems to ensure stability. Studies in this Theme include work on fundamental regulatory mechanisms operating at the physiological level relating to growth and development in animals. This work is relevant both to farmed animal species and to human growth and development in healthy and diseased states.

3.3 Reproduction

3.3.1 Fertility

Ovulation, the release of the ovum from the ovary, is the primary event in the reproductive cycle that leads to a viable offspring. The physiological controls on this process are not well understood and there are increasing fertility problems due to faulty ovulation cycles in a number of agriculturally important species. Interactions with the nutritional status of the animal are increasingly being recognised as important to fertility, and in particular to embryo quality. Work in this theme is aimed at understanding the mechanisms for control of ovulation and the quality of ova released.

3.3.2 Foetal Growth and Development

The development of a viable and healthy foetus in mammalian species requires the involvement of both the mother and developing offspring. Studies included in this Theme are concerned with effects and functions within the uterus, including placental control of foetal development. The nutrition of the mother has an important influence on embryo growth and these effects are thought to be central to the programming of foetal development. This programming is believed to have effects not only on growth within the mother, but may have long term effects on post-natal development stretching into adulthood. This effect, the so-called 'Barker' hypothesis, is the subject of considerable research in humans but is also important in agricultural livestock. In humans prenatal and early life influences are believed to have a major impact on adult susceptibility to cardiovascular disease, diabetes, hypertension and obesity. Work in this Theme aims to understand the mechanisms by which these early influences have their effect.

3.4 Animal Product Quality

3.4.1 Functional Quality of Milk, Meat and Fibre

The major products from livestock agriculture in Scotland are meat, milk and fibre. The prevailing social and economic pressures are for quality products rather than volume. Work within this Theme is aimed at understanding quality with respect to both processing and sensory aspects. Research on meat links to studies in Theme 3.2.3 on muscle biology and currently has an emphasis on eating quality of red meat, processing quality in poultry meat and salmon product quality. These are areas of growing interest and importance within Scotland's food sector. In order to focus and develop expertise in these areas, in April 2002 SAC and HRI combined their facilities and expertise on food science and technology within a new centre - CHARIS Initiative. One part of this Initiative is a division of HRI, CHARIS Food Research, and the other is a commercial company jointly owned by the Scottish Agricultural College (SAC) and the Hannah Research Institute (HRI) - CHARIS Innovative Food Services Ltd. CHARIS's research is focused on producing innovative products and processes for the Scottish food industry, much of which builds on HRI's research on the chemistry of food constituents and sensory expertise. Work on fibres is aimed at improvements in the quality and yield of fine fibres from sheep and goats (cashmere), a potential area for diversification within the rural sector as sheep and goats are well suited to Scottish climatic and environmental conditions.

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