Livestock Production Science, 17, (1987) 187-188 187 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

Book Review

FOOD INTAKE

The Voluntary Food Intake of Farm Animals. J.M. Forbes, The Butterworth Group, Borough Green, Sevenoaks, Kent, TN15 8P, U.K., 1986 206 pp., price £ 29.50, ISBN 0-408-111542.

This book is organized in 3 main parts: the definition and methods of mea- surement of food intake, the control mechanisms, and the quantitative changes and prediction of intake.

After discussing the definition and significance of voluntary food intake, the author describes the methods of measuring the different components of food intake and the meal pattern according to animal species, and he stresses the importance of predicting and manipulating food intake in farm animals.

The controlling mechanisms of food intake are reviewed by considering sin- gle-factor theories (gastric distension, glucostatic, thermostatic and lipostatic controls) and multifactor theories (energostatic control with the specific con- tribution of the liver, sensory factors and the integration of multiple feed- backs), to end with a quantitative integration of food intake by means of mathematical models. A special emphasis is placed on the negative feedback pathways (oropharyngeal, gastrointestinal and liver receptors, metabolites and hormones) which contribute in a cumulative way to the multifactorial control of food intake through the central nervous system. The central nervous control is fully described in a further section, through lesioning studies, injection of anaesthetics and neurotransmitters and through brain peptides.

The third part of the book deals with the quantitative prediction and control of food intake in the different farm animals. As a first step, there is an assess- ment of quantitative changes in food intake with age and live weight, according to the physiological status (maintenance, growth and reproduction). The di- etary factors involved in the adjustment of food intake are considered in the next section: they include digestibility and energy concentration, protein and amino acid levels, specific appetites for minerals and amino acids, fasting, fre- quency of feeding and sensory factors, as well as water intake. Specific effects of environmental factors on intake are reviewed: these include environmental temperature (cold and hot environments), photoperiod, social factors, hous- ing and disease. A special chapter is devoted to the intake of fresh and con- served grass in ruminants (intake of pasture, hay and silage, and also factors of variation). The prediction of voluntary intake in ruminants, pigs and poul- try is described through single and multiple regression equations, taking into account predictors related to physical limitation (digestibility and gut capac- ity) and metabolic control of intake, along with production performance. Finally

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the author gives the available information on different ways of manipulating food intake, through dietary modifications (energy concentration or supple- mentation of forage with concentrate feeds) or by using feed additives, hor- mones and anabolic agents.

The original contribution of this book is to provide a new review of food intake control in the different farm animals (ruminants, pigs and poultry), by considering the basic control mechanisms and the quantitative aspects of pre- diction of intake at the same time. In each chapter the specific features for the different animal species are developed, although more emphasis is put on ru- minants than on poultry and pigs. The recent findings on food intake regula- tion, especially in pigs, should be updated.

As far as presentation is concerned, the reading is sometimes made more difficult by providing series of factual research findings without an overall syn- thetic personal view. Nevertheless, the summary at the end of each chapter is helpful for drawing general conclusions. The book ends with an extensive list of references, although some recent ones are lacking. This is followed by a comprehensive index, but some keywords representative of food intake are missing. To conclude, the book provides useful and valuable information on control mechanisms and prediction of food intake in farm animals, especially in ruminants.

Y. HENRY Station de Recherches Porcines,

INRA - Centre de Rennes-St GiUes, F 35590 L'Hermitage,

France