There is a continuing requirement to improve the lean content of meat, efficiently produced, as food for human consumers. Hormonal anabolic compounds which stimulate the deposition of lean tissue and reduce fat accretion in ruminant animals are not permitted in the UK. In the absence of the use of such exogenous compounds, alternative currently practical means of manipulating body composition include the use of genetic selection and alterations in nutrition. The objective of the present study was to investigate the effect of diets differing in the source of carbohydrate and in protein level. The diets chosen were based on barley (diet B) in which starch predominates and sugar beet pulp (diet P) which contains greater quantities of cellulose and hemi-cellulose.

Twenty-eight crossbred (Suffolk ♂ x mule ♀ )entire male lambs were used in the experiment. They were housed at approximately eight weeks of age in individual slatted-floor pens and gradually introduced to experimental diets over a period of three weeks prior to the commencement of the study. Four pelleted diets were offered.