INTRODUCTION
The concept of bioavailability, which is usually defined as the proportion of a nutrient that is utilized by animals for normal body functions, is fairly simple. However, as stated by Fairweather-Tait (1992) the problems arise in its determination. Consequently, many nutritionists amend the above definition to include the proportion of a nutrient absorbed that can be utilized (Bender, 1989; Ammerman et al, 1995). Tissue accumulation of a mineral meets the latter definition, but not the former.