Can crystalline arginine be used to quantify the arginine requirement of abalone?

The feasibility of using crystalline arginine in semi-purified diets to determine the quantitative arginine requirement of abalone was investigated. To this end, the assimilation efficiency of labelled [U- 14C]arginine incorporated into a formulated feed by the South African abalone, Haliotis midae, was studied. In addition, the effect of crystalline arginine supplementation on abalone growth rate was determined. The retention of [U- 14C]arginine by abalone was very low, being 11% of ingested [U- 14C]arginine. Diets supplemented with graded levels of crystalline arginine failed to produce any improvement in the growth rate of abalone. Possible reasons for the failure of crystalline arginine to boost abalone growth are discussed.