Comparison of three inert markers in measuring apparent nutrient digestibility of juvenile abalone under different culture condition and temperature regimes

A comparative research using three inert markers, chromic oxide, yttrium and ytterbium to measure the apparent nutrient digestibility of experimental feed in juvenile Hybrid abalone (Haliotis rubra X H. laevigata) and Greenlip abalone (H.laevigata) revealed that apparent digestibility of crude protein (ADCP) measured using yttrium and ytterbium in hybrid abalone were significantly different across the treatments. Protein digestibility measured in experimental tanks was higher than those measured in indoor and outdoor commercial tanks, regardless of inert marker used. Chromic oxide led to overestimated AD_CP compared to when measured using yttrium and ytterbium. There were no significant interactions between temperature and inert markers when measuring AD_CP and apparent digestibility of gross energy (AD_GE). However, there was a significant difference of AD_CP amongst inert markers when measured in greenlip abalone cultured at two temperatures. While measurements of AD_GE calculated using three inert markers shared the same value.