Effects of animal size and nutritional status on the RNA/DNA ratio in different tissues of the green-lipped mussel Perna viridis

Abstract

This study aimed to examine the responses of RNA/DNA ratio in Perna viridis under different nutritional status via both field and laboratory studies, and hence evaluate the usefulness of this ratio as a rapid growth biomarker in the mussels. First, the effects of size (small: 30-40 mm; medium: 40-50 mm; large: .50 mm) and tissue type (adductor muscle, foot, gill and hepatopancreas) on the RNA/DNA ratio were investigated in P. viridis collected from three different sites with different degrees of eutrophication in Hong Kong waters. Across all sizes, the mussels collected from a fairly 'eutrophic' mariculture zone had significantly higher RNA/DNA ratios in their gills than those from the other two relatively clean sites. The RNA/DNA ratio in small mussels was generally higher than in medium and large individuals, though such a size effect significantly interacted with tissue type and site. Second, we conducted a 10-day comparative laboratory study to elucidate the influence of starvation and feeding on the RNA/DNA ratio in the mussels. We observed that both hepatopancreas and foot muscle generally exhibited significant and rapid response to such a short-term starvation or food addition. The present results confirmed that the RNA/DNA ratio in P. viridis is a sensitive biomarker to gauge their growth and general health condition in accordance with food availability and/or eutrophication condition.

Microscopic Imaging to Visualize the Distribution of Dietary Nucleic Acids in Food Products of Various Origins

“…In particular, it would inevitably lead to the degradation of RNA that may be contained in food samples, as it has been suggested that in some food products, RNA content is higher than DNA content. For instance, some scientific reports showed that RNA content in seafood could be more than four times the amount in DNA [4,5]. Therefore, RNA losses can cause significant misrepresentation in estimated nutritional value associated with the content of dietNAs in a given food product.…”