Studies on the physiology of a shrimp, Metapenaeus mastersii (Haswell) (Crustacea: Decapoda: Peneidae). I. Blood constituents

Abstract

Three cell types were distinguished: a thigmocyte, a lymphocyte-like cell, and a granular amoebocyte, the latter forming and transporting polysaccharides. Plasma was hypotonic at 35‰ salinity, isotonic at 22‰, and hypertonic below this. Concentrations of Na⁺, K⁺, and Cl^- varied in a broadly similar fashion. Ca²⁺ was higher than that of the external in all cases, and by calculation Mg²⁺ was reduced at higher salinities. Dialysis showed that all ions were actively regulated. Glucose 6-phosphate, a trace of another ester (probably fructose 6-phosphate), glucose, a nucleotide, and glucosamine, probably from mucoproteins, were identified by paper chromatography. Blood total reducing substances were increased by feeding and reduced by starvation, due to low reserves and the necessity for constant feeding to maintain blood sugars. Total protein ranged from 1.9 to 4.5%, non-protein nitrogen from 13 -7 to 25.3 mg%. Starch gel electrophoresis resolved four protein bands, the densest being haemocyanin, the next, mucoprotein.