Carbonic anhydrase and Na/K-ATPase activities during the molt cycle of low salinity-reared white shrimp Litopenaeus vannamei

Abstract

Changes in hemolymph osmolality, ion concentrations, and enzymatic activities of carbonic anhydrase (CA) in the gills and epidermal tissue, and Na/K-ATPase in the gills during the molt cycle were investigated in the white shrimp Litopenaeus vannamei. Hemolymph osmolality was high in the intermolt and early premolt stages, but started to decrease prior to ecdysis through to postmolt stages A and B. Changes in Na ? and Cl -ion concentrations paralleled those in hemolymph osmolality. CA activity levels in the anterior and posterior gills were low at intermolt stage C 0 and premolt stage D 0 , and maximum at premolt stage D 3 . In the epidermal tissue, activity was relatively high at intermolt stage C 0 and premolt stage D 0 , but fluctuated towards premolt stage D 3 and postmolt stage A. On the other hand, Na/K-ATPase activity in the gills decreased between intermolt stage C 0 and premolt stage D 2 , but increased at premolt stage D 3 and postmolt stage A. The changes in patterns of CA activity during the molt cycle suggest that CA may be involved in supplying counter-ions for Na ? and Cl -uptake during molting. Branchial Na/K-ATPase appears to be involved in producing local osmotic gradients in order to support water influx across the epithelium.

Molecular cloning and expression of hepatopancreas glutamine synthetase in the Pacific white shrimp, Litopenaeus vannamei, induced by acute hypo-osmotic stress

“…Salinity stress is one of the most important environmental stresses that severely limit the survival and productivity of L. vannamei. L. vannamei is capable of tolerating a wide range of ambient salinities from 0.5 ppt to 40 ppt (Bray et al, 1994;Jasmani et al, 2010). The osmoregulatory mechanism is important for the natural life cycle of shrimp and also for shrimp farming (Kaeodee et al, 2011).…”

A transcriptomic scan for potential candidate genes involved in osmoregulation in an obligate freshwater palaemonid prawn (Macrobrachium australiense)

“…Transcript lengths ranged from 218–3,027 bp. This enzyme constitutes one of the primary components of the osmotic regulation, is highly expressed in the organs that are responsible for osmotic and ionic regulation ( Jasmani et al, 2010 ; Jasmani, Jayasankar & Wilder, 2008 ; Roy et al, 2007 ).…”

Moulting in the grow‐out of farmed shrimp: a review

“…Haemolymph calcium is reported to increase in premoult and decreases subsequently in post-moult (Ferraris et al, 1986), while magnesium decreases from D0 to A (Jasmani et al, 2010). Haemolymph calcium and magnesium levels may increase by absorption from water, resorption from the old exoskeleton and by active feeding (Mugnier & Justou, 2004).…”

“…Haemolymph calcium and magnesium levels may increase by absorption from water, resorption from the old exoskeleton and by active feeding (Mugnier & Justou, 2004). The dynamics of mineral levels obviously depend on medium salinity; active ion transport is higher in shrimp reared in low salinity as checked with Na/K ATPase activity reaching greatest values between D3 and B (Jasmani et al, 2010).…”