Osmoregulation in juvenile Chinese sturgeon (Acipenser sinensis Gray) during brackish water adaptation

Abstract

The osmoregulation capabilities of 7-month-old juvenile Chinese sturgeon (Acipenser sinensis Gray) (128.8 +/- 15 g) transferred directly from fresh water (0 per thousand, 46 mOsmol kg(-1)) to brackish water (10 per thousand, 273 mOsmol kg(-1)) were studied over a 20-day period. Changes in serum osmolarity, chloride (Cl(-)), sodium (Na+), potassium (K+) and calcium (Ca2+) ion concentrations, as well as gill and spiral valve Na+,K+-ATPase activities were measured at 3, 12, 24, 72, 216 and 480 h after transfer to BW. The serum osmolarity and ion concentrations (Na+, Cl(-) and Ca2+) increased immediately after the transference to BW, reaching maximum at 24 h and returned to a new steady state at 216 h, while the FW control group maintained basal levels which showed lower (P < 0.05) than the BW group. Gill Na+,K+-ATPase activity of BW group exhibited an abrupt decrease in the first 3 h after transfer, but began to increase at 3 h, reaching a peak value at 24 h, and returned to a new steady state at 216 h. The differences between gill Na+,K+-ATPase activity of BW and FW fish were significant (P < 0.05) after 12 h. In contrast, Na+,K+-ATPase activity of the spiral valve showed transient increase after transference from FW to BW, and then decreased rapidly at 3 h, reaching the lowest at 24 h after transference. At 216 h after exposure to BW, Na+,K+-ATPase activities of the spiral valve increased slowly to the levels of FW control. The results of our study indicate the existence of hyposmoregulatory adaptive mechanisms in 7-month-old juvenile Chinese sturgeon which enable this fish to acclimate itself successfully to brackish water.

Adaptive alterations on gill Na+, K+-ATPase activity and mitochondrion-rich cells of juvenile Acipenser sinensis acclimated to brackish water

“…As has been observed previously by He et al (2009) and Zhao et al (2011, 2015, juveniles of this age/size class were able to acclimate to salinities greater than FW. In the present study, serum osmolality was significantly increased in sturgeon acclimated to BW, relative to those in FW (Table 1).…”

Physiological characteristics and stress resistance of great sturgeon (Huso huso) juveniles fed with vitamins C, E, and HUFA-enriched Artemia urmiana nauplii

“…The same effects were observed in the Chinese sturgeon (Acipenser sinensis; He et al 2008) and A. oxyrinchus (Altinok et al 1998). In conclusion, the data resulting from this study showed that the enrichment of A. urmiana with essential fatty acids in combination with vitamins E and C may have some influence on the physiological parameters and stress resistance of beluga (H. huso) juveniles.…”

Salinity effects on osmoregulation and gill morphology in juvenile Persian sturgeon (Acipenser persicus)

“…For some sturgeon species, blood plasma osmolality increases when fish are transferred from FW to BW or SW Allen and Cech 2007;Zhao et al 2011;Allen et al 2014) and usually rapidly returns to initial values or even values that are below medium osmolality (Jarvis and Ballantyne 2003;Martinez Alvarez et al 2005;He et al 2009). For species that cannot adapt to elevated salinity, plasma osmolality remains high (Rodriguez et al 2002;Sardella and Kültz 2009;Allen et al 2011).…”

“…A suite of morphological and functional changes occurs in the osmoregulatory structures, enabling constant ion and osmotic homeostasis as fish move from hypo-to hyperosmotic salinities, or reversely (Marshall and Grosell 2006;He et al 2009;McCormick et al 2009). In teleosts, the number of branchial chloride cells, their shape and expression level of ion transport proteins involved in salt secretion have been shown to be adjusted according to salinity (McCormick et al 2009).…”