Effects of salinity on gonadal development, osmoregulation and metabolism of adult male Chinese mitten crab, Eriocheir sinensis

Abstract

As a catadromous species, salinity is a key parameter that affects gonadal development of Chinese mitten crab Eriocheir sinensis during reproductive migration. It is however unclear the effects of salinity on the gonadal development of male E. sinensis as well as their physiological responses to salinity during reproductive migration. This study investigated the effects of four salinities (0 ‰, 6 ‰, 12 ‰ and 18 ‰) on gonadal development, osmoregulation and metabolism of adult male E. sinensis over a 40-day period. The results showed that elevating salinity promote gonadal development, increase hemolymph osmolality and K+ and Mg2+ concentrations (P < 0.05). The 12 ‰ salinity resulted in the highest contents of taurine and arginine in the hemolymph while the highest contents of threonine, phenylalanine, lysine, ß-alanine, tryptophan, ornithine and total free amino acids were found for 0 ‰ treatment (P < 0.05). A decreasing trend was detected for the Na+/K+-ATPase activity and its mRNA expression level in the posterior gills with salinity (P < 0.05). Total saturated fatty acids in the anterior gills decreased with increasing salinity (P < 0.05); the 0 ‰ treatment had the highest total polyunsaturated fatty acids in the posterior gills while total n-6 polyunsaturated fatty acids increased with salinity (P < 0.05). The hemolymph glucose and uric acid showed a decreasing trend as salinity while an increasing trend was found for the hemolymph triglyceride and high-density lipoprotein cholesterol (P < 0.05). The 12 ‰ treatment had the highest levels of hemolymph malonaldehyde and hepatopancreatic γ-glutamyltranspeptidase (P < 0.05). In conclusion, these results suggested that the brackish water promote gonadal development of male E. sinensis, and increase osmolality and ionic concentrations in hemolymph while reduced the activity of Na+ /K+- ATPase and its mRNA expression in the posterior gills as well as metabolism.

Physiological Responses and Ovarian Development of Female Chinese Mitten Crab Eriocheir sinensis Subjected to Different Salinity Conditions

“…All crabs were treated with cold shock method to minimize suffering, then around 2 mL hemolymph was withdrawn from each crab sample by inserting a 1.0 mL syringe at the base of the third walking leg and all hemolymph samples were stored at −40°C for later analysis. It is known that E. sinensis has six pairs of gills, previous studies have shown that the first 3 pairs of the gills (pairs 1–3, also known as anterior gills) are responsible for respiration while pairs 4–6 of gills (posterior gills) are specified for osmoregulation (Long et al, 2017b ). Therefore, in this study, the pairs 5 posterior gills were sampled and snap frozen in liquid nitrogen and stored at −80°C for the Na + /K + -ATPase activity and its mRNA expression analysis.…”

“…As such, there are likely gender differences in physiological responses to salinity changes during reproductive migration and gonadal development, which necessitates studies on salinity effects on gonadal development of E. sinensis being carried out separately for males and females. Our recent studies have reported the effects of long-term salinity adaptation on gonadal development, osmoregulation and metabolism of adult male E. sinensis (Long et al, 2017b ), however it remains unknown the physiological responses and ovarian development of female E. sinensis subjected to different salinity conditions. Therefore, the present study comprehensively investigated the effects of long-term exposure to different salinities on ovarian development, hemolymph osmolality and major ion as well as free amino acid concentrations, gill Na + /K + -ATPase activity and fatty acids profile, as well as a range of metabolic and antioxidant indices in hemolymph and hepatopancreas of the female E. sinensis following puberty molt.…”

Effects of dietary fish oil replacement with blended vegetable oils on growth, lipid metabolism and antioxidant capacity of subadult swimming crabPortunus trituberculatus

“…A total of eight crabs were randomly sampled from each treatment and weighted using a digital balance (precision = 0.01 g). According to the method of Long, Wu, Zhao, Ye, et al (), all crabs were treated with cold shock method to minimize suffering, and then around 3 ml haemolymph was withdrawn by inserting a syringe at the base of the fourth walking limb of each crab and stored in two 2‐mL tubes at −80℃ for later analysis of antioxidant and immune indices. The hepatopancreas and muscle from each crab were carefully dissected out and weighted separately before stored at −40℃ for later biochemical analysis.…”

Relationship Between Stage of Gonad Maturity and Level of Osmotic Work of Sea Cucumber, Paracaudina australis

“…However, studies of isosmotic media in other invertebrates have been conducted as the results of Anggoro and Muryati (2007) showed that salinity of the osmotic medium significantly affected Ca-chorionase enzyme activity, energy efficiency and efficiency of egg hatching Metapenaus elegans. Another research showed that salinity fluctuation greatly affected the development of male gonads crab Eriocheir sinensis, increasing osmolarity and ionic concentration in hemolymph (Long et al, 2017). …”