L. Z. Zhang

Bio: L. Z. Zhang is an academic researcher from Chinese Academy of Fishery Sciences. The author has contributed to research in topics: Sturgeon & Acipenser sinensis. The author has an hindex of 6, co-authored 13 publications receiving 141 citations.

Salinity tolerance as well as osmotic and ionic regulation in juvenile Chinese sturgeon (Acipenser sinensis Gray, 1835) exposed to different salinities

Abstract: Summary To understand salinity tolerance and osmoregulatory status of juvenile Chinese sturgeon, we transferred the hatchery-reared juveniles (mean 189.9 g, 8-months-old) directly from freshwater (0) to salinity 5, 10, 15, 20, and 25 for 192 h (8 days exposure), and measured the mortality, serum osmolality and ion concentrations of fish exposed to various salinities. No mortality occurred in sturgeon exposed to salinity between 5 and 20 during the course of the trial. Sturgeons exposed to salinity 25 began to die after 12 h, and did not survive 24 h. However, acute environmental salinities 0.05). Serum osmolality and ion concentrations increased significantly (P < 0.05) in higher salinity treatments, reaching a peak at 12 h for fish in 10 and 15, and at 24 h for fish in 20 salinity. Thereafter, serum osmolality and ion concentrations decreased and reached a new steady state for fish in 10 and 15 salinity at the end of the trial, which was higher than for fish in freshwater. Serum parameters in fish exposed to salinity 20 decreased but remained unstable at 192 h, indicating a longer acclimation time was needed for fish exposed to higher salinities. The results indicate that 8-months-old juvenile Chinese sturgeon must stay in the Yangtze River estuary for a period of time to acclimate and can not move directly towards the sea. This information will help to identify the appropriate salinity where cultured juveniles can possibly be restocked.

Morphological deformities and recovery, accumulation and elimination of lead in body tissues of Chinese sturgeon, Acipenser sinensis, early life stages: a laboratory study

Abstract: Summary To determine the teratogenic effects of lead (Pb) on young Chinese sturgeon (A. sinensis), fertilized eggs (96-h) were exposed to Pb2+ until juvenile stages (total exposure 112 days). Three nominal concentrations were employed: 0.2 mg L−1, 0.8 mg L−1 and 1.6 mg L−1. After the exposure period, juveniles were returned to Pb-free water for a subsequent 42 days depuration period. Fish exposed to 0.8 and 1.6 mg L−1 Pb2+ exhibited body deformities during the exposure phase, appearing mainly as curvatures to left or right at OD (Origin of dorsal fin) to OC (Origin of the dorsal caudal fin), and OC to PC (Posterior margin of caudal fin) as well as to the OP (Origin of pectoral fin), associated with ptosis at PC. Moreover, the higher the concentration of water-borne Pb, the sooner body deformations occurred, while also affecting a larger proportion of the test individuals. Free locomotion and effective foraging was greatly reduced with increasing body deformation (lordosis). Pb accumulation in tissues was concentration dependent. Muscles accumulated relatively higher Pb which may have contributed to its effect on the muscle contraction potential and thus may have effected the neuromuscular system (muscle-induced body curvature). Morphological recovery decreased during the depuration period and this was accompanied by declining tissue Pb concentrations, indicating some self-repairing capacity.

Effect of cryopreservation on the enzyme activity of Russian sturgeon (Acipenser gueldenstaedtii Brandt & Ratzeburg, 1833) semen

Abstract: Summary The hypothesis was tested that cryodamage occurs during the storage of semen at −196°C and that cryopreservation has a negative effect on the enzyme activity and motility of semen in the Russian sturgeon, Acipenser gueldenstaedtii. In addition, the aim of the study was to determine the activity of metabolic enzymes, including adenosintriphosphatase (total ATPase), creatine kinase (CK), succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH), plus antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR). After cryopreservation (storage at −196°C), the motility and duration of semen fell and the total ATPase, SDH, LDH and CK activity in the spermatozoa was reduced. In the seminal plasma, however, total ATPase, SDH, LDH and CK activity increased markedly. Activity also notably increased in the group with no diluents or cryoprotectants. SOD, CAT and GSH-Px activities also increased in the seminal plasma but dropped with regard to the spermatozoa, whereas the GR activity varied. The antioxidant enzyme activity trend between the groups with and without the addition of cryoprotectants was the same as in the metabolic enzyme activity. Cryopreservation had a great effect on the enzyme activity and motility of A. gueldenstaedtii semen; however, the cryoprotectant protected the semen during cryopreservation.

Isosmotic points and their ecological significance for juvenile Chinese sturgeon Acipenser sinensis

Abstract: Serum osmolality and ion concentrations were measured in juvenile Chinese sturgeon Acipenser sinensis at different salinities to determine the isosmotic point. Isosmotic and isoionic concentrations were calculated from the regressions for serum and ambient osmolality, with Na(+) , Cl(-) and K(+) as salinities 9·19, 8·17, 7·89 and 9·70, respectively. These values were consistent with the salinity of the habitat where juvenile A. sinensis occur in the Yangtze Estuary, suggesting that an isosmotic salinity is an important factor driving their habitat choice.

Use of Fish as Bio-indicator of the Effects of Heavy Metals Pollution

Abstract: The present review gives a brief account of the toxic effects of heavy metals on fish. In aquatic ecosystem, heavy metals are considered as the most important pollutants, since they are present throughout the ecosystem and are detectable in critical amounts. Heavy metals, such as mercury, cadmium, copper, lead and zinc are of the most important pollutants which effect aquatic environment and fish. They are extremely dangerous for the health of fish. Most of these metals are characterized by being accumulated in tissues, and lead to the poisoning of fish. These metals can effectively influence the vital operations and reproduction of fish; weaken the immune system, and induce pathological changes. As such, fish are used as bio-indictors, playing an important role in monitoring heavy metals pollution. Finally, some recommendations are given to treatment of different kinds of wastewaters, sewage and agricultural wastes before discharge into the aquatic systems. Also, enforcement of laws and legislations regarding the protection of aquatic environments must be taken into consideration.

Tissue Distribution and Whole Body Burden of the Chlorinated Polyfluoroalkyl Ether Sulfonic Acid F-53B in Crucian Carp (Carassius carassius): Evidence for a Highly Bioaccumulative Contaminant of Emerging Concern.

Abstract: Following the global actions to phase out perfluoroctanesulfonic acid (PFOS) a large number of alternative per- and polyfluoroalkyl substances, with poorly defined hazard properties, are being used in increasing quantities. Here, we report on the first detection of the chlorinated polyfluoroalkyl ether sulfonic acid F-53B in biological samples and determine the tissue distribution and whole body bioaccumulation factors (BAFwhole body) in crucian carp (Carassius carassius). Analysis of fish samples from Xiaoqing River (XR) and Tangxun Lake (TL) demonstrated a similar level of F-53B contamination with median concentrations in blood of 41.9 and 20.9 ng/g, respectively. Tissue/blood ratios showed that distribution of F-53B primarily occurs to the kidney (TL: 0.48, XR: 0.54), gonad (TL: 0.36, XR: 0.54), liver (TL: 0.38, XR: 0.53), and heart (TL: 0.47, XR: 0.47). Median Log BAFwhole body values for F-53B (XR: 4.124, TL: 4.322) exceeded regulatory bioaccumulation criterion and were significantly higher than thos...

Chemical composition and nutritional quality of sea cucumbers

Abstract: BACKGROUND: The dried form of sea cucumbers has been a seafood and medicinal cure for Asians over many centuries. In this study the chemical composition and nutritional quality of eight common sea cucumbers (Stichopus herrmanni, Thelenota ananas, Thelenota anax, Holothuria fuscogilva, Holothuria fuscopunctata, Actinopyga mauritiana, Actinopyga caerulea and Bohadschia argus) were determined. RESULTS: All species except T. anax and A. caerulea had higher protein and lower fat levels. A. mauritiana and B. argus had less ash content. Glycine was the dominant amino acid found in all species, and content ranged from 126 to 216 mg g(-1) of crude protein. All species exhibited low lysine : arginine ratio and higher essential amino acid scores were obtained by threonine and phenylalanine + tyrosine. A. mauritiana had proportionally less saturated fatty acids (31.23%), and more monounsaturated fatty acids (45.64%) and polyunsaturated fatty acids (PUFA, 23.13%) than other species. Arachidonic acid (C20 : 4n-6) was the major PUFA in all species. T. ananas, A. mauritiana and A. caerulea contained more n-3 PUFA. The n-3/n-6 ratios of eight sea cucumbers species ranged from 0.25 to 0.61. CONCLUSION: Sea cucumbers are a seafood with high protein and low fat levels. The amino acid contents were similar but fatty acid profiles were different among species. The comparison showed that T. ananas, A. mauritiana and B. argus possessed higher nutritional values than other sea cucumber species. (c) 2010 Society of Chemical Industry