Acipenser schrenckii, the Amur Sturgeon, was a commercially valuable fish species inhabiting the Amur (Heilongjiang) River but populations have rapidly declined in recent years. Dams impede A. schrenckii spawning migration and wild populations were critically endangered. Building fishways helped maintain fish populations but data on swimming performance and behavior was crucial for fishway design. To obtain such data on A. schrenckii, a laboratory study of juvenile A. schrenckii (n = 18, body mass = 32.7 ± 1.2 g, body length = 18.8 ± 0.3 cm) was conducted using a stepped velocity test carried out in a fish respirometer equipped with a high-speed video camera at 20°C. Results indicate: (1) The counter-current swimming capability of A. schrenckii was low with critical swimming speed of 1.96 ± 0.10 BL/sec. (2) When a linear function was fitted to the data, oxygen consumption, as a function of swimming speed, was determined to be MO2  = 337.29 + 128.10U (R(2)  = 0.971, P < 0.001) and the power value (1.0) of U indicated high swimming efficiency. (3) Excess post-exercise oxygen cost was 48.44 mgO2 /kg and indicated excellent fatigue recovery. (4) Cost of transport decreased slowly with increased swimming speed. (5) Increased swimming speed led to increases in the tail beat frequency and stride length. This investigation contributed to the basic science of fish swimming behavior and provided data required for the design of fishways. Innovative methods have allowed cultivation of the species in the Yangtze River and, if effective fishways could be incorporated into the design of future hydropower projects on the Amur River, it would contribute to conservation of wild populations of A. schrenckii. The information provided here contributes to the international effort to save this critically endangered species. J. Exp. Zool. 319A:149-155, 2013. © 2013 Wiley Periodicals, Inc.

The effects of supplementation with 1.5 mM n-acetyl-l-cysteine (NAC) during in vitro oocyte maturation were studied. Oocytes were supplemented with 1.5 mM NAC during maturation for 0 to 24 h, 24 to 48 h, or 0 to 48 h then subjected to IVF and embryo development. Oocytes were evaluated after maturation for intracellular glutathione concentration, superoxide dismutase and glutathione peroxidase activities and DNA fragmentation. Fertilisation and embryonic development success were also evaluated. There was no effect of treatment on intracellular glutathione concentrations, enzyme activities or fertilisation success rates. Supplementing NAC during maturation significantly decreased (P < 0.05) the percentage of oocytes with fragmented DNA compared with no NAC supplementation. Supplementing NAC from 24 to 48 h or 0 to 48 h resulted in a significantly higher (P < 0.05) percentage of oocytes with male pronuclei than for oocytes from the other treatment groups. There was no difference in the percentage of embryos cleaved by 48 h after IVF between treatment groups. Supplementing NAC from 24 to 48 h or 0 to 48 h resulted in a significantly higher (P < 0.05) percentage of embryos reaching the blastocyst stage by 144 h after IVF compared with the other treatment groups. These results indicate that supplementation of the oocyte maturation medium with 1.5 mM NAC, specifically during the last 24 h, improves male pronucleus formation and blastocyst development in pigs.

The effects of 1.0 mmN-acetyl-l-cysteine (NAC) supplementation during the incubation of frozen-thawed and preserved boar sperm were studied in addition to subsequent oocyte IVF. Frozen-thawed and preserved boar sperm were supplemented with 1.0 mm NAC and incubated for 60 min to allow capacitation to occur followed by the addition of calcium ionophore 23187 to induce the acrosome reaction. The number of sperm having undergone the acrosome reaction was determined using the Wells-Awa staining technique. DNA damage was detected using single-cell gel electrophoresis. Membrane lipid peroxidation was estimated by the end point generation of malondialdehyde (MDA). Frozen-thawed sperm was not different in the ability of sperm to undergo the acrosome reaction but did have significantly (p < 0.05) more DNA damage (59.8 ± 1.0) compared to preserved sperm (32.0 ± 1.0%). Supplementing 1.0 mm NAC did not have an effect on the ability of sperm to undergo the acrosome reaction but did have significantly (p < 0.05) less DNA (39.2 ± 1.0%) damage compared to no antioxidant supplementation (52.7 ± 1.0%). Frozen-thawed sperm produced a significantly higher (p < 0.05) concentration of MDA (2.08 ± 0.05 μm MDA/10(7)  cells) compared to preserved sperm (1.82 ± 0.05 μm MDA/10(7)  cells), and non-supplemented sperm produced a significantly higher (p < 0.05) concentration of MDA (3.62 ± 0.05 μm MDA/10(7) cells) compared to the 1.0 mm NAC-supplemented sperm (0.28 ± 0.05 μm MDA/10(7) cells. Supplementation or semen storage method had no effect on IVF or embryonic development. These results indicate that supplementation with 1.0 mm NAC improved the ability to use frozen-thawed boar sperm during IVF as it reduces the DNA fragmentation and lipid peroxidation of the sperm.

The migration of Schizothorax prenanti, an ecologically important and commercially valuable species, is impeded by dams. Effective fishways would contribute to conservation of wild populations, and swimming performance data are necessary for fishway design. The swimming performance of S. prenanti was investigated at four temperatures (15, 19, 23, 27 °C), and numerical models were used to characterize the effect of temperature on swimming performance. As temperature increases, critical swimming speed (U crit) increases from 15 to 23 °C and then decreases significantly. The highest U crit (7.71 BL/s) occurs at 24 °C, as estimated by interpolation. Swimming efficiency was similar from 19 to 23 °C, but decreases significantly at 27 °C. The temperature range 15-23 °C is suitable for S. prenanti. However, the excess post-exercise oxygen consumption values of Q 10 for the four temperature increments indicate that 19-23 °C is the optimal range for swimming performance. Maximum tail beat amplitude increased >25 % (0.35-0.45 BL) over the temperature range considered, but variation of tail beat frequency was erratic. White muscle fiber begins to contribute to swimming at swimming speeds ~40 % U crit at the lower three temperatures, but increases to almost 60 % at 27 °C, and the contribution is relatively small. The results of this investigation advance the knowledge of fish metabolism while swimming provides data critical for fishway design.

This study evaluated the effects of anti-lipid peroxidases when supplemented to the thawing and incubation media of frozen-thawed boar spermatozoa. Semen pellets were thawed and incubated in media with 1.0 mM α-tocopherol or diethylenetriamine. After 1 h, the acrosome reaction was induced using calcium ionophore A23187, and acrosomes were evaluated using Wells--Awa staining. The number of spermatozoa with fragmented DNA was evaluated using silver staining after single-cell gel electrophoresis. Membrane lipid peroxidation was measured by the end point generation of malondialdehyde. The diethylenetriamine-supplemented media had a higher (P < 0.05) percentage of acrosome-reacted spermatozoa (84.4 ± 4.1%) compared to the control (78.3 ± 4.2%) and α-tocopherol-supplemented (78.0 ± 3.9%). The control had a higher (P < 0.05) percentage of spermatozoa with fragmented DNA (59.3 ± 4.3%) compared to the DETA (28.7 ± 4.1%) and α-tocopherol supplementation (28.0 ± 3.8%). Spermatozoa supplemented with diethylenetriamine had higher amounts (P < 0.05) of malondialdehyde generated (3.60 ± 0.05 μM/10(7) cells) compared to the α-tocopherol supplementation (0.14 ± 0.05 μM/10(7) cells) and the control (0.12 ± 0.05 μM/10(7) cells). These results indicate that supplementing with either 1.0 mM diethylenetriamine or α-tocopherol during semen thawing and incubation protects against DNA fragmentation, and diethylenetriamine increases the percent of spermatozoa capable of completing the acrosome reaction that could induce membrane lipid peroxidation.