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Wang Q.,Nanjing Fisheries Research Institute
Journal of Crustacean Biology | Year: 2014

The red swamp crayfish, Procambarus clarkii (Girard, 1852) is one of the most commonly-farmed freshwater species in inland China, but the yield is very low. The aim of this study was to assess whether the gender has effect on growth performance of P. clarkii. Male and female juvenile crayfish were individually reared in net cages for 75 days (trial 1). In addition, juvenile crayfish and adult crayfish of different gender were group-reared for 60 days and 30 days respectively (trials 2 and 3). The weight growth rate (WGR, %), length growth rate (LGR, %) and survival rate (SR, %) were monitored. Results showed that the length-weight regressions differed significant between males and females juvenile crayfish (P < 0.05). Furthermore, the significant differences were noted at 60 and 75 days (P < 0.05), when body length was used as a covariate. It indicated that secondary sexual characteristics emerged when the body length reached 5.0-5.5 cm. The SR, LGR and WGR were not significantly different among juvenile crayfish gender groups, but adult male or female crayfish in mixed-sex rearing grew significantly faster than those kept in monosex rearing. A significant difference in terms of WGR (P < 0.01) (mixed-sex > females > males) was noted among monosex and mixed-sex groups. No significant difference was noted, in terms of LGR, between females and males (P > 0.05). However, the LGR of each of these was significantly lower than that of the mixed-sex groups (P <0.01). Our results demonstrated the gender has some effect on growth performance of P. clarkii, especially on adult crayfish. © 2014 The Crustacean Society.

Jiang Q.,Nanjing Normal University | Dilixiati A.,University of Sheffield | Zhang W.,Nanjing Normal University | Li W.,Nanjing Normal University | And 4 more authors.
Central European Journal of Biology | Year: 2014

The metabolic response of the freshwater prawn, Macrobrachium nipponense to nitrite toxicity was evaluated. The prawns were exposed to 0, 1, 2, 3 and 4 mg L-1 NO2-N concentrations for 48 h. The metabolic parameters in muscle were measured after 12, 24 and 48 h. Glucose level significantly increased after 24 h. Exposure to lower nitrite concentrations (1 and 2 mg L-1) resulted in significant increases in alanine aminotransferase (ALT) activities after 24 and 48 h. Aspartate aminotransferase (AST) activities treated with 2 and 3 mg L-1 nitrite-N at 48 h were significantly higher than those at 12 and 24 h. Intermediate sublethal nitrite concentrations produced significant elevations in lactate dehydrogenase (LDH) activities from 12 h up to 48 h. No significant changes were detected in any of the groups for triglycerides and creatine kinase (CK). To satisfy the increased energy demands caused by acute nitrite exposure, mobilization of lipids is not the main reason while utilization of amino acids seems to play a more important role. The results would be helpful for aquaculture farmers to prevent a potential depression of productivity caused by elevated nitrite levels. © 2013 Versita Warsaw and Springer-Verlag Wien.

Wang Q.,Nanjing Normal University | Wang Q.,Nanjing Fisheries Research Institute | Yang J.X.,Nanjing Normal University | Zhou G.Q.,Nanjing Fisheries Research Institute | And 2 more authors.
Journal of Freshwater Ecology | Year: 2011

Length-weight (body length; L B versus wet weight; W WT) and chelae length-width (L Ch versus W Ch) relationships were determined for male and female crayfish (Procambarus clarkii) under culture conditions. The length-weight relationships for males, females, and total individuals were described as W WT=0.014×L B 3:603, W WT=0.020×L B 3:350, and W WT=0.017×L B 3:467, respectively. This relationship was significantly different (p<0.001) between males and females. Compared to females, males were heavier and their tail length was shorter (p<0.001). No statistical difference was observed in mean L Ch, cheliped length (L Cp), and W Ch between the right and left sides within a gender (p>0.05), but significant differences were detected between males and females (p<0.001). The regressions for L Ch versus W Ch for males and females were W Ch=3.083×L Ch 0.847 and W Ch=0.284×L Ch 1.232, respectively. This regression differed significantly between males and females; males' chelae were wider than those of females (p<0.001). L Ch, L Cp, and W Ch were highly related to L B; males had longer L Ch and L Cp and wider W Ch than females. Individuals without chelipeds were measured to determine the relationship between the length and body weight (W BW). The L B-W BW relationships for males and females were described as W BW=0.074×L B 2.638 and W BW=0.033×L B 3.023 respectively. Females exhibited positive allometric growth (b>3), and males showed negative allometric growth (b<3). No statistical difference was observed in mean W BW between males and females when L B was used as a covariate (p>0.05). © 2011 Taylor & Francis.

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