| Different salinity and alkalinity were set up to determine the sperm sperm motility,fertilization rate, hatching rate, deformity rate of the embryos, and 24, 48 h survival rate of newly hatched larvae of Songpu mirror carp(Cynipus carpio), Gibel carp(Carassius auratus gibelio) and Barbus capito. In addition, the complex influence of salinity and alkalinity on the sperm motility, fertilization rate, hatching rate and deformity rate of the embryos of Barbus capito were investigated. These may provide basic data for the exploitation and development of fisheries in carbonated saline waters in North China.1. Effects of Na Cl salinity and Na HCO3 alkalinity on the sperm motility and fertilization rate of Cynipus carpio, Carassius auratus gibelio and Barbus capitoInfluence of different salinity(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) and alkalinity(0mmol/L, 10.00 mmol/L, 15.85 mmol/L, 25.12 mmol/L, 39.81 mmol/L, 63.10 mmol/L)on the sperm motility and fertilization rate of Songpu mirror carp(Cynipus carpio),Gibel carp(Carassius auratus gibelio) and Barbus capito were investigated in this study.The result showed that ①The drastic movement time, rapid movement time and life span of the sperm of Gibel carp and Barbus capito were the longest when the salinity was 4, and the duration of Gibel carp sperm were(90.11±9.03) s,(126.34±13.90) s and(154.27±11.36) s, respectively; while the duration of sperm in Barbus capito were(48.91±1.43) s,(62.19±4.28) s and(90.68±4.46) s, respectively. The drastic movement time, rapid movement time and life span of the Songpu mirror carp sperm were the longest at the salinity of 5, and they were(72.44±9.42) s,(102.16±8.82) s and(206.99±6.65) s, respectively. ② When the salinity was greater than 8, the initiation of thesesperm of the three fishes were all inhibited. When the salinity was greater than 10, the sperm of Gibel carp and Barbus capito were dead, and when the salinity was greater than 11, the sperm of Songpu mirror carp was dead. ③ For alkalinity, at alkalinity of15.83 mmol/L, the drastic movement time, rapid movement time and life span of the three fishes were the longest, and the sperm motility were significantly greater than other alkalinity groups(P<0.05). ④ The fertilization rate of Gibel carp and Barbus capito were the highest at salinity of 1, and they were 63.0% and 68.0%, respectively.The fertilization rate of Songpu mirror carp was 72.3% at salinity of 3, which was the highest among all salinities. At alkalinity of 10.00 mmol/L, the fertilization rate of the three fishes reached the highest, which were 75.4%, 54.0% and 66.0%, respectively.Consequently, the effects of salinity and alkalinity on the sperm motility and fertilization rate of the three fishes were obtained in present study.2. Effects of Na Cl salinity and Na HCO3 alkalinity on hatching rate and larval vitality of Songpu mirror carp and Gibel carpInfluences of different Na Cl salinity(0, 1, 3, 5, 7, 9) and Na HCO3 alkalinity(1mmol/L, 10.00 mmol/L, 15.85 mmol/L, 25.12 mmol/L, 39.81 mmol/L, 63.10 mmol/L)on hatching rate, deformity rate of the embryos, and 24, 48 h survival rate of newly hatched larvae of Songpu mirror carp(Cynipus carpio L.) and Gibel carp(Carassius auratus gibelio Bloch) were investigated in this study. ①The results of the experiments about salinity showed that the high hatching rates of Songpu mirror carp were observed when the salinity ranged from 0 to 1,which was 72.40% ± 6.09% on average. The deformity rates of Songpu mirror carp were lower obviously at salinities 0to 3 than other groups, and the mean deformity rate was 6.02% ± 1.87%, meanwhile, the mean 48 h survival rate was 94.99% ± 6.44%. For Gibel carp, high hatching rates were observed at salinities from 0 to 3, which was 68.03% ± 15.44% on average. The deformity rates of Gibel carp were low obviously at salinities 0 to 5, and the mean deformity rate was 7.95% ± 3.24%, meanwhile, the mean 48 h survival rate reached88.52% ± 9.19%(Fig.1). ② The results of the experiments about alkalinity showed that the high hatching rate of these two fishes were observed when the alkalinity ranged from 1~25.12 mmol/L, and it was 47.96% ± 8.43% for Songpu mirror carp and 66.23%± 18.11% for Gibel carp on average. The deformity rates of these two fishes were lower significantly when the alkalinity ranged from 1 to 15.85 mmol/L, and it was 12.47% ±3.77% for Songpu mirror carp and 12.46% ± 8.44% for Gibel carp on average. When the alkalinity ranged from 1 to 15.85 mmol/L, the mean 48 h survival rate of Songpu mirror carp was 96.16% ± 5.04%, and the mean 48 h survival rate of Gibel carp was85.62% ± 3.73%(Fig.2). In conclusion, for Songpu mirror carp and gibel carp, the suitable salinity for the hatch of fertilized eggs and the survival of larvae should be lower than 3, and the suitable alkalinity should be lower than 15 mmol/L.3. Combined effect of salinity and alkalinity on sperm motility,fertilization rate, hatching rate and deformity rate of Barbus capitoWe evaluated the combined effects of salinity and alkalinity on the sperm motility(drastic movement time, rapid movement time and life span of the sperm), fertilization rate, hatching rate and deformity rate of Barbus capito. We used a two-factor central composite experimental design. The results showed that the linear effects and the quadratic effect of salinity and alkalinity had significant effect on the drastic movement time and rapid movement time of sperm(P<0.05). The linear effects and the quadratic effect of salinity had significant effect on the sperm span(P<0.05), the quadratic effect of alkalinity had significant effect on the sperm span(P<0.05). The interaction between salinity and alkalinity was not associated with changes in sperm motility of Barbus capito(P>0.05). By means of optimizing the equation of the model, we found that when the salinity was 2.83 ppt and the alkalinity was 10.59 mmol/L, the sperm motility was the strongest, and the drastic movement time, rapid movement time and life span of the sperm were 46.11 s, 70.90 s and 90.26 s, respectively, the reliability was 76.4%.The linear effects, the quadratic effects of salinity and alkalinity and the interaction between salinity and alkalinity were not associated with changes in fertilization rate of Barbus capito(P>0.05). The linear effects and the quadratic effects of salinity had significant influence on the hatching rate of Barbus capito(P<0.05). And the linear effects and the quadratic effects of alkalinity were not associated with changes in hatching rate of Barbus capito(P>0.05). The interaction between salinity and alkalinity was not associated with changes in hatching rate of Barbus capito(P>0.05). The linear effectsand the quadratic effects of salinity was not associated with changes in deformity rate of Barbus capito(P>0.05). The interaction between salinity and alkalinity had significant influence on the deformity rate of Barbus capito(P<0.05).By means of optimizing the equation of the model, we found that when the salinity was 2.87 ppt and the alkalinity was 4.50 mmol/L, the hatching rate was the highest(65.86%) and the deformity rate was the lowest(19.32%), and the reliability was 59.50%. These may provide the best combination of salinity and alkalinity for the artificial breeding of Barbus capito. |
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