缢蛏与近江蛏种间杂交子代高盐耐受性分析OA

This study analyzed the salinity tolerance,physiological metabolism,and associated enzyme activities of hybrid offspring of Sinonovacula constricta and S.rivularis under high salinity stress.The survival rates in the CR(S.constricta♀×S.rivularis♂),RC(S.rivularis♀×S.constricta♂),CC(S.constricta♀×S.constricta♂),and RR(S.rivularis♀×S.rivularis♂)groups were measured under different salinity gradients,from which the semi-lethal concentrations were calculated.Dynamic changes in oxygen consumption rate,ammonia excretion rate,feeding rate,and key osmoregulatory enzymes,i.e.,Na+-K+-ATPase(NKA),carbonic anhydrase(CA),and V-H+-ATPase(VHA),were evaluated across different salinity levels,ranging from 23 to 30.The semi-lethal salinities at 96 h for the CR,RC,CC,and RR groups were 31.08,28.83,35.61,and 21.76,respectively.The physiological parameters(i.e.,oxy-gen consumption rate,ammonia excretion rate,and feeding rate)followed a decreasing trend as salinity increased from 23 to 30.The physiological parameters in both reciprocal hybrid groups were significantly higher than those in S.constricta(P<0.05),indicating the notably higher metabolic capacity of the hybrids.Owing to the significant differences observed in physiological metabolism across salinities,enzyme activities were evaluated at salinities of 25 and 30.During prolonged stress,NKA and CA activities first increased,then decreased,and finally remained stable after 96 h in the CR,RC,and CC groups.At salinity 25,NKA and CA activities were significantly higher in the CR and RC groups than in the CC group(P<0.05);in contrast,at salinity 30,NKA and CA activities were sig-nificantly lower in the CR and RC groups than in the CC group(P<0.05).VHA activity was similar among the CR,RC,and CC groups,exhibiting an initial decrease followed by an increase over the stress period.In summary,our results indicate that hybrid offspring exhibit higher metabolic capacity below salinity 27(P<0.05).However,at salinity 30,the osmoregulatory and metabolic capacities of the hybrids were significantly reduced(P<0.05).This study provides a theoretical foundation for shaping aquaculture practices of hybrid clams and for understanding the physiological mechanisms underlying salinity tolerance,offering valuable insights for breeding new strains of S.constricta with high salinity tolerance.