下潜养殖系统中不同规格气泡对虹鳟补气效果的影响

DIFFERENT SIZES OF BUBBLES ON AIR SUPPLY OF RAINBOW TROUT IN SUBMERGED CULTURE SYSTEM

为探究不同规格气泡对下潜养殖虹鳟生长、行为、能量收支、抗氧化能力和体形态的影响,试验设置5个不同处理组:对照组(不增加网罩和补气设备)、无气泡组(水中增加网罩隔离)和3种气泡组(水中增加网罩隔离,并在网罩下方添加3种规格的气石,气泡直径分别为1.02、0.33和0.11 cm)。经过28d的养殖实验,结果显示大、中气泡组虹鳟的末体重和特定生长率显著高于小、无气泡组,鱼鳔体积和鱼鳔产生的浮力均显著大于小、无气泡组,这表明大、中气泡有效地补充了虹鳟鱼鳔内的气体,恢复了其生长性能。气泡组虹鳟的SOD和CAT活力显著低于对照组,且MDA和LPO显著降低,表明下潜胁迫对其机体抗氧化系统造成一定的损伤;但大、中气泡组虹鳟抗氧化指标的IBR_(v2)较小、无气泡组更接近对照组,表明其在一定程度能缓解下潜养殖的负面效应。气泡组虹鳟身体的“流线型”高于对照组,且鳍和尾部的相对面积增大,这可能是虹鳟应对浮力缺失的改善措施。综上,由于较大气泡更容易被虹鳟吞食,且更易于在食道中聚集,经鳔管压缩进入鱼鳔,因此,大、中气泡具有更强的补气效果来缓解下潜养殖鲑鱼负浮力的胁迫。

Submerged cage culture represents an effective solution to challenges posed by high temperature,typhoon,and fish lice infection in open sea aquaculture.However,it leads to the adverse effects on physostomous fish like salmon such as gas loss in the swim bladder,slow growth,skeletal deformity,and high mortality.In order to investigate the effects of different bubbles sizes on the growth,behavior,energy budget,antioxidant capacity and body morphology of submerged rainbow trout(Oncorhynchus mykiss),this experiment established five groups with different aquaculture equipments as follows:the control group(without mesh and air supply device),the no-bubble group(adding mesh for isolation)and the three bubble groups(adding mesh for isolation and three kinds of air stone under the mesh for air supplement,with bubble diameter of 1.02,0.33 and 0.11 cm,respectively).After a 28-day trial,the results showed that the final body weight and specific growth rate of rainbow trout in the large and medium bubble groups were significantly higher than those in the small and no bubble groups.The swim bladder volume and buoyance generated by swim bladders of rainbow trout in the large and medium bubble groups were significantly greater than those in the small and no bubble groups.These indicate that the large and medium bubbles effectively supplemented gas in the swim bladder of rainbow trout and restored its growth.The activities of SOD and CAT of rainbow trout in the bubble group were significantly lower than those in the control group,and MDA and LPO were significantly decreased,indicating that the anti-oxidation system of rainbow trout was damaged by diving stress.However,the IBR_(v2) of the antioxidant index of rainbow trout in the large and medium bubble groups was closer to the control group than the small and the non-bubble group,indicating that it could alleviate the negative effects of submerged culture to a certain extent.The body of rainbow trout in the bubble group was more streamlined than that in the control group,with an increased relative area of fin and tail,which may be an improvement measure for rainbow trout to cope with the lack of buoyancy.In conclusion,the large and medium bubbles are more effective in alleviating the negative buoyage of rainbow trout,probably because the large bubbles are more conducive to being swallowed by the fish and compressed to the swim bladder tube.