Effects Of Dissolved Oxygen Levels, Exercise Training And Fasting On The Locomotion Performance In Juvenile Spinibarbus Sinensis (Dissolved Oxygen Levels In Parabramis Pekinensis)

Firstly, the juvenile Parabramis pekinensis [weight:( 4.70±0.11 g ) , n = 32] and Spinibarbus sinensis [weight:( 3.26±0.06 g) , n = 32] were exposed to acute hypoxia at 25℃.The critical swimming speed (U_crit) and swimming metabolic rate(MO₂)were measured by the swimming metabolic instrument under different dissolved oxygen levels(saturated level 8,4,2,1 mgO₂L^-1),then we calculated the comparative critical swimming speed(U_r),maintenance metabolism(MO₂rest),maximum locomotory metabolism(MO₂active),metabolism scop(MS)and cost of transport(COT)etc correlative parameter. Secondly, we studied the effect of dissolved oxygen levels on critical swimming speed in Juvenile Parabramis pekinensis (4.70±0.11 g) and Spinibarbus sinensi(s3.26±0.06 g), the effect of hypoxia-trained ,exercise training and fasting on the locomotion performance in juvenile Spinibarbus sinensis (9.89±0.12g). Respectivly ,hypoxia- acclimation 48h, exercise- trained 2 weeks( trained 6h daily at 60% U_crit) and fasting 2 weeks for juvenile Spinibarbus sinensis ,then measured their U_crit ,endurance time of swimming at 1.2 U_crit and relative parameters(MO₂rest, MO_2peak,EPOC) of excess post-exercise oxygen consumption. Before exhausted and during the recovey(0,0.5,1,2,4,8,16h), we sampled blood,musle and liver ;then measured the content of dextrose,hepatin and lactic acid . The present study was to examine the effect of those treatments on swimming performance for fish , to provide useful data for protection of local fish species in Three Gorges Reservoir, by comparing the different change of locomotor performance of juvenile Parabramis pekinensis and Spinibarbus sinensis with the varied dissolved oxygen ,different effect on aerobic and anaerobic swimming performance for the two fish ,after hypoxia-trained,exercise-trained and fasting treatment .The results as follows:1.The effect of dissolved oxygen levels in juvenile Parabramis pekinensis and Spinibarbus sinensis 1.1 As the dissolved oxygen levels decreased ,the The critical swimming speed (U_crit) of juvenile Parabramis pekinensis and Spinibarbus sinensis also decreased at the same time .All the groups of both of the fishes have significant difference(P <0.05) while a group of juvenile Spinibarbus sinensis between 4 and 8 mgO₂L^-1 showed no significant change.1.2 There is another founding that the assumption of oxygen (MO₂) lift as the swimming speed rised and decreased with the decline of dissolved oxygen levels; the MO₂rest of both of the fishes appeared the minimum value at 1 mgO₂L^-1. .And the MO₂active and MS of the two kinds of fishes decreased significantly while the decline of different dissolved oxygen levels(P <0.05).2.Effects of low dissolved oxygen levels, exercise training and fasting on the locomotion performance in juvenile spinibarbus sinensis2.1 Compared with control group ,low oxygen levels has no significant difference on U_crit and Stamina. Only exercise training lead to U_crit increased significantly((P<0.05),and the fasting group not only U_crit significantly reduced, Stamina also rise significantly (P < 0.05).2.2 Three kinds of treatment all lead to MO₂rest decreased significantly, and the fasting group decreased the greatest (P< 0.05). The MO_2peak of low oxygen level group had no significant change while the exercise training and fasting group changed significantly (P< 0.05) but there is no significant difference between both groups Three kinds of conduct have no significant impact on EPOC of experimental fish .2.3 In the process of recovery after exhaustive exercise and before the exercise, There were no significant changes in blood-sugar in the four groups of experimental fish. Compared with the control group, the exercise training and hunger induce blood-sugar decrease in the experimental fish; exhaustive exercise induce the lactate levels of the four groups fish increased remarkably. The recovery of the blood lactate in hypoxemia acclimated group cost 0.5h, though the other three groups need 2h. The blood lactate levels was higher in the exercise training group both before and after the exhaustive exercise compared with other groups, the exercise training group were placed in the middle, and the fasting group always at the lowest leaves;2.4 After exhaustive exercise, the glycogen levels in muscle were reduced in the four groups, the control group and hypoxemia acclimated group never recovered, exercise training group recovered after 8h, the fasting group present tend increased initiate and decreased later; compared with the control group, the muscle glycogen were remarkable decreased in the other groups(P<0.05);the muscle lactates in the experimental fish were expressed trend increase initiate and decrease later, while only the exercise training group changed remarkable(P<0.05);compared with control group, the muscle lactates was lower in the fasting group, and other groups no significant changed.2.5 Glycogen and lactic acid in liver of four groups experimental fish have no significant influence before or after exhaustive exercise .The indications as follows:1. To deal with the sudden change of the environment of dissolved oxygen ,the swimming ability have significant difference between the two fish: juvenile Spinibarbus sinensis swims faster ,2. Besides, without 1 mgO₂L^-1 juvenile Spinibarbus sinensis also performs higher swimming efficiency .3. Low oxygen level has no effects on the aerobic and anaerobic exercise ability of juvenile Spinibarbus sinensis .4. Exercise training can improve aerobic exercise ability of Experimental fish,but have no significant influence on anaerobic exercise ability.5. Fasting could cause the ucrit related to aerobic ability of juvenile Spinibarbus sinensis and MO₂,MO_2peak related to anaerobic ability decreased significantly while Stamina improved obviously ,EPOC keep steady.6. According to compared with hypoxia, exercise training and fasting on the locomotion performance in juvenile Spinibarbus sinensis and found that different treatments on the juvenile fish showed different influence on the swimming speed ,among all of the treatments fasting showed the greatest influence.