Figure 1.
Swim-training increased burst frequency and growth in trained fish.
A) Average number of bursts per second ± standard deviation as a function of age in days post fertilization (dpf). B) Average standard lengths (dots) ± standard deviation (with quadratic regression fit) as a function of age (dpf).
Figure 2.
Swim-training accelerated both chondrogenesis and osteogenesis.
A) CF50age values of trained fish plotted against CF50age values of control fish with a linear regression fit (solid line). Dashed line is a reference line which indicates the CF50age values which are not different between control and trained fish. Plus signs indicate cartilage structures without BF50age values, squares are with BF50age values. B) Similar plot as in A but with CF50lgt values. C) Duration of cartilage phase for cartilage bones (in days, indicated with squares in A and E) plotted against the CF50age values of control and trained fish with a linear regression fit (solid lines) (trained fish: black dots and black regression line, control fish: grey dots with grey regression line). D) Similar plot as in C but with duration of cartilage phase (days) plotted against the CF50lgt values of control and trained fish. E) Similar plot as in A but with BF50age values. Red dots indicates BF50age values of dermal bones, plus signs of cartilage bones without CF50age values, squares of cartilage bones with CF50age values. Dashed line see A. F) Similar plot as in E but with BF50lgt values.
Figure 3.
Swim-training had a differential effect on the age at appearance of cartilage structures between control and trained fish.
A,B) CF50age values visualized in the corresponding structures in control fish (A) and trained fish (B). C) Differences in CF50age values between control and trained fish. Positive values indicate that structures appear earlier in the trained fish. Structures with a difference less than twice the standard error are indicated in grey.
Figure 4.
Swim-training had a differential effect on the order of appearance of cartilage and bone structures between control and trained fish.
A,B) Difference in the rank of cartilage (A) and bone (B) structures between control and trained fish. Red structures indicate a forward shift in the order of appearance, blue structures a delay. Structures which did not show a difference are indicated in grey.
Figure 5.
Swim-training had a differential effect on on the age at appearance of bone structures between control and trained fish.
A,B) BF50age values visualized in the corresponding structures in control fish (A) and trained fish (B). The branchial region is indicated separately, ventral view. C) Differences in BF50age values between control and trained fish. Positive values indicate that structures appear earlier in the trained fish. Structures with a difference less than twice the standard error are indicated in grey.
Figure 6.
Schematic representation of the swim-training set-up in lateral view and critical flow velocity.
A) Water was pumped (1) to the top aquarium and flowed back into the reservoir via the training tubes (4), outflow tubes (5) and outflow hoses (6) due to gravity. The difference in water level between the top aquarium and the outflow tubes (5) (indicated with up down black arrow) determined the flow velocity in the training tubes (4). Control fish were kept in similar tubes in the same set-up (7). Both the training and control section consisted of five tubes placed parallel to each other (not visible in drawing). Each tube had its own outflow tube and hose. B) Critical flow velocity (Ucrit) over time and during swim-training experiments (Ucritse). Zebrafish were subjected to 50% (Ucrit50%) of the moving average Ucrit (Ucritma).
Table 1.
Number of fish sampled during each stage in a swim-experiment.