Table 1.
European eel (Anguilla anguilla) larvae reared in seven different salinity treatments; at 36 psu (con) and in six further scenarios, where salinity was reduced on 0 or 3 days post hatch and at rates of 1, 2 or 4 psu/day (01, 02, 04, 31, 32 and 34) towards iso-osmotic conditions.
Fig 1.
Visualization of European eel (Anguilla anguilla) larval deformities.
Normal (A), spinal curvature (B), emaciation (C), and pericardial edema (D).
Table 2.
Sequences of European eel, Anguilla anguilla primers used for amplification of genes by qRT-PCR.
Primers were designed based on sequences available on Genbank databases. The table lists accession number and corresponding database of target gene sequences.
Fig 2.
Effect of salinity on European eel (Anguilla anguilla) larval mortality and biometry.
Mortality (A), body area (B), growth (C), oil drop utilization (D) and growth efficiency (E) from 2 to 12 days post hatch (dph) as well as occurrence of larval deformities such as spinal curvature (F), emaciation (G) and pericardial edema (H) on 12 dph. Values represent means (± SEM) among three crosses at each age and treatment. Different lower case letters represent significant statistical differences (p < 0.05).
Fig 3.
Effect of age and salinity treatment on European eel (Anguilla anguilla) larval relative expression of selected genes.
No significant salinity × age interaction was detected for any gene. As such, over the entire experimental period, the main effects of age and salinity are displayed for genes encoding Na+K+2Cl- cotransporters (A-F), aquaporins (G-L), and heat shock proteins (M-P). Values represent means (± SEM) among three crosses at each age and treatment. Different lower case letters represent significant statistical differences (p < 0.05).
Fig 4.
Effect of age and salinity treatment on European eel (Anguilla anguilla) larval relative expression of selected genes.
For thyroid hormone receptor αA (thrαA), a significant salinity × age interaction was detected, thus the model was decomposed into a series of reduced ANOVA models to determine the effect of salinity for each age (A). No significant salinity × age interactions were detected for all other genes. As such, over the entire experimental period, the main effects of age and salinity are displayed for genes relating to thyroid hormone receptors (B-E), deiodinases (F-K), and energy metabolism (L-O). Values represent means (± SEM) among three crosses at each age and treatment. Different lower case letters and asterisks represent significant statistical differences (p < 0.05).