The effect of dietary arachidonic acid during the Artemia feeding period on larval growth and skeletogenesis in Senegalese sole, Solea senegalensis

To improve the understanding of the incidence of skeletal deformities in Senegalese sole (Solea senegalensis), a feeding trial was carried out to evaluate the effect of increasing dietary arachidonic acid (ARA) levels during the Artemia feeding period on larval growth and skeletogenesis. Larvae were fed from 8 to 50 days post hatching (dph) with Artemia nauplii enriched with three different levels of ARA: ARA-Low, ARA-Medium and ARA-High (1.0, 4.5 and 7.0% ARA of total fatty acids, respectively). Increasing levels of dietary ARA did not affect significantly the survival. However, it influenced growth; larvae from the ARA-M group presented the highest values of final standard length and dry weight (11.36 ± 0.47 mm and 5.86 ± 1.06 mg at 50 dph, respectively) and larvae from the ARA-H group the lowest ones (9.53 ± 0.27 mm and 2.47 ± 0.26 mg at 50 dph). The skeleton of larvae fed the ARA-M diet tended to be more calcified at 15 dph than that of larvae fed ARA-L and ARA-H diets. Larvae from the ARA-M group tended to show a higher incidence of fusion of hypurals 3 and 4 (34.4 ± 3.1%) at 50 dph than the larvae from the other groups (18.7 ± 1.6%, in average). The latter results reflected a trend to a higher degree of skeletal development rather than a deformity, this being in agreement with the higher larval growth of this group. Besides, ARA levels did not affect significantly the incidence of total skeletal deformities (41.4 ± 1.5% in average). Larvae from all dietary treatments mostly displayed fusions of the vertebra 43 and 44 (32.2 ± 1.3% in average). The amount of 4.5% of total fatty acid of dietary ARA during Artemia feeding period promoted the best growth and proper skeletogenesis in Senegalese sole larvae.