THE EFFECT OF BREEDERS DIET IN THE SEAHORSE Hippocampus reidi: ASSESSMENT OF STABLE ISOTOPES AND FATTY ACIDS IN NEWBORN

Diet composition in fish breeders is generally reflected in newborn. This study combines for the first time both stable isotope profiles (δ¹³C and δ¹⁵N) and fatty acids (FA) composition to assess the effect of breeder's diet in newborn juveniles for a whole breeding season (6 months).

Seahorse females are batch spawners with repeated brooding of males within a breeding season. The effect of breeder's diet preceding breeding season on stable isotopes (δ¹³C and δ¹⁵N) and fatty acids inheritance was experimentally assayed in the seahorse Hippocampus reidi. Two homogeneous (size, weight) groups (M0 and M5) of adult seahorses were maintained for 5 months preceding the breeding season. The breeders were fed on unenriched adult Artemia (Diet 0M) or a mixture (1:1) of unenriched adult Artemia and frozen Mysidaceans Neomysis sp. (Diet 5M). Seahorses were fed on the mixed diet for the whole breeding season (6 months). Newborn were analyzed for table isotopes and FA. PCA was applied to selected data (Figure 1).

More batches were produced in treatment 5M. Also, general characteristics, isotopic profiles and FA composition (PUFA) differed among the treatments for the first half of the breeding season. However, juveniles produced on the second half of the season were similar, except for growth and size (5M-L>0M-L). The results achieved demonstrate the long time (>3 months) required for the breeder's diet to take effect on newborn.

Fig 1. PCA results. Treatments: 0M and 5M- Period of male's pouch release: E - Early and L - Late.

This study was financed by project CGL2015-68110-R (Spanish Ministry of Economy, Industry and Competitiveness).