Diet influence on egg production of the copepod Acartia tonsa (Dana, 1896)

Priscila F Teixeira,José G.F Bersano,Sonia M Kaminski,Alessandro P Cardozo,Tatiana R Avila,Adalto Bianchini

doi:10.1590/s0001-37652010000200009

Priscila F Teixeira, José G.F Bersano + Show 4 more

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https://doi.org/10.1590/s0001-37652010000200009

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Abstract

Egg production in the copepod Acartia tonsa was evaluated using different densities of the microalgae Thalassiosira weissflogii, Chaetoceros muelleri and Isochrysis galbana. Male and female were kept under controlled conditions (salinity 30, 20 degrees C, photoperiod 12L:12D), acclimated to the experimental conditions and left over a period of 24 h to allow copulation. Algal densities tested were equivalent in biovolume and corresponded to 0, 2.5, 5, 10, 20, 40 and 60.10(3) cells.mL-1 of T weissflogii. Ten acclimated female were separated, transferred to glass bottles and exposed for further 24 h to the corresponding experimental medium. After this period, the eggs were fixed and counted. Copepod egg production reached a threshold value when T weissflogii, C. muelleri and I. galbana were supplied at 10.10(3), 140.10(3) and 640.10(3) cells.mL-1, respectively. Mean egg production corresponded to 28.0 +/- 0.5, 20.1 +/- 1.0 and 22.0 +/- 3.5 eggs.female-1 .day-1, respectively. Copepods fed T weissflogii showed the highest mean egg production while those fed I. galbana reached a maximum egg production when the algae were supplied at a density two- to fourfold higher, considering the biovolume of T weissflogii and C. muelleri. These differences are explained considering the different sizes of the microalgae used to feed the copepods.

Highlights

Copepods from the genus Acartia play an important role in the food webs of estuaries in both tropical and subtropical areas (Björnberg 1981, Mauchline 1998)
For the three microalgae species used, mean egg production rate was dependent on the density of food supplied to copepods (Fig. 1)
Mean egg production in copepods fed on T. weissflogii, C. muelleri and I. galbana increased as the algae cell density increased, until reaching 10.103, 140.103 and 640.103 cells.mL−1, respectively

Summary

Introduction

Copepods from the genus Acartia play an important role in the food webs of estuaries in both tropical and subtropical areas (Björnberg 1981, Mauchline 1998) They show the higher biomass values in most shallow enclosed bays and estuaries (Azaiteiro et al 2005, Leandro et al 2007). This fact may be related to their omnivorous feeding behavior, being able to survive and reproduce under different diets (Kleppel 1992, Saiz et al.2007). The high nutritional value of copepods, which is characterized by a rich content in phospholipids, highly unsaturated fatty acids (HUFA), and natural antioxidants (Watanabe et al 1983, Kraul et al 1992, Sargent et al 1997, Støttrup and Nosker 1997, Støttrup 2000, Helland et al 2003), can explain their actual broad use in aquaculture

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