Proteogenomic Study of the Effect of an Improved Mixed Diet of Live Preys on the Aquaculture of Octopus vulgaris Paralarvae

Inmaculada Varó,Inmaculada Varó,Ricardo Tur,Camino Gestal,Pedro Domingues,Pablo García-Fernández,Sonia Dios,Amalia E Morales,María Prado-Álvarez,Ignacio Ortea

doi:10.3389/fmars.2021.817701

Abstract

The common octopus is the most demanded cephalopod species for human consumption. Despite important advances realized recently, the main bottleneck for commercial production of the common octopus, Octopus vulgaris, is the mass mortality of paralarvae in the first 15–20 days post-hatching (dph), with the main responsible factors still unknown. Thus, the identification of the limiting culture factors is, therefore, crucial for their aquaculture. This study investigates proteomic and transcriptomic responses of octopus paralarvae fed on an improved live preys-mixed diet (M) compared to an Artemia-based (A) reference diet. M diet resulted in the highest paralarvae specific growth rate obtained to date under culture conditions. This is supported by most of the proteins and genes over-expressed in the M group being linked to the cell cycle and replication, production of structural components, and development of the nervous system. Furthermore, the differential nutritional regulation of several genes and proteins seems to indicate that, instead of fatty acids, the preferred fuels for cephalopods would be proteins and carbohydrates. Also, M diet provides a better nutrient balance, which has allowed carrying out this comparative study in paralarvae under optimal conditions at a more advanced stage of growth (20 dph) than in previous studies. Moreover, the paralarvae culture extended up to 40 dph showed for the first time a proper pre-settlement behavior.

Highlights

The common octopus (Octopus vulgaris) is, nowadays, the most demanded cephalopod species for human consumption
The values for dry weight and specific growth rate (SGR) of paralarvae of 20 dph fed on A diet were 1.2 ± 0.2 mg of dry weight and SGR of 7.1%, whereas the group fed on mixed diet used in the present study (M diet) reached 2.7 ± 0.3 mg and 11.1% SGR
An average of 47% of all unigenes were annotated against the Nt database, 35% of unigenes mapped against sequences deposited in the Nr database, 33% were annotated against protein structure domain and families collection (Pfam) and Gene Ontology (GO) databases, whereas 28% had homology to manually deposited protein sequences in Swiss-Prot

Summary

Introduction

The common octopus (Octopus vulgaris) is, nowadays, the most demanded cephalopod species for human consumption. The real causes of these massive mortalities remain still unknown, and various factors related with the zootechnical production (i.e., temperature, water quality, and photoperiod, or light condition) have been referred as possible sources of stress that can negatively affect the viability of the octopus paralarvae rearing (Iglesias and Fuentes, 2014; Garrido et al, 2018). The supply of different species of decapod crustacean zoeae (i.e., Maja brachydactyla, Pagurus sp, and Grapsus adscensionis) and amphipods in co-feeding with Artemia, and the use of Artemia metanauplii enriched with marine lecithin (LC60, rich in phospholipids and long-chain polyunsaturated fatty acids (LCPUFAs) have notably improved paralarvae culture performance (Iglesias and Fuentes, 2014; Reis et al, 2015, 2021; Garrido et al, 2016, 2018). The use of these diets did not produce the rearing outputs needed for the scale-up and establishment of industrial production

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