Nature more than nurture affects the growth rate of mussels

D Prieto,E Navarro,D Tamayo,I Urrutxurtu,M B Urrutia,I Ibarrola

doi:10.1038/s41598-020-60312-y

Abstract

We tested the hypothesis that environmental trophic conditions prominent during the growing period (nurture conditions) can modify the differing physiological profiles between fast (F)- and slow (S)-growing juveniles of the mussel Mytilus galloprovincialis. Approximately 200 individuals were fed a high organic content diet dosed below the pseudofaeces threshold (BP), whereas another 200 were fed a low organic content diet dosed above the pseudofaeces threshold (AP), forcing them to maintain a continuous production of pseudofaeces. After 3 months, F and S individuals in each rearing condition were selected and used in feeding experiments. We measured the physiological parameters of the energy balance of selected F and S mussels fed on 4 different diets and tested the effects of the rearing condition (BP vs AP) and growth condition (F vs S) upon the physiological variables. Irrespective of the rearing condition, F-mussels attained higher values of scope for growth with the four experimental diets due to their capacity to display higher clearance rates and preingestive selection efficiencies. F-individuals also had higher gill-surface areas than S individuals. We discussed the role of the gills in determining inter-individual growth rate differences in the mussel.

Highlights

We tested the hypothesis that environmental trophic conditions prominent during the growing period can modify the differing physiological profiles between fast (F)- and slow (S)growing juveniles of the mussel Mytilus galloprovincialis
We describe the results obtained in a series of experiments that were performed simultaneously with those in Prieto et al.[8], where two groups of mussel spats were reared and left to size-differentiate under conditions of continuous supply of food: one group was fed a low organic content food at a particle concentration above the pseudofaeces threshold (AP), and the other group was fed a high organic content food at a particle concentration below the pseudofaeces production threshold (BP)
The growth rates (GR: mm/day) of the mussels reared with both diets, below (BP) and above (AP) pseudofaeces threshold, were estimated by adjusting linear regression models to the variations of the mean values of shell lengths with time

Summary

Introduction

We tested the hypothesis that environmental trophic conditions prominent during the growing period (nurture conditions) can modify the differing physiological profiles between fast (F)- and slow (S)growing juveniles of the mussel Mytilus galloprovincialis. In an attempt to untangle the complex physiological basis underlying inter-individual differences in the growth rate of bivalves, Tamayo et al.[7] tested the hypothesis that the environmental conditions prevailing during the growing period (nurture), nutritional conditions such as food abundance, could modify the physiological profiles differing between fast and slow growing juveniles of the www.nature.com/scientificreports mussel M. galloprovincialis. They showed that with a continuous food supply, mussels that grew at higher rates (fast growers: F) differed from slow growers (S) in their innate capacity to display higher feeding rates, whereas in mussels reared under restrictive feeding conditions, the advantageous innate feature in fast growers (F) was their capacity to reduce standard metabolic rates during starvation periods. The other phenotype, referred to as energy savers, is represented by specimens genetically capable of displaying reduced standard metabolic rates and that were found to be faster growing individuals under severe food-restrictive conditions

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