Post-Prandial Amino Acid Changes in Gilthead Sea Bream.

Ioannis Nengas,Eleni Mente,Nikolaos Vlahos,Robin S (Katersky) Barnes,Chris G Carter

doi:10.3390/ani11071889

Abstract

Simple SummaryUsing combinations of plant protein concentrates and EAA supplementation, high levels of replacement (50–75% of fishmeal protein) have been achieved in gilthead sea bream without affecting the growth performance or quality traits. It was confirmed in this study that 16% replacement of marine protein with plant protein meets the amino acid needs of sea bream. The results of the present study suggest the need to further investigate tissue-specific and species-specific responses in the timing and ability to regulate metabolism due to dietary nutrient utilization.Following a meal, a series of physiological changes occurs in fish as they digest, absorb and assimilate ingested nutrients. This study aims to assess post-prandial free amino acid (FAA) activity in gilthead sea bream consuming a partial marine protein (fishmeal) replacement. Sea bream were fed diets where 16 and 27% of the fishmeal protein was replaced by plant protein. The essential amino acid (EAA) composition of the white muscle, liver and gut of sea bream was strongly correlated with the EAA composition of the 16% protein replacement diet compared to the 27% protein replacement diet. The mean FAA concentration in the white muscle and liver changed at 4 to 8 h after a meal and was not different to pre-feeding (0 h) and at 24 h after feeding. It was confirmed in this study that 16% replacement of marine protein with plant protein meets the amino acid needs of sea bream. Overall, the present study contributes towards understanding post-prandial amino acid profiles during uptake, tissue assimilation and immediate metabolic processing of amino acids in sea bream consuming a partial marine protein replacement. This study suggests the need to further investigate the magnitude of the post-prandial tissue-specific amino acid activity in relation to species-specific abilities to regulate metabolism due to dietary nutrient utilization.

Highlights

Fish growth optimization needs an adequate supply of dietary protein for protein deposition [1,2]
The essential amino acid composition of the organic diet was more correlated with the laboratory diet (r2 = 0.97, p < 0.05) than the conventional diet (r2 = 0.95, p < 0.05)
The postprandial increase 4 h after a meal in the total white muscle essential amino acid (EAA) pool in fish (Table 2) suggested that most of the muscle amino acids were utilized at a lower rate

Summary

Introduction

Fish growth optimization needs an adequate supply of dietary protein for protein deposition [1,2]. A low or imbalanced amino acid supply tends to initially stimulate protein synthesis in the liver in order to maintain protein synthesis and growth in the skeletal muscle [2,5]. Dietary amino acid imbalances will lead to increased AA oxidation, increased rates of protein synthesis and turnover and decreased protein retention efficiencies [6]. Protein turnover reflects dietary protein in relation to how closely it matches quantitative and qualitative amino acid requirements [2,9,10]. Essential and non-essential amino acids appeared synchronously in the plasma in juvenile rainbow trout (Oncorhynchus mykiss) fed a fishmeal diet, while the appearance was less synchronized in fish fed a plant meal diet [15]

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