Inorganic, organic, and encapsulated minerals in vegetable meal based diets for Sparus aurata (Linnaeus, 1758).

David Domínguez,Silvia Torrecillas,Kristin Hamre,Simona Rimoldi,Lidia E Robaina,Marisol Izquierdo,Vasileios Karalazos,María J Zamorano,Genciana Terova

doi:10.7717/peerj.3710

David Domínguez, Silvia Torrecillas + Show 7 more

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https://doi.org/10.7717/peerj.3710

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Abstract

Substituting fishmeal (FM) with vegetable meal (VM) can markedly affect the mineral composition of feeds, and may require additional mineral supplementation. Their bioavailability and optimal supplementation levels depend also on the form of delivery of minerals. The aim of the study was to determine the effect of different delivery forms of three major trace elements (Zn, Mn and Se) in a marine teleost. Gilthead sea bream juveniles of 22.5 g were fed a VM-based diet for 12 weeks that was either not supplemented with these minerals or supplemented with inorganic, organic, or encapsulated inorganic forms of minerals in triplicate and compared to a FM-based diet. Our results showed that mineral delivery form significantly affected the biochemical composition and morphology of posterior vertebrae. Supplementation of VM-based diets with inorganic forms of the target minerals significantly promoted growth, increased the vertebral weight and content of ash and Zn, enhanced bone mineralization and affected the vertebral shape. Conversely, encapsulation of inorganic minerals reduced fish growth and vertebral mineral content, whereas supplementation of organic minerals, enhanced bone osteogenesis by upregulating bone morphogenetic protein 2 (bmp2) gene and produced vertebrae with a larger length in relation to height. Furthermore, organic mineral forms of delivery downregulated the expression of oxidative stress related genes, such as Cu/Zn superoxide dismutase (Cu/Zn sod) and glutathione peroxidase 1 (gpx-1), suggesting thus that dietary minerals supplemented in the organic form could be reasonably considered more effective than the inorganic and encapsulated forms of supply.

Highlights

Gilthead sea bream (Sparus aurata) is one of the main marine finfish produced in the European aquaculture (APROMAR, 2015)
This replacement may decrease antioxidant status (Saera-Vila et al, 2009). These issues may arise even when diets are formulated to satisfy the recommended nutrient requirements for essential fatty acids or amino acids (NRC, 2011). This suggests possible nutritional imbalances, which can be partly related to differences in the content of zinc (Zn), manganese (Mn), and selenium (Se) between FM and Vegetable meals (VM) (NRC, 2011; Hansen & Hemre, 2013), and can affect bone morphology and antioxidant status
From 47 days of feeding until the end of the trial, body weight was significantly lower in fish fed the VM-based diets, containing only 15% FM and 7.5% fish oil (FO), than in fish fed the FM diet (Table 3)

Summary

Introduction

Gilthead sea bream (Sparus aurata) is one of the main marine finfish produced in the European aquaculture (APROMAR, 2015). Vegetable meals (VM) and oils (VO) can partially replace FM and FO in gilthead sea bream diets (Robaina et al, 1995; Montero et al, 2003; Gómez-Requeni et al, 2004; Izquierdo et al, 2005; Benedito-Palos et al, 2007). This replacement may decrease antioxidant status (Saera-Vila et al, 2009). These issues may arise even when diets are formulated to satisfy the recommended nutrient requirements for essential fatty acids or amino acids (NRC, 2011). This suggests possible nutritional imbalances, which can be partly related to differences in the content of zinc (Zn), manganese (Mn), and selenium (Se) between FM and VM (NRC, 2011; Hansen & Hemre, 2013), and can affect bone morphology and antioxidant status

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