Physiological effects of natural olive oil antioxidants utilization in rainbow trout (Onchorynchus mykiss) feeding

Abstract

Olive mill vegetation water (VW) is an olive oil by-product rich in polyphenols has powerful antioxidant effects. In light of the interest on the research of novel natural antioxidants to use in fish feed, the aim of this research was to use VW as a potential substitute for artificial antioxidants in rainbow trout diet as well as checking its effects on the blood chemistry and digestive organ physiology of the fish. The experimental plan was monofactorial, balanced (4 9 3) and the experimental factor considered was the fish diet. Diets were isoproteic (CP 40%) and isoenergetic (18 MJ kg -1 DM) with two inclusion levels of VW (1 and 5%: VW1 and VW5) tested against a control diet. A feeding trial was performed on quadruplicate groups of 200 fish (mean body weight: 44.2 g) fed experimental diets for 94 days. At the end of the trial, the growth performance traits were determined and sampling of blood and different tissues (brain, ovary, stomach, liver, and intestine) were carried out for haematology, endocrinology, histology, and digestive enzyme analysis. The main results of the present experimentation are that VW inclusion in rainbow trout feed slightly affects the productive traits and blood chemistry, while the histological structure of digestive organs and digestive enzyme physiology were not affected.

Olive oil by-product as a natural antioxidant in gilthead sea bream (Sparus aurata) nutrition

“…It is also evident that the antioxidant effect of VW inclusion in fish feed increased with increasing VW level. In the study on rainbow trout nutrition with VW inclusion by Sicuro et al (2009), similar results were obtained in the TBARS analysis: there was an improvement in the TBARS analysis in fish consuming VW-supplemented feed inclusion, but the difference was not evident in all of the samples analysed. We also investigated several physiological parameters to determine whether certain polyphenols had negative effects.…”

“…The absence of differences in the production traits between experimental treatments suggests the possibility of utilising VW in sea bream feed. Sicuro et al (2009) reported a number of anti-nutritional effects of VW in a study involving the inclusion of similar levels of VW in rainbow trout feed. Sea bream seems to be more tolerant to high levels of these polyphenols in fish feed, and this could be an advantage for the future of the aqua-feed industry, given the large production of VW in Mediterranean countries, despite the need for a polyphenol purification method.…”

Poultry by-product meal as an alternative to fish meal in the juvenile gilthead seabream (Sparus aurata) diet

“…Hematic cortisol is a parameter commonly used to evaluate fish welfare (Sadler et al, 2000;Campbell, 2004;Haukenes et al, 2008;Sicuro et al, 2009) and provides a good indication of intensity and duration of stress in gilthead seabream (Jentoft et al, 2005;Syriou et al, 2011). Our result clearly suggests that PBM meal based diet did not determine, per se, stress in this fish species.…”

Zebrafish as animal model for aquaculture nutrition research

“…Additionally, the diversification of new protein ingredients (from animals and plants), and identification of additives (natural or synthetic) with “intestinal protective” activity to promote growth and health have been made a priority (Refstie et al, 2010; Sicuro et al, 2010; Czubinski et al, 2014). Thus, the effects of nutrition on genomics and immunity are being addressed (Montero et al, 2010; Hernández et al, 2013).…”