Monola oil versus canola oil as a fish oil replacer in rainbow trout feeds: Effects on growth, fatty acid metabolism and final eating quality

Abstract

Monola oil, a high oleic acid canola cultivar, and canola oil were evaluated as replacers of fish oil at three levels of inclusion (60%, 75% and 90%) in rainbow trout diets. After a 27-week grow-out cycle, the diet-induced effects on growth, fatty acid metabolism and final eating quality were assessed. Overall, no effects were noted for growth, feed utilisation or fish biometry, and the fatty acid composition of fish fillets mirrored that of the diets. Dietary treatments affected fillet lipid oxidation (free malondialdehyde), pigmentation and flavour volatile compounds, but only minor effects on sensorial attributes were detected. Ultimately, both oils were demonstrated to possess, to differing extents, suitable qualities to adequately replace fish oil from the perspective of fish performance and final product quality. However, further research is required to alleviate on-going issues associated with the loss of health promoting attributes (n-3 long chain polyunsaturated fatty acids) of final farmed products.

Acid and re-esterified rapeseed oils as alternative vegetable oils for rainbow trout diets: Effects on lipid digestibility and growth

“…Both total fat and total fatty acid ADC of the different experimental diets were high (90.5-96.7%), which is in accordance with authors reporting similar results with diets including rapeseed as a FO replacer in rainbow trout (Caballero et al, 2002;Martins et al, 2006;Turchini et al, 2013). This replacement could even increase lipid digestibility at low water temperatures in salmonid species (Caballero et al, 2002;Karalazos et al, 2007).…”

“…Final weights of fish fed the experimental single rapeseed oil diets were all high, which is in agreement with many studies in salmonids (Bell et al, 2003;Huang et al, 2008;Pettersson et al, 2009;Turchini et al, 2013). Also, values of FCR and SGR were similar to those obtained in studies including different levels of rapeseed oil in salmonid diets (Caballero et al, 2002;Turchini et al, 2013).…”

“…Also, values of FCR and SGR were similar to those obtained in studies including different levels of rapeseed oil in salmonid diets (Caballero et al, 2002;Turchini et al, 2013). As reported for Atlantic salmon, rapeseed oil is an effective substitute of FO in terms of growth rates and feed efficiency, since it provides sufficient energy in the form of monoenoic fatty acids to maintain high growth rates Bell et al (2001).…”

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“…It is known that number of goblet cells in many species increases toward the rectum and this may be explained by further need for lubrication in this region (Murray et al, 1996;Khojasteh, Sheikhzadeh, Mohammadnejad, & Azami, 2009). It has been reported that CO as a fish oil alternative has no adverse effects on growth, feed utilization, biometry and FA composition in rainbow trout (Turchini et al, 2013). Finally, it has been suggested that total replacement of fish oil by vegetable oils does not induce adverse changes in fish growth and performance (Benitez-Dorta et al, 2013).…”

Impact of Diets Containing Plant Raw Materials as Fish Meal and Fish Oil Replacement on Rainbow Trout (Oncorhynchus mykiss), Gilthead Sea Bream (Sparus aurata), and Common Carp (Cyprinus carpio) Freshness

“…Besides the obvious effects in fillet fatty acids, also the total volatile compounds and sensory properties, namely, the appearance, odour, flavour, and texture of fillet, can be affected [8][9][10][11][12][13][14]. In particular, in cases of sweet-water fish species, the recorded impacts included reduction of the total amount of aldehydes and alcohols concomitant to fillet n-3 fatty acids reduction, increase of n-6 derived aldehydes, and related sensory-perceived "off-flavour" for plant oil fed fish [9,10,15].…”