Effects of complete replacement of fish oil with plant oil mixtures and algal meal on growth performance and fatty acid composition in juvenile yellowtail Seriola quinqueradiata

Abstract

Docosahexaenoic acid (DHA) is an essential fatty acid for marine carnivorous fish. Algal meal (AM), available as a new dietary DHA source, could completely replace dietary fish oil (FO). In this study, dietary FO was replaced with plant oil mixtures and AM in juvenile yellowtail Seriola quinqueradiata to investigate its effects on growth performance and fatty acid composition. The FO control diet was prepared with only pollack liver oil as the lipid source. For the non-FO diets, pollack liver oil was completely replaced with mixtures of canola oil and palm oil, with AM supplementation at 0% (AM0), 1% (AM1), 2% (AM2), 3% (AM3), and 4% (AM4). After completion of the 8-week feeding trial, the AM2 group showed significantly higher values for final body weight and feed efficiency than the AM0 group. No significant differences were observed in the other parameters of growth performance. Whole-body fatty acid composition reflected the dietary fatty acid composition in all dietary groups. These findings demonstrate that AM is useful as a DHA source in yellowtail aquaculture, thus contributing to a reduction in the use of FO in fish diets.

Effects of dietary replacement of fish oil with soybean oil on the growth performance, plasma components, fatty acid composition and lipid metabolism of groupers Epinephelus coioides

“…However, this effect was not observed in the present study. An increase in the liver TG level was observed in a previous study on yellowtails fed VO diets, compared with those fed an FO diet (Fukada et al, 2020), which is supported by our results. The adipogenic effect of LA on mice as a result of ARA increase can be prevented by consuming sufficient DHA and EPA (Alvheim et al, 2012), while the lipid-lowering effect of FO is dominated by EPA in rats (Froyland et al, 1996).…”

“…Furthermore, the plasma components (GLU, TG, TC and LDL-C) determined remained unaffected by the dietary SO inclusion levels, which was consistent with the results of a study in yellowtails (Fukada et al, 2020). Plasma biochemical components, as the intermediary products of some metabolic processes, are closely related to the nutritional status of fish across a feeding period (Ye et al, 2011).…”

“…A similar effect was observed in Atlantic salmon fed a diet in which FO was replaced by rapeseed oil (Bell et al, 2001). This could explain why the high SO substitution level caused a high liver deposit in this study and in studies on other farmed fish (Fukada et al, 2020;Gou et al, 2020;. Therefore, the liver lipid metabolism of groupers was in a relatively balanced state irrespective of the dietary SO inclusion level.…”

“…Therefore, the liver lipid metabolism of groupers was in a relatively balanced state irrespective of the dietary SO inclusion level. These results indicate moderate alterations in lipid homeostasis when FO is replaced by SO or other VOs at relatively high levels, without adverse effects on the growth performance (Babalola & Apata, 2012;Deng et al, 2014;Fukada et al, 2020;Sanchez-Moya et al, 2020), thereby supporting the dietary use of VOs for the sustainable production of important farmed marine fish species, such as the grouper.…”

A short pulse of dietary algae boosts immune response and modulates fatty acid composition in juvenileOreochromis niloticus

“…Tilapia is known to be capable of transforming linolenic acid into EPA and DHA, as well as linoleic acid to ARA by increasing desaturation and elongation of C18 fatty acids (Karapanagiotidis, Bell, Little, & Yakupitiyage, 2007; Olsen, Henderson, & McAndrew, 1990; Tocher et al., 2002), and may efficiently preserve ARA, EPA and DHA in the tissues when they are not provided in excess by the diet (Tocher, 2003). Within a 30‐day period, our results are in agreement with previous research showing an increase in n‐3 and n‐6 PUFA after fish were fed with algae diets (Fukada, Kitagima, Shinagawa, Morino, & Masumoto, 2020; Perez‐Velazquez et al., 2018; Stoneham et al., 2018).…”