Potential of Thraustochytrids to Partially Replace Fish Oil in Atlantic Salmon Feeds

Abstract

The replacement of fish oil with a dried product made from thraustochytrid culture, a marine microorganism, in canola-oil-based diets for Atlantic salmon was investigated. Salmon (37 g) were fed for 51 days on diets containing only canola oil, canola oil and fish oil, or canola oil and the thraustochytrid. There were no significant differences in final weight (106.1 +/- 1.1 g), weight gain (69.6 +/- 1.1 g), feed consumption (16.5 +/- 0.2 mg dry matter g(-1) d(-1)), feed efficiency ratio (1.15 +/- 0.03 g (g-1)), or productive protein value (51.2% +/- 1.7%) between the diets. Nor were there any significant differences in whole-body chemical composition, organ somatic indices, or measures of immune function. However, following transfer to seawater and 2 challenges with Vibrio anguillarum, cumulative mortality was significantly lower in fish fed some fish oil than in those fed the 2 diets containing no fish oil. In conclusion, the thraustochytrid had no detrimental effects on the performance of salmon but, at the current inclusion of 10%, failed to confer the same effect as fish oil under challenging conditions.

Feeding aquaculture in an era of finite resources

“…The whole-cell biomass or algal meal after extraction of these microorganisms is now used to feed larval stages of marine finfish, such as striped trumpeter, and is fed to chickens to enrich the eggs. One group of microorganisms (thraustochytrids) has also been successfully used in trials for use in the grow-out phase of Atlantic salmon, either as whole-cell biomass or the extracted SCO (37,38). In those studies, fish oil was completely replaced by thraustochytrid oil in Atlantic salmon parr diets, resulting in comparable growth and fish health while increasing the concentration of DHA in fish flesh.…”

Regiospecificity profiles of storage and membrane lipids from the gill and muscle tissue of atlantic salmon (Salmo salar L.) grown at elevated temperature

“…The water temperature of 19°C was considerably above the optimum although representative of environ- Table 1. mental conditions now experienced by an established industry in Tasmania, Australia (23). As often observed, the FA profile of fish, particularly the storage (TAG) fraction, is strongly influenced by diet (31,32).…”

“…The tailoring of membrane lipid composition is probably the most ubiquitous and continuously graded cellular response to temperature change (13). Most studies have investigated Atlantic salmon lipids within a temperature range of 2-12°C (19)(20)(21)(22), but none have measured salmon at higher temperatures such as 19°C, a temperature that is now commonly encountered by farmed salmon in Tasmanian waters and that approaches their upper threshold for survival (23). This is the first detailed examination, including regiospecific profiling, of the membrane and storage lipids of salmon from a feeding experiment performed at an elevated temperature of 19°C.…”

Effects of dietary fish oil replacement by microalgae raw materials on growth performance, body composition and fatty acid profile of juvenile olive flounder,Paralichthys olivaceus

“…Many studies have focused on LC-PUFA production from single-cell microalgae (Barclay et al 1994;Pulz & Gross 2004;Spolaore et al 2006;Ganuza & Izquierdo 2007). Research has also suggested single-cell microalgae as promising candidate sources of LC-PUFAs to substitute FO (Harel et al 2002;Carter et al 2003). On the one hand, several microalgae highly rich in LC-PUFA, for example Schizochytrium sp., Crypthecodinium cohnii and Chlorella sp., have been commercially available and produced in a sustainable way.…”