Algae in Fish Feed: Performances and Fatty Acid Metabolism in Juvenile Atlantic Salmon

Abstract

Algae are at the base of the aquatic food chain, producing the food resources that fish are adapted to consume. Previous studies have proven that the inclusion of small amounts (<10% of the diet) of algae in fish feed (aquafeed) resulted in positive effects in growth performance and feed utilisation efficiency. Marine algae have also been shown to possess functional activities, helping in the mediation of lipid metabolism, and therefore are increasingly studied in human and animal nutrition. The aim of this study was to assess the potentials of two commercially available algae derived products (dry algae meal), Verdemin (derived from Ulva ohnoi) and Rosamin (derived from diatom Entomoneis spp.) for their possible inclusion into diet of Atlantic Salmon (Salmo salar). Fish performances, feed efficiency, lipid metabolism and final product quality were assessed to investigated the potential of the two algae products (in isolation at two inclusion levels, 2.5% and 5%, or in combination), in experimental diets specifically formulated with low fish meal and fish oil content. The results indicate that inclusion of algae product Verdemin and Rosamin at level of 2.5 and 5.0% did not cause any major positive, nor negative, effect in Atlantic Salmon growth and feed efficiency. An increase in the omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) content in whole body of fish fed 5% Rosamin was observed.

Defatted Biomass of the Microalga, Desmodesmus sp., Can Replace Fishmeal in the Feeds for Atlantic salmon

“…On the contrary, Entomoneis spp. (5%) in the diets of Atlantic salmon did not alter the growth or PER, but lowered the FCR (Norambuena et al, 2015). In the present feeding study, we did not observe any difference in either the specific growth rate (1.04-1.07) or protein efficiency ratio (2.32-2.36) of salmon that consumed the defatted meal of Desmodesmus sp.…”

“…In Atlantic salmon, the digestibility of protein and lipid of feeds containing Entomoneis spp. (5%) were 83 and 87, respectively (Norambuena et al, 2015). The protein, lipid and energy digestibility values of an algal product made from Schizochytrium sp.…”

Chlorella vulgaris as Protein Source in the Diets of African Catfish Clarias gariepinus

“…This could be due to the high and amino acid content which are reported well for lowering FCR in bigger fish. Nevertheless, some previous researchers noted that inclusion of algae in diets of carnivorous fish like salmon did not have any effect except on FCR [21]. Others, like Güroy et al [44], noted no visible growth effect in rainbow trout, and in European sea bass (Dicentrarchus labrax), as did Valente et al [13].…”

An overview of the utilisation of microalgae biomass derived from nutrient recycling of wet market wastewater and slaughterhouse wastewater

“…(2%), followed by the growth rate of juvenile Atlantic Salmon feeding on Entomoneis spp. (2.5%) (Norambuena et al 2015).…”

“…Therefore, in-depth research is needed to understand the dietary requirements of fish for the development of diets that can replace fishmeal as the major source of dietary protein for farmed fish Microalgae is seen as a fish feed alternative due to their low production cost, rapid growth rates, abundance in stock, and high nutritional value. It was found that microalgae biomass have successfully been used as fish feed for Tilapia (Oreochromisniloticus) and provided sufficient protein to enhance fish weight (Badwy et al 2008;Vizcaíno et al 2014;Norambuena et al 2015). Roy et al (2011) examined the use of microalgae biomass as fish feed.…”