WWW.WAS.ORG • WORLD AQUACULTURE • MARCH 2018 55 Fishmeal continues to be one of the main protein sources used in commercial feeds for trout and salmon, although its availability is not expanding and its cost is increasing (FigueiredoSilva and Lemme 2014). Toward sustainable aquaculture, Naylor et al. (2000) proposes a reduction of fishmeal and fish oil input in feed and promotion of environmentally sound aquaculture practices. Many investigators have replaced partially or totally replaced fishmeal with several animal or plant protein sources for different fish species. Previous experiences carried out at CENADAC with pacú and South American catfish (both omnivorous species) demonstrated that it is possible to totally substitute fishmeal with animal and plant feedstuffs (Wicki and Luchini 2004, Wicki et al. 2008). Feedstuffs of animal origin are generally considered to be of higher quality than those of plant origin, primarily because of their higher protein content and superior essential amino acid profile (Robinson and Li 1998). Also, there have been efforts to increase the proportion of plant ingredients such as soybean meal and corn gluten meal (Moyano et al. 1992, Gomes et al. 1995). This article describes a study where fishmeal was partially substituted with a mix of different feedstuffs used to prepare diets for rainbow trout. This mix contains a similar amino acid profile to that of fishmeal. Study Methods The study was carried out at CENADAC (National Aquaculture Development Centre, Argentina, Fig. 1) between June and October (winter months) and finished when water temperatures Partial Substitution of Fishmeal with a Mix of Animal and Vegetable Feedstuffs for Rainbow Trout in Argentina Gustavo Wicki, Oscar Galli Merino, Facundo Sal, Pablo Candarle, Luis Romano and Rolando Hernandez increased and feeding was not possible. Three 1000-L fiberglass tanks were used for each treatment. Twenty-five fish were stocked into each tank (Fig. 2), and water exchange (10 L/min) and supplemental aeration were provided. Three experimental feeds were formulated (Table 1). A control diet contained 100 percent fishmeal, treatment A contained 50 percent fishmeal and 50 percent of an ingredient mix; treatment B contained 25 percent fishmeal and 75 percent of the ingredient mix. The ingredient mix was made by Asociación de Cooperativas Argentinas and consisted of blood meal (15 percent), high-protein soybean meal (10 percent), poultry byproduct meal (20 percent), corn gluten meal (12 percent), brewers yeast (33 percent) and egg albumin (CONTINUED ON PAGE 56) FIGURE 1. Fiberglass tanks at the National Aquaculture Development Centre, Argentina. FIGURE 2. Rainbow trout at stocking were 40-50 g. TABLE 1. Feed rations tested during feeding trial. Ingredients Control (%) Treatment A (%) Treatment B (%) Fish Meal 30 15 7.5 Mix Ingredients 15 22.5 Sunflower meal 33 33 33 Meat meal 15 15 15 Corn 11 11 11 Wheat Meal 5 5 5 Fish oil 5 5 5 Mineral & vitamin 1 1 1
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