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ABSTRACT. Aquafeeds are formulated with a high content of fishmeal as protein source. The fishmeal is usually produced from pelagic fish resulting in a reduction of fish availability for human consumption. Thus, it is important to find appropriate protein substitutes in the production of formulated aquafeeds. Several works reported the positive effect of partial addition of poultry by-product meal (PBM) in aquafeeds for different fish species, and from them it is clear that the total substitution of fishmeal is limited by the unbalance of essential fatty acids. In this work, aquafeeds were designed with the total and partial substitution of fishmeal by PBM and enriched with acid fish silage. The designed aquafeeds were evaluated in the rainbow fish Oncorhynchus mykiss growth. Six diets were formulated at different levels of substitution of fishmeal by PBM pet feed grade (33, 66 and 100%), with and without addition of acid fish silage (FS) from tuna fish by-products. All treatments were formulated to contain similar protein and energy in a factorial random design with three repeti tions. The diet containing 100% enriched PBM (EPBM) showed the highest specific growth rate (2.0% day -1 ) (P < 0.001), whereas the lowest growth rate was observed with PBM33 without enrichment (1.76% day -1 ), after 22 weeks treatment These results demonstrate that the addition of FS in an aquafeed containing only poultry by-product meal as protein source improves the growth of rainbow fish. The positive effect of FS, mainly the role of essential fatty acids, is discussed. Keywords: Oncorhynchus mykiss, poultry by-products meal, trout, aquafeeds, protein.Substitución total y parcial de harina de pescado por subproductos avícolas (grado mascota) sólo y enriquecido con ensilaje ácido de pescado, en alimentos acuícolas para juveniles de trucha arcoíris Oncorhynchus mykiss RESUMEN. Los alimentos acuícolas son formuladas con alto contenido de harina de pescado que es producida con peces pelágicos (FN por sus siglas en inglés), disminuyendo la posibilidad que sean destinados a consumo humano, lo que motiva la necesidad de encontrar sustitutos proteínicos para formular estos alimentos. Se conoce el efecto positivo de los subproductos avícolas (PBM por sus siglas en inglés) en alimentos acuícolas, aun sin encontrar la substitución total de la FM por un balance inadecuado de ácidos grasos. En este trabajo las dietas se diseñaron con una substitución total y parcial de la harina de pescado por PBM sólo y enriquecido con ensilado ácido de pescado (FS por sus siglas en inglés). Las dietas fueron evaluadas en trucha arcoíris Oncorhynchus mykiss. Seis dietas se formularon con diferentes niveles de sustitución de FM; tres PBM (33, 66 y 100%), y otras tres dietas en niveles similares, pero con PBM previamente enriquecida (EPBM) con FS utilizando subproductos de atún en una proporción de 60(PBM):40(FM) (peso: volumen). Todos los tratamientos __________________ Corresponding editor: Patricio Dantagnan 328 Latin American Journal of Aquatic Research trata...

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The effect of a formulated diet (FD), a seaweed diet (SW), and a mixture of both (FD + SW) on growth, survival rate, and fatty acid content in the tissue of juvenile Haliotis fulgens abalone grown under commercial culture conditions, was analyzed over a 329-day period. Survival and growth rate in terms of length and weight were different with each of the diets evaluated, being significantly higher (P < 0.05) with the mixed diet (FD + SW), followed by SW and FD. Since feed intake was not evaluated in this preliminary study, differences in growth cannot be attributed to the dietary treatments; however, the importance of this work was to show the significant impact of the diet treatments on the tissue fatty acid profiles, suggesting that the treatments contribute to the composition of some fatty acids found in muscle. The polyunsaturated fatty acid (PUFA) 22:4n-6 was not detected in any of the diets, while 20:4n-3 was only present in SW and 22:5n-3 only in FD. However, after the feeding experiment all these PUFAs were present in abalone tissue. The possible synthesis of PUFAs from dietary n-3 and n-6 fatty acids of shorter hydrocarbon chain is discussed.