Partial and total replacement of fishmeal by a blend of animal and plant proteins in diets for Seriola dumerili: effects on nutritive performance

Abstract

[EN] A trial of 154 days of duration was carried out to assess the use of an alternative protein blend (wheat gluten meal, corn gluten meal, krill meal and meat meal) as a substitute for fish meal in diets for juvenile greater amberjack (38 g average initial weight), using four isolipidic (140 g kg-1) and isoenergetic extrude diets (24 MJ kg-1) with the same digestible protein (50%). The control diet was FM100, without fishmeal substitution and in the FM66, FM33 and FM0 diets, the fishmeal was replaced at 33, 66 and 100%, respectively. At the end of the experiment no differences in growth parameters were obtained, but a clear tendency of diminishing final weight and specific growth rate (SGR) was observed when the protein mixture dietary levels increased. Survival was negatively affected due to an undetermined fish disease causing high mortality; fish fed the FM0 diet exhibited the lowest survival (23%). A possible explanation of this mortality could found in a dietary amino acid imbalance and or some anti-nutrients factors contained in animal and vegetable meals. With regard to nutritive parameters, daily feed intake (FI), feed conversion ratio (FCR), and, digestible protein intake (DPI), were similar in all the diets; however, the digestible energy intake (DEI) was lowest in fish fed the FM0 diet. No differences were found in the protein efficiency ratio (PER). In terms of whole body composition, significant differences were found in protein composition and about retention indices, only protein efficiency retention showed significant differences. Regarding the digestibility, the ADC for protein, energy and amino acids were diminishing according the fishmeal substitution. Significant differences were observed in the ratio between diet and whole fish body profile (AA) for all essential amino acids. In summary, it can conclude that the total fishmeal replacement by the alternative protein blend assayed was not feasible for yellowtail feeding, because cause a detriment of digestible EAA and energy, and a high mortality in long term fending. The fishmeal substitution at 66% dietary level obtained good growth and nutrient efficiency and high survival

{ES] Durante 154 días se ensayó la sustitución parcial y total de la harina de pescado por una mezcla de fuentes proteicas alternativas (harina de gluten de trigo, harina de gluten de maíz, harina de krill y harina de carne) en piensos extrusionados para juveniles de Seriola dumerili (peso medio inicial de 38 g). Se usaron cuatro dietas isolipídicas (140 g kg-1), isoenergéticas (24 MJ kg-1) e isoproteicas (50% de proteína digestible), con un nivel de sustitución de la harina de pescado del 0, 33, 66 y 100% (dietas FM100, FM66, FM33 y FM0, respectivamente). Al final de la experiencia, no se encontraron diferencias significativas en los parámetros de crecimiento, aunque el peso final y la tasa de crecimiento instantáneo (TCI), disminuyeron con el nivel de sustitución. La supervivencia final disminuyó significativamente en la dieta FM0, debido probablemente a un balance aminoacídico dietario incorrecto y/o a la presencia de factores antinutricionales. Respecto a los parámetros nutritivos, la tasa de alimentación diaria (TAD), índice de conversión del alimento (ICA) e ingesta de proteína digestible (IPD), fueron semejantes; sin embargo, la dieta FM0 tuvo la menor ingesta de energía digestible (IED). No se observaron diferencias significativas en el coeficiente de eficacia en crecimiento (CEC). A nivel de composición corporal, al final de la experiencia se obtuvieron diferencias significativas en el contenido proteico, y en relación a los índices de retención, sólo el valor productivo de la proteína (VPP) mostró diferencias significativas. Los coeficientes de digestibilidad aparentes para la proteína, energía y aminoácidos tendieron a disminuir al aumentar el nivel de sustitución. Se detectaron diferencias significativas en la razón entre el perfil de aminoácidos en las dietas respecto al perfil corporal, para todos los aminoácidos esenciales. Podemos concluir que la sustitución total de la harina de pescado por los componentes proteicos alternativos utilizados en nuestra experiencia, no fue exitosa debido a un perfil aminoacídico no óptimo, a una menor digestibilidad energética y por causar una elevada mortalidad a largo plazo. Sin embargo, un nivel de sustitución del 66% produjo buenos resultados de crecimiento, nutritivos y de supervivencia