Triplicate groups of rainbow trout (Oncorhynchus mykiss) (1.4 ± 0.1 g) were fed experimental diets containing four levels of protein substitution to totally replace fishmeal with poultry by‐product meal (0, 33, 67 and 100%). Fishmeal (FM) from tuna fish by‐products and poultry by‐product meal ‘pet food grade' (PBM) were used. Diets were formulated to be isonitrogenous (43.5% crude protein) and isolipidic (12.5% crude fat). After 80 days of feeding, no significant differences were found in terms of thermal unit growth coefficient (TGC). However, the EPA levels in muscle tissue among treatments 0PBM, 24PBM and 44PBM were found to be significantly higher than those for the 59PBM diet. Nevertheless, a re‐feeding period with the control diet showed that 28 days was long enough to regain the FA profile needed. We concluded that PBM used up to 44% in diets for juvenile rainbow trout can be used without a significantly decrease in EPA and DHA under the present conditions. The use of a whole fishmeal diet could be an important strategy to recuperate the fatty acid profile obtained when trout is feed on PBM basis. It will be important to perform longer experiments with larger fish to confirm these results.

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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Two trials were carried out in the laboratory in order to assess the effect of microparticulated feed (F) and live (Thalassiosira pseudonana, M) diets on the growth of recently set (396 ± 13 lm shell height) and 2 mm Crassostrea gigas postlarvae. Different proportions of M and F (100:0, 75:25, 50:50; 25:75, 0:100) were delivered in a single dose of 3 h d -1 in trial 1. Dietary M:F proportions of 100:0, 50:50, and 0:100 were delivered as a single pulse of 8 h d -1 (P1) or two pulses of 4 h -1 (P2) in trial 2. Maximal daily M ration was 296 cells ll -1 d -1 (trial 1), 150 M cells ll -1 d -1 (trial 2), or their equivalent F dry weight. Shell height (SH), dry (DW), and organic weight (AFDW) were evaluated weekly. Oysters from trial 1 significantly increased their size after 28 days, and exhibited no significant dietary differences in terms of DW (1.21 ± 0.15 to 2.01 ± 0.28 mg) or AFDW (0.091 ± 0.022 to 0.166 ± 0.029 mg). Newly set postlarvae (trial 2) also exhibited significant growth after 25 days. No dietary differences were observed in trial 2, yet P2 oysters attained significantly higher shell heights (825-912 lm) than P1 oysters (730-766 lm) after 25 d. Pulse effects were marginally not significant in terms of AFDW and growth rate. Together, these findings showed that balanced microfeeds have a practical potential for the culture of early C. gigas postlarvae, when they are delivered in pulsefeeding schemes

This work presents the embryonic, larval, and postlarval development of Lithopoma undosa (L. undosa) (20 ± 2 C and the effect of natural inducers on the larval metamorphosis. Embryonic development until hatching of the trochophore larva took 15 h. Early veliger larvae with well‐developed shell were after 24 h. At 48 h, the operculum was completely formed. Cephalic tentacles were visible after 72 h. Larvae reached competence 6 to 7 d after fertilization, and was characterized by the presence of branched cephalic tentacles. The effect of natural inducers was evaluated. The percentage of metamorphosis with diatoms and adult mucus was 94% and 58% respectively, differing from the 25% without inducer. When was repeated, the metamorphosis was 100%, and 16% with benthic diatoms. The initial mean size of the postlarvae was 0.316 ± 0.02 mm. After 264 d the juveniles had attained a mean size of 5.98 ± 0.16 mm. These results will not only be of use in the evaluation of the culture of L. undosa, but also in studies on the characterization of inducers.