Removal of dietary proteins and oils on salmon performance

Atlantic salmon post-smolts of an average of 940g were fed six diets including two marine-based commercial diets one with partial inclusion of vegetable proteins (VPs) and oils (VOs) (2011/12 EU standards) (MB) and a second with partial inclusion of VPs, land animal-by-product (ABP) proteins and VOs (non-EU standards) (MBABP), a fully vegetable protein (VP) diet; a fully algal and VOs (VO) diet; a fishery-free vegetable-based (VP/VO) diet; and a fishery-free diet with a mix of VPs and ABP proteins and a mix of algal and vegetable oils (MFABP). Growth was assessed at Days 104 and 175, whereas fillet proximate composition, haematology and innate immune responses were assessed upon termination. Overall, MB salmon was the best performing group for the full period in terms of feed intake and overall weight gain. MB and VP salmon exhibited the highest FCRs compared to the other groups, while VP salmon exhibited the highest condition factor (K) and VO salmon the lowestKcompared to the other groups. Fillet proximate composition did not present differences among the six groups. MB salmon demonstrated the highest plasma lysozyme activity compared to the other groups while MFABP, VP and VP/VO salmon demonstrated higher plasma anti-protease activity in contrast to MB salmon. The dietary groups did not present differences in plasma protein, total IgM or natural haemolytic activity while unaltered head kidney macrophage respiratory burst activity was also observed. Overall, diets free from marine proteins or oils and/or both were satisfactorily utilized by salmon without compromising their immune capacity, although longer adaptation periods are required

Effect of polyunsatured aldehyde (A3) as an antiparasitary ingredient of Caligus rogercresseyi in the feed of Atlantic salmon, Salmo salar Efecto del aldehído poli-insaturado (A3) como ingrediente antiparasitario de Caligus rogercresseyi en la alimentación de salmón del atlántico, Salmo salar

Some polyunsaturated aldehydes (PUAs) such as 2-trans, 4-trans decadenial (A3) have a detrimental effect on the development of copepod sharmful to the salmon industrysuch as Caligus rogercresseyi (sea lice). The purpose of this study was to evaluate the potential use of A3 as a salmon feed ingredient in order to reduce reproduction of Caligus rogercresseyi in infested Atlantic salmon (Salmo salar). The toxicity of A3 was assessed histopathologically for 7 days, using intra-peritoneal injections of different doses (0, 0.24, 0.47, 2.37, 11.86, and 23.71 mg kg-1) in brain, intestine, skin, liver, and muscletissues of Salmosalar at the end of each treatment. The effect of A3 on sea lice was evaluated using 250 Atlantic salmon in an open-flow system of seawater (~13°C). The effect of the dosage in the fish diet was evaluated at two levels (9 mg kg-1, 18 mg kg-1) and considering a control (without A3) for 4, 8, and 12 days, once the sea lice had reached maturity. As a complement, the persistent effect of diluted A3 in sea water (0.5 g L-1) was evaluated at 10, 12, and 14°C for 0, 1, 3, 6, 10, and 15 days; and the maximum persistence was found at 10 days at 10°C. The results showed that the dosages over 0.47 mg kg-1 had no toxic effect on Atlantic salmon, but induced a detrimental effect on Caligus rogercresseyi (reduction of 15% of mature females with a dose of 18 mg kg-1), which could be attributed to alterations in the embryonic development of the sea lice. A3 is a potential supplement in the diet of salmon. However, studies ofits mechanism of action should be undertaken prior to its use.Algunos aldehídos poli-insaturados (PUAs) tales como 2-trans, 4-trans decadenal (A3) tienen efecto perjudicial para el desarrollo de copépodos perjudiciales para la industria del salmón, tales como Caligus rogercresseyi (piojo de mar). El objetivo del presente estudio fue evaluar el uso potencial de A3 en alimentación de salmones, de forma de reducir la reproducción de Caligus rogercresseyi, en salmón del Atlántico (Salmo salar) infestado. Se evaluó en forma histopatológica la toxicidad de A3 durante siete días, a través de distintas dosis (0, 0,24, 0,47, 2,37, 11,86 y 23,71 mg kg-1) inyectadas por vía intra-peritoneal en Salmo salar, en tejidos de cerebro, intestino, piel, hígado y músculo, al final de cada tratamiento, mientras que el efecto de A3 contra los piojos de mar fue evaluado usando 250 salmones del Atlántico en un sistema de flujo abierto de agua de mar (~13°C). El efecto de la dosis en la dieta de los peces se evaluó a dos niveles (9 mg kg-1 y 18 mg kg-1) y con una muestra control (sin A3), por 4, 8 y 12 días, una vez alcanzado el estado maduro del piojo de mar. En forma complementaria, se evaluó el efecto de la persistencia de A3 diluido en agua marina (0,5 g L-1) a 10, 12 y 14°C, durante 0, 1, 3, 6, 10 y 15 días, donde la máxima persistencia fue de 10 días a 10°C. Los resultados permitieron concluir que las dosis de prueba sobre 0,47 mg kg-1 no tuvieron efecto tóxico en el salmón del Atlántico, pero indujeron un efecto perjudicial sobre Caligus rogercresseyi (reducción del 15% de hembras maduras para una dosis de 18 mg kg-1), lo cual podría atribuirse a alteraciones en el desarrollo embrionario del piojo de mar. A3 puede ser un potencial complemento en la alimentación de salmones, empero estudios sobre su mecanismo de acción deben realizarse previo a su uso

Air-classified faba bean protein concentrate is efficiently utilized as a dietary protein source by post-smolt Atlantic salmon (Salmo salar)

High-quality sources of protein for the formulation of feeds of carnivorous fish species such as Atlantic salmon are currently being sought. In an earlier screening trial we evaluated for the first time in Atlantic salmon (Salmo salar) the applicability of air-classified faba bean (Vicia faba) protein concentrate (BPC) inclusions in combination with soy protein concentrate (SPC) and fishmeal (FM) using parr as a model. Based on the results in parr in freshwater, the present study tested the hypothesis that BPC can effectively replace SPC and/or FM as a dietary protein source in post-smolt Atlantic salmon in seawater. The trial was designed to test nine different combinations of BPC, SPC and FM around the ideal mixture proportions modelled from data on parr (20% BPC, 46% SPC and 34% FM as percent of the total dietary protein). Somatic, physiological, biochemical and molecular parameters were assessed to determine fish performance. On average, fish grew from ~1.28kg to 2.80kg over the course of the 17week trial. Results demonstrated that a mixture of BPC, SPC and FM (208gkg−1, 193gkg−1and 85gkg−1, respectively) resulted in the highest weight gain of post-smolts without significantly altering the FCR. Specifically, fish fed the highest inclusion of BPC and lowest level of FM had final weights on average 0.24kg more than those with the lowest inclusion of BPC and highest FM. Improved weight gain was not achieved at the expense of poorer FCR, which was lower in fish fed diets with higher content of BPC and lower FM. The highest level of inclusion of BPC tested herein (~21% of feed) could replace up to 8.5% FM (from 17% to 8.5% of feed) and 10% SPC (from 29% to 19% of feed), resulting in the largest improvement in weight gain. There were no biologically significant or physiologically important effects on nutrient digestibility, enteritis scores or hepatic gene expression of dietary BPC