Search

This study examined how eco-organic feed affects the growth performance, nutrient efficiency, feed utilisation, and body composition of gilthead seabream. Six different diets were tested, including a control diet (CONT) without organic ingredients and four diets with 100% organic ingredients: trout (TRO), seabass (SBS), poultry (POU), and mix (MIX), along with a control organic diet (ORG) containing organic ingredients and 30% fishmeal. The experiment lasted 70 days, and the fish were fed twice a day, starting with an initial weight of 60.5 g. The results showed that the highest growth rates were observed in fish fed the ORG and CONT diets containing fishmeal. Conversely, the POU diet resulted in the lowest growth rate, survival rate, and highest value for feed conversion ratio (FCR). Almost all essential amino acid efficiency values were high in fish fed the ORG and CONT diets. Still, significant differences were noted in the retention efficiency of fatty acids across all diets. The retention efficiency was higher in the CONT diet, followed by the ORG diet. However, the economic conversion rate was lower for CONT, SBS, TRO, and MIX. Overall, using organic diets of animal origin impacted the growth performance of gilthead seabream, but it is still a promising approach.

A 120-day experiment investigated the new organic raw materials for Gilthead seabream (Sparus aurata) feeding on growth, nutritional parameters, digestibility, and histology. An organic control diet (CON) and three diets with 100% organic raw materials—the rest of rainbow trout, visceral Iberian pig, and insects as a protein source (TRO, IBE, and INS)—were tested. After the experiment, growth, nutritional parameters, digestibility, and histology were measured. The CON diet-fed seabream obtained the highest weight; there was no difference between the experimental diets. The crude protein content was the highest in seabream fed the TRO and INS diets. Crude fat was the highest value observed in the CON diet. High digestibility was observed in seabream-fed IBE and INS diets. Except for EAA methionine (Met), there were no static differences in retention efficiency. The diet with the highest hydrolysis rate was IBE. Diet differences were significant but had the typical healthy liver morphology of seabream. Seabream fed on the TRO and INS diets had shorter distal gut measurements. In conclusion, the full substitution of fishmeal with organic raw materials, including rainbow trout remains, Iberian pig viscera, and insects, offers several benefits in terms of digestibility, histology, and growth performance and may help improve sustainable and healthy aquaculture practices.

[EN] Fish (175 g of initial weight) were fed in triplicated groups with four diets formulated by 0% (FO 100), 75% (FO 25) and 100% (with and without probiotics, FO 0 and FO 0+) of fish oil replacement consisting of a mixture of linseed, sunflower and palm oils. After 109 days, growth and nutritional parameters were not affected by the treatment; however, fish fed with 0% of fish oil showed the lowest survival rate and without differences between the same diet with probiotics. As for biometric parameters, significant differences in the viscerosomatic index (VSI) were observed between fish fed the FO 0+ diet and the FO 100 and FO 25 diets. Results obtained from histological analysis did not detect inflammation in gut samples, while liver samples showed a remarkable steatosis in all four treatments. Total fish oil replacement produced a significant difference in the width of the lamina propria. The dietary inclusion of probiotics in the FO 0+ diet seems to favour a recovery of intestine histology. In addition, as fish oil substitution increased, the width of the lamina propria also increased. In conclusion, it is possible to affirm that the four diets administrated toSeriola dumerilidid not compromise the correct development of the animals., The financial support for this study was provided by the "Conselleria de Educacio, Cultura i Esport" of Valencian government (Reference: AICO/2015/123). We also acknowledge David Harry Rhead for their English revision.

The present study was conducted to investigate the effects of dietary fish oil replacement with a mixture of vegetable oils and probiotic supplementation on plasma biochemical parameters, oxidative stress, and antioxidant ability of Seriola dumerili. Specimens with an initial weight of 175 g were used. Four feeds were formulated with 0% (FO-100), 75% (FO-25), and 100% (FO-0 and FO-0+ with the addition of Lactobacillus probiotics) substitution of fish oil with a mixture of linseed, sunflower, and palm oils. After 109 days, no significant differences were observed in the activity of antioxidant enzymes in the liver, foregut, and hindgut, only glucose-6-phosphate dehydrogenase activity in the liver was higher in the fish fed the FO-100 diet than in those fed the FO-0 diet. No significant differences were observed in the total, reduced, and oxidized glutathione and the oxidative stress index in the liver. In addition, lipid peroxidation in the liver and red muscle values were higher in the fish fed the FO-100 diet than in the fish fed the FO-0+ diet, however, the foregut of the fish fed the FO-100 diet presented lower values than that of the fish fed the FO replacement diet, with and without probiotics. There were significant differences in cholesterol levels in the FO-100 group; they were significantly higher than those observed with the fish diets without fish oil. To sum up, fish oil can be replaced by up to 25% with vegetable oils in diets for Seriola dumerili juveniles, but total fish oil substitution is not feasible because it causes poor survival. The inclusion of probiotics in the FO-0+ diet had no effects on the parameters measured.

[EN] Aquaculture effluents with high levels of phosphorus (P) and nitrogen (N) contribute to eutrophication in the aquatic ecosystem. The environmental impact of phosphorus and N aquaculture waste may be diminished by modifying diet ingredients that improve phosphorous (P) digestibility, and therefore, reduce the P in metabolic waste. The content of P in fishmeal is high (30 g/kg), but the inclusion of fishmeal in the diet is reducing due to its high costs and limited accessibility; therefore, the addition of an inorganic P source is necessary to ensure a satisfactory level of available P in fish diets. Consequently, the present study aimed to evaluate the effect of four different inorganic P sources on P digestibility and excretion in rainbow trout (Oncorhynchus mykiss), as one of the most relevant aquaculture species. Monosodium/monocalcium phosphate with 2% of sodium source presented a P digestibility similar to monoammonium phosphate, but with lower nitrogen and phosphorus excretion into the environment, which is advantageous from a nutritional, environmental and industrial point of view (biofilters and recirculation systems in fish farms). This study was conducted to evaluate the apparent availability and P and N excretion in rainbow trout (Oncorhynchus mykiss) using different inorganic phosphorus sources. With this goal, fish (153 +/- 14.1 g) fed four inorganic P sources were assayed: monoammonium phosphate (MAP, NH4H2PO4), monosodium/monocalcium phosphate (SCP-2%, AQphos+, NaH2PO4/Ca(H2PO4)(2)center dot H2O in proportion 12/88), monosodium/monocalcium phosphate (SCP-5%, NaH2PO4/Ca(H2PO4)(2)center dot H2O in proportion 30/70) and monocalcium phosphate (MCP, Ca(H2PO4)(2)center dot H2O). Phosphorus (P) digestibility, in diets that included MAP and SCP-2% as inorganic phosphorus sources, were significantly higher than for SCP-5% and MCP sources. In relation to the P excretion pattern, independent of the diet, a peak at 6 h after feeding was registered, but at different levels depending on inorganic P sources. Fish fed an MAP diet excreted a higher amount of dissolved P in comparison with the rest of the inorganic P sources, although the total P losses were lower in MAP and SCP-2% (33.02% and 28.13, respectively) than in SCP-5% and MCP sources (43.35% and 47.83, respectively). Nitrogen (N) excretion was also studied, and the fish fed an SCP-5% diet provided lower values (15.8%) than MAP (28.0%). When N total wastes were calculated, SCP-2% and SCP-5% showed the lowest values (31.54 and 28.25%, respectively). In conclusion, based on P and N digestibility and excretion, the SCP-2% diet showed the best results from a nutritional and environmental point of view., This study has been developed under the framework of the project entitled "Improvement of the nutritional quality of aquaculture feeds through the incorporation of microalgae hydrolysates enriched in probiotic microorganisms-ALQUABIOTIC," ITC-20181099, corresponding to the FEDER INNTERCONECTA 2018 call, funded by CDTI (Centre for the Development of Industrial Technology), supported by the Ministry of Science, Innovation and Universities and co-financed by FEDER funds (European Regional Development Fund) within the 2014-2020 Intelligent Growth Operational Program.

The meagre is a carnivorous species and might be a suitable candidate species for the diversification of aquaculture in the Mediterranean region. This is based on its high growth and flesh quality. Nevertheless, there is little information available about its growth rates and nutrient requirements. The objective of this study was to determine the protein and energy requirements of juvenile meagre (Argyrosomus regius). Two trials for different weights of 53 and 188 g were conducted with rations from starvation to apparent satiation with the scope of studying its nutritional needs. In the first trial, the initial mean body weight of the fish was 53 g, and they were fed at feeding rates, measured as a percentage of the body weight, of 0, 0.75, 1.5, 2.5, 3.5, and 4.5%, with two replicates per treatment. In a second trial, another group with approximately 188 g of initial body weight was fed at feeding rates of 0, 0.5, 1.5, and 2.5%, with two replicates per treatment. The optimum thermal growth coefficient was obtained with a feed intake of 2.2% day&minus, 1 in trial A and 1.73% day&minus, 1 in trial B. The digestible protein (DP) intake for maintenance was determined as 0.57 g kg&minus, 0.7 day&minus, 1, the DP intake for maximum growth was 6.0 g kg&minus, 1, and the point for maximum efficiency in protein retention was 1.8 g kg&minus, 1. The requirement for digestible energy (DE) intake for maintenance was recorded at 25.4 kJ kg&minus, 0.82 day&minus, 1, the DE intake to maximize growth was 365 kJ kg&minus, 1, and the point for maximum efficiency in energy retention occurs with a digestible energy intake of 93 kJ kg&minus, 1. The requirements and retention efficiency of protein and energy in Argyrosomus regius tend to be within the range other fish species. The maintenance needs are in agreement with species with low voluntary activity and growth requirements in agreement with fast-growth species.

[EN] Seabass is one of the leading aquaculture species in Europe. Sensory analysis is essential for new product development. This research focused on establishing and differentiating the opinion of consumers about seabass quality obtained with organic feeding. Fish were fed for 196 days with four treatments (a control diet with 30% fishmeal and three diets with different levels of fishmeal supplemented with organic vegetable ingredients: 25%, 30% and 35%). Experimental diets were compared with commercial samples from the retail industry that were considered as "adequate quality for fish ". Two sensory analyses were carried out, check-all-that-apply (CATA) to obtain feedback on consumers' characterization towards a different type of fish evaluated and projective mapping (PM) to measure the similarity among a set of products and establish a comparison between results provided by both methods. According to the CATA results, white color, softness, meaty taste and juicy texture were considered relevant attributes, also showing a good relationship with an adequate cooked fish description. A penalty analysis confirmed that the previous characteristics were considered essential while fibrous was an undesirable attribute. The projective mapping showed a similar sensory configuration to the CATA, corroborating these findings that showed that commercial fish were placed in a position away from the rest of the treatments, and the organic diet with a higher level of fishmeal (35%) was the most distant from the control diet., This Project was subsidized by the Biodiversity Foundation 1-2020, within the framework of the Pleamar Program, co-financed by the FEMP.

[EN] Triploid, sterile Atlantic salmon (Salmo salar) could make a contribution to the development of the farming industry, but uncertainties about the performance and welfare of triploids have limited their adoption by farmers. In this study, we compared the ontogeny of digestive tract morphology and enzyme activities (pepsin, trypsin, chymotrypsin, alkaline phosphatase and aminopeptidase) of diploid and triploid Atlantic salmon. Fish were fed diets based on fishmeal (STD) or a mix of fishmeal and hydrolysed fish proteins (HFM) whilst being reared at low temperature from start-feeding to completion of the parr-smolt transformation. Fish weights for each ploidy and feed combination were used to calculate thermal growth coefficients (TGCs) that spanned this developmental period, and the data were used to examine possible relationships between enzyme activities and growth. At the end of the experiment, faeces were collected and analyzed to determine the apparent digestibility coefficients (ADCs) of the dietary amino acids (AAs). Digestive tract histo-morphology did not differ substantially between ploidies and generally reflected organ maturation and functionality. There were no consistent differences in proteolytic enzyme activities resulting from the inclusion of HFM in the diet, nor was there improved digestibility and AA bioavailability of the HFM feed in either diploid or triploid fish. The triploid salmon had lower ADCs than diploids for most essential and non-essential AAs in both diets (STD and HFM), but without there being any indication of lower intestinal protease activity in triploid fish. When trypsin-to-chymotrypsin activity and trypsin and alkaline phosphatase (ALP) ratios (T:C and T:ALP, respectively) were considered in combination with growth data (TGC) low T:C and T:ALP values coincided with times of reduced fish growth, and vice versa, suggesting that T:C and T:ALP may be used to predict recent growth history and possible growth potential., This work was supported by the Norwegian Research Council, Regional Research Fund-RFF-NORD -https://www. regionaleforskningsfond.no/ -(Grant no. 248028, VP at Nofima as project coordinator) and the Norwegian College of Fishery Science, University of Tromsø, (UiT) the Arctic University of Norway. The funder provided support in the form of salary for one author [VP] but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of this and other authors are articulated in the "author contributions" section. Publication charges for the article were provided by the Open Access publication fund of UiT, the Arctic University of Norway.

The interaction between diet and intestinal health has been widely discussed, although in vivo approaches have reported limitations. The intestine explant culture system developed provides an advantage since it reduces the number of experimental fish and increases the time of incubation compared to similar methods, becoming a valuable tool in the study of the interactions between pathogenic bacteria, rearing conditions, or dietary components and fish gut immune response. The objective of this study was to determine the influence of the total substitution of fish meal by plants on the immune intestinal status of seabream using an ex vivo bacterial challenge. For this aim, two growth stages of fish were assayed (12 g): phase I (90 days), up to 68 g, and phase II (305 days), up to 250 g. Additionally, in phase II, the effects of long term and short term exposure (15 days) to a plant protein (PP) diet were determined. PP diet altered the mucosal immune homeostasis, the younger fish being more sensitive, and the intestine from fish fed short-term plant diets showed a higher immune response than with long-term feeding. Vibrio alginolyticus (V. alginolyticus) triggered the highest immune and inflammatory response, while COX-2 expression was significantly induced by Photobacterium damselae subsp. Piscicida (P. damselae subsp. Piscicida), showing a positive high correlation between the pro-inflammatory genes encoding interleukin 1β (IL1-β), interleukin 6 (IL-6) and cyclooxygenase 2(COX-2).

BackgroundAlthough high levels of fish meal replacement by alternative protein sources have been achieved without relevant alterations in terms of growth performance, negative effects on immune status were detected. The diet and fish immunity interactions at gut level have been widely discussed, although in vivo approaches have reported several limitations. In this sense, intestine explant culture system can be a valuable complementary tool to study the interactions between pathogenic bacteria and fish gut response, and the possible influence of environmental, breeding, rearing conditions or dietary components on the responsiveness of the innate immune system in fish.The object of this study was to test the impact of total substitution of fish meal by plant protein on the intestinal health of seabream (12g) in two growth stages: phase I (90 days), up to 68 g, and phase II (305 days), up to 250g. In phase II, the effects of the long term and short exposure (15 days) to plant protein diet were determined. In order to determine the effect of plant protein feeding on the innate immune response to bacterial pathogens, and an ex vivo procedure of intestine explants culture was implemented.ResultsFish showed less tolerance to dietary plant protein in phase I than in phase II, while the ex vivo assays indicated that the intestine from fish fed at short-term plant diets showed a higher immune response than at long term feeding.In relation to the immune response to bacterial challenge, a significant expression in pro-inflammatory cytokines IL-1β and IL-6 after 6 hours of exposure to V. algynoliticus, while COX-2 expression was significantly induced by P. damselae subsp. pisicida, showing positive high correlation between them.ConclusionsA differential health status was observed depending of growth stage, being stricter to the plant protein inclusion the younger fish. The new experimental system based on fish intestinal explants culture has been successfully implemented, becoming an effective methodology for ex vivo studies. Under ex vivo conditions, the bacterial challenge induced inflammatory and immune intestinal response, responding stronger those intestine of fish fed during a short-term with a total substitution of fish meal.

The present study evaluated the effects of wash-out on the fatty acid (FA) composition in the muscles of Mediterranean yellowtail. After 109 days during which fish were fed either a fish oil (FO)-based diet (FO 100) or a diet (FO 0) in which FO was completely substituted by vegetable oils, all fish were subjected to a wash-out with FO 100 diet for 90 days. The FA profile of muscles in fish fed FO 0 diet at the beginning of the experiment reflected that of dietary vegetable oils, rich in linoleic acid (LA), and &alpha, linolenic acid (ALA), and was deficient in AA (arachidonic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). No essential FA were fully restored in fish previously fed FO 0 diet on 45th or 90th day of wash-out. At the end of wash-out, the FA composition showed that AA, EPA, and DHA in the white muscles increased by +33%, +16%, and +43% (p &lt, 0.001), respectively. Similarly, AA and DHA in the red muscles increased by +33% and +41% respectively, while EPA remained similar to fish fed FO 0 diet exclusively. Therefore, a 90-d wash-out can partially improve the FA profile in muscles of Mediterranean yellowtail previously fed vegetable oil-based diets.

[EN] The apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, and amino acids in fish, krill, squid, meat, defatted krill, soybean, wheat gluten, wheat, camilina, pea, sunflower, and fava bean meals were determined for juvenile Seriola dumerili. The results showed that the ADC of dry matter for yellowtail ranged from 57.7 to 87.2% for animal ingredients and from 42.2 to 82.2% for plant ingredients. An ADC of protein exceeding 90% was observed in fishmeal, while camilina meal and fava bean meal presented the lowest values. Pea meal presented the lowest lipid ADC (83.5%). The availabilities were generally higher in animal ingredients than those in vegetal ones. Except camilina and fava bean meal, the other ingredients appear to be favorable for S. dumerili diets, especially the ones from animal sources. Lower case chemical score values (minimum value from amino acid ratios [AARs]) were obtained in some vegetal ingredients (14¿18%), while the highest ones were observed in marine ingredients (69¿88%). According to Oser's Index, the most balanced protein for yellowtail with regard to essential amino acids was in krill, defatted krill, and fishmeal (92¿96%). So, animal sources are suitable as protein ingredients, but they could be enhanced through some essential amino acid supplementation., This project was financed by the “Ministerio de Ciencia e Innovación” (reference AGL2011-30547-C03).

[EN] Purpose Studying the efect of citrus pulp silage in the growth performance, amino acid retention of sharpsnout sea bream juveniles. Methods Citrus pulp is an energy and protein source that has been used to replace wheat meal in Diplodus puntazzo fngerlings; 96 fsh of 21.5±0.67 g were nourished with two experimental diets for 105 days. The control diet (CON) contained 421.6 g/kg of protein and 22.6 MJ/kg of energy. The citrus pulp diet (CPD) included 442.7 g/kg of protein and 22.02 MJ/ kg of energy. Results At the end of this trial, the CPD did not afect the growth parameters, but the feed efciency values exhibited statistically signifcant diferences, with those fsh fed the CPD having higher values, possibly due to the presence of limonene in the diet. The CPD also resulted in a reduction in amino acid (AA) content due to the protein being bound to fbre; this consequence did not afect the fnal fsh AA profle. For AA retention, only arginine displayed signifcant diferences, although the rest of the AAs also showed efects of AA reduction from the CPD. Conclusion Citrus pulp silage can be used in D. puntazzo feeding, without adverse in the growth performance and the amino acid profle, although it did cause a reduction in feed efciency

[EN] The search for new sustainable aquafeeds for the species with greater economic importance, such as the gilthead sea bream in Europe, is one of the main challenges in the aquaculture sector. The present work tested fishmeal replacement by a mixture of plant meals at different levels, as well as the use of marine by-products with attractant properties and high-quality protein in high plant protein diets. In order to do that, effects on growth and biometric parameters, digestibility, amino acid retention, excreted ammonia and proteases and amylase activity were assessed, using six different diets: FM100 (100% of protein provided by fishmeal), FM50 (50% of replacement), FM25 (75% of replacement) and FM0 (100% of replacement), but also FM25+ (75% of replacement and 15% of squid and krill meal inclusion), and FM0+ (100% of replacement and 15% of squid and krill meal inclusion). In group FM0, a clear impact of dietary changes was observed on growth, survival and ammonia excretion. Amino acid retention in group FM0+ was also significantly affected, which can be explained by the limited content of certain amino acids in this diet. On the other hand, no significant differences were observed in most biometric parameters or in enzyme activity. In conclusion, complete fishmeal replacement can be achieved by using a mixture of plant-based sources, but supplementation with complementary marine ingredients can prevent detrimental effects on growth, survival, nutritional parameters and protein metabolism., This work was supported by the Vicerrectorat d'Investigacio, Innovacio i Transferencia of the Universitat Politecnica de Valencia, within the project Aquaculture feed without fishmeal (SP20120603). URLs of funder: http://www.upv.es/entidades/VIIT/info/indexnormalc.htm. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Las muestras de animales plagas fueron colectadas, secadas y molidas. Estas fueron analizadas para determinar su contenido en proteína, cenizas y aminoácidos. Los análisis bromatológicos mostraron que Achatina fulica y Pieris brassica, contienen más proteína bruta, (PB) (779.2 y 812.2 g/kg) en comparación a Phyllophaga spp. y Spodoptera frugierda (432. 5 y 445.7 g/kg). Comparando el perfil de aminoácidos, A. fulica y P. brassica obtuvieron los niveles más altos en la mayoría de los amino ácidos esenciales (AAE) que la torta de soya y en el caso de A. fulica, éste exhibió valores más altos que la harina de pescado en arginina, cisteina, glicina, serina y tirosina. Observando la relación de AAE/AANE (amino ácidos no esenciales) en las harinas, sólo S. frugiperda presentó valores similares a la harina de pescado (0.85). Todas las harinas de animales plagas presentaron una reducción en la cuantificación de amino ácidos en relación con los valores de PB obtenidos por el método de Kjeldahl, esta reducción se encontraba entre 28.6 y 38.0%. Esta disminución podría deberse a la combinación entre la proteína y la quitina que se encuentran en el cuerpo de los insectos. A pesar de esta reducción la cuantificación de amino ácidos de los animales plagas podría ser una buena alternativa para su uso en la alimentación de monogástricos, especialmente para peces y crustáceos.

9 pages, 8 figures, Marine aquaculture takes advantage of marine ecosystem services to produce goods that can be relevant from a food security point of view. However, this activity is subject to multiple stressors as the ones exerted by global climate change. Local stressed conditions due to environmental drivers may be exacerbated by the COVID19 pandemic crisis. In this paper we analyze the pre-COVID-19 situation in two Spanish regions with the highest aquaculture production, Galicia and the Valencian Community. The incidence of storms, heat waves and mussel farming closure were analyzed, and surveys were used to define the perception of producers in terms of economic problems derived from COVID-19 and synergistic environmental concerns. Also the temporal trend of mussel production was analyzed. Spanish marine aquaculture has been intensively subjected to climatic stressors that made it more vulnerable to COVID-19, showing some weakness in terms of production as can be seen in mussel production and fresh consumption. Anyway, extensive aquaculture and aquaculture developed by Integrated Multi-Trophic Aquaculture (IMTA) was reported as somewhat more resilient to the impact of COVID-19. In order to ensure the environmental and economic sustainability of marine aquaculture - under a future uncertain pandemic scenario – our outcomes underline the need for more resilient adaptation programs and recovery plans taking into account the climate change effects, M.C.M.’s research activity was supported by the European Union’s Horizon 2020 Research and Innovation pro- gramme under the Marie Skłodowska-Curie Action (Grant agreement no. 835589, MIRROR Project)

[EN] A digestibility trial was conducted to evaluate the effect of fishmeal (FM) replacement with meat and bone meal on diets digestibility, digestive enzymes activity, and microbiota modulation in gilthead seabream (Sparus aurata) juveniles fed diets (45% CP; 20% CL) including 0, 50, and 75% of protein from MBM (diets MBM0; MBM50; MBM75). The ADC of protein was high and unaffected by dietary MBM level, whereas the ADC of energy was higher with diet MBM50 than with MBM0. The ADC of essential amino acids was also high and not affected by diet composition, except for the ADC of phenylalanine and tyrosine, which were lower in diet MBM75 than in the other diets. Pepsin, trypsin, chymotrypsin, lipase, and total alkaline proteases activities were all unaffected by diet composition. Dietary inclusion of MBM modulated gastrointestinal tract microbiota, decreasing the average number of operational taxonomic units and microbial richness. Dietary MBM inclusion promoted an increase of Vibrio, Bacillus, and Mycobacterium genera, whereas colonization by Staphylococcus and Corynebacterium decreased. Overall, present results indicate that up to 75% of FM protein can be replaced by MBM protein in diets for gilthead seabream juveniles without major adverse effects on diet digestibility and digestive function. However, gastrointestinal microbiota was modulated, and further research should be conducted to evaluate the impact of gastrointestinal microbiota modulation on immune and health status of gilthead seabream., This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT - Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the programme PT2020. C.R. Serra was supported by grant SFRH/BPD/101038/2014, from FCT.

The study aimed to evaluate how replacing different proportions of fish oil (FO) with vegetable oils (VO) in the diet of Mediterranean yellowtail, Seriola dumerili (Risso, 1810), affects the fatty acids (FA) signature, i.e., overall FA profile, in different tissues. A total of 225 Mediterranean yellowtail juveniles (initial live weight: 176 &plusmn, 3.62 g) were fed for 109 days with one of three diets: A control diet (FO 100), with FO as the only lipid source, or diets with 75% and 100% of FO replaced with a VO mixture. At the end of the feeding trial, the brains, muscles, livers, and visceral fat were sampled in four fish per tank (12 per treatment), and their fat were extracted and used for FA analysis. The FA signatures of red and white muscle, liver, and visceral fat tissues changed when the dietary FA source changed, whereas FA signatures in the brain were rather robust to such dietary changes. These new insights might help evaluate whether key physiological functions are preserved when fish are fed diets with low FO levels, as well as define the dietary FA requirements of Mediterranean yellowtail to improve the sustainability of the production and welfare of the fish.

The interaction between diet and intestinal health has been widely discussed, although in vivo approaches have reported limitations. The intestine explant culture system developed provides an advantage since it reduces the number of experimental fish and increases the time of incubation compared to similar methods, becoming a valuable tool in the study of the interactions between pathogenic bacteria, rearing conditions, or dietary components and fish gut immune response. The objective of this study was to determine the influence of the total substitution of fish meal by plants on the immune intestinal status of seabream using an ex vivo bacterial challenge. For this aim, two growth stages of fish were assayed (12 g): phase I (90 days), up to 68 g, and phase II (305 days), up to 250 g. Additionally, in phase II, the effects of long term and short term exposure (15 days) to a plant protein (PP) diet were determined. PP diet altered the mucosal immune homeostasis, the younger fish being more sensitive, and the intestine from fish fed short-term plant diets showed a higher immune response than with long-term feeding. Vibrio alginolyticus (V. alginolyticus) triggered the highest immune and inflammatory response, while COX-2 expression was significantly induced by Photobacterium damselae subsp. Piscicida (P. damselae subsp. Piscicida), showing a positive high correlation between the pro-inflammatory genes encoding interleukin 1β (IL1-β), interleukin 6 (IL-6) and cyclooxygenase 2(COX-2)., The research was supported by a grant financed by the Spanish Ministerio de Economía y Competitividad AGL2015-70487-P and Generalitat Valenciana, IDIFEDER/2020/029

Simple Summary Most of the studies performed to date mainly investigated on the effects of dietary substitution of fish oil with vegetable oils on growth and fatty acid composition of edible muscle tissues. On the other hand, a few assessed how dietary lipids are retained in other tissues, such as brain, liver, and adipose tissue, which would provide further insights into the fatty acid requirements of new farmed marine fish species such as Seriola dumerili. Thus, this study evaluated how the replacement of fish oil with different proportions of vegetable oils in diets affects the tissue-specific fatty acid composition (also known as signature) of brain, muscle, liver, and visceral fat of S. dumerili. The fatty acid composition of the diet had a strong effect on the fatty acid signature of muscle, liver, and visceral fat, whereas the brain signature was less sensitive to dietary changes. These new insights contribute to identify the essential fatty acids requirements of Mediterranean yellowtail and to define the conditions under which the physiological functions in these fish are preserved when they are fed diets with low fish oil levels to guarantee the sustainability of their production and welfare. Abstract The study aimed to evaluate how replacing different proportions of fish oil (FO) with vegetable oils (VO) in the diet of Mediterranean yellowtail, Seriola dumerili (Risso, 1810), affects the fatty acids (FA) signature, i.e.; overall FA profile, in different tissues. A total of 225 Mediterranean yellowtail juveniles (initial live weight: 176 ± 3.62 g) were fed for 109 days with one of three diets: A control diet (FO 100), with FO as the only lipid source, or diets with 75% and 100% of FO replaced with a VO mixture. At the end of the feeding trial, the brains, muscles, livers, and visceral fat were sampled in four fish per tank (12 per treatment), and their fat were extracted and used for FA analysis. The FA signatures of red and white muscle, liver, and visceral fat tissues changed when the dietary FA source changed, whereas FA signatures in the brain were rather robust to such dietary changes. These new insights might help evaluate whether key physiological functions are preserved when fish are fed diets with low FO levels, as well as define the dietary FA requirements of Mediterranean yellowtail to improve the sustainability of the production and welfare of the fish.

A trial was conducted to evaluate fish meal (FM) replacement with meat and bone meal (MBM; 53% CP, 15% CL, 27% Ash) in diets for gilthead seabream (Sparus aurata) juveniles. Three extruded experimental diets were formulated (45% CP; 20% CL) to include 0, 50 and 75% of protein from MBM (diets MBM0; MBM50; MBM75). Triplicate groups of seabream (IBW = 25 g) were fed these diets to satiety for 12 weeks. Growth performance and feed efficiency were similar with the diets MBM0 and MBM50, but were lower with diet MBM75, while the opposite was true for feed intake. Whole-body composition was not affected by diets composition except for crude lipid and energy content, which were lower with the diet MBM75. Protein and essential amino acids retention were unaffected by diet composition, while energy retention was lower with the diet MBM75. In terms of economic efficiency, diets with MBM resulted in a lower production costs, with the lowest economic conversion ratio (€ kg− 1 fish produced) being obtained for the MBM diets while the maximum economic profit (€ kg fish− 1) was obtained for diet MBM50. Overall, up to 50% of FM protein can be replaced by MBM protein in diets for gilthead seabream juveniles, without compromising growth performance, feed utilization, and nutrient retention. Statement of relevance Replacing 50% of fishmeal protein improved economic return.

The present study was conducted to determine the effect of soybean oil on the performance and liver histology in Sharpsnout seabream (Diplodus puntazzo) (initial body mass 35 g). Four experimental diets were formulated containing 0%, 25%, 50%, and 75% of soybean oil substituting fish oil. Fish were fed for 84 days. Increasing the level of soybean oil had no significant effects on growth and feed efficiency parameters. Biometrics, body composition, protein efficiency, and energy efficiency were not affected by the fish oil replacement. Muscle and liver fatty acids reflected fish oil substitution. Moreover, histology did not show statistical differences among treatments. Sharpsnout seabream juveniles can be fed with diets in which fish oil has been replaced with soybean oil at up to 75% of total lipid in the diet for a period of 84 days without affecting growth, feed efficiency, biometric parameters, and body composition.

[EN] An 84-day trial was performed to assess the use of alternative protein sources in Seriola dumerili. Three diets were used, FM100 diet, as a control diet without fishmeal substitution, and FM66 and FM33 diets with a fishmeal replacement of 330 g/kg and 660 g/kg, respectively. At the end of experiment, fish fed the FM66 diet showed the no differences in growth, nutritional parameters and fatty acid composition. Heavy metals present some differences but are always lower than risk levels. In sensory analysis, differences between diets appeared in pH and color, and also in some texture parameters between FM33 and the other two diets. No differences appeared between diets related to flavor. In summary, long periods of feeding with high fish meal substitution diets, affects Seriola dumerili growth; despite this the quality of the fillet was not affected even with a 66 % of substitution., This project was financed by "Generalitat Valenciana. Ayudas para grupos de investigacion consolidables."

In this work the effect of partial or total replacement of fishmeal by plant protein sources and krill and squid meal on growth performance and shelf-life of gilthead sea bream was evaluated. Plant protein dietswith 50 g kg&minus, 1 of krill and 100 g kg&minus, 1 of squid were supplemented with synthetic amino acidsand at the end of the growing period weight showed no significant differences. The spoilage process of the fish was followed by physicochemical and microbiological measurements together with a colorimetric sensor array (CSA) specially designed for that purpose. The changes in the physicochemical parameters and microbial growth showed that shelf-life of samples were in all cases lower than ninedays. The CSA was not able to show significant differences between both diets, confirming the physicochemical and microbiological results. The fact that the type of feed had no effect on the freshness parameters studied demonstrates that total fishmeal replacement with plant protein blends in the proportions used in this work could be an excellent alternative for feed formulation in aquaculture.

[EN] In recirculating aquaculture systems, performance of nitrifying biofilters for total ammonia nitrogen (TAN) removal from the culture water and thus minimizing eutrophication depends on numerous elements of design. In this article the combined effect of three of these process parameters (temperature, hydraulic loading and TAN load) is evaluated. Ammonia removal rates (N-TAN divided by biofiltration area and day) were measured for every combination of five different temperatures, three different hydraulic loadings and three different ammonia loads. Every one of the process parameters were influential on nitrification rates and the lowest process parameters values corresponded with significantly lower N-TAN removal rates. A significantly higher mean N-TAN removal rate (0.241 gN-TAN removed m¿2 day-1) was found for the combination of the highest water temperature (27¿°C), the highest hydraulic loading (11 m3¿m¿2¿h-1) and the highest TAN load (9 gTAN m-3 day-1), suggesting a positive synergy of the three process parameters on the achievement of greater biofilter performances., This research work was made possible by the funding of the national project "Design of a recirculating aquaculture system for aquaculture plants (2011-2014)" by Ministry of Science and Innovation, Spain.

[EN] Diploid and triploid Atlantic salmon, Salmo salarwere fed high-protein, phosphorus-rich diets (56-60% protein; ca 18g phosphorus kg(-1) diet) whilst being reared at low temperature from start-feeding until parr-smolt transformation. Performances of salmon fed diets based on fish meal (STD) or a mix of fishmeal and hydrolysed fish proteins (HFM) as the major protein sources were compared in terms of mortality, diet digestibility, growth and skeletal deformities. Separate groups of diploids and triploids were reared in triplicate tanks (initially 3000 fish per tank; tank biomass ca. 620 g) from 0-2745 degree-days post-start feeding (ddPSF). Growth metrics (weight, length, condition factor) were recorded at ca. 4 week intervals, external signs of deformities to the operculum, jaws and spinal column were examined in parr sampled at 1390 ddPSF, and external signs of deformity and vertebral anomalies (by radiography) were examined in fish sampled at the end of the trial (2745 ddPSF). The triploid salmon generally had a lower mass per unit length, i.e. lower condition factor, throughout the trial, but this did not seem to reflect any consistent dietary or ploidy effects on either dietary digestibility or the growth of the fish. By the end of the trial fish in all treatment groups had achieved a weight of 50+ g, and had completed the parr-smolt transformation. The triploids had slightly, but significantly, fewer vertebrae (Triploids STD 58.74 0.10; HFM 58.68 0.05) than the diploids (Diploids STD 58.97 0.14; HFM 58.89 0.01), and the incidence of skeletal (vertebral) abnormalities was higher in triploids (Triploids STD 31 0.90%; HFM 15 1.44%) than in diploids (Diploids STD 4 0.80%; HFM 4 0.83%). The HFM diet gave a significant reduction in the numbers of triploid salmon with vertebral anomalies in comparison with the triploids fed the STD diet possibly as a result of differences in phosphorus bioavailability between the two diets. Overall, the incidence of skeletal deformities was lower than reported in previous studies (Diploids 20+%, Triploids 40+%), possibly as a result of the combination of rearing at low-temperature and phosphorus-rich diets being used in the present study., This work was supported by the Norwegian Research Council, Regional Research Fund - RFF-NORD (Grant no. 248028) and the Norwegian College of Fishery Science, University of Tromso, (UiT) the Arctic University of Norway. Funding agencies played no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

[EN] A 154-day trial was performed to assess the use of an alternative protein blend (corn gluten, krill and meat meal) as a substitute for fishmeal in diets for juvenile yellowtail, using four isolipidic (140 g/kg) and isoenergetic diets (24 MJ/kg) with the same digestible protein content (50%). The control diet was FM100, without replacement, and in FM66, FM33 and FM0, fishmeal was replaced at 33 g/kg, 66 g/kg and 100 g/kg, respectively. At the end of the experiment, no differences in growth parameters were observed. Fish fed the FM0 diet exhibited the lowest survival (23%). This high mortality may be due to different factors, such as a dietary amino acid imbalance or some antinutrient factors contained in the alternative ingredients. Feed intake, feed conversion ratio, digestible protein intake and protein efficiency ratio were similar in all diets. However, digestible energy intake and protein efficiency retention were lowest in fish fed the FM0 diet. Apparent digestibility coefficients for protein, energy and amino acids diminished as a substitution for fishmeal increased. Significant differences were observed in the diet whole-fish body profile amino acid retention (AAR) ratio for the seven essential amino acids. In summary, total fishmeal replacement by the blend assayed was not feasible for yellowtail. The FM66 diet resulted in good growth, high survival and good nutrient efficiency, "Ministerio de Ciencia e Innovacion" of the Spanish government, Grant/Award Number: AGL2011-30547-C03-02, Ministerio de Ciencia e Innovacion" of the Spanish government, Grant/Award Number: AGL2011-30547-C03-02

[EN] A feeding trial was carried out to assess the effect of partially replacing fish meal (FM) by Black soldier fly pre-pupae meal (HM) in diets for European seabass Dicentrarchus labrax juveniles. A FM-based diet was used as a control and three other diets were formulated to include 6.5%, 13%, and 19.5% of HM, replacing 15%, 30% and 45% of FM respectively. Each diet was fed to triplicate groups of fish (initial weight: 50 g) for 62 days. At the end of the trial, there were no differences among groups in growth performance or feed utilization. Plasma metabolic profiles also remained unaffected, except that plasma cholesterol was reduced with dietary HM inclusion. The apparent digestibility coefficients (ADC) of protein, lipids, dry matter, organic matter, and energy were generally high, and not affected by the dietary treatment. The ADC of arginine, histidine, and valine were higher in HM diets when compared to the control. Amylase and protease activities were not affected by dietary HM, while lipase activity was lower in HM 6.5 diets than in the control and HM 19.5 diets. In conclusion, up to 19.5% of HM, corresponding to 22.5% of total dietary protein, may successfully replace FM in diets for juvenile European seabass, without adverse effects on growth performance, feed utilization or digestibility., This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT - Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the programme PT2020. We would like to express our thanks to P. Correia for assistance during the growth and digestibility trial. Magalhaes, R. was supported by a VEGICOR-AMINOAQUA project grant (ref. 31-03-05-FEP-43)

[EN] The digestive tract, particularly the intestine, represents one of the main sites of interactions with the environment, playing the gut mucosa a crucial role in the digestion and absorption of nutrients, and in the immune defence. Previous researches have proven that the fishmeal replacement by plant sources could have an impact on the intestinal status at both digestive and immune level, compromising relevant productive parameters, such as feed efficiency, growth or survival. In order to evaluate the long-term impact of total fishmeal replacement on intestinal mucosa, the gut mucosa proteome was analysed in fish fed with a fishmeal-based diet, against plant protein-based diets with or without alternative marine sources inclusion. Total fishmeal replacement without marine ingredients inclusion, reported a negative impact in growth and biometric parameters, further an altered gut mucosa proteome. However, the inclusion of a low percentage of marine ingredients in plant protein-based diets was able to maintain the growth, biometrics parameters and gut mucosa proteome with similar values to FM group. A total fishmeal replacement induced a big set of underrepresented proteins in relation to several biological processes such as intracellular transport, assembly of cellular macrocomplex, protein localization and protein catabolism, as well as several molecular functions, mainly related with binding to different molecules and the maintenance of the cytoskeleton structure. The set of downregulated proteins also included molecules which have a crucial role in the maintenance of the normal function of the enterocytes, and therefore, of the epithelium, including permeability, immune and inflammatory response regulation and nutritional absorption. Possibly, the amino acid imbalance presented in VM diet, in a long-term feeding, may be the main reason of these alterations, which can be prevented by the inclusion of 15% of alternative marine sources. Significance: Long-term feeding with plant protein based diets may be considered as a stress factor and lead to a negative impact on digestive and immune system mechanisms at the gut, that can become apparent in a reduced fish performance. The need for fishmeal replacement by alternative ingredients such as plant sources to ensure the sustainability of the aquaculture sector has led the research assessing the intestinal status of fish to be of increasing importance. This scientific work provides further knowledge about the proteins and biologic processes altered in the gut in response to plant protein based diets, suggesting the loss of part of gut mucosa functionality. Nevertheless, the inclusion of alternative marine ingredients was able to reverse these negative effects, showing as a feasible option to develop sustainable aquafeeds., The first author was supported by a contract-grant (Contrato Pre doctoral para la Formacion de Profesorado Universitario) from Subprogramas de Formacion y Movilidad within the Programa Estatal de Promocion del Talento y su Empleabilidad of the Ministerio de Educacion, Cultura y Deporte of Spain.

This study investigates the effect of digestible protein levels in experimental diets for meagre (Argyrosomus regius). A group of 253 fish, 52 g of mean weight, was distributed in 12 tanks, three replicates per treatment. Four isolipidic diets (170 g kg(-1) crude lipid) with different digestible protein levels (350 a kg(-1), 430 g kg(-1), 490 g kg(-1) and 530 g kg(-1)) were formulated using commercial ingredients. The trial lasted 62 days. Meagre fed diets 430, 490 and 530 g kg(-1) obtained higher TGC (2.47, 2.57, 2.69 x 10(-3), respectively) than fish fed diet 350 g kg(-1) (2.14 x 10(-3)). Group of fish fed diet with 350 g kg(-1) DP showed the lowest ammonia excretion level. According to the in vitro digestibility trial diets with 350 and 430 g kg(-1) DP released less amino acids in comparison with diet with 49% DP, although in vivo digestibility test did not show significant differences among diets 430, 490 and 530 g kg(-1) DP. Using the quadratic regression, optimal digestible protein intake according to the ECR for rearing juvenile meagre was recorded in 0.8 g DP/100 g fish and day., This research was supported by grants from the Generalitat Valenciana (Spain). This document was revised by Nicholas James Cain 28.12.2012.

[EN] The energy and protein requirements for gilthead sea bream were studied until commercial weight. Gilthead sea bream with different body weights (from 24 to 422 g) were fed from starvation to apparent satiation, studying protein and energy in the interval of 21¿25 °C. Energy recovery (ER) was expressed in relation to the digestible energy intake (DEI), ER = 173.1 ∗ (1 − e(− 0.00407 ∗ (DEI-59.84))), and protein deposition (PD) was expressed with regard to digestible protein intake (DPI), PD = 2.97 ∗ (1 − e(− 0.152 ∗ (DPI-1.393))). Maintenance needs in summer conditions were found to be 1.393 g kg− 0.7 day− 1 of the digestible protein intake and 59.84 kJ kg− 0.82 day− 1 of the digestible energy intake. The response curves to the graded levels of intake of energy and protein should allow the diet formulation under several growth conditions and all sizes until commercial weight. Statement of relevance The feed conversion rate in Sparus aurata is not yet optimized, showing high values in farms. The knowledge of the efficiencies at different feeding rate, for the whole range of commercial weights, until 450 g, should help to improve the efficiency of feeding., Ignacio Jauralde Garcia was supported by Fundacion Alfonso Martin Escudero, Madrid, Spain. We are also grateful to Ralph Wilk for the English review. The authors wish to acknowledge Dr. Rodolofo Ballestrazzi of the Universitat degli studi di Udine for his support to Ignacio Jauralde during his stay in Italy.

[EN] Four diets for sharpsnout sea bream juveniles (14 g body weight) with four levels of air-processed pea protein concentrate (PPC) (0, 160, 320 and 487 g/kg diet) were tested in triplicate. The experimental diets were isonitrogenous (43% crude protein) and isolipidic (19% ether extract) and the fish were fed to satiation twice a day. After 125 d, fish growth was diminished by the inclusion of PPC. Feed conversion did not show significant differences in any treatment. Neither the body analyses nor the protein and individual essential amino acid retention efficiencies were affected by the inclusion of PPC in the diet. However, histological gut examinations revealed noticeable differences. Fish fed the diet with the highest inclusion level of PPC presented the longest villous length and the most goblet cells, and the width of the lamina propria increased in the anterior intestine. Although no negative changes in nutritive parameters were detected, these alterations might affect nutrient transport, with negative consequences for fish growth. It was concluded that the PPC in the amounts tested here is an inappropriate substitute for fishmeal in diets for sharpsnout sea bream juveniles., This work was supported by the Generalitat Valenciana; Fisheries Unit of the Valencian Regional Government and Ministerio de Agricultura, Alimentacion y Medio Ambiente (JACUMAR, Spain).

The use of carob seed germ meal (CG) as a substitute for fish meal was evaluated in fingerlings (average weight 10g) of gilthead sea bream fed isonitrogenous (46% Crude Protein, CP) and isolipidic (19.5% Crude Lipid, CL) diets containing four CG levels (0, 17, 34 and 52%). The duration of the trial was 83days. The diets were tested in triplicate, and the fish were fed to satiation twice daily. The apparent protein and energy digestibility coefficients decreased in response to the dietary inclusion of CG. The decreases in the values of the ADC ranged from 93% for the 0 diet to 80% for the 52 diet. The amount of digestible Arg in the diets increased with the inclusion of CG, from 3.2g Arg 100g -1 in the 0 diet to 4.81g Arg 100g -1 in the 52 diet. The digestible Arg content increased in the diets because the amounts of the remaining digestible amino acids decreased. The fish reached weights of 72, 72, 69 and 53g on the 0, 17, 34 and 52 diets, respectively. The 52 diet gave the lowest specific growth rate (SGR, 1.95%day -1) relative to those found for the other three diets (2.32%day -1). The 52 diet produced the least satisfactory results for feed intake (FI) and the food conversion ratio (FCR) (2.23g 100gfish -1day -1 and 1.38, respectively). The efficiency of retention of His, Phe and Leu in the fish fed the 52 diet showed the lowest values (17.3, 25.5 and 28.5%, respectively), but the efficiency of retention of Met in the fish fed the 52 diet showed the highest value (48.2%).In the distal intestine and liver, histological alterations were found in the fish fed the 34 and the 52 diets. In fish fed the 52 diet, the mucosal fold was significantly shorter and thinner and exhibited a smaller number of goblet cells. These changes could affect nutrient uptake by modifying the digestibility of the diet. The histology of the liver did not show severe degradation in any treatment. The results of the present experiment demonstrated that CG can be included at levels up to 34% in diets for short term feeding of gilthead sea bream without any adverse effects on fish growth and nutritive parameters., Present work was financed by AGROALIMED and GV/2010/046 (Conselleria de Agricultura, Pesca y Alimentacion, Generalitat Valenciana).

Summary The suitability of defatted soybean meal as a substitute for fishmeal was assessed in juvenile (25 g, average) tench, Tinca tinca, by feeding them diets containing 25 (S25), 37.5 (S37.5) and 50% (S50) soybean meal for 150 days. Soybean meal inclusion increased the relationship between essential and non-essential amino acids. Fish were hand-fed to apparent satiation; the feed intake ratio was not dependent upon the dietary soybean level. Survival was over 95% and unaffected by treatment. Growth was reduced at higher soybean meal levels. After 150 days, average weight for the fish fed soybean diets S25, S37.5 and S50 was 65.6, 59.2 and 51 g, respectively. Growth performance was evaluated on the basis of specific growth rate (SGR), final biomass, feed conversion ratio (FCR), and feed intake (FI). Maximum SGR (0.61–0.64) and final biomass (3022–3156 g) were recorded in tench fed diets containing 25 and 37.5% soybean meal. Nutritional parameters such as feed intake and feed conversion ratio were not affected by the soybean meal. Body composition was similar for tench fed the three different diets.

A trial of 218 days of duration was carried out to assess the use of pea protein concentrate (PPC) as a substitute for fish meal in diets for juvenile gilthead sea bream (52 g average initial weight), using four diets (0, 16, 32 and 48) with PPC inclusion levels of 0, 162, 325 and 487 g kg−1, respectively. At the end of the trial, the fish reached weights of 397, 385, 383 and 355 g for 0, 16, 32 and 48 diets, respectively; diet 48 gave the lowest specific growth rate (SGR, 0.88% per day) but 0%, 16% and 32% PPC did not present statistical differences. Feed conversion ratio (FCR), protein efficiency ratio (PER) and body composition were not affected by the diets. Digestible protein retention was significantly higher with the 0% diet, but no energy retention differences were observed. Retention rates of ingested and digestible amino acids were very similar; in general, the retention of essential amino acids decreased as dietary PPC increased, and lysine retention was the highest and phenylalanine retention was the lowest. From the results of this experiment, it may be concluded that fish meal can be replaced up to 32% by PPC in sea bream without negative effects on fish weight gain, FCR and PER.

The suitability of sunflower meal (SFM) as a substitute for fish meal was evaluated in sharpsnout sea bream fingerlings (14 g) by feeding diets in which 0, 10, 20 or 30% of crude protein provided by fish meal was substituted with SFM. The experiment lasted 125 days and survival at the end of the experiment was 95%. The effect of SFM level on growth parameters were not significant ( P

Partial replacement of fish meal by a vegetable mixture (Pea Protein Concentrate (PPC) and Rice Protein Concentrate (RPC)) was carried out in on-growing gilthead seabream (initial average weight 174 g). The experimental diets were isoproteic (48% CP) and isolipidic (18%) with 0, 30, 60 and 90% of fish meal substitution, supplemented with Methionine and Lysine. Fish were distributed in 12 tanks with 20 fish per tank. At the end of the trial (80 days), fish survival was 90% and there were no differences in growth parameters except for fish fed the 90% (326 g and SGR: 0.78% day− 1) diet. No significant differences were found in feed intake ratio (FI), which was around 1.70 to 1.96 g 100 g fish− 1 day− 1, feed conversion ratio, around 1.9 to 2.4 and protein efficiency ratio, which ranged from 0.96 to 1.2. No statistical differences were observed in biometric parameters. In the retention of amino acids ingested there were no statistical differences among diets, although fish fed the 60 diet obtained the highest values in all EAA compared with other diets. In both ingested and digested amino acids, a higher retention of His and lower retention of Met was observed. Regarding sensory analysis, there were no statistical differences in triangular test for fish fed the various diets.