Search

[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.

[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).

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.

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] 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)

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.

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.

Six isonitrogenous [450 g kg−1 crude protein (CP)] and isoenergetic diets (23 kJ g−1) with six levels of defatted soybean meal inclusion (0, 132, 263, 395, 526 and 658 g kg−1) in substitution of fish meal were evaluated in gilthead sea bream of 242 g initial weight for 134 days. Fish fed diets S0, S13, S26 and S39 had a similar live weight (422, 422, 438 and 422 g, respectively) but fish fed diets S53 and S66 obtained the lowest final weight (385 and 333g, respectively), and similar results were presented in specific growth rate (SGR). Fish fed diets S53 and S66 also obtained the highest feed conversion ratio (FCR). Quadratic multiple regression equations were developed for SGR and FCR which were closely related to dietary soybean level. The optimum dietary soybean levels were 205 g kg−1 for maximum SGR and 10 g kg−1 for minimum FCR. Sensorial differences were appreciated by judges between fish fed S0 and S39 soybean level, but after a re-feeding period of 28 days with diet S0, these differences disappeared.

Background. The aim of this work was to study the growth of juvenile dentex fed on cooking-extruded diets, determine the level of substitution of fishmeal by soybean meal may be without affecting the growth in this species and its digestibility. Materials and methods. The availability of defatted soybean meal as a substitute for fish meal was evaluated in juvenile (41 g on average) dentex by feeding diets containing 0%–60% soybean meal, for 97 days. Results. Survival at the end of the experiment was high (80%) except for the fish fed diets with 50% and 60% substitution. Growth, feed gain ratio, and protein efficiency ratio (PER) were slightly reduced at higher soybean meal levels. Fish fed diets containing 0% to 40% of soybean meal grew significantly more and FCR was lower than fish fed other diets. No differences were obtained for protein digestibility coefficients of experimental diets (20%, 30%, 40%, and 50% SBM). Conclusion. The results confirm the best protein level for optimum growth seems to be around 50% and 12% lipid level, and maximum soybean meal substitution of 40%.

Two parallel experiments were conducted to evaluate the effect of partial substitution of fish meal by two different animal protein sources, blood meal (B) and haemoglobin meal (H) at 0, 50 and 100 g kg−1 of level inclusion in diets for gilthead sea bream, considering a long feeding period for juveniles (Trial 1) and a short feeding period (Trial 2) for on‐growing fish. In Trial 1, 33 g juveniles were fed for 242 days and the fish fed with 5% and 10% of haemoglobin dietary inclusion obtained less growth, although feed efficiency, protein efficiency ratio and muscle composition were similar in all diets. In Trial 2, 179 g initial weight fish were fed for 164 days and growth of fish fed H10 showed the lowest growth, although nutrient efficiency and muscle composition were not affected significantly. The results of these experiments demonstrated that blood meal can substitute fish meal (up to 10%) with no effect on performance, but may lead to sensory differences compared with fish fed diet 0, while the inclusion of 5% blood meal had no effect on growth or sensory characteristics. Fish fed 10% haemoglobin inclusion had the poorest growth values.

[EN] This study evaluated liver and gut alterations of gilthead sea bream, Sparus aurata L., fed diets in which 12 fish meal was substituted by a mixture (M) of pea protein concentrate (PPC) and rice protein concentrate 13 (RPC). Histological studies were conducted to evaluate the possible changes produced by four 14 experimental isolipidic (18%) and isoproteic (48%CP) diets with 30, 60 and 90% of fish meal substitution 15 by a pea and rice mixture and compared with a control diet (0%). 16 The results obtained in the present histological study showed significant changes especially in the case of 17 the 90% substitution in parameters such as thickness of the layers, goblet cells and villi measurements. 18 Structural integrity of the gut would not be significantly affected by a diet of up to 60% substitution. The 19 alterations observed in the liver could not only be attributed to diet but also to possible individual variations., This study was supported by the Universitat Politecnica de Valencia (UPV PAID-06-08).

The utilisation of sunflower meal as a substitute for fish meal was evaluated in juvenile (44 g ± 4.6 on average) gilthead sea bream fed diets containing four levels of sunflower meal (0, 12, 24 and 36%). The experiment was divided into two phases; in the first one (until day 90), fish reached a weight of 189, 198, 187 and 174 g, respectively, the diet containing 36% gave the lowest specific growth rate (SGR) and the diet containing 12% sunflower meal the highest. In the second phase (from day 91 to day 248), fish growth was not significantly affected by treatments. In relation to feed intake (FI) and feed conversion ratio (FCR), the diet containing 36% sunflower meal gave the worst results in both phases. There were no statistical differences in body composition, but energy and protein efficiency were lowest in fish fed the diet containing 36% sunflower meal. Sensory differences between sea bream fed diets containing 0% and 24% sunflower meal were not detected. Optimum dietary level of sunflower meal for growth and feed conversion obtained from quadratic regression was 10–12%, but when economic aspects were considered, the optimum dietary level was 14–15% sunflower meal.

Five hormonal treatments with human chorionic gonadotropin (hCG) were tested for the induction of maturation and spermiation in male farmed eels. The main aim was to optimize previously used hormonal treatments to achieve shorter induction treatments, longer spermiation periods and/or higher sperm quality. Fish treated for just 3 weeks (treatment E) or until the onset of spermiation (treatment C) showed the worst results, while the treatment consisting of weekly administration of 1.5 IU hCG g−1 fish (treatment A) induced the highest percentage of spermiating males, the highest number of sperm samples and sperm volumes and densities similar to the rest of the treatments (B: half hormone dosage, or D: biweekly administration). Evaluation of the sperm quality was performed by computer-assisted sperm analysis (CASA), considering the percentage of total motile spermatozoa, the percentage of fast and medium-velocity spermatozoa, as well as different motility parameters. Sperm samples from A-D groups showed between 44% and 54% motile spermatozoa, and between 10% and 15% fast spermatozoa, while samples from E-treated males showed 0% motile cells. No significant differences were found in the spermatozoa straight line velocity (VSL), curvilinear velocity (VCL) or the angular velocity (VAP), neither spermatozoa beating cross frequency (BCF) between A–D groups.

[EN] A quantitative analysis of the essential mineral content (mg kg−1 dry weight) was carried out in 31 samples, including molluscs, crustaceans, fish and meals in an attempt to identify those most suitable for formulating cephalopod diets. The mineral ratios (MR: content in the test sample/content in whole Octopus vulgaris) were used as index of nutritional quality. Both crustaceans and oysters presented an optimal profile that covered the macro- and microelements composition of O. vulgaris. These samples differed from the rest by their higher Ca, Mg, B, Cu and Zn contents based on a principal component analysis. Fish were deficient in macroelements, such as Na (MR: 7–42%) and Mg (MR: 22–69%), but would be good source of K, Ca and P. Most fish were also deficient in Fe, Zn and Cu, although the copper content would be the most affected (MR: 0.3–13%). Fish and krill meals showed a high content of Ca and P, although both would be deficient in Na (MR: 44–47%) and Cu (13–54%), along with K, Fe and Zn in krill and Mg and B in fish. Among the plant meals, sunflower and soybean were the most appropriate, presenting higher total content of minerals and MRs above 100% for all minerals, except Na, Cu and Zn., This project was financed by JACUMAR Spanish National Plans for Aquaculture.

The effect of different factors (protein composition, thermal treatment, presence of and acidsalt) on the potential bioavailability of amino acids (AA) in rainbow trout diets was evaluated with a gastro-intestinal model (GIM). The in vitro assay consisted in a detailed evaluation of the rates of release of individual AA, as well as of the whole and AA profile of the dyalisates produced after hydrolysis performed using enzyme extracts obtained from stomach and intestine of fish. Results were compared to values of apparent amino acid digestibility measured in vivo. In addition, two important parameters conditioning potential bioavailability of dietary protein during digestion, solubility and buffering capacity (BC) were evaluated. Protein solubility and BC were significantly affected by the presence of a vegetable protein in the diet. As a result of enzyme hydrolysis, clear differences in the rates of release of different AA's, mainly for those being target for digestive proteases (Arg, Lys, Phe) were detected. A significant correlation between total masses of AA's dialysed in vitro and their digestibility estimated from digestibility coefficients calculated in vivo was obtained although this was not possible when using values of individual AA's. The concept and framework for future assays involving in vitro-in vivo correlations is discussed.

The amino acid composition and protein levels of three species of cephalopods (Octopus vulgaris, Loligo gahi and Todarodes sagittatus), the natural diets of common octopus (O. vulgaris) and different kinds of meals were determined in order to optimise the content of these nutrients in artificial feeds. Arginine, leucine and lysine were the most abundant essential amino acids in cephalopods, while glutamate and aspartate represented the main non-essential amino acids. Arginine and leucine were the limiting amino acid in most samples, with maximum Chemical Score values for mussel (79-98 %), squid (84 %) and crustaceans (65-91 %); medium for fish (41-70 %); and minimum for meals (29-64 %). Mussel, squid, crustaceans and fish showed a high essential amino acid index according to Oser (OI: 88-99 %) suggesting a suitable amino acid balance. The protein from animal meals (fish and krill) covered all the essential amino acids except arginine and lysine in fish meal. The vegetable meal presented the worst amino acid balance (OI: 74-89 %) with several deficiencies in essential amino acids, including arginine, threonine, lysine and methionine. Supplementation with arginine or leucine and protein complementation of crustaceans and bivalves with fish or animal meal are proposed as alternatives for improving the performance of protein in feed for cephalopods. © 2012 Springer Science+Business Media B.V., Project financed by the National Marine Culture Plans of JACUMAR.

The effect of dietary protein level and protein source on growth and proteolytic activity of juvenile Solea senegalensis was studied. In Experiment 1, fish were fed on four experimental diets containing increased protein levels (36, 46, 56 and 67%). In Experiment 2, Senegalese soles were fed on five diets with partial substitution of fish meal by soybean meal, soybean protein concentrate, soybean protein isolate, wheat gluten meal or pea protein concentrate. Results prove that growth and proteolytic activity in the distal intestine of fish were affected by the quantitative increase in dietary protein. The origin of protein source used in the elaboration of experimental diets affected both the amount and composition of the alkaline proteases secreted into the intestinal lumen; however, it did not decrease animal growth. Juvenile Senegalese sole showed capability to modulate digestive protease secretion when the concentration and/or source of dietary protein were modified. Quantity and quality of dietary protein affected protein hydrolysis in Senegalese sole intestine. This study establishes that 30% fish meal protein can be replaced by soybean derivatives without affecting intestinal proteases. Replacement with wheat gluten meal or pea protein concentrate should be taken cautiously, but further research is needed to establish whether growth performance and digestive enzyme physiology of Senegalese sole are affected by plant protein-supplemented diets in a long-term trial., This work was supported by Projects INIA RTA-2007-00026-C02-01 and 02, and the European Regional Development Fund. Ana Rodiles Guerrero was financially supported by the grant "Technology in the Larval Rearing of New Species of Fish" (IFAPA, Andalusian Regional Government, Spain). The authors thank Jose I. Navas Triano, Sean Tibbetts, Joyce Milley, Toni Barros and Andres Monino for their technical assistance. The authors are grateful to Francisco Trujillo for the revision of the English language text. Part of experimental work was carried out at CEIA3 facilities.

Four isonitrogenous (42% crude protein) and isolipidic (20%) diets were formulated using four different percentages of pork fat to substitute fish oil at 0, 25, 50 and 75% to evaluate the performance, body composition, fatty acids and liver histology of sharpsnout sea bream juveniles. One hundred and twenty fish (average weight 33.4 ± 2.9 g) were randomly distributed into pens (90 l capacity). Triplicate groups were fed each test diet twice a day to apparent satiation for 84 days. No difference was observed for feeding and growth performance. The only significant difference with respect to carcass was in moisture content (P < 0.05). With respect to liver fatty acids, there were significant differences in EPA and DHA, being fish fed 75% of pork fat that obtained the lowest value. With respect to muscle fatty acids, there were significant differences in saturated fatty acids and fish fed 0% of pork fat obtained the lowest value, but in poly unsaturated fatty acids the 75% of pork fat reported the lowest value. Although in both fish muscle and liver fatty acids, fish fed 75% pork fat diet presented significant difference in n-3 highly unsaturated fatty acids and n3/n6, but in LA fish fed the 0% of pork fat diet presented the lowest value in liver and in fish muscle not only the 0% but also the 25% of pork fat diet obtained the lowest value., This research was supported by grants from the 'Planes Nacionales de Acuicultura (JACUMAR)' and Conselleria de Agricultura Pesca y Alimentacion, Valencia, Spain.

Modelling growth as a function of feeding rate (FR) could be one of the most important tools for fish farms, because this knowledge allows growth to be maximized, or the feed conversion ratio (FCR) to be minimized, thereby improving profits. All growth models should include the three principal variables involved in growth: initial body weight, temperature and feeding rate. The thermal-unit growth coefficient (TGC) already includes water temperature variation and initial body weight. Studying variation in TGC for fish fed the same diet, but at several feeding rates provides interesting information for modelling. Six different trials were conducted where gilthead sea bream of several different initial weights (24, 38, 50, 110, 220 or 289 g) were fed increasing amounts, and growth and the conversion index response were measured. The TGC response was modelled as a function of FR, and both asymptotic and quadratic responses were examined. The asymptotic model, TGC ¿ 1000 = 2.037*(1¿e (¿0.8*(FR¿0.22)), had an adjusted R2 value of 96.18, whereas the quadratic model, TGC ¿ 1000 = ¿0.381 + 1,715 ¿ FR¿0,382 ¿ FR2, had an adjusted R2 value of 96.42. Simulations of the FCR and the economical profitability index (EPI) were conducted to provide tools for maximizing efficiency and profitability, and the results suggest that these tools will be useful for future investigations., Ignacio Jauralde Garcia was supported by Fundacion Alfonso Martin Escudero, Madrid, Spain.

The economic profitability of fish meal replacement by soybean meal and pea-rice concentrate mixture, was analysed considering the economic conversion ratio (ECR) and the economic profit index (EPIst) as a proposal for evaluating the economic profitability in diets for sea bream. The optimal fish meal levels for minimizing the ECR were 33% (when soybean meal was included) and 14% (in the case of pea-rice concentrate mixture) and for maximizing the EPIst, optimal fish meal levels were 31% and 28.8%, respectively, considering the current market price of fish meal and vegetal ingredients. The EPIst, seems to be a better index than the ECR to estimate diet profitability, because it considers weight increment, feed conversion ratio, diet cost and fish sale price. A sensibility analysis was conducted, considering variations in the price of fish meal and vegetal ingredients. Finally, several multiple regressions were developed for estimating the optimal level of fish meal with each vegetable ingredient and the expected value of the economic profit as a function of the market price of both fish meal and plant protein. When fish meal prices increase, the highest beneficial level of the inclusion fish meal and the highest economic profit would be achieved with pea-rice mixture., Elsevier Language Editing Services has revised this manuscript. This work was financed with the support of Generalitat Valenciana (GV/2010/046).

Background. Our previous study demonstrated that sharpsnout seabream, Diplodus puntazzo (Walbaum, 1792), can be fed with up to 34.8% sunflower meal (SFM), with excellent results in growth parameters and feed efficiency. The aim of the current study was to test the replacement of fish meal with SFM in the diet formulation for sharpsnout seabream and to evaluate growth, nutritive parameters, amino acid retention, and body composition of the fish during the fattening period. Materials and methods. Sixteen baskets (300-L capacity), each with thirteen fish, were distributed in a recirculated saltwater system to allow four experimental diets containing 40% crude protein (CP) and 20% crude lipid (CL) with 0%, 11.7%, 23.5%, and 34.8% SFM partially replacing fish meal to be used in quadruplicate for this experiment. The fish were fed these diets ad libitum during the experiment, which lasted for 162 days. Growth, nutrition efficiency, biometrics, carcass composition, amino acid composition, and amino acid retention of the experimental fish were evaluated. Results. There were no statistical differences in the growth parameters among the treatments. However, fish fed a diet containing 34.8% SFM had the lowest feed intake (FI), lowest feed conversion ratio (FCR), and the highest protein efficiency ratio (PER). There were also no statistical differences in the biometric parameters although fish fed the diet containing 10% SFM had the lowest CP levels. Leucine was the only difference in the essential amino acid (EEA) profile with fish fed a diet containing 11.7% SFM having the lowest levels of leucine. Although there were fluctuations among the amino acid retentions, they were not statistically significant. Conclusion. SFM (up to 34.8%) can be included in the diets of sharpsnout seabream, thereby, replacing 27% of the fish meal without altering the fish growth., This research was supported by grants from the Planes Nacionales de Acuicultura (JACUMAR).

[EN] The value of defatted soybean meal as a protein source for sea bream ¢ngerlings (15.2 4.4 g on average) growing to market size (300^350 g) was evaluated by feeding extruded isonitrogenous and isoenergetic diets (46% protein and 22 MJ kg 1 ) containing 20%, 30%, 40% and 50% soybean meal considering two phases. On day 87, the ¢sh weight ranged between 66 and 81g. The speci¢c growth rate (SGR) of sea bream fed 50% soybean was lower (1.73% day 1 ) than that of ¢sh fed 20% (1.87% day 1 ) and 30% (1.93% day 1 ), but the food conversion ratio (FCR) was not signi¢cantly a¡ected, and a quadratic signi¢cant trend was observed for the feed intake (FI) in relation to the dietary soybean level. At the end of the second phase on day 309, ¢sh weight was between 303 and 349 g, but SGR and FCR were similar for all diets, and ranged between 0.64 and 0.69% day 1 , and 1.95 and 2.10% day 1 respectively. The ¢nal biometric parameters were not a¡ected by the diets, although the levels of some free amino acids in the muscle were a¡ected. Sensory di¡erences were detected by panellists in ¢sh fed diet 20% as compared those fed diet 50%, which had a less marine £avour and was less juicy. The global growth results suggest the possibility of feeding sea bream weighing less than 80 g with 30% soybean meal, and for ¢sh weighing more than 80 g, a 50% dietary soybean meal can be used until the ¢sh reach commercial weight, with no negative e¡ects on growth or feed e⁄ciency. Nevertheless, when sensory analysis and economic aspects are considered, the maximum inclusion level of soybean was 20^22%., This research was ¢nanced by Dibaq-Diproteg, S. A. The authors are grateful to Dr Debra Westall (Polytechnic University of Valencia) for her assistance in the preparation of this article.