This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
A great deal of attention has been paid to the replacement of the high levels of fishmeal present... more A great deal of attention has been paid to the replacement of the high levels of fishmeal present in commercial diets by alternative animal and vegetable protein sources. There are some contradictory data on the effects of partial or total replacement of dietary fishmeal especially regarding vegetable protein sources. The effect of technological treatments applied to the vegetable materials and the quality of the control diets are the reasons for these contradictory results. A ten week growth trial was conducted to study the effect of partial or total replacement of fishmeal by plant proteins in diets for rainbow trout. For this purpose, four practical diets were formulated: a fishmeal-based control diet, which included a brown fishmeal as the only protein source (diet C1); another diet where 5% of the brown fishmeal protein was replaced by a fishmeal protein concentrate (CPSP; diet C2); and two other diets where 50% (diet C50) and 100% (diet C100) of the fish meal protein was replaced by plant protein sources (soybean meal, fullfat soybean and corn gluten meal). The results of the growth trial showed that 50% of the fishmeal protein can be replaced by vegetable protein sources with no adverse effects on growth and feed utilization when diet C1 was used as control. However, using diet C2 as control, weight gains of trout fed the other diets were all significantly lower. Nitrogen and phosphorus balances were also estimated and results are discussed regarding the effect of diet quality on environmental impact.
Dietary conjugated linoleic acids (CLA) have been shown to alter growth rates and reduce body fat... more Dietary conjugated linoleic acids (CLA) have been shown to alter growth rates and reduce body fat storage by altering the activity of key enzymes involved in lipid metabolism, in several species, but have not been evaluated in rainbow trout. A 12-week growth trial was conducted with rainbow trout juveniles, having an initial weight of 5.3±0.03 g (mean±S.D.). Fish were fed
... Pongmaneerat, J. and Watanabe, T., 1993. Effect of extrusion processing on the utilization of... more ... Pongmaneerat, J. and Watanabe, T., 1993. Effect of extrusion processing on the utilization of soybean meal diets for rainbow trout. Nippon Suisan Gakkaishi, 59: 14071414. ... Nutritional evaluation of brown fish meals as a protein source in diets for rainbow trout. Bull. ...
This manuscript describes and evaluates the FEEDNETICS model, a detailed mechanistic nutrient-bas... more This manuscript describes and evaluates the FEEDNETICS model, a detailed mechanistic nutrient-based model that has been developed to be used as a data interpretation and decision-support tool by fish farmers, aquafeed producers, aquaculture consultants and researchers. The modelling framework comprises two main components: (i) fish model, that simulates at the individual level the fish growth, composition, and nutrient utilization, following basic physical principles and prior information on the organization and control of biochemical/metabolic processes; and (ii) farm model, that upscales all information to the population level. The model was calibrated and validated for five commercially relevant farmed fish species, i.e., gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Nile tilapia (Oreochromis niloticus), using data sets covering a wide range of rearing and feeding conditions. The...
Two trials were carried out to evaluate the apparent digestibility coefficients (ADCs) of dry mat... more Two trials were carried out to evaluate the apparent digestibility coefficients (ADCs) of dry matter (DM), crude protein (CP), lipids, starch and gross energy (GE) of six European varieties of grain legumes, namely chickpea-type Kabuli (CHK), chickpeatype Desi (CHD), field pea (FP), faba bean (FB), white lupin (WL) and chickling vetch (CV), in rainbow trout and Nile tilapia juveniles. The ADCs were measured using a reference diet and six experimental diets (700 g/kg of the reference diet and 300 g/kg of each raw grain legume) containing 10 g/kg chromic oxide as inert marker. Additionally, grain legumes were analysed for the organic acids profile. In rainbow trout, FP presented the highest ADCs of DM, CP and GE, whereas chickpeas and FB had the lowest DM, GE and starch ADC values. In Nile tilapia, the lowest values of nutrients (except starch) and energy ADCs were found for FP and CV. Nutrients and energy of chickpeas, WL and FB were better digested by tilapia, whereas FP was better digested by trout. Overall results reveal raw grain legumes as promising feed sources for both fish species.
The present study evaluated the effects of the inclusion of three seaweeds, Gracilaria vermiculop... more The present study evaluated the effects of the inclusion of three seaweeds, Gracilaria vermiculophylla (GRA), Porphyra dioica (POR), and Ulva spp. (ULV), as dietary ingredients for Nile tilapia (Oreochromis niloticus) juveniles, on the growth performance, body composition, and gut histology. Three experimental diets (GRA, POR, and ULV) were formulated to replace 10 % of whole diet by each of the three seaweeds. A control diet (CTRL) was used, without inclusion of any seaweed. Diets were fed to triplicate groups of 25 Nile tilapia juveniles, with an average body weight (ABW) of 12.1 g, in an 84-day trial. At the end of the trial, growth performance was significantly reduced (P<0.05) in fish fed the GRA diet, whereas the feed conversion ratio increased significantly in those fish. None of the treatments caused adverse effects on body composition. The inclusion of the three seaweeds in the diet led to evident changes in the fish digestive system morphology with significant reduction of villi length on GRA diet. The results obtained in this study suggest the usefulness of P. dioica and Ulva spp. to partially replace fishmeal in practical diets for tilapia juveniles up to 10 %, as no negative consequences on growth performance or body composition were observed. However, the inclusion of 10 % G. vermiculophylla seems to have a negative effect in diet palatability, reducing fish feed intake and growth performance. Keywords Nile tilapia. Alternative feed ingredients. Seaweeds. Gracilaria vermiculophylla. Porphyra dioica. Ulva spp.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
An ultrasound and image analysis non-invasive and non-destructive method for predicting skin fat,... more An ultrasound and image analysis non-invasive and non-destructive method for predicting skin fat, filet muscle fat, and whole body fat depots in live Senegalese sole (Sole senegalensis) was evaluated. The experiment was conducted with Senegalese sole of commercial market size (n = 46, mean weight 278 ± 78 g). The fishes under a mild anesthesia were placed in a rectangular metallic container and were scanned with a real time ultrasound (RTU) scanner equipped with a linear array transducer of 7.5 MHz. For all fish, four cross-sectional RTU images of the dorsal anterior filet was obtained. The RTU images were analyzed using ImageJ software to determine the fish subcutaneous fat (SF) at each section. After this, fish were killed, and the right dorsal filet of each fish was dissected in muscle and skin. These two components and the remaining of the fish were ground and homogenized for chemical analysis. The skin fat, filet muscle fat and whole body chemical fat contents were obtained. The relationships between the SF obtained from image analysis and skin fat, filet muscle fat and whole body fat were computed using simple regression and partial least squares regression (PLSR). The skin and filet muscle had lower fat than the whole body (1.5 and 4.5 versus 6.6%, respectively). Filet muscle presents the lowest fat depot (1.5%). The SF obtained from RTU and image analysis shows a mean value between 2.8 and 3.5%. All fat depots were significantly correlated with SF obtained by RTU and image analysis, with R 2 values ranging from 0.707 to 0.851 for skin fat, 0.725 to 0.802 for filet muscle fat and 0.664 to 0.760 for whole body fat. The PLSR models explained accurately the skin fat (R 2 = 0.875 and RMSEP = 0.506), filet muscle fat (R 2 = 0.800 and RSMEP = 0.117) and whole body fat (R 2 = 0.785 and RSMEP = 0.586). Our results suggest that RTU and image analysis is a practical and feasible non-invasive and non-destructive technique for in vivo fat depots prediction in Senegalese sole fish. Statement of relevance: In aquaculture, the knowledge of the body composition in live fish, particularly fat content, is important for feeding, reproduction and genetics programs. However, all those programs depend critically on quick, accurate, and above all, non-invasive methods to predict body composition in live fish. Traditionally fish body composition was determined by comparative slaughtering followed by chemical analysis. Comprehensive studies using image techniques such as real time ultrasonography (RTU) show the ability of this technique to predict fish body composition traits. This technique is non-invasive and non-destructive and therefore is very useful for use in vivo for fish body composition examinations. Our present work investigated the ability of RTU and image analysis to predict in vivo fat composition of Solea senegalensis. Through this work monitoring fat variations with time and the possibility of repeated measurements on the same individuals and on a high number of live fish throughout the life-cycle is possible. Therefore our present study has close relevance to aquaculture particularly to nutrition status of farmed fishes.
Evaluation of antimicrobials residues in farmed gilthead seabream (Sparus aurata) after administr... more Evaluation of antimicrobials residues in farmed gilthead seabream (Sparus aurata) after administration through medicated feed, Food Control (2017),
The apparent digestibility coefficients (ADCs) of differently processed okara meals were assessed... more The apparent digestibility coefficients (ADCs) of differently processed okara meals were assessed in Nile tilapia diets: dried okara not autoclaved (FOK), dried okara autoclaved (AOK), okara hydrolyzed with Alcalase (ALOK) or Cynara cardunculus proteases (CYOK), and hydrolyzed okara fermented with lactic bacteria: Lactobacillus rhamnosus R11 (CYR11OK) or Bifidobacterium animalis ssp. lactis Bb12 (CYB12OK). Okara processing significantly affected nutrient digestibility: dry matter ADC was highest in CYR11OK (80%) and lowest in FOK (40%). The lowest protein digestibility was observed in CYR11OK (72%), and the highest in AOK (97%) and CYOK (91%), evidencing the effectiveness of the autoclave and the use of C. cardunculus proteases to increase okara protein bioavailability. The inclusion of up to 20% of AOK or CYOK did not affect fish growth, nutrient utilization, or whole body composition of Nile tilapia. The flesh quality (color, pH, water activity, cohesiveness, elasticity and resili...
Abstract Glycerol is an inexpensive source of dietary energy, although its inclusion in compound ... more Abstract Glycerol is an inexpensive source of dietary energy, although its inclusion in compound feeds has been barely investigated in fish. The effects of dietary refined glycerol inclusion on growth performance, nitrogen and energy balance, as well as its digestibility and intestinal digestive enzyme activities was studied in rainbow trout. Fish (initial BW 20.2 ± 0.1 g, mean ± SE) were divided into nine tanks (1.66 kg m−3), each one assigned to the experimental diets, in triplicates. Fish were fed twice a day to apparent satiation for 60 days three diets including 0, 25, or 50 g kg−1 of refined glycerol (G0, G25, and G50, respectively) with similar digestible protein to energy ratios (22 mg kJ−1). A digestibility trial was conducted in parallel to the growth trial by using a Choubert System to collect feces, in triplicates. Refined glycerol was well digested (ADCglycerol > 99.7%) when included up to 50 g kg−1. Specific growth rate (SGR) decreased as glycerol inclusion levels increased in the diet (P = 0.029). Feed intake was enhanced with increasing dietary inclusion levels of glycerol (P = 0.013). The feed efficiency decreased linearly as the glycerol inclusion levels increased in the diet, reflected in a higher FCR ratio, particularly in the G50 group compared to the G0 or G25 groups (1.04 ± 0.02, 0.90 ± 0.02 and 0.91 ± 0.02, respectively). Total ammonia nitrogen excretion rate (TANER) was measured in trout at the end of the growth trial, displaying increased values with higher dietary glycerol inclusion levels (P
Abstract Concerns about antibiotic use led to stricter legislations and overall better practices ... more Abstract Concerns about antibiotic use led to stricter legislations and overall better practices in aquaculture production. However, depletion time periods in tissues vary greatly with different antimicrobials, fish species, or experimental setup. In the present work, five drugs (sulfadiazine (SDZ), trimethoprim (TRI), flumequine (FLU), oxolinic acid (OXO), and oxytetracycline (OTC)) were incorporated into medicated feed, and their retention in European seabass muscle tissues assessed. Juveniles were placed in 300 L tanks at 18 °C and were manually fed with medicated feeds for a 7 day period (two concentrations per antimicrobial, ranging from 6 to 220 mg kg−1, which were based on previous studies on the occurrence of these antimicrobials). Residues were analyzed through a multi-class quantification method (UHPLC-MS/MS). Data on residues concentration through time followed a one-compartment model, with TRI concentrations above the established Maximum Residue Level (MRL) throughout the experiment. Similarly, OTC concentrations at the highest dose were also above 100 μg kg−1 up to 14 days after the medication period. Results obtained for TRI may indicate the presence of a dose dependency for this antimicrobial. FLU concentrations in muscle samples were the lowest through time (Cday7 of 279.70 and 386.63 μg kg−1, for prophylactic and therapeutic treatments, respectively). Half-life values of 14.37, 10.87, 5.36, 7.20, and 27.22 h (prophylactic treatment), and 20.95, 8.41, 5.61, 11.22, and 17.99 h (therapeutic treatment), were determined for SDZ, TRI, FLU, OXO, and OTC, respectively. Withdrawal times of 0, 2, and 5 days were determined for FLU, OXO, and SDZ, but sampling times for OTC and TRI should be longer, since antimicrobial concentrations were above the MRL 14 days after the end of the feeding period with medicated feed. Therefore, special attention should be given since they are the most used antibiotics in aquaculture and European seabass plays a major part in human nutrition in the Mediterranean region.
Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This stu... more Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficien...
The impact of deoxynivalenol (DON) on rainbow trout, Oncorhynchus mykiss, is mainly characterised... more The impact of deoxynivalenol (DON) on rainbow trout, Oncorhynchus mykiss, is mainly characterised by impaired growth performance and reduced feed intake, usually with the total absence of any visible clinical signs. Despite the high concentrations of DON in the present study (up to 11,412 ± 1,141 µg kg -1 ), no clinical signs (except anorexia at the higher DON dosage) were observed, which confirms the difficulties of diagnosing DON ingestion. Compared to the control group, the proteolytic enzyme activities (pepsin, trypsin and chymotrypsin) in trout were altered by DON ingestion. However, it was not clear if the observed impact on digestive enzymes was due to the direct action of DON, or a consequence of the lower feed intake determined for DON-treated animals. The impact of DON on the abundance of specific measured mRNA transcripts was unexpected with higher expression levels for insulin-like growth factors, igf1 and igf2, which are directly related to elevated insulin levels in plasma. This can also in part be influenced by the trypsin activity and by npy, given its higher mRNA expression levels. The apparent digestibility of dry matter, protein and energy was not affected by dietary levels of DON, however, nutrient retention, protein, fat and energy retention were significantly affected in animals fed DON. Adenylate cyclaseactivating polypeptide (PACAP) expression seems to play an important role in controlling feed intake in DON fed trout. In the present study, we have shown for the first time that DON is metabolized to DON-3-sulfate in trout. DON-3-sulfate is much less toxic than DON, which helps to explain the lack of clinical signs in fish fed DON. Being a novel metabolite identified in trout makes it a potential biomarker of DON exposure. Suppression of appetite due to DON contamination in feeds might be a defense mechanism in order to decrease the exposure of the animal to DON, therefore reducing the potential negative impacts of DON.
Probiotic administration can be a nutritional strategy to improve the immune response and growth ... more Probiotic administration can be a nutritional strategy to improve the immune response and growth performance of fish. The current study aimed to evaluate the effects of a probiotic blend (Bacillus sp., Pediococcus sp., Enterococcus sp., Lactobacillus sp.) as a dietary supplement on growth performance, feed utilization, innate immune and oxidative stress responses and intestinal morphology in juvenile Nile tilapia (Oreochromis niloticus). The probiotic was incorporated into a basal diet at three concentrations: 0 g/kg (A0: control), 3 g/kg (A1: 1.0×106 colony forming unit (CFU)/g) and 6 g/kg (A2: 2.3×106 CFU/g diet). After 8 weeks of probiotic feeding, weight and specific growth rate where significantly higher in fish-fed A1 diet than in fish-fed A0. Alternative complement in plasma was significantly enhanced in fish-fed A2 when compared with A0. The hepatic antioxidant indicators were not affected by probiotic supplementation. Villi height and goblet cell counts increased significan...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
A great deal of attention has been paid to the replacement of the high levels of fishmeal present... more A great deal of attention has been paid to the replacement of the high levels of fishmeal present in commercial diets by alternative animal and vegetable protein sources. There are some contradictory data on the effects of partial or total replacement of dietary fishmeal especially regarding vegetable protein sources. The effect of technological treatments applied to the vegetable materials and the quality of the control diets are the reasons for these contradictory results. A ten week growth trial was conducted to study the effect of partial or total replacement of fishmeal by plant proteins in diets for rainbow trout. For this purpose, four practical diets were formulated: a fishmeal-based control diet, which included a brown fishmeal as the only protein source (diet C1); another diet where 5% of the brown fishmeal protein was replaced by a fishmeal protein concentrate (CPSP; diet C2); and two other diets where 50% (diet C50) and 100% (diet C100) of the fish meal protein was replaced by plant protein sources (soybean meal, fullfat soybean and corn gluten meal). The results of the growth trial showed that 50% of the fishmeal protein can be replaced by vegetable protein sources with no adverse effects on growth and feed utilization when diet C1 was used as control. However, using diet C2 as control, weight gains of trout fed the other diets were all significantly lower. Nitrogen and phosphorus balances were also estimated and results are discussed regarding the effect of diet quality on environmental impact.
Dietary conjugated linoleic acids (CLA) have been shown to alter growth rates and reduce body fat... more Dietary conjugated linoleic acids (CLA) have been shown to alter growth rates and reduce body fat storage by altering the activity of key enzymes involved in lipid metabolism, in several species, but have not been evaluated in rainbow trout. A 12-week growth trial was conducted with rainbow trout juveniles, having an initial weight of 5.3±0.03 g (mean±S.D.). Fish were fed
... Pongmaneerat, J. and Watanabe, T., 1993. Effect of extrusion processing on the utilization of... more ... Pongmaneerat, J. and Watanabe, T., 1993. Effect of extrusion processing on the utilization of soybean meal diets for rainbow trout. Nippon Suisan Gakkaishi, 59: 14071414. ... Nutritional evaluation of brown fish meals as a protein source in diets for rainbow trout. Bull. ...
This manuscript describes and evaluates the FEEDNETICS model, a detailed mechanistic nutrient-bas... more This manuscript describes and evaluates the FEEDNETICS model, a detailed mechanistic nutrient-based model that has been developed to be used as a data interpretation and decision-support tool by fish farmers, aquafeed producers, aquaculture consultants and researchers. The modelling framework comprises two main components: (i) fish model, that simulates at the individual level the fish growth, composition, and nutrient utilization, following basic physical principles and prior information on the organization and control of biochemical/metabolic processes; and (ii) farm model, that upscales all information to the population level. The model was calibrated and validated for five commercially relevant farmed fish species, i.e., gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Nile tilapia (Oreochromis niloticus), using data sets covering a wide range of rearing and feeding conditions. The...
Two trials were carried out to evaluate the apparent digestibility coefficients (ADCs) of dry mat... more Two trials were carried out to evaluate the apparent digestibility coefficients (ADCs) of dry matter (DM), crude protein (CP), lipids, starch and gross energy (GE) of six European varieties of grain legumes, namely chickpea-type Kabuli (CHK), chickpeatype Desi (CHD), field pea (FP), faba bean (FB), white lupin (WL) and chickling vetch (CV), in rainbow trout and Nile tilapia juveniles. The ADCs were measured using a reference diet and six experimental diets (700 g/kg of the reference diet and 300 g/kg of each raw grain legume) containing 10 g/kg chromic oxide as inert marker. Additionally, grain legumes were analysed for the organic acids profile. In rainbow trout, FP presented the highest ADCs of DM, CP and GE, whereas chickpeas and FB had the lowest DM, GE and starch ADC values. In Nile tilapia, the lowest values of nutrients (except starch) and energy ADCs were found for FP and CV. Nutrients and energy of chickpeas, WL and FB were better digested by tilapia, whereas FP was better digested by trout. Overall results reveal raw grain legumes as promising feed sources for both fish species.
The present study evaluated the effects of the inclusion of three seaweeds, Gracilaria vermiculop... more The present study evaluated the effects of the inclusion of three seaweeds, Gracilaria vermiculophylla (GRA), Porphyra dioica (POR), and Ulva spp. (ULV), as dietary ingredients for Nile tilapia (Oreochromis niloticus) juveniles, on the growth performance, body composition, and gut histology. Three experimental diets (GRA, POR, and ULV) were formulated to replace 10 % of whole diet by each of the three seaweeds. A control diet (CTRL) was used, without inclusion of any seaweed. Diets were fed to triplicate groups of 25 Nile tilapia juveniles, with an average body weight (ABW) of 12.1 g, in an 84-day trial. At the end of the trial, growth performance was significantly reduced (P<0.05) in fish fed the GRA diet, whereas the feed conversion ratio increased significantly in those fish. None of the treatments caused adverse effects on body composition. The inclusion of the three seaweeds in the diet led to evident changes in the fish digestive system morphology with significant reduction of villi length on GRA diet. The results obtained in this study suggest the usefulness of P. dioica and Ulva spp. to partially replace fishmeal in practical diets for tilapia juveniles up to 10 %, as no negative consequences on growth performance or body composition were observed. However, the inclusion of 10 % G. vermiculophylla seems to have a negative effect in diet palatability, reducing fish feed intake and growth performance. Keywords Nile tilapia. Alternative feed ingredients. Seaweeds. Gracilaria vermiculophylla. Porphyra dioica. Ulva spp.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
An ultrasound and image analysis non-invasive and non-destructive method for predicting skin fat,... more An ultrasound and image analysis non-invasive and non-destructive method for predicting skin fat, filet muscle fat, and whole body fat depots in live Senegalese sole (Sole senegalensis) was evaluated. The experiment was conducted with Senegalese sole of commercial market size (n = 46, mean weight 278 ± 78 g). The fishes under a mild anesthesia were placed in a rectangular metallic container and were scanned with a real time ultrasound (RTU) scanner equipped with a linear array transducer of 7.5 MHz. For all fish, four cross-sectional RTU images of the dorsal anterior filet was obtained. The RTU images were analyzed using ImageJ software to determine the fish subcutaneous fat (SF) at each section. After this, fish were killed, and the right dorsal filet of each fish was dissected in muscle and skin. These two components and the remaining of the fish were ground and homogenized for chemical analysis. The skin fat, filet muscle fat and whole body chemical fat contents were obtained. The relationships between the SF obtained from image analysis and skin fat, filet muscle fat and whole body fat were computed using simple regression and partial least squares regression (PLSR). The skin and filet muscle had lower fat than the whole body (1.5 and 4.5 versus 6.6%, respectively). Filet muscle presents the lowest fat depot (1.5%). The SF obtained from RTU and image analysis shows a mean value between 2.8 and 3.5%. All fat depots were significantly correlated with SF obtained by RTU and image analysis, with R 2 values ranging from 0.707 to 0.851 for skin fat, 0.725 to 0.802 for filet muscle fat and 0.664 to 0.760 for whole body fat. The PLSR models explained accurately the skin fat (R 2 = 0.875 and RMSEP = 0.506), filet muscle fat (R 2 = 0.800 and RSMEP = 0.117) and whole body fat (R 2 = 0.785 and RSMEP = 0.586). Our results suggest that RTU and image analysis is a practical and feasible non-invasive and non-destructive technique for in vivo fat depots prediction in Senegalese sole fish. Statement of relevance: In aquaculture, the knowledge of the body composition in live fish, particularly fat content, is important for feeding, reproduction and genetics programs. However, all those programs depend critically on quick, accurate, and above all, non-invasive methods to predict body composition in live fish. Traditionally fish body composition was determined by comparative slaughtering followed by chemical analysis. Comprehensive studies using image techniques such as real time ultrasonography (RTU) show the ability of this technique to predict fish body composition traits. This technique is non-invasive and non-destructive and therefore is very useful for use in vivo for fish body composition examinations. Our present work investigated the ability of RTU and image analysis to predict in vivo fat composition of Solea senegalensis. Through this work monitoring fat variations with time and the possibility of repeated measurements on the same individuals and on a high number of live fish throughout the life-cycle is possible. Therefore our present study has close relevance to aquaculture particularly to nutrition status of farmed fishes.
Evaluation of antimicrobials residues in farmed gilthead seabream (Sparus aurata) after administr... more Evaluation of antimicrobials residues in farmed gilthead seabream (Sparus aurata) after administration through medicated feed, Food Control (2017),
The apparent digestibility coefficients (ADCs) of differently processed okara meals were assessed... more The apparent digestibility coefficients (ADCs) of differently processed okara meals were assessed in Nile tilapia diets: dried okara not autoclaved (FOK), dried okara autoclaved (AOK), okara hydrolyzed with Alcalase (ALOK) or Cynara cardunculus proteases (CYOK), and hydrolyzed okara fermented with lactic bacteria: Lactobacillus rhamnosus R11 (CYR11OK) or Bifidobacterium animalis ssp. lactis Bb12 (CYB12OK). Okara processing significantly affected nutrient digestibility: dry matter ADC was highest in CYR11OK (80%) and lowest in FOK (40%). The lowest protein digestibility was observed in CYR11OK (72%), and the highest in AOK (97%) and CYOK (91%), evidencing the effectiveness of the autoclave and the use of C. cardunculus proteases to increase okara protein bioavailability. The inclusion of up to 20% of AOK or CYOK did not affect fish growth, nutrient utilization, or whole body composition of Nile tilapia. The flesh quality (color, pH, water activity, cohesiveness, elasticity and resili...
Abstract Glycerol is an inexpensive source of dietary energy, although its inclusion in compound ... more Abstract Glycerol is an inexpensive source of dietary energy, although its inclusion in compound feeds has been barely investigated in fish. The effects of dietary refined glycerol inclusion on growth performance, nitrogen and energy balance, as well as its digestibility and intestinal digestive enzyme activities was studied in rainbow trout. Fish (initial BW 20.2 ± 0.1 g, mean ± SE) were divided into nine tanks (1.66 kg m−3), each one assigned to the experimental diets, in triplicates. Fish were fed twice a day to apparent satiation for 60 days three diets including 0, 25, or 50 g kg−1 of refined glycerol (G0, G25, and G50, respectively) with similar digestible protein to energy ratios (22 mg kJ−1). A digestibility trial was conducted in parallel to the growth trial by using a Choubert System to collect feces, in triplicates. Refined glycerol was well digested (ADCglycerol > 99.7%) when included up to 50 g kg−1. Specific growth rate (SGR) decreased as glycerol inclusion levels increased in the diet (P = 0.029). Feed intake was enhanced with increasing dietary inclusion levels of glycerol (P = 0.013). The feed efficiency decreased linearly as the glycerol inclusion levels increased in the diet, reflected in a higher FCR ratio, particularly in the G50 group compared to the G0 or G25 groups (1.04 ± 0.02, 0.90 ± 0.02 and 0.91 ± 0.02, respectively). Total ammonia nitrogen excretion rate (TANER) was measured in trout at the end of the growth trial, displaying increased values with higher dietary glycerol inclusion levels (P
Abstract Concerns about antibiotic use led to stricter legislations and overall better practices ... more Abstract Concerns about antibiotic use led to stricter legislations and overall better practices in aquaculture production. However, depletion time periods in tissues vary greatly with different antimicrobials, fish species, or experimental setup. In the present work, five drugs (sulfadiazine (SDZ), trimethoprim (TRI), flumequine (FLU), oxolinic acid (OXO), and oxytetracycline (OTC)) were incorporated into medicated feed, and their retention in European seabass muscle tissues assessed. Juveniles were placed in 300 L tanks at 18 °C and were manually fed with medicated feeds for a 7 day period (two concentrations per antimicrobial, ranging from 6 to 220 mg kg−1, which were based on previous studies on the occurrence of these antimicrobials). Residues were analyzed through a multi-class quantification method (UHPLC-MS/MS). Data on residues concentration through time followed a one-compartment model, with TRI concentrations above the established Maximum Residue Level (MRL) throughout the experiment. Similarly, OTC concentrations at the highest dose were also above 100 μg kg−1 up to 14 days after the medication period. Results obtained for TRI may indicate the presence of a dose dependency for this antimicrobial. FLU concentrations in muscle samples were the lowest through time (Cday7 of 279.70 and 386.63 μg kg−1, for prophylactic and therapeutic treatments, respectively). Half-life values of 14.37, 10.87, 5.36, 7.20, and 27.22 h (prophylactic treatment), and 20.95, 8.41, 5.61, 11.22, and 17.99 h (therapeutic treatment), were determined for SDZ, TRI, FLU, OXO, and OTC, respectively. Withdrawal times of 0, 2, and 5 days were determined for FLU, OXO, and SDZ, but sampling times for OTC and TRI should be longer, since antimicrobial concentrations were above the MRL 14 days after the end of the feeding period with medicated feed. Therefore, special attention should be given since they are the most used antibiotics in aquaculture and European seabass plays a major part in human nutrition in the Mediterranean region.
Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This stu... more Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficien...
The impact of deoxynivalenol (DON) on rainbow trout, Oncorhynchus mykiss, is mainly characterised... more The impact of deoxynivalenol (DON) on rainbow trout, Oncorhynchus mykiss, is mainly characterised by impaired growth performance and reduced feed intake, usually with the total absence of any visible clinical signs. Despite the high concentrations of DON in the present study (up to 11,412 ± 1,141 µg kg -1 ), no clinical signs (except anorexia at the higher DON dosage) were observed, which confirms the difficulties of diagnosing DON ingestion. Compared to the control group, the proteolytic enzyme activities (pepsin, trypsin and chymotrypsin) in trout were altered by DON ingestion. However, it was not clear if the observed impact on digestive enzymes was due to the direct action of DON, or a consequence of the lower feed intake determined for DON-treated animals. The impact of DON on the abundance of specific measured mRNA transcripts was unexpected with higher expression levels for insulin-like growth factors, igf1 and igf2, which are directly related to elevated insulin levels in plasma. This can also in part be influenced by the trypsin activity and by npy, given its higher mRNA expression levels. The apparent digestibility of dry matter, protein and energy was not affected by dietary levels of DON, however, nutrient retention, protein, fat and energy retention were significantly affected in animals fed DON. Adenylate cyclaseactivating polypeptide (PACAP) expression seems to play an important role in controlling feed intake in DON fed trout. In the present study, we have shown for the first time that DON is metabolized to DON-3-sulfate in trout. DON-3-sulfate is much less toxic than DON, which helps to explain the lack of clinical signs in fish fed DON. Being a novel metabolite identified in trout makes it a potential biomarker of DON exposure. Suppression of appetite due to DON contamination in feeds might be a defense mechanism in order to decrease the exposure of the animal to DON, therefore reducing the potential negative impacts of DON.
Probiotic administration can be a nutritional strategy to improve the immune response and growth ... more Probiotic administration can be a nutritional strategy to improve the immune response and growth performance of fish. The current study aimed to evaluate the effects of a probiotic blend (Bacillus sp., Pediococcus sp., Enterococcus sp., Lactobacillus sp.) as a dietary supplement on growth performance, feed utilization, innate immune and oxidative stress responses and intestinal morphology in juvenile Nile tilapia (Oreochromis niloticus). The probiotic was incorporated into a basal diet at three concentrations: 0 g/kg (A0: control), 3 g/kg (A1: 1.0×106 colony forming unit (CFU)/g) and 6 g/kg (A2: 2.3×106 CFU/g diet). After 8 weeks of probiotic feeding, weight and specific growth rate where significantly higher in fish-fed A1 diet than in fish-fed A0. Alternative complement in plasma was significantly enhanced in fish-fed A2 when compared with A0. The hepatic antioxidant indicators were not affected by probiotic supplementation. Villi height and goblet cell counts increased significan...
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