Substitution Of Dietary Fish Meal Research Articles

Effects of Partial and Full Dietary Substitution of Fish Meal and Soybean Meal by Sunflower Meal on Growth Performance, Feed Consumption, Body Indices, Serum Chemistry and Intestine Morphology of Oreochromis niloticus

A 03-months feeding experiment was designed to study the effects of partial and full dietary substitution of fish meal and soybean meal with sunflower meal (SFM) on growth performance, feed consumption, body indices, serum chemistry and intestine morphology of Oreochromis niloticus. Five isonitrogenous and isocaloric dietary treatments: T1, T2, T3, T4 and T5 were prepared by supplementing SFM at 0%, 25%, 50%, 75% and 100% respectively and fed to fish (4 ± 0.07 g) in triplicates. The growth performance and feed consumption in O. niloticus was significantly (p < 0.05) improved and body indices was significantly reduced in groups fed with T1 (control), T2 and T3 however, survival rate was remained unaffected among all dietary treatments. Significantly increased whole-body protein, serum total protein and albumin content was found in groups fed with T1 (control), T2 and T3, compared to T4 and T5 groups whereas, whole-body lipid content was significantly elevated in T5 group. In contrast, serum glutamic-pyruvic transaminase (SGPT) and glutamic-oxalacetic transaminase (SGOT) activity was significantly elevated in groups fed with T4 and T5. Additionally, serum triglycerides and cholesterol level were significantly increased in group T1 compared to other groups however, glucose and creatinine were not affected by dietary treatments. Uran`s pooled score for intestinal histology was significantly increased in SFM supplemented treatments as compared to control group. In conclusion, replacement of SBM with SFM up to 50% is possible without negative impacts on growth performance and health status of O. niloticus.

Growth Performance, Feed Utilization, Gut Integrity, and Economic Revenue of Grey Mullet, Mugil cephalus, Fed an Increasing Level of Dried Zooplankton Biomass Meal as Fishmeal Substitutions

Fishmeal is the most expensive feedstuff in the aquafeed and one of the most environmentally limiting factor of aquaculture development. Therefore, the search for alternative protein sources is a continuous process. The present feeding trial was conducted to evaluate the effects of replacing fishmeal with zooplankton biomass meal (ZBM) on the growth performance, nutrient utilization, intestine, and liver histological changes of grey mullet, Mugil cephalus (initial weight of 0.10 ± 0.01 g). Five isoproteic (35% crude protein) and isolipidic (8% crude lipid) diets were formulated as the control diet (Z0) and the other four diets (Z25, Z50, Z75, and Z100), where 25%, 50%, 75%, and 100% of fishmeal was replaced by ZBM, respectively. After 60 days of feeding, the final weight, weight gain, and daily growth index of the grey mullet fed the Z100 diet were higher than those fed the control diet (p < 0.05). In addition, the better values of feed conversion ratio, protein efficiency ratio and lipid efficiency ratio were recorded in the fish fed with the Z100 diet. Additionally, the intestinal villus length, crypts depth, and muscle thickness were significantly improved with ZBM inclusion (p < 0.05). Meanwhile, there were no histopathological changes observed on the liver when compared with the control group. From the economic point of view, dietary substitution of fishmeal by ZBM (Z100) reduced the cost of diet formulation by 18% and the price per kg weight gain by about 40%. Overall, according to the findings of this study, substituting fishmeal with ZBM up to 100% could improve growth performance, feed utilization, gut health status, and profit ability of rearing M. cephalus juveniles.

Dietary substitution of fish meal by meat meal: Effects on juvenile olive flounder ( Paralichthys olivaceus ) growth performance, feed utilization, haematology, biochemical profile and disease resistance against Streptococcus iniae

This study investigated dietary substitution effect of fish meal (FM) with meat meal (MM) on growth, feed utilization, chemical composition, and amino and lipid acid profiles of juvenile olive flounder (Paralichthys olivaceus) and challenge test against Streptococcus iniae. A total of 525 fish were distributed into 21 flow-through tanks. 650 g/kg FM was included in the control (Con) diet. 100, 200, 400, 600, 800 and 1000 g/kg of FM were substituted with MM, referred to as the MM100, MM200, MM400, MM600, MM800 and MM1000 diets, respectively. Fish were daily hand-fed to apparent satiation for 8 weeks. The highest weight gain, specific growth rate and feed consumption were obtained in fish fed the MM200 diet. Weight gain, specific growth rate, feed consumption, protein efficiency ratio, protein retention and condition factor of fish fed the MM100 and MM400 diets were not significantly (p > .05) different from those of fish fed the Con diet. Plasma chemistry and non-specific immune responses of fish were not significantly (p > .05) affected by the experimental diets. No significant (p > .9) difference in survival of fish after S. iniae infection was observed during the 8-day postobservation. In conclusion, FM up to 400 g/kg could be replaced with MM without deterioration of growth, feed consumption, feed utilization, non-specific immune responses and disease resistance of fish against S. iniae.

Effects of partial substitution of dietary fishmeal by fermented soybean meal on growth, amino acid and protein metabolism of juvenileNibea diacanthus

Effects of partial substitution of dietary fishmeal by fermented soybean meal on growth, amino acid and protein metabolism of juvenile<i>Nibea diacanthus</i>

Valorisation and enhanced sustainability of Senegalese sole (Solea senegalensis) aquaculture by dietary use of ditch shrimp (Palaemonetes varians) meal

The European Blue Growth Strategy requires innovative proposals contributing to sustainable development of the aquaculture activity. Within this context, ditch shrimp (Palaemonetes varians) meal obtained from extensively managed aquaculture wetlands was assessed as a potential source to substitute dietary fishmeal (FM) in compound diets for Senegalese sole (Solea senegalensis) juveniles. Estuarine ditch shrimp biomass from an integrated aquaculture system was converted into a meal that contained 61.9% protein and 9.2% lipid on a dry matter (DM) basis. The n-3 highly unsaturated fatty acids (HUFA) constituted the main fraction of the polyunsaturated fatty acids (PUFA). Three isonitrogenous (55% DM), isolipidic (12% DM) and isoenergetic (17 kJ g−1 DM) diets containing three substitution levels of FM by ditch shrimp meal (SM) were elaborated: 100% FM + 0% SM (SM0); 50% FM + 50% SM (SM50) and 0% FM + 100% SM (SM100). The experimental diets were tested on duplicate groups of sole juveniles (~4 g body weight) in an experiment that lasted 63 days. The substitution of dietary FM with SM did not influence growth and feed intake of the reared fish. Juveniles fed SM100 significantly decreased their muscle and skin lipid depositions in comparison with soles fed SM0. Moreover, muscle lipid analyses showed arachidonic acid (ARA) enrichment caused by the SM dietary use and a major presence of the n-3 over n-6 PUFA. Overall results demonstrate that dietary incorporation of P. varians meal in compound diets for Senegalese sole would add nutritional value to the harvested product with no impact on growth performance of reared fish. The dietary use of a low trophic level marine resource is an innovative practice that may contribute to a further sustainable development of aquaculture of carnivorous fish species.

Growth and Survival Evaluation of Oreochromis Sp fed Hermetia illucens Larva and Manihot esculenta leaves Meal

This study was conducted to compare the effects of dietary substitution of fish meal (FM) with black soldier fly (Hermetia illucens) larvae meal (BSFM) and Manihot esculenta leaves meal (MEM) on the growth and feed efficiency of Oreochromis sp. Four concentrations viz: P1 (25%): 50g BSFM and 25g MEM, P2 (50%): 100g BSFM and 50g MEM, P3 (75%): 150g BSFM and 75g MEM, P4 (100%): 200g BSFM and 100g MEM were prepared and tested against control without FM replacement. Each diet was fed to three replicates groups of fish at a rate of 5% of body weight two times per day for 30 days. At the end of the trial, growth parameters, Feed conversion rate (FCR), and feed efficiency (FE) were evaluated. The results showed that fish fed dietary substitution of FM with combination ratio of BSFM and MEM higher than 50% significantly improved all growth parameters, FCR and FE. It is therefore suggested that the partial (higher than 50%) or total replacement of fish meal with combination of BSFM and MEM in the diet of Oreochromis sp can be used as fish meal substitution to obtain better growth and feed efficiency.

Black soldier fly larvae meal can replace fish meal in diets of sea-water phase Atlantic salmon (Salmo salar)

A feeding trial was conducted to test the growth potential, nutritional utilization, liver health and fillet sensory parameters of sea-water Atlantic salmon (Salmo salar L.) fed diets with increasing substitution of fish meal with insect meal. The insect meal was produced from black soldier fly larvae (Hermetia illucens, L.). Triplicate sea-cages of salmon were fed one of four isonitrogenous and isolipidic diets for 16 weeks. The control diet (IM0) contained 100 g kg−1 fish meal, which was replaced up to 100% with insect meal (33% (IM33), 66% (IM66) and 100% (IM100)), corresponding to dietary insect meal inclusion levels at 50 g kg−1, 100 g kg−1 and 150 g kg−1, respectively. Replacing the dietary fish meal with insect meal did not affect the apparent digestibility coefficients (ADC) of protein, lipid, amino acids and fatty acids, or the digestive enzyme activities. Feed intake, daily growth increase, and feed conversion ratio were also unaffected by the inclusion of insect meal in the diets. Whole body protein, lipid and amino acid composition were not affected by dietary substitution of fish meal with insect meal, while the whole body fatty acid composition generally reflected that of the diets. Liver lipid accumulation was not affected by replacing the fishmeal with insect meal, as assessed by both histological examinations and chemical analyses. The sensory testing of the fillet revealed only small changes in the fillet sensory quality. In general, this study showed that a total replacement of fish meal with black soldier fly larvae meal in the diets of sea-water Atlantic salmon was possible without negative effects on growth performance, feed utilization, nutrient digestibility, liver traits or the sensory qualities of the fillet.

Substitution of dietary fishmeal by soybean meal with inosine administration influences growth, digestibility, immunity, stress resistance and gut morphology of juvenile amberjack Seriola dumerili

We determined the dietary inosine effects in gradually replaced fishmeal (FM) with soybean meal (SBM) protein-based diets on growth, digestibility, immunity, stress resistance and gut morphology of juvenile amberjack. Seven experimental diets were formulated to be nearly isonitrogenous (48% crude protein) where diet 1 (D1) was FM based control diet. Diet 2 to 7 were formulated by replacing 25, 50 and 75% of FM protein with SBM and each replacement level was supplemented with or without inosine at 0.6% for diet groups D2(FM25INO), D3(FM25), D4 (FM50INO), D5(FM50), D6(FM75INO) and D7(FM75), respectively. Triplicate groups of fish (24.9 g) were randomly stocked in 200 L polycarbonate tanks at a rate of 24 fish per tank and fed to satiation twice daily for 56 days. After the feeding trial, final weight, specific growth rate, and weight gain were not significantly different among the treatments with that of the 50% replacement containing inosine. Without inosine-supplemented 50% replaced group and with or without inosine-supplemented 75% replaced group showed reduced growth and feed utilization performances. The apparent digestibility coefficients of dry matter, protein and lipid were significantly higher in control and other replacement groups with inosine supplementation. In the case of oxidative stress parameters, fish fed inosine-supplemented diets showed the best condition. Stress resistance against low salinity exposure (LT50), significantly increased with inosine supplementation and was highest in inosine-supplemented 50% replacement diet group. Total serum protein (TSP), alternative complement pathways (ACH50), lysozyme activity (LA), bactericidal activity (BA) and peroxidase activity (PA) tended to be higher in inosine-supplemented groups compared to the non-supplemented groups. Simultaneously, enterocyte height, fold height, and microvillus height of the anterior and posterior enteric sections increased significantly with the inosine supplementation. Results of the study indicated that at least half of the fishmeal could be replaced with soybean meal and supplementation of inosine in the diets of juvenile amberjack. Moreover, inosine administration in 50 to 75% FM replacement groups could be helpful to improve the digestibility, immune responses, stress resistance, and intestinal health condition of fish.

Dietary substitution of fishmeal by alternative protein with guanosine monophosphate supplementation influences growth, digestibility, blood chemistry profile, immunity, and stress resistance of red sea bream, Pagrus major.

We determined the effects of complete fishmeal (FM) replacement by alternative protein (soy protein concentrate, SPC) with guanosine monophosphate (GMP) supplementation on growth, digestibility, immunity, blood chemistry profile, and stress resistance of juvenile red sea bream, Pagrus major. FM protein of a FM-based control diet (FM0) was replaced with 33.3 (FM33.3), 66.6 (FM66.7), and 100% (FM100) by SPC protein, and each replacement group was supplemented with 0.4% GMP to formulate four experimental diets. Each diet was randomly allocated to triplicate groups of fish (4.8g) for 56days. Results demonstrated that fish fed diet group FM33.3 had the significantly highest final weight, weight gain-specific growth rate, and feed intake. Meanwhile, in comparison to control, growth performance and feed utilization did not significantly differ with 66.7% FM replacement by SPC with GMP supplementation. Apparent digestibility coefficient of protein and lipid also followed a similar trend. All growth, feed utilization, and digestibility parameters were significantly lower in FM100 diet group. Blood urea nitrogen (BUN) and triglycerides (TG) increased (P<0.05) with increasing FM replacement level by SPC. Interestingly, total cholesterol level reduces with the increasing level of FM replacement by SPC with GMP supplementation. Fish fed FM0 diet group showed the best condition of both oxidative and freshwater stress resistance. Meanwhile, FM33.3 and FM66.7 diet groups showed acceptable conditions. Innate immune responses enhanced with the increasing FM replacement level by SPC with GMP supplementation. In conclusion, FM could be replaced ≤66.7% by SPC with GMP supplementation in diets for red sea bream without any adverse effects on fish performances.

Partial or total replacement of fish meal by solid state fermented soybean meal with Saccharomyces cerevisiae in diets for Indian prawn shrimp, Fenneropenaeus indicus, Postlarvae

A grow-out experiment was designed to investigate the effect of substitution of dietary fish meal (FM) with solid state fermented soybean meal (SSF-SBM) with yeast (Saccharomyces cerevisiae) on growth performance, feed utilization and palatability of white shrimp, Fenneropenaeus indicus postlarvae (PL) for 90 days. A total of 225 F. indicus PL with an average weight of 0.02±0.018g were equally distributed over 15 glass aquaria (15 PL, 80L each triplicate per treatment). Five isonitrogenous (400g/kg crude protein and isocaloric 19.5MJ/kg gross energy) were formulated. The control diet (FS0) contained fish meal (FM) as the main protein source. In the other diets, FM was partially replaced (on a protein basis) with 25% (FS25), 50% (FS50), 75% (FS75) or 100% (FS100) solid state fermented soybean meal (SSF-SBM). The results showed that survival (SR), final body weight (FBW), weight gain (WG) and specific growth rate (SGR) were significantly decreased with the increasing dietary level of SSF-SBM. The results indicate that SSF-SBM with yeast, S. cerevisiae, is an acceptable alternative plant protein source that can replace up to 50% of dietary FM protein in diets of Indian white shrimps, F. indicus PL which yields similar growth and production, and is as cost effective, as the control diet.

Effect of substitution of dietary fish meal by soybean meal on different sizes of gibel carp (Carassius auratus gibelio): digestive enzyme gene expressions and activities, and intestinal and hepatic histology

A 7-week growth trial was conducted to evaluate the effects of dietary soybean meal (SBM) on digestive enzyme activity of intestinal mucosa, mRNA levels of digestive enzymes in hepatopancreas, and the mid-intestinal and hepatopancreas histology of gibel carp CAS III (Carassius auratus gibelio). Four different growth phases of gibel carp (initial body weight: fry, 0.8 g; juvenile, 5.0 g; 1-year-old, 62.7 g; and broodstock, 135.6 g) were tested. Seven isonitrogenous and iso-energetic diets were formulated to contain different SBM replacement levels (0%, 20%, 40%, 60%, 80% and 100% of dietary fish meal protein), and another diet (SBMAA) contained all SBM protein and supplied crystalline amino acids. The results showed that the activities of mid-intestine trypsin, α-amylase and gamma glutamyl transpeptidase reduced with increased dietary SBM, while the chymotrypsin activity increased first and then decreased. The ultrastructures of intestinal epithelial cells and hepatopancreas cells in fry and broodstock fish were distinctly affected by 200 g kg-1 dietary SBM. Supplementation of dietary amino acid to the highest replacement groups was not sufficient to improve digestive and absorptive capacities and growth performance. Gibel carp may be adapted to dietary SBM through increase in gene expression of hepatopancreas digestive enzymes and has potential to utilize proceeded SBM as feedstuffs.

Effects of substituting fish meal with poultry by-product meal in broiler diets on blood urea and uric acid concentrations and nitrogen content of litter

This study was carried out to investigate the effects of dietary substitution of fish meal (FM) with poultry by-product meal (PBM) at 0%, 25%, 50%, 75% and 100% using 360, 1-day-old Arian broiler chicken. The birds were randomly allocated to 30 pens (at density of 0.08 m2/bird) in an open system partially controlled house. The chicks were raised under a photo regimen of 23:1h light to darkness up to 42 days. The five dietary treatments were offered to six replicates of 12 chicks each. Data on productive performance, serum concentrations of urea and uric acid and pH, moisture and nitrogen content of litter were collected at different ages. The mean weight gain, feed intake and feed conversion ratio were significantly decreased in the birds fed on diets containing more than 50% PBM compared to the control birds during days 1–21 of age (P < 0.01). Replacement of FM at different levels with PBM significantly affected either serum urea or uric acid concentrations (P < 0.05). The serum urea and uric acid concentrations was lower in the birds that received 100%-PBM containing diets. The mean nitrogen content of litter was similar among the experimental diets while the moisture content of litter tended to be lower for the birds fed on diets containing 25% PBM compared to the other birds (P < 0.10). No differences in litter pH were pointed out for dietary treatments. Treating the litter samples by Alum significantly increased their pH values (P < 0.01). The results suggest that, substitution of FM with PBM at different levels had no considerable impact on nitrogen contents of litter.

Effects of partial substitution of dietary fish meal by fermented soybean meal on growth performance, body composition and activity of digestive enzymes of juvenile yellowfin sea bream (Acanthopagrus latus)

A feeding trial was conducted to evaluate the effect of replacing fish meal protein with fermented soybean meal (FSM) on the growth performance, feed utilization, body composition and digestive enzymes activity of yellowfin sea bream (Acanthopagrus latus) juvenile. Five isonitrogenic and isolipidic diets were prepared with levels of 0 (control), 100, 150, 250 and 300 g kg -1 FSM. Triplicate groups (20 fish per tank) of yellowfin sea bream with initial weight of 2.51±0.01 g were hand -fed to visual satiation at three meals per day for 56 days. The fish fed diets containing different levels of FSM had no significant differences regarding Final weight, Weight gain, SGR, FCR and Survival with control group. Whole body proximate compositions of fish were not affected by dietary FSM level. The activity of digestive enzymes in the intestine was not affected by dietary FSM level. This study showed that up to 30% fish meal in the diets of juvenile yellowfin (Acanthopagrus latus) could be replaced by fermented soybean meal.

Effect of dietary substitution of fish meal for marine crab and echinoderm meals on growth performance, ammonia excretion, skin colour, and flesh quality and oxidation of red porgy (Pagrus pagrus)

Abstract The present study was conducted to evaluate the effect of feeding marine crab (SMC) meal and sea urchin (SU) meal on growth performance, ammonia-N excretion, skin colouration and final flesh quality and lipid oxidation of red porgy ( Pagrus pagrus ). Fish were fed with five diets: a control-diet (CD); two diets replacing 10% and 20% fish meal protein by protein from SMC meal (SMC10, SMC20), and two diets with 8% and 16% inclusion of SU meal (SU8, SU16). The inclusion of both SMC and SU meals increased fish appetite response reflected in a significantly higher feed intake and final weight. Results were even better for fish fed on SU diets, with improved feed conversion (FCR) and protein utilization (PER). Ammonia-N excretion rates decreased in fish fed on SMC20, SU8 and SU16 diets. Fish skin colouration improved by SMC meal inclusion, while SU meal promoted yellowness colouration in skin. Higher muscle content of arachidonic fatty acid (ARA), was concomitant with the increased level of SMC in diets. The same trend was also found in fillet of fish fed on SU meal diets, with the highest values in ARA content. Results of TBARS in raw fillets showed that the dietary inclusion of SMC meal delayed lipid oxidation compared to FM and SU diets during refrigerated storage.

Effects of partial substitution of dietary fish meal by fermented soybean meal on growth performance, amino acid and biochemical parameters of juvenile black sea breamAcanthopagrus schlegeli

A feeding trial was conducted to evaluate the effect of replacing fish meal protein with fermented soybean meal (FSM) on the growth performance, feed utilization, amino acid profile, body composition, morphological parameters, activity of antioxidant and digestive enzymes of black sea bream (Acanthopagrus schlegeli) juvenile. Five isonitrogenic and isolipidic diets were prepared with levels of 0 (control), 80, 160, 240 and 320 g kg 1 FSM. Triplicate groups (40 fish per tank) of juvenile black sea bream with initial weight of 1.17 ± 0.04 g were hand-fed to visual satiation at three meals per day for 8 weeks. The fish fed diets containing different levels of FSM had no significant differences regarding survival and specific growth rate compared with control group. Feed and protein efficiency ratios of fish fed diet containing 320 g kg 1 FSM were significantly lower than those of control group. Daily feed intake and daily protein intake of fish fed diet containing 240–320 g kg 1 were significantly higher than those of control group. Hepatosomatic index and condition factor of fish were not affected by different dietary FSM level. Fish fed diets containing 240–320 g kg 1 FSM had significantly higher visceral somatic index than control group. Whole body proximate and amino acid compositions of fish were not affected by dietary FSM level. The activity of digestive enzymes in the intestine was not affected by dietary FSM level. The activity of glutathione peroxidase in liver was significantly higher for fish fed the diet containing 160 g kg 1 FSM compared with control group. This study showed that up to 40% fish meal in the diets of juvenile black sea bream could be replaced by fermented soybean meal with supplementation of methionine, lysine and taurine.

Citric acid improves growth performance and phosphorus digestibility in Beluga ( Huso huso) fed diets where soybean meal partly replaced fish meal

A 2 × 3 factorial experiment was conducted to evaluate the effect of partial substitution of dietary fish meal with soybean meal and citric acid (CA) supplementation on growth, food utilization, muscle composition and nutrient digestibility of Beluga, Huso huso. Three isonitrogenic and isoenergetic diets, as SBM 1 (soybean meal protein (SBP):fishmeal protein (FP) = 1:3), SBM 2 (SBP:FP = 2:3) and SBM 3 (SBP:FP = 1:1) containing two levels of CA (0 and 30 g kg −1) were fed to triplicate groups of fish for 8 weeks. The results revealed that adding CA increased (P<0.05) the weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) and decreased (P<0.05) food conversion rate (FCR) whereas partial substitution of fishmeal with soybean meal decreased (P<0.05) growth performance. Partial replacement of fishmeal with SBM (P=0.021) as well as CA supplementation (P=0.019) and their interaction (P<0.001) affected hepatosomatic index (HSI). No differences (P>0.05) were observed for viscerosomatic index (VSI) among treatments (P>0.05). No differences (P>0.05) were detected in moisture, protein of muscle sample among treatments, but lipid content was reduced (P<0.05) while ash content increased (P=0.035) by CA. Soybean meal decreased (P<0.05) nutrient digestibility, whereas CA improved apparent protein and phosphorus (P) digestibility (P=0.011 and P<0.001 respectively). No interaction (P<0.05) between levels of SBM and CA was found on these parameters. Results of the present study indicate that Beluga has a limited ability to utilize SBM as a protein source in practical diets whereas CA can improve growth and nutrient utilization in Beluga.

Effects of the partial substitution of dietary fish meal by two types of soybean meals on the growth performance of juvenile Japanese seabass, Lateolabrax japonicus (Cuvier 1828)

The effect of partial substitution of dietary fish meal with a high-value soybean meal (HVS) and a commercial soybean meal (CSM) on the growth performance in juvenile Japanese seabass (8.3±0.2 g body weight) was determined. Nine isonitrogenous (crude protein 44%) and isoenergetic (20 kJ g−1) practical diets replacing 0 (the control), 15%, 30%, 45% and 60% fish meal protein by soybean meal protein (HVS or CSM) were formulated. Each diet was randomly assigned to four replicate cages (1.5 × 1.5 × 2.0 m). Fish were fed twice daily for 10 weeks. Growth was significantly reduced with increased soybean inclusion in fish fed both the soybean sources. Independent of the soybean source used, increased inclusion of soybean meal decreased the growth performance. When the substitution level was 45% or more in CSM and 60% in HVS, the specific growth rate (SGR) and the feed efficiency ratio (FER) were significantly lower compared with the control. These results indicated that CSM protein could substitute for 30% fish meal protein, while the substitution level of HVS protein could be 45%, which did not influence the growth of juvenile Japanese seabass. The higher substitution level for HVS compared with CSM was probably due to better nutritional values.

Partial substitution of dietary fish meal with soybean meal for speckled shrimp, Metapenaeus monoceros (Fabricius, 1798) (Decapoda: Penaeidae) juvenile

A 63-day feeding study was conducted to evaluate the effect of partial substitution (0%, 20%, 40% and 60%) of dietary fish meal (FM) with soybean meal (SBM) on the growth performance and feed utilization of speckled shrimp, Metapenaeus monoceros juveniles. A total of 180 M. monoceros juveniles with an average weight of 0.67 ± 0.18 g were equally distributed over 12 glass aquaria (30 L each, triplicate per treatment). All aquaria were filled with filtered sea water (30–35 ‰, salinity). Four isonitrogenous (400 g kg−1 crude protein) and isocaloric (20.5 MJ GE kg−1) test diets were formulated. The control diet contained FM (D1) as the main protein source. In the other diets, FM was partially replaced with 20 (D2), 40% (D3) or 60% (D4) SBM. The results indicate that the diet in which 40% of the FM is replaced by SBM yields similar growth and production, and is as cost effective, as the control diet.

Influence of partial substitution of dietary fish meal on the activity of digestive enzymes in the intestinal brush border membrane of gilthead sea bream, Sparus aurata and goldfish, Carassius auratus

The sustainable composition of diets of high nutritional value is of the utmost importance for intensive aquaculture. Digestion and absorption of nutrients depend on the activity of the digestive enzymes, in particular those located in the brush border membrane of enterocytes, which are responsible for the final stages of breaking down and absorption of nutrients. In the present study, the substitution of fish meal by lupin or rapeseed meal in the diet was evaluated on gilthead sea bream ( Sparus aurata) and goldfish ( Carassius auratus). The objectives were to compare the activities of intestinal brush border enzymes in both species fed the control and experimental diets. When gilthead sea bream were fed the vegetable diets, significantly lower activities compared with the control group were observed for alkaline phosphatase and γ-glutamyl transpeptidase, but these differences were not significant in goldfish. Maltase activity was found decreased in the group fed lupin meal, both in sea bream and in goldfish. However, in spite of these differences in enzyme activities, growth characteristics of the fishes were similar with the three diets. It seemed that both fish were able to adapt to partial substitution of fish meal, but it remains to investigate the mechanism for compensating the decrease in specific enzymatic activity in the enterocytes of carnivorous gilthead sea bream.

Effects of the partial substitution of dietary fish meal by differently processed soybean meals on growth performance, nutrient digestibility and activity of intestinal brush border enzymes in the European sea bass ( Dicentrarchus labrax)

This study evaluated the effects of replacing fish meal (FM) in the diet of European sea bass ( Dicentrarchus labrax) with differently processed soybean meals on growth performance; apparent digestibility coefficients (ADCs); the activity of alkaline phosphatase and the brush border digestive enzymes: leucine amino peptidase, maltase and γ-glutamyl transpeptidase; and the fish morphometric and flesh quality. European sea bass with an initial average body weight of 187.8 ± 1.4 g, were fed either a FM based (control) diet or a soy replacement isoproteic, isolipidic and isocaloric diet. The treatments consisted replacing FM protein by: 25% toasted, dehulled and solvent-extracted soybean meal (SE25); 50% dehulled and toasted soy seeds subjected to dry extrusion and mechanical oil extraction (ME50); 50% enzyme-treated soybean meal (ET50) and an inclusion of 60% composed of 30% toasted, dehulled and solvent-extracted soybean meal and 30% enzyme-treated soybean meal (SE + ET/60). ADCs values of dry matter, crude protein, crude lipid and gross energy did not significantly differ between ME50 and SE + ET/60 but both of them were inferior to the other treatments ( P < 0.05). Compared with the control FM-based diet, only the group that consumed the ME50 diet had lower specific growth rate, feed conversion ratio and gross protein retention efficiency values ( P < 0.05). The protein efficiency ratio did not differ between the FM-based control group and all other soy derivate groups ( P > 0.05). In order to gain more insight on the effects of the diet on fish growth, activity of the brush border enzymes was measured. No significant differences were found in leucine amino peptidase and maltase activities, between the control group and the other soy derivate groups. The activity of γ-glutamyl transpeptidase was significantly higher in the upper section in fish that consumed the control diet compared with fish that consumed the soy derivate diets. Yet, the main activity of this enzyme was found in the lower intestinal section. In all the soy derivate diets except for the SE25 diet, the activity of alkaline phosphatase was significantly lower than its activity in the control diet. Feeding diets that include various types and levels of soybean derivatives did not affect the whole body composition and slaughter yield but significantly reduced liver weight. The results show that in methionine supplemented diets, FM can be replaced in terms of protein by 25% SE, 50% ET or 60% soy composed of 30% SE and 30% ET without hampering fish performance. The inclusion of 50% protein from ME resulted in significantly lower growth performance and feed utilization.