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1.
Welfare in farmed fish got particular attention during the last decades from both governmental and public sides. In aquaculture context, welfare concerns are mainly related to handling procedures, water quality and stoking densities. In Europe, authorities had to clarify the threshold limits of stocking densities to maintain fish good welfare, including for organics aquaculture through the EC regulation 710/2009. However, effects of stocking density on fish welfare are complex and sometimes contradictory. Moreover, there is a lack of knowledge about the impact of density on fish welfare in organic aquaculture. Thus, the aim of the study is to asses welfare state of rainbow trout (Oncorhynchus mykiss) at two initial stocking densities (low density, LD: 12 kg/m3 and high density, HD: 17 kg/m3) fed using organic feed by combining the monitoring of growth performances, behaviour (swimming activity) and physiological indicators (i.e. cortisol, glucose, lactate, hematocrit, red blood cellule count and lysozyme). At the end of experiment, the stocking density reached 21 kg/m3 and 30 kg/m3 for the LD and HD respectively. Overall, growth performances, swimming activity and level of physiological indicators of stress and welfare were similar between HD and LD over the experiment duration. To conclude, we observed no alteration of fish welfare between the two stocking densities monitored. This study suggests that a final stocking density of 30 kg/m3 can be considered for organic aquaculture of rainbow trout respecting welfare.  相似文献   

2.
In the present study, potential ameliorative effects of dietary ginger (GN) were investigated on antioxidant and immune responses of rainbow trout (Oncorhynchus mykiss) during oxytetracycline (OX) administration. As a 2 × 3 factorial design, the fish were orally treated with OX (a daily dose of 100 mg/kg) and GN (either 10 or 20 g/kg diet) for 10 days. Then, blood samples were taken from each treatment to monitor plasma lysozyme, complement (ACH50), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione‐S‐transferase (GST) activities, and reduced glutathione (GSH), malondialdehyde (MDA), total immunoglobulin (Ig) and globulin levels. OX treatment significantly decreased SOD (30%), GPx, (10%) and lysozyme (23%) activities, and GSH (19%) levels; however, it increased GST (16%) activity and MDA (28%) levels. Ten grams GN per kg levels significantly decreased SOD (35%), CAT (13%), GST (20%) and MDA (30%), but increased GSH (30%), lysozyme (48%) and globulin (16%). Twenty grams GN per kg diet significantly decreased SOD (26%) and MDA (17%), but increased lysozyme (31%) levels. Interaction effects of dietary GN and OX were observed on plasma MDA and GPx levels, as 10 g GN per kg diet prevented the OTC‐induced changes in these parameters. Moreover, 20 g GN per kg diet prevented the OX‐induced change in GPx activity and mitigated the MDA elevation by 20%. It is concluded that GN administration at 10 g/kg diet is beneficial in mitigating oxidative stress and immunosuppression of rainbow trout during OX administration.  相似文献   

3.
The effects of diet supplemented with Myrcia sylvatica essential oil (EOMS) on growth and stress tolerance to different stocking densities were assessed in Sparus aurata. Initially, three experimental groups were established: (i) control, (ii) 1.0 and (iii) 2.0 ml EOMS/kg dry feed. After 90 days, nine fish per group were anaesthetized, weighed and sampled for metabolic analysis. The remaining fish were divided into two different conditions: low (LD—5 kg/m3) and high (HD—40 kg/m3) stocking densities, constituting a final experimental setup with six treatments. After 22 days, 10 individuals per treatment were anaesthetized and sampled for biochemical analysis. EOMS feeding for 90 days did not interfere with growth, although it was effective in reducing cortisol levels and the activation of lipid and carbohydrate metabolism. The HD interfered in growth performance, increased the lactate levels in the control group, reducing also hepatic glycogen levels without dependence on diet supplementation. The 2.0 ml EOMS + LD group increased the growth parameters and decreased the cortisol and triglycerides levels. Additionally, metabolism adjustment was observed to provide energy during LD and HD conditions, indicating that diets supplemented with EOMS produce metabolic reorganization to maintain body homeostasis, suggesting its use as a beneficial supplement in fish.  相似文献   

4.
The aim of the present study was to evaluate the potential effects of olive leaf (Olea europea L.) extract (OLE) on common carp (Cyprinus carpio) health in response to ambient ammonia toxicity. Fish were fed with experimental diets containing OLE (0, 1, 5 and 10 g/kg) for 60 days followed by a 3‐hr challenge with ammonia (0.5 mg/L unionized ammonia‐N). Results showed that haemoglobin levels, differential leucocyte counts and mean corpuscular haemoglobin concentration were not affected by dietary OLE levels and ammonia challenge. Ammonia challenge significantly increased red blood cells and decreased blood mean corpuscular volume, mean corpuscular haemoglobin, plasma lysozyme, complement and bactericidal activities. Plasma lysozyme, complement and total immunoglobulin values improved by 5 and/or 10 g OLE/kg supplementation. Before the ammonia exposure, the 5 and 10 g OLE/kg treatment significantly increased blood white blood cell, but there was no significant difference among the treatments after the ammonia exposure. Ammonia exposure significantly increased plasma malondialdehyde levels; however, 1 and 5 g OLE/kg treatments had significantly lower values compared to the other treatments. The present results suggest that 1 g OLE/kg diet may improve fish health and reduce the adverse effects of ammonia toxicity on common carp.  相似文献   

5.
The main aim of the present study was to assess the effects of chronic high stocking density on liver proteome of rainbow trout. Rainbow trout juveniles (42.6 ± 2.3 g average body weight) were randomly distributed into six tanks at two stocking densities (low stocking density (LD) = 20 kg m?3 and high stocking density (HD) = 80 kg m?3). Both treatments were performed in triplicate tanks for a period of 60 days. High stocking density caused a reduction in the growth performance compared with LD fish. Lysozyme activity increased with stocking density, while serum complement activity presented the opposite pattern. Serum cortisol and total protein levels did not show significant differences (P > 0.05) between experimental groups. The fish reared at high stocking density showed significantly lower osmolality and globulin values but higher albumin level. The HD group had significantly higher activities of catalase, glutathione peroxidase and superoxide dismutase, and malondialdehyde content in the liver when compared to the LD group. Comparative proteomics was used to determine the proteomic responses in livers of rainbow trout reared at high stocking density for 60 days. Out of nine protein spots showing altered abundance (>1.5-folds, P < 0.05), eight spots were successfully identified. Two proteins including apolipoprotein A-I-2 precursor and mitochondrial stress-70 protein were found to increase in HD group. The spots found to decrease in the HD group were identified as follows: 2-peptidylprolyl isomerase A, two isoforms of glyceraldehydes-3-phosphate dehydrogenase, an unnamed protein product similar to fructose-bisphosphate aldolase, 78 kDa glucose-regulated protein, and serum albumin 1 protein.  相似文献   

6.
We assessed the effects of a fishmeal (FM)‐ and two soya‐based diets [without or with prebiotic (GroBiotic® ‐A; GBA) supplementation] on the production performance, non‐specific immunity, blood parameters and gut microbiota diversity of red drum, Sciaenops ocellatus. All diets were formulated to contain 450 g/kg crude protein (CP) and 120 g/kg lipid. A combination of soya bean meal and soya protein concentrate (SP) was used to replace 88% of the FM in the FM‐based diet (REF) originating the first soya‐based diet (SOY). The second soya‐based diet (SOY + GBA) was designed identically to SOY except for the supplementation of GBA (20 g/kg) substituting for wheat flour. After feeding the experimental diets to triplicate groups of 25 (~3.4 g/fish) and 90 (~4.1 g/fish) red drum juveniles for 9 (Trial I) and 16 weeks (Trial II), our results showed that (i) red drum was highly sensitive to the soya‐based diets in the first week of feeding; (ii) replacing 88% of FM with SP reduced the production performance of red drum without affecting intestinal micromorphology; (iii) whole‐blood leucocyte oxidative radical production was unaffected while lower haematocrit and higher plasma lysozyme activity were found in fish fed REF; (iv) plasma osmolality was unaffected while lower glucose and higher lactate levels were observed in fish fed SOY and SOY + GBA; (v) 16S rRNA gene‐based diversity of fish gut microbiota was affected both by SP and by GBA. This study expands the information on red drum responses to soya‐based diets and prebiotic supplementation.  相似文献   

7.
The effects of dietary hydroalcoholic extract of honeybee pollen (HBPE) on growth performance, flesh quality, immunity and stress response were investigated. Two hundred fifty‐five rainbow trout (11.14 ± 1.06 g) were fed five diets containing increasing levels of HBPE: control, 0.25HBPE (0.25 g HBPE/kg), 0.5HBPE (0.5 g HBPE/kg), 1HBPE (1 g HBPE/kg) and 1.5HBPE (1.5 g HBPE/kg). After 56 days, rainbow trout fed the 0.5HBPE and 1HBPE diets displayed significantly higher weight gain (49.58 and 53.25 g) and protein efficiency (2.88 and 2.83) compared to those fed the control diet (4.89 and 2.05), respectively (p < .05). For flesh quality, higher protein content in the whole body of fish fed the 1HBPE (633.3 g/kg) and 1.5HBPE (640.9 g/kg) diets was observed when compared to other groups (p < .05). There were no significant differences in the saturated and monounsaturated fatty acid content. Individuals fed the 1HBPE (234.5 g/kg) and 1.5HBPE (234.7 g/kg) diets exhibited higher levels of n‐3 long‐chain polyunsaturated fatty acids in the muscle than the other groups (p < .05). In terms of the immune system, the serum lysozyme and alternative complement pathway haemolytic activity levels in the 0.5HBPE (47.66 and 148.00 U/ml) and 1HBPE (46.00 and 146.33 U/ml) treatments were higher than the other treatments (p < .05). When Aeromonas hydrophila was exposed to different dosages of HBPE, a higher inhibitory zone resulted from 1,000 and 1,500 mg/ml dosage. The lower levels of plasma cortisol were observed in the 1HBPE and 1.5HBPE groups after the complement stress test. Collectively, the present findings suggest that the 1HBPE diet supported superior growth, flesh quality, immunity and stress response of rainbow trout.  相似文献   

8.
This research was designed to determine the effects of rosemary (Rosmarinus officinalis) extract on growth, blood biochemistry, immunity, antioxidant, digestive enzymes and liver histopathology of rainbow trout. In a 40‐day diet experiment, rainbow trout was fed with the experimental diets containing 0.4, 0.7, 1 and 3 g/kg of rosemary. 0.4 and 0.7 g/kg rosemary extracts had no significant effect on all parameters studied (p > .05). The growth performance (SGR and WG) and feed utilization (FCR and FER) of the fish increased with the increase in the rate of rosemary in the feed (p < .001). Additionally, only the final weight levels were significant at the linear level (p < .05). Rosemary's 1 and 3 g/kg doses increased total protein, trypsin, amylase, lipase, superoxide dismutase (SOD), catalase (CAT), lysozyme, total immunoglobulin (IG) and white blood cell (WBC) levels when compared to control group. However, glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol and triglyceride levels decreased significantly (p < .001). Moreover, these doses of rosemary caused a significant reduction in steatosis of liver hepatocytes compared to the control group. In conclusion, the present study showed that rosemary may be useful in reducing the stress effects by increasing the growth, antioxidant, digestive enzymes and immunity levels, as well as reducing the rate of steatosis in the liver of rainbow trout.  相似文献   

9.
This study aimed to assess the effects of stocking density on the growth, antioxidant status, and physiological response of juvenile turbot. Turbot (average initial weight 70.0 ± 5 g) were reared at three different initial densities (low density [LD], 5.13 ± 0.03 kg/m2; medium density [MD], 7.71 ± 0.11 kg/m2; and high density [HD], 10.8 ± 0.12 kg/m2) for 80 d. At the end of this trial, the final densities were 13.2 ± 0.10, 19.9 ± 0.15, and 25.7 ± 0.12 kg/m2 in the LD, MD, and HD groups, respectively. The growth performances were adversely influenced by a high stocking density. Levels of cortisol, glucose, cholesterol, triglyceride, glutamate pyruvate transaminase, and glutamate oxalate transaminase in the plasma significantly increased in HD treatment. Results of oxidative stress analyses showed that there was a clear decrease in superoxide dismutase, glutathione peroxidase, catalase, glutathione, and total antioxidant capacity, and an obvious increase in malondialdehyde in plasma and/or liver of turbot reared in HD group (P < 0.05). Overall, the results indicated that increasing stocking density reduced the growth performance, modulated the physiological response, and induced oxidative stress in turbot.  相似文献   

10.
The present investigation aimed to evaluate the effect of dietary chitosan supplementation on growth performance, body composition, immune response and histopathology of Nile tilapia, and also the in vitro antibacterial activity of chitosan against Streptococcus agalactiae (S. agalactiae). About 180 fish (average body weight 39.3 ± 0.3 g) were randomly divided into three groups according to chitosan supplementation: control group (basal diet without chitosan), Ch3 group (3 g chitosan/kg diet) and Ch5 group (5 g chitosan/kg diet). Growth performance parameters and body proximate composition were measured before infection but biochemical parameters and lysozyme and antibacterial activities before and after experimental infection. Results of the present investigation showed dietary chitosan (5 g chitosan/kg diet) significantly (p < .05) improved growth performance parameters, body composition (dry matter, crude protein, ether extract, ash, and carbohydrate) and serum biochemistry (total protein, albumin, globulin, with no effect on AST, ALT, urea and creatinine) before infection in Ch5 group than the control. After infection, liver enzymes (serum AST and ALT) were maintained lower in fish fed Ch3 or Ch5 than the control. Serum lysozyme and bactericidal activities significantly increased (p < .05) in chitosan groups before and after the challenge. The mortality rate was markedly reduced in the Ch3 group and prohibited in the Ch5 group after the experimental infection. In conclusion, feeding 3 or 5 g chitosan/kg diet increased the growth rate and improved FCR of Nile tilapia. In addition, it reduced mortality by its antibacterial and immunostimulant effects.  相似文献   

11.
In order to study the effects of linseed oil substitution on the growth, body composition, tissue fatty acid composition, flesh nutritional value and immune indices of juvenile Manchurian trout, five feed types containing different levels of linseed oil (LO) mixed with fish oil (FO) were prepared: 0 (0 LO); 250 g/kg (25 LO); 500 g/kg (50 LO); 750 g/kg (75 LO); and 1000 g/kg (100 LO); and fed to juvenile Manchurian trout (initial weight 6.43 ± 0.02 g) for 9 weeks. The results showed that substitution of FO with 750 g/kg LO did not affect the growth of juvenile trout, with protein content in the dorsal muscle, and lipid content in the liver not showing any significant difference (p > 0.05). The highest lipid content found in muscle samples occurred for the 25 LO diet. The fatty acid composition found in the dorsal muscle and the liver of the Manchurian trout reflects the fatty acid composition in the diet, where the relative amount of linolenic acid (ALA), linoleic acid (LA) and docosahexaenoic acid (DHA) found in these organs has a positive linear correlation with their relative composition in the diet (p < 0.05). As the amount of LO in the diet was increased, the composition of ALA found in the sampled organs increased, while the composition of DHA and eicosapentaenoic acid (EPA) decreased. At the same time, the index of atherogenicity (IA) and thrombogenicity (IT) of the muscle samples from the 75 LO and 100 LO diets was significantly lower than for the 0 LO and 25 LO diets (p < 0.05), while the flesh lipid quality (FLQ) in the 100 LO diet was significantly lower than for the other diets (p < 0.05). The aspartate transaminase (AST) activity decreased initially, and then increased, as the level of LO replacement for FO was increased, with the 25 LO diet being significantly lower than for other groups (p < 0.05). The alanine aminotransferase (ALT) activity in serum samples from the 100 LO diet was higher than that from other diets. The lysozyme (LZM) activity in both serum and liver tissue first increased to a peak for the 25 LO and 50 LO diets, respectively, and then decreased as the level of LO was further increased. There was no significant change in the alkaline phosphatase (AKP) activity in the liver samples; however, the acid phosphatase (ACP) activity decreased significantly from the highest value for 0 LO feed group. In conclusion, the composition of fatty acids in the dorsal muscle and the liver was found to be modified by the diets, and with the diet containing less than 750 g/kg LO, being both beneficial for growth, and improved immunity, while maintaining the nutritional value of the lipid content in the dorsal muscle during the 9‐week period.  相似文献   

12.
In previous study, the effects of synthesized chitosan/zeolite and nanochitosan/zeolite composites on rainbow trout growth, digestive enzyme activities and some biochemical parameters were shown. In this study, the effects of experimental diets based on the previous study on the rainbow trout intestinal histology and stereology were assessed: control diet (no zeolite and composite), T1 diet (14.28 g/kg zeolite), T2 diet (0.05 g/kg chitosan included in zeolite), T3 diet (0.5 g/kg chitosan included in zeolite), T4 diet (5 g/kg chitosan included in zeolite), T5 diet (0.05 g/kg nanochitosan included in zeolite), T6 diet (0.5 g/kg nanochitosan included in zeolite), T7 diet (5 g/kg nanochitosan included in zeolite). The experiment was conducted for 60 days. Results showed that supplemental diets did not have side effect on the normal structure of intestinal segments but administration of T1 and T4 diets had slight negative effects on structural maintenance in the middle part of intestine. Acidic mucin producing goblet cell percentage was also higher in nanocomposites‐administrated groups in comparison with the control group. Enhanced villus height, density and finally absorption surface area in different parts of rainbow trout intestine were mainly shown in T7 group. Meanwhile, higher thickness of tunica mascularis in different regions were noted in treatment groups especially in T7 group. The number of intraepithelial mononuclear leukocytes in fish intestine received treatment diets was also higher than control group. In conclusion, nanochitosan/zeolite composites in comparison with zeolite and chitosan/zeolite composites were more effective to improve histological structure of rainbow trout intestine.  相似文献   

13.
The present study was conducted to explore the effects of graded replacing fishmeal (0, 50, 100 and 150 g/kg) with chicken plasma powder in diets for largemouth bass, and each diet was fed to triplicate groups of fish (initial weight: 49.50 ± 0.07 g) twice daily. Results showed that specific growth rate was not remarkably reduced until 150 g/kg fishmeal being replaced. Meanwhile, the inclusion of chicken plasma powder led to a significant decrease in feed intake, and the replacement of 150 g/kg fishmeal significantly decreased the apparent digestibility coefficient of protein and essential amino acids, which may account for the lowered protein retention rate and decreased crude protein content of liver and whole body composition. Moreover, the replacement of 150 g/kg fishmeal resulted in a significantly reduced activity of lysozyme, classical complement pathway and respiratory burst, and meanwhile, the red blood cell count and haemoglobin content were also significantly reduced, indicating the impaired health status of fish with high inclusion of chicken plasma powder. In above, approximately 50–100 g/kg fishmeal could be replaced by chicken plasma powder in the diets for largemouth bass.  相似文献   

14.
To determine the effect of dietary supplementation of A3α-peptidoglycan (A3α-PG), extracted from Bifidobacterium sp. cell wall, on the immune responses of Japanese flounder (Paralichthys olivaceus) and explore a possible influence of doses and administration length, a 40-day feeding trial was conducted to evaluate graded levels (0, 0.5, 1, 2, 4, 8 and 16 g A3α-PG/kg diet) in the diet of juvenile Japanese flounder, followed by a challenge with Vibrio anguillarum by intraperitoneal injection. Growth, serum lysozyme, hemolytic complement activity, blood leucocyte phagocytic activity, respiratory burst, and total serum protein were monitored at intervals of 10, 20, 30 and 40 days.Growth, serum lysozyme, hemolytic complement activity, blood leucocyte phagocytic activity of juvenile Japanese flounder were generally enhanced by dietary supplementation of 1, 2, 4 and 8 g A3α-PG/kg diet and also enhanced immune responses, but not growth. The beneficial influence of A3α-PG on most of the tested immune responses were dose- and/or administration length-dependent except serum lysozyme, which was only stimulated by higher doses (more than 2 g A3α-PG/kg) after 40 days feeding. No significant influence of dietary supplementation of 0.5 g A3α-PG/kg on innate immunity was observed on juvenile fish. The highest dose explored in the present study, 16 g A3α-PG/kg, also failed to show any significant influences, although no obvious pathology was observed. Dietary supplementation of A3α-PG showed protection against V. anguillarum. The present study showed an immunomodulatory effect of dietary supplementation of A3α-PG and the potential use in health management of cultured economic fish species such as Japanese flounder.  相似文献   

15.
A 60‐day feeding trial was conducted to evaluate effects and interactions of dietary Nano selenium (Nano Se) and vitamin E on performance of rainbow trout under high rearing density (80 kg/m3). Fish (42.6 ± 2.3 g) were stocked into 12 tanks: Control group fed basal diet and three treatment groups fed basal diet supplemented with 1 mg/kg Nano selenium (Nano Se group), 500 mg/kg vitamin E (Vit E group) and both micronutrients (Combination group). Results showed that growth, feed intake, lysozyme activity and agglutination antibody titre were significantly higher in Vit E and Combination groups. The lowest haematocrit, haemoglobin and cortisol levels and highest serum total protein and muscle crude protein were observed in Combination group. Serum globulin content was higher and albumin: globulin ratio was lower in treatment groups compared with Control. Also, the highest muscle catalase, superoxide dismutase and glutathione peroxidase activities and lowest malondialdehyde content were observed in Combination group compared with Control. In conclusion, combined supplementation of Nano Se and vitamin E provides a synergistic interaction in preventing the immunosuppressive action of oxidative stress caused by high density and significantly improved antioxidant and immune systems, health status and growth of fish under intensive culture.  相似文献   

16.
The oilseed Camelina sativa has been studied as a lipid source for farmed salmonids, but recommended inclusion as a protein source has not been determined. This study evaluated low inclusion of camelina high‐oil residue meal (HORM) at 20, 40 and 60 g/kg of the diet, to determine an adequate level for Atlantic salmon parr (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Salmon and trout were fed experimental diets containing up to 60 g/kg HORM for 16 weeks. At 40 g/kg HORM, trout and salmon growth performance were similar to those fed a control diet. However, at 60 g/kg HORM, trout showed lower final weight, weight gain and feed intake than those fed the control diet. Rainbow trout fed 40 and 60 g/kg HORM showed significantly lower whole body ash (p = .005), slightly lower whole body protein levels and higher fat than the control. In salmon fed 60 g/kg HORM diets, whole body ash (p = .024), and the submucosal layer of the intestine was thicker than the control (p = .007). Current results indicate that up to 40 g/kg HORM can be included in diets for rainbow trout and salmon juveniles.  相似文献   

17.
Juvenile Strongylocentrotus droebachiensis (average wet weight = 4.0 g) were held at three initial stocking densities (15, 30 and 60 animals per tray, which equates to 0.25, 0.5 and 1 kg sea urchins/m2 surface area, respectively) under constant light and temperature conditions (LD 24:0 and 8.8°C) for 380 days. The somatic growth and survival of the urchins were monitored during this period, and the gonad index (GI) was measured at the conclusion of the experiment. The sea urchins in the two lowest stocking density groups had 100% survival after 380 days in contrast to the highest stocking density group, which only had 67% survival at the conclusion of the experiment. Somatic growth was significantly higher in the lowest density group than in the medium density group, and this in turn was significantly higher than in the high-density group. The injury occurrence was highest in the high-density group (20%), lower in the medium group (7%), and there were no injuries observed (0%) in the low density groups. There were no significant differences in GI between the groups at the end of the experiment. In conclusion, the present study showed that stocking density has significant effects on somatic growth and survival of juvenile green sea urchin, S. droebachiensis and should be taken into consideration when designing sea urchin holding systems.  相似文献   

18.
Effects of graded dietary levels of fish meal (FM) replacement with meat and bone meal (MBM) with garlic powder (G) or without garlic powder (WG) garlic powder were investigated on growth, digestive enzymes, apparent digestibility, body composition and fatty acid profile of juvenile rainbow trout (Oncorynchus mykiss; 8.26 ± 1.10 g). A total of eight dietary treatments were evaluated: control with garlic powder (0 MBM+G), 250 MBM+G, 450 MBM+G, and 650 MBM+G (g MBM/kg diet; treatments with garlic powder; G treatments), control without garlic powder (0 MBM), 250 MBM, 450 MBM and 650 MBM (g MBM/kg diet; treatments without garlic powder; WG treatments). Our results demonstrated that increased dietary content of MBM impaired growth and production performance, body composition, digestive enzyme activity, tissue fatty acid profile and overall digestibility. Addition of garlic powder was able to correct fish performance, body composition, enzyme activity and digestibility to some extent. Dietary supply of garlic resulted in increased digestive enzyme activity improving fish performance. The current results indicated that fish fed 650 g MBM/kg feed exhibited impaired growth that could be attributed to reduce digestibility of protein, fat, energy and dry matter, PUFAs and n‐3 LC‐PUFAs in muscle. We suggest that 450 g FM per kilo feed can be successfully replaced with MBM supplemented with 30 g garlic powder per kilo feed without impairing fish performance and physiology, however distorting tissue fatty acid composition resulting in lesser levels of n‐3 LC‐PUFAs compared to the 0 MBM+G diet.  相似文献   

19.
A 12‐week trial was performed with rainbow trout (Oncorhynchus mykiss) utilizing combinations of ingredients at two nutrient targets. Ingredient combinations were fishmeal‐based diet (FMD), animal product‐based diet (APD), plant product‐based diet (PPD), novel plant‐based diet (NPD) and potential future plant‐based diet (FPD). Two nutrient concentrations were targeted: 1) to meet published amino acid targets for rainbow trout utilizing approximately 450 g/kg crude protein (400–420 g/kg digestible protein) and 2) to meet the amino acid targets based on ideal amino acid balance of trout muscle for Lys, Met and Thr utilizing approximately 400 g/kg crude protein (370–380 g/kg digestible protein). Interactive effects between ingredient combination and nutrient concentration occurred across all response variables. When diets were formulated to Target 1, fish consuming FMD and APD displayed better weight gain and feed conversion ratio (FCR) than plant‐based diet, while graded effects were found within the plant‐based treatments. When differing ingredient combinations were utilized and formulated to Target 2, fish grew equally well except for the NPD treatment which supported lower growth and higher FCR. Based on the data from the current experiment, one can completely remove fishmeal from trout feeds and reduce protein levels when dietary digestible amino acids are balanced.  相似文献   

20.
A 63‐day experiment was done to study the effects of four levels (5, 10, 20 and 50 g/kg) of encapsulated organic salts (Na‐acetate, Na‐butyrate, Na‐lactate and Na‐propionate) on the growth indices and haemato‐immunological responses of crayfish Astacus leptodactylus leptodactylus (4.38 ± 0.08 g). Crayfish were distributed at 51 1,000‐L tanks (17 treatments at triplicate). The highest values of final weight (27.86 g), specific growth rate (2.94% body weight per day) and survival rate (96%) were observed in the crayfish fed the 20 g/kg of encapsulated Na‐propionate diet (p < .05). The highest activities of phenoloxidase (7.4 U/min), superoxide dismutase (7.80 U/min) and lysozyme (9.40 U/min) were observed in the gut of crayfish fed the 20 g/kg of encapsulated Na‐propionate diet (p < .05), as well as the highest activities of alkaline protease (10.70 U/mg), lipase (9.10 U/mg), amylase (9.60 U/mg) and the lactobacillus count (p < .05). Broken line regression model of SGR and phenoloxidase activity suggested that the optimum dietary levels of encapsulated Na‐acetate, Na‐butyrate, Na‐lactate and Na‐propionate could be 30.7, 31.8, 31.4 and 33.5 g/kg, respectively, in crayfish reared in culture conditions.  相似文献   

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