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1.
Abstract— The main objective of this study was to determine the effect of different levels of krill meal (KM) as a feed attractant in juvenile Nile tilapia fed soybean (SBM) diets on growth performance, feed utilization, and body composition. Fish of an initial average weight 0.8 × 0.01g were stocked in 18 glass aquaria (80 L each) at a rate of 25 fish per aquarium. Fish meal (FM 20% of the diet) was used as the sole source of animal protein in the control (Diet 1). Diets 2 to 6 had (SBM) protein with various levels of krill meal (0.0,1.5,3.0,4.5, and 6.0%, diets 2-6 respectively). Test diets were fed to satiation to triplicate groups of Nile tilapia four times daily for 20 wk. Fish fed krill meal supplemented diets had significantly ( P < 0.05) better growth performance compared with fish fed the unsupplemented and FM control diets. The krill meal increased growth of Nile tilapia by 31.9% compared to control diets (average Anal wet weight, 14.15 × 0.95 g and 10.72 × 0.2 g, respectively). Moreover, weight gains were not significantly different for fish fed diets with different levels of krill meal. Feed utilization parameters such as feed intake, feed conversion ratio, protein efficiency ratio differed significantly for fish fed krill meal diets compared with control. Digestibility of nutrient and energy of diets increased with increasing levels of krii meal. The incorporation of krill meal in diets significantly affected the protein, fat, ash, and energy of whole body composition. These results suggest that supplementation of krill meal at 1.5% in the diets of Nile tilapia as attractant or stimulant may lead to increased feed intake, growth performance, and feed utilization. Soybean meal can completely replace fishmeal in diets for juvenile tilapia.  相似文献   

2.
The influence of soybean meal (SBM) on the growth and feed utilization of juvenile sutchi catfish (Pangasianodon hypophthalmus, Sauvage, 1878) was investigated. Eight isonitrogenous (300 g kg?1 CP) and isoenergetic (18 MJ kg?1) diets were formulated incorporating Argentine SBM to replace fish meal at 0, 150, 300, 450, 600, 750, 900 and 1000 g kg?1 dietary protein. Each diet was fed to three replicate groups of fish with an initial weight 6.0–6.2 g for twelve weeks. Growth performance decreased, and feed utilization was worsened with the increase in SBM inclusion in the diets. Final weight and relative growth rate (RGR) of fish fed control diet (0 SBM) were significantly higher than those fed test diets (P < 0.05). However, there were no significant differences in the final weight and RGR between the fish fed on 15 SBM, 30 SBM, 45 SBM and 60 SBM diets. Specific growth rate of fish fed 0 SBM, 15 SBM, 30 SBM and 45 SBM diets was significantly higher than those fed other diets. Feed conversion ratio of fish fed 0 SBM, 15 SBM, 30 SBM, 45 SBM and 60 SBM diets was significantly lower than those fed other diets (P < 0.05). The dry matter and protein digestibility were lesser in all the diets in comparison with the control diet. Hepatosomatic index and viscerosomatic index increased with increasing SBM in diet. This present trial indicated that fish meal can be replaced by SBM in the diet of juvenile sutchi catfish only up to 45% of fish meal protein without any adverse effect on growth, feed utilization and body composition.  相似文献   

3.
An 8‐week feeding trial was conducted to evaluate the effects of replacing fish meal (FM) with soybean meal (SBM) and peanut meal (PM) on growth, feed utilization, body composition and haemolymph indexes of juvenile white shrimp Litopenaeus vannamei, Boone. Five diets were formulated: a control diet (FM30) containing 30% fish meal and four other diets (FM20, FM15, FM10 and FM5) in which protein from fish meal was substituted by protein from SBM and PM. The dietary amino acids of diets FM20, FM15, FM10 and FM5 were equal to those of the diet FM30 by adding crystalline amino acids (lysine and methionine). Each diet was randomly assigned to triplicate groups of 30 shrimps (initial weight = 0.48 g), each three times daily. The results indicated that shrimp fed the diets FM15, FM10 and FM5 had poor growth performance and feed utilization compared with shrimp fed the control diet. No difference was observed in feed intake, survival and body composition among dietary treatments. The plasma total cholesterol level of shrimp and the digestibility of dry matter, protein and energy contained in the diets decreased significantly with increasing PM and SBM inclusion levels. Results of this study suggested that fish meal can be reduced from 300 to 200 g kg?1 when replaced by a mixture of SBM and PM.  相似文献   

4.
A total of six isoprotein and isolipid diets for Atlantic salmon, Salmo salar L., were prepared substituting from 0 to 100% of fish meal protein (0–68% of diet by dry weight) with meal from Antarctic krill (Euphausia superba). The feed produced from high inclusion levels of krill meal had lower ability to absorb lipid during vacuum coating than fish meal. Both amino acid and fatty acid compositions of the diets were fairly similar. The experiment commenced using salmon averaging 500 g and ended at a mean weight of 1500–1800 g (140 days of feeding). Moderate amounts of krill meal (20–60% of krill protein) in the diets increased growth during the first 71 days of feeding compared with the fish meal control, while no growth difference was observed during the last 69 days of feeding. This may, at least in parts, be explained by a feed‐attractant function of the krill meal. Muscle dry weight and lipid concentrations were unaffected by the diet. Feed conversion rate increased with high levels of krill meal in the diets (e.g. for the last period from 0.94 in the 0% diet to 1.26 in the 100% diet). This indicates that the fish were able to compensate by eating more to maintain growth. The apparent digestibility coefficients of dry matter and protein were not influenced by diet, but both faecal moisture and lipid had a tendency to increase at the highest inclusion level (all protein from krill meal). This may be related to chitin in the krill diet that is known to decrease lipid absorption and induce diarrhoea (increased water content in faeces). Chitin was not utilized to any major extent. Welfare parameters such as blood haemoglobin, red blood cell counts, plasma protein, cholesterol, triacylglycerols and glucose levels were unaffected by diets. Clinical indicators of cellular damage (alanine aminotransferase and aspartate aminotransferase) were similar indicating no diet‐induced tissue damage during the trial.  相似文献   

5.
Duplicate tanks of c.280 g Atlantic salmon (Salmo salar L.) were fed for 60 days on diets in which fishmeal was substituted with graded levels of extracted soybean meal (SBM) comprising 0%, 10%, 15%, 20%, 25% or 35% of total protein. The effects on feed intake, growth, feed conversion, apparent digestibility and utilization of macronutrients and energy, pathohistological response of the distal intestine (DI), activities of digestive enzymes in the mid and distal intestinal mucosa, and faecal trypsin and plasma insulin concentrations were studied. A negative, dose‐dependent effect of SBM was observed on nearly all performance parameters with a notable exception of feed intake. The lowest SBM inclusion level of 10% resulted in moderate pathohistological changes in the DI. Each subsequent increase in SBM level increased the number of fish displaying severe changes. In contrast to the mid‐intestine (MI), all enzyme activities in the distal intestinal mucosa decreased dose‐dependently with increasing SBM inclusion. Faecal trypsin increased up to an SBM inclusion level of 20% and then levelled off. Plasma insulin increased from 0% to 15% SBM inclusion and then decreased. The results suggest that caution should be exercised in the use of even low levels of extracted SBM in salmon feeds.  相似文献   

6.
Studies were conducted with juvenile (28 g) Atlantic cod (Gadus morhua) and halibut (Hippoglossus hippoglossus) fed fish meal (FM) based diets with partial (0%, 25%, 50% and 75%) or total (100%) replacement of FM with freeze‐dried krill (FDK). Addition of dietary FDK significantly stimulated feeding activity in both species and resulted in higher feed consumption and intakes of digestible protein (DP) and energy (DE). This is a significant finding on the feed attractant properties of FDK because it occurred despite having 2–4 MJ kg?1 higher levels of DE in the FDK diets which could have had an intake suppression effect. In addition, it indicates that the soluble protein fraction of krill thought to be responsible for its attractant properties and is routinely lost or greatly reduced during commercial processing of krill meals, is retained by freeze‐drying. Supplementation of FDK significantly improved growth rates, digestibility and nutrient utilization. Levels exceeding 25–50% FM replacement, however, generally did not significantly increase growth performance or nutrient utilization. In addition, feed formulations with high FDK (>75% replacement) are likely to be cost‐prohibitive as long as the market price remains higher than FM.  相似文献   

7.
This study evaluated the effects of soy protein ratio, lipid content and the minimum dietary level of krill meal in plant‐based diets over the growth performance and digestibility of Litopenaeus vannamei. Nine plant‐based diets varied the soybean meal (SBM) and soy protein concentrate (SPC) inclusion ratio at 1 : 2.3, 1 : 1 and 2.5 : 1, and their dietary lipid content at 121.4 ± 9.4, 102.3 ± 1.2, and 79.9 ± 1.2 g kg?1 (in a dry matter basis). An additional diet containing 120 g kg?1 of fish meal (salmon by‐product) was used as a control. Krill meal was included at 0, 5, 10, 20 and 30 g kg?1 in a new set of plant‐based diets. After 10 weeks in clear‐water tanks of 0.5 m3, no effect of SBM:SPC ratio and dietary lipid content was detected on shrimp survival. However, dietary lipid levels of 80 and 121 g kg?1 combined with a high SPC to SBM resulted in the lowest final body weight and the poorest apparent crude protein digestibility, respectively. Krill meal increased feed intake at only 10 g kg?1, while at 20 g kg?1, it accelerated shrimp growth, increased yield and reduced food conversion ratio.  相似文献   

8.
Antinutritional factors in rapeseed products have been identified to reduce feed palatability and growth performance of turbot. Therefore, we evaluated the potential of blue mussel (Mytilus edulis L.) meal as feed attractant in rapeseed protein‐based diets for turbot. Triplicate fish groups received isonitrogenous and isocaloric diets with fish meal (FM) protein replacements of 50% or 75% by rapeseed protein concentrate (RPC 50, RPC 75). These diets were supplemented with 0%, 2%, 4% or 8% of blue mussel meal. In contrast with RPC 50 diets, fish fed with RPC 75/0 showed significantly reduced daily feed intake (DFI) and specific growth rate (SGR). With increasing mussel meal inclusion, RPC 75 diets resulted in increased DFI and SGR, suggesting mussel meal as attractant in rapeseed protein‐based diets for turbot. Feed conversion was unaffected by any treatment. Protein productive value and apparent digestibility coefficients were unaffected by either RPC or mussel meal inclusion. With regard to the whole body composition, no differences in crude protein, crude lipid and ash content could be determined. Haematological characteristics were unaffected among the treatments indicating good nourished and unstressed fish. In conclusion, we demonstrated that the utilization of blue mussel meal improved the palatability of rapeseed protein‐based diets for turbot.  相似文献   

9.
The effects of two plant ingredients (solvent‐extracted soybean meal [SBM] and high‐protein sunflower meal [HPSFM]) and three inclusion levels (0 percent, practical diet containing 25 percent fish meal; 12.5 percent; and 25 percent) of these ingredients were investigated on the growth, feed utilization, gut histology and gene expression in the distal intestine of Arctic charr Salvelinus alpinus (average initial weight, 330.1 ± 8.9 g per fish). Feeding experimental diets for 12 weeks resulted in no difference between HPSFM diets in body weight gain (BWG), thermal‐unit growth coefficient (TGC), feed efficiency (FE), feed intake (FI) or pro‐inflammatory mRNA expression (PIE) with increasing dietary inclusion and between SBM FE, FI and PIE. Differences in quadratic contrasts were observed for nitrogen deposition rate (NDR) and nitrogen retention efficiency (NRE) (p < .05), whereby HPSFM diets elicited the strongest positive response. SBM resulted in linear reduction in BWG, TGC and distal intestine simple fold length and width measurements (p < .05) with stepwise increases in dietary inclusion, whereas dietary HPSFM had no effect. Histological observations of individual villi indicated several symptoms of non‐infectious subacute gastrointestinal enteritis in tanks fed SBM, many of which were not present in tanks fed HPSFM. The dietary HPSFM seems to be more adequate to replace fishmeal in Arctic charr diet than SBM, when fed at a level of up to 25 percent at the grow‐out stage.  相似文献   

10.
The study evaluated effects of cholesterol supplementation in a diet with high soybean meal (SBM) on the growth and cholesterol metabolism of giant grouper (Epinephelus lanceolatus). All‐fish‐meal diet was used as control. The diet including SBM (replaced 50% of the fish meal protein, SBM diet) and the SBM diet supplemented with 10 g/kg cholesterol (SBM + cholesterol) were used as experimental diets. Three diets were each fed to triplicate groups of juvenile grouper (initial body weight: 12.39 ± 0.36 g) in a recirculating aquaculture system for 8 weeks. Grouper fed the control diet showed higher (p < .05) weight gain, feed intake, feed efficiency and protein efficiency ratio than the other two dietary treatments. Hepatic cholesterol concentrations and 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase gene expressions were higher in fish fed the control diet than fish fed the control diet and SBM + cholesterol diet. Hepatic cholesterol 7α‐hydroxylase gene expression was higher in fish fed the SBM + cholesterol diet than that in fish fed the control diet. Results indicate that giant grouper on a diet low in cholesterol can regulate cholesterol synthesis, suggesting that the reduced dietary cholesterol intake in the fish fed diet containing SBM is sufficiently compensated by increased cholesterol synthesis.  相似文献   

11.
This study aimed to assess the effect of soybean meal (SBM) and cottonseed meal (CSM), as partial replacement of dietary fish meal on growth, feed efficiency (FE) and body mineral composition of juvenile vundu (Heterobranchus longifilis). Five iso‐nitrogenous (390 g kg?1 crude protein) and iso‐caloric (18 kJ g?1, gross energy) diets (Control, SBM30, SBM60, CSM30 and CSM60) were fed to triplicate groups of 40 fish (initial mean weight: 12 g) in each tank (0.9 m3). Over a 7‐week feeding period, significant differences (P < 0.05) were observed on growth, FE and body mineral composition between treatments. Fish‐fed CSM‐based diets and 600 g kg?1 SBM‐based diet had reduced growth and reduced feed and protein efficiencies when compared with those fed diet containing 300 g kg?1 SBM or the control diet. Data from body mineral composition in response to dietary treatment could be divided into two groups. The first group refers to elements such as Mg and Fe for which carcass and fillet composition did not show significant differences with dietary level of SBM or CSM. Ca, P, K, Zn and Mn composed the second group of minerals whose concentrations in fish body were significantly reduced in fish‐fed SBM60. In conclusion, the results of this study indicate that although solvent‐extracted SBM and CSM are often reported safe for fish, they can only partially replace fish meal as a source of protein in compound feed for vundu at a limited amount between 300 and 600 g kg?1 for SBM and <300 g kg?1 for CSM.  相似文献   

12.
The present work was performed to assess whether soybean meal (SBM) could replace fish meal (FM) as a source of dietary protein in diets of the marine herbivore Siganus rivulatus. Five iso-nitrogenous (40% protein) and iso-energetic (14 MJ/Kg) diets were prepared with SBM replacing fish meal at 0%, 25%, 50%, 75%, and 100% dietary protein. A 60-day feeding trial was conducted with 240 juvenile S. rivulatus (initial body mass 1.74 ± 0.03 g). Survival, growth, feed, and protein efficiency and hematological parameters were assessed. Growth correlated negatively with increase in dietary SBM. All production parameters measured were negatively affected at all levels of SBM inclusion. There were no effects on total or differential blood counts, hemoglobin, or plasma protein, but hematocrit values were negatively correlated with SBM addition. Results suggest that total replacement of FM by SBM without adding other supplements is not recommended, even for an herbivorous marine fish such as S. rivulatus.  相似文献   

13.
The present experiment was performed to study how fluoride from krill meal enriched muscle, whole fish and bone of adult Atlantic salmon (Salmo salar) reared in sea water. Atlantic salmon (mean weight 0.5 kg) were divided into four triplicate groups and fed a commercial fish meal based diets with 0, 100, 200 and 300 g krill kg?1 feed, respectively, for 12 weeks. The fluoride concentrations in the experimental feeds were analysed to be 18, 132, 235 and 358 mg kg?1, respectively. Growth, mortality and feed efficiency were recorded through the experiment. Fluoride concentration was measured in muscle, whole‐body, and bone initially and after 12 weeks of feeding. The fluoride concentrations in the samples were determined by alkali fusion and fluoride ion‐selective electrode. Growth, mortality and feed efficiency ratio were not affected by the dietary treatments. The results showed that fluoride concentration in muscle, whole body and bone were not affected by the dietary fluoride level. The fluoride concentration in the tissues showed great variation among replicates of the group given the same diet. Fillets of the fish varied between 0.3 and 1.4 mg fluoride kg?1 wet weight, whereas the whole‐body concentration of fluoride varied between 3.3 and 6.1 mg kg?1 wet weight and the fluoride bone concentration varied between 5.8 and 7.2 mg kg?1 fresh weight. These results suggest that Atlantic salmon are highly tolerant of dietary fluoride given as krill meal with concentration of fluoride up to 350 mg kg?1 diet, and that accumulation of fluoride from feeding diets containing krill meal does not lead to tissue accumulation in the fish, at least over a short period of time.  相似文献   

14.
Four 70‐day growth trials were performed to investigate the effects of substitution of dietary fishmeal (FM) by soya bean meal (SBM) in different sizes of gibel carp CASIII (Carassius auratus gibelio). The initial weights of fry, juvenile, 1‐year fish and broodstock of gibel carp were 0.8, 5.0, 62.7 and 135.6 g, respectively. In each trial, eight diets were formulated to be iso‐nitrogenous and iso‐energetic, and different levels of soy bean meal protein were used to replace fishmeal protein at 0%, 20%, 40%, 60%, 80% and 100%. Another diet containing all SBM protein and supplemented with crystalline amino acids was also tested. The results showed that apparent digestibility coefficients (ADCs) of dry matter and energy decreased with SBM substitution while the ADCs of phosphorus increased. The ADCs of protein of high SBM substitution were higher than those of FM groups. Juveniles show lower ADCs than grown‐up fish. Dietary SBM substitution showed negative effects on survival, growth and feed utilization in gibel carp. One‐year fish and broodstock gibel carp have relatively higher tolerance to dietary SBM than fry and juveniles.  相似文献   

15.
The effects of partial replacement of fish meal (FM) with meal made from northern krill (Thysanoessa inermis), Antarctic krill (Euphausia superba) or Arctic amphipod (Themsto libellula) as protein source in the diets for Atlantic salmon (Salmo salar L.) and Atlantic halibut (Hippoglossus hippoglossus L.) on growth, feed conversion, macro‐nutrient utilization, muscle chemical composition and fish welfare were studied. Six experimental diets were prepared using a low‐temperature FM diet as control. The other diets included northern krill where 20, 40 or 60% of the dietary FM protein was replaced with protein from northern krill, and two diets where the FM protein was replaced with protein from Antarctic krill or Arctic amphipod at 40% protein replacement level. All diets were iso‐nitrogenous and iso‐caloric. Atlantic salmon grew from 410 g to approximately 1500 g during the 160 day experiment, and Atlantic halibut grew from 345 g to 500–600 g during the 150 day experiment. Inclusion of krill in the diets enhanced specific growth rate in salmon, especially during the first 100 days (P < 0.01), and in a dose–response manner in halibut for over the 150 day feeding period (P < 0.05). Feed conversion ratio did not differ between dietary treatments, and no difference was found in dry matter digestibility, protein digestibility and fish muscle composition. Good growth rates, blood parameters within normal ranges and low mortalities in all experimental treatments indicted that fish health was not affected either Atlantic salmon or Atlantic halibut fed the various zooplankton diets.  相似文献   

16.
An 8‐week feeding trial was conducted to evaluate the effects of replacing fish meal with soybean meal (SBM) on growth, feed utilization, and nitrogen (N) and phosphorus (P) excretion of juvenile Pseudobagrus ussuriensis (initial average weight 0.50 ± 0.00 g). Seven isonitrogenous and isolipidic diets were formulated to contain SBM to replace fish meal protein at 0% (S0), 10% (S10), 20% (S20), 30% (S30), 40% (S40), 50% (S50) and 60% (S60) respectively. To investigate the effects of supplementation with crystalline amino acid to balance diet S60, one diet was formulated to add 0.30% methionine (SM60). The results showed that there was no significant difference in weight gain among fish fed S0, S10, S20, S30 and S40 diets, however, a significant reduction in this variable occurred when 50% and 60% of fish meal protein was replaced by SBM (P < 0.05). Apparent digestibility coefficients of dry matter, crude protein and phosphorus of diets were affected by dietary SBM levels. N and P excretion indicate that fish meal replacement by SBM led to an increase in N excretion, but led to a reduction in P excretion. No differences were detected in growth, feed utilization and N and P excretion between fish feed diets S60 and SM60. The results of this study show that 40% of fish meal protein could be replaced by SBM in diets of juvenile P. ussuriensis without having a significant negative effect on growth or feed efficiency, but that higher dietary SBM levels reduce fish performance.  相似文献   

17.
The main objective of the present study was to evaluate the effect of using three different crustacean meals (Tysanoessa inermis, Euphausia superba, Themisto libellula) on product quality of Atlantic salmon (Salmo salar L.). In order to do this, a total of six iso‐protein, iso‐lipid and iso‐carotenoid diets were prepared. Two experimental diet series were prepared. In the first series, a control feed (K0) was compared with diets where 20%, 40% and 60% of the fish meal protein were replaced with protein from Northern krill T. inermis (K20, K40 and K60, respectively). In the second series, control feed (K0) was compared with diets where 40% of the dietary protein was replaced by protein from T. inermis (K40), Antarctic krill E. superba (AK40) and the Arctic amphipod T. libellula (AMP40). The salmon groups were fed the various diets for 160 days and the average weight of the fish increased from 410 g to around 1500 g. Fish given diets containing krill displayed a general better growth compared with the ones given pure fish meal diet. Replacing fish meal protein with protein from the crustacean sources had, in general, only minor effects on the flesh quality measured both by technical and sensory methods. However, some significant effects were noted. Postmortem muscle pH was generally lower (P < 0.05), for K20, K40, AMP40 in fish fed crustacean diets compared with those receiving the control diet. Increasing the replacement level of non‐fish meal protein from Northern krill (K20, K60) significantly reduced the rigor contraction. Fish given K20 had a slightly firmer meat texture, measured as resistance to post‐rigor compression, especially when compared with K60 (P < 0.05). Fish from the K20 and AMP40 groups had a deeper red flesh coloration [both light reflection (A*‐value and chroma) and flesh astaxanthin concentration] than fish fed K0 and higher inclusions of krill meal. The groups with the highest astaxanthin flesh content also showed the best growth and had the highest feed intake. Finally, a sensory panel analysis differed slightly from the technical measurements in that K0, rather than K20 was given the highest score for hardness and colour. In comparison with K0, AK40 got the lowest salty taste and hardness scores from the panellists relative to the control fish (P < 0.05). Despite minor effects on the present quality measures, it is concluded that meal from three different crustacean species can successfully replace fish meal up to 60% with Northern krill, and 40% of Antarctic krill and amphipod meal of dietary proteins.  相似文献   

18.
An 11‐wk feeding trial was conducted to evaluate three different protein hydrolysates as feed ingredients in high‐plant‐protein diets for juvenile olive flounder. Five experimental diets were fed to juvenile olive flounder to examine the effect of three different protein hydrolysates on growth performance, innate immunity, and disease resistance against bacterial infection. A basal fishmeal (FM)‐based diet was regarded as a high‐FM diet (HFM) and a diet containing soy protein concentrate (SPC) as a substitute for 50% FM protein was considered as a low‐FM diet (LFM). Three other diets contained three different sources of protein hydrolysates, including shrimp, tilapia, and krill hydrolysates (designated as SH, TH, and KH), replacing 12% of FM protein. All diets were formulated to be isonitrogenous and isocaloric. Triplicate groups of fish (15.1 ± 0.1 g) were handfed one of the diets to apparent satiation twice daily for 11 wk and subsequently challenged against Edwardsiella tarda. Growth performance and feed utilization of fish fed hydrolysate‐supplemented diets were significantly improved compared to those of fish fed the LFM diet. Dietary inclusion of the protein hydrolysates significantly enhanced apparent digestibility of dry matter and protein of the diets. In the proximal intestine, histological alterations were observed in the fish fed the LFM diet. The fish fed the hydrolysate diets showed significantly longer mucosal fold and enterocytes and greater number of goblet cells compared to fish fed the LFM diet. Respiratory burst activity was significantly higher in fish fed the TH and KH diets than fish fed the LFM diet. Significantly higher immunoglobulin levels were found in fish fed SH and KH diets compared to those of fish fed the LFM diet. Dietary inclusion of the protein hydrolysates in SPC‐based diets exhibited the highest lysozyme activity. Significantly higher superoxide activity was observed in groups of fish fed the KH diet. Fish offered the protein hydrolysates were more resistant to bacterial infection caused by E. tarda. The results of this study suggest that the tested protein hydrolysates can be used as potential dietary supplements to improve growth performance and health status of juvenile olive flounder when they were fed a LFM diet.  相似文献   

19.
Antarctic krill (Euphausia superba) and other marine zooplankton may contain high levels of fluoride. The aim of the present experiment was to determine whether dietary fluoride from Antarctic krill at levels similar to the old and the new EU allowable limits in fish feeds (150 and 350 mg kg?1) would induce kidney lesions in freshwater‐reared Atlantic salmon (Salmo salar). In addition to the diets containing krill, two high‐sodium fluoride (NaF) diets (1500 and 3500 mg kg?1) were used to investigate the effect on growth, feed intake, faecal excretion of minerals and accumulation of fluoride in various tissues. No major effects on growth or feed intake were observed. A higher proportion of the ingested fluoride was absorbed in salmon fed with the NaF diets compared with fish fed with krill shell diets. Fluoride accumulated in liver, kidney and especially bone. Faecal excretion of calcium and magnesium was higher for the NaF‐fed fish compared with fish fed with the control and krill shell diets, whereas the levels of these minerals in plasma were unaffected. Dietary fluoride from krill shells did not induce kidney lesions. One‐third of the salmon fed with the highest NaF diet showed signs of crystal formation within the distal tubules and/or collecting ducts in the kidney.  相似文献   

20.
Two trials with Atlantic salmon (Salmo salar) were conducted to evaluate the potential of krill meal to improve feed intake. In the first experiment, after transfer to sea water, salmon smolts were fed diets added 75 or 150 g kg?1 Antarctic krill meal in substitution for fish meal for 13 weeks. The apparent digestibility coefficient for crude protein and the majority of the amino acids was significantly lower in the feeds added krill meal (around 83.5%) than in the control diet (84.9%), whereas the digestibility of crude lipids, dry matter and energy was not significantly different among the three diets. Krill meal addition resulted in higher feed intake, which led to higher growth rates and final body weights. In the second experiment, large salmon were fed a diet containing 100 g kg?1 krill meal for 6 weeks before slaughter. Their feed intake and growth performance were assessed, and fillet and visceral fat contents were measured. Salmon fed the 100 g kg?1 krill meal diet tended to eat more, resulting in significantly increased growth rates, when compared to control fish. Fish fed krill meal also had a significantly lower condition factor.  相似文献   

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