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1.
Nutritional strategies to reduce both phosphorus (P) and nitrogen (N) excretion relative to growth of rainbow trout were tested in a 2 × 3 factorial experiment. The two factors were `dietary P level' and `dietary lipid level.' Reduction in dietary P from 14 to 8 g kg–1 dry diet was achieved by partial substitution of dietary fish meal with a combination of full-fat soyabean meal, corn gluten and spray-dried blood meal. Triplicate tanks of 35 rainbow trout per tank were fed experimental diets for 16 weeks and grew from approximately 40 to 250 g, in 15 °C spring water. All tanks were fed the same percent biomass per day. Diets were isonitrogenous, and dietary energy varied with dietary lipid. Diet digestibility data and results of the experiment were used to construct N and P budgets for the fish fed the various diets. A reduction in dietary fish meal from 500 to 200 g kg–1 dry diet, corresponding to a reduction in dietary P from 14 to 8 g kg–1 dry diet, resulted in >50% reductions in both solid and dissolved P waste, but did not affect growth, feed efficiency ratio (FER) or sensory characteristics of rainbow trout. Increasing dietary lipid from 170 to 310 g kg–1 dry diet led to higher growth rate and FER, and lower total N waste relative to weight gain, but did not change protein retention. Increasing dietary lipid level increased deposition of lipid in whole bodies of rainbow trout, and resulted in discernible differences in sensory characteristics of trout fillets.  相似文献   

2.
A feeding trial was conducted to evaluate the effect of nucleotides supplementation to low‐fish meal feed on growth and fatty acid composition of rainbow trout. Six isonitrogenous (42% crude protein) and isolipidic (18% crude lipid) diets were formulated containing fish meal and plant ingredients as main protein sources. The control diet was a basal diet without supplementation of nucleotides, and five experimental diets were prepared by supplementing one of the five different nucleotides in the form of 5′‐monophosphate (0.15%), that is inosine (IMP), adenosine (AMP), guanosine (GMP), uridine (UMP) and cytidine (CMP) onto basal diet. Two hundred forty juvenile rainbow trout with an initial average body weight 9.8 g were randomly distributed into twelve aquaria. After 15 weeks of feeding period, growth performance and feed utilization of rainbow trout were not significantly different among dietary treatments. Dietary GMP, UMP and CMP tended to accumulate crude lipid in the muscle and whole fish body. Moreover, dietary GMP, UMP and CMP significantly increased hepatic 18:3n‐3 and long‐chain homologue 18:4n‐3 and 20:4n‐3 contents. Hepatic 18:2n‐6 content showed also increase in fish fed GMP, UMP and CMP diets, but decreased in long‐chain homologue 20:3n‐6 and 20:4n‐6 contents. Decrease in 20:4n‐6, 20:5n‐3 and 22:6n‐3 contents was also found in the muscle of fish fed IMP, GMP and CMP diets. The present study clearly showed that there was no positive effect of dietary nucleotides on growth of fish, but dietary nucleotides particularly GMP, UMP and CMP altered polyunsaturated fatty acid composition of rainbow trout.  相似文献   

3.
In the work to find replacement for fish meal in feed for fish, the inclusion of plant protein sources at high dietary level is an important issue. The present experiment was carried out to reveal how different feed ingredients affected the eating quality of the grown up fish with focus on nitrogen compounds as amino acids, taurine and anserine. Six experimental diets were fed to rainbow trout in triplicates for 90 d. All diets were composed to be equal in protein, lipid, energy and lysine. Three levels of a mixture of plant sources (full fat soy, extracted soy, soy protein concentrate, corn gluten) constituting 57.2%, 73.9% and 90.6% of total dietary protein were used. A small amount of fish meal was added in 5 diets constituting 9.4% of total protein. A fish hydrolysate that was high in free amino acids, taurine and anserine was tested at 16% and 32% dietary inclusion of total protein. Two other diets contained the same level of protein from the same hydrolysate that was ultra filtrated to remove low molecular weight compounds. Digestibility of taurine and anserine was found to be close to 99% for all groups, except for the group containing high level of plant sources. The levels of taurine in whole trout and fillets decreased during the feed experiment, but were about the same for all groups at the end of the feeding experiment and independent of dietary levels. The level of anserine in fish and fillets was equal from start to end of the experiment and independent of dietary inclusion. Taurine and anserine therefore seem to be homeostatic regulated in trout and independent on dietary levels. Amino acid content in fish and fillet was also equal for all groups and independent of protein sources used in the diets. The chemical composition showed higher lipid and dry matter levels in fish and fillet in fish that grew the fastest. In conclusion, plant protein sources may be included in diets for trout at high levels without affecting the eating quality as evaluated by amino acids, taurine and anserine levels.  相似文献   

4.
Recent studies with rainbow trout, Oncorhynchus mykiss, demonstrated that grain distiller's dried yeast (GDDY) at up to 12% inclusion was an effective dietary protein source when replacing fish meal. To examine the effectiveness of GDDY when replacing an increased variety of dietary protein sources, two feeding trials were conducted. In the first trial, six commercial‐type diets were formulated to contain 42% digestible protein and 20% crude lipid with GDDY included at 0, 6, 9, 12, 15, and 18% to replace all dietary protein sources except fish meal. In the second trial, four plant‐based diets with GDDY at 0, 9, 12, and 15% were examined. Experimental diets were fed twice daily, to apparent satiation, to three replicate tanks of fish/diet (initial weight = 22.3 ± 0.7 g) for 10 wk in a 15 C recirculating system. Results demonstrated excellent fish growth and the inclusion rate of GDDY did not negatively affect growth or feed conversion. No significant negative effects of GDDY on body indices or whole‐body proximate composition were observed. Based on these results, GDDY can be included in both commercial‐type diets and plant‐based diets for rainbow trout at up to 18 or 15%, respectively, without decreasing growth performance.  相似文献   

5.
Abstract.— Fish meal is one of the predominant sources of crude protein used in practical feeds for most cultured species. However, with overfishing and increasing demand for protein feedstuffs, new competitively priced sources of dietary protein are needed. A coextruded soybean meal-red blood cell (SBM-RBC) ingredient was evaluated as a source of crude protein for rainbow trout Oncorhynchus mykiss . The SBM-RBC ingredient was incorporated at either 0, 21, 42 or 63% of the dietary protein, replacing an isoni-trogenous amount of fish meal. All diets were fed for 8 wk to triplicate groups of juvenile rainbow trout (average initial weight 49.5 g) stocked into a recirculating system consisting of 48, 114-L aquaria. There were no significant differences in weight gain, feed conversion ratio, protein efficiency ratio, apparent crude protein digestibility, apparent gross energy digestibility, dress-out percentage, or fillet protein and fat concentrations in fish fed any of the experimental diets. Based on these data, extruded SBM-RBC appears to be a suitable ingredient in diets fed to rainbow trout.  相似文献   

6.
Three oilseed protein concentrates (soybean, canola, and sunflower) were evaluated to determine their potential, when supplemented with deficient essential amino acids, to partially or completely replace fish meal in diets fed to rainbow trout Oncorhynchus mykiss . Triplicate aquaria of juvenile trout (average weight of 12 g) were fed the experimental diets for 10 wk, at which time the average weight of the fish was approximately sixfold higher than the initial weight. Average fish weight gains on diets in which the protein component was 100% fish meal; 75% fish meal, 25% soybean protein concentrate; 50% fish meal, 50% soybean protein concentrate; and 75% fish meal, 25% sunflowerseed protein concentrate were not significantly different ( P < 0.05). The average weight of fish fed a commercial feed was significantly lower than that of fish fed the 100% fish meal diet, but not significantly different from fish fed the three other formulations mentioned above. Fish fed diets containing 50% fish meal, 50% canola protein concentrate; and 25% fish meal, 75% sunflowerseed protein concentrate had significantly lower average final weights than those of fish fed the other diets. Feed conversion ratio patterns among the dietary treatment groups reflected those of weight gain. Fish survival exceeded 95% on all diets. Apparent protein digestibility coefficients ranged from 79.5% (75% soybean protein concentrate, 25% canola protein concentrate) to 90.6% (100% soybean protein concentrate). The results of this study demonstrated that certain oilseed protein concentrates have good potential as protein sources in rainbow trout feeds when properly supplemented with essential amino acids.  相似文献   

7.
The aim of this trial was to compare the performance of rainbow trout fed diets including local or imported fish meal as the main protein sources, and to test the effect of reducing the fish meal content or including a fish protein hydrolysate in the diets. Two experimental diets were formulated to include 35% (diet 2) or 20% (diet 3) of a local processed whole fish meal; two other diets were formulated similar to diets 2 and 3 but with 5% fish protein hydrolysate replacing the same amount of fish meal (diets 4 and 5 respectively); a diet similar to diet 2, but including Norwegian fish meal, was used as a control (diet 1). The growth trial lasted 14 weeks and was carried out in floating net cages (325‐L capacity), with duplicate groups of 20 rainbow trout of an initial average weight of 58 g. The apparent digestibility coefficients (ADC) of the diets were evaluated in a separate laboratory trial. At the end of the growth trial, there were no significant differences in growth rate and protein efficiency ratio among groups. Feed conversion ratios were significantly better in groups fed diets 3, 4 and 5 than in the other groups. Nitrogen retention (% of N intake) was significantly higher in fish fed diets 4 and 5 than in those fed diet 2. There were no significant differences in energy retention (% of energy intake) among groups. At the end of the trial, there were no significant differences among groups in proximate composition of whole fish. The ADC of protein, energy and phosphorus of diets 1 and 2 were significantly lower than those of diets 3 and 5. It was concluded that, under the experimental conditions tested, performance of rainbow trout fed practical diets including good quality local processed fish meal is similar to that of fish fed diets including Norwegian fish meal. A reduction in the fish meal from 35% to 20% of the diet or the inclusion of a fish protein hydrolysate had no negative effects on growth performance and improved feed utilization.  相似文献   

8.
《水生生物资源》1998,11(4):239-246
High energy extruded diets were formulated to contain the same level of protein supplied either by soy protein concentrate (SPC) or fish meal. Three experiments were performed in order to measure voluntary feed intake and feed waste, faecal losses and soluble losses of nitrogen and phosphorus in rainbow trout (average body weight: 100 g). Voluntary feed intake and growth performance of fish fed with demand feeders were not different when diets contained 0, 50 or 75 % SPC instead of fish meal. Total replacement of fish meal by SPC led to a significant decrease in feed intake and resulted in poor growth. This was partly due to methionine deficiency in the SPC based diet. With the addition of crystalline DL-methionine in the diets, an improvement of feed intake and growth performance was apparent. Protein digestibility was high, regardless of the protein source. Excretion of ammonia and urea increased with the level of SPC in the diet. Nitrogen losses decreased when methionine was added to the diet containing only SPC as a protein source. Availability of phosphorus increased with the level of SPC in the diets. Daily soluble losses were not affected by the dietary treatments but the pattern of phosphorus excretion after feed intake was modified. The rise in soluble phosphorus in water occurred later when fish were fed diets with soy protein whatever the dietary level of soy protein concentrate.  相似文献   

9.
A feeding trial was conducted to investigate the effects of the replacement of dietary fish meal and fish oil with oilseed meals (soybean or canola) and canola oil on growth, nutrient utilization, body composition, diet digestibility and hematological parameters of rainbow trout Oncorhynchus mykiss. Seven diets were used; the control diet (designated FM) contained fish meal and fish oil as the main protein and lipid sources. For the experimental diets, 40% of fish meal protein was substituted with soybean meal, canola meal or a soybean/canola meal mixture, and these diets (designated SM, CM and SCM, respectively) contained fish oil as the lipid source. Three additional diets (SM?+?CO, CM?+?CO and SCM?+?CO) were formulated with the same vegetable protein meals but with fish oil replaced by canola oil. Fish were fed twice daily to apparent satiation for 11?weeks. The growth of fish fed the CM?+?CO diet was significantly lower than that of fish fed the FM, SCM, SM?+?CO and SCM?+?CO diets. The feed conversion ratio (FCR) was significantly better in fish fed the FM and SCM?+?CO diets than in fish fed the CM and CM?+?CO diets. Furthermore, feed intake was significantly lower for fish fed the CM?+?CO diet than in fish fed the SCM diet, and lipid digestibility of the CM?+?CO diet was significantly lower than that of all other diets. No significant differences of body composition were observed. Circulating leukocyte levels, leukocyte ratios and serum lysozyme activity remained unaffected by dietary treatment. However, it was observed that fish fed the CM?+?CO diet displayed hematocrit levels significantly lower (P?<?0.05) than that of fish fed the other diets. The results indicate that when diets contain either fish oil or canola oil, canola meal and soybean meal can be incorporated into rainbow trout feeds at a combined 32% inclusion level (replacing 40% of fish meal protein) without inducing significant negative effects on growth, nutrient utilization or health.  相似文献   

10.
Maca tuber meal is used in fish diet formulations in Andean trout culture and knowledge of its effects on fish growth is paramount to healthy human food production. In the first experiment with rainbow trout alevins (0.096±0.002 g), starter diets were offered from first feeding until 15 weeks. We formulated high protein content (～60%) semi‐purified starter diets supplemented with 0%, 5%, 10%, or 15% maca tuber meal (control, M‐5, M‐10, and M‐15 respectively). The second feeding trial was conducted with juveniles (1.56±0.02 g) fed one of three diets (control, M‐15, and commercial) for 8 weeks. In the first experiment, fish fed M‐10 and M‐15 diets exhibited significantly higher growth rates than the other dietary groups. Survival was significantly improved in the groups fed diets supplemented with maca tuber meal (60.0–69.2%) in comparison with the group fed a control diet (21.7%). The second experiment showed a higher growth rate in the M‐15 group compared with the control and a commercial diet fed group. Leucocyte numbers were increased by dietary supplementation of maca tuber meal. The findings of the present study suggest that a maca tuber meal inclusion at least 5% improves growth rate, feed utilization, immunity by increased leucocyte number, and survival of rainbow trout alevins and juveniles.  相似文献   

11.
The effect of replacing fish meal with soybean meal (SBM) pretreated with phytase on feeds of juvenile rainbow trout was evaluated in a 90-day feeding trial. The rainbow trout (initial body weight, 4.01 ± 0.02 g) were fed five isonitrogenous (crude protein, 44.97%) and isolipidic (crude lipid, 13.42%) feeds. Diets were formulated to contain phytase-pretreated SBM replacing 0, 20, 40, 60 and 80% of fish meal protein, respectively. The results showed that there was no significant difference in weight gain (WG) among fish fed S0, S20, S40 and S60 diets; however, a significant reduction of this variable occurred when 80% of fish meal protein was replaced by phytase-treated SBM (P < 0.05). Similarly, specific growth rate and protein efficiency ratio had a similar trend with WG. Apparent digestibility coefficient (ADC) of protein and lipid in the S80 diet was significantly lower than that of the other diets, and the ADC of phosphorus significantly increased with the increase of dietary phytase-treated SBM level. No significant differences among treatments were detected for moisture, protein, lipid and ash content in whole body and muscle samples. Nitrogen and phosphorus excretion indicated that fish meal replacement by phytase-treated SBM led to an increase in nitrogen excretion, but led to a reduction in total phosphorus excretion. The results of the present study show that 60% of fish meal could be replaced by phytase-treated SBM in diets of juvenile rainbow trout without compromising weight gain or feed efficiency. A quadratic equation according to regression analysis of weight gain against dietary phytase-treated SBM level indicated that the optimal level of dietary phytase-treated SBM replacement for maximum growth was 26.90%.  相似文献   

12.
ABSTRACT:   Two experiments were conducted to evaluate feed quality and body phosphorus (P) and nitrogen (N) retention by rainbow trout fed test diets with low amounts of fish meal content and alternative low-P protein sources. A fish meal (FM) diet was used as control. Fish weighing 2.0 g and 134.7 g on average were reared with the experimental diets for 30 weeks and 15 weeks, respectively. The experimental diets had a good growth rate and feed utilization. In the first experiment the P retention was higher in the group of fish fed test diets (56 and 69%) compared to the FM-based diet (36%); N retention rates were similar for all groups. In the second experiment, fish were fed the test diet that had the best P retention in the earlier experiment. The P retention was lower than the values obtained in the first experiment (smaller fish), but still higher in the group of fish fed the low FM diet in comparison with the control group (36.0% and 22.2%, respectively). This represents a P loading into the water of 5.9 kg/t and 12.8 kg/t production for the test and the control diet, respectively. Therefore, low-P-loading diets for rainbow trout can be developed through the appropriate combination of alternative protein sources.  相似文献   

13.
Preliminary studies were conducted to determine if several feed supplements with the potential to improve dietary mineral availabilities in fish meal had any measurable effect in fish feeds. In the first study with rainbow trout, 11 supplements were tested: citric acid; sodium citrate; potassium chloride; sodium chloride; histamine dihydrochloride; EDTA disodium salt; sodium bicarbonate; a mixture of amino acids; ascorbic acid; a mixture of inositol and choline; and cholecalciferol. Apparent availability of calcium, phosphorus, magnesium, sodium, iron, manganese and strontium in fish meal-based diets was determined using both yttrium oxide (Y2O3) and chromium oxide (Cr2O3) as inert dietary markers. Apparent availability was expressed as the fractional net absorption (%) of minerals from diets. After a 7-day acclimation period with test diets, fecal samples were collected for five consecutive days using passive collection systems. Apparent availability of calcium, phosphorus, magnesium, iron, manganese and strontium was increased by citric acid supplementation. Apparent availability of manganese also was increased by EDTA and sodium citrate. The other supplements had no measurable effect on the apparent availability of minerals in fish meal. In the second study, the effect of supplemental citric acid was further investigated using monogastric (rainbow trout) and agastric fish (goldfish). Fish were fed for 5 weeks (rainbow trout) or 3 weeks (goldfish) with fish meal-based diets containing either 0% (control), 2% or 5% citric acid on a dry basis. Feces were collected by settling and by stripping. Apparent availabilities of calcium and phosphorus were greatly affected by citric acid supplementation in rainbow trout but not in goldfish. Phosphorus levels in feces of fish fed a diet with 5% citric acid were approximately half of that of fish fed the control diet (0% citric acid) in the rainbow trout trial. This pattern was consistent during the 5-week feeding trial. A dietary supplement of citric acid as high as 5% did not reduce feed intake or appetite of rainbow trout. Conversely, this level of dietary acidification led to a marked reduction of feed intake in goldfish. Dietary supplementation of citric acid at 2% level did not reduce feed intake of goldfish; however, this level of dietary acidification had little effect on the apparent availability of major minerals in fish meal-based diet. Levels of non-fecal excretion of calcium and phosphorus, inorganic phosphorus in urine, and citric acid in feces were increased in rainbow trout fed 5% citric acid. The pH values of the feces and urine were decreased in rainbow trout fed citric acid. Plasma bicarbonate, plasma calcium and phosphorus, and blood pH of rainbow trout tended to increase by a 5% dietary supplementation of citric acid. The soluble inorganic phosphorus content increased in the diets and decreased in the feces of rainbow trout by supplementing the diet with 5% citric acid. Feces samples of rainbow trout collected by stripping provided similar availability values to data collected by settling for most elements except sodium, which had negative values in all dietary treatments.  相似文献   

14.
Rainbow trout (Salmo gairdneri) with an initial average weight of 1.8 g were fed eight experimental diets with 26 and 35% protein and varying amounts of lipid for 112 days. All experimental diets contained 10% fish meal (the only source of animal protein), as compared to a control diet with 35% fish meal. The energy content of the diet was the most important factor in determining growth rate. The percentage of dietary lipid was the dominant factor in determining the body composition of rainbow trout. Increased amounts of dietary lipid resulted in fish with increased amounts of whole-body fat and reduced amounts of whole-body protein and moisture. Body composition was more closely a function of nutritional history than of fish size. Protein retention and energy retention were negatively associated with the percentage of digestible protein in the diet. Mortality rates did not differ significantly among the groups tested; the general health of all fish examined was good.  相似文献   

15.
A feeding trial was conducted with juvenile rainbow trout (15–16 g initial weight) to assess the effects of including single‐cell protein (SCP) produced from Methylobacterium extorquens in trout feeds. Three isonitrogenous and isoenergetic diets were produced: a control diet and two experimental diets containing 5% or 10% bacterial protein meal replacing soybean meal. Triplicate tanks, each containing 35 fish, were fed each diet to apparent satiation in a constant‐temperature (15°C), flow‐through tank system for 12 weeks. No statistically significant differences in final fish weight or other fish growth parameters were observed. Similarly, feed efficiency parameters showed no significant differences among groups. Nutrient retention indices (protein, fat, energy) were relatively high and similar among fish in each dietary treatment group, as were whole body proximate compositions. Fish survival was high, with a small but statistically significant increase for the 10% SCP diet. Overall, results demonstrate that SCP from M. extorquens is a safe and effective alternative protein for rainbow trout diets at the low inclusion levels tested. Slightly lower weight gain in fish fed the 10% SCP diet was largely due to lower feed intake, suggesting that adding palatability‐enhancing ingredients to feeds may allow higher levels of M. extorquens SCP to be used without compromising fish growth.  相似文献   

16.
Abstract— Fisheries by-catch and by-product meals are portrayed as ingredients having a great potential as ingredients in aquaculture feeds. The present study was designed to evaluate the nutritional value of shrimp by-catch meal, shrimp processing waste meal, and two fish meals made from Pacific whiting (meal with and without solubles) for rainbow trout by determining apparent digestibilityof these ingredients and conducting a 12-wk feeding trial with juvenile fish (average initial weight 20 g/fish). Apparent digestibility coefficients (ADCs) for protein in diets containing by-catch and processing by-products were 76% for shrimp by-catch meal, 79% for shrimp processing waste meal, 88% for Pacific whiting meal without solubles, and 92% for Pacific whiting meal with solubles. ADCs for lipid were higher than 94% for all the diets. ADCs for energy were 57% for shrimp by-catch meal, 73% for shrimp processing waste meal, 70% for Pacific whiting meal without solubles, and 73% for Pacific whiting meal with solubles. Growth performance was significantly affected by dietary protein source. Fish fed the shrimp by-catch meal diet had weight gain and feed conversion ratios similar to that of fish fed the control diet with anchovy fish meal. Fish fed diets containing shrimp processing waste and Pacific whiting meal with solubles had significantly lower weight gain and higher feed conversion ratios than the control diet. Growth was significantly lower in fish fed the Pacific whiting meal diet compared to fish fed the anchovy fish meal. The lower growth of fish fed diets containing Pacific whiting meal appeared to be a result of lower feed intake, indicating perhaps a lower palatability of this ingredient. Additional research addressing processing methods, nutritional manipulations, and palatability enhancement is needed to improve potential of some fisheries byproduct meals as ingredients in the diets of rainbow trout.  相似文献   

17.
Solid waste recovered from clam processing wash water was evaluated for its utilization as a replacement protein for fish meal. Three diets, diets 1 and 2 formulated to simulate the Oregon Moist Pellet (OMP) and diet 3 (Rangen), were fed to rainbow trout (Salmo gairdneri) for eight weeks. The effects of the clam waste meal on fish growth, food conversion, carcass composition and whole body fatty acid content were determined. The clam waste diet supported maximum growth and food conversion. Carcass analysis of moisture, protein and lipid contents were similar among the moist feeds. The dietary levels of 20:5w3 + 22:6w3 and total polyunsaturated fatty acids (PUFAs) were significantly higher in the clam waste diet pellet.  相似文献   

18.
The effects of protein source and nutrient density on growth efficiency, nutrient digestibility and plasma amino acid concentrations of rainbow trout were evaluated. A 3 by 2 factorial treatment design with three protein sources, fish meal–barley (F–B), plant concentrates (PC) and plant meals (PM), and two nutrient densities were used. A commercial reference diet was also fed. Triplicate tanks of 30 fish (initial wt. 28 g) were fed each diet, and the final weight averaged 240 g fish−1. Protein source and nutrient density affected feed intake, weight gain and feed conversion ratio. Weight gain of trout fed the PC and PM diets was approximately 10% less than fish fed the F–B diets. Protein retention was affected by protein source, but not nutrient density, and was the highest for the fish fed diets containing fish meal and the lowest for the fish fed PM diets. Apparent digestibility coefficients and apparent amino acid availabilities of the diets corresponded with differences in weight gain. This study provides further evidence that growth rates of trout fed fish meal‐free diets, using conventional and concentrated plant protein ingredients, are good but some limitation to growth exists in the fish meal‐free diets.  相似文献   

19.
A 10-week feeding experiment was conducted to determine the proper dietary protein source for optimal growth performance of juvenile snails, Semisulcospira coreana. Sixteen isonitrogenous (31% crude protein) and isocaloric (4.2 kcal/g DM) experimental diets (designated as FM, F-FM, SBM, F-SBM, WF, F-WF, SSM, F-SSM, SCR, F-SCR, UP, F-UP, FWP, F-FWP, MIX and F-MIX) were formulated to contain 41% fish meal, 42% fermented fish meal, 59% soybean meal, 55% fermented soybean meal, 55% wheat flour with 26% fish meal, 55% fermented wheat flour with 29% fish meal, 50% sesame seed meal with 10% fish meal, 50% fermented sesame seed meal with 11% fish meal, 55% soya-curd residue or fermented soya curd residue with 25% fish meal, 50% Undaria powder or fermented Undaria powder with 24% fish meal, 50% freshwater plant with 29% fish meal, 50% fermented freshwater plant with 28% fish meal, a mixture of 8% soybean meal, 10% wheat flour, 8% sesame seed meal, 8% soya-curd residue, 8% Undaria powder and 8% freshwater plant with 17% fish meal, and 50% the fermented mixture with 16% fish meal, respectively, as dietary protein sources. Juvenile snails (average weight, 32 ± 0.7 mg) were randomly distributed in forty-eight 25-L aquaria (16 L water each) in a flow-through system at a density of 130 snails per aquarium. Three replicate groups of snails were fed one of the experimental diets ad libitum once per day for 10 weeks. At the end of the feeding experiment, survival of snails was above 98% and not significantly different among the dietary treatments. The best final body weight was observed in snails fed the SBM and WF diets. There were no significant differences in final body weight of snails fed the F-SBM, WF, F-WF and MIX diets, but the value was higher than that of snails fed the FM, F-FM, FWP and F-FWP diets. The lowest value was observed in snails fed the SSM, F-SSM, SCR and F-SCR diets. Whole body protein and lipid contents of snails varied with dietary protein sources. Amino acid composition of whole body was altered by dietary protein sources. The results of the present study indicate that dietary protein sources significantly influence proximate and amino acid composition, and growth performance of snails. Fermentation with ferminpan instant brown yeast does not improve nutritional quality of the protein sources, and soybean meal and wheat flour in combination with fish meal could be potential protein sources in feeds for juvenile snails.  相似文献   

20.
The potential of rapeseed protein concentrate as fish meal alternative in diets for rainbow trout (initial average weight 37.8?±?1.4?g) was evaluated. Nine experimental tanks of a freshwater flow-through system were stocked with 12 fish each. Triplicate groups of fish received isonitrogenous (47.9?±?0.5% CP) and isoenergetic (22.4?±?0.2?kJ?g?1) experimental diets with 0, 66 and 100% of fish meal substituted with rapeseed protein concentrate (71.2% CP), thereby providing 0, 29 and 43% of dietary protein. As the amino acid profile of rapeseed protein concentrate was comparable to fish meal, there was no need to supplement experimental diets with synthetic amino acids. At the end of the 84?days of feeding period, fish growth performance, feed intake and feed efficiencies were not compromised, when 100% of fish meal in the control diet was replaced with rapeseed protein concentrate, revealing a SGR of 1.19 or 1.10, a FCR of 1.09 or 1.18 and a feed intake of 78.5 or 74.7?g in fish fed on the control diet or fed the diet devoid of fish meal, respectively. Intestinal morphology did not reveal any histological abnormalities in all dietary groups. Blood parameters including haematocrit and haemoglobin as well as glucose, triglycerides and total protein in the plasma were not different between treatment groups. Thus, the rapeseed protein concentrate tested here has great potential as an alternative to fish meal in rainbow trout diets.  相似文献   

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