Tissue composition,blood biochemistry and histology of digestive organs in Senegalese sole (Solea senegalensis) juveniles fed diets containing different plant protein ingredients

The aim of this study was to determine the impact of diets with different plant protein ingredients on proximate composition, tissue metabolites and tissue fatty acid composition, as well as hepatic and intestinal histological modifications in Senegalese sole (Solea senegalensis). Fish (21.5 ± 2.8 g body weight) were fed six isonitrogenous and isoenergetic diets during 11 weeks. A control diet containing fish meal as the main protein source was compared with five experimental diets replacing 30% fish meal protein by different plant protein sources: soybean meal (SBM), soybean protein concentrate (SPC), soybean protein isolate (SPI), wheat gluten meal (WGM) or pea protein concentrate (PPC). The inclusion of different plant protein did not significantly affect growth and proximate composition of fish. The hepatosomatic index was not significantly different to the control group; however, utilization of WGM significantly increased hepatocyte size. Plasma protein values and muscle triglycerides were influenced by the inclusion of SBM and WGM in the diets respectively. Feeding fish on SBM, WGM and PPC diets significantly enhanced n‐6 fatty acid levels in muscle, particularly linoleic acid. None of the plant protein ingredient used in the diets decreased arachidonic, eicosapentaenoic as well as docosahexaenoic acid values in liver and muscle. Overall, histological studies did not reveal the existence of any intestinal alterations induced by the inclusion of different plant proteins. Despite moderate changes produced by SBM, SPC and WGM, inclusion of dietary plant protein ingredients has no major impact on growth, tissue and blood biochemistry, fatty acid profile and gut integrity of Senegalese sole juveniles.     

Feed intake and growth performance of Senegalese sole (Solea senegalensis Kaup, 1858) fed diets with partial replacement of fish meal with plant proteins

To be able to study nutrient requirement and utilization in any species, a diet supporting normal feed intake and growth equally well as a traditional fish meal‐based diet is needed. Additionally the formulation of the diet should allow low levels of the nutrient under study. When studying the amino acid metabolism and requirements, one cannot rely on the fish meal‐based diets as fish meal are nicely balanced according to requirements. Therefore the current study aimed to develop a plant protein‐based diet (with low fish meal inclusion) to be used in the nutritional studies of Senegalese sole juveniles supporting feed intake and growth close to that obtained in a fish meal‐based control feed. Two experiments were conducted to evaluate whether Senegalese sole juveniles would accept and utilize diets containing high plant protein inclusion. For testing the acceptance of high plant protein inclusion, two diets were formulated: a reference diet that contained fish meal as the main protein source (450 g kg^?1 dry matter) whereas in the test diet, fish meal was substituted by a mixture of plant ingredients (soybean meal, corn and wheat gluten) with l ‐lysine supplementation. In order to improve the palatability, 50 g kg^?1 squid meal was added to both diets. The indispensable amino acids (IAA) profile of the test diet was made similar to the control diet by adding crystalline amino acids. Further, automatic feeders were used to improve the feed intake. Fish (24 g initial body weight) were fed the diets for a period of 4 weeks. As fish accepted both diets equally well, a second study was undertaken to test the growth performance. Fish (6 g initial BW) were fed the diets for a period of 12 weeks. The use of automatic feeders to deliver the feed and the addition of both squid and balancing the indispensable amino acids resulted in growth performance and accretion not differing from the fish meal fed control. It can be concluded that juvenile Senegalese sole are able to grow and utilize high plant‐protein diets when both diet composition and feeding regime are adequate for this species.     

Amino Acid Availability of Four Practical Feed Ingredients Fed to Striped Bass Morone saxatilis

Four dietary protein sources were bio-assayed for amino acid availability, as estimated by true digestibility, when fed to striped bass Morone saxatilis . Diets were formulated to contain either herring fish meal, soybean meal, corn gluten meal or peanut meal as the sole source of dietary protein. A fifth diet, containing no protein, was fed to estimate the level of endogenous amino acids for calculation of true digestibility. The five dietary treatments were randomly assigned to ten tanks of striped bass having an average weight of 150 g per fish. All fish received the assigned diet fed at a rate 1.5% of the biomass per day for a period of 10 d. Fecal samples were collected from anesthetized fish by gentle, manual stripping of the lower digestive tract. Diets and feces were analyzed for dry matter, chromium, nitrogen and amino acid concentrations. There were no statistical differences (P > 0.05) among the protein sources for apparent dry matter digestibility or availability of arginine, threonine, valine and nonessential amino acids with the exception of cysteine. Corn gluten meal had a significantly lower availability coefficient for lysine, and peanut meal had significantly lower availability coefficients for histidine, isoleucine, leucine, and lysine when compared to herring fish meal and soybean meal. Statistically there were no differences between soybean meal and herring fish meal for any nutrient tested. These data suggest that in terms of amino acid availability and overall protein quality, soybean meal could be used to spare herring fish meal in striped bass diets, with corn gluten meal being equally as useful when supplemented with lysine or complemented with other proteins.     

Effect of replacing fishmeal and oil with simple or complex mixtures of vegetable ingredients in diets fed to Nile tilapia (Oreochromis niloticus)

The effect of replacing fishmeal with simple or complex mixtures of plant proteins in tilapia diets was examined. Diet formulations were arranged in a 2 × 4 factorial design with two types of plant protein mixtures used to replace fishmeal (simple: soybean meal and maize gluten meal or complex: soybean meal, maize gluten meal, dehulled flax, pea protein concentrate and canola protein concentrate) and four levels of protein originating from fishmeal (1000 g kg^?1, 670 g kg^?1, 330 g kg^?1 and 0 g kg^?1). Diets contained equal digestible protein (380 g kg^?1) and digestible energy (17.6 MJ kg^?1). The average daily gains, specific growth rates and feed efficiencies of fish fed diets with 0 g kg^?1 fishmeal were significantly lower than fish fed diets with the 330 g kg^?1, 670 g kg^?1 or 1000 g kg^?1 fishmeal levels. Fish fed the complex diets had significantly higher average daily gains, specific growth rates, feed : gain ratios and protein efficiency ratios than those fed the simple diets. Intestinal villus length decreased with decreasing levels of fishmeal and increased with increased diet complexity but the effects were not significant. Replacement of fishmeal with a complex mixture of plant ingredients may allow a greater replacement of fishmeal in diets fed to Nile tilapia.     

Soy protein concentrate as a protein source for Senegalese sole (Solea senegalensis Kaup 1858) diets: effects on growth and amino acid metabolism of postlarvae

The objective of this work was to evaluate the effect of a dietary amino acid imbalance, originating from the use of a soy protein concentrate (SPC) as the major protein source, on the growth performance and amino acid metabolism of Senegalese sole (Solea senegalensis) postlarvae. Senegalese sole (85.6±24.6 mg wet weight) were fed one of two experimental diets: one based on fish meal (FM) and another based on SPC. Diets were isonitrogenous (around 56% crude protein) and isoenergetic. Diet acceptability was very good and the growth rate was 6.9% day^?1 for sole eating the FM diet and 6.0% day^?1 for sole eating the SPC diet. Mass‐specific ammonia excretion and the activities of selected amino acid metabolic enzymes (ALAT, ASAT and GDH) did not present significant differences between treatments, although this may have been due to the high variability found for these parameters in the SPC treatment. This variability may suggest different capacities of individual fish to adapt to the possible methionine dietary deficiency. The utilization of amino acids as a substrate for lipogenesis does not seem to be affected by the dietary protein source, since NAPDH‐generating enzymes (G6PD and ME) had similar activities in both treatments. Amino acid metabolism in Senegalese sole postlarvae seems to be slightly affected by the dietary protein source. Nevertheless, the changes induced by the SPC diet do not seem to impair growth, at least at the high dietary protein level used in this experiment.     

复合植物蛋白源替代鱼粉对半滑舌鳎生长、生理生化指标和肠组织结构的影响

实验以6种植物蛋白源(谷朊粉、大豆浓缩蛋白、豆粕、棉籽蛋白、花生粕和玉米蛋白粉)配比成复合植物蛋白源,以其替代半滑舌鳎(Cynoglossus semilaevis Güntuer)饲料鱼粉蛋白,共设计9种实验饲料,分别为全鱼粉组(FM)以及替代鱼粉蛋白水平分别为20%(PP20)、30%(PP30)、40%(PP40I、PP40II、PP40III和PP40IV)、60%(PP60)和80%(PP80)组,旨在最大限度替代舌鳎饲料中鱼粉蛋白,而不影响鱼体生长、生理生化指标和肠组织结构形态。以初重为(255.21±0.79)g的半滑舌鳎为研究对象,在室内流水系统中进行9周摄食生长实验,每个处理设3个重复,每桶放养15尾鱼。结果表明,各处理组实验鱼的增重率、特定生长率、饲料效率、摄食量、蛋白质效率、蛋白质沉积率和成活率均无显著性差异(P0.05);复合植物蛋白源替代鱼粉后对鱼体粗蛋白和水分含量以及血浆甘油三酯含量无显著影响(P0.05);但当复合植物蛋白源替代高比例鱼粉蛋白时,显著降低鱼体粗脂肪和血浆胆固醇含量(P0.05),且肝体比随植物蛋白源的添加而降低,PP30组显著低于FM组(P0.05);另外,4个PP40组相比,PP40III组的脏体比显著高于其他3个40%替代组。复合植物蛋白源替代鱼粉比例不超过60%时,对半滑舌鳎后肠组织结构无损伤或仅有轻微损伤,而PP80组后肠绒毛出现严重损伤现象。以上结果表明,复合植物蛋白源可以有效替代80%的鱼粉蛋白而不影响半滑舌鳎的生长性能和饲料利用率,但综合考虑鱼体生理生化和肠道组织结构指标,认为在半滑舌鳎饲料中复合植物蛋白源替代鱼粉的比例不宜超过60%。     

Effects of varying dietary compositions using common feed ingredients on growth and feed efficiency of pond‐raised channel catfish Ictalurus punctatus (Rafinesque)

Two experiments were conducted to evaluate various ingredient combinations in a 28% or 32% protein diet for optimum performance of channel catfish Ictalurus punctatus. All diets contained soybean meal and corn, but with or without cottonseed meal, wheat middlings or fish meal (FM). Channel catfish fingerlings were stocked into 0.04 ha earthen ponds at 18 530 fish ha^?1. Fish were fed one of eight diets once daily to apparent satiation for two growing seasons. Results demonstrated that the dietary ingredient composition used had significant effects on fish performance, but magnitude of differences was relatively small. Overall, diets containing FM resulted in greater weight gain (Experiments 1 and 2) and lower feed conversion ratio (Experiment 1) than fish fed all‐plant diets. However, certain combinations of plant ingredients provided the similar fish growth as some diets containing FM. There were no significant differences in weight gain between fish fed soybean meal–corn or soybean meal–corn–wheat middlings‐based diets with cottonseed meal or FM. The use of wheat middlings in the diet had no significant effects on fish production characteristics.     

Apparent protein and energy digestibility of common and alternative feed ingredients by Atlantic cod, Gadus morhua (Linnaeus, 1758)

Studies were conducted with Atlantic cod, Gadus morhua (L.), to determine the apparent digestibility coefficients (ADCs) of protein and energy and the digestible energy (DE) content in feed ingredients widely available in Canada. We also tested the assumption of “independency” used in digestibility studies. The feed ingredients included two fish meals (herring, anchovy), three crustacean by-product meals (whole krill, crab, shrimp), two animal by-product meals (poultry by-product, hydrolyzed feather), six oilseed meals (soybean, soy protein concentrate, soy protein isolate, canola, canola protein concentrate, flaxseed), two pulse meals (white lupin, pea protein concentrate) and two cereal grain meals (corn gluten, wheat gluten). Protein ADCs were high for wheat gluten meal (99.9%), soy protein concentrate (98.6%), soy protein isolate (97.4%), whole krill meal (96.3%), herring meal (93.3%), soybean meal (92.3%), anchovy meal (92.2%), pea protein concentrate (89.8%), white lupin meal (89.7%), crab meal (89.4%), canola protein concentrate (88.8%) and corn gluten meal (86.3%); mid-range for poultry by-product meal (80.2%) and canola meal (76.0%); and low for shrimp meal (66.7%), hydrolyzed feather meal (62.4%) and flaxseed meal (50.2-55.0%). Energy ADC was high for whole krill meal (96.3%), wheat gluten meal (95.4%), soy protein concentrate (94.9%), herring meal (92.8%), soy protein isolate (92.1%), soybean meal (88.1%) and anchovy meal (86.4%); mid-range for canola protein concentrate (83.3%), corn gluten meal (82.7%), crab meal (82.4%), pea protein concentrate (76.7%) and white lupin meal (75.3%); and low for poultry by-product meal (71.0%), canola meal (60.6%), hydrolyzed feather meal (58.9%), shrimp meal (41.4%) and flaxseed meal (21.2-37.4%). From the protein ADC data, results clearly showed that the basal diet and test feed ingredients were digested independently of one another in nearly all cases, the only exceptions being for those diets containing test ingredients of very high (> 99%, wheat gluten) or very low (< 67%, hydrolyzed feather and flaxseed) protein ADCs. In the case of DE, the basal diet and test feed ingredients were digested independently in all test diets without exception.     

Fishmeal can be totally replaced by plant protein blend at two protein levels in diets of juvenile Siberian sturgeon,Acipenser baerii Brandt

An 8‐week growth trial was conducted to evaluate the effects of a plant protein blend (PPB, comprised of soybean meal and wheat gluten meal) as fishmeal (FM) substitute on growth, nitrogen (N) and phosphorus (P) balance in Siberian sturgeon, Acipenser baerii Brandt. Two control diets were formulated to contain two protein levels (400 and 360 g kg^?1). At each protein level, FM was totally replaced by PPB with supplement of crystalline essential amino acids and mono‐calcium phosphate. Growth performance was not affected by dietary protein sources and protein levels. Fish fed the low‐protein diets had higher FI than that of the high protein groups, while fish fed the FM‐based diets had higher FI than that of fish fed the PPB‐based diets. N/P intake of fish showed linear relationship with total N/P loss. The productive P value was significantly affected by dietary protein sources, but no significant effects were shown on productive N value. The results suggest that Siberian sturgeon fed total plant‐based diets with balance of EAA could maintain normal growth performance and reduce total P excretion both at 360 and 400 g kg^?1 protein levels.     

The Effects of Substituting Selected Oilseed Protein Concentrates for Fish Meal in Rainbow Trout Oncorhynchus mykiss Diets

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.     

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

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

Assessment of the effect of plant inhibitors on digestive proteases of nile tilapia using in vitro assays

This study was conducted to evaluate the effect that feeding on differently treated soybean meals may have on digestive protease activity of the Nile tilapia (Oreochromis niloticus). Untreated full fat soybean (USB), heated fullfat soybean (HSB), soaked fullfat soybean (SSB) and commercial defatted soybean meal (DSB) totally replaced fish meal (FM) in test diets (30% crude protein) fed to fish juveniles (mixed sexes) for 30 days. After this period, total activity of digestive proteases was determined in each group and the ability of such proteases to hydrolyse the different protein sources and formulated feeds was tested in vitro. Significant differences were observed between treatments, with lower values obtained for fish fed on USB, suggesting a modification in the composition of secreted proteases. In addition, an inhibitory effect produced by wheat bran included in the test diets on protease activity of fish was also shown. The usefulness of using in vitro assays for a preliminary assessment of the nutritive value of aquafeed ingredients is discussed.     

Senegalese sole juveniles (Solea senegalensis Kaup, 1858) grow equally well on diets devoid of fish meal provided the dietary amino acids are balanced

A growth trial was conducted with the aim of developing a practical, environmentally sustainable and cost-effective plant-protein-based diet for Senegalese sole juveniles without compromising growth or protein deposition. A reference diet contained fish meal as the main protein source (F45, containing 37% fish meal and 45% of the dietary protein being from marine sources) and four plant-protein diets either containing 5% (F15) or no fishmeal (F5). The F15 diet also contained 5% hydrolysed protein (CPSP) and 5% squid meal while the F5 contained 2% CPSP and 3% squid meal. The rest of the protein derived from a blend of soybean meal, corn and wheat gluten. Thus, the plant-protein fraction in these test diets ranged from 70–80%. The plant-based diets were supplemented either with a mixture of all indispensable amino acids (IAA) (F15 + IAA, F5 + IAA) or only with lysine (F15 + Lys, F5 + Lys). Triplicate groups of 18 fish of 9.5 g were fed by automatic feeders that distributed 8 meals over 24 h, for a period of 12 weeks.At the end of the experiment mean body weight more than tripled in all treatments (32.8 to 42.7 g). Sole fed with either F15 + Lys (33.3 g) or F5 + Lys (32.8 g) grew significantly less than all the other treatments. Protein productive value (PPV) was significantly lower in sole fed with F5 + Lys (0.30) than in all other treatments (0.34 to 0.37) while F5 + Lys (0.23) energy productive value (EPV) just differed significantly from fish fed with F45 (0.38). Moreover, protein gain (P gain) was significantly higher in sole fed with diet supplemented with all IAA (F15 + IAA and F5 + IAA) than those fed with diet with only lysine added (F15 + Lys and F5 + Lys) and a strong positive correlation between P gain and methionine (Met) intake was found (P = 0.00002).Dietary fish meal protein can be totally replaced by a mixture of plant-protein sources without any adverse effects on growth, feed or protein utilization provided the dietary amino acids are balanced. The test diet F5 + IAA seems a good alternative to use in Senegalese sole production when the main objective is to substitute an increasingly scarce ingredient – fish meal – without compromising fish performance. Moreover, for large-scale production feeds the F15 + Lys putatively supplemented with Met, Thr and Arg would be recommended.     

Dietary plant protein utilization in Atlantic cod, Gadus morhua L.

The present trials aimed to investigate the effects of replacing fish meal with plant proteins in diets for cod, using a regression design where fish meal constituted the control. The plant protein diets were formulated to meet the amino acid requirements according to NRC (1993) and contained corn gluten meal, soybean meal, a mixture of these, or a mixture of wheat gluten meal and soybean concentrate. The plant protein fraction constituted up to 440 g kg⁻¹ of the extruded diet. Two feeding experiments were conducted, one at high (11 °C) and one at low (6.5 °C) temperature. High growth and feed utilization were obtained in all diet groups at both temperatures. However, only in Exp.1 (11 °C), growth and feed utilization were linearly reduced by increases in dietary soybean and corn gluten meal, while no such effect was detected in Exp.2 (6.5 °C). Reductions in protein retention were seen at both temperatures with use of all evaluated plant protein sources. Due to large amounts of plant protein ingredients in diet, differences in diet amino acid composition were seen. These were partly reflected in the muscle free amino acid pool. Dietary plant ingredients did not affect whole body, liver or muscle proximate compositions, or liver indices. In both experiments, blood parameters were within the range of earlier reported normal values and indicated, together with low mortality, good fish health status. The results show that there is high potential to use protein‐rich plant ingredients in diets for Atlantic cod.     

Effect of dietary zinc supplementation and phytase pre-treatment of soybean meal or corn gluten meal on growth, zinc status and zinc-related metabolism in rainbow trout, Oncorhynchus mykiss

Rainbow trout, Oncorhynchus mykiss, were fed diets containing untreated or phytase-treated soybean meal and corn gluten meal with or without 50 mg supplemental zinc kg–1 to determine if dietary phytate caused a zinc (Zn) deficiency. Fish fed diets containing untreated soybean meal and corn gluten meal without supplemental Zn (basal diet) showed no signs of a Zn deficiency after 170 d of weight gain. Weight gain, carcass protein content, total bone Zn, and alkaline phosphatase and carboxypeptidase B activities were not significantly altered in fish fed the basal diet. Dietary phytate removal and supplemental dietary Zn were not required to prevent Zn deficiency in rainbow trout fed a plant-based diet. Although bone Zn concentrations were reduced in fish fed the basal diet, total bone Zn increased in all fish regardless of dietary treatment. Future assessments of Zn status of fish should be based on changes in Zn-dependent metabolism or total bone Zn rather than on bone Zn concentration.     

Growth, feed efficiency, digestibility and nutrient distribution in Atlantic cod (Gadus morhua) fed two different fish meal qualities at three dietary levels of vegetable protein sources

Atlantic cod were fed six diets where the ratio of protein from fish meal to vegetable protein were varied from 91%, 67% to 46%, respectively. The experimental groups were performed in triplicate in a 20 week growth trial, increasing fish weight from about 167 g to 690 g. The vegetable protein sources constituted full-fat soybean meal and corn gluten meal at a fixed ratio of 1:2, and replaced either a high quality fish meal (DC_Mink 92.3%) or a lower quality fish meal (DC_Mink 85.6%) in the diet. All diets were extruded and balanced to be equal in gross energy, crude protein, lipid, carbohydrate, lysine and phosphorus. No difference in growth (SGR 1%) was observed comparing the two fish meal qualities. However, feed intake was significantly higher (9%) and feed efficiency lower (10%) for lower quality fish meal compared to high quality fish meal. Protein and amino acid digestibility was significantly reduced in the lower quality fish meal, while unaffected by vegetable protein inclusion for both fish meal qualities. Protein utilization as measured by protein efficiency ratio and net protein value was not affected by fish meal inclusion, except in the diet using lower quality fish meal and high vegetable protein inclusion. Lipid and energy digestibility was significantly reduced by vegetable protein inclusion for both fish meals. The lower fish meal quality increased lipid deposition in the liver and affected slaughter quality of cod by increasing HSI and dressing out percentage at low and intermediate substitution levels. Muscle composition showed small dietary changes except for arginine, while liver fatty acid composition clearly reflected fatty acid profile of full-fat soya in the diets. Corn gluten meal and full-fat soybean meal (2:1) can replace approximately 50% of dietary protein without affecting feed intake, growth, protein digestibility or slaughter quality of cod when exchanging high quality fish meal. For the lower quality fish meal diets some lower inclusion of vegetable protein sources seem to be acceptable.     

Preliminary evaluation of pea seed meal in diets for gilthead sea bream (Sparus aurata) juveniles

Juvenile gilthead sea bream with a mean initial body weight of 5 g were fed for 12 weeks with experimental diets containing 10% and 20% fishmeal protein (sole protein source in the control diet) replaced by processed pea seed meals. The processed pea seed meals were dehulled, defibred, extruded and microground pea seed meal (PSM1) or whole pea treated by infrared radiation and ground (PSM2). Apparent digestibility coefficients of the experimental diets were determined in a separate trial. At the end of the growth trial there were no significant differences in growth performance, feed utilization or whole-body composition among experimental groups. There were no differences in apparent protein digestibility among experimental groups (except for fish fed PSM1 at the lowest inclusion level). Both dry matter and energy digestibility of the diets, including PSM2 and with the highest inclusion level of PSM1, were significantly lower than those of the control diet. The results of this study suggest that pea seed meal may replace up to 20% fishmeal protein in diets for gilthead sea bream juveniles without affecting fish performance. Further studies should focus on technological treatments to increase utilization of pea seed meal carbohydrate, as both apparent dry matter and energy digestibility were affected by dietary inclusion level and by pea seed meal processing method.     

Enhancing the growth of Nile tilapia larvae/juveniles by replacing plant (gluten) protein with algae protein

Diets incorporating different levels of corn gluten meal replacement using biofuel algae or Spirulina protein at 0%, 25%, 50%, 75% and 100% were evaluated for larval/juvenile stage of Nile tilapia (Oreochromis niloticus). Fish averaging 0.02 g were divided into groups of 50. There were three replicates per every dietary treatment that were fed one of six diets for 11 weeks. Corn gluten protein was replaced with algae on the protein basis. All diets were supplemented with 1.5% lysine and 0.5% methionine. The experimental diets were formulated to contain 37 ± 2.8% protein and 14 ± 4.3% lipid in the form of fish oil and soybean lecithin (phospholipids source). The results indicated that algae positively affected feed consumption and fish growth up to the 50% replacement and then performance was depressed. Significant differences in concentration of individual minerals (Al, Fe, Zn and Cu) in the whole fish body were found. Mineral composition of algae might have affected growth when diets which contained more than 75% of plant protein were replaced with microalgae. These findings suggest that up to 50% of dietary corn gluten meal protein can be replaced with microalgae which significantly enhance fish growth.     

豆粕替代鱼粉对牛蛙生长、体组成、消化酶活力及肝脏生化指标的影响

为减少牛蛙饲料鱼粉使用量以降低养殖成本,研究了豆粕替代饲料中不同比例的鱼粉对牛蛙的生长性能、体组成、肠道消化酶活力和肝脏生化指标的影响。用豆粕分别替代0%、20%、40%、60%、80%和100%的鱼粉配制出6种等氮等能的实验饲料,每组饲料设3重复,养殖牛蛙60 d。结果显示,豆粕替代鱼粉对牛蛙摄食率、成活率、肝体指数、脏体指数、蛙体水分和灰分含量、蛙腿肌肉组成以及肝脏丙二醛含量的影响不显著;豆粕100%替代鱼粉显著降低牛蛙增重率、特定生长率、饲料系数、蛋白质效率、蛋白质累积率;随豆粕替代鱼粉比例的提高,牛蛙的肥满度和后腿指数呈下降趋势,替代100%鱼粉显著降低牛蛙肥满度,替代60%鱼粉显著降低牛蛙后腿指数;替代80%鱼粉显著降低牛蛙全体粗蛋白的含量;牛蛙全体粗脂肪含量随替代鱼粉比例的提高呈上升的趋势,替代100%鱼粉组粗脂肪含量最高;随着替代比例的提高,牛蛙肠道蛋白酶的活力显著降低,而肠道淀粉酶和脂肪酶活力显著提高。豆粕替代鱼粉显著影响肝脏超氧化物歧化酶和过氧化氢酶活力,其中超氧化物歧化酶活力最低值出现在替代80%鱼粉组,过氧化氢酶活力最低值出现在替代100%鱼粉组。基于以上实验结果,建议牛蛙饲料中豆粕可替代鱼粉的比例为60%~80%。     

Soybean meal and wheat flour,proper dietary protein sources for optimal growth of snail (<Emphasis Type="Italic">Semisulcospira coreana</Emphasis>)

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.