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.     

Effect of dietary replacement of fish meal by soybean protein concentrate on growth performance and phosphorus discharging of juvenile black sea bream,Acanthopagrus schlegelii

The 8‐week experiment was conducted to evaluate the effects of partial replacement of fish meal (FM) with soybean protein concentrate (SPC) on juvenile black sea bream, Acanthopagrus schlegelii (10.70 ± 0.04 g). Diets were formulated to replace FM protein by SPC at 0, 8, 16, 24, 32 or 40% (designated as T1, T2, T3, T4, T5 and T6, respectively). Diets except T1 were supplemented with phytase at 2000 phytase activity U kg^?1. The results showed that survival rate, growth performance and feed utilization were not significantly affected by increasing dietary SPC. Fish fed diet T3 had higher feed intake compared to those fed T1, T2 and T5 diets. Whole body compositions of black sea bream were significantly influenced by SPC replacing FM except for protein, ash and phosphorus content. Condition factor of fish was significantly lower in T2 than that of fish in T3 group. Apparent digestibility coefficients (ADCs) of dry matter was higher in fish fed T6 diet than those of fish fed T1 and T2 diets, ADCs of phosphorus increased with dietary SPC level up to T3 and then decreased. The results obtained in this study indicate that FM protein could be effectively replaced by SPC protein with phytase in diet of black sea bream.     

Tributyrin‐supplemented high‐soya bean meal diets of juvenile black sea bream,Acanthopagrus schlegelii: Study on growth performance and intestinal morphology and structure

An 8‐week growth trial was conducted to evaluate the effects of different levels of tributyrin supplementation in a high‐soya bean meal diet on juvenile black sea bream (11.30 ± 0.16 g). The positive control (PC) diet contained 45% fishmeal and 20% soya bean meal, while the negative control (NC) contained 12% fishmeal and 45% soya bean meal. Graded levels of tributyrin were added to the NC diet at 0.05% (TB 0.05), 0.1% (TB 0.1), 0.2% (TB 0.2), 0.4% (TB 0.4) and 0.8% (TB 0.8). Ultimately, the fish fed the PC diet had a higher weight gain and specific growth rate than the fish fed other diets. The fish fed the NC diet had the lowest growth, and TB 0.05–TB 0.2 diets increased growth performance while TB 0.4–TB 0.8 diets caused reduction in growth. Dietary tributyrin supplementation improved protease activity and enhanced antioxidant capacity. Compared with the fish fed the NC diet, the fish fed the tributyrin‐supplemented diets had improved gut morphology and structure, and the results were similar to those of the fish fed the PC diet. Furthermore, the analysis of the dose response with second‐order polynomial regression indicated that the optimum tributyrin supplementation for juvenile black sea bream is 2.24 g/kg in the 45% soya bean meal diet.     

Partial replacement of fishmeal with Clostridium autoethanogenum single‐cell protein in the diet for juvenile black sea bream (Acanthopagrus schlegelii)

Clostridium autoethanogenum protein (CAP) is a single‐cell protein derived from ethanol production and may have potential to become a substitute for fishmeal in aquafeeds. A 70‐day feeding trial was conducted with black sea bream (Acanthopagrus schlegelii) (mean initial weight 6.03 ± 0.09 g) to evaluate partial replacement of fishmeal with CAP in diets. Seven isonitrogenous and isoenergetic diets were formulated with graded levels of CAP (0, 4.85, 9.70, 14.55, 19.40, 38.80 and 58.20%) to replace fishmeal. The inclusion of CAP at all dietary levels tested did not significantly affect the growth performance (p > .05). Fish fed the CAP58.20% diet showed a significantly lower feeding rate, with significantly higher protein efficiency ratio and feed efficiency ratio compared with fish fed the other diets (p < .05). No statistical differences were found in dorsal muscle and whole‐body compositions. Total superoxide dismutase in serum of fish fed CAP58.20% diet was significantly lower compared with that of the control. Malondialdehyde, catalase, total antioxidant capacity and digestive enzyme activities revealed no significant differences among dietary treatments. Phosphorus retention efficiency significantly increased, and phosphorus discharge showed a downward trend with increasing CAP inclusion levels. In conclusion, the results indicated that CAP is a safe and effective alternative protein source, which can replace fishmeal in the diet of black sea bream up to 58.20%, without adverse effects on growth performance, antioxidation and digestive enzyme activity. This study has shown the potential of converting industrial waste into a high protein feed ingredient for aquafeeds.     

Partial replacement of fishmeal with corn gluten meal,pea protein isolate and their mixture in diet of black sea bream (Acanthopagrus schlegelii) juveniles: Effects on growth performance,feed utilization and haematological parameters

Corn gluten meal (CGM), pea protein isolate (PPI) and their mixture (CPP, 1:1 ratio) were evaluated as fishmeal (FM) alternatives in black sea bream (Acanthopagrus schlegelii) juveniles (9.02 ± 0.12 g). A FM diet was designed as control, and other six diets had 20% and 40% FM protein replaced by CGM, PPI and CPP, respectively, with the supplementation of crystalline methionine, arginine and lysine. After the 8‐week feeding trial, significantly lower weight gain was found in fish fed the 40% CGM diet (p < .05), whereas other treatments had no statistical difference (p > .05). The values of feed efficiency ratio and feed intake, as well as proximate compositions of muscle and whole body, were not significantly influenced in all treatments. Apparent digestibility coefficients (ADCs) of dry matter, crude protein, threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine were significantly influenced by protein source. Fish fed the 40% CGM diet had significantly higher content of essential amino acid in muscle than that of the 20% PPI diet. Fish fed the 40% CGM diet had significantly lower content of serum cholesterol than other treatments (p < .05). Elevated serum superoxide dismutase activity was found in fish fed the 40% plant protein diets. In conclusion, between 20% and 40% FM protein could be replaced by CGM, while about 40% FM protein derived from PPI and CPP could be applied in black sea bream.     

Influence of dietary levels of soybean meal on the performance and gut histology of gilthead sea bream (Sparus aurata L.) and European sea bass (Dicentrarchus labrax L.)

The present study was performed to determine the effect of soybean meal (SBM) on the performance and gut histology of gilthead sea bream and European sea bass. Three isonitrogenous and isolipidic extruded diets (crude protein, 470 g kg⁻¹ diet; crude fat, 200 g kg⁻¹ diet) were formulated containing 0 (0 SBM), 180 (180 SBM) and 300 (300 SBM) g kg⁻¹ diet SBM and tested on both species in two separate experiments. Fish at an initial average weight of around 18 g were randomly allocated to 800 L square tanks connected to a closed recirculating system. The trials lasted 80 days for sea bream and 89 days for sea bass. Fish were hand-fed to apparent satiation. Increasing the level of SBM had no significant effects on the specific growth rate, feed intake and feed conversion rate in both the species. In the sea bream distal intestine, lamina propria was moderately and diffusely expanded in some fish due to an increase in cell infiltration represented by mononuclear cells, this finding being more frequent in animals fed diet 300 SBM. No other morphological alterations in intestinal folds, enterocytes or other inflammation signs were noticed in the sea bream distal intestine of any group. No histological differences were found in sea bass in any experimental group.     

Effect of dietary ascorbate fortification on lipolysis activity of juvenile black sea bream Acanthopagrus schlegeli

ABSTRACT:   Hatchery-reared black sea bream Acanthopagrus schlegeli juveniles averaging 0.05 g in body weight were fed either a control diet (commercial diet) or an experimental diet in which the commercial diet was fortified with 50 mg l -ascorbyl 2-monophosphate Mg (APM)/100 g diet for 50 days. Calcium ascorbate supplemented as a vitamin mixture in the control diet was completely destroyed during storage. Fortification with APM significantly increased the ascorbic acid levels in the muscle, liver, brain and eye. Although APM fortification did not influence growth, survival or fish body composition, adipocyte diameter in the intraperitoneal fat body (IPF) was significantly reduced. After the feeding experiment, the fish were kept for 39 days without feeding. Fortification with APM resulted in high survival, high muscle protein retention and low body weight loss. The results suggested the necessity of fortification with an adequate amount of ascorbate in the diet. While fatty acid compositions of the IPF, muscle and liver were not significantly influenced by APM fortification, characteristic changes in the fatty acid profile were found after starvation. Vitamin C and highly unsaturated fatty acids seemed crossly interactive in relation to lipolysis activity in black sea bream juveniles.     

Effect of dietary supplemental l‐carnitine on growth performance,body composition and antioxidant status in juvenile black sea bream,Sparus macrocephalus

Effects of dietary l ‐carnitine were studied in juvenile black sea bream (Sparus macrocephalus). The semipurified basal diet [crude protein 450 g kg^?1 dry matter (DM); crude lipid 126 g kg^?1 DM] was formulated to choose white fishmeal as the protein source and fish oil plus corn oil (1 : 1) as the lipid source. Six diets (control + diets 1–5) containing 0.1, 0.12, 0.16, 0.24, 0.39 and 1.1 g of l ‐carnitine kg^?1 diet were fed to triplicate groups of black sea bream (initial weight 13.10 ± 0.05 g) for 8 weeks. At the end of the feeding trial, growth performance, body composition and antioxidant status were determined. The results showed that relative growth rate (RGR) was significantly improved by the elevation of dietary l ‐carnitine level from 0.1 to 0.24 g kg^?1, but decreased with further increment (P < 0.05). Lipid content decreased significantly (P < 0.05) in the dorsal muscle whereas increased (P < 0.05) in the liver with the addition of dietary l ‐carnitine. Dietary l ‐carnitine supplements elevated enzymatic antioxidants (superoxide dismutase, SOD; catalase, CAT; glutathione‐S‐transferase, GST) activities (P < 0.05) yet decreased the content of non‐enzymatic factor, total sulphydryl groups (TSH) (P < 0.05). In summary, the optimum dietary l ‐carnitine level was 0.284 g kg^?1 diet by second‐polynomial regression analysis based on RGR (y = ?647.4x² +367.97x + 234.55; R² = 0.977, x = dietary l ‐carnitine levels, y = RGR), and dietary l ‐carnitine addition within the levels adopted in our study could depress lipid peroxidation in tissues of juvenile black sea bream.     

Stock enhancement programme for black sea bream, Acanthopagrus schlegelii (Bleeker), in Hiroshima Bay, Japan: a review

This paper reviews the stock enhancement programme for black sea bream ( Acanthopagrus schlegelii ) in Hiroshima Bay. This bay is one of the biggest production areas for black sea bream in Japan, accounting for about 10% of the total catch of the species in this country in 2004. After intensive fishing pressure caused a drastic decline in the catch of the species in this bay in the 1970s, a stock enhancement programme was conducted in its northern part since 1982 to restore the depleted population. The number of black sea bream juveniles released in 1996 surpassed 9 million, representing the third main species stocked in Japan. Almost 1.4 million of these juveniles were released into Hiroshima Bay. The fast acclimatization of hatchery-reared juveniles released into the bay may have contributed to the recovery of landings in the late 1980s and 1990s. However, this recovery was accompanied by a reduction in the market price of black sea bream. Further studies to assess the effectiveness of the stock enhancement programme as well as the carrying capacity of Hiroshima Bay to maintain the stock of black sea bream at a stable, healthy level are desirable. The necessity of evaluating the secondary effects derived from using a reduced number of breeders as well as finding new markets are suggested.     

Availability of black soldier fly meal as an alternative protein source to fish meal in red sea bream (Pagrus major,Temminck & Schlegel) fingerling diets

Black soldier fly meal (BM) is an outstanding candidate as a fish meal (FM) substitute because it contains relatively high protein and essential amino acids. In this study, we replaced FM in red sea bream diets (Pagrus major) with BM to investigate its effect on growth and feed utilization. Six isonitrogenous and isolipidic experimental diets were prepared by substituting 0%, 20%, 40%, 60%, 80% and 100% FM protein with BM (Control, BM20, BM40, BM60, BM80 and BM100, respectively). After the 8-week feeding trial, final body weight, weight gain, specific growth rate and feed efficiency decreased linearly with increasing dietary BM level (p < 0.05). Apparent digestibility of protein and fat and serum total cholesterol concentration decreased with increasing dietary BM levels (p < 0.05) Final body weight, WG, SGR and FE against dietary BM level had breaking points of 76.2%, 41.7%, 76.5% and 60.0%, respectively, in segmental regression analysis. In conclusion, the results suggest that BM can replace a maximum of 41.7% of FM in the diet of red sea bream without compromising growth performance or feed efficiency for 56 days.     

Effect of dietary fermented soybean meal on growth,intestinal morphology and microbiota in juvenile large yellow croaker,Larimichthys crocea

An 8‐week feeding trial was conducted to evaluate the effect of replacement of fish meal (FM) with fermented soybean meal (FSM) on growth performance, intestinal morphology and microbiota of juvenile large yellow croaker (Larimichthys crocea). Replacement ratio of FM with FSM were 0%, 15%, 30%, 45%, 60% and 75%, respectively (marked as FSM0, FSM15, FSM30, FSM45, FSM60 and FSM75). The results indicated that the survival ranged from 84.78% to 99.44%, and no significant differences were observed among all treatments (p > 0.05). Weight gain ratio (WGR) and specific growth rate (SGR) significantly decreased when the replacement level of FM protein exceeded 60%, and fish fed the FSM60 and FSM75 diets had lower WGR and SGR than those fed the other diets. Feed intake (FI) and feed conversion rate (FCR) significantly increased with replacement levels of FM increasing. Illumina high‐throughput sequence analyses showed that the alpha diversity did not differ among the diets of FSM0, FSM15 and FSM75. The whole community of tested samples was not modified by FSM, Firmicutes and Proteobacteria were the dominant flora in the intestines based on the phyla level. The dominant phyla in the water sample were Proteobacteria, Bacteroidetes. Fish fed the diet containing FSM75 significantly reduced the species abundance of Paenibacillus. There was a certain correlation between the intestine microbiota and SGR, antioxidant, and immune. Results indicated that up to 45% of FM can be replaced by FSM without negative effects on growth performance and intestinal integrity of juvenile large yellow croaker.     

Compensatory growth of juvenile black sea bream,Acanthopagrus schlegelii with cyclical feed deprivation and refeeding

An 8‐week feeding trial was conducted to evaluate compensatory growth of juvenile black sea bream, Acanthopagrus schlegelii (initial weight 9.56 ± 0.12 g) in fifteen 300 L indoors flow‐through circular fibreglass tanks. Feeding regimes was designed as follows: the control group (fed continuously), and S1, S2, S3 and S4 groups experienced 1, 2, 3 and 4 days of feed deprivation and then refeeding for the remaining days per week respectively. Changes in body weight, specific growth rate (SGR), feed intake (FI) and feed efficiency ratio (FER) were examined biweekly during the trial. At the end of the cyclical feeding periods, survival was not significantly affected by feeding strategy (P > 0.05). Final body weight of fish in S1 group was significantly higher than the control group (P < 0.05) after an 8 weeks trial, and fish in the S2 group reached the same body weight of the control fish (P > 0.05), however, the growth data in the S3 and S4 groups could not catch‐up with the control treatment (P < 0.05). In the first 4 weeks, SGR values of fish with feed deprivation more than 2 days per week were inferior to those of control group (P < 0.05); however, no significant differences of SGR were observed among the groups for the last 4 weeks (P > 0.05). FI increased significantly with the starvation days increasing during the whole feeding trial (P < 0.05). At the periods 2, 4 and 6 weeks, FER values increased significantly with increasing feed‐deprivation days up to S2 group and then levelled off (P < 0.05); however, FER in S2 group was only higher than that in S0 and S1, but no significant differences were found among the other treatments at the end of week 8. Significant differences were found in apparent digestibility coefficients (ADCs) of dry matter and crude protein among the treatments, while ADCs of crude lipid were unaffected. Protein and lipid contents in whole body and dorsal muscle showed declining tendency with increasing food deprivation days, while moisture contents tended to increase (P < 0.05). Serum parameters were markedly affected by feeding regimes except for total protein concentration and thyroxine level. The present results indicated that starvation for 1 and 2 days per week of juvenile black sea bream could achieve over‐compensation and complete compensation respectively. However, in case of longer term feed restriction regime, fish failed to obtain good growth performance.     

Effects of extrusion and inclusion level of soybean meal on diet digestibility, performance and nutrient utilization of gilthead sea bream (Sparus aurata)

The objective of this study was to evaluate the effects of soybean meal inclusion and treatment on the performance of two sizes of gilthead sea bream (small, 9 g and large 50 g mean initial weight). Seven diets were fed containing soybean meal, before (SBM) and after (SBMex) its extrusion, at increasing levels (0% as control and about 20, 30, and 40% for both soy forms used). For large fish effects on digestibility, as well as on trypsin activity levels and moisture at upper (UI), mid (MI) and lower (LI) intestine were also evaluated, following the growth trial. All experiments were conducted at 22 ± 2 °C. Specific growth rate and whole body composition were not affected by soy inclusion, however an adverse effect of inclusion level on feed conversion ratio and protein productive value was apparent for both soy products and fish sizes. Extrusion of soy affected differently large and small fish improving both protein productive value and feed conversion ratio of large fish, but only protein productive value of small fish. Plasma cholesterol decreased with inclusion level of both types of soy, the effect being significant only at the higher level. Liver lipid and glycogen deposition in large fish appeared to be mostly affected by digestible starch intake, increasing with increased intakes, the same being apparent for hepatosomatic index. Soy inclusion did not appear to have any effect on nutrient digestibilities. Trypsin activity (TA) was decreased from UI to LI for all diets and was significantly higher in C diet compared to all other diets at all segments. Extrusion of SBM increased significantly TA levels. Hydration of digesta in LI increased for low soy levels and decreased for high soy levels compared to the control diet.     

Effects of dietary vitamin E supplementation on growth performance, lipid peroxidation and tissue fatty acid composition of black sea bream (Acanthopagrus schlegeli) fed oxidized fish oil

A 9-week feeding experiment was conducted to evaluate the effects of dietary vitamin E supplementation on growth, lipid peroxidation and fatty acid composition of black sea bream fed oxidized oil. The FL and OL diets contained fresh fish oil and oxidized oil, respectively, without additional vitamin E supplementation. Another four α-tocopherol levels (150, 250, 450 and 800 mg kg⁻¹ diet) were used within the OL diet, giving a total of six experimental diets. Fish were hand-fed to apparent satiation twice daily. At end of the trial, the weight gain and survival rate of fish were significantly reduced by diets with oxidized oil, whereas hepatosomatic index was remarkably high in fish fed oxidized oil diet. However, vitamin E supplementation to diet significantly improved growth performance and increased vitamin E content in the liver. Although, liver thiobarbituric acid reactive substances and docosahexaenoic acid were significantly increased by dietary oxidized oil, their levels were reduced by dietary vitamin E supplementation. Our results indicate that the fish were performing the best at intermediate concentrations of α-tocopherol and a dose of >150 mg α-tocopherol kg⁻¹ diet could reduce lipid peroxidation and improve fish growth performance when oxidized oils exist in diet.     

Ontogeny of tolerance to and avoidance of ultraviolet radiation in red sea bream Pagrus major and black sea bream Acanthopagrus schlegeli

ABSTRACT:   Ontogenetic changes of tolerance to, and avoidance of, ultraviolet-B radiation (UV-B) were examined in red sea bream Pagrus major and black sea bream Acanthopagrus schlegeli . In the tolerance experiment, larvae and juveniles (age 13–46 days) were put in beakers, and were exposed to one of five different levels of UV-B radiation (1.8, 1.1, 0.2, 0.1, and 0 W/m²) for one hour. Their survival rates were calculated either 12 or 24 h later. In the avoidance experiment, fish (age 3–49 days) were put in a long experimental tank, half of which was covered with UV-blocking film and placed under two levels of UV-B radiation (1.1 and 0.2 W/m²), and their avoidance indices were calculated. Black sea bream had significantly better survival compared to red sea bream for most ages. Only black sea bream of ages 37 and 49 days showed significant avoidance of UV radiation under the higher level of UV-B, whereas both species did not show avoidance on any days at the lower level. The present results suggest that black sea bream are significantly better adapted to habitats with high UV-B radiation, than red sea bream, reflecting that back sea bream live in shallower waters through their early life stages.     

中性植酸酶替代磷酸二氢钙对黑鲷生长和磷利用的影响

以鱼粉、豆粕、菜粕等为蛋白原料设计配方, 磷酸二氢钙的添加量分别为1.5%、1.0%、0.5%和0(对应的饲料组为P1.5、PP1.0、PP0.5和PP0组), 其中PP1.0、PP0.5和PP0组中均添加200 mg/kg的中性植酸酶, 开展为期8周的黑鲷(Acanthopagrus schlegelii)养殖实验, 以探讨中性植酸酶替代磷酸二氢钙对黑鲷生长和磷利用的影响。结果显示, 黑鲷摄食实验饲料8周后, 各组间成活率无显著差异(P>0.05); 摄食饲料PP1.0、PP0.5和对照组(P1.5组)实验鱼的增重率无显著差异(P>0.05), 但均显著高于PP0处理组, 饲料系数则显著低于PP0处理组(P<0.05)。摄食不同饲料的黑鲷全鱼中蛋白质、脂肪、灰分及钙磷含量在不同组间均无显著差异(P>0.05)。添加植酸酶的各组鱼磷的表观消化率均显著高于对照组(P<0.05)。随着磷酸二氢钙添加量的降低, 黑鲷对干物质和蛋白质的表观消化率呈升高的趋势, 当饲料中磷酸二氢钙的添加量降到0时, 黑鲷对干物质和蛋白质的表观消化率显著高于对照组(P<0.05)。以上结果说明, 在本研究配方下, 黑鲷正常生长对饲料有效磷的需求量≥0.51%; 磷酸二氢钙可部分被植酸酶替代, 当黑鲷饲料中含有20%鱼粉、32%豆粕和12%菜粕, 且植酸酶添加量为200 mg/kg时, 与饲料中添加1%的磷酸二氢钙相当; 在不影响黑鲷生长的前提下, 植酸酶部分替代磷酸二氢钙不仅可降低无机磷的添加, 同时可提高饲料中磷的利用率, 降低磷排放。

     

Effects of the total fish meal replacement by soybean meal on growth parameters,serum biochemistry,and hepatic and intestinal histology of juvenile blunt snout bream (Megalobrama amblycephala)

ABSTRACT

Fish meal is the main protein source in fish diet, but due to its unsustainability, it has to be replaced with more sustainable protein sources, such as soybean meal (SBM), in fish feeds. As SBM often produces negative effects on fish growth and health, we conducted an eight-week trial of complete fish meal replacement with SBM in the diet of juvenile (48.2 ± 0.55 g) blunt snout bream (Megalobrama amblycephala), a herbivorous cyprinid fish native to the Yangtze basin (China). SBM-fed fish exhibited: a worsened growth performance; improved survival rate (P > 0.05); elevated serum triglycerides and total cholesterol but reduced low-density lipoprotein in plasma (P < 0.05); mild lipid droplet accumulation and swelling of the liver; elevated goblet cell counts and mild signs of enteritis in the intestines. With negligible effects on growth and mild effects on health, M. amblycephala appears to be comparatively tolerant of SBM, but total fish meal replacement is not recommended. Future studies should aim to identify the SBM tolerance threshold in long-term growth trials.     

大豆替代豆粕对中华绒螯蟹生长、消化酶活力和抗氧化能力的影响

为探讨中华绒螯蟹幼蟹的饲料大豆替代豆粕的适宜替代量,配制4种不同替代水平(0、40%、60%和80%)的等氮等能饲料,饲喂初重(5.34±0.19)g的中华绒螯蟹幼蟹5个月,测定其生长性能、消化酶活性和抗氧化能力。结果显示,各组蟹的增重率、饲料系数和存活率差异不具统计学意义(P>0.05);随着大豆替代豆粕的比例上升,蟹肝胰腺胰蛋白酶、脂肪酶和淀粉酶水平呈显著下降趋势(P<0.05);各组蟹肝胰腺超氧化物歧化酶、过氧化氢酶及总抗氧化活力的水平差异均不具统计学意义(P>0.05)。综上所述,饲料中用大豆替代40%~80%的豆粕不会显著影响中华绒螯蟹的生长性能和抗氧化能力,但是对机体的消化酶有一定的负面影响。     

Effects of replacing fish meal with soybean meal,with or without dietary arginine,on growth performance,immune indices and intestinal morphology of grouper,Epinephelus malabaricus

A 10‐week feeding experiment was conducted to evaluate the effects of replacing fish meal with soybean meal (SBM), with or without dietary arginine (Arg), on growth performance, immune indices and intestinal morphology of grouper, Epinephelus malabaricus. Nine experimental diets were formulated to contain 20%, 30% and 40% fish meal protein (FMP) replaced using SBM and 0, 0.5% and 1% dietary Arg supplementation. The results showed that weight gain (WG) of fish was significantly affected by the interaction of substitution level and Arg supplemental level. The maximum WG occurred at the 30% FMP substitution level and the 0.5% Arg supplemental level. The immune assay showed that the interaction between the two levels significantly influenced the production of serum nitric oxide but did not affect serum IgG concentration and alkaline phosphatase activity or the liver IGF‐1 gene expression. Significant interaction effects between the two levels were observed in muscle layer thickness (tML) and fold height (hF) in the proximal and mid‐intestine. High SBM level in diets reduced the tML and hF in the entire intestine. The results suggested that the interaction of 30% FMP substitution level and Arg supplemental level of 0.5% most benefitted growth performance, immune indices and intestinal structure of grouper.