不同饵料投喂模式对中华绒螯蟹幼蟹生长和生理生化的影响

为研究池塘养殖过程中不同饵料投喂模式对中华绒螯蟹(Eriocheir sinensis)幼蟹生长和生理生化的影响, 实验以中华绒螯蟹幼蟹为研究对象, 比较了喜旱莲子草(Alternanthera philoxeroides)组(Diet1 组)、配合饲料组(Diet2 组)以及两者 1 1 ∶ 混合组(Diet3 组) 3 种饵料投喂模式下幼蟹生长、消化酶、抗氧化酶及免疫酶活性的变化。每个处理组设置 3 个重复, 实验周期为 120 d。结果表明: (1)养殖结束时, Diet2 组幼蟹的终末体重、增重率、特定生长率和肝胰腺指数均显著高于 Diet1 和 Diet3 组; (2) Diet2 和 Diet3 组幼蟹肝胰腺和躯体的粗脂肪含量显著高于 Diet1 组, 而灰分含量呈相反趋势; (3)幼蟹肝胰腺 α-淀粉酶活性在 Diet3 组最高(P<0.05), 而脂肪酶活性在 Diet2 组最高 (P<0.05); (4) Diet1 组幼蟹血清过氧化氢酶活性最高, 而 Diet2 组和 Diet3 组总抗氧化能力和丙二醛含量均显著高于 Diet1 组; (5) Diet1 组幼蟹肝胰腺过氧化氢酶酶活性最高, Diet2 组雌蟹超氧化歧化酶活性和总抗氧化能力活性最高 (P<0.05), Diet3 组雄蟹总抗氧化能力活性最高(P<0.05); (6) Diet2 组和 Diet3 组幼蟹血清中酸性磷酸酶和碱性磷酸酶活性均显著高于 Diet1 组, 而在雌雄蟹肝胰腺中, 三组间酸性磷酸酶和碱性磷酸酶活力不存在显著差异(P>0.05)。 因此, 在中华绒螯蟹池塘养殖模式下, 在合理的种植水花生的基础上投喂配合饲料有利于幼蟹生长、消化和脂肪积累, 以及增强幼蟹抗氧化和免疫能力。本研究可为配合饲料投喂模式的推广以及将水花生作为植食性饵料添加到中华绒螯蟹幼蟹配合饲料中的开发提供科学参考与理论基础。     

脊尾白虾与梭子蟹、贝类混养技术

脊尾白虾是我国特有的一种重要经济虾类。近年来，为提高海水池塘养殖的经济效益，我们开展了养殖新模式的探索，利用1．3hm^2（20亩）海水池塘进行了脊尾白虾与梭子蟹、贝类混养生产试验，获得成功。现将养殖生产的主要技术及基本情况报告如下：     

不同投喂频率对脊尾白虾生物钟基因表达、生长及肌肉成分组成的影响

为探究不同投喂频率对脊尾白虾(Exopalaemon carinicauda)生长的影响, 确定脊尾白虾养殖适宜投喂频率, 本研究分析了在不同投喂频率下脊尾白虾眼柄和肝脏中的生物钟基因表达节律变化, 评估了不同投喂频率对脊尾白虾生物钟系统同步性的影响, 并开展了生长及肌肉组成的同步养殖验证。结果表明: 在投喂频率为＜3 次/d 时, 生物钟基因的表达节律并没有随着投喂频率的改变而发生变化, 无论在眼柄或肝脏中均表现出相似的表达周期及表达顶相, 且各自的表达量间也无显著性差异变化。然而, 当投喂频率增加到 4 次/d 时, 肝脏中部分生物钟基因的表达节律发生了显著变化, 表现为表达周期改变、相位明显偏移及表达量变化。其中, 投喂频率为 3 次/d 时, 脊尾白虾眼柄与肝脏中生物钟基因表达节律的同步性最高。生长结果也显示, 脊尾白虾的生长性能随投喂频率升高(从 1 次/d 至 3 次/d 时)而升高, 3 次/d 时达到最高, 其特定生长率及增重率分别为(6.65±0.98)%/d 和(199.46±5.42)%。同时, 随着投喂频率升高, 脊尾白虾肌肉组织中的粗蛋白及粗脂肪含量也呈现上升趋势, 在 3 次/d 时达到最高, 分别为(19.98±0.04)%和(1.88±0.23)%。投喂频率对脊尾白虾肝脏中生物钟基因的表达节律有重要影响, 表明该因素对重置或调控脊尾白虾外周生物钟系统有一定的牵引作用。     

浙江省池塘养殖大口黑鲈和乌鳢的生长性能和养殖环境分析

2015年7-10月对浙江省杭州市6口养殖生产池塘内大口黑鲈和乌鳢的生长性能、池塘水质和底质状况进行了分析比较。所研究的池塘中,3口(B1、B2和B3)投喂配合饲料养殖大口黑鲈,2口(S1和S2)投喂配合饲料养殖乌鳢,1口(S3)投喂冰鲜鱼养殖乌鳢。试验结果:8月11日—9月4日,池塘B1内大口黑鲈体质量增加62 g/尾,池塘S1内乌鳢体质量增加113 g/尾,池塘S3内乌鳢体质量增加31 g/尾。研究期间,池塘S1和S2水中氨氮(TAN)、亚硝酸盐氮(NO_2~--N)、硝酸盐氮(NO_3~--N)、总氮(TN)、总有机碳(TOC)和底泥总磷(TP)均高于池塘B1、B2、B3;池塘S3水中TAN、活性磷酸盐(PO_4~(3-)-P)、TN、TP和底泥TN、TP、POC高于池塘S1和S2,但水中NO_2~--N、NO_3~--N、COD_(Mn)和TOC均低于池塘S1和S2。结果表明,采用配合饲料饲喂大口黑鲈和乌鳢可正常生长;投喂配合饲料时,乌鳢池塘水中TN和TOC的积累程度高于大口黑鲈池塘,表明乌鳢养殖池塘中有机质的积累程度高于大口黑鲈池塘。     

技术交流

<正>虎龙杂交斑健康养殖技术1.池塘养殖模式池塘条件:养殖池塘面积以2亩~3亩适宜,水深1.5米~2米。高位池养殖效果更佳。放养前彻底清塘、进口后水体彻底消毒、然后施肥培水。放养密度:每亩放养1500尾~2000尾。饲料投喂:饲料选用石斑鱼专用配合饲料,不同养殖阶段饲料规格作相应调整。日投喂量为鱼体重的1%~2%,每天投喂     

配合饲料在拟穴青蟹-脊尾白虾混养模式中的应用效果初探

为研究配合饲料在拟穴青蟹(Scylla paramamosain)-脊尾白虾(Exopalaemon carinicauda)混养模式中的应用效果,选取面积为5亩(15亩=1 hm2,下同)的青蟹-脊尾白虾混养池塘2口,分别投喂配合饲料+鲜杂饵料(试验塘)和鲜杂饵料(对照塘),开展为期70 d的养殖对比试验。结果显示:试验塘青蟹产量较对照塘增加33.5%,亩均效益提升28.3%,经济效益明显提高。试验塘青蟹的肌肉水分显著低于对照塘(P0.05),粗蛋白含量显著高于对照塘(P0.05);试验塘青蟹胃蛋白酶的活性相比于对照塘也有显著提升(P0.05)。试验表明,配合饲料在青蟹养殖实践中的应用具有可行性。     

配合饲料和冰鲜饵料对拟穴青蟹养殖的影响

本试验评估了投喂配合饲料和冰鲜饵料对拟穴青蟹(Scylla paramamosain)池塘混养模式的影响。经过5个月的养殖试验,结果显示:配合饲料组与冰鲜饵料组抽样青蟹的平均规格、形体学指标、肝胰腺指数和性腺指数均无显著差异(P0.05)。配合饲料组的青蟹肌肉中粗蛋白含量显著高于冰鲜饵料组(P0.05)。配合饲料组青蟹胃蛋白酶、肠蛋白酶的活性显著高于冰鲜饵料组(P0.05),胃淀粉酶活性显著低于冰鲜饵料组(P0.05)。冰鲜饵料组池塘水体的氨氮、亚硝酸盐氮、硝酸盐氮、磷酸盐和总有机碳指标均高于配合饲料组(P0.05)。在属水平上,冰鲜饵料组水样中的海命菌属等7种微生物菌的平均相对丰度显著高于配合饲料组(P0.05);冰鲜饵料组底泥中的地杆菌属等8种微生物菌的平均相对丰度显著高于配合饲料组(P0.05)。配合饲料组每667 m~2总产量(蟹+虾+贝)和利润分别为374 kg和6 210元,比冰鲜饵料组分别增加5.9%和42.6%。投喂配合饲料可以提高拟穴青蟹围塘养殖效益,具有推广可行性。     

浙南海水网箱主养鱼类配合饲料试验和推广探讨

为了在浙南海水网箱养殖中推广配合饲料,选择浙南海水网箱主养鱼类品种鲈鱼、大黄鱼、美国红鱼、黄姑鱼等进行配合饲料、冰鲜小杂鱼投喂养殖对比试验。试验结果:投喂冰鲜小杂鱼的饲料系数为8.22~10.21,投喂配合饲料的饲料系数为1.28~2.64;投喂配合饲料养成每千克鱼的平均饲料成本为18.63元,养成每千克鱼的总成本为25.64元;当小杂鱼的价格为每千克2.08元时,投喂小杂鱼和投喂配合饲料养殖每千克鱼的饲料成本相同,均为18.64元。试验结果表明,投喂配合饲料同样能养好海水鱼,冰鲜小杂鱼的价格是配合饲料推广的关键因素。     

不同饲料对军曹鱼组织消化酶活力的影响

比较研究了投喂冰鲜鱼和人工配合饲料的军曹鱼胃、前肠以及肝脏消化酶(蛋白酶、胰蛋白酶、淀粉酶和脂肪酶)活力.试验结果表明,(1)蛋白酶活力:前肠与肝脏的蛋白酶比活力,投喂配合饲料组显著高于冰鲜鱼组(P<0.05),而胃中的蛋白酶比活力以冰鲜鱼组显著高于配合饲料组(P<0.05);(2)胰蛋白酶活力:胃中胰蛋白酶比活力,冰鲜鱼组显著高于配合饲料组(P<0.05),前肠与肝脏的胰蛋白酶比活力配合饲料显著高于冰鲜鱼组(P<0.05);(3)淀粉酶活力:胃中的淀粉酶比活力,冰鲜鱼组显著高于配合饲料组(P <0.05),前肠的淀粉酶比活力则是配合饲料组显著高于冰鲜鱼组(P<0.05),两种饲料对军曹鱼肝脏淀粉酶比活力影响不显著(P>0.05);(4)脂肪酶活力:胃及前肠的脂肪酶比活力两种饲料间差异不显著(P>0.05),但肝脏的脂肪酶比活力则以配合饲料组显著高于冰鲜鱼组(P<0.05).     

大黄鱼专题系列讲座 大黄鱼精准投喂策略

<正>目前，大黄鱼养殖过程中主要投喂冰鲜杂鱼和人工配合饲料，且以冰鲜杂鱼为主。然而，大多数冰鲜杂鱼存在质量低下、携带病原菌、饵料系数高、投喂成本高、易造成养殖水体水质恶化和引发病害等问题。此外，低质量的冰鲜杂鱼还会引起大黄鱼肝脏脂代谢紊乱，降低抗病力，危害鱼体健康。因此，使用人工配合饲料全面替代冰鲜杂鱼势在必行。     

Effect of dietary Yucca schidigera extract on growth,total ammonia–nitrogen excretion and haematological parameters of juvenile striped catfish Pangasianodon hypophthalmus

A feeding trial with striped catfish, Pangasianodon hypophthalmus was performed to determine the effect of Yucca schidigera in practical diet on the growth, feed utilization, body composition, total ammonia–nitrogen (TAN) excretion and haematological parameters. A diet with fish meal as the main protein source without yucca extract was used as the control diet (Diet 1). Four diets were formulated with 0.075 (Diet 2), 0.1 (Diet 3) and 0.15 (Diet 4)% of yucca extract respectively. Fifteen fish per tank (initial mean weight 1.78 ± 0.05 g) were randomly allocated to 15 fibreglass tanks (80‐L) connected to a freshwater closed recirculation system (temperature 29.7 ± 1.0°C). The experimental diets were tested in triplicates for 12 weeks. The specific growth rate of fish fed Diet 4 was significantly higher when compared with fish fed Diet 1. The growth of fish fed diets Diet 2 and Diet 3 were not significantly different compared with fish fed the Diet 1. Striped catfish fed Diet 4 had significantly lower feed conversion ratio compared with fish fed Diet 1 and Diet 2 (P < 0.05).The incorporation of high level Yucca schidigera extract in the diets reduced TAN compared with Diet 1. Dietary inclusion of Yucca extract levels did not significantly affect the biometric parameters or whole body proximate composition of the striped catfish (P > 0.05). The PCV (%) in fish significantly increased with high levels of Yucca inclusion (Diet 4) compared with control diet. Fish fed Diet 4 showed significantly higher haemoglobin levels than Diet 1 (P < 0.05). The results indicate that dietary inclusion of Yucca schidigera extract is promising as a feed additive that could improve growth performance and some haematological parameters and the best Yucca schidigera level was 0.15%.     

Replacement of Fish Meal with Soybean Meal,Alone or in Combination with Distiller's Dried Grains with Solubles in Practical Diets for Pacific White Shrimp,Litopenaeus vannamei,Grown in a Clear‐Water Culture System

The objective of this study was to evaluate inclusion of distiller's dried grains with solubles (DDGS) as partial replacement of commercial, solvent‐extracted soybean meal (SBM) in fish meal‐free diets for Pacific white shrimp, Litopenaeus vannamei. Aquaria connected to a recirculating biofiltration system were utilized to evaluate growth, survival, and feed conversion of shrimp during the 8‐wk feeding trial. Each 110‐L aquarium was stocked with 15 shrimp (mean individual weight 0.99 g) and fed one of five diets: a diet containing 20% fish meal (FM), which served as the control (Diet 1); a diet containing 0% FM and 52.5% SBM (Diet 2); and diets containing 0% FM and either 10, 20, or 30% DDGS as partial replacement of SBM (Diets 3, 4, and 5, respectively). Shrimp were fed according to a pre‐determined feeding chart five times daily (0730, 1030, 1330, 1630, and 1930 h) and there were three replicates per dietary treatment. The results from the feeding trial demonstrated that final weight, weight gain (g), and percentage weight gain were significantly higher (P < 0.05) for shrimp fed Diet 1 (10.96 g, 10.01 g, and 1051%, respectively) compared to shrimp fed diets containing DDGS; however, shrimp fed diets containing DDGS had similar (P > 0.05) final weight, weight gain (g), and percentage weight gain as shrimp fed a diet containing 0% FM and 52.5% SBM (Diet 2). Feed conversion ratio (FCR) of shrimp fed Diet 1 (2.84) was significantly lower (P < 0.05) compared to shrimp fed any other diet. Survival (%) was not different (P > 0.05) among treatments and averaged 77.3% for the study. This study demonstrated that practical shrimp diets containing no FM had an adverse impact on growth performance of white shrimp when grown in a clear‐water system and that further research is needed to refine diet formulations when culturing shrimp in these systems when attempting to feed a diet without FM.     

Effect of biofloc technology on growth of speckled shrimp,Metapenaeus monoceros (Fabricus) in different feeding regimes

The effects of biofloc technology (BFT) were tested on growth performance, water quality, haemolymph parameters and hepatopancreas histology with and without BFT for the speckled shrimp. In this study, eight different experimental groups were formed (four BFT and four control groups) to measure the effects of different feeding rates on compensatory growth of speckled shrimp. BFT treatments were performed with zero water exchange and planned as BFT1: gradually feed decreasing group 4, 2 and 1% bw, BFT2: 4% bw, BFT3: 2‐days feed with 4% bw, 1‐day fasted, and BFT4: 1‐day feed with 4% bw, 1‐day fasted. In control treatment, the same trial groups were constituted for comparing with BFT at a 50% daily water exchange: C1 (gradually feed decreasing group: 4%, 2% and 1% bw), C2 (4% bw), C3 (2‐days feed with 4% bw, 1‐day fasted), C4 (1‐day feed with 4% bw, 1‐day fasted). There were significant differences between BFT and C groups in terms of some water quality (p < 0.05). In general, BFT had an effect on haemocyte profile. At the histological examination, there were no pathological findings in both BFT and control groups. The growth parameters of speckled shrimps in BFT groups, as well as the whole body crude protein ratios and crude ash contents, were higher than the control group (p < 0.05). The results confirmed that biofloc utilization increased with decreasing feeding.     

Effects of Dietary Lipids on Growth and Feed Utilization of Jade Perch,Scortum barcoo

To examine the effects of dietary lipids on the growth and feed utilization of jade perch juveniles, Scortum barcoo, diets containing 36.3% crude protein supplemented with increasing lipid levels (6, 9, 12, and 15% of the dry matter) were used to feed triplicate groups of 30 fish for 60 d. At the end of the experiment, more than 95% fish survived well from all diet groups (P > 0.05). Measurements on the weight gains and the daily specific growth rates indicated that fish fed with diets of 12 and 15% lipids exhibited higher growth rates (P < 0.05); evaluations for the feed conversion ratio and the protein efficiency ratio indicated that fish fed with 12 and 15% lipid diets used their feed and dietary proteins more efficiently (P < 0.05). The muscle lipid and dry matter contents increased dramatically in fish fed with higher dietary lipid levels (P < 0.05). The highest lipid contents were obtained from fish in the 15% lipid diet group and the highest amount of dry matters from the 12% lipid diet group. On the other hand, protein contents in fish muscles declined with increasing dietary lipid levels (P < 0.05), and the lowest values were shown in the 15% lipid diet group. Ash contents showed no significant differences from muscles of fish fed with four different diets (P > 0.05). Together, increasing lipid levels in fish diets was effective to improve fish growth, feed efficiency, and protein utilization.     

Effect of feeding frequency on growth,feed utilization,body composition and waste output of juvenile golden pompano (Trachinotus ovatus) reared in net pens

A 6‐week feeding trial was conducted to examine the effect of feeding frequency on growth, feed utilization efficiency, body composition and waste output of juvenile golden pompano Trachinotus ovatus reared in net pens. Fish (10.3 ± 0.5 g) were either fed a formulated diet containing 48.4% crude protein and 5.7% crude lipid at 0.5, 1, 2, 3 or 4 meals per day or fed a raw fish feed at two meals per day as a control. The weight gain (WG) increased with increasing feeding frequency from 0.5 to 3 meals per day (P < 0.05), but did not significantly change with the further increase in feeding frequency from 3 to 4 meals per day (P > 0.05). The feed intake (FI) was lower in fish fed at 0.5 or 1 meal per day than in fish fed at 2, 3 or 4 meals per day (P < 0.05). No significant differences were found in the feed conversion ratio (FCR), nitrogen retention efficiency (NRE), condition factor (CF), nitrogen waste output (NWO) and phosphorus waste output (PWO) between fish fed at 1, 2, 3 or 4 meals per day (P > 0.05), whereas no significant difference was found in the phosphorus retention efficiency (PRE) among the feeding treatments (P > 0.05). The body lipid content increased, whereas the contents of moisture and ash decreased, with the increase in feeding frequency (P < 0.05). At the same feeding frequency, fish fed the formulated diet exhibited lower FI, FCR, HSI, body moisture content, NWO and PWO, but higher NRE, PRE, body lipid content and body phosphorus content than those of fish fed the raw fish feed (P < 0.05). These results suggest that the formulated diet can satisfy nutrient requirements of juvenile golden pompano reared in net pens, and the suitable feeding frequency is 3 meals per day.     

Evaluation of Meat and Bone Meal as Replacement for Protein Concentrate in the Practical Diet for Sutchi Catfish,Pangasius hypophthalmus (Sauvage 1878), Reared under Pond Condition

An 80‐d feeding trial was conducted to evaluate meat and bone meal (MBM) as replacement of protein concentrate (PC) in practical diets for sutchi catfish, Pangasius hypophthalmus. Triplicate groups of juvenile sutchi catfish (initial weight 4.80 g) were stocked at the rate of 20,000 fish/ha in 12 earthen ponds (30 m² each). Four isocaloric diets (4.12 kcal/g) were formulated by replacing 0 (Diet 1, control), 33 (Diet 2), 67 (Diet 3), and 100% (Diet 4) PC protein with MBM. The growth parameters [final weight, % weight gain, and specific growth rate (SGR)] of fish fed Diets 1, 2, and 3 were not significantly different (P > 0.05) from each other but were significantly (P < 0.05) higher than those in Diet 4. The protein content in fish fed Diet 4 was significantly (P < 0.05) lower than the others. The total production of fish in different treatments ranged between 1917 and 2648 kg/ha/80 d. A simple economic analysis determined that the highest net profit (Tk. 52,965/ha) was obtained with Diet 2 and the lowest (Tk. 27,127/ha) with Diet 4 having 100% PC protein replacement. From the results of the study it is concluded that MBM can substitute up to 67% PC protein in catfish diet without hampering the growth and feed utilization.     

Effect of dietary willow herb,Epilobium hirsutum extract on growth performance,body composition,haematological parameters and Aeromonas hydrophila challenge on common carp,Cyprinus carpio

The present study was conducted to evaluate the use of Epilobium hirsutum extract in diet of common carp, Cyprinus carpio (20 ± 2 g). Different levels of plant extract (0%, 0.5%, 1, 3% and 3%+2‰ multivitamin (2 g of multivitamin per kg diet) were spread on commercial diet. The feed was offered by 8 weeks. Results showed that fish fed experimental diets had no significant difference (P>0.05) in specific growth rates, condition factor, feed conversion ratios and survival compared with control. There were no significant difference (P>0.05) in moisture, crude protein, crude lipid and ash content of common carp fed diets containing various levels of plant extract. The mortality of fish challenged by Aeromonas hydrophila have been recorded for 30 days after challenging, results showed that mortality decreased significantly (P<0.05) in fish fed diet containing plant extract compared with the control. The lowest mortality observed in group fed diet containing 3% plant extract. Haematological parameters showed that white blood cells had significantly (P<0.05) increased in infected and uninfected groups compared with the control. Red blood cells, haemoglobin and haematocrit had no significant change (P>0.05) in infected and uninfected groups compared with the control.     

Growth and economic analysis of freshwater prawn,Macrobrachium rosenbergii (de Man), produced with feeds substituting sunflower cake for fish meal,soya bean meal and mustard oil cake

A feeding trial with Macrobrachium rosenbergii was carried out to test the effectiveness of sunflower cake (SFC) as a replacement for conventional protein sources. Four isonitrogenous (~30% crude protein) and isocaloric (388–402 kcal) diets were formulated. Diet‐1 was a control made with conventional ingredients including fish meal, soya bean meal and mustard oil cake. Diet‐2, Diet‐3 and Diet‐4 were made with 30%, 40% and 50% SFC, respectively, replacing the usual protein sources used in Diet‐1. After 100 days, diets with SFC inclusion showed favourable growth and economic performance trends compared to control diet‐1, but without significant differences (p > .05). Better production (572.89 ± 62.99 kg/ha) was observed with Diet‐4 followed by Diet‐2, Diet‐3 and Diet‐1. Diet‐4 revealed the best feed conversion ratio (2.56 ± 0.24), specific growth rate (1.18 ± 0.05) and protein efficiency ratio (1.14 ± 0.10) among these diets. Whole carcass composition analysis revealed highest crude protein (18.19%) and lipid (4.43%) content in prawns fed Diet‐3 followed by Diet‐4. Highest total income, gross margin and benefit cost ratio (BCR) per hectare from prawns were US$5,759, US$2,623 and 1.84, respectively, found in Diet‐4. This study demonstrates that 30%–50% inclusion of SFC has favourable impacts on productivity and profitability compared with controls, with 50% SFC inclusion as the most cost‐effective diet for prawns without apparent compromise in growth, flesh quality or economics. The performances of the diets suggest that SFC may be a suitable substitute for fishmeal, soya bean meal and mustard oil cake in prawn feed. The effectiveness of higher SFC concentrations should also be investigated.     

饲料组成对银鲳幼鱼生长率及肌肉氨基酸、脂肪酸组成的影响

研究分析了饲料组成对银鲳(Pampus argenteus)幼鱼特定生长率(SGR)及肌肉氨基酸与脂肪酸组成的影响。实验共设4组不同的饲料组成,依次为饲料A(鱼肉糜)、饲料B(鱼肉糜+配合饲料)、饲料C(鱼肉糜+配合饲料+蛏子肉糜)和饲料D(鱼肉糜+配合饲料+蛏子肉糜+桡足类)。实验用银鲳幼鱼的平均体重为4.80±0.11 g,每组饲料设3重复,实验周期为9周。研究结果显示,不同饲料组成可显著影响银鲳的特定生长率,饲料A组的特定生长率最低,并显著低于其它各饲料组;饲料D组的特定生长率最高,且显著高于饲料B、C组的特定生长率(P<0.05);但饲料B、C组间银鲳特定生长率无显著性差异(P>0.05)。银鲳肌肉氨基酸与脂肪酸的分析结果显示,4组饲料组成对银鲳肌肉氨基酸的组成及含量并无显著性影响(P>0.05),但可显著影响肌肉脂肪酸的组成及含量(P<0.05)。饲料D组的多不饱和脂肪酸(PUFA)、高度不饱和脂肪酸(HUFA)及n-3HUFA含量均分别显著高于饲料A、B和C组(P<0.05),饲料B和C组的PUFA、HUFA及n-3HUFA均分别显著高于饲料A组(P<0.05),但饲料B、C组间并无显著性差异(P>0.05)。综合分析得出,丰富的饲料组成以及饲料中较高的HUFA含量均有利于银鲳幼鱼的生长。     

Alleviation effect of dietary cerium and its complex with chitosan oligosaccharide on cadmium accumulation in juvenile turbot,Scophthalmus maximus L., under cadmium stress

An 8 weeks feeding trial was conducted to investigate the effect of dietary cerium (Ce) and its complex with chitosan oligosaccharide (COS‐Ce) on growth performance and cadmium (Cd) accumulation of turbot, Scophthalmus maximus L. under Cd stress. The basal diet (Diet 0) was formulated without Cd and cerium as the control. Seven other experimental diets (Diets 1–7) were formulated with supplementation of 50 mg Cd²⁺/kg feed, 50 mg Cd²⁺/kg and 50 mg Ce³⁺/kg feed, 50 mg Cd²⁺/kg and 100 mg Ce³⁺/kg feed, 50 mg Cd²⁺/kg and 200 mg Ce³⁺/kg feed, 50 mg Cd²⁺/kg and 50 mg COS‐Ce/kg feed, 50 mg Cd²⁺/kg and 100 mg COS‐Ce/kg feed, and 50 mg Cd²⁺/kg +200 mg COS‐Ce/kg feed. Results of the present study showed that, compared with the control group, the condition factor in fish fed the diet with 50 mg Cd²⁺/kg feed (Diet 1) was significantly lower, whereas the Cd concentration in liver and kidney of fish fed the diet with 50 mg/kg Cd²⁺ (Diet 1) was significantly higher (P < 0.05). The high Cd accumulation of fish fed diets with sole 50 mg/kg Cd (Diet 1) could be significantly decreased by 51.72% after supplementation of 200 mg COS‐Ce/kg in the diet (Diet 7). These results suggested that elevated COS‐Ce could effectively protect against dietary Cd accumulation in turbot.