Effect of Fouling in Daya Bay Scallop chlamys nobilis (reeve) Cultivation:Food Competition and Nutrient Release

Biofouling is an important factor that affects bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitors for food resource with the cultured species. The present study was conducted to measure the impact of fouling on food uptake and nutrient release in April, 2006 in Daya Bay near Guangzhou, China. Results showed that fouling organisms had significant effect on food uptake and nutrient release. The chlorophyll a uptake rate of fouled scallops was 7.53 / Lh ±1.416 / Lh in April, significantly higher than those of cleaned scallops, Le., 4.23 / Lh±2.744 / Lh. The consumption of total particulate matter by fouled scallops in April was 5.52 / Lh± 0.818 / Lh; the corresponding results for cleaned scallops are 2.49 / Lh ±0.614 / Lh Fouling increased ammonia release significantly. The ammonia release rate of fouled scallops was 33.81/Lh ±7.699 / Lh in April, while cleaned scallops released 2.46 / Lh ±0.511 / Lh ammonia. Phosphate uptake of fouled scallops was 2.01± 0.699 / Lh and cleaned scallops released phosphate 6.01 / Lh ＋ 0.876 / Lh in April. There was not significant difference in nitrate consumption between fouled and cleaned scallops. According to the phytoplankton classification of input and output water samples, fouled scallops filtered more phytoplankton species than cleaned scallops. Therefore, this study showed that fouling contributed much to phytoplankton depletion and concentration increase of ammonia in water.

Correlation and path coefficient analysis for phenotypic traits of noble scallop Chlamys nobilis

In April of 2006, a base population of the noble scallop Chlamys nobilis was established by collecting parental breeders from the stocks in Wushi, Zhanjiang. In December of 2006, 200 individuals were randomly sampled from the base population and subjected for correlation and path coefficient analysis. It was found that there were statistically significant phenotypic correlations among the traits （P 〈 0.01）. Total weight was significantly and positively correlated with the shell length （r = 0.934 3）, shell height （r = 0.895 9）, shell width （r = 0.899 1 ）, muscle weight （r = 0.882 0） and shell weight （r = 0.937 9）, respectively. Shell length, shell width, muscle weight, shell height and shell weight had positive and direct effects on the total weight, with values of 0.397 1, 0.321 9, 0.172 1, 0.089 6 and 0.066 9, respectively. Shell length, shell width and muscle weight had higher direct effects on the total weight than shell height and shell weight. A combined evaluation of correlation, direct effects and indirect effects showed that direct selection for shell length, shell width, muscle weight, shell height and shell weight would be effective to improving the total weight. It was concluded that these traits could be regarded as the selection criteria in breeding programs of the species.

Effect of Fouling Organisms on Food Uptake and Nutrient Release of Scallop (Chlamys nobilis, Reeve) Cultured in Daya Bay

Biofouling is an important factor that affects the bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitors for food resource with the cul- tured species. The present study was conducted to measure the impact of fouling on food uptake and nutrient release in April and June, 2006 in Daya Bay near Guangzhou, China. Results showed that fouling organisms had significant effect on food uptake and nutrient release. The chlorophyll a uptake rate of fouled scallops was 7.53 Lh-1 ± 1.416 Lh-1 and 11.94 Lh-1± 2.497 Lh-1 in April and June, respectively, significantly higher than those of cleaned scallops, i.e., 4.23 Lh-1 ± 2.744 Lh-1 and 2.57 Lh-1 ± 1.832 Lh-1 respectively. The consumption of total particulate matter by fouled scallops in April and June was 5.52 Lh-1 ± 0.818 Lh-1 and 3.07 Lh-1 ± 0.971 Lh-1, respectively; the corresponding results for cleaned scallops are 2.49 Lh-1 ± 0.614 Lh-1 and 2.37 ± 1.214 Lh-1, respectively. Fouling in- creased ammonia release significantly. The ammonia release rate of fouled scallops was 33.81 Lh-1±7.699 Lh-1 and 76.39 Lh-1 ± 9.251 Lh-1 in April and June, while cleaned scallops released 2.46 Lh-1 ± 0.511 Lh-1 and 7.23 Lh-1 ± 1.026 Lh-1 ammonia, respectively. Phos- phate release of fouled scallops was 22.72 Lh-1 ± 9.978 Lh-1 in June and cleaned scallops released phosphate 6.01 Lh-1 ± 0.876 Lh-1 in April. Therefore, fouling contributed much to food reduction and concentration increase of ammonia and phosphate in water.

Effect of enzymatic fish frame protein hydrolysate on freeze-induced denaturation of myofibrillar protein from bighead carp fish （Aristichthys nobilis ） during frozen storage

Three kinds offish frame protein hydrolysates （PPH, APH and FPH） were prepared from fish frame of red drum （ Sciaenops ocellatus ） by papain, alkaline proteinase and flavorzyme treatment. The hydrolysates were mainly composed of peptide （83.5 % -84.6% ） and displayed different molecular weight distribution pattern. The protective effects of hydrolysates on the freeze-induced denaturation of myofibrillar protein （Mf） from bighead carp （Aristichthys nobilis） mince during storage at -20℃ for 12 weeks were investigated. The hydrolysate （5 % dried weight/wet weight） reduced the freeze-induced denaturation of Mf as evidenced by the lowered decrease in Ca-ATPase activity and reactive sulfllydryl contents as well as the impeded increase in surface hydrophobicity. Microscopic photographs indicated that the hydrolysates inhibited the growth of ice crystal in fish mince, and then prevented the aggregation of Mf during frozen storage. The protective effects of hydrolysates on freeze-induced denaturation of Mf were influenced by the molecular weight distribution. PPH had strongest cryoprotective ability among three hydrolysates.

Purification and Identification of Antioxidant Peptides from the Scallop Skirts of Mimachlamys Nobilis

The processes of scallop meats can produce a large amount of by-products like scallop skirts,which are rich in nutrients. This work aimed to obtain the information about antioxidant peptides derived from scallop skirts of Mimachlamys nobilis. The hydro-lysates obtained by trypsin exhibited the highest antioxidant activity( 75.6%,79.5% and 76.7% using DPPH,hydroxyl and superoxide anion radical scavenging activity assays,respectively). The antioxidant peptides( MNAP) were separated and purified using UF membranes,GFC processes and RP-HPLC,and the antioxidant activity of MNAP was identified to be 85.7% using DPPH radical scavenging activity assay. The peptides( MNAP) were composed of two peptides with their molecular weights2 855.6 Da and 3 007.2 Da using MALDI-TOF-MS,respectively. The results suggested that the scallop skirts of Mimachlamys nobilis could be explored as a source of antioxidant peptides.

Study on the Tripolyphosphatase (TPPase) Property of Bighead Carp (Aristichthys nobilis) Myosin Subfragment-1

Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30℃ and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2+ was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2+ under low concentrations, but was inhibited when the concentration was over 17 mmolL-1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL-1 under the condition of 17 mmolL-1 Mg2+. The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2 mmolL-1.

Antioxidant and Antimicrobial Activities of Essential Oils Extracted from Laurus nobilis L.Leaves by Using Solvent-Free Microwave and Hydrodistillation

In this study, laurel essential oils were obtained by using solvent-free microwave extraction (SFME) and hydrodistillation (HD) methods from Laurus nobilis leaves and determined their antioxidant and antimicrobial activity. Extraction time was reduced by about 43% in SFME at 622 W and 67% in SFME at 249 W compared to hydrodistillation. Essential oil of laurel was extracted by SFME at 622 W (100%) and 249 W (40%) power levels and HD inhibited oxidation generated by ABTS radical by 93.88%, 94.13% and 92.06%, respectively. Trolox equivalent antioxidant capacities (TEAC) of essential oils were 0.18 mM/mL oil for SFME at 622 W, 1.36 mM/mL oil for SFME at 249 W and 2.40 mM/mL oil for HD (p < 0.05). Essential oils of L. nobilis were extracted by SFME at 100% and 40% power levels and HD inhibited linoleic acid peroxidation by 70.57%, 63.53% and 89.18% respectively. Inhibition effects of laurel essential oils obtained by SFME at different power levels and HD on DPPH radical cation oxidation were not significantly different. The strongest antioxidant activity against DPPH radical was found in the essential oil obtained by SFME at 100% power level. Essential oils displayed antimicrobial activity against Staphylococcus aureus 6538P, Escherichia coli O157:H7 and Salmonella typhimurium NRRL E 4463 except for Listeria monocytogenes. The inhibitory effect on Staphylococcus aureus 6538P survival of laurel oil obtained from SFME by using lower power level was found to be lower than that obtained from SFME at 100% power level and HD

Genetic Diversity of Three Aristichthys nobilis Populations and One Inbreeding Stock

Genetic diversity of threeAristichthys nobilis populations and one inbreeding stock was studied using random amplified polymorphic DNA (RAPD) method. Materials of natural populations were collected from two counties of Guangxi Province, Hengxian (NH) and Shanglin (NS) and one city of Hubei Province, Wuhan city. (NW). Shanglin and Hengxian's river system respectively belongs to Qianjiang and Yujiang River, two tributaries confluencing to Xunjiang River, main tributary of Xijiang River, which is the biggest tributary of the Zhujiang River system, and Wuhan's water system belongs to the Yangtse River system. The inbreeding stock (RS) was the more than 10 generation descendant by brother-sister mating system whose parents were collected from Shanglin. The results showed that the genetic variety of individuals of RS was very low (0.105 4), whereas that of natural populations was relatively high, which from high to low was 0.158 1 (NW), 0.132 0 (NH) and 0.110 5 (NS). As an index for genetic distance pair-wise populations, the genetic variety between populations was studied, which characterized the genetic distance between populations. The genetic distance of NW and NH, NW and NS, NW and RS were respectively high, whereas that of NH and NS, NS and RS, NH and RS was low. Chi-test (χ 2) and the analysis of the genetic variety pair-wise populations was taken as efficient approach for studying population difference.

Index Design and Comprehensive Evaluation of Germplasm Resources of Fruits Based on Mathematical Model of AHP and FCE:Sterculia nobilis Smith as a Case

The mathematical model of analytic hierarchy process(AHP)-fuzzy comprehensive evaluation(FCE)was applied to comprehensively evaluate the germplasm resources of Sterculia nobilis Smith,and the scientific nature and reliability of the mathematical model was verified by calculating index weights and comprehensive evaluation scores.In this paper,11 indicators were selected to construct a comprehensive evaluation system from four dimensions of yields,resistances,contents of main inclusions in seeds and tree shapes.AHP method was applied to calculate the index weight of each dimension,after passing the consistency test,FCE method was applied to comprehensively evaluate germplasm resources of S.nobilis Smith.The index weights of the yields,resistances,contents of major inclusions in seeds and tree shapes were 0.5518,0.2554,0.1279 and 0.0649,respectively.The yield had the greatest influence on the comprehensive evaluation of germplasm resources of S.nobilis Smith,which was in line with the actual production demand of S.nobilis Smith as a food crop.However,resistances and contents of major inclusions in seeds had limited influence on it,while tree shapes had the least influence on it.After fuzzy comprehensive evaluation,the final evaluation score was 88.00,the corresponding evaluation score was between 4 and 5,and the evaluation results ranged from slight good to good,which indicated that the evaluation weights corresponding to the four dimensions were more scientific and reasonable.In this study,the mathematical model of AHP-FCE was used to establish and evaluate the comprehensive evaluation system of the germplasm resources of S.nobilis Smith.According to the values of index weights and the evaluation results,it showed that the mathematical model was scientific and reliable,and it could provide a new reference method for the comprehensive evaluation of germplasm resources of other fruits.

Phytochemical Profile of Wollemia nobilis Half-Matured Female Cones and Their Potential Ethnopharmacological and Nutraceutical Activities

In this work, the half-matured female cones of the rare species, Wollemia nobilis, were studied for their phytochemical profile for the first time. Fourteen compounds were isolated and identified by means of column chromatography, Nuclear Magnetic Resonance （NMR） spectroscopy and Mass Spectrometry （MS）. In particular, these compounds were acetyl-isocupressic acid （1）, methyl-（E）-communate （2）, sandaracopimaric acid （3）, wollemol （4）, 7″-O-methyl-agathisflavone （5）, 7,4″-di-O-methyl-agathisflavone （6）, shikimic acid （7）, quinic acid （8）, glucose （9）, sucrose （10）, raffinose （11）, D-lactic acid （12）, succinic acid （13） and alanine （14）. The chemotaxonomic implications of their presence were discussed and a preliminary phytochemical comparison between these cones and the male ones was also performed. This evidenced several similarities but also some differences that were widely treated about. Moreover, a preliminary nutraceutical evaluation of these cones, based on phytochemistry, was carried out. Actually, this showed a good nutraceutical potentiality of the half-matured cones but also some potential critical state mainly due to the occurrence of acetyl-isocupressic acid （1）, which is quite known to have some adverse pharmacological effects. For this reason, more in-depth nutraceutical studies would be necessary to exactly determine the ethnopharmacological and nutraceutical value of these cones.

Antibiotic Activity of the Essential Oil of Laurel （Laurus nobilis L,） on Eight Bacterial Strains

The recent studies unveil more and more therapeutic properties of the essential oil of Bay leaf （Laurus nobilis L.）. The aim of this study is to determine the chromatographic profile of the essential oil of Bay leaf cultivated under the climatic conditions of the Algerian East and to test its antibiotic activity, against 8 bacterial strains （Escherichia coil, Serratia sp., Proteus sp., Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus D, Pseudomonas aeruginosa and Acinetobacter baumanii）, by using different concentrations. The GC/MS analysis showed that the essential oil is rich in eucalyptol （35.31%）, [3 linalool （22.52%）, eugenol methyl ether （9.17%）, camphene （7.37%） and 3 carene （5.39%）. The antibiotic activity of the essential oil was determined by the diffusion on agar method. Measuring diameters of inhibition method of Vincent [1] indicated that bacterial strains which are very sensitive to even very diluted essential oil are Pseudomonas aeruginosa, Streptococcus D, Serratia sp. and Klebsiella pneumoniae. Staphylococcus aureus, E. coli and Acinetobacter baumanii exhibit less sensitivity and Proteus sp. is especially sensitive to the pure oil. Laurus nobilis L. is a Mediterranean endemic that presents an interesting antibacterial activity and its culture should be encouraged and expanded in Algeria.

In vitro Axillary Bud Multiplication of Citrus Nobilis Lour. in Indonesia

This research aimed to get the best composition ofcytokinin （BAP） and auxin （NAA） concentration on in vitro axillary bud multiplication of Tawangmangu orange （Citrus nobilis Lour.）. The research was conducted in Plant Physiology and Biotechnology Laboratory of Agriculture Faculty, Sebelas Maret University Surakarta from February 2008 to September 2008, used factorial design with two factors based on Completely Random Design. The first factor was BAP concentration consisting of five levels： 0, 0.5, 1, 1.5, 2 ppm and the second factor was NAA concentration consisting of five levels： 0, 0.5, 1, 1.5, 2 ppm. So there were 25 combination treatments, each of them was repeated for three times. The result observation data of shoot initiation time and number of shoot were analyzed with analysis of variance and if significant continued with Duncan＇s Multiple Range Test at 5% level. Data of shoot color and amount of leaves were analyzed descriptively. The result showed that there was interaction between BAP and NAA on shoot initiation time. Combination of 0.5 ppm BAP and 1.5 ppm NAA was able to accelerate the shoot initiation time and produced the largest number of leaves that was eight leaves. BAP was able to increase the number of shoots. Average largest amount of shoot on 0.5 ppm BAP treatment was 3.93 shoots/explant. The dominant color of leaves was light green.

Seasonal Variation in Volatile Oil, Polyphenol Content and Antioxidant Activity in Extract of Laurus nobilis Grown in Iran

The leaves ofLaurus nobilis were collected in the middle of four seasons （spring, summer, autumn, and winter） to determine the best harvesting time for obtaining the highest oil yield, 1,8-cineole and polyphenol content and antioxidant activity. After drying the plant materials in shade, their EOs （essential oils） were obtained by hydro-distillation method. Analysis of variance showed harvesting time had significant effect on the oil yields of L. nobilis. Seventy one components were identified in the oils of L. nobilis with 1, 8-cineole （5.7%-42.6%）, ot-terpinyl acetate （3.2%-13.1%）, sabinene （2.3%-12.0%）, beta-elemene （0.2%-17.7%） and （E）-caryophyllene （0.2%-16.9%） as the main constituents in different seasons. The predominant phenolic constituents in L. nobilis were cinnamic acid, carvacrol, quercetin and coumarin, respectively. Gallic acid, catechin, caffeic acid, chloregenic acid, p-Comaric acid and rutin were not detected in any seasons. The best antioxidant activity was in spring （268.6μg/mL） and the lowest one was in winter （702.1μg/mL）.

Characterization of stmn1a and genetic effects of a 22-bp Indel in its promoter region of bighead carp Hypophthalmichthys nobilis

Stathmin 1(stmn1)gene,which is involved in the control of cell cycle progression,cell proliferation,differentiation and motility,is a crucial relay in the signal transduction of multiple signaling pathways.Reports on the function of stmn1 in fish are scarce.In this study,the characterization and function of stmn1a gene were explored in an important food fish,namely bighead carp(Hypophthalmichthys nobilis).The bighead carp stmn1a(Hynstmn1a)genomic sequence,which has 2995 bp with an ORF of 447 bp,is evolutionarily conserved in teleost fish.The highest level of expression of Hynstmn1a is in the un-fertilized eggs and spleen of adult bighead carp.The overexpression of Hynstmn1a facilitates cell cycle progression and suppresses apoptosis in EPC cells.In an siRNA assay,disruption of stmn1a in EPC cells resulted in the inhibition of cell cycle progression and promotion of apoptosis.Analysis of promoter activity indicated that an upstream transcription factor(foxo4)regulates Hynstmn1a.Zebrafish mutants with stmn1a knockout by CRISPR/Cas9 exhibited a significant retardation of body length(p<0.05).There was no significant difference in body weight between stmn1a-mutant zebrafish and wildtype(p=0.053).A 22-bp Indel in the promoter region of Hynstmn1a with an observed heterozygosity(Ho)of 0.136 in a bighead carp population(n=191).The polymorphism of this 22-bp Indel genotype is significantly associated with body length(BL),head length(HL)(p<0.05),body weight(BW),head height(HH),and head width(HW)(p<0.01),showing its genetic effects on growth promotion.This study sheds light on the function of stmn1a in fish and demonstrates the potential of the 22-bp Indel of Hynstmn1a as a gene marker when selecting breeding individuals for faster growth and a bigger head of bighead carp in aquaculture.

鳙鱼(Aristi chthys nobilis)的胚胎发育

前言对魚类的养殖和研究,在周朝末年已有历史記載。唐代以皇室姓李,詔民不得养鯉,于是青、草、鰱、鱅、四大家魚便成了我国人民养殖的主要对象。在唐代290年間,我們祖先积累了丰富的养殖經驗,搞出了一整套完善的捞苗、运苗和养苗的方法,宋代周密又总結了前人的方法,写記在“癸辛杂識”里,至今仍有其重要意义。解放后,由于党和毛主席的英明領导,淡水养殖业有了巨大的发展。特別是从1958年大跃进以来,关于魚类的野外調查、专題論文和綜合性討論等方面的研究均有很大的成就。鰱、鱅魚的人工催产、人工受精和人工孵化的研究,先后在广东和浙江試驗成功,本省也于1962年获得了成功。

华贵栉孔扇贝主要经济性状对闭壳肌重的影响效果分析

闭壳肌是华贵栉孔扇贝Chlamys nobilis(Reeve)的产品形式,它的大小成为选择育种的一个重要目标性状,由于其不易测性给选育工作带来困难。采用多元回归和通径分析来了解各经济性状对闭壳肌重的影响程度,从而找出与闭壳肌重的关联度最大的性状作为选育目标性状是本研究的目的。随机挑取同一养殖群体中的152只1龄华贵栉孔扇贝,对其壳长、壳高、壳宽、铰合线长、活体重、软体部重和闭壳肌重等7个性状进行测定并计算性状间的相关系数。以闭壳肌重为依变量,其它性状为自变量进行多元回归和通径分析,计算出对应的通径系数和决定系数。结果表明,7个性状间的相关系数均达到极显著水平(P<0.01);通径分析表明软体部重对闭壳肌重的直接影响最大(0.712),其次是壳宽(0.394),其它经济性状对闭壳肌重的影响是通过软体部重、壳宽来间接实现的;决定系数分析表明其结果与通径分析呈现一致的变化趋势。经多元回归分析,逐步剔除偏回归系数不显著的壳高和铰合线长,建立了壳长、壳宽、活体重和软体部重对闭壳肌重的回归方程:Y=-4.403+0.032X1+0.243X2-0.035X3+0.228X4,R2=0.856。本研究为华贵栉孔扇贝的选择育种提供理论依据。

温度与盐度对华贵栉孔扇贝幼贝存活与生长的互作效应研究

在室内实验条件下,采用二因素五水平的正交实验方案,设置了5个温度梯度(15、19、23、27、31℃)和5个盐度梯度(18、22、26、30、34),研究了温度与盐度对华贵栉孔扇贝幼贝存活与生长的互作效应。结果表明:(1)华贵栉孔扇贝在最适盐度范围内,幼贝适宜的存活温度为15.0～30.5℃;最适存活温度19.0～27.0℃;适宜生长温度15.0～30.4℃,最适生长温度23.3～27.9℃。在最适温度范围内,幼贝适宜的存活盐度为20.3～34.0;最适存活盐度27.9～34.0;适宜生长盐度19.3～34.0,最适生长盐度21.9～34.0。(2)温度和盐度对幼贝存活和生长的影响存在互作效应。当盐度处于最适宜范围时,幼贝的适宜及最适温度范围达到最大;当盐度向两个极端移动时,幼贝的适宜及最适温度范围变小;但是适宜及最适温度范围的中心点不会随盐度的改变而改变。当温度处于最适宜范围时,幼贝的适宜及最适盐度范围达到最大;当温度向两个极端移动时,幼贝的适宜及最适盐度范围变小;但是适宜及最适盐度范围的中心点不会随温度的改变而改变。(3)幼贝对低温的适应能力强于对高温的适应能力,对高盐的适应能力强于对低盐的适应能力。

鳙目标强度和行为特征的水声学研究

使用EY60回声探测仪于2010年5月10—15日、9月28—29日分别对5种不同体长规格的鳙进行了目标强度及昼夜行为的现场测定。结果显示:鳙的全长范围为30.05～80.00 cm,体长范围为25.10～68.80 cm,体重范围为0.3～6.0 kg,对应的有效目标强度范围为-51.84～-42.06 dB,最大目标强度范围为-47.53～-37.06 dB。鳙的目标强度(TS)与其全长、体长、体重的对数值(logBL、logTL、logW)线性回归关系均显著(P<0.01);平均有效目标强度回归方程标准误为0.55～0.61 dB,较最大目标强度回归方程更为准确。另外,鳙的平均游动速度为0.15 m/s,且有明显的昼夜垂直移动规律。

金鳙和黑鳙的肌肉营养成分分析及评价

采用国标(GB)检测方法,依据FAO/WHO的评价规定,对2010年发现于常德珊珀湖后经人工选育的金鳙和2015~2016年采样于常德珊泊湖的黑鳙(Aristichthys nobilis)进行肌肉营养成分分析和评价。结果表明,金鳙肌肉鲜样的水分、粗蛋白、粗脂肪、灰分水平分别为76.1%、20.6%、0.52%、1.1%,黑鳙的相应指标为76%、19.8%、0.48%、1.2%,其中两者间粗脂肪含量有显著性差异。金鳙和黑鳙的肌肉干样中17种氨基酸总含量分别为88.69 g/100 g和87.68 g/100 g、鱼类必需氨基酸含量为43.2 g/100 g和42.63 g/100 g、呈味氨基酸含量为32.52 g/100 g和32.32 g/100 g,没有显著性差异。两者肌肉氨基酸含量高低的排序也一致,含量最高的均为Glu,其次为Asp、Lys、Leu,含量最低的为Pro;必需氨基酸中含量最高的是Lys、Leu,最低的是Met。两种鳙鱼间除2种含硫氨基酸(Met、Cys)和组氨酸(His)含量有显著性差异外,其他氨基酸含量基本一致。从AAS和CS评分值可见,两者的限制性氨基酸均为Val、Ile或Thr。两者的必需氨基酸指数(EAAI)为80.47和80.13。研究说明,人工选育的金鳙具有与天然水域鳙鱼相当的营养品质。

贵阳红枫湖鲢、鳙的食性研究

鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)是滤食性鱼类,具有净化水体的作用。从2007年开始,贵阳市每年向红枫湖投放500万鲢、鳙进行水体富营养化的治理。为了分析红枫湖鲢、鳙对饵料资源的利用情况,在2010年10-11月研究了鲢、鳙的摄食强度,在2011年5-6月研究了鲢、鳙的摄食强度、食物组成及比例等方面。结果表明:鲢、鳙的总摄食率分别为98.00%、96.93%;冬季鲢、鳙的饱满指数范围分别为44.13～99.79%、46.12～127.00%,春季鲢、鳙的饱满指数范围为53.27～245.14%、49.94～234.32%,鲢、鳙春季的饱满指数显著高于冬季。在食物组成上,鲢的肠道有36种藻类,鳙的肠道有31种藻类。从个数比例来看,鲢、鳙食物中浮游植物占个数组成比例的99%以上,浮游动物很少;但从重量比例来看,浮游动物在鲢、鳙体内分别占(50.993±2.214)%、(90.799±2.321)%。选择性指数E表明鲢对蓝藻门的浮游植物有较大的选择性。