Summertime and early autumn activity of some enzymes in the carbohydrate and fatty acid metabolism of the crucian carp

In June, July, and September the activities of five enzymes involved in the carbohydrate and fatty acid metabolism, namely phosphofructokinase (PFK), lactate dehydrogenase (LDH), citrate synthase (CS), cytochrome oxidase (cyt ox) and 3-hydroxy-acyl-CoA dehydrogenase (HAD), were measured in the heart, liver, red muscle, white muscle, and gill lamellae of crucian carp (Carassius carassius). LDH activity was measured in both reducing (LDHr) and oxidizing (LDHo) directions.The PFK activity in red and white muscle increased significantly between July and September indicating a preparation to winter anoxia by an increased glycylytic capacity in these organs. The HAD activity of the liver had increased significantly (by more than 50%) by September, also a preparation to winter anoxia as HAD is used in the reversed -oxidation (chain elongation of fatty acids). The LDHr and cyt ox activities in the heart and white muscle were highest in July. This shows that both the anaerobic and aerobic capacities are elevated in mid-summer when water temperature is high and oxygen concentration of the water could fluctuate greatly. The LDHo and CS activities in gill lamellae were lowest in July. The results show that the metabolism of crucian carp is under seasonal influence and that a preparation to winter hypoxia/anoxia could be detected in September.     

Application of Azotobacter enhances pond productivity and fish biomass in still water ponds

Two strains (derepressed-nitrogen fixing, Mac-27 and phosphate solubilizing, PS-21) of Azotobacter chroococcum were inoculated in fish culture ponds, singly and in combination with inorganic fertilizers (urea, single superphosphate–SSP). Physico-chemical parameters of pond waters, plankton production and fish biomass were studied. Inoculation of A. chroococcum (Mac-27) enhanced nitrogenase activity and rate of nitrogen fixation. A slight reduction in nitrogen fixation and nitrogenase activity was noticed when urea at 96 kg ha–1 y–1 was mixed with the biofertilizer (Mac-27). Inoculation of PS-21 enhanced phosphate solubilization, but Kjeldahl-nitrogen concentration values remained low in comparison with controls. On the other hand, inoculation of Azotobacter (either strain) enhanced the accumulation of ammonium-N, nitrite-N and nitrate-N. A significant (p < 0.05) reduction in dissolved oxygen (DO) concentration also took place when Azotobacter (both Mac-27 and PS-21) was inoculated in fish ponds. However, when used along with inorganic fertilizers, the reduction was not significant. The pH values were only slightly lowered when the phosphate-solubilizing strain (PS-21) of Azotobacter was inoculated. Inoculation of biofertilizer enhanced plankton production, net primary productivity and fish biomass. However, highest values in most of these parameters were noticed only in ponds that were treated with the higher doses of inorganic fertilizers (urea 192 kg and SSP 1500 kg ha–1 y–1). © Rapid Science Ltd. 1998     

体重和温度对草鱼摄食小浮萍的影响

研究草鱼(Ctenopharyngodon idella)对浮萍的摄食能力及主要影响因素,为合理利用草鱼控制小江回水区浮萍暴发提供依据。草鱼(体重29.7~491.2 g)取自红安县中海农业科技有限公司渔场,小浮萍种源采自重庆市云阳县高阳镇黄莲坝库湾。在试验室条件下研究了草鱼对小浮萍的最大摄食量、最大摄食率与体重和温度的关系。结果表明,在水温(25.82±0.57)℃条件下,随着体重的增加(40.36~478.17 g),草鱼的最大摄食量增大,但最大摄食率呈减小的趋势,两者与体重的相关关系分别为C_(max)=2.460W~(0.779),FR_(max)=246.0W~(-0.221);水温(16.55~30.50℃)对草鱼的最大摄食量和最大摄食率的影响极显著(P0.01),最大摄食量和最大摄食率与水温的回归方程分别为C_(max)=0.074T~(2.045),FR_(max)=0.164T~(1.940);建立的预测不同温度和体重条件下草鱼对小浮萍最大摄食率的模型为:FR_(max)=0.410T~(1.940)W~(-0.221)。     

Microsatellite marker isolation and cultured strain identification in <Emphasis Type="Italic">Carassius auratus gibelio</Emphasis>

Microsatellites have become the preferred molecular markers for strain selection and genetic breeding in fish. In this study a total of 105 microsatellites were isolated and identified in gibel carp (Carassius auratus gibelio) by microsatellite sequence searches in GenBank and other databases and by screening and sequencing of positive clones from the genomic library enriched for AG and GATA repeats. Moreover, nineteen microsatellites were randomly selected to design locus-specific primer pairs, and these were successfully used to identify and discriminate different cultured strains of gibel carp including strains A, D, L, and F. Three different types of microsatellite pattern were distinguished by the number and length of fragments amplified from the 19 primer pairs, and some microsatellite primer pairs were found to produce different microsatellite patterns among strains and strain-specific fragments. In addition, some duplicated alleles were also detected in two microsatellite patterns. Therefore, the current study provides direct molecular markers to discriminate among different cultured strains for selective breeding and aquaculture practice of gibel carp.     

异育银鲫耗氧率和窒息点的研究

为了解昼夜变化、体重及水温对异育银鲫耗氧量、耗氧率和窒息点的影响,应用流水呼吸室法和静水呼吸室法分别测定异育银鲫在不同条件下的耗氧量,结果表明：异育银鲫日间平均耗氧高于夜间平均耗氧,耗氧量随体重增加而增加,呈显著正相关关系;而耗氧率和窒息点随体重增加而减少,呈显著负相关关系,耗氧量、耗氧率、窒息点随水温增加而增加,呈正相关关系。     

温度对鲫血液生化指标和消化酶的影响

采用室内模拟方法,研究了鲫（Carassius auratus）在9 ℃、16 ℃、25 ℃、30 ℃四个温度条件下的血液学指标和消化酶活力的变化。结果显示,鲫血清无机成分中的镁、磷以显著差异在16 ℃时存在最大值,而其他成分变化不显著。在9~25 ℃水温范围内,甘油三脂、总胆固醇、总蛋白、白蛋白、球蛋白等均随水温上升而上升,并在25 ℃时达到最大值,而超过25 ℃后,甘油三脂、总胆固醇、总蛋白、白蛋白、球蛋白等含量均随水温升高而下降。在9~30 ℃水温范围内,血清中谷丙转氨酶和谷草转氨酶活性随水温上升先上升后有下降,在25 ℃时达到最大值。鲫肠道中,蛋白酶和脂肪酶活性在9~25 ℃阶段升高,25~30 ℃时下降,蛋白酶和脂肪酶的活性均在25 ℃时最高;而肝胰脏中蛋白酶和脂肪酶活性随温度变化不明显。     

利用GoldenGate分析的高通量SNP芯片对鲤基因进行分型

单核苷酸多态性(SNPs)标记在大多数物种基因组中数量巨大且分布均匀,是许多水产物种遗传研究的理想标记,因此快速发展了几种高通量、快速的SNP标记分型平台。本研究利用Golden Gate分析技术对鲤Cyprinus carpio转录组测序的1 536个SNP标记合成了一张中等密度SNP芯片,对5个鲤群体的480份样本进行基因分型。结果表明:1 235个SNP标记成功分型,约占80%;915个标记至少在一个家系中呈现多态性,占74.1%;标记最小等位基因频率(MAF)介于0.05~0.5之间,平均为0.334,其中48.9%的标记最小等位基因频率(MAF)大于平均值;5个群体中SNP标记平均多态性信息含量(PIC)在0.3左右,为中度多态,杂合度为0.010~0.990,平均为0.5左右,暗示群体具有丰富的遗传多态性,育种价值及性状改良潜力很大。本研究分型的多态性SNP标记可广泛应用于遗传多样性研究、标记-性状关联分析以及分子标记辅助育种。     

Constitutive nitric oxide synthase (NOS) activities in big-head carp (Aristichthys nobilis)

Nitric oxide synthase (NOS) is an enzyme that catalyzes the formation of nitric oxide (NO), an important biological messenger from L-arginine. There are considerable evidence showing the expression of NOS in mammalian tissues. Information on distribution of NOS activities in various organs and tissues of fish is rare. Non-functional NOS activities were documented in fish semi-quantitatively either by an indirect nicotine-adenine-dinucleotide-phosphate diaphorase (NADPH-d) activity histochemical staining method or by an immunohistochemical method using a cross-reacting antibody to brain NOS. Report on the functional levels of NOS activities in fish is lacking. This report represent the first attempt to document the functional NOS levels in various fish organs and tissues. Constitutive NOS (cNOS) activities in various organs of big-head carp (Aristichthys nobilis) was measured by a chemiluminescence method with a detection limit as low as 10 mol of NO produced. It was found that constitutive NOS activity was highest in the brain, followed by the intestine, stomach, retina, olfactory lobe, swim bladder, skeletal muscle, heart, kidney, ovary and liver. NOS activity could not be detected in the gill filaments. Omission of NADPH in the reaction mixture caused a 57–100% decrease in cNOS activities. However, omission of arginine in the mixture only caused a 56–87% drop in cNOS activities. When compared with cNOS activities documented from other species, a similar pattern of cNOS activities in the various organs and tissues of big-head carp could be seen.     

顶空固相微萃取气相色谱质谱嗅觉测量联用初探鲢肉的挥发性风味物质

为探明鲢肉挥发性气味特征物质,通过顶空固相微萃取法提取和浓缩了鲢肉中的挥发性物质,并利用气相色谱质谱联用以及气相色谱〖CD*7/9〗嗅觉测量法对气味物质进行了定性分析及气味特征的评价。由8人组成的评价小组通过检测频率法进行嗅觉测量。结果表明,经GCMS分析鉴定得到了29种挥发性气味物质,主要是一些羰基类和醇类化合物,占了总挥发性物质的88%。通过检测频率分析法鉴定出12种化合物具有气味特征,表现为鱼腥、金属、青草、油脂氧化、蘑菇等特征。另外有4种未知物也显示了较强的风味特性,它们协同作用构成了鲢的特殊气味。     

Effects of lysine and methionine supplementation on growth,body composition and digestive function of grass carp (Ctenopharyngodon idella) fed plant protein diets using high‐level canola meal

A 76‐day feeding trial was carried out to evaluate the effects of Lysine and Methionine supplementation on growth and digestive capacity of grass carp (Ctenopharyngodon idella) fed plant protein diets using high‐level canola meal (CM). Fish with initial average weight 103.9 ± 0.6 g were fed three extruded diets. Fish meal (FM) diet was formulated as the normal control with 40 g kg^?1 FM and 300 g kg^?1 CM; CM diet was prepared by replacing all FM with CM (total 340 g kg^?1) without Lys or Met supplementation; CM supplement (CMS) diet was similar to CM diet but was supplemented with essential amino acids (EAA) to ensure the levels of Lys and Met similar to those in the FM diet. Feed intake, feed efficiency and specific growth rate of the grass carp fed CMS and FM diets were similar (P > 0.05), but higher than those of the grass carp fed CM diet (P < 0.05). The hepatosomatic index, relative gut length, intestosomatic index and intestinal folds height were significantly improved in fish fed FM and CMS diets as compared to CM diet (P < 0.05). Lower activities of trypsin, lipase and amylase in hepatopancreas were observed in fish fed CM diet (P < 0.05). Three hundred and forty gram per kilogram CM without Lys or Met supplementation significantly decreased trypsin, lipase and amylase mRNA levels in hepatopancreas (P < 0.05). These results indicated that the high supply of CM (340 g kg^?1) in plant protein (200 g kg^?1 soybean meal and 100 g kg^?1 cottonseed meal) diets decreased digestive ability through decreasing digestive enzyme activities and enzyme gene's expressions of grass carp, and these side effects can be reversed by supplementing Lys and Met. Therefore, CM could be high level used in a plant protein blend‐based extruded diet for grass carp as long as EAA were supplemented.