Nutritional quality of Metamysidopsis insularis Brattegard (Crustacea: Mysidacea)

In natural conditions the mysid Metamysidopsis insularis is commonly found in the littoral lagoon of Margarita Island (Venezuela). It is used as live food in the marine fish culture. However, its nutritional quality is not well documented. In the present study we analysed the nutritional value (total protein, carbohydrate and lipids profile) of M. insularis. The mysids were collected in La Restinga lagoon (Margarita Island, Venezuela). Levels of total proteins, lipids and carbohydrates were 700 ± 28.5, 160 ± 13.9 and 20 ± 0.90 g kg^?1 respectively. The lipids classes were 427 ± 2, 106 ± 98, 287 ± 113 and 179 ± 87 for phospholipids, triglycerides, cholesterol and cholesterol esters respectively. The fatty acids profile, determined by gas chromatography, showed important concentration of fatty acids for the metabolism of marine organism, such as 16:0, 18:0, 18:2n‐6, 18:3n‐3, 18:4‐3, 20:5n‐3 and 22:6n‐3; attaining levels of 27.49% in PUFA n‐3 and 2.92% in n‐6. The relation of eicosapentaenoic acid/docosahexaenoic acid was 2.1 ± 0.15. The results support the use of M. insularis as food for species of fish and crustaceans under culture conditions.     

Water quality,production parameters and nutritional condition of Litopenaeus vannamei (Boone, 1931) grown intensively in zero water exchange mesocosms with artificial substrates

The effect of artificial substrates on the water quality, production parameters and nutritional condition was assessed in experimental intensive cultures of Litopenaeus vannamei grown in mesocosm units with zero water exchange. The initial stocking densities in triplicate 1000 L tanks were 600 and 800 g of juvenile shrimp (2.7 g) per unit, with (W) and without (WO) artificial substrates. There were no significant differences between the water quality parameters of the four treatments. In the tanks with the lower stocking biomass, the best survival (96.7% vs. 87.0%), growth rate (1.69 vs. 1.35 g week⁻¹), final biomass (1969.6 vs. 1516.0 g m³) and feed conversion ratio (1.30 vs. 1.90) were obtained with artificial substrates. Similar results were observed for the higher stocking biomass (90.9% vs. 74.5%, 1.50 vs. 1.13 g week⁻¹, 2221.6 vs. 1560.8 g m³, and 1.50 vs. 2.60 respectively). The nutritional condition of shrimp was improved using artificial substrates. The protein content in muscle was higher (21.6% and 20.4%) in ponds with substrates as compared with the control (21.2% and 15.9%).     

六个群体翘嘴红鲐肌肉生化组成的比较

比较分析了中国六群体翘嘴红鲐（Culter alburnus）的肌肉生化组成。试验材料分别取自太湖、兴凯湖、梁子湖、浮桥河水库和南湾水库五个野生群体，以及由太湖野生群体经人工驯养、繁殖数代获得的养殖群体。分析结果表明，各群体之间翘嘴红鲐肌肉的水分、灰分和粗蛋白含量差异不显著（P〉0．05）。而养殖群体的粗脂肪含量显著高于其它五个野生群体（P〈0．05）。南湾水库群体的多不饱和脂肪酸和必需脂肪酸含量均最高，必需脂肪酸含量由高到低依次为南湾水库群体〉浮桥河水库群体〉兴凯湖群体〉梁子湖群体〉养殖群体〉太湖群体。氨基酸总含量由高到低依次为：太湖群体〉兴凯湖群体〉南湾水库群体〉梁子湖群体〉浮桥河水库群体〉养殖群体，而必需氨基酸含量的高低顺序为：太湖群体〉兴凯湖群体〉梁子湖群体〉南湾水库群体〉浮桥河水库群体〉养殖群体。相比之下，太湖群体的必需氨基酸指数（EAAI）最高，其次依次为：南湾水库群体〉梁子湖群体〉兴凯湖群体〉浮桥河水库群体〉养殖群体。各群体的大多数必需氨基酸氨基酸分（AAS）和化学分（CS）均大于1，仅兴凯湖群体的赖氨酸、苯丙氨酸＋酪氨酸的AAS低于1，养殖群体的赖氨酸和缬氨酸的AAS和赖氨酸、蛋氨酸＋半胱氨酸、苯丙氨酸＋酪氨酸和缬氨酸的CS小于1，而成为各自的限制性氨基酸。综合所得的结果，野生群体的肌肉营养品质明显优于养殖群体，而野生群体中太湖、兴凯湖和南湾水库群体的肌肉品质相对较优。     

Effects of live prey availability on growth and survival in the early stages of cuttlefish Sepia officinalis (Linnaeus, 1758) life cycle

This investigation examined the effects of live prey availability on growth and survival of Sepia officinalis. Two independent experiments, comprising two feed rations each, were performed, using adequate prey size. In the first experiment, cuttlefish hatchlings were fed live mysids, Paramysis nouvelli [(feed ratio I (fr I)], at 15% body weight per day (bw day^?1) (fr I₁₅) and 30% bw day^?1 (fr I₃₀). In the second experiment, juvenile cuttlefish were fed live Atlantic ditch shrimp, Paleomonetes varians (fr II), under the same experimental design. In both experiments, the final mean weight, feeding rate and instantaneous growth rate were higher when animals were fed feed ratio fr II₁₅ and fr II₃₀ (30% bw day^?1). The results indicate that prey availability influenced weight gain, irrespective of the prey used, during the first 2 months of cuttlefish life cycle. This effect seems to be more noticeable when a certain limit of prey is achieved. For cuttlefish fed fr II, the optimal prey density is thought to be under 2.5 g prey L^?1 (i.e. 14 shrimp L^?1). Results indicate that cuttlefish can withstand prey densities up to 120 mysids L^?1 for cuttlefish up to 3 weeks old and 19 shrimps L^?1 for cuttlefish up to 6 weeks old.     

饲喂不同水平虫草培养残基对中华绒螯蟹营养品质的影响

在基础饲料中分别添加0.25％、0.5％、1.0％、2.0％、4.0％、8.0％、16.0％的蛹虫草培养残基(简称虫草基),以基础饲料为对照,饲喂规格为(4.0±1.0)g的中华绒螯蟹75 d,测定中华绒螯蟹(Eriocheir sinensis)常规营养成分、肌肉与血清氨基酸及肝胰腺脂肪酸含量,研究虫草基对中华绒螯蟹营养品质的影响.结果显示:(1)虫草基对中华绒螯蟹水分和蛋白含量无影响(P＞0.05),0.5％和1.0％添加组的全蟹、肌肉、肝胰腺粗脂肪含量显著高于对照组(P＜0.05).(2)适量添加虫草基可增加中华绒螯蟹肌肉游离氨基酸含量,0.5％ ～2.0％的添加组显著高于对照组(P＜0.05),但对氨基酸组成及主要呈味氨基酸含量影响不显著(P＞0.05);1.0％和16.0％添加组中华绒螯蟹血清氨基酸和主要呈味氨基酸含量明显提高(P＜0.05).(3)虫草基的添加可提高肝胰腺不饱和脂肪酸及必需脂肪酸含量,且1.0％添加组显著高于对照组(P＜0.05).饲料中添加适量的虫草基可提高中华绒螯蟹肌肉与血清的游离氨基酸、血清必需氨基酸、肝胰腺不饱和脂肪酸和必需脂肪酸含量,从而改善中华绒螯蟹营养品质.     

Partial replacement of fish oil by flaxseed oil in Atlantic halibut (Hippoglossus hippoglossus L.) diets: effects on growth,nutritional and sensory quality

Three isonitrogenous (520 g protein kg^?1 DM) and isoenergetic (25 MJ kg^?1 DM) diets containing increasing levels of flaxseed oil (FxO; 0%, 40% and 70% of total added oil) at the expense of fish oil (FO) were tested for 33 weeks in groups of 61 individually PIT‐tagged halibut (initial weight, 849 ± 99 g). Effects on fish growth performance, fillet nutritional and sensory quality were determined. Specific growth rate (0.2% day^?1), feed conversion ratio (1.2–1.3) and nitrogen and energy retention were not affected by dietary treatments. Dietary fatty acid composition was reflected in fatty acid profiles of halibut muscle, liver and heart. Muscle of fish fed FxO diets contained higher 18:2n‐6 and 18:3n‐3 concentrations whereas 20:5n‐3 and 22:6n‐3 levels were significantly reduced. However, increasing FO replacement induced preferential retention of 22:6n‐3 especially in heart, and a trend for 20:5n‐3 conservation in heart and muscle was observed. FO replacement did not affect colour, texture and the characteristic fish odour and flavour of cooked fillets. By selectively retaining long‐chain polyunsaturated fatty acids halibut can adapt to a lower dietary supply without adverse effects on growth, feed conversion ratio, survival, and fillet nutritional and sensory quality.     

福建南日岛东岱村北部海域夏秋冬海水水质营养状况分析评价

2012-2013年,根据夏秋冬三个季度3个航次海水水质的监测结果,对福建南日岛东岱村北部海域夏秋冬海水水质营养状况进行分析与评价。结果表明,南日岛东部东岱村北部海域海水水质良好,无机氮、化学需氧量及石油类符合国家一类海水水质标准,无机磷则在2013年2月航次监测中达到三类海水水质标准,海区富磷现象明显。总体而言,该海域海水处于健康状态,能够满足野生坛紫菜生长要求。     

Evaluation of silver perch (Bidyanus bidyanus, Mitchell) nutritional requirements during grow-out with high and low protein diets at two feeding levels

Silver perch (Bidyanus bidyanus, Mitchell) of 65 g average weight were reared at high density under controlled conditions on diets containing 24.8% and 40.6% protein. Diets were fed at 2% or 4% of the fish biomass day^?1. Both protein concentrations and feeding level of the diet influenced growth and proximate composition of the fish at the end of the 50‐day growth trial. Energy requirement for maintenance for these fish was found to be 77 cal BW^?0.8 and for each unit of energy retained 3.78 cal BW^?0.8 needed to be supplied, and for each gram of protein retained per metabolic body weight 5.04 g were required. The results indicate that it is possible to obtain the same weight increment when feeding a 24.8% protein diet at a level of 4% body weight day^?1 as compared with only 2% body weight day^?1 of a 40.6% protein diet. This study indicates that the nutritional requirements for early grow‐out are similar to those found in a previous study with juvenile silver perch and adds information concerning the required relationships between dietary amino acids. The results provide information required for further refinement of nutrition for this species.     

Field evaluation of live chilling with CO2 on stunning Atlantic salmon (Salmo salar) and the subsequent effect on quality

Atlantic salmon were slaughtered in three ways on a commercial slaughter line: (1) killed by a percussive stun after crowding; (2) killed by percussive stun after crowding, pumping and live chilling; (3) killed by exsanguination after crowding, pumping and live chilling. The live‐chilled fish were exposed to seawater (2°C) saturated with carbon dioxide (pH 5.5–5.7) for 40 min. The fish were calm after live chilling, but not unconscious, as eye rolling was observed in all individuals. Subsequent exsanguination of the unstunned fish resulted in death. Both rapid live chilling and the subsequent exsanguination appeared stressful to the fish, as a large and rapid pH drop coupled with earlier onset of rigor mortis, indicative of high muscle activity during the process were observed. The muscle core temperature during ice storage showed that live chilling only has an effect on carcass temperature during the first 6 h post mortem. After 6 h, no significant differences in temperature were detected between live‐chilled and traditionally ice‐chilled fish. We conclude that commercial use of live chilling in combination with high levels of CO₂ does not stun Atlantic salmon. Live chilling followed by exsanguination of the unstunned fish appears to be highly stressful and should be avoided.     

活水产品暂养及运输中的营养品质下降与安全问题初探

随着国民生活水平的提高,水产养殖业的不断发展,人们对水产品的消费也越来越多。同时,现代消费者的食品营养与安全意识日益增强,对水产品的质量也有了更高的要求,不再满足于冰鲜和冷冻水产品。大量活鲜的鱼类、虾类、蟹类、贝类源源不断地从产地销往全国各地。野生或养殖的活鲜     

生态化池塘养殖模式下凡纳滨对虾与日本囊对虾营养成分的比较

对生态化池塘养殖模式下凡纳滨对虾(Litopenaeus vannamei)与日本囊对虾(Marsupenaeus japonicus)肌肉营养成分与营养品质进行了分析比较。结果表明:该养殖模式下,凡纳滨对虾的水分、粗蛋白、粗脂肪和粗灰分含量与日本囊对虾相近。两种对虾均呈现高蛋白、低脂肪的营养特点;均含有18种氨基酸,呈味氨基酸占氨基酸总量的百分比分别为(29.29±0.16)%、(29.01±0.19)%,必需氨基酸指数(EAAI)分别为68.57、67.90,其构成比例符合FAO/WHO的标准,且凡纳滨对虾的蛋白质营养价值略高于日本囊对虾;两种对虾的水溶性维生素和钙、铁、锌、硒等无机元素含量都十分丰富。综上,生态化池塘养殖的凡纳滨对虾和日本囊对虾肌肉营养价值均非常高,为优质的动物蛋白食品。     

Effect of different chilling rates for cold anaesthetization of Penaeus monodon (Fabricius) on the survival, duration and sensory quality under live storage in chilled sawdust

The present work was carried out with a view of determining the chilling rates for cold anaesthetization and live storage of Penaeus monodon (Fabricius) in chilled sawdust, for live transportation. Three chilling rates of 1.38 ± 0.16 °C h^?1 within 8 h (slow), 2.76 ± 0.32 °C h^?1 within 4 h (moderate) and 5.52 ± 0.64 °C h^?1 within 2 h (fast) were tested to cold anaesthetize 144 farm‐raised P. monodon (22–25 g) in each chilling rate at 15 g L^?1 salinity, from 25 °C down to 14 ± 1 °C in plastic net boxes kept in a refrigerated chilling tank provided with aeration. Eight cold‐anaesthetized shrimps subjected to each chilling rate were packed in an insulated cardboard box (triplicate) between two layers of moist and chilled (2–3 °C) sawdust, and kept inside a chilled storage cabinet at 14 ± 1 °C for durations of 16, 20, 24, 28, 32 and 36 h. Survival was determined by revitalizing the shrimps in aerated water with an initial temperature of 20 °C, which was raised to 28 ± 1 °C at 2.7 °C h^?1 within 3 h. Statistically valid, safe durations for obtaining 100% survival were 22.9 ± 1.1, 19.1 ± 0.4 and 14.6 ± 1.1 h, using probit analysis at the slow, moderate and fast chilling rates respectively. The weight loss (1.5–8.8%) due to cold anaesthetization and subsequent revitalization of the packed shrimp was insignificant. Sensory evaluation showed significant improvement in general appearance, and also in colour as well as in flavour of the meat when compared with that of the freshly harvested dead shrimps. The texture as well as odour of the raw and cooked meat between treated and untreated shrimps was unaffected. The effects of chilling rates and shipping durations on sensory quality were insignificant. One hundred per cent survival was obtained for 24, 20 and 16 h for the slow, moderate and fast chilling rates respectively. Percentage survival of the shrimps at different durations was significantly different among the chilling rates, but pair‐wise comparison revealed that the slow and moderate chilling rates were identical. Hence, the moderate chilling rate, which took only 4 h, can be considered the optimum, though the choice of different chilling rates depends on the duration of live storage desired.     

Effects of postharvest processes on quality of Australian sardines (Sardinops sagax) and redbait (Emmelichthys nitidus nitidus) for feeding aquacultured southern bluefin tuna (Thunnus maccoyii)

Feed nutritional quality impacts on the performance of aquacultured species. This study was undertaken to assess the consequences of existing postharvest handling practices on nutritional quality of local baitfish (Australian sardines, Sardinops sagax and redbait, Emmelichthys nitidus nitidus) used to feed farmed southern bluefin tuna (Thunnus maccoyii). Controlled experiments were then undertaken to determine the most appropriate postharvest treatments to maintain baitfish nutritional quality, assessed through measurement of vitamins C and E, histamine, K value and TBARS. During frozen storage (?18 °C) vitamins and fish freshness decreased significantly and rancidity increased; after approximately 3 months baitfish were of questionable utility, particularly as a source of antioxidants. On‐land freezing method [i.e. block or individually quick frozen (IQF)] affected vitamin E loss with IQF sardines losing vitamin E faster than block‐frozen baitfish. Block‐frozen baitfish, particularly sardines, should be thawed in seawater, not air or freshwater, to minimize vitamin losses. Thawing time should be no more than 2 days, and baitfish storage less than 3 months. Thiobarbituric acid reactive substances (TBARS) correlated well with remaining vitamin E, indicating its usefulness as an indicator of antioxidant status. TBARS analysis is methodologically simpler, faster and cheaper than that for vitamins, and is therefore recommended for determination of baitfish nutritional quality.     

Exploring the potential of providing and feeding pikeperch larvae (Sander lucioperca L.) with euryhaline copepod nauplii: A zoo technical trial

Egg hatching and nauplii success from three euryhaline calanoid copepod species at low salinities suggest a promising alternative initial live feed for pikeperch (Sander lucioperca L.) to the conventional live feed. Acartia bifilosa and Eurytemora affinis are viable candidates with egg hatching down to zero salinity, and Acartia tonsa nauplii survive up to 2 h at zero salinity after transfer from low-salinity seawater. When offered A. tonsa and Artemia, pikeperch larvae equally consumed both prey types. We suggest that euryhaline copepods can be a supplement to or even a substitute for the normal live feed currently used as larval feed for pikeperch.     

糙齿海豚营养组成分析

主要就中国水域糙齿海豚肌肉组织的营养组成情况进行分析。分析部位包括背肌、腹肌和尾肌3个部分。分析结果表明,海豚肌肉组织粗营养成分中腹肌脂肪含量最高,背肌粗蛋白含量最高。肌肉中氨基酸组成具有极高的一致性,含量最高的氨基酸均为谷氨酸,最低的是胱氨酸。海豚肌肉组织脂肪酸组成含有动物及鱼油中典型的脂肪酸如棕榈酸(16:0)、棕榈油酸(16:1)、硬脂酸(18:0)、油酸(18:1)、EPA(20:5ω-3)及DHA(22:6ω-3)。饱和脂肪酸(SFA)的总量与单不饱和脂肪酸(MUFA)的总量相近且大于多不饱和脂肪酸(PUFA)的总量。不饱和脂肪酸中ω-3/ω-6的比值较低(0.12～1.36),与其它海洋有机生物相比(通常高于4,有的高达50),该值明显偏低。海豚肌肉组织中富含钙(Ca)、镁(Mg)、铁(Fe)及锌(Zn)、铜(Cu)、锰(Mn)、硒(Se)等微量元素,这些元素在海豚肌肉组织中的分布无明显差别。     

长江口凤鲚雌雄成体营养成分分析与比较

对长江口雌性和雄性成体凤鲚(Coilia mystus)整体的营养成分和品质进行了分析与评价。结果显示,雌、雄凤鲚整体水分、粗蛋白、粗脂肪和灰分的质量分数分别为78.36%±1.41%、76.70%±1.20%,14.25%±1.05%、15.18%±0.12%,4.61%±1.78%、4.84%±0.27%和2.22%±0.38%、2.97%±0.64%,雌、雄间均不具有显著性差异(P0.05)。雌、雄均含有18种组成蛋白质的氨基酸,总量分别为66.20%±5.78%和65.93%±6.35%(质量分数,干样),其中8种必需氨基酸(EAA)总量分别是25.07%±1.93%和23.95%±2.21%,两者间不具有显著性差异(P0.05),分别占氨基酸总量的37.90%和36.33%,雌、雄凤鲚的必需氨基酸组成比例均符合FAO/WHO的标准。色氨酸是雌、雄凤鲚整体的第一限制性氨基酸,蛋氨酸+胱氨酸是第二限制性氨基酸,雌、雄凤鲚整体的EAAI分别为70.73和66.99,4种鲜味氨基酸总量分别为25.99%±2.53%和26.02%±2.3%(质量分数,干样)。雌性凤鲚的饱和脂肪酸(SFA)含量显著低于雄性(P0.05),而多不饱和脂肪酸(PUFA)含量则显著高于雄性(P0.05),单不饱和脂肪酸(MUFA)两者无显著差异(P0.05)。雌性凤鲚脂肪酸中EPA与DHA质量分数分别为5.70%±0.24%和10.15%±1.31%,显著高于雄性凤鲚的1.05%±0.40%和1.06%±0.44%。结果表明,长江口雌、雄成体凤鲚整体的氨基酸较均衡,而雌性凤鲚的脂肪酸营养更为丰富,比雄性凤鲚具有更好的食用价值与保健作用。     

Size measurement and nutritional condition evaluation methods in sandfish (Holothuria scabra Jaeger)

The aims of this study were to establish an accurate size measurement method and a nutritional condition evaluation method of Holothuria scabra (Jaeger). Although 0.5% KCl and 0.05% MgSO₄ did not induce anaesthesia, 2% menthol–ethanol for 20 min was found to be effective and harmless. The anaesthetization significantly reduced the coefficient of variation of the mean body length and weight by 68% and 43% respectively. During starvation, body size and weight decreased concomitantly, resulting in an unchanged condition factor (body weight/volume), suggesting that the condition factor cannot be used as an index of nutritional condition. Protein, cholesterol and carbohydrate concentrations in the body fluid were analysed to study the relationship with starvation. As the protein and cholesterol concentrations initially increased and then decreased during the starvation period, it is difficult to use them as an index of nutritional condition. The carbohydrate concentration showed a gradual one‐fold increase during 10 days of starvation, and it may be used as a proxy for nutritional condition; however, further physiological studies are needed. Body fluid density and volume relative to body size gradually increased and decreased, respectively, during starvation. These methods may be used to correctly monitor the conditions of H. scabra in studies for aquaculture and stock enhancement techniques.     

刀鲚两种生态类群-“江刀”和“海刀”鱼肉营养组成的比较及品质的评价

采用常规方法对刀鲚两种生态类群("江刀"和"海刀")的鱼肉营养成分进行了分析比较并评价了鱼肉品质。结果表明,"江刀"鱼肉粗脂肪含量显著高于"海刀"(P<0.01),是"海刀"的2.03倍,而粗蛋白、水分、灰分含量则低于"海刀"。"江刀"和"海刀"鱼肉的水解氨基酸组成基本一致,均含有18种氨基酸,总量分别占鱼肉鲜样的11.55%和15.37%,其中7种EAA(Leu、Ile、Phe、Try、Thr、Val、Lys)、1种HEAA(Arg)和4种NEAA(Glu、Ser、Tyr、Pro)的含量在"江刀"与"海刀"间存在显著性差异(P<0.05),8种人体必需氨基酸含量分别占鲜样的4.87%和6.4%,与非必需氨基酸的比值分别为85.59%、83.44%,其必需氨基酸构成比例符合FAO/WHO的标准。另外,必需氨基酸指数(EAAI)分别为22.32、41.82,支链氨基酸与芳香族氨基酸的比值(F值)分别为2.43、2.49,4种鲜味氨基酸含量分别占鲜样的4.59%、6.12%;"江刀"鱼肉鲜样中牛磺酸含量(265.43 mg/100 g)显著高于"海刀"(200.93 mg/100 g)。采用甲酯化法衍生化"江刀"、"海刀",再经GC/MS分析鉴定出20种脂肪酸,其中饱和脂肪酸(SFA)9种,单不饱和脂肪酸(MUFA)5种,多不饱和脂肪酸(PUFA)6种。"江刀"多不饱和脂肪酸(9.05%)显著低于"海刀"(13.20%),其中"江刀"EPA与DHA(4.21%、2.26%)显著低于"海刀"(6.71%、2.92%),但绝对含量显著高于"海刀"(P<0.05);ω3PUFA/ω6PUFA值分别为2.67和2.87。全鱼肉中矿物质含量丰富,尤其是Se,Na、Mg、Se的含量在"江刀"和"海刀"之间均存在明显的差异。本研究结果将为刀鲚种质标准的建立和两种生态类群的鉴别提供科学依据。     

Biochemical indices (RNA/DNA ratio and protein content) in studying the nutritional status of Ruditapes decussatus (Linnaeus 1758) juveniles

In this work, we investigated the nutritional status of Ruditapes decussatus juveniles under different rearing conditions, using biochemical indices (RNA/DNA ratio and protein content) and the linear instantaneous growth rate (IGR). Two experiments were conducted to study the effect of starvation, addition of substrate (sand) as rearing support and diet composition on somatic growth and biochemical indices. Results show that biochemical indices of fed juveniles were significantly (P<0.05) higher. Highest RNA/DNA values and protein content were recorded in fed juveniles reared with substrate (P<0.05); conversely, lowest values were recorded in starved ones reared without substrate. In the second experiment, the highest RNA/DNA ratio was recorded in juveniles fed with control algal mixture composed of species commonly used in bivalve nurseries [Isochrysis galbana (clone T-Iso), Chaetoceros calcitrans and Tetraselmis suecica] and lowest in those fed with algal species isolated from Tunisian coasts. This confirms the usefulness of the RNA/DNA ratio and protein content in the clam's nutritional status evaluation. This assay is useful to provide information about the nutritional status and health of the clam in field conditions.     

杂交青虾“太湖1号”肌肉营养成分分析

本试验以池塘养殖太湖青虾为对照,对杂交青虾"太湖1号"营养成分进行了分析。结果显示:杂交青虾"太湖1号"肌肉的水分、粗灰分、粗脂肪、粗蛋白含量与对照组差异不显著(P>0.05)。实验组与对照组氨基酸总量分别为79.5%和80.84%,差异不显著(P>0.05);必需氨基酸指数(EAAI)分别为66.32%和66.94%,构成比例符合联合国粮农组织/世界卫生组织(FAO/WHO)的标准,差异不显著(P>0.05);脂肪酸中EPA和DHA总量分别为0.83%和1.74%,差异不显著(P>0.05);主要微量元素比例合理,与对照组差异不显著(P>0.05)。研究表明,杂交青虾"太湖1号"肌肉主要营养成分与太湖青虾基本一致,两者没有显著差异。