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大多数水产饲料制造商使用挤压膨化系统生产水产饲料 ,首先要考虑饲料的物理特性 ,如 :淀粉熟化度、浮料或沉料、油脂含量、产品尺寸和外观等 ,他们也必须考虑如何操控膨化加工过程。1饲料特性1 .1 淀粉熟化度淀粉熟化度受到淀粉的种类、研磨颗粒大小和加工条件的影响 ,膨化机的运转操作对淀粉熟化度也有很大的影响 ,膨化过程中增加额定机械能 (SME)可大幅提高淀粉熟化度 (参见图 1 )。图 1额定机械能和淀粉熟化度的关联性1 .2 沉料或浮料鱼类好食浮料或沉料 ,依不同鱼类特性而变化 ,因进食方式不同影响饲料效率。若鱼类食用饲料较慢 ,… 相似文献
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Ronald W. Hardy 《中国水产》2009,(5):87-88
三．鲑鳟鱼类膨化饲料之开发
膨化饲料的制造是将湿的原料混合后加热至100—150℃在压力下挤出膨化,然后将饲料水分干燥至10％以下。饲料水分在膨化机内为液态,当饲料经由模孔挤出时压力下降使得水分瞬间转变为蒸气。这个现象使饲料颗粒迅速膨胀,密度下降成为浮性饲料。原料混合物的差异、水分含量以及膨化条件的方式,膨化饲料的密度可被改变而使下沉速率增快、减缓或甚至浮在水面。 相似文献
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本文通过浮性膨化饲料、沉性硬颗粒饲料、浮性膨化饲料与沉性硬颗粒饲料混合三种不同方法培育鱼种的试验,进行了鱼苗的生长速度、水质情况、饵料系数、经济效益的比较,得出采用浮性膨化饲料培育在上述指标中较其它二种方法有明显优势的结论。生长速度:浮性膨化饲料>沉性硬颗粒饲料>浮性膨化饲料与沉性硬颗粒饲料混合;水质情况:浮性膨化饲料优于沉性硬颗粒饲料优于浮性膨化饲料与沉性硬颗粒饲料混合;饵料系数:浮性膨化饲料<沉性硬颗粒饲料<浮性膨化饲料与沉性硬颗粒饲料混合;经济效益:浮性膨化饲料高于沉性硬颗粒饲料高于浮性膨化饲料与沉性硬颗粒饲料混合。 相似文献
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水产养殖业的饲料往往要求有特定的性状、在水中具有高度的稳定性、易于观察鱼类采食、不污染水质；尽可能提高饲料的转化率、减少传统的硬颗粒饲料存在易散失、易污染水体等的弊端———这也是为了适应当前人们对环境保护的要求。膨化浮性料是目前水产常规品种养殖降本增效的首选饲料品种。一、水产膨化浮性料的优点膨化浮性饲料有利于提高饲料利用率。膨化料提高物料淀粉的糊化度，破坏和软化纤维结构的细胞壁，使蛋白质变性，脂肪稳定，有利于消化吸收。同时脂肪从颗粒内部渗至表面，使饲料具有特殊的香味，提高适口性。硬颗粒料或粉状的… 相似文献
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实验将加州鲈(Micropterus salmoides)鱼苗用膨化浮性饲料养成商品鱼,对膨化浮性饲料养殖加州鲈生产效果进行了分析。结果显示:在114 d鱼种养殖期内,加州鲈从5 g长至112 g,比预定的出塘规格(100 g)高出12%,饵料系数为1.14,表明鱼种阶段,加州鲈对膨化饲料有良好的反应。在159 d商品鱼养殖期内,加州鲈从155 g长至354 g,生长缓慢,平均饵料系数为1.43。 相似文献
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采用同一营养水平的饲料配方,试制了非膨化沉性硬颗粒饲料和膨化浮性颗粒饲料(简称非膨化饲料和膨化饲料)。设非膨化饲料、膨化饲料和膨化与非膨化饲料混合投喂三个处理组(A非膨化饲料组; B膨化饲料组; C非膨化饲料∶膨化饲料=1∶1组)。每个处理三个平行,网箱养殖。结果:三个处理组,增重率、特定生长率、肥满度等均有差异;全鱼营养成分、水分、蛋白质和灰分含量差异不显著;脂肪含量差异显著。结果表明:膨化饲料喂养草鱼生长速度更快,肥满度较大;而非膨化饲料喂养的草鱼脂肪含量更低,肥满度相对较小;混合投喂介于两者之间。因此,草鱼养殖户可根据市场需求选择不同加工方式的饲料投喂。 相似文献
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试验采用胃蛋白酶-胰蛋白酶两步法和β-淀粉酶法分别测定饲料蛋白质体外消化率和淀粉糊化度,探讨了膨化工艺参数对二者的影响。结果表明：物料水分含量、喂料速度、螺杆转速和机筒温度的适度增加都使淀粉糊化度、蛋白质体外消化率增大;机筒温度过高反而使蛋白质体外消化率减小。适宜的膨化条件为：调质后水分26%-30%,喂料速度30-60 r/min,螺杆转速150-250 r/min,机筒温度120-135℃。在此条件下,饲料的淀粉糊化度为90%-92%,蛋白质体外消化率为90%-92%。 相似文献
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The effects of exogenous digestive enzyme supplements on the digestibility of wheat starch or diets containing either wheat or dehulled lupin (Lupinus angustifolius var. gungurra) by silver perch (Bidyanus bidyanus) were investigated. In the first experiment, Natustarch® (α‐amylase supplement specific to starch) was added at three nominal concentrations (0, 50, 100 or 150 mg kg?1 diet) to diets containing either raw or 100% gelatinized wheat starch (30% dietary inclusion content) and fed to silver perch. The apparent digestibility coefficients (ADCs) for dry matter, starch and energy were calculated. The action of Natustarch® on the diet and in the digestive tract was also investigated. The addition of Natustarch® to diets containing raw and gelatinized wheat starch led to an average increase in reducing sugar content of diets of 67% and 340% respectively, indicating that the α‐amylase was more efficient at hydrolysing wheat starch in the gelatinized form. Gelatinized wheat starch was digested more efficiently than raw wheat starch. However, although the addition of Natustarch® at ≥ 50 mg kg?1 led to a significant increase in digestibility of raw wheat starch; the digestibility of gelatinized wheat starch, which was already high, was not further improved. Leaching due to immersion in water caused a minor loss of α‐amylase activity from diet pellets treated with Natustarch® (～ 13% after 5 min). The α‐amylase activity in the anterior section of the intestinal tract of silver perch fed diets containing Natustarch® was not affected, indicating that the α‐amylase had been denatured by the acidic conditions in the stomach of silver perch. In the second experiment, diets containing wheat or lupin (at the 30% inclusion content) were treated with Natugrain‐blend®[an enzyme supplement containing β‐glucanase and β‐xylanase, specific to non‐starch polysaccharides (NSPs)] at three nominal concentrations (0, 75, 150 or 300 μL kg?1) and fed to silver perch. ADCs for energy and protein were calculated. The addition of Natugrain‐blend® had no effect on dry matter, energy or protein digestibility of the diets or ingredients. 相似文献
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模仿自然繁殖条件下的黄鳝人工繁殖试验 总被引：10，自引：1，他引：9
黄鳝(Monopterus albus)属合鳃目,合鳃科,黄鳝属,是我国重要的经济鱼类之一,受环境污染及滥捕的影响,自然资源量不断下降。而人工养殖因受苗种繁殖的制约,尚难以形成规模。我国鱼类学家伍献文和刘建康等曾对黄鳝的生殖习性和幼体变态作过研究,国内外许多学者对黄鳝性逆转等方面亦作过许多报道,但有关黄鳝人工繁殖的报道却不多。由于黄鳝属吐泡营巢繁殖的鱼类,且怀卵量低,一般黄鳝在繁殖期间,黄鳝先在水表面吐泡沫,做成泡沫巢,然后雌鳝在水中产卵,与此同时,雄鳝即排精,精液将卵子托于泡沫巢中,受精卵在泡沫巢中 相似文献
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Wild‐catch eels with low fat content are either not accepted at all or accepted as a lower‐quality and less valuable product in the global eel market. This study was undertaken with the goal of increasing the fat content of yellow shortfin eel, Anguilla australis (104 ± 11 g initial weight), captured in the wild and kept in captivity for a short period, as well as assessing their rate of growth. An 86‐d feeding trial was conducted indoors in a recirculation aquaculture system, at 25.5 ± 1.6 C. Two commercial extruded dry feeds were tested; one formulated for European eel and one not specifically intended for use on eels. Good values of specific growth rate (1.10 and 1.12%/d) and feed conversion ratio (1.01 and 1.10) were achieved with both tested feeds. At the end of the trial, eels achieved 20–22% total fat, starting from wild fish with 7% fat content. Fat quality of the fattened eel was appreciably superior (higher proportion of omega‐3 fatty acids) than the fat of eels captured in the wild. The results of this study are encouraging for the prospect of fattening yellow shortfin eels and obtaining a market‐oriented eel product. 相似文献
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Robert Vassallo-Agius Takeshi Watanabe Hitoshi Imaizumi Tetsuo Yamazaki Shuichi Satoh Viswanath Kiron 《Fisheries Science》2001,67(4):667-674
ABSTRACT: This study was conducted to investigate the effect of squid meal and astaxanthin in dry pellets on the spawning performance of striped jack. Two groups of 8-year-old fish with an average bodyweight of 3.5 ± 0.4 kg were used. The control group was fed a raw fish mix (RF) and the experimental group was fed steam dry pellets (as-DP) containing 10 p.p.m. astaxanthin and squid meal, the latter replacing half the fish meal. Each group was fed once a day, three times a week in floating net cages for a period of 5 months. Seven females and seven males were selected from each group and transferred to 65 m3 indoor concrete tanks for spawning, where they were kept at optimum spawning conditions (22°C) for 1 month. The average bodyweights of selected fish were 3.8 ± 0.5 kg and 3.8 ± 0.6 kg for the RF and as-DP groups, respectively. Both groups spawned a total of 18 times and the mean total egg production and egg quality, measured in terms of buoyancy, fertilization and hatching rates, showed no significant differences ( P > 0.05) between groups. Total larval production was 679.9 × 103 and 678.1 × 103 larvae/kg-female for the RF and as-DP groups, respectively. These results show that the combination of astaxanthin and squid meal in dry pellets for striped jack broodstock improved the overall spawning performance to a level similar to that of fish fed on RF. 相似文献
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Effect of squid meal in dry pellets on the spawning performance of striped jack Pseudocaranx dentex 总被引：1，自引：0，他引：1
Robert Vassallo-Agius Hitoshi Imaizumi Takeshi Watanabe Tetsuo Yamazaki Shuichi Satoh Viswanath Kiron 《Fisheries Science》2001,67(2):271-280
SUMMARY: This study was carried out to investigate the effects of dietary squid meal or a combination of squid meal and krill meal as part of the protein source in dry pellets on the spawning of striped jack Pseudocaranx dentex . Five months prior to spawning, 7-year-old fish were divided into three groups of 10 fish each (male : female ratio, 5 : 5). The control group was fed a raw fish mix (RF) and the other two groups were fed either steam-dry pellets with squid meal replacing 50% of their fish meal (fs-DP) or steam-dry pellets containing equal proportions of fish, squid and krill meals (fsk-DP). Feeding was carried out once every other day in 5 × 5 × 5 m floating net cages and the fish were transferred to 65 m3 indoor tanks for spawning. Eggs and yolksac larvae produced were evaluated for their quality and those obtained during the first 2 weeks of spawning were sampled for chemical analysis. The fish had an average bodyweight of 3.5 ± 0.4 kg at spawning. Although egg production of the RF group was significantly higher ( P < 0.05) than that of the dry pellet groups, the fs-DP group produced the best quality eggs with higher fertilization and hatching rates. The fsk-DP group had the lowest egg production and quality. Lipid classes and fatty acid compositions of eggs and yolksac larvae were dependent on the broodstock diets. These results show that the combination of fish meal and squid meal in dry pellets for striped jack improved egg quality but not production whereas the combination of fish meal, squid meal and krill meal was not effective. 相似文献
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Sparus aurata were cultured during an 8-month period in brackish water (salinity about 25 ppt) in an extensive culture system comprising eight earthen ponds, each with a water surface of 2.1 ha. Initial mean wet weight of fish in all ponds varied from 13.6 ± 1.9 to 19.2 ± 2.6 g/fish. The eight ponds were randomly allocated one of four experimental treatments (two ponds/treatment). In the first treatment, ponds were fertilized monthly with 100 kg urea and 50 kg triple super phosphate. The other treatments (2–4) were fed a locally produced tilapia pellet feed containing 25% crude protein made using different processes. Fish in the second treatment were fed tilapia feed pelleted by compressing machine, whereas in treatments 3 and 4 the pellets were produced by extruder machine (Wenger). Pellets in treatment 3 were floating and in the fourth were semi-sinking. Fish were fed pellets twice daily at 6% of their biomass. The mean final body weight for each treatment respectively was 104.6, 118.9, 156.8 and 158 g. Specific growth rate (SGR) of 0.8, 0.79, 0.99 and 0.95%/day, were obtained in ponds using only inorganic fertilizer, compressed sinking pellets, extruded floating pellets and extruded semi-sinking pellets, respectively. Feed conversion ratios (FCR) for treatments with the extruded tilapia pellets were 2.2 and 2.6 g feed/g gain, which were significantly (P < 0.05) better than treatments with compressed pellets (3.2 g feed/g gain). Production/ha/year were 1389, 1358, 945 and 682 kg fish for the groups fed with extruded floating, extruded semi-sinking, compressed and natural food, respectively. Under the present experimental circumstances, Sparus aurata fed extruded floating tilapia pellets (25% crude protein and 2,600 kcal/g), showed the best productive performance. 相似文献
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为了解日本鳗鲡玻璃鳗的早期营养需求，分别对中国近海6个不同地点玻璃鳗体组织一般营养成分、氨基酸和脂肪酸含量进行了分析。结果显示，野生玻璃鳗体组织中水分含量为78.62%±2.03%，干重基础下粗蛋白质含量为69.08%±0.64%、粗脂肪含量为11.96%±1.33%、粗灰分含量为11.45%±1.30%。在台州、舟山、南通和东台4个采样点的样品中，水分含量无显著差异，而粗蛋白含量以舟山点最高、粗脂肪含量最低，并且舟山点样品肠道内发现可见内容物。玻璃鳗样品中氨基酸含量以谷氨酸、天门冬氨酸、赖氨酸、亮氨酸最高，半胱氨酸最低；除舟山点外，各采样点氨基酸含量无明显差异。不同洄游地点玻璃鳗组织中脂肪酸含量均以C16:0、 C18:1n9、 C20:5n3(EPA)、 C22:5n3、 C22:6n3(DHA)为主要成分，其中EPA和DHA共占脂肪酸总量的31.59%±1.00%，不同洄游地点样品必需脂肪酸含量差异明显。研究表明，必需氨基酸、必需脂肪酸对于玻璃鳗的正常生长存活具有重要意义。此外，对比不同地点营养物质组成及稚鱼饵料理论需求量分析，推测舟山点海洋环境中包含更适合玻璃鳗稚鱼摄食的食物，... 相似文献
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Growth, mortality and moulting rate of noble crayfish, Astacus astacus L., juveniles in aquaculture experiments 总被引：1，自引：0，他引：1
Growth, mortality, moulting rate and cheliped loss were examined in aquaculture experiments with noble crayfish, Astacus astacus L., juveniles from four different Norwegian populations in the period September 1987-June 1988. The juveniles were hatched indoors in May 1987 from parents wild-caught in 1986. The experiments were performed at 18-19°C in communal rearing units. Mean total length at experiment start was about 20mm in all groups. There were no significant differences in mean size (final mean total length: 32-2-34-8mm). mortality (83a-900%) or cheliped loss (429-700%) among juveniles from the different populations when exposed to similar conditions (food: dry pellets; photoperiod: L:D = 8:16). Among crayfish fed fish and potatoes in addition to dry pellets, and with continuous light conditions, mortality was reduced significantly to about 70%. Continuous light conditions significantly increased mean size (final mean length: 36-1-389mm). Moulting occurred from November throughout the experiment period. Moulting rate was positively correlated to mortality and growth rate (i.e. mean length increase). A positive correlation between mortality and cheliped loss, along with direct observations of cannibalism, indicated that agonistic behaviour and cannibalism were the dominating mortality factors. It is suggested that continuous light conditions reduce agonistic behaviour and thereby decrease mortality. 相似文献
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The nutrient losses into the water from rainbow trout (Oncorhynchus mykiss) cage culture using locally caught low-fat Baltic herring, herring-based moist diets and fishmeal-based dry diets were estimated. Feeding with herring led to nitrogen and phosphorus losses into the water twice as high as those feeding with dry pellets (78–162 versus 37–39 g N and 15–39 versus 7–18 g P per kg growth). This was supported by direct measurements of ammonia and phosphate excretion. Increasing feeding frequencies resulted in increased nutrient losses irrespective of diet. Increasing dietary lipid level had a more pronounced effect in reducing the expected nutrient losses in dry pellets than herring. The reduction within the herring was approximately 18% on average for nitrogen and 25% for phosphorus losses. Dietary water content did not affect the nutrient losses. © Rapid Science Ltd. 1998 相似文献
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黄鳝肌肉营养成分的分析 总被引：74，自引：6，他引：74
对黄鳝的稚鳝（体重9.2-15.5g)、幼鳝（体重62.3-76.0g)、小成鳝（体重108.3-121.4g)和大成鳝（体重222.8-242.8g)肌肉中的水分、蛋白质、脂肪含量及脂肪酸、氨基酸的组成进行了分析,结果表明：黄鳝肌肉中的蛋白质含量高达18.79%-19.93%,脂肪含量较低。高度不饱和脂肪酸含量占脂肪酸总量的19.15%,必需氨基酸的含量上中氨基酸总量的40.98%,谷氨酸的含量很高,为氨基酸总量的16.95%。 相似文献