膨化饲料机的操作技术

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 ,…     

不同形态饲料对稚鳝生长性能和水质的影响

<正>目前，随着集约化养殖的发展，饲料残剩、溶失及其代谢产物的低降解率是影响水产养殖生态环境的主要原因之一，叶元土等(2002)研究发现，养殖生产中投喂的饲料中没有被利用部分沉积于水域环境中，对养殖水域生态环境造成了较大的负担。黄鳝配合饲料在形态上主要经历了粉状、颗粒、膨化颗粒3个阶段。膨化颗粒饲料经过膨化加工工艺，能改善淀粉的糊化度，提高养殖动物对饲料的消化吸收率。     

饲料湖化技术的意义、目的及应用

动物饲料在加工过程中获得必要的糊化度 ,是生产颗粒饲料及膨化饲料的主要目的之一 ,更是衡量各种水产饲料质量的重要指标。其原因主要有以下几点 :1淀粉是各种动物饲料的主要组成成分 ,根据饲喂对象的不同 ,淀粉含量约在 2 5 %～ 80 %之间 ,是动物生长的主要能量源。动物特别是水产动物对这种生淀粉的消化、吸收较差 ,从这个角度来说 ,必须对此进行适当的水热处理 ,使生淀粉的结晶结构获得改变而成为α—淀粉 (糊化淀粉 )。淀粉的糊化过程就是对饲料的熟化过程 ,并以淀粉的糊化度来对此进行量化标定。2由于水产动物的采食特性 ,水产饲料必…     

饲料添加剂在水产动物生长、营养及免疫中的应用进展

饲料添加剂是在基础饲料的生产加工或使用过程中添加微量物质,具有强化基础饲料营养价值,节省饲料成本,提高动物生产性能,改善肌肉品质等作用。目前国内外对饲料添加剂的研究众多,为突出饲料添加剂对水产动物在不同方面的影响,本文综述了饲料添加剂对水产动物生长性能、营养成分及免疫中的应用进展。     

水产养殖节能减排技术

<正>D渔用膨化饲料应用技术技术概况:膨化饲料是将饲料膨化处理后形成一种膨松多孔的饲料。膨化是对物料进行高温高压处理后减压,利用水分瞬时蒸发或物料本身的膨胀特性使物料的某些理化性能改变的一种加工技术,分为气流膨化和挤压膨化。饲料经膨化处理后,使淀粉糊化,蛋白质、脂肪等有机物的长链     

水产人工配合饲料的加工设备

水产养殖中使用的人工配合饲料多种多样，广义上可分为海水饲料和淡水饲料。而按饲喂对象可分为鱼饲料、虾饲料等；按加工方法可分为制粒料、膨胀膨化料和粉料等。水产饲料厂的规划及其工艺设计和产品选型主要取决于当地的实际情况，如饲料源的供应情况，原料的品种和形态，对饲料产品的要求等。本文对水产饲料的主要加工设备作一简单的介绍。     

饲料糊化技术的意义、目的及应用

动物饲料在加工过程中获得必要的糊化度,是生产颗粒饲料及膨化饲料的主要目的之一,更是衡量各种水产饲料质量的重要指标.其原因主要有以下几点: 1.淀粉是各种动物饲料的主要组成成分,根据饲喂对象的不同,淀粉含量约在25%～80%之间,是动物生长的主要能量源.动物特别是水产动物对这种生淀粉的消化、吸收较差,从这个角度来说,必须对此进行适当的水热处理,使生淀粉的结晶结构获得改变而成为α-淀粉(糊化淀粉).     

膨化料—降本增效的水产饲料

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…     

甘蔗渣可作虾颗粒饲料

美国农业部热带水产养殖研究所利用榨糖后的甘蔗渣加工成高蛋白的廉价虾类饲料获得成功。为甘蔗渣的利用和虾类饲料源开辟了一条新途径。其制作工艺是将甘蔗渣烘干后磨细,经膨化处理,取膨化物     

水产养殖膨化饲料生产与应用中的注意事项

膨化饲料，俗称浮性饲料。在膨化过程中由于热、湿、压力和各种机械作用，能使饲料中的淀粉充分糊化，破坏和软化纤维的细胞壁部分，释放营养，使蛋白质变性，脂肪稳定，有利于消化吸收，提高饲料的消化率和利用率。同时特殊的工艺使饲料具有特殊的香味，有利于增加动物的食欲。因此，膨化饲料具有消化性能好，水稳定性强，热敏抗营养素低，投喂管理方便，因而在水产养殖业中越来越受到青睐。     

Evaluation of different starch sources in extruded feed for Atlantic salmon

The aim of the experiment was to investigate the effect of partial or total substitution of wheat flour with oat meal and tapioca starch in extruded salmon feed. A mixture design (simplex centroid mixture design) was used to analyse the effect of starch source on physical quality of extruded feed. Physical quality of the extruded feed was evaluated as cohesiveness, pellet density, axial and radial expansion, durability, hardness, strain at rupture and elastic modulus. Starch sources affected behaviour of the diet formulations during extrusion and caused changes in the physical properties of the extruded products. Significant correlations (P < 0.05) between physical properties and weight fraction of the starch sources allowed the establishment of predictive models. The inclusion of oat meal and tapioca starch in the diet gave extruded feed with a higher porosity and lower oil absorption capacity. The mechanical properties of the extruded feeds were significantly different from each other, most likely due to the complex nature of texture formation with respect to process parameters and properties of ingredients.     

Pea and wheat starch possess different processing characteristics and affect physical quality and viscosity of extruded feed for Atlantic salmon

The aim of the study was to investigate the effect of starch source, retention time in the preconditioner and screw speed (RPM) on physical quality of extruded fish feeds. The experiment was arranged in a three by two by two factorial design using three carbohydrate sources [wheat starch (WS), pea starch (PS) or a combination (WS_PS)], two retention times in the preconditioner [long (120 s) or short (62 s)] and two RPM in the extruder [high (300) or low (220)]. Physical quality was assessed by hardness, diameter, expansion ratio, Holmen durability (HDI), DORIS value (DV), oil absorption capacity, oil leakage and pasting viscosity. The results showed that retention time in the preconditioner only affected HDI and oil leakage. Long retention time improved HDI but caused a greater leakage. Changing screw speed from 220 to 300 RPM gave a greater expansion ratio, improved HDI and oil absorption. PS resulted in higher pasting viscosity, HDI and DV, but a generally lower hardness than WS. To conclude, PS and WS have different processing characteristics, and the conditions need to be adjusted according to the starch source used when producing extruded fish feed.     

Feed processing affected the digestibility of carbohydrate sources for dourado Salminus brasiliensis

Carbohydrate utilization by fish varies with feeding habits and feed processing. Extruded aquafeeds have increased digestibility of carbohydrate sources resulting from the cooking and gelatinization of this nutrient, making it readily available for all aquatic species. This study aimed at determining the effects of extrusion cooking of feeds in the digestibility of different dietary carbohydrate sources for dourado. Isonitrogenous and isoenergetic diets (530 g kg^?1 crude protein and 20.80 MJ kg^?1 gross energy) containing either corn, toasted cassava flour, wheat flour, broken rice, cassava starch, or corn starch, in extruded or pelletized form and added of chromic oxide as inert marker, were fed to groups of juvenile dourado (73.97 ± 12.0 g; n = 40) stocked in 500‐L polyethylene tanks. Extrusion cooking improved the digestibility of energy and/or starch of corn, cassava starch, wheat flour, rice and corn starch (P < 0.05), but did not affect digestibility of toasted cassava flour (P > 0.05). It is thus fair to infer that dourado, despite being a carnivorous species, is properly fit to digest wheat flour, rice and corn starch in natural form.     

A review of the effects of ingredient composition and processing conditions on the physical qualities of extruded high‐energy fish feed as measured by prevailing methods

Feed comprises the biggest cost in intensive fish farming and the quality of feed is therefore important. A vast body of research has been carried out in order to investigate nutritional quality of alternative ingredients. Effects of ingredients on physical quality are seldom included in these investigations. Physical quality of feed varies with ingredient composition and processing condition and may interfere with feed intake, nutrient digestibility and therefore growth performance of the fish. In this review, physical quality of extruded, high energy feed, and how ingredient composition and processing conditions affect the quality will be addressed. Various pellet properties will be discussed and methods used to evaluate physical quality will be reviewed.     

Effects of feed processing method (extrusion and expansion-compression pelleting) on water quality and growth of rainbow trout in a commercial setting

To determine the effects of feed processing method (extrusion or expansion followed by compression pelleting) on feed physicochemical characteristics, fecal stability, water quality, and growth performance in rainbow trout, three types of feed pellets (expanded sinking [EpS], extruded sinking [ExS], extruded floating [ExF]) were prepared, analyzed, and fed to juvenile rainbow trout (initial weight = 285.8 ± 15.2 g) at three feeding rates based on feeding rate curves developed at Snake River Farm (Buhl, Idaho, USA) (median rates [%BW] for feeding rate 1: 0.85; feeding rate 2: 0.95; feeding rate 3: 1.05) for 124 days. Results showed that all feeds had similar chemical composition, but the degree of starch gelatinization (as % of starch) was significantly higher in ExS (90.01 ± 0.26) and ExF (84.82 ± 0.63) than in the EpS (9.09 ± 0.41) feed, which led to extruded feeds having much higher water stability, fecal durability, and lower phosphorus discharge. The ExF feed produced better growth (% increase; 154.4 ± 18.5) and feed conversion (1.06 ± 0.06) compared to EpS (126.3 ± 12.4 and 1.26 ± 0.14) and ExS (121.7 ± 7.8 and 1.22 ± 0.04) in rainbow trout. Growth (% increase) improved as feeding rate increased (feeding rate 1: 125.6 ± 10.3; feeding rate 2: 140.8 ± 16.0), but further improvements were not observed at the highest feeding rate (feeding rate 3: 135.9 ± 22.8). The present study is the first to show that the extrusion process not only produces pellets having better quality than the expansion-compressed pelleting method but also improves fecal size and durability in water, and therefore, use of extruded feeds has the potential to improve waste collection and removal and reduce contribution to pollution in effluent.     

饲料蛋白质水平和加工工艺对克氏原螯虾生长性能、消化力和抗氧化性能的影响

为研究不同蛋白质水平和加工工艺饲料对克氏原螯虾(Procambarus clarkii)生长性能、消化力和抗氧化能力的影响,本研究采用4个蛋白质水平(28%、30%、32%和36%)和2种加工工艺即膨化饲料(EF)和硬颗粒饲料(PF)的4×2双因素实验设计,进行为期13周的养殖实验。结果显示,蛋白质水平和加工工艺对克氏原螯虾增重率和肝体比有显著的交互作用(P<0.05)。主效应结果显示,28%蛋白质可显著提高增重率和特定生长率,EF组的末重和增重率显著高于PF组(P<0.05)。蛋白质水平和加工工艺对肝胰脏的胰蛋白酶和淀粉酶活性有交互作用(P<0.05)。主效应结果显示,肝胰脏的胰蛋白酶、淀粉酶和肠道胰蛋白酶、淀粉酶均在28%蛋白质水平时最高,EF组肝胰脏胰蛋白酶、淀粉酶和肠道胰蛋白酶活力高于PF组(P<0.05)。蛋白质水平和加工工艺对肝胰脏的丙二醛和碱性磷酸酶活性有显著的交互作用(P<0.05)。主效应结果显示,肝胰脏碱性磷酸酶活性以及血清的碱性磷酸酶和酸性磷酸酶均在28%蛋白质水平时最低。PF组肝胰脏丙二醛含量显著低于EF组(P<0.05),碱性磷酸酶活性显著低于EF组(P<0.05)。4种模型(Logistic、Gompertz、Von Bertalanffy和Brody)均能很好地模拟克氏原螯虾体重和体长的生长曲线,拟合度均大于0.97,其中,以Logistic模型拟合克氏原螯虾体重和体长最优,且幂函数可以反映体重和体长之间的关系。综上所述,28%蛋白质水平和膨化加工工艺使克氏原螯虾具有最优的生长性能和消化力,28%蛋白质水平的硬颗粒饲料可提高克氏原螯虾的抗氧化能力。     

Performance factors, body composition and digestion characteristics of gilthead sea bream (Sparus aurata) fed pelleted or extruded diets

The effects of steam pelleting or extrusion of a commercial feed on performance of 2 g (small) and 40 g (large) gilthead sea bream was studied. In addition the apparent digestibility of diets, gastric evacuation time (GET) and trypsin and amylase activities were measured in large fish. Fish size significantly increased protein and energy productive value, body protein and lipid, liver glycogen and liver lipid, however decreased daily growth index, feed intake and feed utilization, body moisture and hepatosomatic index. Extrusion processing decreased feed intake, more strongly for small fish, and increased daily growth index, feed utilization, protein and energy productive value, body protein and lipid. Digestibility of starch and energy increased with extrusion and GET of extruded feed was double that of steam-pelleted conditioned feed (i.e. 544 min versus 284 min). Digestive enzyme activities approached maximum values after 240 min for the pelleted diet, while those of the extruded continued to increase, at higher rates for amylase than trypsin. Pelleted diet indicated higher moisture for stomach digesta, while the moisture of the intestinal precipitate indicated a higher water-binding capacity for the extruded diet. The overall results indicate a better assimilation of the extruded diet, which could result from its prolonged gastric evacuation.     

Utilization of sorghum distillers dried grains in extruded and steam pelleted shrimp diets

Use of distillers dried grain with solubles from sorghum (sDDGS) was studied with respect to processing and physicochemical quality of shrimp feed, followed by growth trials with Litopenaeus vannamei (Pacific white shrimp). Shrimp diets with 0%, 10%, 20%, 30% and 40% sDDGS inclusion, as a replacement for soybean meal, were produced using extrusion and steam pelleting. Bulk density of extruded feed (0.53–0.58 g cm^?3) was lower than that of pelleted feed (0.61–0.65 g cm^?3), although sDDGS level did not have an impact. Finished diets were 100% sinking, with some exceptions in the case of extruded feed. Pellet durability index (89.4–96.3%) had an increasing trend up to 20% and 30% sDDGS for extruded and pelleted diets respectively. Extruded feed had higher degree of gelatinization than pelleted feed, although proportion of gelatinized starch generally decreased with sDDGS level. Water stability (76.2–91.6%) was higher for extruded feed as compared to pelleted feed, and remained unchanged or decreased with sDDGS level. The extruded and pelleted diets were evaluated in two growth trials with L. vannamei for duration of 9 and 6 weeks in 40 and 60 tanks (initial weight 0.36–0.38 g; 10 shrimps per tank) respectively. Significant differences were not observed in final mean weight and survival with respect to sDDGS level, indicating that up to 40% of this novel protein source can be used in feed formulations without affecting the performance of L. vannamei. Comparison of extruded feed with pelleted feed for impact on mean weight and feed conversion ratio did not yield conclusive results.     

臭氧水处理在水产品杀菌保鲜中的应用研究进展

水产品自身带有或贮运期间污染的微生物是导致其腐败变质的主因。为减少微生物对水产品品质影响,延长其货架期,减菌化前处理是减少其加工贮藏过程中微生物污染的关键技术。本文在分析比较水产品常用减菌化处理水的作用机理与主要特点的基础上,重点介绍了臭氧水在水产品杀菌保鲜中的应用研究进展,提出其存在问题与解决办法,阐明将臭氧水与流化冰、气调保鲜及其他保鲜处理技术相结合的优势,并对臭氧水在水产品贮藏加工中的应用前景予以展望。