Effect of Diet Size on Feeding Behavior and Growth of Pacific White Shrimp,Litopenaeus vannamei

Abstract

Six diet sizes, manufactured from crumbling large pellets, were investigated for their effect on the feeding behavior and growth of Pacific white shrimp, Litopenaeus vannamei. These diets containing 44.7% protein and 8.2% lipid were fed to 0.9 g shrimp for a period of eight weeks under indoor controlled laboratory conditions. Shrimp were stocked at a density of 12 animals per 52 L aquarium (50/m²) and were evaluated for feeding behavior, final weight, growth rate, feed conversion ratio (FCR), and survival. Feeding behavior was observed weekly starting at the beginning of the 4th week until the end of the trial. Results indicated that the variation in diet sizes did not produce significant differences in shrimp growth, FCR or survival. However, shrimp feeding behavior (in terms of total attacking incidents during feeding) was significantly different among diet sizes. This shrimp behavior was observed more frequently in aquaria fed larger diet size (3.0 mm pellet) as compared with those fed smaller diet sizes (0.7 mm and 1.2 mm crumbles). When shrimp were fed larger pellets, some of the individuals obstruct other individuals and monopolize the diet. Such “selfish” behavior of shrimp could result in considerable size variation and severe mortality of smaller individuals, which could be the case when shrimp are reared to market size. The effect of diet size on shrimp feeding behavior deserves further investigation and the use of a continuous monitoring device such as a video camera is strongly recommended. Future study should also consider various shrimp and pellet sizes more meaningful to aquaculture producers.     

Manufacturing Different Diet Sizes and Its Effect on Pellet Water Stability and Growth of Three Size Classes of Pacific White Shrimp,Litopenaeus vannamei

Abstract

A feed manufacturing method involving the production of large pellets followed by crumbling to desired diet sizes was used to produce six shrimp diets to determine its effect on growth of three size classes of Pacific white shrimp, Litopenaeus vannamei. The six diets containing 45% protein were 0.7 mm crumble, 1.2 mm crumble, 1.7 mm crumble, 2.2 mm crumble, 2.6 mm crumble, and 3.0 mm pellet. These diets were fed to three size classes of shrimp subjected to a four-week growth trial under indoor laboratory conditions. Stocking density was 12 shrimp/aquarium for size class 1 (1.13iö.01 g), 9 shrimp/aquarium for size class 2 (7.31iö.06 g), and 6 shrimp/aquarium for size class 3 (13.12iö. 10 g). Shrimp were fed three times daily and were evaluated for live weight, growth rate, feed conversion ratio (FCR), and survival. Results for shrimp growth appeared to be affected by diet size and pellet water stability. The effects of diet size, however, were more evident on smaller sized shrimp. Weekly growth rates for class 1 and class 2 shrimp indicated significant responses (P < 0.05) to the effects of diet size, while the class 3 shrimp did not show any significant result. The growth rates for both class 1 and class 2 shrimp were lowest at the smallest diet size (0.7 mm crumble) but differed with respect to highest growth rates. The largest diet (3.0 mm pellets) yielded the highest growth rates for class 1 shrimp, while medium sized feed (2.2 mm crumble) produced the best growth for class 2 shrimp. This could be partly attributed to pellet water stability, which had a direct correlation to diet size (r = 0.97). Smaller diet sizes resulting from crumbling larger pellets tend to have lower water stability. The water stability decreased from 82.5% to 76.3% as the 3.0 mm pellets were reduced to 0.7 mm crumbles. Stress cracks are created during crumbling, and surface area to volume ratio are increased as larger particles are reduced to crumbles. These would make smaller diet particles more susceptible to disintegration and nutrient leaching. For class 3 shrimp, the largest pellets produced the highest growth rate. This high growth value, however, was not significantly different (P > 0.05) from growth results produced by the crumbled feed sizes. This observation suggests that diet sizes ranging from 0.7 mm crumble to 3.0 mm pellet could be used for a 13 g shrimp, although preference would be given to larger pellets due to higher growth performance and better pellet water stability. Results for shrimp live weights were similar to results obtained for weekly growth rates. FCR and survival of all shrimp sizes did not show any significant response from the effects of various diet sizes. However, larger shrimp were less efficient in their diet utilization than smaller shrimp.     

Effect of microencapsulated thyme essential oil on white spot virus-infected <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

The present work was performed to investigate if feeding Litopenaeus vannamei with microencapsulated thyme essential oil (TEM, 1.05 g thyme essential oil per 100-g powder) adsorbed on commercial pellet feed was able to protect shrimps against white spot syndrome virus (WSSV) disease. Five treatments were tested: uninfected shrimp fed with commercial pelleted feed (T_C, negative control), WSSV-infected shrimp fed with commercial pelleted feed (T₁, positive control), WSSV-infected shrimp fed with commercial pelleted feed with 0.1% TEM (T₂), WSSV-infected shrimp fed with commercial pelleted feed with 0.5% TEM (T₃), and WSSV-infected shrimp fed with commercial pelleted feed with 1% TEM (T₄). At 72 h post infection, phenoloxidase activity of shrimps treated with 1% TEM did not show significant differences with T_C values but it was significantly higher than that of the other treatments (T₁, T₂, and T₃). Moreover, shrimps treated with T₄ presented absence of clinical signs of WSSV infection and their survival rate was significantly higher than that of T₁, T₂, and T₃ treatments. Therefore, 1% TEM seemed to protect shrimps against WSSV symptoms. Using microencapsulated thyme essential oil may help to fight against WSSV in shrimp farms.     

渤海小黄鱼摄食习性

根据2009年8月至2011年5月4个航次渤海底拖网调查所获得的样品,采用胃含物分析法、K-W检验和聚类分析等方法,对38～218 mm体长范围小黄鱼(Larimichthys polyactis)的摄食习性及其随体长、季节的变化进行了研究,并探讨了小黄鱼摄食随海域和年际的时空变化。结果表明:渤海小黄鱼摄食的饵料有40余种,主要以鱼类、虾类和浮游动物为食,优势饵料种类为六丝钝尾虾虎鱼(Amblychaeturichthys heaema)、日本鼓虾(Alpheus japonicus)、太平洋磷虾(Euphausia pacifia)、长额刺糠虾(Acanthomysis longirostris)和中华哲水蚤(Calanus sinicus)。渤海小黄鱼在春夏秋这三个季节中,春季的摄食强度最低,夏季和秋季的摄食强度都较高,不同的是夏季摄食率更高,而秋季的摄食量更高。随着体长的增大,渤海小黄鱼的摄食策略发生了相应的变化。从摄食强度分析,在体长较小时,胃饱满指数低,小黄鱼通过高摄食率来提高摄食强度;随着体长的增加,通过高胃饱满指数来提高摄食强度。从摄食的饵料个体分析,小黄鱼采取了随着体长增加摄食饵料个数减少,饵料个体增大的摄食策略。从摄食的饵料组成分析,小黄鱼随着体长增加发生了显著的食性转换现象:体长小于60 mm属浮游动物食性;体长60～99 mm时,属混合动物食性;体长100～119 mm时,属虾食性;体长超过120 mm,包括了虾/鱼食性和鱼食性。小黄鱼摄食的时空变化与环境中优势饵料生物的数量波动密切相关。     

Replacement of Soybean Meal by Lupin Meal in Practical Diets for Juvenile Penaeus monodon

The potential of lupin meal as an alternative protein source to soybean meal in isonitrogenous practical diets for the juvenile black tiger shrimp Penaeus monodon was evaluated through the studies of growth, digestibility and pellet water stability. Five isonitrogenous diets were formulated to contain 40% protein. Protein from dehulled Lupinus albus seed meal replaced 0, 25, 50, 75 and 100% of the protein from defatted soybean in the diets. Juvenile P. monodon (4.35 × 0.31 g) were assigned randomly and fed each test diet at a daily feeding rate of 5 % body weight for 42 d in triplicate tanks equipped with a flow-through sea water system. No statistically significant differences were observed in weight gain, feed intake, feed conversion ratio (FCR), protein conversion efficiency and apparent protein utilization of shrimp fed diets with 0, 25, and 50% replacement. Shrimp fed the diet with total replacement of soybean meal by lupin meal had the poorest performance (P < 0.05) with regard to the above parameters. Survival was similar (87%) for all dietary treatments. The apparent dry matter digestibility and apparent protein digestibility were similar for all diets ranging between 70.5 and 72.8% and 89.7 and 90.8%, respectively. There was no significant difference in whole body composition (dry matter, lipid, protein and ash) of shrimp on the various diets. The poorest pellet water stability was displayed by the diet with 100% replacement while the diet containing a combination of soybean meal and lupin meal (50% replacement) was the most stable. The results have demonstrated that dehulled lupin seed L. albus meal has good potential as a substitute protein source for up to 50% of the protein from defatted soybean meal and could be included up to 17% inclusion level in juvenile P. monodon practical diets with no adverse effects on growth, feed intake, FCR, survival, feed utilization, body composition, and digestibility coefficients of dry matter and protein.     

强壮藻钩虾对中国明对虾与日本囊对虾生长和抗病力的影响

以强壮藻钩虾(以下简称钩虾)作为中国明对虾和日本囊对虾的天然饵料,以对虾人工配合饲料为对照研究钩虾对中国明对虾和日本囊对虾生长和抗病力的影响。对两种规格的中国明对虾[体质量分别为(0.33±0.0204)g和(2.07±0.184)g,分别记为SF组和MF组]和日本囊对虾[体质量为(0.25±0.018 1)g,记为SM组]分别投喂人工配合饲料和钩虾,养殖35 d。结果显示:(1)与人工配合饲料相比钩虾可以提高MF组和SM组对虾的特定生长率和SM组对虾的成活率;(2)钩虾可以显著提高SF组和SM组对虾血细胞总数(P<0.05);(3)钩虾可以显著提高3组对虾血清总蛋白含量(P<0.05)及SF组和SM组血蓝蛋白含量(P<0.05);(4)钩虾可以显著提高日本囊对虾溶菌酶活力(P<0.05);(5)钩虾可以显著提高FM组和SM组对虾酚氧化酶活力和超氧化物歧化酶活力(P<0.05);(6)钩虾可以显著性提高SF组和SM组对虾血清过氧化物酶相对活力(P<0.05);(7)对虾健康指标总得分与其感染WSSV后的100%致死时间关系密切,两者之间呈现一定的线性关系(R2=0.948 9)。研究结果表明,钩虾与对虾人工配合饲料相比可以促进中国明对虾和日本囊对虾的生长及提高对虾抗病力。     

投喂不同饵料对长薄鳅生长的影响

在水温18.6～21.6℃条件下,将初始体质量为(3.91±0.22) g的长薄鳅幼鱼随机分为5组,每组3个重复,每个重复10尾鱼,饲养在圆形玻纤缸(直径1 m、高0.8 m)中,分别投喂刀额新对虾、鳙鱼、配合饲料(粗蛋白≥46.0%)、虾+饲料、鱼+饲料5种饵料,以筛选适宜于长薄鳅幼鱼的适宜饵料投喂模式。75 d的饲养结果表明,不同投喂模式对长薄鳅的存活率无显著性影响(P>0.05),而对长薄鳅的生长影响显著(P<0.05)。试验结果表明,虾组、鱼组、饲料组、鱼+饲料组的长薄鳅最终体质量无显著性差异(P>0.05),但虾+饲料组最终体质量和体质量特定生长率显著高于其他4组(P<0.05),依次为虾+饲料组>饲料组>虾组>鱼组、鱼+饲料组。5个试验组鱼的体长特定生长率无显著性差异(P>0.05),依次为虾+饲料组>虾组>饲料组、鱼+饲料组>鱼组。试验结束时,各试验组鱼的生长离散均有所升高,生长离散变化依次为鱼组>鱼+饲料组>饲料组>虾组>虾+饲料组。各试验组长薄鳅的的摄食率差异显著(P<0.05),摄食率依次为鱼组>虾组>鱼+饲料组>虾+饲料组>饲料组;虾组和鱼组的饵料系数无显著性差异(P>0.05),但显著高于其他3组(P<0.05),其他3组间无显著性差异(P>0.05)。不同投喂模式下长薄鳅幼鱼的生长系数b值均小于3,呈负异速生长,但虾+饲料组的长薄鳅幼鱼生长系数b值最大。试验过程中各组鱼的肥满度均下降。研究结果显示,在本试验的不同饵料投喂模式中,投喂虾+饲料更利于长薄鳅的摄食和生长。     

饲料中补充蜡样芽孢杆菌(Bacillus cereus)生物膜对凡纳滨对虾(Litopenaeus vannamei)生长、抗病力及其肠道微生物组成的影响

为了研究外源补充蜡样芽孢杆菌(Bacillus cereus)生物膜对凡纳滨对虾(Litopenaeus vannamei)生长、抗病力及对其肠道微生物组成的影响,以基础饲料为空白组,在基础饲料中添加蜡样芽孢杆菌游离态活菌作为游离态组(活菌含量为108 CFU/g);在基础饲料中添加蜡样芽孢杆菌活菌生物膜作为生物膜组(活菌含量为108 CFU/g);每组8个平行.在养殖大棚暂养7d后,对凡纳滨对虾进行40 d的养殖实验.在第17天进行白斑综合征(White Spot Syndrome Virus,WSSV)攻毒实验;第22天进行副溶血弧菌(Vibrio parahaemolyticus)攻毒实验.期间在第1、5、10、15天采样,称重并测量体长计算生长速率.在第1、5、10、15、20、25天采样,并取其肠道内容物提取DNA,用16S rDNA序列V3+V4区高通量测序方法检测对虾肠道内微生物群落的结构及变化情况.结果显示,生物膜组和游离态组对虾体重、体长增长速率高于空白组,生物膜组与游离态组对虾体重、体长差异性不显著,生物膜组和游离态组对虾体重、体长与空白组相比差异性显著.实验中凡纳滨对虾肠道微生物由变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)等组成,其中,变形菌门平均占到总量的94.0％.变形菌门中主要以弧菌属(Vibrio)、发光杆菌属(Photobacterium)、Octadecabacter等为主,生物膜组、游离态组、空白对照组弧菌属平均含量分别为34.65％、39.27％、58.00％.在WSSV攻毒实验中,生物膜组、游离态组、空白对照组平均累积死亡率分别为80.0％、77.0％、92.0％,各组差异性不显著(p＞0.05).在副溶血弧菌攻毒实验中,生物膜组、游离态组、空白对照组平均累积死亡率分别为61.3％、75.0％、77.3％,生物膜组与游离态组和空白对照组相比差异性显著(P＜0.05).研究表明,饲料中添加蜡样芽孢杆菌生物膜和游离态蜡样芽孢杆菌投喂凡纳滨对虾后,可改变对虾肠道的微生物组成,提高凡纳滨对虾生长速度、增强抗病能力,而且添加蜡样芽孢杆菌生物膜效果最明显.     

Method for determining the physical stability of shrimp feeds in water

Three methods for measuring the water stability and leaching characteristics of shrimp pelleted feeds were developed and tested: static water method, horizontal shaking method and vertical shaking method. Each method was tested using a commercial and experimental pelleted shrimp feed. Both feeds had a pellet size of 2.4 mm × 5.0 mm with similar proximate composition (35% protein and 9% fat). Each test run consisted of leaching c. 2 g of feed at six intervals of immersion time (0, 30, 60, 120, 240, 360 min), two concentrations of salinity (0, 34 ppt), and three different water temperatures (15, 25, 35 °C). A refrigerated circulating water bath was used to maintain the desired level of water temperature. For the static water and horizontal shaking methods, a Buchner filtration apparatus with Whatman filter paper no. 3 (5 μ) was used to separate the remaining pellets from leached water. The vertical shaking method (VanKel) utilized a perforated stainless‐steel basket (381 μ) for leaching and serving as a filter to separate pellets from leached water. For all three methods, the leached feed and original feed samples were dried in a convection oven at 105 °C for 24 h and then cooled in a desiccator. Dried feed samples were weighed and analysed for dry matter retention. Pellet stability was calculated as the ratio of dry matter retention after leaching and dry matter of original samples expressed as a percentage. Results indicated that any method for pellet stability analysis should take into account water temperature and salinity in addition to actual pellet agitation rate to obtain accurate and consistent measurement of pellet disintegration and nutrient leaching. Dry matter retention was different for each shrimp feed with experimental feed (72.8%) showing lower retention than commercial feed (88%) after 6 h of VanKel leaching under normal shrimp culture conditions. The three methods provided reproducible results with both horizontal and vertical shaking methods recommended for routine laboratory analysis because they could provide different degrees of pellet agitation that simulate actual indoor and outdoor shrimp culture conditions.     

Survival and growth of western rock lobster Panulirus cygnus (George) fed formulated diets with and without fresh mussel supplement

Two trials were conducted to compare the growth and survival of western rock lobster Panulirus cygnus post-pueruli and year 1 juveniles fed different diets. Trial 1 compared lobsters fed a formulated pelletised feed developed for Panulirus ornatus supplemented with fresh mussels (Mytilus edulis) two days per week, with lobsters fed a daily diet of pellets. Trial 2 compared lobsters fed the pellet-mussel supplement diet with those fed a daily diet of fresh mussels.In the first trial, diet treatment did not significantly affect survival, although it was higher in tanks supplemented with mussels. Growth of post-pueruli and year 1 juveniles fed the pellet diet (0.03 g/day; 0.14 g/day, respectively) was significantly lower than growth of post-pueruli and year 1 juveniles fed pellet-mussel supplement diets (0.07 g/day; 0.2 g/day, respectively). Year 1 lobsters fed the pellet-mussel supplement diet consumed considerably less pellet (0.27 vs 0.40 g pellet dry matter/day (DM/day)) than those fed pellets indicating that they will preferentially favour mussel over pellet diets. Feed conversion ratio (FCR) was significantly better for lobsters fed the pellet-mussel supplement diet as a result of the poor growth of pellet-fed lobsters.In the second trial, survival was significantly higher for lobsters fed mussels only. Growth of post-pueruli fed a mussel diet (0.14 g/day) was significantly higher than those fed pellet-mussel diets (0.11 g/day), but there was no significant difference in growth for year 1 juveniles (0.33 g/day). Feed intake of mussel on a dry matter basis was higher than pellet intake for both size classes, with mussel intake being more than double pellet intake for post-pueruli (0.20 vs 0.49 g DM/day).Poor growth of P. cygnus on a pellet only diet indicates that the current formulation for P. ornatus may be inadequate for P. cygnus. However, as pellet intake declined dramatically for year 1 lobsters offered a mussel supplement, and pellet consumption was significantly lower than mussel consumption, it is more likely that poor growth may be attributed to inadequate palatability and intake. The similarly good survival of lobsters fed pellet and pellet-mussel diets indicates that the pellet diet is an acceptable maintenance diet for P. cygnus, but is not suitable for maximising growth for this species. Further research is needed to improve palatability, intake and potentially nutritional composition of this pellet diet before its suitability for P. cygnus is assured.     

The value of sea urchin,Lytechinus variegatus,egesta consumed by shrimp,Litopenaeus vannamei

Sea urchins produce high‐energy, membrane‐bound fecal pellets that contain residual nutrients and large quantities of microbiota. These egesta are readily consumed by the shrimp, Litopenaeus vannamei. Egesta of the sea urchin, Lytechinus variegatus, were evaluated as a feed supplement or total replacement for a commercial shrimp diet. Shrimp were stocked at 0.49 g ± 0.06 g initial body weight and housed individually in 2.8‐L tanks in a commercial recirculating zebrafish system. Shrimp were assigned to one of six diets: commercial shrimp feed, reference sea urchin feed, collected dried sea urchin egesta, collected wet sea urchin egesta, half ration of shrimp feed and half collected wet sea urchin egesta, and egesta naturally produced by two sea urchins in polyculture. Equivalent dry matter amounts of each diet were proffered to shrimp in each treatment twice daily, except for those that had complete access to natural egesta excreted by sea urchins in polyculture. Sea urchins were proffered a reference sea urchin feed at 2% body weight daily. After 27 days, shrimp proffered collected dried or wet egesta did not differ significantly in percent weight gain and showed the lowest weight gain. The percent weight gain of shrimp fed the commercial shrimp diet did not differ significantly from that of the shrimp fed half commercial shrimp diet and half egesta. The highest weight gain was recorded for those shrimp that consumed the untouched egesta produced by sea urchins in polyculture. These data suggest that consumed egesta have noteworthy nutritional value and therefore would be beneficial to the culture of extractive species in an integrated multitrophic aquaculture system.     

蚯蚓与蝇蛆对中国对虾生长及抗白斑综合征病毒感染的研究

以中国对虾（Fenneropenaeus chinensis）为实验材料，分别投喂配合饲料、蚯蚓、蛤蜊、蝇蛆等四种饵料，利用生长和抗病性指标综合评价蚯蚓和蝇蛆作为中国对虾饵料的可行性。生长实验前测定每个实验组的初始体长和体重，养殖40d后再次测定生长指标，之后，分别投喂不同毒饵量进行人工感染实验。方差分析表明：投喂四种饵料后，蛤蜊组生长最快，其次是蚯蚓，再次是蝇蛆，最后是配合饲料，各组之间对虾体长增长差异显著（P<0.05），体重增长差异极显著(P<0.01) 。利用线性固定模型分析不同饵料及不同病毒量感染下对中国对虾存活率的影响，其中蚯蚓组存活率最高，配合饲料组存活率最低，并且蚯蚓组存活率显著高于蛤蜊组和配合饲料组(P<0.05)，蝇蛆组显著高于配合饲料组（P<0.05）。研究结果表明：蚯蚓和蝇蛆可显著提高中国对虾的生长速度，明显提高中国对虾的抗病性，是很好的对虾饵料。     

不同大豆产品替代鱼粉饲养南美白对虾的试验

分别采用脱皮豆粕、大豆蛋白、发酵豆粕等大豆产品,等氮替代饲料中10%的鱼粉(对照组鱼粉35%,替代组鱼粉25%),饲养体重为0.06 g南美白对虾(Penaeus vannam eiBoone)一个月,结果表明,对照组(35%鱼粉)幼虾的增重率、成活率均最大,为1316%、97.5%;脱皮豆粕组幼虾的增重率为最低,仅783%;哈姆雷特大豆蛋白、比多福大豆蛋白、富肽蛋白(发酵豆粕)组幼虾增重率为1033%、983%、1050%,均显著高于脱皮豆粕组(P<0.05),但低于对照组(P<0.05);对虾体肌肉成分的分析显示,各组幼虾肌肉在水分、蛋白质含量方面没有显著差异。上述结果表明,大豆蛋白和发酵豆粕均为优于脱皮豆粕的鱼粉替代品。     

Lupin kernel meal as fishmeal replacement in formulated feeds for the Whiteleg Shrimp (Litopenaeus vannamei)

Rapidly expanding global aquaculture requires sustainable, local protein sources to supplement the use of fishmeal. Lupin seed meal (Lupinus angustifolius) was tested as sustainable diet component for Whiteleg shrimp (Litopenaeus vannamei). Controlled feeding experiments were conducted in a recirculating aquaculture system for eight weeks. Juvenile shrimps were provided formulated diets containing various levels of lupin meal inclusion (0, 100, 200 and 300 g kg^?1) supplementing the fishmeal component, and a commercial feed as general reference. Shrimp survival, growth, metabolic and immune parameters were analysed. Survival did not differ significantly between groups. Growth performance was significantly impaired in shrimp fed diets containing more than 100 g kg^?1 lupin meal. Lupin meal supplementation did not affect haemolymph protein content, whereas glucose and acylglyceride concentrations varied between treatments and were highest in animals fed the 100 g kg^?1 lupin meal diet. Phenoloxidase activity was highest in shrimp fed 100 g kg^?1 lupin meal diet indicating improved immune status. The present study indicates that low inclusion levels of lupin meal do not cause adverse effects and seem to stimulate the immune system of juvenile L. vannamei.     

Effects of replacing fish meal with soybean meal and peanut meal on growth,feed utilization and haemolymph indexes for juvenile white shrimp Litopenaeus vannamei,Boone

An 8‐week feeding trial was conducted to evaluate the effects of replacing fish meal (FM) with soybean meal (SBM) and peanut meal (PM) on growth, feed utilization, body composition and haemolymph indexes of juvenile white shrimp Litopenaeus vannamei, Boone. Five diets were formulated: a control diet (FM30) containing 30% fish meal and four other diets (FM20, FM15, FM10 and FM5) in which protein from fish meal was substituted by protein from SBM and PM. The dietary amino acids of diets FM20, FM15, FM10 and FM5 were equal to those of the diet FM30 by adding crystalline amino acids (lysine and methionine). Each diet was randomly assigned to triplicate groups of 30 shrimps (initial weight = 0.48 g), each three times daily. The results indicated that shrimp fed the diets FM15, FM10 and FM5 had poor growth performance and feed utilization compared with shrimp fed the control diet. No difference was observed in feed intake, survival and body composition among dietary treatments. The plasma total cholesterol level of shrimp and the digestibility of dry matter, protein and energy contained in the diets decreased significantly with increasing PM and SBM inclusion levels. Results of this study suggested that fish meal can be reduced from 300 to 200 g kg^?1 when replaced by a mixture of SBM and PM.     

Replacement of Fish Meal with Soybean Meal,Alone or in Combination with Distiller's Dried Grains with Solubles in Practical Diets for Pacific White Shrimp,Litopenaeus vannamei,Grown in a Clear‐Water Culture System

The objective of this study was to evaluate inclusion of distiller's dried grains with solubles (DDGS) as partial replacement of commercial, solvent‐extracted soybean meal (SBM) in fish meal‐free diets for Pacific white shrimp, Litopenaeus vannamei. Aquaria connected to a recirculating biofiltration system were utilized to evaluate growth, survival, and feed conversion of shrimp during the 8‐wk feeding trial. Each 110‐L aquarium was stocked with 15 shrimp (mean individual weight 0.99 g) and fed one of five diets: a diet containing 20% fish meal (FM), which served as the control (Diet 1); a diet containing 0% FM and 52.5% SBM (Diet 2); and diets containing 0% FM and either 10, 20, or 30% DDGS as partial replacement of SBM (Diets 3, 4, and 5, respectively). Shrimp were fed according to a pre‐determined feeding chart five times daily (0730, 1030, 1330, 1630, and 1930 h) and there were three replicates per dietary treatment. The results from the feeding trial demonstrated that final weight, weight gain (g), and percentage weight gain were significantly higher (P < 0.05) for shrimp fed Diet 1 (10.96 g, 10.01 g, and 1051%, respectively) compared to shrimp fed diets containing DDGS; however, shrimp fed diets containing DDGS had similar (P > 0.05) final weight, weight gain (g), and percentage weight gain as shrimp fed a diet containing 0% FM and 52.5% SBM (Diet 2). Feed conversion ratio (FCR) of shrimp fed Diet 1 (2.84) was significantly lower (P < 0.05) compared to shrimp fed any other diet. Survival (%) was not different (P > 0.05) among treatments and averaged 77.3% for the study. This study demonstrated that practical shrimp diets containing no FM had an adverse impact on growth performance of white shrimp when grown in a clear‐water system and that further research is needed to refine diet formulations when culturing shrimp in these systems when attempting to feed a diet without FM.     

Utilization of Deoxynivalenol‐Contaminated Hard Red Winter Wheat for Shrimp Feeds1

Wheat is used in shrimp feed as protein and energy sources, as well as a nutritive binder that promotes water stability. However, wheat may be contaminated with deoxynivalenol (DON or vomitoxin) when wet weather conditions prevail during the growing season. Deoxynivalenol‐contaminated wheat was added to shrimp diet to obtain DON levels of 0.2, 0.5, and 1.0 ppm. Pelleted diets were fed 3 times daily until satiation to Pacific white shrimp Liropenaeus vanna‐mei. Biological performance (live weight, weekly growth increment, feed conversion ratio, and survival) was determined biweekly for 16 wk. Histological characteristics of shrimp were determined on samples obtained after 8 and 16 wk of growth. The DON levels in ground wheat, feed mash, pellets, and freeze‐dried shrimp were determined using thin layer and high performance liquid chromatography. Deoxynivalenol levels of 0.2, 0.5, and 1.0 ppm in the diet significantly reduced shrimp body weight and/or growth rate. However, the effects of 0.2 and 0.5 ppm DON were manifested at later stages of shrimp growth, and 0.2 ppm DON significantly affected only growth rate and not body weight (P > 0.05). Feed conversion ratio and survival of shrimp fed diets containing 0.2, 0.5, and 1.0 ppm DON were not significantly different from those of shrimp fed the control diet (0.0 ppm DON). After 16 wk of growth, no DON was detected in freeze‐dried shrimp, and no consistent difference was observed in the histological organ profiles of shrimp fed diets containing various levels of DON. Because low levels of DON in the diet can significantly reduce body weight and growth rate of shrimp, feed ingredients should be monitored for DON.     

Quality evaluation of different types of non-fish meal diets for yellowtail

SUMMARY: Two feeding experiments were conducted to evaluate the feed quality of non-fish meal diets having the same protein ingredient composition but prepared as different types, and to determine the supplemental effect of crystalline essential amino acids (EAA) on feed utilization by young yellowtail, Seriola quinqueradiata . Non-fish meal diets formulated with soy protein concentrate, defatted soybean meal, corn gluten meal, meat meal, and krill meal were prepared as either soft dry pellets (SDP) or extruded pellets (EP) by using a large- or a small-sized twin screw extruder under different preparation conditions; or as a single moist pellet (SMP), each with and without EAA mixtures. Commercial yellowtail SDP was used as the control diet. Fish weighing 134 g and 237 g on average were reared with the experimental diets, for 93 (net cages) and 44 (aquariums) days, respectively. The fish fed both the control and test diets were found to have a good appetite. Growth rate and feed gain ratio were highest in the control diet group. The physiological condition of fish fed the control diet was evaluated as superior compared to those on the non-fish meal diets. Among the non-fish meal diet groups, the best performances were obtained for fish fed the SDP type diet with EAA supplement, and performance parameters excelled in the order of SDP, EP and SMP both among the diets with and without supplemental EAA. This suggests that the nutritional quality of non-fish meal diet was affected by the diet preparation method. It also indicates that supplementation of EAA could improve the quality of non-fish meal diets, irrespective of the diet type, probably as a result from the enhancement of feed protein utilization.     

Response of blue shrimp Litopenaeus stylirostris (Pérez-Farfante & Kensley, 1997) to dietary cadaverine supplementation

Recent studies on salmon and shrimp have shown that reduced feed intake and growth caused by the consumption of low‐quality fish meals, manufactured from spoiled fish, were not due to the presence of biogenic amines. Moreover, an improvement in weight gain was seen in blue shrimp fed a diet supplemented with cadaverine plus histamine. It was not clear, however, if this effect was due to the consumption of histamine or cadaverine. The objective of the current experiment was to investigate the effect of dietary cadaverine supplementation on growth parameters and various amine concentrations in tissues of the blue shrimp Litopenaeus stylirostris. Six experimental diets were supplemented with cadaverine at 0, 500, 1100, 2300, 3500 and 4600 mg kg^?1 and tested in a feeding trial lasting 28 days. Feed consumption, feed conversion ratio, survival and weight gain were not affected by the concentration of dietary cadaverine. The dietary supplementation of cadaverine, however, resulted in a linear increase in cadaverine concentration in shrimp tissues, especially in the hepatopancreas. It was concluded that dietary cadaverine does not have any effect on growth and feed intake of shrimp. Growth promotion, as reported previously in shrimp fed a diet supplemented with histamine plus cadaverine, was probably due to histamine or a combined effect of histamine plus cadaverine but not due to dietary cadaverine alone. It seems that shrimp have a limited ability to metabolize cadaverine, which then accumulates intact in shrimp tissues.     

壳聚糖硫酸酯提高凡纳滨对虾抗白斑综合征病毒感染力的研究

论述如下一项研究,采用壳聚糖硫酸酯添加到饲料中投喂凡纳滨对虾,4周后检测对虾血清酚氧化酶、超氧化物歧化酶和溶菌酶活性;同时进行白斑综合征病毒(WSSV)的肌肉注射感染实验,以检测壳聚糖硫酸酯对病毒的抗感染能力。实验结果显示,饲料中壳聚糖硫酸酯添加量为0.15‰和0.50‰,能显著提高凡纳滨对虾血清酚氧化酶活性;添加量为0.15‰时,能显著提高对虾血清超氧化物歧化酶活性,但添加量继续增大时反而下降;在低添加量时,对虾血清溶菌酶活性与对照组相近,添加量为0.15‰和0.50‰时,对虾血清溶菌酶活性随添加量增大而升高。凡纳滨对虾摄食添加壳聚糖硫酸酯饲料4周后,经注射WSSV攻毒感染,壳聚糖硫酸酯添加量为0.04‰、0.15‰和0.50‰试验组,对虾比成活率分别为39.3%、42.9%和53.6%,而未摄食壳聚糖硫酸酯的对照组成活率仅为17.9%。结果表明,摄食壳聚糖硫酸酯可以明显提高对虾抵御WSSV感染的能力。