投饵时间对对虾生长的影响

在对虾营养方面,主要考虑因素之一是干颗粒饵料投入水中后的营养流失。众所周知,对虾摄食蛋白质含量高的饵料生长良好,但饵料成本太高,限制了对虾养殖的发展。因此,要努力改进价格较贵的标准饵料的用法。该研究共有5个试验.研究延迟投饵时间对于对虾生长和存活率的影响。材料与方法     

对虾配合饵料的新蛋白源——白地霉

作者以白地霉为主要蛋白源配制配合饵料投喂墨吉对虾。初步试验结果表明,墨吉对虾摄食该种饵料,胃肠饱满率高,排便频繁,而且生长正常。其饵料效果比花生饼为主要蛋白源的配合饵料的效果要好。同时经观察、分析     

提高对虾饵料利用率的几点看法

饵料是对虾赖以生活和生长的物质基础,在水质等环境因子适宜于对虾生长的条件下,最大限度地满足对虾的摄食需要,就有利于对虾的生长,提高对虾的规格和产量。目前,养成的对虾规格相差很大,且饵料利用率也不一样,如何合理投饵,降低饵料成本,本文讨论以下几个问题:     

科技动态

最近,山东省科委组织有关专家对文登市水产养殖公司承担的国家星火计划——”对虾配合饵料加工技术开发”项目进行了验收。该公司采用1987年在全国饵料投喂比赛中夺魁的饵料配方及已通过部级鉴定的BP—2型粘合剂生产的配合饵料,在水中浸泡6小时不散开,24小时后呈海绵状,便于     

鱼塘秋季管理莫放松

投饵 9月仍是鱼类摄食生长旺季，在主养吃食性鱼类的池塘，应先投喂青料，待其基本吃光，再投喂科学配制的饲料，日投两次，投饵量占鱼体重的3％～6％。10月后，日投饵1次，投饵量占鱼体重的1％～3％，投饵可持续到11月中旬。     

鱼虾加工下脚料的利用

鱼虾加工后的下脚料,除了可以直接配制饵料外,还可制成液化蛋白,作为动物蛋白源之一,配制对虾饵料。由鱼虾加工下脚料制成的液化蛋白所含必需氨基酸种类齐全,动物摄食后可直接吸收,营养价值较高。用作动物饲料喂养效果显著。现将鱼虾下脚料及其配合饵料的加工途径介绍如下:     

简法检测南美白对虾的投饵量

<正> 南美白对虾(以下简称对虾),具有摄食量大,生长快的特点,广大养殖户在精养过程中采取一日投喂三四次的方法给对虾提供饵料。但是,如何正确确定每次投饵量是一些养殖户比较难以掌握的。投多了造成饵料浪费,增加养殖成本,如不及时清除残饵,残饵腐烂造成池水变坏反而影响对虾生长;投少了对虾吃不饱造成同批次对虾规格悬殊影响产量和养殖效益。现在我们介绍一种简便检测对虾投饵量的方法供大家参考。     

对虾配合饵料的粘合剂比较试验

中国对虾南移养殖和越冬孵化在我省首获成功之后,在目前用全人工繁殖方式可以获得一定数量虾苗的情况下,提高养殖单产,降低养殖成本,成了发展我省养虾事业的当务之急,这中间饵料起着决定性作用,它是发展养虾生产的物质基础。以往,养殖对虾几乎全靠采捕天然饵料,因而常常受到海况条件、资源量和劳力的限制,不能充分满足对虾生长的需要。饵料来源不足已经严重地影响到生产的发展。进行养虾人工配合饵料的研究对于广开饵料来源、提高养殖产量、充分发挥各种单一饵料的效能、实行科学养虾具有重要意义。一九七七年,我们继续开展了对虾配合饵料的研究工作。本文仅就粘合剂的比较试验作     

浅谈渔用药物安全使用的一些技术问题(五)

由于减少了投饵量,每天的投饵次数也是必须要考虑的。对虹鳟进行每天1次投喂饱食量或者分为3次投喂后,对供试鱼摄食状况的检查结果表明,每天投喂1次饵料的试验鱼能全群平均摄食。因此,以治疗疾病为目的投喂药饵时,因为投饵量比平时减少,以     

对虾对食物中维生素B_1、维生素B_6和氯化胆碱的需要量

<正> 日本鹿儿岛县水产试验场的弟子丸修和黑木克宣对日本对虾Penaeus japonicus通过精制饵料的试验,对食物中维生素B_1、维生素B_6和氯化胆碱的需要量进行了研究。结果摘要如下: 1.饵料中维生素B_1的含量,在12周的投饵试验期间,对于对虾成长和生存的影响表现的不太明显,虽然在十周后,投喂维生素B_1缺乏的饵料组中,对虾的成长稍有缓慢。在食物中维生素B_1盐酸盐的需要量根据对虾成长的要求,经测定是每100克食物中含6毫克,在投饵试验结束时,依据对虾体内维生素B_1的含量测定是每100克食物中含12毫克。 2.在对虾早期发育阶段,投喂缺乏维生素B_6的饵料,会出现阻碍生长和死亡率高的     

Effect of glycine betaine, a feed attractant affecting growth and feed conversion of juvenile freshwater prawn Macrobrachium rosenbergii

A feeding experiment was conducted to determine the effect of the feeding attractant, glycine betaine (betaine hydrochloride) on the growth and feed conversion of juveniles of Macrobrachium rosenbergii (deMan) (mean initial weight 1.12 g). Three types of diets were prepared with the incorporation of glycine betaine at 5, 10 and 15 g kg^?1 levels along with an unsupplemented control. After 60 days, weight gain, feed intake and food conversion ratio (FCR) were higher in prawn fed the three glycine betaine‐added diets compared with the control feed. Among the glycine betaine‐added diets, prawn fed glycine betaine at 5 g kg^?1 level showed highest weight gain (2.73 g) by registering 61.5% increase in growth over control and also higher feed intake (5.79 g) and good FCR (2.12). There were highly significant differences (P < 0.01) in weight gain, feed intake, per day growth and FCR among treatments. There was no significant difference (P > 0.05) in survival among treatments.     

泼洒糖蜜对池塘养殖罗氏沼虾生长和水质的影响

将单口面积1.33~2.33hm~2、环境相似的6口罗氏沼虾养殖池塘分为2组,3口池塘投喂蛋白质水平为35.4%的饲料,且每日适量泼洒糖蜜(试验组),3口池塘投喂蛋白质水平为41.9%的饲料,不泼洒糖蜜(对照组),常规管理。养殖期间,每隔15d取水样检测氨氮和亚硝态氮含量。156d的饲养结果表明,对照组和试验组罗氏沼虾的产量分别为6600kg/hm~2和6427.5kg/hm~2,降低饲料中的蛋白水平结合泼洒糖蜜不影响罗氏沼虾的生长(P0.05),养殖效益亦无显著差异(P0.05)。但试验组池塘水中氨氮较对照组低54.0%,亚硝态氮低21.0%,泼洒糖蜜显著降低了池塘氨氮和亚硝态氮含量(P0.05)。     

Effect of dietary cellulose level on specific dynamic action and ammonia excretion of the prawn Macrobrachium rosenbergii (De Man 1879)

The feeding energetics of the prawn Macrobrachium rosenbergii (De Man 1879) were examined with respect to the effect of dietary fibre. Adult animals were fed semi‐purified diets with 0%, 5%, 10% and 15%α‐cellulose to determine the maximum aerobic scope that could be elicited by the increase in metabolism as specific dynamic action (SDA). The excretion rates of ammonia were also measured. Prawns fed all diets had significantly higher respiration rates after feeding due to SDA. Feed intake was not related to metabolism rate. Both oxygen uptake and ammonia excretion were affected by feed intake, dietary cellulose and time after feeding. SDA was related to dietary fibre, indicated by increments varying from 37% to 386%. O:N ratios were influenced by feed intake, dietary cellulose levels and time after feeding. O:N ratios of between 10 and 49 indicate that the prawns predominately metabolize carbohydrate.     

Concentration and Composition of Astaxanthin in Black Tiger Prawn Penaeus monodon Postlarvae Fed Artemia sp. Nauplii or Mauxia Shrimsp Acetes intermedius

Minced Taiwan mauxia shrimp Acetes intermedius , an alternative to brine shrimp Artemia sp. nauplii, has long been used as a principal or supplemental feed in prawn hatcheries in Southeast Asia and India. In this study, black tiger prawn Penaeus monodon postlarvae were fed with frozen brine shrimp nauplii (diet B) or minced Taiwan mauxia shrimp (diet M) for 4 wk to compare their astaxanthin concentration and composition, survival, and growth. Diet B contained two and a half times more total carotenoid (TC) than diet M, with canthaxanthin as a major (79%) carotenoid, but without astaxanthin, a predominant carotenoid in crustaceans. Of its TC in diet M, 55% was β-carotene and 17% astaxanthin. B-prawn (postlarvae fed with diet B) had a similar growth rate as M-prawn and twice the survival rate as M-prawn. The concentrations of total astaxanthin (TA), free astaxanthin (FA), astaxanthin monoester (MA), and astaxanthin di-ester (DA) in B-prawn were all higher than those in M-prawn. Except for FA, no reduction of TA, MA, or DA concentration during the feeding interval was found in B-prawn. However, concentrations of TA, FA, MA, and DA in M-prawn all decreased. TC content of the experimental diets had a greater influence on resulting prawn astaxanthin concentration and composition than carotenoid compositions of the diets.     

Nutrient efficacy of microalgae as aquafeed additives for the adult black tiger prawn,Penaeus monodon

This study used a small amount of several lyophilized microalgae (5% of dry weight in aquafeed) to feed adult black tiger prawns Penaeus monodon for 4 weeks, aiming to promote prawn health and nutritional level. Apart from slight increases in ash content, chlorophyll and β‐carotene in the microalgae‐added feeds, there was no difference from the commercial diet in their biochemical composition. After 28 days of feeding, prawn body length, body weight, condition index and also total amount of fatty acids and amino acids of the flesh (2nd abdominal segment) were not affected by microalgae additives as compared with the control commercial diet‐fed group (P > 0.05). Prawns fed the microalgae diets, however, had a relatively better survival rate than those fed the commercial control diet, although no statistical significance was detected in any except for the diatom Melosira sp. The elevated survival rate was concomitant with a higher phagocytosis rate and superoxide dismutase (SOD) activity in the immune response analysis, and significantly a higher astaxanthin content detected in the tail muscle of microalgae diet‐fed prawns (5.36–10.78 ng of astaxanthin per gram of muscle DW). These findings demonstrated that low‐inclusion microalgal additives in prawn diets over a short feeding period (4 weeks) can result in healthier adult prawn, and hence could contribute to the development of an optimized feeding strategy for prawn aquaculture close to harvesting.     

Restricted and Satiate Feeding of Two Genetically Isolated Strains of Juvenile Channel Catfish Ictalurus punctatus Reared on 28% and 32% Protein Diets

A 10-wk growth comparison trial of two strains of channel catfish Ictalurus punctatus was conducted in 40 120-L flow-through aquaria using a 2 ± 2 × 2 factorial experiment design. The three factors evaluated were: strain (Norris and NWAC103), dietary protein level (28% and 32%), and feeding rate (restricted and satiate). Average initial weight (× SD) for the Norris strain was 3.0 ± 0.08 g/fish, while that of the NWAC103 strain was 4.7 ± 0.13 g/fish. The feeding rate for the satiated group was adjusted based on feeding observations. The feeding rate for the restricted group was adjusted to about ²/₃ of the satiate level. For both satiate and restricted feeding regimens, the NWAC103 strain consumed more feed than the Norris strain. Fish of Norris strain fed the 32% protein diet consumed more feed than fish fed the 28% protein diet; however, there were no differences in feed consumption in the NWAC103 fish fed the two protein diets. Regardless of feeding rate, the NWAC103 fish gained more weight and converted feed more efficiently than the Norris fish. Fillet composition was not affected by fish strain. Fish fed the 28% protein diet had a lower level of fillet protein than fish fed the 32% protein diet. In fish fed to satiation, a 32% protein diet resulted in a lower fillet fat level than a 28% protein diet, but no differences were observed in fillet fat levels between fish fed the two dietary protein levels for the restricted group. Results from the present study demonstrate that under laboratory conditions, the NWAC103 strain of channel catfish is superior to Norris strain in feed consumption, growth rate, and feed efficiency. Our data also indicate that either a 28% or 32% protein diet can be fed to either strain of channel catfish whether they are fed to satiation or fed a restricted ration with no detrimental effects on growth.     

Yield characteristics of prawns, Macrobrachium rosenbergii (de Man), with fish polycultures at low feeding rates

Abstract. As currently practiced, freshwater prawn, Macrobrachium rosenbergii (de Man), aquaculture in Hawaii requires large inputs of supplementary feed, water and labour. The high cost of these inputs greatly restricts profit potential. An experiment was conducted to compare an alternative prawn production system which used lower feeding rates and fish polycultures to reduce inputs. Three treatments were run in quadruplicate: (1) control—prawns stocked at standard densities (11.5 per n2) in monoculture and fed standard prawn pellets at the commercial ration recommendations by New & Singholka (1982); (2) low feed—prawns at standard densities and fish [silver carp, Hypophthalmichthys molitrix (Valenciennes), grass carp, Ctenopharyngodon idella (Valenciennes), and grey mullet, Mugil cephalus (L.)] fed one-half commercial ration; and (3) maintenance feed—prawns at standard densities and fish fed one-tenth commercial ration. Although prawn yield characteristics (mean weights, harvestable sizes, survival, net yields) were not significantly different (P > 0.05) based on an analysis of variance in the three treatments over the approximately 9.5-month culture period, this lack of significance most likely resulted from interpond variability and the lack of a large number of replicates. The relatively poor survival (60–63%) of gray mullet and an almost twofold difference in prawn yields in the control and maintenance feed treatments suggest that there was in fact competition for resources in the nominally polyculture systems. Nevertheless, the wet weight yield of biomass from all species was twice as high in the low feed ponds as in the control ponds.     

Effect of dietary water on growth of dentex <Emphasis Type="Italic">Dentex dentex</Emphasis>

ABSTRACT:   This study is concerned with the effect of hyrdated diets on growth and feed performance of Dentex dentex . Three levels of dietary water were tested: 7%, 20% and 40%. For the 7% level a commercial feed was used and the 20% and 40% water levels were obtained after adding an appropriate amount of deionized water to the commercial feed and mixing the pellets well. The diets were offered to fish by self-feeders, by which fish were allowed continuous access to diets after activating the self-feeders; by belt feeders, by which the diets were fed continuously and in excess over a 12 h interval; and by hand to apparent satiation two times a day. After 151 days of feeding, the group fed on the 20%-water diet showed significantly ( P  < 0.05) higher growth rate than the 7 and 40% groups, while no significant differences were observed in feed conversion rate or daily feed consumption. The means of feed delivery did not influence growth rate. Self-feeder, belt and hand feeding all gave comparable growth. Fish fed the more condensed 7%-water diet had smaller stomachs than fish fed the larger volume 40%-water diet. In the stomach, all groups of fish hydrated their digesta within 2 h after feeding to a moisture content of around 60%. Apparently no difference in digestive process was observed between groups. It was concluded that the addition of water in diet at the level of 20% has a beneficial effect on dentex growth.     

A Comparison of Two Feeding Technologies in Freshwater Prawns,Macrobrachium rosenbergii,Raised at High Biomass Densities in Temperate Ponds

ABSTRACT

Recent developments in prawn production technologies (i.e., added substrate, increased stocking densities, size grading, and increased feed rates) have increased production rates from 900-1,000 kg/ha to over 2,500 kg/ha. While prawn can receive substantial nutritional benefit from natural foods at the lower biomass densities, at higher production rates prawn are likely to be more dependent on prepared diets. To ensure that maximum production is being achieved by these new production technologies, production rates must not be nutritionally constrained. This study was conducted to compare the current recommended technology of phase feeding of different quality feedstuffs to prawns of different sizes with the feeding of a high-quality penaeid diet throughout the production season. Two treatments were evaluated: Treatment 1 was phase feeding (current technology-control) where prawns were fed unpelleted distillers' grains with solubles (DDGS) for the first four weeks, then a 28%-protein prawn diet for weeks 5-12, and finally a 40%-protein penaeid diet for weeks 13-16. In Treatment 2, prawn were fed the 40%-protein penaeid diet throughout the entire production period. Feeding rates in both treatments were based upon a feeding table. Three 0.04 ha ponds were used for each treatment. All ponds were stocked at 59,280 juveniles/ha and were provided with artificial substrate in the form of a polyethylene “safety fence” oriented vertically to increase available surface area by 50%. After 106 culture days, no significant differences (P >0.05) were observed between treatments in terms of yield, average individual weight, food conversion ratio (FCR), or survival, which averaged 2,575 kg/ha, 46 g, 2.3, and 94%, respectively, overall. Due to the higher cost of the penaeid diet (US$0.84/kg), feeding costs for the penaeid diet treatment (Treatment 2) were 38% higher than those for Treatment 1. No benefit to using higher protein diets during the first 12 weeks of prawn pond production was observed.     

Growth enhancement and protective potential of feed-based outer membrane proteins against vibriosis in <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis>

The use of antibiotics to curtail vibriosis, which is a major infectious disease, plaguing shrimp and prawn is rather becoming less effective and the need for a better alternative is expedient. The outer membrane proteins (OMPs) of V. alginolyticus were extracted, mixed with powdered commercial feed and fed to the prawns to evaluate its effect on growth performance and protective potential. Sixty prawns were divided into groups A, B and C of 10 prawns each, with two replicates in six (150 L) glass aquaria. Groups A, B and C were fed with OMPs mixed diet, with OMPs-Freund’s incomplete adjuvant mixed diet and OMPs or adjuvant free diet (control diet) respectively. All the prawns were weighed weekly, and haemolymph was collected to determine the total haemocyte count (THC) and phenoloxidase (PO) activity. At the end of the feeding trial, prawns were intramuscularly challenged with 50 μL of 10⁷ CFU V. alginolyticus. The treated groups were significantly higher in growth performance and THC than the control group, but no significant difference between the groups in terms of PO activity and mortality rate. The study, however, submitted that oral administration of OMPs with or without adjuvant is a good growth promoter and has the potential for protection against vibriosis in giant freshwater prawn (Macrobrachium rosenbergii).