對dui蝦xia具ju有you生sheng長chang快kuai,養yang殖zhi周zhou期qi短duan,產chan量liang高gao,見jian效xiao快kuai和he經jing濟ji效xiao益yi明ming顯xian等deng優you點dian。但dan近jin年nian來lai的de病bing害hai嚴yan重zhong,而er且qie有you愈yu演yan愈yu烈lie的de趨qu勢shi,蝦xia病bing已yi成cheng為wei製zhi約yue對dui蝦xia養yang殖zhi業ye發fa展zhan的de瓶ping頸jing問wen題ti。
一、對蝦病害的主要原因 對蝦的致病因素很多,包括環境理化因素、營養因素、管理因素和生物性因素等。
1、環境因素。主要是水質。水質惡化,許多重金屬離子、youduwuzhijiyaxiaosuanyandengkezhijieweihaiduixia,shixiatibianruo。shuizhongyincanerhuoxiadefenbianguoduoyijiyoujiwuwurandengyuanyinzaochengfuyingyanghua,yifangmianshimouxiefuyoushengwudaliangwuxianzhidifanzhi,xingchengjueduiyoushizhongerchanshengshengtaipinghengshitiao,yanzhongshixingchengchichao,shishuizhijinyibuehua。lingyifangmianzeyinshengwuzhijiandezhiyuezuoyongjianruo,jiashangyoudaliangyingyangwuzhicunzai,cujinleyouhaiweishengwudedaliangfanzhi,yinergezhongjibinghuixiangjifasheng。lingwai,huanjingyinsudegaibianyekezhijieyinqiduixiahuanbing。
2、營養因素。對蝦為了維持生命活動、自身的生長和繁殖,必須從人工飼料或天然餌料中攝取所需的營養物質。這些營養物質包,括蛋白質、脂類、碳水化合物、無機元素、維生素等。這些營養素的缺乏會導致相應的缺乏症,降低蝦體的抵抗力,使對蝦容易患病。
3、管(guan)理(li)因(yin)素(su)。在(zai)對(dui)蝦(xia)的(de)人(ren)工(gong)養(yang)殖(zhi)中(zhong),由(you)於(yu)放(fang)養(yang)密(mi)度(du)過(guo)高(gao),除(chu)容(rong)易(yi)導(dao)致(zhi)水(shui)質(zhi)變(bian)壞(huai)外(wai),對(dui)蝦(xia)互(hu)相(xiang)接(jie)觸(chu)的(de)機(ji)會(hui)較(jiao)多(duo),有(you)利(li)於(yu)病(bing)原(yuan)體(ti)的(de)傳(chuan)播(bo),而(er)且(qie)蝦(xia)體(ti)之(zhi)間(jian)互(hu)相(xiang)幹(gan)擾(rao)較(jiao)大(da),可(ke)引(yin)起(qi)其(qi)生(sheng)理(li)機(ji)能(neng)失(shi)調(tiao),抵(di)抗(kang)力(li)下(xia)降(jiang)而(er)發(fa)病(bing)。此(ci)外(wai),投(tou)餌(er)過(guo)多(duo)可(ke)引(yin)起(qi)水(shui)質(zhi)的(de)汙(wu)染(ran)和(he)造(zao)成(cheng)水(shui)體(ti)的(de)富(fu)營(ying)養(yang)化(hua)。
4、生物性因素。生物性致病因子又稱為病原體。主要的有病毒(杆狀病毒、節對蝦杆狀病毒、腸腺壞死杆狀病毒、胰腺細小樣病毒、蝦呼腸孤病毒、頭杆狀病毒、蝦白斑綜合症病毒、染性皮下及造血組織壞死病毒、巴器官細小樣病毒、蝦桃拉綜合症病毒)、細菌 (弧菌、杆菌)、真菌、寄生蟲等。
二、防治對策 疾病的發生與否取決於蝦體、環境以及病原體之間的關係。蝦體主要是指蝦的抗病力;環境主要是水環境;病原體則為各種生物性致病因子。針對上述的致病因素,病害的防治對策如下:
1、治理工業廢水和城市生活汙水.隨sui著zhe沿yan海hai經jing濟ji的de發fa展zhan,大da量liang的de工gong業ye廢fei水shui和he城cheng市shi生sheng活huo汙wu水shui不bu經jing處chu理li即ji排pai人ren近jin海hai水shui域yu,導dao致zhi近jin岸an水shui域yu的de水shui質zhi惡e化hua,直zhi接jie威wei脅xie著zhe對dui蝦xia養yang殖zhi業ye的de生sheng存cun和he發fa展zhan。因yin此ci,必bi須xu對dui工gong業ye廢fei水shui和he城cheng市shi生sheng活huo汙wu水shui進jin行xing治zhi理li,做zuo到dao無wu害hai化hua排pai放fang。
2、科學投餌;baozhengsiliaozhiliang。xuduoduixiayangzhichangshiyongderengongerliaozhiliangcha,zaishuizhongdewendingxingdabudaoyaoqiu,jiazhicaiqubujinhelidetouercelve,jieguoshixiangdangshuliangdeerliaotouweihoubunengbeiduixialiyong,fanerwuranshuizhi。tichangduoyongyingyangquanmian,shuizhongwendingxinghaodepeihesiliao,buyongmeibianheguolebaozhiqidepeihesiliao。tousiyaojianchidingdian、定時、定質、定量和少量多次的方法,投飼量一定要計算準確,並要根據實際情況合理調整,寧少勿多。
3、采用適宜的養殖模式,改善養殖環境。目前我國對蝦養殖模式有:①chuantongdechitangnachaoyangzhimoshi。danchitanggouzaodaduobijiaojianlou,shuiweiyejiaodi,yangzhipinzhongdanyi,miduguoda,yichaochanashuihepaishui,buyiqingtang,yizaochengchitanglaohuaheshuizhijiaochawuran,rongyidaozhixiabingdebaofa。②蝦與魚、貝、蟹(xie)混(hun)養(yang)養(yang)殖(zhi)模(mo)式(shi),可(ke)充(chong)分(fen)利(li)用(yong)水(shui)體(ti),有(you)利(li)於(yu)清(qing)除(chu)殘(can)餌(er)和(he)病(bing)蝦(xia),可(ke)起(qi)到(dao)改(gai)善(shan)水(shui)質(zhi)和(he)減(jian)少(shao)病(bing)原(yuan)體(ti)傳(chuan)播(bo)的(de)作(zuo)用(yong),但(dan)必(bi)須(xu)注(zhu)意(yi)交(jiao)叉(cha)感(gan)染(ran)的(de)問(wen)題(ti),選(xuan)擇(ze)合(he)適(shi)的(de)混(hun)養(yang)種(zhong)類(lei)很(hen)重(zhong)要(yao)。③海hai水shui淡dan化hua養yang殖zhi模mo式shi和he鹵lu淡dan水shui養yang殖zhi模mo式shi,主zhu要yao應ying用yong於yu斑ban節jie對dui蝦xia和he南nan美mei白bai對dui蝦xia的de養yang殖zhi,也ye是shi目mu前qian南nan美mei白bai對dui蝦xia的de主zhu要yao養yang殖zhi模mo式shi。高gao位wei池chi精jing養yang模mo式shi具ju有you排pai水shui清qing淤yu徹che底di、曬底容易、底di質zhi保bao持chi良liang好hao等deng優you點dian,可ke減jian少shao病bing害hai的de發fa生sheng,是shi較jiao理li想xiang的de養yang殖zhi模mo式shi,但dan此ci種zhong養yang殖zhi模mo式shi投tou入ru較jiao大da。因yin此ci,要yao因yin地di製zhi宜yi,選xuan擇ze合he適shi的de養yang殖zhi模mo式shi。
4、消滅或控製病原體,阻斷傳播途徑。包括徹底清淤消毒,改善蝦池底質;選用無特異病原(SPF)蝦苗;合理的放苗密度;病蝦的及時處理及嚴格檢疫等。 蝦池經過幾年的養殖會出現不同程度的老化,每年以5cm~10cm左zuo右you的de速su度du增zeng厚hou,池chi底di成cheng了le細xi菌jun和he病bing毒du等deng病bing原yuan體ti的de繁fan殖zhi地di。因yin此ci,徹che底di清qing淤yu消xiao毒du是shi預yu防fang蝦xia病bing十shi分fen重zhong要yao的de基ji礎chu工gong作zuo。要yao盡jin量liang將jiang各ge種zhong有you機ji物wu和he汙wu泥ni從cong池chi中zhong搬ban走zou,清qing除chu表biao層ceng15cm~25cm。也可利用塑料薄膜覆蓋塘底隔離病原體。
5、tigaoduixiadekangbingli。gaozhiliangdexiamiaoheyouliangdeyangzhihuanjingshitigaoduixiakangbinglidegenbenbaozheng。yaochuangzaolianghaodepeimiaohuanjinglaipeiyugaozhiliangdexiamiao。zaipeihesiliaozhongjiaruweishengsuC和多糖類等一些免疫增強劑可在一定程度上提高養殖對蝦的抗病力。
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