yes, usually the very first batch of eggs is noit very fertile so does noit hatch very well. Most people discard and use the second batch
unless you use old males, which can provide better fertility
EMS = Early Mortality Syndrome
Early mortality syndrome can be caused by a number of different pathogenic, environmental and management issues. Some, but not all of this appears to be caused by a new and previously unknown syndrome called Acute Hepatopancreatic Necrosis Syndrome (AHPNS)
In Vietnam sampling has shown only 50% of EMS is caused by AHPNS (the rest is WSSV and other problems)
In Thailand – the figures are <30% caused by AHPNS
could you be specific so i can answer?
Cause unknown for 4 years, but this month, Dr. Lightner from Arizona, working with Flegal in Mahidol and FAO/ NACA/World Bank finally identified causative agent as a specific strain of Vibrio parahaemolyticus transmitted orally & colonizing intestine作者: 水寶寶 時(shí)間: 2013-6-18 16:10
in general, lower PH means less probelm with vibrio(vibrio is the cause of EMS), and also, high PH can cause probelm with Amonia which stress the shrimp. so keep in low PH is good idea.
我贊成。維持較低的PH值可減著少弧菌的煩擾（弧菌現(xiàn)在被認(rèn)為是導(dǎo)致EMS的原因），同事，過(guò)高的PH還會(huì)帶來(lái)氨氮對(duì)蝦造成應(yīng)激的問(wèn)題。因而，降低PH值是個(gè)不錯(cuò)的措施。作者: 逆游的魚(yú) 時(shí)間: 2013-6-18 16:24
之前羅馬的聯(lián)合國(guó)糧農(nóng)組織發(fā)布報(bào)告稱(chēng)，副溶血弧菌是造成近年來(lái)部分亞洲國(guó)家蝦大量死亡、減產(chǎn)的“兇手”。真的是這樣的嗎?作者: 夏天的雨 時(shí)間: 2013-6-18 16:24
對(duì)于馬修在海南會(huì)上講到，在養(yǎng)殖過(guò)程中，要做好清塘工作，是每一口塘都要這么做嗎？
在中國(guó)，有人養(yǎng)蝦一整年都不換水，他們認(rèn)為蝦塘的水質(zhì)已經(jīng)處于穩(wěn)定狀態(tài)了，如果排掉后再培水，是非常的浪費(fèi)和徒勞！因?yàn)樗w到達(dá)藻相平衡、菌相平衡需要較長(zhǎng)的時(shí)間，一般放苗前都沒(méi)有等那么久的，也就是說(shuō)放苗的時(shí)候，藻相、菌相都沒(méi)有真正穩(wěn)定。作者: 和蟹天然 時(shí)間: 2013-6-18 16:24
Hello! Dr. Matthew：
Shrimp larvae breeding beneficial bacteria commonly used are those ? How about the ratio between species ? think you!
馬修博士，您好！請(qǐng)問(wèn)在蝦苗育苗當(dāng)中常用的微生物有益菌有那些種類(lèi)？種類(lèi)之間大概的比例怎樣？ 作者: 逆游的魚(yú) 時(shí)間: 2013-6-18 16:25
代網(wǎng)友提問(wèn)：
高溫天氣的水質(zhì)地質(zhì)管控與肝臟萎縮腸炎白便偷死的預(yù)防以及治療方法是什么？
normally we use probiotics which are mostly comprised of a mixture of bacillus and lactobacillus species - these can help remove toxic ammonia and nitrite, outcompete vibrios and actually kill off bad vibrio species. They thus improve environmental conditions.
some people also brew their own non-pathogenic vibrio strains in the hatchery, but they do not help water quality, only outcompete pathogenic vibrios
yes, organic acids can lower pH in fish/shrimp gut from pH 7 to pH 4-5 which can kill pathogenic gram negative bacteria like vibrios, buit does not kill gram positive probiotic bacteria
this is used alot in livestock (pig, chicken) but not much yet in shrimp. But it does work both in hatchery and pond farms
in Chinese hatcheries the main problem is reliance on old ways of management. There does not seem to be much capacity for problem solving.
I think the biggest problem is not using live algae. Live algae must be grown with care so it is not contaminated and then is ideal feed for larvae, but also helps maintain water quality and even reduce vibrios. If it is done badly and poor quality then it is bad, so most Chinese hatcheries do not do it. If done properly it is very good.
the other main problem is a focus on quantity rather than quality. In order to get high quality PL you must focus on quality
如果能提供真是非常感謝! 郵箱:463790331@qq.com。作者: 逆游的魚(yú) 時(shí)間: 2013-6-18 16:42
對(duì)于EMS早期的補(bǔ)救都有哪些措施了？作者: 馬修 時(shí)間: 2013-6-18 16:44
Normally, we only use the broodstock for 4 months as after that they become used up and do not produce good quality nauplius any more. So once we ablate, we use continuously for 4 months, then get a new batch. We do not stop and start with the same batch作者: 和蟹天然 時(shí)間: 2013-6-18 16:47
馬修 發(fā)表于 2013-6-18 16:34
yes, organic acids can lower pH in fish/shrimp gut from pH 7 to pH 4-5 which can kill pathogenic gra ...
翻譯：是的，有機(jī)酸能將蝦腸道內(nèi)的PH從 7降至4-5，可以殺死致病性革蘭氏陰性菌如弧菌，但不殺死革蘭氏陽(yáng)性菌。目前很多家畜（豬，雞）上都在這樣使用，蝦上用的不多。但它的確在苗場(chǎng)養(yǎng)殖和養(yǎng)殖場(chǎng)都非常有效。作者: 馬修 時(shí)間: 2013-6-18 16:50
If you have already got EMS you must stop feeding immediately for 5-7 days then start again slowly after that. You stop feeding to try to improve the environment and help the shrimp recover. also, controlling water quality (with probiotics) and trying to keep algae bloom stable and not allow rapid fluctuations in pH or high pH levels may help. However, sometimes none of this helps and you mjust harvest pond and start again
You are right - the hatchery is controlled and "sterile" environment while the pond fluctuates widely
Normally the PL or even juveniles in the nursery do not suffer from EMS, but when we stock the ponds, immediately they do. Thus the stress of moving them and the stress factors in the ponds obviously affect them very quickly.
Many Asian farmers are used to killing everything in the pond to try to start clean, but if you do that (with chlorine or pesticide) then quickly bacteria will grow back - there is always bacteria - you cannot stop them. so you have to make sure the ones that grow back are non-pathogenic - i.e. add alot of probiotics or heterotrophic bacteria right away during pond preparation otherwise bad bacteria will grow quickly.
One farm in Thailand avoids EMS by not killinbg everything, but fertilizing to produce good bloom of diatoms and zooplankton (copepods) to promote a good environment at it seems to work to avoid EMS
木醋液可以防EMS？
剛剛看到一個(gè)網(wǎng)友的發(fā)帖 作者: 馬修 時(shí)間: 2013-6-18 17:02
Shrimp and fish polyculture is very good, as the right species of fish has a very positive effect on the water quality (especially vibrio levels) in the water and sediment, helping the shrimp to fight disease. Many times, the culture is still mostly shrimp (stocked at 50-60/m2) and the fish is just there for improving environment (0.5 fish/m2). Normally herbivorous fish are used which do not east the shrimp - like tilapia or mullet or milkfish. Of course, this means lower stocking density, so less profit, but more sustainable - so long term it is a better strategy and works to prevent diseases like EMS and WSSV and IMNV作者: 淡泊寧?kù)o 時(shí)間: 2013-6-18 17:10
雖養(yǎng)魚(yú)不養(yǎng)蝦，也來(lái)頂一下外國(guó)朋友作者: 和蟹天然 時(shí)間: 2013-6-18 17:15
馬修 發(fā)表于 2013-6-18 16:56
You are right - the hatchery is controlled and "sterile" environment while the pond fluctuates widel ...
Normally we would use 30-31oC for all of larval rearing cycle, but if you suffer from zoea-2 syndrome it is a good idea to increase temperature to 32, 33 or 34oC throughout zoea stage until become Mysis 1 then reduce back down to 30-31oC. This is done to push the zoea through to mysis as soon as possible at high temperature to avoid Zoea-2 syndrome. But you must maintain either 32, 33 or 34 constant day and night (do not allow temperature to fluctuate between day and night)
馬修 發(fā)表于 2013-6-18 16:44
Normally, we only use the broodstock for 4 months as after that they become used up and do not produ ...
通常，親蝦我們只使用4個(gè)月。因?yàn)槟且院螅鼈兊姆敝迟|(zhì)量就不好了。也就是剪眼后，我們連續(xù)使用4個(gè)月，然后換一批。我們不會(huì)停一段時(shí)間，然后繼續(xù)使用同一批親蝦。作者: 馬修 時(shí)間: 2013-6-18 17:22
We think white faeces syndrome is probably bacterial cause, togehter withpoor water and soil quality. So improve the environment by water exchange, siphoning wastes and using probiotics in feed (5-10g/kg of feed until gone). Other people use organic acids at 2-5 g/kg in the diet and some have success using fresh garlic at 10 g/kg crushed up and top-dressed on diet 3-5 diets per day for 2-3 days作者: 和蟹天然 時(shí)間: 2013-6-18 17:31
馬修 發(fā)表于 2013-6-18 17:02
Shrimp and fish polyculture is very good, as the right species of fish has a very positive effect on ...
We think white faeces syndrome is probably bacterial cause, togehter withpoor water and soil quality. So improve the environment by water exchange, siphoning wastes and using probiotics in feed (5-10g/kg of feed until gone). Other people use organic acids at 2-5 g/kg in the diet and some have success using fresh garlic at 10 g/kg crushed up and top-dressed on diet 3-5 diets per day for 2-3 days
