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南美白对虾养殖中最头痛的问题白便,如何做到对虾白便的有效防控

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在南美白对虾养殖的过程中,“白便”,“空肠空胃”以及“偷死”已经成为困扰养殖户的三大难题,尤其是拉白便问题近日来越发严重。通常来说,一旦对虾出现拉白便的情况,若不及时处理,很快就会演变为空肠空胃,甚至恶化为大面积偷死,给养殖户造成巨大的经济损失。为了有效预防对虾偷死,提高养殖成功率,我们必须重视对虾白便的问题。

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南美白对虾白便发病症状

1,初期:症状不明显,对虾摄食正常,可能出现暴食的现象随着病情的发展,对虾食欲减退,可能出现拖便通过解剖发现,此阶段的病虾肝胰脏的脂肪减少,但体积变化不大。

2,中期:对虾摄食缓慢,虾身瘦弱,开始出现空肠空胃,少量虾粪呈细长白色线状,有粘性此时,对虾的肝胰腺体开始萎缩,腺管上皮脱落,肠道逐渐变白,粘膜上皮畸变脱落,肠壁细胞增生。脱落的腺管上皮,肠道黏膜上皮和增生细胞随粪便一同排出,形成“白便”。

3,后期:大量白便聚集且浮于水面并散发恶臭,对虾开始游塘,甚至偷死在这一时期,病虾的肝胰腺管严重萎缩,上皮脱落,坏死,肠壁细胞不断增生及脱落,已无法恢复。

南美白对虾白便发病原因

1,品种不良,体质欠佳

投放的虾苗品种不良,自身体质较差,肝胰脏的结构和功能不健全,或者养殖过程滥用损害肝胰脏的抗生素和刺激性较大的药物,都会直接导致对虾发病

2,细菌感染

XX通过对患病虾的解剖,发现肝脏和胰腺中的副溶血性弧菌,哈维氏弧菌,溶藻弧菌和创伤弧菌等病原体显着超标。大多数弧菌是兼性厌氧革兰氏阴性细菌,可以分布在池塘水,池塘或池塘底部,或附着在水和植物表面,体内,饲料和诱饵上。虾被感染后,弧菌可在体内迅速增殖,产生毒素,引起疾病。

3.藻毒素中毒

由气候突然变化或人类管理不当引起的水产养殖水域和藻类的富营养化可导致藻类毒素的大量积累。藻毒素主要包括红细胞毒素和蓝毒素。前者会毒害和抑制鱼虾的神经系统和呼吸系统,导致虾死亡;随着蓝藻的老化,死亡和破裂,后者会释放到水中,被虾吃掉后肝细胞就会被破坏。在胃中,它会引起肝脏,胰腺和胃肠道的损伤。

4.水质和基质变质

良好和稳定的池塘水质是南美洲虾类养殖成功的基础。随着繁殖时间的不断增加,饲料诱饵,排泄物,死藻等有机残留物的积累以及频繁使用化学消毒,絮凝剂改变底部等因素将导致水质不稳定,热量,气味,缺氧,氨氮和亚硝酸盐等有毒物质超标,导致病原体发芽甚至爆发。如果水不及时调整,虾会长时间处于恶劣环境中,肝脏和胰腺的负担会加重,胃肠功能会紊乱,很容易产生白便,而且将是黑色,腐烂,红色,破碎,白色等症状。

南美洲白虾的有效预防措施

“白便”通常被认为是“空腹”和“被盗死亡”的前兆,而“白便”是由肝脏和胰腺中的病原菌,藻毒素,水质和其他因素引起的慢性病变。因此,应采取“预防为主,预防和治疗”的手段,有效防止白便的发生。

(1) Strengthen management: Ensure that the pond is patrolled at least three times a day. When inspecting the material table, pay attention to observe the feeding, vitality and feces of the shrimp; pay attention to the weather forecast and take preventive measures against climate change.

(2) Reasonable feeding: feeding high-quality feed, the amount of feeding and the number of feedings should be reasonable.

(3) Baogan Jianchang: Add bile acid to the shrimp feed to protect the liver and pancreas while strengthening nutrition, and timely supplement minerals and vitamins.

(4) Steady water to change the bottom: Regularly disinfect the pond bottom.

Why bile acids can effectively prevent prawns from white stools

(1) The addition of bile acid can promote the digestion and absorption of fat, improve the utilization of cholesterol and polyunsaturated fatty acids in shrimp, and deoxycholic acid and ursodeoxycholic acid in bile acids can promote the secretion of a large amount of thin bile from liver cells. Other harmful substances such as mycotoxins, heavy metals and drugs are discharged from the liver and pancreas with bile, thereby reducing the damage of toxic substances to the liver and pancreas. In addition, bile acids can bind or decompose endotoxin in the intestinal tract, preventing endotoxin from entering the liver through the portal vein through the portal vein. To reduce the absorption of endotoxin in the intestine, increase the intestinal barrier, and prevent endotoxin from harming the intestine, hepatopancreas and even the entire shrimp body;

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(2) On the other hand, bile acid acts as an effective fungicide to inhibit the excessive proliferation of intestinal bacteria and maintain the intestinal micro-ecological environment: due to the surface activity of bile acids, deoxycholic acid can destroy the cell membrane of bacteria and make cells Impaired integrity, which in turn inhibits bacterial growth and even causes bacterial cell death. Exogenous supplementation of bile acid increases bile secretion, and the binding of bile acids in the intestinal cavity enhances the inhibition of bacteria in the small intestine, thereby inhibiting the excessive growth of intestinal bacteria, reducing the incidence of bacteria and endotoxemia, and effectively preventing enteritis of Penaeus vannamei. happened.

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