【作者】 李波；

【导师】 樊启学；

【作者基本信息】 华中农业大学 ， 水产养殖， 2010， 硕士

【摘要】 本文研究了氨氮和亚硝酸盐对不同发育阶段黄颡鱼(Pelteobagrus fulvidraco)的急性毒性效应,并初步阐明了不同溶解氧水平下氨氮和亚硝酸盐对黄颡鱼急性毒性效应的影响,并深入分析了慢性氨氮胁迫对黄颡鱼幼鱼生长、摄食的影响；同时,通过血液生化指标和能量收支代谢,分析黄颡鱼机体的应激反应和能量收支代谢途径变化规律,丰富了黄颡鱼的毒理研究资料,为黄颡鱼的健康养殖提供科学依据。首先,为了明确黄颡鱼对氨氮和亚硝酸盐的敏感性,以及敏感性是否与黄颡鱼规格存在密切联系,通过96h半静水方式水生生物急性毒性试验法,采用了4种规格的黄颡鱼(规格Ⅰ0.034±0.002 g、规格Ⅱ0.296±0.049g、规格Ⅲ3.516±0.946 g和规格Ⅳ32.958±5.748 g)进行了急性毒性试验。结果表明：4种规格黄颡鱼在氨氮和亚硝酸盐暴露96h后,其非离子氨的96h半致死浓度(96h LC50)分别为0.37 mg/L、0.54 mg/L、0.71 mg/L、1.03 mg/L；亚硝酸盐的96h LC50分别为69.03 mg/L、97.18mg/L、133.55 mg/L、195.96 mg/L。从仔鱼到成鱼阶段,黄颡鱼对非离子氨和亚硝酸盐的敏感性逐渐降低,其鱼体规格与96h LC50存在密切的相关性(P<0.05)。在高溶氧(10.77±0.40)mg/L、中等溶氧(6.89±0.33)mg/L和低溶氧(3.45±0.54)mg/L水平下,通过96h半静水方式水生生物急性毒性试验法,研究了氨氮和亚硝酸盐对黄颡鱼急性毒性效应。结果显示：高溶氧水平下,非离子氨和亚硝酸盐对黄颡鱼的96h LC50分别为0.74 mg/L、137.69 mg/L；在中等溶氧水平下,氨氮和亚硝酸盐对黄颡鱼的96h LC50分别为0.54 mg/L、97.18 mg/L；而低溶氧水平下,氨氮和亚硝酸盐对黄颡鱼的96h LC50分别为0.34 mg/L、54.22 mg/L。在3种不同溶氧水平下,非离子氨对黄颡鱼的毒性明显大于亚硝酸盐对黄颡鱼的毒性,说明氨氮对黄颡鱼的毒性成为其养殖过程中的重要影响因子；同时,高溶氧可以降低非离子氨和亚硝酸盐对黄颡鱼的毒性,因而,可以通过增加水体中溶解氧来降低非离子氨对黄颡鱼的毒性,提高黄颡鱼养殖的存活率。为了进一步探讨慢性氨氮胁迫对黄颡鱼幼鱼的生长、摄食及血液指标的影响,挑选规格相近的健康黄颡鱼分别饲养在氨氮浓度为3.36 mg/L(A1)、6.72 mg/L(A2)、13.44 mg/L(A3)、26.88 mg/L(A4)的水体中,对照组(Ao)用不加外源氨氮的自然晾晒的自来水饲养。每组放养试验鱼30尾,暴露56d。结果表明,非离子氨对黄颡鱼幼鱼的生长、摄食及血液指标存在显著影响(P<0.05),而对鱼体成分的影响不显著(P>0.05)。随着非离子氨浓度升高,高浓度组摄食率明显下降,饲料利用率降低,生长缓慢,特定生长率(SGR)和存活率都较对照组低。血氨浓度随非离子氨浓度升高而显著升高(P<0.01),各处理组血氨浓度远低于其所处环境总氨氮(TAN)浓度,而血浆尿素氮(Ur-N)水平逐渐降低但差异不显著。A3和A4碱性磷酸酶(AKP)活性和皮质醇水平升高较快,A1和A2尽管呈上升趋势但与对照组差异不显著(P>0.05)。血糖(GLU)浓度总体上表现为降低的趋势,2个高浓度组(A3和A4)下降速度较快。谷丙转氨酶(ALT)和谷草转氨酶(AST)活性总体呈升高趋势,非离子氨浓度越大其升高趋势越明显。因此,黄颡鱼幼鱼不宜长期生活在高浓度的氨氮胁迫环境中,适宜的养殖水体中氨氮应该保持在低于6.72 mg/L水平。更多还原

【Abstract】 In this paper, the toxicity of ammonia and nitrite were studied in different developmental stages of the yellow catfish (Pelteobagrus fulvidraco), and the chronic impact of ammonia levels on growth performance of juvenile yellow catfish. And we explained firstly the effects of ammonia and nitrite toxicity on yelllow catfish at high, medium, and low dissloved oxygen. Through the results of the blood biochemical parameters, stress response and energy metabolism pathway were understand in yellow catfish.The 96 h median lethal concentration (96 h LC50) tests were conducted using four different sizes of yellow catfish to provide primary information on the sensitivity of this species to elevate ammonia or nitrite, and to determine if the sensitivity is mediated by size. The results showed that the 96 h LC50 of fish weightedⅠ0.034±0.002 g,Ⅱ0.296±0.049 g,Ⅲ3.516±0.946 g and IV32.958±5.748 g to un-ionized ammonia were 0.37 mg/L,0.54 mg/L,0.71 mg/L and 1.03 mg/L, respectively, and nitrite were 69.03 mg/L, 97.18 mg/L,133.55 mg/L and 195.96 mg/L, respectively. These results indicated that the susceptibility of this fish to ammonia or nitrite reduced with increasing size, and existed in certainly correlations between them (P<0.05).Through 96 h the water aquatic acute toxicity test, the acute toxic effects of ammonia and nitrite on yellow catfish were studied at high dissloved oxygen (10.77±0.40) mg/L, medium dissloved oxygen (6.89±0.33) mg/L, and low dissloved oxygen (3.45±0.54) mg/L. The results showed that the 96 h LC50 of un-ionized ammonia and nitrite to the yellow catfish were 0.54 mg/L, and 97.18 mg/L respectively at medium dissolved oxygen level. While they were exposed to high dissolved conditions, the 96 h LC50 of un-ionized ammonia and nitrite were increased to 0.74 mg/L and 137.69 mg/L respectively. When they were exposed to low dissolved conditions, the 96 h LC50 of un-ionized ammonia and nitrite were respectively decreased to 0.34 mg/L,54.22 mg/L respectively. No matter at what dissolved oxygen conditions, ammonia was much stronger than nitrite in toxicity to yellow catfish. So ammonia in toxicity to the yellow catfish is one importent factor in duration of aquaculture. At the same time, yellow catfish tolerated much higher concentrations of nitrite or un-ionized ammonia under high dissloved oxygen. At last, the way that could improved the yellow catfish endurance to nitrite and un-ionized ammonia was also advanced in this study to increase the survival of the yellow catfish farming.The effects of sublethal ammonia were determined with respect to the stress on growth, food intake and blood parameters of the yellow catfish juveniles. The health of catfish were respectively kept in ammonia concentration (3.36 mg/L,6.72 mg/L,13.44 mg/L,26.88 mg/L, and the control group. Four hundred and fifty fish in good health and condition were evenly distributed among fifteen 280-L circular fiberglass tanks, and the exposure time was 56 d. The results showed that un-ionized ammonia had significantly effected on growth, feeding and blood parameters for the yellow catfish juveniles, but not significantly different on the body composition (P>0.05). With the increase of un-ionized ammonia, feeding rate was significantly decreased and feed efficiency reduced, which having slowly growth and higher mortality. Plasma ammonia concentration significantly increased (P<0.01), and the treatment group blood ammonia concentration was much lower than the surrounding total ammonia (TAN). However, plasma urea nitrogen levels were not difference signifficantly in all experimental groups. Alkaline phosphatase (AKP) activity and cortisol levels increased quickly in two concentration group (A3, A4), although increased in the low concentration group compared with the control group, but not significantly different (P>0.05). Glucose (GLU) concentrations generally showed a decreasing trend of two high concentration group (A3, A4) decreased rapidly. Alamine aminotransferase (ALT) and aspartate aminotransferase (AST) activity tended to increase overall, the more obvious in the high un-ionized ammonia concentration, the greater the tendency of its increase. Therefore, it was not appropriate for yellow catfish juveniles in the high concentration of ammonia, and should be maintained at less than 6.72 mg/L.更多还原