Studies On The Tolerance Of High Temperature Of A New Strain Haliotis Discus Hannai Ino From Qingdao

The abalone, Haliotis discus hannai Ino, is an economically important marine culture shellfish in China. In recent years, it had been becoming a main variety of abalone breeding industry in the South China Sea. However, the mortality in the high temperature season was limited by high mortality in summer. Selecting high temperature resistant variety to increase survival rate became the key project for researchers. In this study, growth experiment,immune factors detection method and fluorescent quantitative PCR technology were adopted to explore the ability of high temperature resistance of a new strain Haliotis discus hannai Ino. The high temperature resistance performance of this new strain abalone was evaluated from different aspects, which contributed to generalize the abalone in the South China Sea and investigate on anti-adversity breeding of shellfish.1 Effects of high temperature stress on growth and survival rate of juvenile Haliotis discus hannai Ino.Healthy juvenile Haliotis discus hannai Ino, averaging weight 0.23 ± 0.02 g and averaging shell length 11 ± 0.25 mm, were selected in these experiments. The abalones were divided into control group(22℃), and treatment groups(25℃, 28℃, 31℃). The experiment lasted for 45 days, and then the growth and mortality of each group were studied. The mortality of each group was 2.2%, 11.1%, 43.3% and 81.1% respectively. Growth rate of shell length of each group was 1.2%, 0.5%, 0.3% and 0.1%, growth rate of shell width of each group was 1.2%, 0.6%, 0.3% and 0.1%, growth rate of wet weight of each group was 6.6%,3.3%, 1.7%, 1.1% and 1.2%. The results indicated that when the temperature was higher than optimum temperature, the mortality of animals increased and growth rate slowed with the increasing temperature; it could be evaluated that high temperature resistance of the Qingdao Haliotis discus hannai Ino was above 30℃.2.Effects of high temperature stress on immune factors of juvenile Haliotis discus hannai InoNext, we studied the different activities of SOD, AKP, ACP and LZM between the four temperature treatment groups were studied with increasing of temperature gradually. The results indicated that when the temperature exceeded the optimum temperature range, the activity of SOD, ACP and LZM increased with the temperature increasing, while AKPdecreased slightly when the temperature increased to 31℃. The results suggested the abalone could resist high temperature damage through adjusting regulation of immune factors.3.mRNA expression of HSP70、HSP90、Fer1、Fer2 in two different Haliotis discus hannai Ino populations with acute stimulation of high temperatureThe two abalone populations(Qingdao population and Shanwei population), each of which were divided into three groups, were treated with acute stimulation of high temperature. Water temperatures of each population were shifted from natural temperature directly to preset temperatures, which were 24℃, 28℃, and 32℃, and maintained for an hour.After stimulation, abalones were sampled from each group in different times. The expressions of HSP70, HSP90 and Fer1, Fer2 were measured by fluorescence quantitative PCR technology. Expressions of those genes were increased after heat shock. HSP70, HSP90,Fer1, Fer2 expressed differently at different time in different groups. HSP90 expressed higher in Shanwei population than in Qingdao’s, the highest expression multiple was nearly 250 times. Fer2 expressed higher in Qingdao population than Shanwei’s, the highest expression was close to 3000 times. While expressions of HSP70 and Fer1 in both populations were all significantly lower than those of HSP90 and Fer2. It indicated that Fer2 and HSP90 played more important roles in high temperature resistance than HSP70 and Fer1.4.Comparison of high temperature resistance of Qingdao and Shanwei populationThe high temperature resistance of Qingdao population and Shanwei population was studied at this section, abalones were treated as content 2. Water temperature was gradually changed, morality of the two groups was separately 13.3%, 20% respectively in 24℃treatment group; it was 54.7%, 61.1% respectively in 27℃ treatment group; it was 66.7%,81.9% respectively in 30℃ treatment group. The results showed that the high temperature resistant ability of Qingdao population was higher than Shanwei population.