| White shrimp(Litopenaeus vannamei),because of its strong resistance, fast growth, long breeding time, resistant to low salinity, good taste and the advantages of easy to intensive farming, it has became one of the world’s three big shrimp breeding. But as a result of environmental deterioration of the breeding, shrimp germplasm has degraded seriously, coupled with the outbreak of various diseases in recent years, shrimp farming industry in China caused huge impact. Therefore, thorough develop marina prawn breeding, has become the marina shrimp industry of our country sustainable development the top priority. This experiment select the fifth generation of SPF shrimp breeding program as parents at University of Guam(UOG) to make 10 new generation families by artificial insemination, then compare the growth traits and expression of related genes in seawater(salinity 32) and desalting water(salinity 2), for breeding Litopenaeus vannamei families with excellent growth traits and more optimal desalting water farmed, provide a reference for the prawn breeding, the specific research results are as follows:1.This test through the construction of artificial insemination with semen transplants, and developed 10 families as subsequent experiment material. The method of artificial insemination is smear the sperm from male shrimp directly to the spermatheca of female shrimp, studied the impact of different weight of male and female to the artificial insemination rate, fertilization rate and average hatching rate, and compare with the other results of another scholars, analyses the advantages and disadvantages of this method. the results indicate: when the male and female shrimp weight over 40 g and 35 g, this method has high artificial insemination rate, when female weight less than 40 g, male shrimp less than 35 g, the artificial insemination rate and fertilization rate reaches the minimum; About the fertilization rate, the weight of female W(40-45 g),it reaches the highest, lowest when W(≤40 g), from high to low is: W(40-45 g) > W(≥50 g) > W(45 to 50 g) > W(≤40 g). About the male weight over W(40-45 g), it also reaches the highest fertilization rate, lowest when W(≤35 g), from high to low are: W(40-45g)>W(35-40g)>W(≥45g)>W(35g≤).In average hatching rate, the weight of female is W(40-45g),it reaches the lowest, W(≥50 g) hightest, from high to low: W(≥50g)>W(≤40g)>W(45-50g)>W(40-45g),from high to low of male: W(≥45g)>W(45-50g)>W(40-45g)>W(≤35g). But it still lower than the reported of the other scholars, analysis the reason may be caused by: 1.During seedling, the water temperature is too high, the water temperature more than 29 ℃ during seedling, expecially during Jun to Set, the water temperature reached 30 and 31 ℃, higher than the optimum seedling temperature. At the same time, the small volume barrels(120L), and the high water temperature, we found that the cream floating on the surface of water frequently during incubation, it lead to hatching barrels of water quality variation easily. 2. Shrimp in the breeding period, not enough nutrition. With longer on reproductive cycle, the nutrients and energy that the gonads storage can transfer to the egg in less and less, when the intake of nutrition can’t keep up with, is easily led to the decrease of the quality of the egg, makes the fertilization rate and hatching rate fault directly.2. This test using the first chapter to foster ten artificial insemination by fellow family as experimental material, and analysis growth performance of each family in the different salinity water(salinity 32 and salinity 2), the results indicate: different families shows the different performance in daily weight growth rate, family 5 highest and family 1lowest, the daily weight growth rate from high to low is: family5>family 9>family 6>family 3>family 10>family 8>family 7>family 4>family 2>family 1.family 5 and 9 showed better growth characteristic, daily weight growth rate was 21.91% and 18.43%. family 6 and 7 in low salinity of the average daily weight growth rate in low salinity is better than its value in the high salinity.Campare the surval rate of 2 different salinity, we found that low salinity groups generally lower than higher, and in the two kinds of salinity, the survival rate exist significant difference. Contrast in specific growth rate(SGR): stages in 0-44 d,both of high and low salinity’s SGR are rapid growth period, but the high salinity group SGR is higher than low salinity; After 44 d, growth rate of each family is slowing, into a period of steady growth, and low salinity group started higher than the high salinity group in SGR. Among them, family 5, 9 under two kinds of salinity, in every period of SGR is greater than the other families, its growth performance is better than the other groups in every stage.3.This test select three relative genes and 10 family’s samples from chart 2 and research the different tissue expression, and combining the growth traits, analysis the advantages and disadvantages in the future breeding, the results indicate: In low salinity group, the family 4,5,6,7,8 have higher expession of ATP synthase than the other families and express in mucles mainly, the family 1,2,3,9,10 have lower experssion. The expression of Na~+-K~+-ATPase in gill, the low salinity group higher than high salinity group, and family5,6,7,9 are lower,family1,2,3,4 are higher. About Toll-like receptor, family1,2,3,8,10 are higher, it shows that those families are strongly influenced by environmental factors, and keep in a vulnerable stage, family5,6,7,9 are lower, it shows that there is stronger ability to resist environmental change and body stability. Family 5,6 have higher expression of ATP synthase, lower expression of Na~+-K~+-ATPase and TLR, combining the growth situation, that family 5,6 can make lots of ATP, and is mainly used for the growth of the body; Family 8 Na~+-K~+-ATPase and TLR, expression is higher, also suggests that the body consumes a lot of energy in the process of osmotic adjustment and the body’s immune.In high salinity group, the level of ATP synthase expression are mainly as follows: family 4,5,6,7,8 are higher, and different with low salinity group, the mainly tissues of expression is in hepatopancreas; Each family expression quantity of Na~+-K~+-ATPase are relatively low, the body don’t need to consume large amounts of energy in the osmotic adjustment; About TLR gene expression, family4,5,6,8 are relatively lower, family 7,9,10 are relatively higher. Also don’t assign too much energy to adjust the osmotic pressure of high salinity group, family 5, 6, 7, 8 can make a large number of ATP synthesis, while the low TLR expression, family 5, 6 can use the energy mainly to the body’s growth, therefore, showed better growth performance.To sum up, family 5, 6 can distribute the energy more rational both in 2 kinds of salinity, the growth performance also better, so family 5, 6 can be used as the family with better growth performance for selective breeding. family 6, 7 show more better growth performance in low salinity than high salinity, can be used as the optional family with more suitable desalting water farmed for later breeding. |
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