微生态制剂对糙海参生长、消化酶活性及水质的影响

Effects of microecological preparation on growth and digestive enzyme activities of Holothuria scabra larvae and water quality

以受精后24 h孵化出的糙海参(Holothuria scabra)耳状幼体为研究对象,探讨养殖水体不同微生态制剂对糙海参苗期生长、存活、消化道消化酶活性和养殖水体水质变化的影响。实验设5个处理组,每隔5 d分别向4个试验组育苗池泼洒乳酸菌(浓度为1×108cfu·mL-1)15g(G1)、芽孢杆菌(总菌数为5×109·g-1)10 g(G2)、光合细菌(浓度为1×1011cfu·mL-1)50 mL(G3)和复合菌(G4,包含光合细菌30 mL、乳酸菌10 g和芽孢杆菌3 g),对照组(C)不添加微生态制剂。实验结果表明:试验组的糙海参出苗体重显著高于对照组(P<0.05),而G1的体重明显大于其余试验组(P<0.05),G3和G4之间的差异不显著(P>0.05);成活率由高到低依次为G4、G3、G2、C、G1,其中G2和C之间差异不显著(P>0.05),其余组之间差异显著(P<0.05)。微生态制剂的添加还能不同程度地影响糙海参苗体消化道的蛋白酶、淀粉酶和纤维素酶活性,G3和G4的蛋白酶和淀粉酶活性显著高于其它组(P<0.05),两组之间差异不显著(P>0.05);G1和G4的纤维素酶活性显著高于其它组(P<0.05),两组之间差异不显著(P>0.05)。各试验组苗池水质的氨氮、亚硝酸盐和COD值分别在实验第10天、20天和30天显著低于对照组,微生态制剂对糙海参苗期养殖池的总磷(TP)影响不大(P>0.05)。研究结果表明,糙海参育苗池中泼洒微生态制剂可以促进幼体的生长,提高消化酶活性和成活率,并有改善育苗水体水质的作用。

Sea cucumber Holothuria scabra （Jaeger） , or sandfish, is a widely distributed and economically important species in China. It is a commercially valuable aquaculture species, cultured extensively in tropical regions. Previous studies have been carried out on the reproduction of this species in China, viable intensive tank-based techniques for the post-nursery culture of this species have not yet been developed. Microbial ecological agent, also called probiotics, is a kind of living bacteria preparation used in aquaculture, which can degrade the ammonia nitrogen （NH4-N）, nitrite nitrogen （NO2-N） and hydrogen sulfide （H2S） and other harmful substances in aquatic water. It can also improve the intestinal microecological environment and secrete digestive enzymes to increase feed conversion rate, prevent diseases and promote growth. But there are relatively few studies on the application of probiotics in Holothuria scabra at seedling stage. This experiment studied the application of four kinds of probiotics on growth, survival, digestive enzyme activities in the digestive tract of Holothuria scabra seedlings and their influence on aquaculture water quality to improve the growth speed and raise survival rate of Holothuria scabra seedlings. Effects of microecologieal preparation on water quality and growth, survival and digestive enzymatic activities of Holothuria scabra larvae were studied using auricularia larvae hatched after 24 h fertilization. The experiment lasted for 40 days and five groups were set up and each group has three replicates. Lactobacillus 15 gram（G1,1 ×108 cfu · mL-1）, bacillus 10 gram（G2,total count 5 × 109·g-1） , photosynthetic bacteria 50 mL（ G3,1 ×10ll cfu · mL-1）and mixed microorganism（ G5, photosynthetic bacteria of 30 mL, lactobacillus 10 gram and bacillus 3 gram） were added respectively into tanks （5 m× 3 m × 1.5 m）once every five days, C was the control group and no microecological preparation was added . Each tank had 4 000 larvae. Results showed that the body weight in the test groups were significantly higher than that in the control group （P 〈 0.05 ）, while the body weight in G1 was significantly higher than that in other groups （P 〈 0.05 ）, there was no significant difference between G3 and G4 （P 〉 0.05 ）. The survival rate increased in the sequence of G1, G1, G2, G3, G4, but there was no significant difference between G2 and G1 （P 〉 0.05）, yet there were significant differences between each two groups （P 〈 0.05）. Microecological preparation can also affect the activities of protease, amylase and cellulose in the intestines of the larvae. The enzyme activity of protease and amylase in G3 and G4 were significantly higher than that in other groups （ P 〈 0.05 ）, but there was no significant difference between the two groups （ P 〉 0.05 ）. The enzyme activities of cellulose in GI and G4 were significantly higher than that in other groups （P 〈 0.05 ）, but there was no significant difference between the two groups（P 〉0.05）. The ammonia nitrogen, nitrite contents and chemical oxygen demand （COD） in test groups were significantly lower than that in the control group （P 〈 0. 05 ） at the tenth day, twentieth day and thirtieth day in the experiment respectively. The use of microecological preparation had little influence on total phosphorus （TP） during the nursing process of Holothuria scabra larvae. Results demonstrated that the microecological preparation could enhance the growth and digestive enzyme activities of Holothuria scabra larvae and improve the aquaculture water quality.