在水温26～30℃,盐度18～22条件下,初始体质量(0.012±0.000)g的拟穴青蟹仔蟹饲养在底铺1～2 cm细沙、边缘放5 cm2瓦片的塑料水桶(直径20 cm,水深20 cm)中,投喂以葡萄糖、蔗糖、糊精、木薯淀粉、玉米淀粉、糊化木薯淀粉和糊化玉米淀粉为糖源的7种等氮等能饲料,养殖3周,研究不同糖源对拟穴青蟹仔蟹生长、体组成及消化酶活性的影响.试验结果显示,不同糖源显著影响拟穴青蟹仔蟹的生长性能(P<0.05);质量增加率和特定生长率依次为糊化木薯淀粉>糊化玉米淀粉>木薯淀粉>玉米淀粉>糊精>蔗糖>葡萄糖;葡萄糖试验组的成活率显著低于其他各组(P<0.05).不同糖源对拟穴青蟹仔蟹体组成中粗蛋白和粗脂肪含量影响显著(P<0.05),对仔蟹的水分和灰分含量影响不显著(P>0.05);不同糖源对3种消化酶活性影响显著(P<0.05).拟穴青蟹仔蟹对大分子糖源的生物利用度要大于小分子糖源.在本试验的研究条件下,7种常见糖源中糊化木薯淀粉是拟穴青蟹仔蟹的最适糖源.

为探讨饲料中添加不同含量枯草芽孢杆菌对拟穴青蟹(Scylla paramamosain)幼蟹生长、消化酶活性及体成分的影响,以初始体质量为(25.74±0.51) mg的拟穴青蟹Ⅰ期仔蟹为试验对象,在基础饲料中分别添加0、0.1％和0.5％的枯草芽孢杆菌制成3种试验饲料,饲喂幼蟹3周.试验结果:添加枯草芽孢杆菌的组,拟穴青蟹幼蟹的终末平均体质量、体质量增长率、特定生长率和蛋白酶活性显著高于对照组(P＜0.05),但两个不同添加量试验组间的差异不显著(P＞0.05);添加枯草芽孢杆菌显著增强了幼蟹蛋白酶和淀粉酶的活性(P＜0.05),对幼蟹的水分、粗蛋白和灰分含量均没有显著影响(P＞0.05);添加0.5％枯草芽孢杆菌的试验组,幼蟹的脂肪含量显著高于其它试验组(P＜0.05).结果表明,在本试验条件下,饲料中添加枯草芽孢杆菌对拟穴青蟹幼蟹的生长有显著促进作用,对蛋白酶活性、淀粉酶活性和体粗脂肪含量也有显著影响,添加0.1％ ～0.5％的枯草芽孢杆菌对拟穴青蟹幼蟹有较好的促生长效果.

本试验旨在研究饲料糖脂比对拟穴青蟹仔蟹生长性能、体组成和消化酶活性的影响。以初始体重为(41.40.3) mg的拟穴青蟹仔蟹为试验对象，分别投喂糖脂比为0.54、0.88、1.39、2.08和3.50的等氮（约44%）等能（约19.5 MJ/kg）饲料3周。结果表明：1）饲料糖脂比对拟穴青蟹仔蟹的终末平均体重(FABW)、成活率（SR）、增重率（WGR）以及特定生长率（SGR）均有显著影响(P<0.05)。随着饲料糖脂比的增大，拟穴青蟹仔蟹的FABW、SR、WGR以及SGR均呈先升高后降低的趋势，且均是糖脂比1.39试验组最高，显著高于糖脂比0.54和3.50试验组(P<0.05)。2）饲料糖脂比对拟穴青蟹仔蟹的水分、粗蛋白质和粗灰分含量没有显著影响(P>0.05)，而对粗脂肪含量的影响显著(P<0.05)，糖脂比0.54试验组的脂肪含量最高，显著高于除糖脂比2.08和3.50试验组(P<0.05)。3）饲料糖脂比对拟穴青蟹仔蟹的淀粉酶活性没有显著影响(P>0.05)，但显著影响蛋白酶和脂肪酶活性(P<0.05)。随着饲料糖脂比的增大，蛋白酶活性呈先增大后减小的趋势，脂肪酶活性呈降低的趋势，糖脂比1.39试验组的蛋白酶活性显著高于其他试验组(P<0.05)，糖脂比0.54和0.88试验组的脂肪酶活性显著高于糖脂比2.08和3.50试验组(P<0.05)。由此可见，以增长率为评价指标，经回归分析得出拟穴青蟹仔蟹饲料的适宜糖脂比为2.07。

The green mud crabScylla paramamosainhas been widely cultured in coastal areas of southern China for many years, with production reaching approximately 14.1 tons in 2015. The successful farming of mud crabs presently depends on conventional diets, comprising mainly trash fish, mollusk meat and animal viscera, but the demand for these foods by the crab industry is difficult to satisfy. Compared with the traditional feeds, compound feeds offer better-balanced nutrition and have better storage qualities. Studies of the nutritional requirements of cultured mud crab are important to developing cost-effective, environmentally friendly and nutritionally balanced artificial diets. Dietary protein, a major macronutrient in aquatic animal diets, provides the essential and non-essential amino acids needed to synthesize body protein and energy. As protein represents the most expensive component in feeds, it is important to determine the optimal level for a cultured species. This study investigated the effects of dietary protein level on growth performance, body composition, and digestive enzyme activities in mud crab(S. paramamosain) juveniles. Six isoenergetic diets were formulated with varying protein content (i.e., 31.45%, 36.37%, 41.55%, 46.13%, 51.72% and 56.86%) and fed to juvenile mud crabs for three weeks. Triplicate groups of 80 juvenile crabs, with an average body weight of 11.86 ± 0.11 mg, were randomly assigned to each of the six diets. Each crab was raised in a bucket (20 cm diameter × 25 cm height) provided with a 5 cm layer of sand. The results showed that the dietary protein level did not influence crab survival rate in any of the treatments (P<0.05). The weight gain ratio and specific growth rate of the juvenile crabs significantly increased as dietary protein was increased from 31.45% to 51.72% (P<0.05), and then the indicators showed a slight decrease with a further increase to 56.86% protein; the gains were highest for crabs fed 51.72% protein. Dietary protein level sig-nificantly affected the whole-body crude protein, lipid and ash contents (P<0.05), but did not show any significant influence on the moisture content of the crabs (P>0.05). Values for crude protein content of crabs raised on one of the four higher protein diets (41.55%?56.86%) were significantly higher than that for crabs fed a lower protein diet (31.45% and 36.37%) (P<0.05), while the whole-body lipid content significantly decreased as the dietary protein content was increased (P<0.05). The trend in whole-body ash content was similar to that observed for weight gain ratio, which significantly increased at first and then decreased as the dietary protein content was in-creased (P<0.05). With an increasing level of dietary protein, the protease activity significantly increased (P<0.05) and amylase activity significantly decreased (P<0.05). The level of dietary protein also affected lipase activity in the crabs. Under the present experimental conditions, juvenile green mud crabs fed 41.55%?56.86% protein exhibited the best growth performance, and regression analysis showed that the optimal level was 49.03% protein. These results will be helpful for formulating pelleted diets for commercial mud crab culture. Future studies of protein metabolism mechanisms and the interactions of proteins with other nutritional components are recom-mended for this species.

A 3-week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid (CHO ∶L) ratio on growth performance,body composition and digestive enzyme activities of juvenile Scylla paramamosain.Five iso-nitrogenous (about 44％) and iso-energetic (about 19.5 MJ/kg) diets with varying CHO ∶L ratios of 0.54,0.88,1.39,2.08 and 3.50 were fed to juvenile Scylla paramamosain with an average body weight of (41.4±0.3) mg of triplicate groups.The results showed as follows:1) dietary CHO ∶L ratio significant affected the final average body weight,survival rate,weight gain rate and specific growth rate of juvenile Scylla paramamosain (P＜0.05),and the final average body weight,survival rate,weight gain rate and specific growth rate of juvenile crabs were increased firstly and then decreased with dietary CHO ∶L ratio increased,those of CHO ∶L ratio at 1.39 group was the highest,which significantly higher than those of CHO ∶L ratios at 0.54 and 3.50 groups (P＜0.05).2) Dietary CHO ∶L ratio had no significant influences on moisture,crude protein and crude ash contents of juvenile Scylla paramamosain (P＞0.05),but significantly affected the crude lipid content (P＜0.05).The crude lipid content of CHO ∶L ratio at 0.54 group was the highest,which significantly higher than that of CHO ∶L ratios at 2.08 and 3.50 groups (P＜0.05).3) Dietary CHO ∶L ratio had no significant influence on the amylase activity of juvenile Scylla paramamosain (P＞0.05),but significantly affected the protease and lipase activities (P＜0.05).The protease activity was increased firstly and then decreased with dietary CHO ∶L ratio increasing,while the lipases activity was decreased with dietary CHO ∶L ratio increased.The protease activity of CHO ∶L ratio at 1.39 group was significantly higher than that of other groups (P＜0.05),the lipases activity of CHO ∶L ratios at 0.54 and 0.88 groups was significantly higher than that of CHO ∶L ratios at 2.08 and 3.50 groups (P＜0.05).In conclusion,the regression model analysis show that the suitable dietary CHO ∶L ratio to reach the highest weight growth rate of juvenile Scylla paramamosain is 2.07.

Juvenile Scylla paramamosain with the average body weight of (0.042±0.002) g were fed seven isonitrogenous and isoenergetic experimental diets with different lipid levels for 3 weeks to investigate the effects of dietary lipid level on growth performance,body composition and digestive enzyme activities of juvenile Scylla paramamosain.Using fish oil and soybean oil (1:1) as the lipid source,the lipid level in the seven experimental diets was 1.93％,3.95％,6.35％,8.14％,10.54％,12.30％ and 14.22％ (measured values),respectively.Each experimental diet had three replicates and each replicate had 100 juvenile Scylla paramamosain.The results showed as follows:l) dietary lipid level significantly affected the weight growth ratio (WGR) and specific growth ratio (SGR) of juvenile Scylla paramamosain (P＜0.05).With the increase of dietary lipid level,the WGR and SGR of juvenile Scylla paramamosain were firstly increased and then decreased,and when the dietary lipid level was 8.14％,both WGR and SGR produced the maximum value.The quadratic curvilinear regression analysis showed the best dietary lipid level was 7.52％ which could acquire the best WGR.The survival rate (SR) in the group with 14.22％ dietary lipid level was the lowest,which was significantly lower than that in other groups (P＜0.05).2) Dietary lipid level had significant effects on body crude protein and ether extract contents in whole crab (P＜0.05).The crude protein content in whole crab was firstly increased and then decreased,and when the dietary lipid level was 8.14％,it produced the maximum value.The ether extract contents in whole crab with the increase of dietary lipid level continued to increase,when dietary lipid level was 14.22％,it produced the maximum value.Dietary lipid level had no significant effects on the contents of moisture and ash in whole crab (P＞0.05).3) With the increase of dietary lipid level,the activities of protease,lipase and amylase of juvenile Scylla paramamosain were firstly increased and then decreased,and all of them produced the maximum value when the juvenile Scylla paramamosain fed with diet contained 8.14％ lipid.In conclusion,taking WGR as the evaluation index,the suitable dietary lipid level for juvenile Scylla paramamosain should be 7.52％.

采用FIASCO（Fast Isolation by AFLP sequences containing repeats）技术和磁珠富集方法开发拟穴青蟹微卫星位点。结果表明,400bp以下长度的序列含微卫星的概率超过400bp以上长度的序列;从二碱基重复类型到五碱基重复类型,完美型微卫星的概率在增加。利用设计的28对引物扩增一个供试群体,其中12对引物能稳定扩增且片段大小基本符合理论长度,10个微卫星位点表现出高度多态性,9个微卫星位点显著偏离Hardy-Weinberg平衡（P＜0.05）,两组两两位点间存在连锁不平衡现象（P＜0.0042,经Bonferroni法校正）。Micro-checker分析揭示其中的5个微卫星位点可能存在无效等位基因。排除混合微卫星位点的引物对以及扩增位点PIc值在0.5以下的引物对,8对引物能用于拟穴青蟹群体遗传学等研究。