【作者】 仇登高；

【导师】 刘鹰；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生态学， 2014， 博士

【摘要】 光照是工业化循环水养殖系统中影响大西洋鲑生长及性腺发育的重要环境因子，全面了解光环境因子与大西洋鲑之间的相互作用，对于大西洋鲑的生产实践具有重要的指导意义。本论文结合养殖工程学、生理生态学、超声诊断学和半导体照明等学科，构建了大西洋鲑早期性别和发育阶段鉴别技术方法，查明了工业化循环水养殖生产系统中大西洋鲑生长性能及性腺发育的变化规律，系统地研究了光环境因子对循环水养殖系统大西洋鲑生长及性腺发育的影响效应。主要研究结论如下：（1）采用超声成像技术，探讨了大西洋鲑早期性别及发育期鉴别方法研究。研究结果表明：利用超声成像技术鉴别雌鱼的准确率较雄鱼高，其中鉴定雌鱼的准确率为93%，鉴定雄鱼的准确率为81%。根据大西洋鲑性腺发育的状况，每尾鱼超声波检测的时间约为35s。大西洋鲑Ⅲ期卵巢的超声波图像呈小三角形，结构紧密；Ⅳ、Ⅴ期卵巢的超声波图像呈白色亮点的圆形颗粒结构。而Ⅳ、Ⅴ期精巢的超声波图像则呈不规则黑影，但Ⅱ、Ⅲ期精巢的超声波图像无明显的判别特征，这两个时期的精巢需要排除Ⅱ、Ⅲ、Ⅳ、Ⅴ期卵巢及Ⅳ、Ⅴ期精巢来确定。超声成像技术鉴别Ⅲ期、Ⅳ期卵巢的准确率分别为87%、92%，对Ⅴ期卵巢鉴别的准确率达到100%。超声波技术鉴定Ⅱ期精巢的准确率仅为64%，对Ⅲ期、Ⅳ期精巢鉴别的准确率分别为71%、86%，精巢发育至Ⅴ期时的准确率为84%。超声波技术鉴定早期性腺（Ⅱ～Ⅲ期）发育的准确率较低，为75%；对晚期性腺（Ⅳ～Ⅴ期）发育鉴定的准确率较高，为89%。（2）在大西洋鲑工业化循环水养殖生产系统中，连续12个月，跟踪监测了初始体重分别为160.85±41.48g、418.00±92.29g两批降海大西洋鲑（smolts）生长及性腺发育规律。监测结果表明：2011年9月和2012年1月降海的雌、雄大西洋鲑体重和体长生长速度差异均不显著，但雄鱼生长速度整体上大于雌鱼；上述两批次的雌、雄鱼体质量体长拟合函数关系式W=aLb中b值均大于3.0，显示工业化循环水养殖生产系统中雌、雄大西洋鲑体重生长大于体长生长。雌、雄大西洋鲑各生长阶段的体质量特定生长率、相对增重、肥满度、体质量变异系数及生长激素的变化趋势基本一致，即各生长指标呈现变化幅度不同的波浪式规律。在循环水养殖生产系统中，雌性大西洋鲑卵巢启动时间是在降海后的第9-10个月，卵巢发育较快个体的体重范围为596～2755g；雄性大西洋鲑精巢启动时间是在降海后的第6-9个月，精巢发育较快个体的体重范围为274～2880g。两批次雌、雄大西洋鲑雌二醇激素（E2）浓度水平随时间的变化均呈现先降低后升高再降低的趋势，且雌、雄鱼E2含量均无显著差异(p>0.05)。2011年9月、2012年1月降海的大西洋鲑分别在降海后第13、第8个月前睾酮(T)浓度水平变化趋势大体一致；2011年9月降海的大西洋鲑雌、雄鱼T含量均出现先升高后降低的趋势，2012年1月降海的雌、雄个体的T含量均呈现不规则的“W”式变化；上述两批次雄鱼T含量分别在第14、10个月达到最高值（即3.27、1.43ng.ml-1），且此时两批次雄鱼T水平均显著高于雌性鱼（p<0.05）。（3）以初始体重为（850.97±82.77）g的大西洋鲑为研究对象，运用正交实验方法，持续7个月，探讨了不同光谱成分（550nm，A1；455，A2；625，A3）、光周期（LD24:0，B1；LD12:12，B2；LD8:16，B3）和光强（0.88W.m-2，C1；4.55W.m-2，C2；8.60W.m-2，C3）对工业化循环水养殖系统大西洋鲑生长及性腺发育的影响。研究结果表明：在工业化循环水养殖系统中，光谱成分、光周期和光强对大西洋鲑生长、摄食影响不明显，625nm、LD12:12、8.60W.m-2是本实验条件下较为适宜的光照条件。雄、雌大西洋鲑分别在550nm、LD24:0、4.55W.m-2及550nm、LD24:0、0.88W.m-2的条件下性腺发育最快。大西洋鲑在性腺发育过程中，光周期是光环境参数中的重要因子。光周期对大西洋鲑性腺指数、睾酮激素、夜间血浆褪黑激素及雌性大西洋鲑雌二醇激素具有显著或极显著影响；光周期对雄性大西洋鲑雌二醇激素的影响不显著，光谱成分、光强对大西洋鲑性腺指数、夜间褪黑激素及睾酮和雌二醇激素均无显著的影响。（4）选取初始体重为（1071.70±155.54）g的大西洋鲑600尾，随机分为6组：24L-8L组的初始光周期LD24:0、每日缩短5min，8L-24L组的初始光周期LD8:24、每日增加5min，24L:0D组为光周期LD24:0，18L:6D组为光周期LD18:6，12L:12D组为光周期LD12:12，8L:16D组为光周期LD8:16，每组2个重复，每个重复50尾鱼，研究了不同光周期水平对循环水养殖系统大西洋鲑生长及性腺发育的影响，实验周期7个月。研究表明，实验结束时不同光周期水平对大西洋鲑成活率、体质量变异系数、肥满度、体质量特定生长率、体长特定生长率、相对增重和日增重的影响差异不显著（p>0.05）。各光周期组大西洋鲑摄食率、饲料转化效率和饲料系数的变化范围分别为0.40～0.51%/d、78.09～89.28%和1.12～1.28，光周期12L:12D组饲料系数较低，摄食率和饲料转化效率较高。各实验组白天大西洋鲑血浆褪黑激素含量无显著性差异（p>0.05），24L:0D组夜间鱼的血浆褪黑激素含量均显著低于夜间其他各实验组（p<0.05），各组由低到高依次为：24L:0D <8L-24L <24L-8L<12L:12D <18L:6D <8L:16D。8L:16D组和12L:12D组可延缓雌、雄大西洋鲑性腺发育，而24L:0D组、8L-24L组和24L-8L组均可不同程度地加快雌、雄鱼的性腺发育。上述研究成果可以为人工光照调控工业化循环水养殖大西洋鲑性腺发育提供理论依据，并将促进大西洋鲑工业化循环水养殖产业的健康发展。更多还原

【Abstract】 Lighting is an important environmental factor for affecting the growth and gonadaldevlopment of Atlantic salmon (Salmo salar) in recirculating aquaculture systems(RAS). Acomprehensive understanding of the interactions between light environmentfactors and Atlantic salmon would be instructive and meaningful to the productionpractice of Atlantic salmon. Based on the combination of these disciplines includingaquacultural engineering, physiological ecology, ultrasound diagnostics andsemiconductor lighting, the present study constructed the identification methods ofearly sex and the different stages of gonadal developoment in farmed Atlantic salmon.It also aimed to find out the changes of growth performance and gonadal developmentof the salmon in commercial RAS and systematically study the effects of lightenvironment factors on the growth performance and gonadal development in RAS.Main research results of the present study are as follows:(1) The idenfication method of early sex and gonadal development stages ofcultured Atlantic salmon were determined by using ultrasound imaging technique.The results showed that there was higher accuracy of sex identification in the femalesusing ultrasound imaging technology than that of the males, and the accuracy of theidentification in females and males was93%,81%respectively. According to sexgonadal status of Atlantic salmon, the duration time of each fish was35s. Theultrasonic images of the ovaries at stage Ⅲ appeared the characteristics of small triangles in female Atlantic salmon, and the ovarian images at stages Ⅳ andⅤ withthe structure of both the white spot and rounded particle. The ultrasound images of thetestis at stages Ⅳ andⅤwere the characteristics of the irregular shadows, while thetesticular ultrasonic images at stages Ⅱa ndⅢ were not distinguished in male fish.That is to say, the identification of the testis at stages Ⅱand Ⅲ need to exclude thestages Ⅱ, Ⅲ, Ⅳ and Ⅴ ofthe ovaries and the stages Ⅳ and Ⅴ ofthe testis. Inaddition, the accuracy of the ovaries at stages Ⅲ and Ⅳ in female fish was87%and92%respectively, and the ovarian accuracy at stage Ⅴ of was100%; The accuracy ofthe testis at stages Ⅱ, Ⅲ, Ⅳ andⅤ were64%,71%,86%and84%separately. So tospeak, the accuracy of gonadal development in early stages (namely Ⅱand Ⅲ) was(75%) lower than that of the later stages (namely Ⅳand Ⅴ), which was89%.(2) The experiment was conducted for12months to monthly monitor the changesof growth performance and gonadal development of Atlantic salmon in two batches(with initial weight of160.85±41.48g,418.00±92.29g respectively) in commercialRAS. The results indicated that there were no differences of the body weight and bodylength of male and female smolts entering seawater in September2011and January2012respectively (p>0.05). However, the growth of the males was greater than that ofthe females during the experimental period. The b values were more than3.0for theformula of the relationship between body weight and body length with W=aLbin maleand female fishes, suggesting that the growths of body weight in males and femaleswere greater than the growths of body length in commercial RAS. The changes of thespecific growth rate, relative weight gain, condition factor, coefficient of sizevariation and growth hormone level were concident and regular in various wavytendency at different growth stages. The initiation time of ovary development ofsmolts was at the nineth to tenth month into the seawater, and the body weight of theindividual which rapidly grew in ovaries ranged from596g to2755g. The initiationtime of testicular development in the salmon was at the sixth to nineth month after theseawater, and the weight of the individual which rapidly grew in testis ranged from274g to2880g. The changes of the estradiol (E2) levels in females and males were allfirstly decreased, then increased and decreased again in two batches entering seawater in September2011and January2012respectively. There were no significant effectson the E2concentrations of the female and male in two batches (p>0.05). The trend oftestosterone (T) levels of the salmon in two batches (entering seawater in September2011and January2012separately) remained the same into the seawater before thethirteenth and eighth month respectively. The T levels of female and male salmonentering seawater in September2011were all firstly raised and then reduced into theseawater after the thirteenth month, and the female and male fish entering seawater inJanuary2012showed the irregular alterations of “W” pattern into the seawater afterthe eighth month. The T concentrations of the male fish in the above two batchesreached the peak values (3.27and1.43ng.ml-1respectively) into the seawater at thefourteenth and tenth month separately, and the T levels of the males in two batcheswere both significantly higher than that of the females at this point (p<0.05).(3) The effects of spectral composition (namely, A1,550nm; A2,455nm; A3,625nm), photoperiod (namely, B1, LD24:0; B2, LD12:12; B3, LD8:16) and lightintensity (namely, C1,0.88W.m-2; C2,4.55W.m-2; C3,8.60W.m-2) on the growthperformance and gonadal development of Atlantic salmon (with initial weight of850.97±82.77g) for210days in RAS were studied by orthogonal test methods. Theresults indicated that spectral composition, photoperiod and light intensity would notaffect the growth performance and feeding of Atlantic salmon (Salmo salar) in RAS,and625nm, LD12:12and8.60W.m-2were thought to be a suitable combination ofartificial lighting under the present experimental condition. The best combinations forthe three factors with the optimum levels in male and female fish were550nm,LD24:0,4.55w.m-2and550nm, LD24:0,0.88w.m-2separately, which could induce thegonadal development of Atlantic salmon. Photoperiod was the main factor in lightenvironment parameters in the process of the gonadal development of the salmon.Photoperiod had extremely significant effects on the nocturnal plasma melatoninrelease, female E2, and male GSI and T of Atlantic salmon (p<0.01), and displayed aremarkable influences on the GSI and plasma T of female fish (p<0.05). whilephotoperiod had no such significant effect on the male plasma E2, and spectralcomposition and light intensity showed no significant effects on GSI, nocturnal plasma melatonin secretion and plasma T and E2ofAtlantic salmon (p>0.05).(4) Aseven months trail was conducted to investigate the effects of photoperiodlevels on the growth performance and gonadal development ofAtlantic salmon(Salmo salar) in recirculating aquaculture systems (RAS). Six hundredAtlanticsalmon with the initial body weight (1071.70±155.54) g were randomly distributedin six groups with two replicates per group and50fish per replicate. In the six groups,group24L-8L was initially treated under the photoperiod of LD24:0followed thereduction of5min every day, group8L-24L was initially treated under thephotoperiod of LD8:16followed the increasion of5min every day, and group24L:0Dreceiving the photoperiod of LD24:0, group18L:6D receiving the photoperiod of LD18:6, group12L:12D receiving the photoperiod of LD12:12, group8L:16D receivingthe photoperiod of LD8:16. The results displayed as follows: there were nosignificant influences of different photoperiod levels on the survival rate, coefficientof size variation, and condition factor, specific growth rate of body weight and bodylength, and relative weight gain and daily weight gain at the termination of the trial(p>0.05). The feeding ratio (FR), feed conversion efficiency (FCE) and feedconversion ratio (FCR) in all experimental groups ranged from0.40～0.51%/d,78.09～89.28%and1.12～1.28respectively. The FCR ofAtlantic salmon was lowerand the FR and FCE were higher under the photoperiod of LD12:12. There were nosignificant differences in plasma melatonin levels ofAtlantic salmon among allgroups during the daytime (p>0.05), while the plasma melatonin level ofAtlanticsalmon was lower under the photoperiod of LD24:0than any other photoperiodtreatments during the nighttime (p<0.05) and the sequence of nocturnal plasmamelatonin among all the six groups was group24L:0D <group8L-24L <group24L-8L <group12L:12D <group18L:6D <group8L:16D. The gonadaldevelopment ofAtlantic salmon (Salmo salar) was found to be delayed under thegroups of8L:16D and12L:12D and speeded up in these goups of24L:0D,8L-24Land24L-8L in recirculating aquaculture systems (RAS).The findings mentioned above in the present study will provide the theory referencefor the growth performance and gonadal development of Atlantic salmon (Salmo salar) with artificial light, and will also promote the sustainable and healthy development forthe farming industry ofAtlantic salmon in RAS.更多还原