中国科学院海洋研究所机构知识库

仿刺参，又称刺参，是我国重要海洋经济物种。繁殖期是动物重要的生活史阶段，在繁殖期动物会出现一系列特殊的行为学与生理学模式以保障配子或胚胎发育，这种亲代依靠牺牲自我而保障繁殖的现象为生殖代价。本研究以刺参生殖代价为切入点，采用生物能量分析技术、行为定量分析法与超高效液相色谱与质谱联用技术等，系统分析了刺参在繁殖阶段的能量代价、行为代价、代谢生理代价与消化生理代价特征。主要研究结果与内容如下：

1. 刺参繁殖期能量代价与适应机制研究

研究刺参在不同繁殖阶段的摄食特征与能量利用模式。结果表明，随着性腺发育，刺参摄食量、摄食率和表观消化率分别由4.49 g ind^-1 day^-1、0.4 g g^-1 day^-1和14.73%下降至2.6 g ind^-1 day^-1、0.13 g g^-1 day^-1和10.92%，即繁殖会抑制刺参食物获取能力。刺参繁殖期各阶段能量收支情况整体呈动态变化，能量摄入逐渐降低，用于性腺发育比例逐渐由1.76%增加至15.61%，而用于躯体生长能逐渐由17.1 %下降至5.64%，表明刺参通过调节体内能量分配以适应性腺发育所需的高能量需求。

2. 刺参繁殖期行为代价与适应机制研究

研究刺参在不同繁殖阶段的昼夜总运动距离、昼夜总运动时间、昼夜总运动频率、最大速度变化以及肌肉代谢生理。结果表明，随着性腺发育，刺参总运动距离和总运动时间由32.04 m和12 h逐渐下降为15.82 m和6.46 h，而运动频率无变化，且最大运动速度呈现上升趋势，即繁殖会抑制刺参运动耐力。采用超高效液相色谱与质谱联用技术，共筛选出10种非繁殖期与繁殖期刺参肌肉代谢差异物质，其中，9种代谢物在繁殖期出现明显上升，主要为溶血卵磷脂和左旋肉毒碱等，而溶血乙醇胺出现明显下降，表明刺参在繁殖期的运动行为变化主要由氧化应激与脂质代谢所调控，而行为可塑性是适应繁殖期肌肉组织能量不足的重要生活史策略。

3. 刺参繁殖期代谢生理代价与适应机制研究

研究刺参在不同繁殖阶段的的耗氧率、呼吸频率和呼吸树代谢生理。结果表明，随着性腺发育，刺参耗氧率和呼吸频率由11.84 μg g^-1 h^-1和6.22次/min增加至23.34μg g^-1 h^-1和10.15次/min，即繁殖会造成刺参基础代谢率增大，而刺参通过调节呼吸频率以适应高代谢需求。呼吸树中ATP含量在繁殖期下降，而Na⁺/K⁺-ATP酶活力显著上升。采用超高效液相色谱与质谱联用技术，筛选出23种非繁殖期与繁殖期代谢差异物质，去氧皮质酮等13种代谢物水平在繁殖期上升；而二十碳三烯酸等10种代谢物水平显著下降，表明刺参为维持繁殖期高呼吸频率需消耗大量能量，通过提高Na⁺/K⁺-ATP酶活力以加速ATP分解水平，呼吸行为的变化由氧化应激所调控，而行为与生理的协同模式是适应繁殖期高氧气需求的生活史策略。

4. 刺参繁殖期消化生理代价与适应机制研究

研究刺参在不同繁殖阶段的有机质消化率、消化酶活力和肠道代谢生理。结果表明，随着性腺发育，刺参粪便中碳氮有机质含量由1.66%和0.39%增加至2.68%和0.48%，即繁殖会抑制刺参对有机质的消化能力。刺参肠道组织中淀粉酶与胰蛋白酶活力在繁殖期由2.96 U mg^-1 protein^-1和119.45 U mg^-1 protein^-1降低至1.41 U mg^-1 protein^-1和42.78 U mg^-1 protein^-1；采用超高效液相色谱与质谱联用技术，共筛选出31种非繁殖期与繁殖期肠道组织代谢差异物质。其中，5-羟色胺与溶血卵磷脂等8种物质含量在性腺生长期与成熟期都出现上升；而尿苷磷酸等4种物质含量在性腺生长期与成熟期都出现下降，表明刺参繁殖期消化酶活力的下降主要由肠道退化与氧化损伤所导致的，而摄食选择性可能是适应繁殖期肠道退化的生活史策略。

The sea cucumber Apostichopus japonicus is the most economically important and valuable species in China. Reproduction is a key stage of animal life history. Reproduction can present behavioural and physiological challenges for animals, and causes negative fitness consequence. The negative consequences are referred to as the cost of reproduction. In this study, using bioenergetic analysis technology, behavioural analysis software and ultra performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), we analysed the energetic cost, behavioural cost and physiological cost in A. japonicus. Main results are as follows:

1. Energetic cost and adaptation strategy of sea cucumber Apostichopus japonicus during reproduction

Energetic cost during breeding was explored in the A. japonicus. The food intake, digestive functions, and energy budget patterns were estimated at different breeding stages. Unexpectedly, in the growing gonad phase of the sea cucumber lifecycle, animals showed a decline in feed consumption (from 4.49 g ind^-1 day^-1 to 2.6 g ind^-1 day^-1), ingestion rate (from 0.4 g g^-1 day^-1 to 0.13 g g^-1 day^-1), and apparent digestive rate (from 14.73% to 10.92%), resulting in a reduced energy input. In addition, the increased energy investment in reproduction (from 1.76% to 15.61%) resulted in a decrease in energy allocated to soma growth (from 17.1% to 5.64%) and self-maintenance (from 47.82% to 34.67%). These results suggest that reproduction impairs energy acquisition ability in breeding A. japonicus. And broodstock can adapt energy shortage by internal adjustment of energy allocation strategy.

2. Locomotor cost and adaptation strategy of sea cucumber Apostichopus japonicus during reproduction

Locomotor cost during breeding was explored in the A. japonicus. The total distance moved, cumulative duration of moving, moving frequency and maximum velocity were estimated at different breeding stages. The results showed that reproduction had no negative effects on locomotion frequency or maximum velocity. However, the total distance moved (from 32.04 m to 15.82 m) and cumulative duration of moving (from 12 h to 6.46 h) gradually decreased. Therefore, the results suggest that loss of locomotor endurance is the behavioural cost for reproduction in female A. japonicus. In addition, metabolism in muscle tissue of animals between the non-breeding stage and the growth stage was tested with ultra performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). There were 10 significant metabolic changes found in the muscle tissue of animals in the growth stage. Nine of these (e.g. lysoPCs and L-octanoylcarnitine) were higher during the growth stage and only one (e.g. lysoPE) was higher during the non-breeding stage. These data suggest that oxidative stress and lipid metabolism are potential physiological mechanisms linking reproduction and depressed locomotory performance during reproduction. And behavioral flexibility plays key role in adapting to negative consequences resulting from reproduction.

3. Cost of metabolic physiology and adaptation strategy of sea cucumber Apostichopus japonicus during reproduction

Metabolic cost during breeding was explored in the A. japonicus. The oxygen consumption rate, respiratory rate and enzyme activity of respiratory tree were estimated between non-breeding stage and the breeding stage. The results showed that oxygen consumption rate (from 11.84 μg g^-1 h^-1 to 23.34 μg g^-1 h^-1) and respiratory rate (from 6.22 breaths per min to 10.15 breaths per min) increased significantly at breeding stage. The ATP content in respiratory tree decreased at breeding stage, however, the Na⁺/K⁺-ATPase enzyme activity of respiratory tree increased at breeding stage. In addition, metabolism in respiratory tree tissue of animals between the non-breeding stage and the growth stage was tested with UPLC-Q-TOF-MS. There were 23 significant metabolic changes found in the respiratory tree tissue of animals in the growth stage. 13 of these (e.g. deoxycorticosterone) were higher during the growth stage and 10 of these (e.g. eicosatrienoic acid) were higher during the non-breeding stage. These data suggest that oxidative stress is the potential physiological mechanisms linking reproduction and elevated respiratory performance during reproduction. And behavioral flexibility and physiological flexibility play key role in adapting to high oxygen demand during reproduction.

4. Cost of digestive physiology and adaptation strategy of sea cucumber Apostichopus japonicus during reproduction

Physiological cost during breeding was explored in the A. japonicus. The feces mass, carbon content of feces, nitrogen content of feces and enzyme activity of gut tissue were estimated at different breeding stages. The results showed that carbon (from 1.66% to 2.68%) and nitrogen (from 0.39% to 0.48%) content of feces increased significantly at breeding stage, suggesting that reproduction depress digestive ability in A. japonicus. The activities of amylase enzyme (from 2.96 U mg^-1 protein^-1 to 1.41 U mg^-1 protein^-1) and trypsin enzyme (from U mg^-1 protein^-1 to 42.78 U mg^-1 protein^-1) decreased significantly at breeding stage, suggesting that reproduction depress digestive physiology in A. japonicus. In addition, metabolism in respiratory tree tissue of animals between the non-breeding stage and the growth stage was tested with UPLC-Q-TOF-MS. There were 31 significant metabolic changes found in the gut tissue of animals in the growth stage and mature stage. 8 of these (e.g. serotonin and lysoPCs) were both higher during the growth stage and mature stage. However, 4 of these (e.g. uridine monophosphate) were both higher during the non-breeding stage. These data suggest that oxidative stress and gut degradation are the potential physiological mechanisms linking reproduction and depressed digestive performance during reproduction. And feeding preference may play key role in adapting to high nutrient demand during reproduction.