不同光色对花鲈生长、摄食、分布及代谢的影响

Effects of different light colors on growth, feeding, distribution and metabolism of Lateolabrax maculatus

中文关键词: 花鲈  光色  生长  行为  代谢组

英文关键词: Lateolabrax maculatus  Light color  Growth  Behavior  Metabolome

中文摘要:

      光照是影响鱼类生长发育的关键环境因子之一。本研究设置了蓝、绿、黄、自然光4种光色组,在相同光强和光周期条件下养殖花鲈(Lateolabrax maculatus)45 d,探究不同光色对花鲈生长、摄食、分布及生理代谢的影响。结果显示,蓝光组花鲈幼鱼的体质量增长率(WGR)和特定生长率(SGR)(45.70±2.20%、0.90±0.08%.d-1⁾显著高于黄光组和对照组(P<0.05),其肝脏胰岛素生长因子(igf-1、igf-2)和生长激素受体1(ghr-1)基因相对表达水平与自然光组相比有所升高。花鲈幼鱼对不同光色的趋光性分布不同，对蓝光表现出正趋光性,而对黄光表现出负趋光性。代谢组学分析表明,蓝光组花鲈主要通过L-异亮氨酸和溶血磷脂酰乙醇胺(LPE,18:2/0:0)等代谢物显著上调影响氨基酸代谢和甘油磷脂代谢等9条通路(P<0.05),进而影响氨基酸和磷脂类物质的合成；绿光组主要通过富马酸、L-酪氨酸等代谢物显著下调影响花鲈苯丙氨酸代谢和氧化磷酸化等5条通路(P<0.05),进而影响鱼体蛋白质合成和激素分泌。本研究表明，蓝光条件可以有效促进花鲈幼鱼的生长，降低饲料系数，加快氨基酸和磷脂类合成进程，研究结果为花鲈养殖过程光色选择及养殖策略的制定提供了理论依据。

英文摘要:

      Lateolabrax maculatus belongs to the order Perciformes, which is distributed in the coastal waters and estuaries of China, Japan and the Korean Peninsula. Its muscle protein is rich in amino acids, and contains many high-quality amino acids necessary for human body, which has extremely high edible value. L. maculatus has the advantages of wide temperature, wide salt and rapid growth, and is suitable for various culture modes such as cages, ponds and factories. It is an important marine economic fish in China. Light is one of the key environmental factors that affect the behavior and physiological and biochemical indexes of fish. In the practice of aquaculture, optimizing the growth environment of fish by controlling different light colors conditions can significantly improve the efficiency of aquaculture. The results show that different light colors have significant effects on the growth, feeding and physiology of cultured fish. For example, the specific growth rate of Juvenile turbot is the highest under the condition of cold white light source, while the specific growth rate is the lowest under the condition of red light source. The digestive enzyme activity of Pseudosciaena crocea in green light was significantly higher than that in blue light group, yellow light group and full spectrum group, and the growth rate was the fastest. The expression of growth-related gene gh in fugu rubripes was the highest under blue light, which was significantly higher than that in yellow light and white light groups. However, it is not completely clear what kind of light color the L. maculatus adapts to and the influence mechanism of different light colors on its growth, feeding, distribution and metabolism. In order to explore the effects of different light colors on the growth, feeding, distribution and physiological metabolism of juvenile L. maculatus were discussed by setting indoor natural light, blue light, green light and yellow light, with the aim of clarifying the relationship between light color and the growth of L. maculatus, determining the optimal light color for the culture of L. maculatus, and providing theoretical basis for the optimization of artificial culture technology and environmental regulation. Four light color groups, blue, green, yellow and natural light, were set up in the experiment. Two circles of light strips were fixed around the bottom of each experimental pool to provide light sources. The distance between the light strips was 15cm, and the light intensity was subject to the measured value of 5 cm above the water center. The light intensity is about 300 lx, and the light period is 12 h light: 12 h darkness. During the experiment, the compound feed was fed twice every day at 8:00 and 18:00, and the single feeding amount was 1.5-2% of the total weight of the sea bass in the pond. After each feeding for 1 hour, the residual bait and feces were cleaned up. The video monitoring equipment (Hikvision camera, Smart265) was placed above the experimental pool, and the time from the first experimental fish to the fish's end of feeding was recorded. During the experiment, the feeding time was measured every five days. The video camera was used to record the distribution of L. maculatus in the experimental pond for 30 minutes before and after feeding. The statistical method of experimental video was used for data processing. The video was captured according to the nodes per minute, and 60 pictures were taken for each processing. All the pictures of L. maculatus were manually marked according to the division area (black dots represent the location of L. maculatus), and compared with the video to ensure the accuracy of the location of L. maculatus. L. maculatus was cultured for 45 days to explore the effects of different light colors on the growth, feeding, distribution and physiological metabolism of L. maculatus. The results showed that the weight growth rate (WGR) and specific growth rate (SGR) of juvenile L. maculatus in blue light group (45.70±2.20%, 0.90±0.08%·d-1) were significantly higher than those in yellow light group and control group (P<0.05), and the feed coefficient of L. maculatus in blue light group was the lowest. The relative expression levels of insulin growth factor (igf-1, igf-2) and growth hormone receptor 1(ghr-1) genes in the liver of L. maculatus in blue light group were higher than those in natural light group. The phototaxis distribution of juvenile L. maculatus is different for different light colors, showing positive phototaxis for blue light and negative phototaxis for yellow light. Metabonomics analysis showed that the blue light group of L. maculatus was significantly up-regulated by metabolites such as L- isoleucine and lysophosphatidylethanolamine (LPE, 18:2/0:0), which affected nine pathways such as amino acid metabolism and glycerol phospholipid metabolism (P<0.05), and then affected the synthesis of amino acids and phospholipids. In the green light group, fumaric acid, L- tyrosine and other metabolites were significantly down-regulated, which affected five pathways such as phenylalanine metabolism and oxidative phosphorylation (P<0.05), and then affected protein synthesis and hormone secretion of sea bass. No significant enrichment pathway was formed in yellow light group. In conclusion, the relative expression levels of igf-1, igf-2 and ghr-1 of L. maculatus could be improved by blue light illumination, and the contents of L-isoleucine and lysophosphatidylethanolamine (LPE, 18:2/0:0) could be significantly increased by blue light treatment, which affected amino acid metabolism, glycerophospholipid metabolism and other metabolic pathways, thus increasing the speed of substance synthesis in L. maculatus, and further significantly improving its growth. Combined with the distribution behavior of L. maculatus in the culture pond tends to blue light, it shows that L. maculatus is suitable for culture under blue light. The results provide a theoretical basis for the selection of light color and the formulation of culture strategy for L. maculatus.