| Light is one of the key environmental factors that influence the behavior,food intake,growth and development of aquatic organisms.Litopenaeus vannamei is the largest scale and yield of crustaceans in China,with important economic value,its culture mode is mainly pond culture.In recent years,there are many advantages in indoor factory farming,such as strong controllability,high efficiency of farming,little impact from the external environment,and year-round continuous production,have been gradually recognized by the industry and have become one of the important development directions of future aquaculture.In our country,the factory culture mode of L.vannamei has also been promoted rapidly.However,compared with the traditional open pond culture,the factory plants block the natural light.Therefore,the implementation of artificial light supplement in the process of the factory culture of prawn has become an important technical means.But so far,achieved factory farming mode suitable for light environment regulation strategy still has not been established.As a new type of light source,the advantage that LED replace traditional light source is remarkable.In this paper,by simulating factory farming lighting environment,study the effects of LED light on growth,feeding,oxidative stress responses,digestion and metabolism of L.vannamei,analyze its effect law,in order to provide the theoretical basis for the construction of suitable lighting strategy for the factory farming for L.vannamei.The main research contents and results are as follows:1.In this experiment,five different LED spectral composition environments including full spectrum,white light,blue light,green light and yellow light were selected as supplementary light sources,to study the effects of different spectral composition on growth,molting,digestive and metabolic activities of L.vannamei.The results showed that the final weight,weight gain,weight gain rate and SGR of L.vannamei exposed to blue light were significantly higher than those of the other light environment groups(P<0.05),followed by the green light group,and there were no significant difference between the full spectrum,white light and yellow light groups.The blue group had the highest number of molting times,followed by green group,and white group was the lowest.Compared with other light groups,blue light significantly increased pepsin activity in the intestine of shrimps(P<0.05).The activities of trypsin and lipase in the intestine of shrimps under blue and green light were also significantly higher than those in other groups(P<0.05).The Na~+-K~+-ATP activity in the intestine of shrimp in blue light group was significantly higher than that in full spectrum,white light and yellow light groups(P<0.05),but there was no significant difference between the other groups.In this experiment,the amylase activity of shrimp was not affected by the different spectral compositions.LDH activity of blue light and green light groups was significantly lower than that of the full spectrum,white group and yellow light groups(P<0.05),while SDH of blue light and green light groups was significantly higher than that of other groups(P<0.05),and SDH activity of yellow light group was the lowest(P<0.05).The activity of HK and PK in blue light group was significantly higher than that in the other groups(P<0.05).The results showed that compared with other spectra,short-wavelength blue and green light could improve the digestive and metabolic activity of L.vannamei,promote molting and facilitate growth.2.Early research has shown that blue wavelengths can promote growth in the process of breeding,so this study selected blue light as supplement light source,2 W/m~2?4 W/m~2?6 W/m~2?8 W/m~2?12 W/m~2and 24 W/m~2six kinds of blue light intensity were set to study the effects of light intensity on growth feeding,molting,oxidative stress,digestion and metabolism activity of L.vannamei.The study found that when the blue light intensity was 6 W/m~2,the final weight,weight gain rate,SGR and FI of the shrimp were significantly higher than those of the other groups(P<0.05),and 24 W/m~2was the lowest,which was significantly lower than that of other light intensity groups(P<0.05).The FCR of the 6 W/m~2group was significantly lower than others(P<0.05),and the FCR of the 12 W/m~2group was significantly higher than others(P<0.05).The total molting times in 6 W/m~2and 8 W/m~2groups were significantly higher than those in the other groups,and the molting synchronicity were the best.The blue light intensity can significantly affect the activities of glucose,cholesterol,triglyceride,GOT and GPT in the haemolymph of L.vannamei.With the increase of light intensity,the activity of cholesterol,triglyceride and glucose in the haemolymph of shrimp decreased,especially in the 12 W/m~2and 24 W/m~2groups(P<0.05),while the difference between the 2 W/m~2,4 W/m~2and 6 W/m~2groups was not significant.On the contrary,the activity of GOT and GPT in shrimp haemolymph increased with the increase of light intensity,which was significantly increased in the 12 W/m~2and 24 W/m~2groups(P<0.05).The activity of antioxidant enzymes(SOD,GSH and CAT)in the haemolymph of L.vannamei showed a tendency of first increasing and then decreasing with the increase of light intensity,and reached the peak when light intensity was 6 W/m~2,the lowest when light intensity was 24 W/m~2(P<0.05).Under different light environments,the activity of pepsin,amylase,trypsin and lipase in the intestine of L.vannamei increased first and then decreased with the increase of blue light intensity,and the peak appeared in the 6 W/m~2group(P<0.05).With the increase of light intensity,LDH activity increased significantly and reached the peak in the 24 W/m~2group(P<0.05),while SDH activity decreased significantly and reached the minimum in the 24 W/m~2group(P<0.05).With the increase of light intensity,the HK and PK activities in the hepatopancreas of shrimp increased first and then decreased,reaching the peak in the 6 W/m~2group(P<0.05)and the minimum in the24 W/m~2group(P<0.05).3.By previous research we found that the 6 W/m~2blue wavelengths promote growth and feeding of L.vannamei in breeding process,so this study selected 6 W/m~2blue light as supplement light source.Five light photoperiod 0L:24D?8L:16D?12L:12D?16L:8D and 24L:0D were set to study the effects of light photoperiod on growth feeding,molting,oxidative stress,digestion and metabolism activity of L.vannamei.The results showed that the photoperiod had similar effects on the final weight,weight gain,weight gain rate,SGR and FI of L.vannamei,all of which were significantly higher in the 24L:0D group than in the other groups(P<0.05).In addition,SGR in 12L:12D and 16L:8D groups was significantly higher than that in 0L:24D and 8L:16D groups(P<0.05).The FCR of shrimp in the 24L:0D group was the lowest(P<0.05),while the FCR of shrimp in the 24L:24D,8L:16D and 16L:8D groups were significantly higher than that in the12L:12D group(P<0.05).The total number of molting times in group 24L:0D was significantly higher than that in other groups.Different blue light photoperiod had no significant effect on the activities of glucose,cholesterol,triglyceride,GOT and GPT in the haemolymph of L.vannamei,but the total cholesterol in the haemolymph of L.vannamei in the 24L:0D group was significantly lower than that in the other groups(P<0.05).The effect of photoperiod on oxidative stress activity in the haemolymph of L.vannamei was not significant,but the GSH and CAT activity in the haemolymph of L.vannamei was significantly lower than that in the other groups(P<0.05).Except for the 0L:24D group,the pepsin,amylase,trypsin and lipase in the intestine of the other groups increased with the extension of light duration.LDH activity in the hepatopancreas of shrimp reaching the peak in the 8L:16D group(P<0.05),and there was no significant difference between0L:24D,16L:8D and 24L:0D groups(P>0.05).The SDH activity of 24L:0D group was significantly higher than that in 12L:12D group(P<0.05),and the activity of 0L:24D group was the lowest(P<0.05).HK and PK activity in the hepatopancreas of shrimp,reaching the peak in24L:0D(P<0.05),but there was no significant difference between the other groups.4.To study the effect of blue light on the molecular mechanism of the growth in L.vannamei.We carry out the breeding experiment for 30 days under the three different light environments including full spectrum,blue light and dark.The shrimp hepatopancreas were collected for the transcriptome analysis after the experiment.The results showed that a total of 2174 DEGs were obtained from the hepatopancreas.By comparing,we found that a total of 28 DEGs were collected in the full spectrum and blue light group,and significantly lower in the blue light and dark group(975),and the full spectrum and dark group(1171)(P<0.05).All DEGs were analyzed for GO,and the genes were divided into 23 branches under three broad categories:biological processes,cellular components,and molecular functions.There are 12 branches in the biological process group,among which cell process,single tissue process and biological regulation account for the highest proportion.There were 8 branches in the cell group,among which cells,cell components and organelles accounted for the highest proportion.There are three branches in the molecular functional grouping,including binding,catalytic activity and structural molecular activity.KEGG pathway annotation analysis showed that DEGs involved 38 KEGG pathways,and the pathways with the highest gene number included cytochrome P450 exogenous drug metabolism pathway,cholesterol metabolism,glyceride metabolism,cell endocytosis pathway,lysosomal pathway,folate synthesis pathway,MAPK signaling pathway,etc.AKR1B,GSH,AMY,MALZ,BMPR and AO(S)-2 in the hepatopancreas of L.vannamei after 30 days of full spectrum,blue light and dark irradiation were analyzed,we found that blue light environment can improve the expression of AKR1B,GPX and AMY genes in the hepatopancreas of L.vannamei to a certain extent,and reduce the expression of MALZ,BMPR and AO(S)-2 genes,so as to promote lipid metabolism,glucose metabolism and the growth and development of exoskeleton of L.vannamei,to enable the healthy and rapid growth of L.vannamei.These results are favorable for the research on the growth metabolomics of L.vannamei under the influence of light environment. |
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