Effects Of Light On The Habitat, Growth And Nutritive Compositions In Muscles Of Plectropomus Leopardus Juveniles

Plectropomus Leopardus, trivial name is Miniatus Grouper, subordinate to Perciformes 、Serranidae 、Epinephelinae, and is belong to a Warm water reef fish.Mainly distributed in the Western Pacific Ocean to the India ocean, but the number of rare. Plectropomus leopardus has a very high economic value for its nutritional and delicious flesh, has the characteristics of low fat, low cholesterol, and high protein, it belongs to high grade edible fish, loved by consumers, and because the body color gorgeous, also can be used as ornamental fish, wide prospect of market.Physiological index of fish habitat, feeding, growth, survival and muscle nutrient composition under the influence of various environmental factors, the color of the light environment is one of the important factors affecting fish visual system, feeding growth and physiological and biochemical indexes, creating suitable breeding environment, reduce stress and promote fish growth and improve the nutritional value of fish is an important problem must be considered in the production of factory farming. A comprehensive understanding of the interaction between the color of the light environment and Plectropomus Leopardus, for Plectropomus Leopardus has an important guiding significance to the production practice.The experiment was directed by eco-nutrition, physiology, and biochemistry knowledge and other disciplines theory and the method as the instruction, to indoor circulating water aquaculture Plectropomus Leopardus juvenile fish as object, and had three main parts experiments. Part 1 has explored the Plectropomus Leopardus juvenile fish under white, blue, green, yellow and red five kinds of light qualitative selectivity and the habitat characteristics under different light gradients; And then,selected the three primary colors(red, green, blue), explored the different light quality(red blue, A1, A2, A3), light cycle(16 l: 8 d, B1; 12 l: 12 d, B2; 8 l: 16 d, B3) and light intensity(1000 lx, C1; 1500 lx, C2; 2000 lx, C3) in the circulating water aquaculturesystem Plectropomus Leopardus juvenile fish live interaction of three factors; Part 2has studied the effect of different light colors on survival, growth and feeding of Plectropomus Leopardus juveniles fish; Part 3 has studied the effect of different light colors on nutritive compositions in muscles of Plectropomus Leopardus juveniles; We got the following experimental results by 120 days trial, measuring of breeding observation, physiological index, biostatistics analysis.1. Effects of Different Types of Light on Habitat of Plectropomus Leopardus JuvenilesThe results revealed that the light quality and light intensity also had significant difference on the distribution rate of juveniles fish. Under the condition of the range of light quality and light intensity, with the rising of light intensity in the same intensity of light, the juvenile fish became less and less sensitive to the intensity of light, and under different intensity of light, the distribution rate had no significant difference(P>0.05).With the same intensity of light, the longer wavelength was, the higher rate the juvenile fish distributed, with the rising of light density, the juvenile fish became less and less sensitive to the wavelength of light, but the distribution rate had significant difference under different wavelength of light(P<0.05). Orthogonal test results show that the light quality had significant difference to the distribution rate of juvenile fish(P<0.05),but the photoperiod and light intensity had no significant difference(P>0.05). Variance analysis results show that the preferable environment light group of the habitat of juvenile fish are light quality: green light; photoperiod:16L: 8D; light intensity: 1500 lx. And the main factor is light quality, light followed by light intensity and photoperiod.2. Effects of light colors on growth performance and nutritive compositions in muscles of Plectropomus Leopardus juvenilesFirst. The high strength feeding intensity(0.995 %.d-1), the higher feed conversion rate(85.767 %) and the lowest bait coefficient(1.166±0.034) of juvenile fish occurred under green light conditions. But the feeding of the juvenile fish was no significant difference(P>0.05) under different light color. Second. The growth of the juvenile fish was no different under different light color. The growth of the juvenile fish in green light is significantly obvious, and the weight gain higher in black than it before 30 days of cultured days. But the weight gain faster in green light after 30 days of cultured days,as the extension of breeding time, the significantly increased of juveniles weight growth between each light color after 30 days of cultured days(P< 0.05). Third. But the condition factor(CF) in different light treatment groups were not significant difference(P>0.05). Fourth, The lowest survival of the juvenile fish is 50% which occurred under white light, the survival rate of other four light groups are all over 80%,and the maximal survival of juvenile fish is 88.33% which occurred under green light.In conclusion, the juvenile fish may survival, growth and feeding better under green light color in indoor circulating water aquaculture production.3. Effects of light colors nutritive compositions in muscles of Plectropomus Leopardus juvenilesAccording to the nutritive compositions in muscles of Plectropomus Leopardus juveniles under five light colors environment, moisture content: the highest is white light color group(79.26±2.17%), the lowest is yellow light color group(78.04±0.42%);ash content: the highest is yellow light color group(1.65±0.04%), the lowest is white light color group(1.35±0.05%); crude lipid content: the highest is red light color group(2.69±0.69%), the lowest is green light color group(1.98±0.95%); crude protein content: the highest is green light color group(25.47±1.82%), the lowest is red light color group(23.35±0.37%), above which show no significant difference(P>0.05).The essential amino acid index(EAAI) of juveniles under five light colors environment from highest to lowest in turn to yellow(68.132)>red(67.727)>green(67.275)>white(62.845) >black(60.351). There are 7 kinds of delicious amino acids were detected in this study, from highest to lowest on the total content of sweat amino acids(Asp, Glu,Arg) are, in order, green, white red, black and yellow; of the umami amino acids(Gly,Ala)are, in order, white,yellow red, black and green; of the aroma amino acids(Try,Phe)are, in order, black, green, yellow red and white; The highest total amino acids content is sweat amino acids(63.03% ~63.54%),the second is umami amino acids(21.31% ~ 22.08%), the last is aroma amino acids(14.38% ~ 15.27%).The Plectropomus Leopardus juveniles grow better in green color environment according to the indicators ofgrowth efficiency, muscle nutrition and taste evaluation.In conclusion, the results indicated that: light environment is one of the important light environment factors influence physiological ecology indicator such as habitat,growth and muscle nutrients of Plectropomus Leopardus juveniles. In the light of the three main environmental factor conditions, the most obvious factor affecting the habitat of Plectropomus Leopardus juveniles is light color, followed by light intensity,the last is the photoperiod. The juvenile fish may survival, growth and feeding better under green light color in indoor circulating water aquaculture production. Under dark condition and natural light to illuminate, juveniles fish are lower than the indicators there is light color environment groupAt last, the researches have obtained the parameters of habitat, feeding, growth,survival rate, muscle nutrients and source of Plectropomus leopardus juvenile in industrial culture, determined the preferred solution for the cultivation mode, and figured out the specific physiological mechanism preliminary and light color of high habitat, fast-growing and hyperalimentation of Plectropomus leopardus juvenile. In addition, they had improved the technologies and benefits of culturing the fish in recirculating system, and promoted its healthy and sustainable development.