The Effect Of Some Ecological Factors On The Growth Rate, Biochemical Component And Energy Density Of Paralichthys Lethostigma Hatchlings

Paralichthys lethostigma originally grows in the America, and the fish is equipped with the following advantages of growing quickly, resisting strongly and having tasty meat. It is very favored in the international market, and has been a new eminent seed in China since being introduced. Using the population biological methods, the effect of some ecological factors (dietary levels, temperature, salinity ) on the growth rate, biochemical component and energy density of the juvenile and young of Paralichthys lethostigma has been studied, and the main results are as follows:1. The relation between specific growth rate and dietary levels of the juvenile and young of Paralichthys lethostigma can be described as straight line and the parabolic relation, in which the parabolic relation is more equal. The results show that their specific growth rates increase with the rise of dietary levels, and when the dietary levels exceed the limit, the specific growth rate descend with rise of dietary levels.2.The linearity relation of between the temperature and dietary level indicates that the temperature significantly affects the specific growth rate of juvenile of Paralichthys Lethostigm with 1% of dietary level (P < 0.01). However, the temperature does not remarkably affect the specific growth rate with hungriness and 4% of dietary level(P>0.05).3. The specific growth rate of young of Paralichthys lethostigma tends to raise with the increase of the salinity athough the salinity (4.16 ~20.80‰) can not significantly affect the specific growth rate (P>0.05). When the salinity is at 20.80‰, the specific growth rate increase to a peak value.4. After hungriness, the body weight of all juvenile and young of Paralichthys lethostigma descended. Their specific growth rate is negative, in which the juvenile is more remarkable.5. The linearity relation between the dietary levels, the fat content, the protein content and energy density of the juvenile and young of Paralichthys lethostigma is significantly positive (P<0.05). The linearity relation between water content and ash content is significantly negative (P<0.05).6.The linearity relation between water content of the young of Paralichthys lethostigma and temperature is significantly negative (P<0.01). The linearity relation between the ash content and temperature is significantly negative also((P<0.01). However, the linearity relation between the energy density and temperature is not significantly (P>0.05), and the temperature affects the fat content and the protein content with no certain regularity.7.The salinity can significantly affect water content, the fat content, the protein content of the young of Paralichthys lethostigma(P<0.01), but can not significantly affect the ash content and the energy densit(yP>0.05). The linearity relation between the water content and the salinity is significantly negative(P<0.01), and the linearity relation between the salinity, fat content and the protein content is significantly positive (P<0.01).8.The linearity relation between the water content, fat content and the protein content of Paralichthys lethostigma is significantly negative (P<0.01), but the relations between the water content, ash content and the energy density are not significan(tP>0.05). The results show that the water content may be used to estimate the fat content and the protein content of Paralichthys.Paralichthys lethostigma is an excellent new breed. In this paper, the effect of dietary levels, temperature and salinity on the growth rate, biochemical component and energy density of the juvenile and young of Paralichthys lethostigma has been studied, and the relationships between the biochemical components, example for the fat content , the protein content, the ash content and the water content, have been discussed. That the water content may be used to estimate the fat content and the protein content of Paralichthys has been found. The results above may enrich the basic data of energetic biology and ichthyology and can facilitate the healthy breeding of Paralichthys lethostigma.