Analysis Of The Differences Of Body Color And Pigment Cells And Enzyme Activity In The Plectropomus Leopardus

Plectropomus leopardus,a coral reef fish,shows significantly different body colors in different environments.Its body color is gorgeous and bright,with high ornamental value and high economic value.Plectropomus leopardus is a valuable material to study the development and variation of body color.In this study,Plectropomus leopardus individuals with different colors were selected.The skin color,types of pigment cells and movement state of pigment cells in different parts were observed to compare the red and black Plectropomus leopardus.Then,the skin sections of the individuals with different colors were observed to analyze the influence of the number and distribution of pigment cells on the change of body color.At the same time,the skin color and melanin enzyme levels from different fish body parts were detected and analyzed.These experiments revealed the differences in pigment and enzyme levels between the red and black Plectropomus leopardus,and provided a theoretical basis for further study of mechanisms of body color variation.The results are as follows:1.The results showed that there are melanocytes,erythrocytes,yellow pigment cells and iridescent pigment cells in the skin tissues distributed in the fish skin.The morphology of melanocytes and red pigment cells is mainly dendritic,and the local morphology is punctate.The size of melanocytes was 30-50 μM,and that of erythrocytes was 30-40 μM.In the black individuals,the melanocytes in the back epidermis were mainly melanocytes,and the cells were zonal distribution.In the abdomen epidermis of the black individuals,a large number of melanocytes were observed.While in the tail of the black individuals,a large number of melanocytes were mainly distributed,and the cell density was the largest.Some cells were stacked distribution and the tissue color was the deepest.In the red individuals,the dorsal epidermis was mainly composed of red pigment cells.While in the abdominal epidermis,only red pigment cells were observed and a small number of cells scattered in the tissues and the lightest color.In the tail of the red individuals,red pigment cells were widely distributed with a block distribution,and a small number of melanocytes were observed in the tail epidermis.After stress,the morphology of pigment cells changed from dendritic to punctate,and the aggregation of pigment cells led to the darkening of body color.2.The pigment cells were distributed in the loose layer of the dermis.There are great differences in the distribution of pigment cells in different tissues.The distribution of pigment cells in tail and back tissues was dense,forming a continuous pigment strip parallel to the epidermis.In abdominal tissue,the number of pigment cells was less.However,in black individuals,the distribution of local pigment cells was observed and the melanocytes are mainly distributed in blocks.Than,the erythrocytes are distributed in dispersion and the distribution of pigment cells was parallel to the basal layer of epidermis.In the red individuals,skin pigment cells showed irregular distribution that the erythrocytes were mainly distributed and the number of melanocytes is less.3.The black individuals had higher density of melanocytes,higher melanin content and lower melanin enzyme levels,while density of red cells,carotene and carotenoids and melanin enzyme levels was higher in the red individuals.The contents of carotenoids and carotenoids in red individuals were significantly higher than those in black individuals,and the contents of pigment in abdomen were significantly lower than those in other tissues.The melanin content of black individuals was significantly higher than red individuals and the melanin metabolizing enzyme content of red individuals was significantly higher than black individuals.The body color depth of Plectropomus leopardus was found to be related to the aggregation and dispersion of melanin particles and the activity of melanin-metabolizing enzymes.The brightness of body color was related to the content of red cells and the contents of carotene and carotenoids.