| As an important component of light,the spectrum plays an important role in regulating the physiological functions of fish such as feeding,growth,metabolism,reproduction,and endocrine.Acrossocheilus fasciatus is a indigenous brook fish,but there is a phenomenon that the growth is relatively slow and the development of the male and female gonads is not synchronized.Therefore,the present study investigated the effect of Spectral preference,growth,gonadal development,oxidative defense ability,related hormone and aromatase gene expression of the fish by illuminating with five specific wavelength LED of white(full spectrum)(control),red(632 nm),yellow(593 nm),green(518 nm),and blue(463 nm).The main results are as follows:(1)The study explore the response of stress behavior and adaptive behavior of A.fasciatus to the specific spectral-wavelength at daytime and nighttime,respectively.The results showed that there was no significant difference in the distribution rate of the fish under different spectral conditions during the 20th min daytime(P>0.05).However,the distribution rate in the green and dark regions at nightime was significantly higher than that in the red and yellow regions(P<0.05).With the prolonged exposure time,the fish prefered blue light more than white and green light during the day,while the yellow light has a clear avoidance effect on it.At nightime,The fish prefered blue light to a higher degree,and had the lowest degree of preference for red and yellow light.(2)The spectrum has a significant effect on the growth of the fish.The specific body weight growth rate(SGRw)and gain rate(GR)in the blue light group are significantly higher than those in the control,red light,and yellow light groups(P<0.05).The specific body length growth rate(SGRL)of the yellow group was significantly lower than that of the other groups(P<0.05).In addition,the condition factor(CF)of blue and green light groups were significantly higher than those in the red light and control group in the females.The CF of blue light group was significantly higher than the red light group and the control group in the males(P<0.05).The daily food consumption of red and yellow light groups were significantly lower than that of the blue and green light groups in.And the feed conversion rate(FCR)of red and yellow light groups were significantly higher than that of the blue light group(P<0.05).The above results indicate that short-wavelength spectrum such as the blue light significantly increased the growth and feeding of the fish,and reduced the feed conversion rate.However,the long-wave light induced the opposite effect.(3)The specific spectral-wavelength had different effects on the gonadal development in the fish.Compared with the control group,the yellow light significantly increased the gonadal index(GSI)and the proportion of ?+++ and ?oocytes in the females,while the yellow and green light also significantly promoted the development of the testes(P<0.05).In addition,red light significantly increased female plasma melatonin(MT)level and brain CYP19b gene expression,and green light has the same effect on males.The results showed that the yellow light promoted the development of the females and males gonads of the fish to varying degrees,and the green light had a certain promoting effect on the testis.(4)The specific spectral-wavelength had a significant effect on liver malondialdehyde(MDA)content and superoxide dismutase(SOD)activity only in the males.Compared with the control group,green light significantly reduced MDA content and SOD activity.The result implied green light significantly reduces the oxidative stress of the fish.These research results will provide theoretical basis for rational selection of spectra in the process of industrial breeding of the fish.There are an important theoretical and practical significance for promoting the sustainable and healthy development of industrial aquaculture industry in the study. |
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