| Turtles are special aquatic economic animals,which are deeply loved by people because of rich nutrition and medicinal value.Due to the low survival rate and slow growth of the turtles when cultured outdoors,they are usually reared in the greenhouse during the seedling period.However,the indoor environment is generally dark or low light.How to ensure the welfare of turtles when cultured in the greenhouse is not only a difficult problem in production management,but also a key scientific problem that needs to be solved to realize the welfare of turtles.In this study,a breeding system is designed based on the characteristics of the greenhouse environment and the living habits of turtles.At the same time,the simulated solar lamp(self-ballasted mercury vapor lamp)is used as the light source to explore the influence of photoperiod on the growth performance,digestive enzyme activity,stress response and liver antioxidant status of the Chinese soft-shelled turtle,the influence of different lighting modes on the growth performance,stress response,liver antioxidant status and basking behavior of the Chinese soft-shelled turtle,the influence of lighting modes on the growth performance,serum cortisol level and liver antioxidant status of juvenile Chinese three-keeled pond turtle cultured in greenhouse and the influence of light intensity on the growth,stress,immune performance and liver antioxidant status of the Chinese soft-shelled turtle.The purpose of this thesis is to explore the effects of light on the growth,behavior and physiology of turtles cultured in greenhouse,in order to provide a scientific basis for the regulation of light in the greenhouse.The main content and conclusions of this study are listed as follows:1.In order to explore the relationship between the photoperiod and the growth and physiology of the Chinese soft-shelled turtle,turtles were reared under three photoperiods,0L:24 D,6L:18D and 12L:12D(L:Light,D:Dark).According to the living habits of the Chinese soft-shelled turtle,the experimental system has set up a basking area and a water area.During the experiment,the mode of lighting the full tank is adopted.Therefore,both the basking area and the water area have light.The light intensity of the basking area is 3.25±0.02 W/m~2(320-960 nm,the same below)and UVB light intensity is0.21-0.27 W/m~2.The light intensity of the water area is 4.58±0.22 W/m~2and UVB light intensity is 0.48-0.52 W/m~2.Water temperature is controlled at 30±2℃.After the Chinese soft-shelled turtle was reared in the system for 123 days,its growth performance and physiological state data were analyzed.Results showed that differences in growth were insignificant during the experiment.When the photoperiod is 0L:24D,the survival rate of Chinese soft-shelled turtle is 99.44%,which is significantly higher than that of the 12L:12D group.When the photoperiod was 0L:24D,the trypsin activity of soft-shelled turtle was significantly higher than that of the 6L:18D group,and the lipase activity was significantly higher than that of the 12L:12D group,but there was no significant difference in amylase activity between the groups.In the 0L:24D photoperiod,the serum cortisol content was significantly lower than the other groups,but the photoperiod had no significant effect on the serum lactic acid content.For the antioxidant enzyme activity of the Chinese soft-shelled turtle liver,under the 0L:24D photoperiod,the T-AOC was significantly lower than the other groups,the SOD activity was significantly higher than the other groups,and the GSH-PX activity was significantly lower than the 12L:12D group.The content of MDA under 6L:18D photoperiod was significantly higher than that of other groups.With the extension of photoperiod,MDA showed a trend of first rising and then falling.Although the photoperiod had no significant effect on the growth performance of Chinese soft-shelled turtle,the physiological state of Chinese soft-shelled turtle under different photoperiods showed significant differences.Therefore,in this study,based on the background of lighting the full tank,a longer photoperiod will adversely affect the physiological status of the Chinese soft-shelled turtle.2.In view of the mode of lighting the full tank,a longer photoperiod has an adverse effect on the physiological state of the Chinese soft-shelled turtle.In this context,a dark environment(NL)and three different lighting modes(lighting the basking area and water area simultaneously,LBW;light the water area only,LW;light the basking area only,LB)were set to explore the effects on the growth performance,physiological status and basking behavior of the Chinese soft-shelled turtle.In the experiment,the light intensity of the basking area is 3.25±0.02 W/m~2and UVB light intensity is 0.21-0.27 W/m~2.The light intensity of the water area is 4.58±0.22 W/m~2and UVB light intensity is 0.48-0.52W/m~2.Water temperature is controlled at 30±2℃.After 123 days of rearing,the growth performance and physiological status of the Chinese soft-shelled turtle were analyzed.Results showed that there were no significant effects on the growth performance of the Chinese soft-shelled turtles.The lighting mode has a significant impact on the survival rate of Chinese soft-shelled turtle.Among them,the survival rate of Chinese soft-shelled turtle is the lowest in LBW group,which is significantly lower than that of NL group.There were no significant differences in survival rate of Chinese soft-shelled turtle between LB group,LW group and NL group.Regarding the stress response,the serum cortisol content of LB group and NL group was significantly lower than other groups,and the glucose level of LB group was the lowest,which was significantly lower than that of NL group and LW group.The lighting mode had no significant effects on serum lactic acid level.Regarding the liver antioxidant status and immune-related indicators of the Chinese soft-shelled turtle,the T-AOC in LB was significantly lower than that in LBW,the GSH-PX activity in LB was significantly lower than that in the other groups,and the C3 content of the LB group was significantly higher than that of the NL group.Therefore,for Chinese soft-shelled turtles in the greenhouse,lighting the basking area only(LB)is the best lighting modes for the growth and health of Chinese soft-shelled turtles.By analyzing the basking behavior of the Chinese soft-shelled turtle under different lighting modes for 5 consecutive days,it was found that in the dark environment,the Chinese soft-shelled turtle in greenhouse needed to have the basking 4 hours after eating.In the light environment,the number of Chinese soft-shelled turtles in the group with light reached their peak at 12:00,but the number of Chinese soft-shelled turtles on the basking area in LBW and LB was significantly higher than that in LW.During the light off time period between 0:00-6:00 and 18:00-23:00,the number of Chinese soft-shelled turtles in LB was at a low level,while the number of Chinese soft-shelled turtles in LBW is fluctuating during this period.Based on the basking behavior of the Chinese soft-shelled turtle,it is recommended that lighting the basking area only(LB)is the optical lighting mode for the Chinese soft-shelled turtle in a greenhouse.3.In order to explore whether the influences of different lighting modes on growth performance and physiological status of aquatic animals were species-specific and the best lighting modes for juvenile Chinese three-keeled pond turtle cultured in greenhouse,the turtles were reared in a dark environment(control group,NL)and three different lighting modes(lighting the basking area and water area simultaneously,LBW;lighting the water area only,LW;lighting the basking area only,LB)for 203 days.In the experiment,the light intensity of the basking area and the water area is as same as the parameter of the study on lighting mode of Chinese soft-shelled turtle.Water temperature is controlled at 30±2℃.After the Chinese three-keeled pond turtle was raised for 203days,its growth performance and physiological status data were analyzed.The results showed that no significant differences were observed in weight gain rate in the first 92days of the experiment,while on the 126th days of the experiment,the weight gain rate of the turtle exposed to LW was significantly higher than that exposed to LBW.At the end of the experiment(203 days),the turtle in the LW group exhibited higher weight gain and specific growth rate compared to other treatments.For survival rate,there were no significant differences among the treatments.With regard to cortisol level,there were significant differences among the treatments,and the cortisol level in turtle exposed to LW was significantly lower than that in other treatments.Regarding the oxidative stress,the level of catalase(CAT)in turtle exposed to LW and LB was significantly lower than that exposed to LBW and NL.The malonaldehyde(MDA)activity in turtle exposed to LW was significantly lower compared to other treatments.Synthesizing the effects of lighting modes on the growth and physiology of turtle,it was found that the effects of lighting modes on turtles were species-specific.For Chinese three-keeled pond turtle cultured in a greenhouse,the optimal lighting mode was lighting the water area only.4.In this study,the effects of different light intensities on the growth performance and physiological status of the Chinese soft-shelled turtle were explored with the preferred mode of lighting the basking area only.In the experiment,a dark environment was used as the control group,and three kinds of light intensities were set at the same time,namely the low light intensity group(light intensity:6.56±0.14 W/m~2;UVB light intensity:0.58-0.62 W/m~2),medium light intensity group(light intensity:18.11±0.54W/m2;UVB light intensity:1.15-1.23 W/m~2)and high light intensity group(light intensity:37.81±2.85 W/m~2;UVB light intensity:2.27-2.55 W/m~2).The experimental photoperiod was 12L:12D,and the water temperature was controlled at 30±2°C.After cultivating in the greenhouse for 152 days,it was found that the growth performance of the Chinese soft-shelled turtle in the low light intensity group was significantly higher than that in the high light intensity group.With the increase of the light intensity,the growth performance presented earlier increase and later decrease trend.Regarding the stress response,the serum cortisol level of turtles in the low light intensity group was significantly lower than that in the high light intensity group,and the serum glucose level was significantly lower than that in the dark group and high light intensity group.Regarding the immune performance,in the low light intensity group,the activity of LZM was significantly higher than that in the other groups,the activity of ACP was significantly higher than that in the dark group and high light intensity group,the contents of NO and Ig M were significantly higher than that in the high light intensity group.Regarding the anti-oxidative stress in the liver of soft-shelled turtle,under the condition of low light intensity,SOD activity and GSH-PX activity in the liver of soft-shelled turtle were significantly lower than that in the dark group and high light intensity group.And the CAT activity of turtles in the low light intensity group was the lowest among the treatments.The GSH content was significantly lower in the low light intensity group than that in the high light intensity group.The MDA content was significantly lower in the low light intensity group than that in the dark group and high light intensity group.Therefore,considering the growth performance,stress response,liver anti-oxidative stress and immune performance of the Chinese soft-shelled turtle,it was recommended to provide a lower intensity of light when lighting the basking area only. |
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