| In order to explore the effects of pH, nitrite and light on the growth of Koi Carp and color effects, this experiment studied three elements, the first one is the tolerance test of Koi about the pH and nitrite. The second one is the increase rate, hemoglobin(HB), serum superoxide dismutase(SOD) and alkaline phosphatase(AKP) and skin(containing scale) the change of carotenoid content in class of Koi which were fed with two feeds under the pH and nitrite stress;The third one is to compare the content distribution situation of carotenoid in koi carp skin(containing scale), muscle and hepatopancreas pigment between the koi carp which were fed in light and dark. The results are as follows:1、In this experiment seven pH gradients(the gradient set for pH = 3, 4, 5, 6, 9, 10, 11) and six nitrite gradients(the gradient set 0.1mg / L, 0.2, 0.4 mg / L, 0.6mg/l, 0.8, 1.0 mg / L) were provided for stress. The red and white brocade carp were kept in the gradients for 96 h. The results showed that: All the carps in pH3.0 were killed and the survival rate was 0% within 24 hours. The survival rate of pH4.0 was 58.3%, and no fish were observed death in the other groups. By the time of the experiment, all the carps in pH 4.0 groups were killed in 72 hours. In the high pH value range, the survival rate was significantly higher than that of the low pH experimental group, and the survival rate of the pH11 group reached 83.3% at the end of the experiment. Only the carps in 0.8mg/L group were observe death of a 72 h Nitrite group, and the rest of the experimental composition kept the living rate of 100%. The carps showed a better adaptability in the experiment of alkaline water, the survival rate reached 83.3% when the pH value is 11. And Koi of acidic water adaptability was lower than in alkaline water, at pH values for 5.0 survival rate was 75%, all carps died when the pH was 4.0 and below. This shows that compared to the acidic, koi got better adaptability in alkaline water; The safety pH range which were suitable for carp survival was between 6.0-10.0. In this study no acute harmful broken effects of nitrite of were found about Koi, it suggest that description Koi have a stronger tolerance of nitrite in a short time.2、Three pH gradients(pH 6.0-6.5, pH 7.2-7.7 and pH 8.5 9.0) and three nitrite gradients(0.1 mg / L and 0.25 mg / L and 0.5 mg / L) were setting to feed the carps in this experiment. The red and white brocade carp were kept for 40 days, the growth, physiological index and color effects were compared between those two groups. The results show that the nitrite and pH had significant effect on the growth rate, AKP and SOD, carotenoids and hemoglobin content of Koi carps(P < 0.05). The carps in pH7.2-7.7 groups had the highest rate of weight gain, and were significantly higher than those in pH6.0-6.5 experimental groups(P < 0.05). But there was no significant difference between pH7.2-7.7 experimental groups and pH8.5-9.0 experimental groups(P > 0.05); The carotenoid pigment content, serum AKP, SOD content in pH6.0-6.5 experimental group were significantly lower than those of the other two groups. At the same time the results showed that tolerance capability of Koi was better in alkaline environment than the acidic environment. The growth and body color of Koi were subjected to significant influence in pH6.0-6.5; In the nitrite experiment, the weight rate, carotenoid pigment content, serum alkaline phosphatase(AKP) superoxide dismutase(SOD) and the content of hemoglobin content of Koi showed a decreasing trend with the increase of the concentration of nitrite. The index of carps in 0.5 mg / L group were significantly lower than in 0.1 mg / L group. And the methemoglobin ratio showed a rising trend, it was significantly higher in 0.5 mg / L group than that in 0.1 mg / L group. The results showed that the koi on nitrite concentration increase with some stress ability, but with the increase of nitrite concentration, growth and immune would be inhibited and it would lead to color variation beyond the stress ability.3、The light(light intensity is equal to or larger than 500lx) and dark(light intensity is less than or equal to 100lx) condition were used to explore the impact of light on the coy carp skin(including flakes), changes in the distribution of muscle and hepatopancreas of the carotenoid content. The results showed that the carotenoid pigment content in skin did not appear significant change in light condition(P > 0.05), and the carotenoid pigment content in skin of dark condition showed a significantly decreased(P < 0.05). And the carotenoid pigment content in muscle showed no significant change in light and dark conditions(P > 0.05), there is no significant difference between two different condition(P > 0.05), but the carotenoid pigment content in muscle showed larger fluctuations in dark. the hepatopancreas carotenoid pigment content in light and dark conditions showed no significant change(P> 0.05), at the same time there was no significant difference between them(P > 0.05), indicating that the hepatopancreas carotene content was affected by the illumination condition slightly. The results showed that light illumination condition can influence Koi body carotene distribution, skin and muscle carotenoid content of Koi in dark condition was significantly lower than that in the light condition. |
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