| The test simulated fish keep-alive transportation conditions. It studied the influence of water temperature, vibration frequency, MS-222 anesthetic and clove oil anesthetic on largemouth bass during its keep-alive transportation with water. The test aimed to explore the mechanism of transportation stimulation caused death of fish and find out the technical parameters that suitable for largemouth bass to transport with water to reduce the transportation losses of largemouth bass and obtain the maximum economic benefit.The research studied the effects of water tempearature on simulation transporation of largemouth bass. The results showed that critical temperature of largemouth bass was 4℃, but this temperature wasn’t suitable for largemouth bass to transport with water. It should be above 10℃ during short distances transportation(transportation time less than 3 h) and midway transportation(transportation time less than 10 h), and 15- 20℃ during long distances transportation(transportation time more than 10 h) of largemouth bass when transported with water. Environmental stress produced by transportation made transportation water quality deteriorated sharply. The breath frequency of largemouth bass decreased during transportation. Contents of muscle glycogen, fat, protein, etc energy supply substance decreased. Muscle lactic acid content increased at first then it decreased. Muscle p H decreased at first then increased. Serum cortisol content reached a maximum after largemouth bass was transported 3 h then it decreased gradually and trended to stable at last. Activity of aspartate aminotransferase and lactic acid dehydrogenase, contents of urea and glucose in serum all showed a significantly increased.The research studied the effects of vibration frequency on simulation transporation of largemouth bass. The results showed vibration frequency could influence physiological and biochemical characteristics of largemouth bass. The stronger the vibration frequency was, the greater the effects become. Breath frequency of largemouth bass declined after transportation, and the higher the vibration frequency was, the lower the breath frequency become. Transportation led water ammonia nitrogen content and water p H to changing. Even though the fish was transported at low vibration frequency for just a short time, ammonia nitrogen content in water could reach or exceed the tolerance level of fish. After largemouth bass was transported at the vibration frequency of 60 rpm for 3 h, its serum cortisol, aspartate aminotransferase, urea, lactate dehydrogenase, glycogen, lactic acid and muscle p H did not change significants compared with the control group, but when the vibration frequency increased to 100 and 130 rpm, the differences of these indexes gradually became larger compared with control group, and some even had a significant differences. Therefore, in the actual transportion the vibration frequency should be reduced to the minimum strength in control.The research studied the anesthetic effects of MS-222 at the concentration of 10, 20, 30, 40, 50, 60 and 70 mg/L on largemouth bass, then it studied the effects of water temperature at 10, 15, 20 and 25℃ in 20 mg/L MS-222 on anesthetic effects, finally anesthesia simulated transportation test was conducted at 20℃and 20 mg/L MS-222. Anesthesia test results showed: 10- 20 mg/L MS-222 and 20- 25℃water temperature were suitable for largemouth bass anesthesia transportation. Simulated transportation test results showed: The survival rate was 100% after transportation 17 h which had important commercial value, but it dropped to 70% after transportation 24 h, if this was applicated in practical it would suffer a greater loss. Recovery time of anesthetic largemouth bass increased as transport duration increased. The content of ammonia nitrogen in water almost a linearly increased and water p H was also rising after simulation transportation, but they were all significantly lower than those of non anesthesia transport group. Serum cortisol and glucose contents and lactate dehydrogenase activity were significantly higher than that of the initial group after anesthesia. In the transportation process, serum glucose content continued to rise but serum cortisol content had no significant changes. There were no significant difference of serum aspartate aminotransferase, urea and lactate dehydrogenase in the first 10 h transportation then they increased significantly. Muscle glycogen content fell while lactic acid content rose. Muscle p H decreased. The moisture content in muscle did not change significantly in the first 10 h then it rose significantly. Fat and protein contents in muscle reduced continually. The results indicated that adding right amount of MS-222 could reduce the stress reaction of largemouth bass and inhibition fish biochemical changes to some extent, but MS-222 couldn’t prevent transportation damage to fish after long time transportation.The research studied the anesthetic effects of clove oil at the concentration of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0 and 20.0 mg/L on largemouth bass, then it studied the effects of water temperature at 10, 15, 20 and 25℃ in 5.0 mg/L clove oil on anesthetic effects, finally anesthesia simulated transportation test was conducted at 15℃and 5.0 mg/L clove oil. It found that clove oil was similar to MS-222 in anesthesia and anesthesia transportation largemouth bass. Anesthesia test results showed: 2.5- 7.5 mg/L clove oil and 15- 20℃ water temperature was suitable for largemouth bass anesthesia transportation. Simulated transportation test results showed: The survival rate was 100% after transportation 10 h which had a certain commercial value, when continue to transport the survival rate declined, and it dropped to 60% after transportation 24 h, which had little application value. Recovery time of anesthetic largemouth bass increased as transport duration increased. The content of ammonia nitrogen in water almost a linearly increased, but it significantly lower than non anesthesia transport group, and water p H was also rising after simulation transportation. Serum cortisol and glucose contents and lactate dehydrogenase activity were significantly higher than that of the initial group after anesthesia. During transportation, serum glucose content continued to rise but serum cortisol content had no significant changes. There were no significant difference of serum aspartate aminotransferase and urea in the first 10 h transportation then they increased significantly. Serum lactate dehydrogenase showed a rising trend overall. Muscle glycogen content fell while lactic acid content rose. Muscle p H decreased. The moisture content in muscle did not change significantly in the first 10 h then it rose significantly. Fat and protein contents in muscle reduced continually. The results indicated that adding right amount of clove oil could reduce the stress reaction of largemouth bass and inhibition fish biochemical changes to some extent, but clove oil couldn’t prevent transportation damage to fish after long time transportation. |
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