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The experimental fish test fish was the Songpu mirror carp species cultivated at the Songpu Experimental Station of the Heilongjiang Fisheries Research Institute in the same year. After being sterilized with a volume fraction of 3% NaCl solution for a week, the fish was selected for robustness, neat specifications and body weight (5.51±0.05). ) The 756 tails of Matsuura oyster juvenile fish were used for the test. The feed was imported from Peru as steamed fish meal and soybean meal as the main protein source, and imported high-quality fish oil as the fat source. Based on the basic nutritional requirements of quail, 4 kinds of fat content were formulated in the basic feed by adjusting the ratio of fish oil and α-cellulose. For the mass fraction, the same below) were iso-nitrogen feeds (average of 43.22% for crude protein) at 5.55%, 8.43%, 11.78%, and 15.60% (measured). The fat content of the test feed should be strictly controlled using a crude fat analyzer. After the feed ingredients are crushed, they shall be sieved through a 40-mesh sieve, weighed and mixed with a drum mixer for 10 minutes. After mixing thoroughly, the mixture shall be processed into pellet feeds of 1.0 mm in diameter and 2.0 mm in diameter by two small granulators and dried naturally. Store in a freezer (-20°C) for use.
Effects of dietary fat levels on the immune parameters of Matsuura mirror borer at different temperatures: At 16°C, the fat content of each feed had no significant effect on the activity of LYZ and serum immune parameters (P>0.05); at 23°C, 8% The LYZ activity in the hepatopancreas of the fat group was significantly higher than that in the 15% fat group (P<0.05). At 30°C, the LYZ activity in hepatopancreas decreased with the increase of feed fat, and the LYZ activity in the hepatopancreas of the 5% fat group was the highest. And significantly higher than 8% and 15% fat group (P <0.05), serum IgM content increased with the increase of dietary fat levels, 5% fat group was significantly lower than 11% fat group (P <0.05); There was no significant difference in various indicators of feed fat levels (P>0.05); the interaction of temperature and feed fat levels only had a significant effect on hepatopancreas LYZ activity (P<0.05). At 16°C, SOD and CAT in the liver pancreas of Songpu mirror decreased with the increase of feed fat level, while MDA content in hepatopancreas increased with the increase of feed fat level, of which 5% and 8% of fat group liver The activities of SOD and CAT in the pancreas were significantly higher than those in the 11% and 15% fat groups (P<0.05). The MDA content in the hepatopancreas of the 8% fat group was significantly lower than that in the 15% fat group (P<0.05). The MDA content in the spleen was associated with The level of feed fat decreased and the 15% fat group was significantly lower than the 5% and 8% fat groups (P<0.05). At 23°C, hepatic pancreas SOD activity was significantly higher in 8% and 11% fat groups than in 5% and 15% fat groups (P<0.05). Spleen SOD activity in 8% and 15% fat groups were significantly higher than 5% in fat. Group (P<0.05); Hepatic pancreas and spleen CAT activity were not significantly different in each fat group (P>0.05); hepatic pancreas and spleen MDA content increased significantly with increasing feed fat levels (P<0.05). ). At 30°C, there was no significant difference in antioxidant indexes among the fat groups (P>0.05). The interaction between temperature and feed fat had no significant effect on the SOD and CAT activities of the spleen (P>0.05), but had a significant effect on other indicators (P<0.05).
Effects of dietary fat levels on the antioxidant capacity of the liver and pancreas and spleen of Matsuura Mirror: The survival of animal cells requires a proper balance between oxidation and antioxidants. MDA is considered to be the main decomposition product of lipid peroxidation. The level of its content can not only indirectly reflect the content of reactive oxygen radicals, but also reflect the intensity or rate of lipid peroxidation of tissue cells. There is an effective antioxidant defense system in fish to remove oxygen free radicals and their metabolites. This antioxidant system mainly includes antioxidant enzymes such as SOD and CAT. The determination of the activity of these two enzymes is often used to assess the dynamic changes in free radical reactions in the body and tissue damage. There have been some reports on the effects of feed fat levels on fish antioxidative capacity. Wang Chaoming et al. showed that SOD activity of hepatopancreas of carps increased first and then decreased with the increase of feed fat level, while MDA content decreased first and then rose. Gao Shi and Lin Shimei et al. showed that the CAT activity and MDA content of tilapia hepatopancreas increased with the increase of dietary fat levels, and the SOD activity decreased significantly in the 8.5% fat group. In this experiment, the MDA content in the hepatopancreas of the mirror carp increased with the increase of fat content at each temperature, especially at 23°C. At this temperature, the MDA content in hepatopancreas of 11% fat group was higher than 5 The % and 8% fat groups more than doubled, suggesting that fatty acids in the hepatopancreas of the mirror carp began to be over-oxidized and that the peroxide products increased. At 16°C, SOD and CAT activities both decreased with increasing dietary fat levels, suggesting that high feed fat levels at 16°C can cause a decrease in antioxidant capacity of S. ruthenica, and at 23°C, 11% of the hepatic pancreas SOD and The activity of CAT was significantly higher than that of other groups, and the MDA content in the feed fat level increased significantly, which caused the oxidative stress in the fish body to begin. At 30 °C, the dietary fat level had no significant effect on the antioxidant capacity of æ¾P. , It may be that the temperature in the Matsuura mirror quinone metabolism accelerated, and the antioxidant enzyme activity increased, thereby weakening the impact of feed fat levels.
Comprehensive analysis of the effect of feed fat level on the immunity and antioxidation capacity of juvenile fish from Songpu Mirroring, from the point of view of fish immunity, the feed fat content of juvenile fish from Songpu mirror was not more than 8% and 11% at 16°C and 23°C, respectively. Therefore, we should strictly control the fat content of feedstuffs to about 10% during the feeding of juvenile fish in Songpu.
Rapidly Breathing Matsuura Mirror Carp by Controlling Fat Content in Feed
In this study, the authors used different feeds at different water temperatures to feed the mirror carp, and determined the immune and antioxidant capacity of young juvenile fish of the Matsuura mirror carp by observing their effects on immune performance. Fat in the feed, especially essential fatty acids Is an important regulator of immune responses in aquatic animals, but when the fat level in the feed exceeds the demand, it will lead to increased fat deposition in the fish, which will affect the immune function of the fish. In severe cases, it will even cause a lot of fat in the fish liver cells. Accumulation leads to decreased liver function or even failure. If the fat content in the body increases, the oxidation reaction of the fish will increase, but the fish has an antioxidant mechanism, can resist oxidative damage and maintain health, in order to provide research for optimum fat requirements of juvenile fish of the common puffer at different water temperature conditions. reference.