Why can't the body color of yellow croaker turn yellow in running water culture?

Whether it is pond running water aquaculture or river aquaculture Pelteobagrus fulvidraco body color can not turn yellow after feeding the color conversion material, I do not know if you encounter the same problem, guidance, thank you! Is it because Pelteobagrus fulvidraco consumes a lot of energy in running water, doesn't add enough fat to its feed, and doesn't have a good pigmentation? Pelteobagrus fulvidraco (Pelteobagrus fulvidraco), which belongs to Siluriformes, Bagridae and Pelteobagrus Bleeker, is widely distributed in rivers, lakes and ditches in China. Pelteobagrus fulvidraco (Pelteobagrus fulvidraco) is a kind of high quality and valuable economic fish with bright color, fresh meat and rich nutrition. at present, it has become one of the species with better economic benefits in artificial culture. Pelteobagrus fulvidraco in natural water, due to the intake of a large number of carotenoid-rich algae and plankton, the body color is bright, normally there are black spots on the side of the body, and the rest is yellow. Under the condition of artificial culture, the main problem is the change of body color, which seriously affects the value of goods. The most important reason for the change of body color of Pelteobagrus fulvidraco is that the feed material has a great influence on its body color besides the environmental conditions of water area, disease and other factors that affect the body color. The effect of feed substance on fish body color only reflects the effect of feed substance on the whole physiological function of fish body. Based on the results of actual production and experimental research, this paper analyzed the main types of body color changes of Pelteobagrus fulvidraco and its correlation with feed substances, hoping to provide technical reference for the preparation, production and use of formula feed for Pelteobagrus fulvidraco. 1. Species characteristics and body color of Pelteobagrus. The characteristics of each fish are Pelteobagrus fulvidraco (P.intermedius), Pelteobagrus fulvidraco (P.eupogon), Pelteobagrus fulvidraco (P.eupogon), Pelteobagrus fulvidraco (P.vachelli) and Pelteobagrus fulvidraco (P.nitidus). Different species have different body shapes and colors, some of which are brighter and some are lighter. The farmed species are mainly Pelteobagrus fulvidraco and Pelteobagrus fulvidraco, and a small amount of other species are mixed among them. Therefore, the body shape and color of fish vary greatly with different types of artificial culture. Under the condition of artificial culture, it is impossible to achieve the body shape and color of Pelteobagrus fulvidraco (p.fulvldraco). It can only be changed according to the body type and color of different species in the natural environment. 2. The change of body color of Pelteobagrus fulvidraco and its relationship with feed under the condition of culture. (1) Pelteobagrus fulvidraco cultured on large water surface is mainly Pelteobagrus fulvidraco cultured in lakes and reservoirs, not fed with compound feed, and the fish is fed in the natural environment. the main foods include aquatic insects and their larvae, shrimp, molluscs and small fish. Therefore, the fish body color is a natural body color, as shown in figure 2, the body color is more bright. (2) the black body color of Pelteobagrus fulvidraco cultured in feed is relatively normal, but lack of yellow body color; there are more obvious black plaques, but the skin color is lighter, there is no yellow body color (see figure 3). Fish body color black body color mainly depends on the number and distribution density of melanocytes in the skin, as well as the distribution of melanosomes in melanocytes. The yellow body color mainly depends on the carotenoids absorbed by the fish from the feed, such as the deposition of lutein in the skin, this kind of pigment is fat-soluble and is accompanied by the absorption, transport and deposition of feed fat. Therefore, when the body color of Pelteobagrus fulvidraco in figure 3 appears, it indicates that the nutrition level of the feed is not enough, or there is a lack of carotenoids that can be absorbed and deposited in the feed, and the body color of Pelteobagrus fulvidraco can be restored to normal as long as the corresponding adjustment is made. (3) the black spot of yellow body color Pelteobagrus fulvidraco basically disappeared, but the yellow body color was more obvious. the reason for this phenomenon is the decrease of the number and distribution density of mature melanocytes in the skin and the deposition of yellow pigments such as lutein and carotenoids in the skin and muscle. When the number and distribution density of mature melanocytes in fish skin decrease, if there is a large amount of lutein and carotenoids accompanied by fat absorption and deposition, the fish will appear yellow body color. Like the pigment cells of other vertebrates, the new pigment cells in fish do not proliferate through cell division, but migrate from the nerve crest cells to the skin and eyes and differentiate into prepigment cells. then the prepigment cells differentiate into young melanocytes, yellow pigment cells and other pigment cells, and the young pigment cells develop into mature pigment cells. Take melanocytes as an example, neural crest cells migrate to the skin and eyes, differentiate into premelanocytes, and then differentiate from premelanocytes into melanocytes, which gradually grow and develop into mature melanocytes. Therefore, the formation of a mature melanocyte goes through several stages, such as the migration of nerve crest cells, the differentiation of premelanocytes, the development of melanoblasts, the growth of melanocytes and so on. during this period, it is regulated and controlled by a variety of hormones and physiological factors. if there are physiological errors in any link during the period, it will affect the migration, differentiation, growth and development of melanocytes. It also leads to the decrease of the number and distribution density of mature melanocytes in the skin, which affects the fish not only by culture environment, disease and other factors, but also by feed factors. Therefore, when this body color appears, it should be the result that the feed material seriously affects the formation of mature melanocytes and the absorption of carotenoids, indicating that the feed contains substances that can affect the normal physiological function of fish. For example, it contains more oxidized oil, melamine non-protein nitrogen, vitamin deficiency and so on. The quality of feed formula and feed raw materials should be checked, and technical measures such as removing harmful feed substances and ensuring adequate vitamins should be taken. (4) the body color of Pelteobagrus fulvidraco was seriously affected, as shown in figure 5, the body color of Pelteobagrus fulvidraco changed seriously, the black and yellow body colors were seriously insufficient, and the fish showed albinism. This is the result of serious damage to the physiological function of fish caused by the presence of toxic and harmful substances in feed. According to the analysis of the current situation, the direct reason is that the feed raw materials contain melamine non-protein nitrogen, or use a higher dose of oxidized oil. Any feed substance that can cause significant changes in the physiological function of the fish will cause the imbalance of the whole physiological function of the fish, and then seriously affect the normal migration, differentiation, development and maturation of the pigment cells of the fish, and cause the change of the body color of the fish. this kind of fish body color change shows a strong correlation with feed quality and feed from different feed enterprises. Only by finding and removing this substance which causes significant changes in the physiological function of the fish, the gradual recovery of the physiological function of the fish can ensure the recovery of the body color and the maintenance of the normal body color. This should be the basic technical countermeasure for us to solve the changes of fish body color caused by feed substances. According to the analysis of the universality and severity of the effects of feed substances on the physiological function of fish, at present, the main feed substances are oxidized oil in feed and non-protein nitrogen such as melamine in feed raw materials, followed by vitamins and minerals, especially some trace elements. The effect of feed oxidized oil on fish body color includes two aspects. First, after the oxidized oil enters the fish, it may continue to oxidize and produce more oxygen free radicals or other free radicals, which can lead to the oxidation and breaking of the unsaturated bonds in carotenoid molecules. Carotenoid pigments lose pigment function and lead to body color degradation. On the other hand, the effect of feed oxidized oil on the physiological function of cultured fish can seriously affect the abnormal differentiation, growth and maturation of pigment cells, mainly melanocytes, which lead to a significant decrease in the density of mature pigment cells, mainly melanocytes, in fish skin and scales. as a result, the body color of farmed fish is albino or yellow. As for the prevention and control measures, we should mainly take active prevention measures. For those farmed fish whose body color is easy to change, such as Pelteobagrus fulvidraco, Clarias fulvidraco, Wuchang fish, herring and so on, try not to use oxidized oily materials such as corn oil, rice bran oil, inferior phospholipid oil (phospholipid powder), oxidized fish oil, corn DDGS and corn citric acid dregs with high corn oil. And oxidized rice bran and so on. You can choose lard, soybean oil, vegetable oil, butter and other fats into the feed formula. The main harm of melamine to farmed animals is mainly shown in the following aspects: ① causes organic damage to the main internal organs of fish, resulting in organic pathological reactions, such as hepatopancreas, kidney, spleen, swelling, bleeding and so on. Due to the injury of the main organs and tissues of the viscera, it may lead to the injury of the overall physiological function of the fish, resulting in serious pathological reactions in the overall immunity and defense ability of the fish, the decrease of growth rate, the increase of mortality and so on. The body color of ② has changed. At present, in most scaleless fish, such as channel catfish, yellow catfish, moustache catfish, scaly fish such as Wuchang fish, herring, etc., there is a significant "whitening" phenomenon in body color, and serious muscle color will also change. Serious bleeding occurred in the digestive tract, Gill, base of fin and epidermis of ③. The production performance of ④ farmed fish has been seriously affected, for example, in some enterprises, the effect of using fishmeal feed is not as good as that without fishmeal feed, and the effect of high protein and high price feed is not as good as low protein, low price feed and other strange phenomena that are difficult to understand, this is due to the adulteration of high protein raw materials such as fishmeal. At present, it has been found that the raw materials of protein feed mixed with melamine include fish meal, meat (bone) meal, corn gluten meal, yeast feed, monosodium glutamate protein feed, corn DDGS, rapeseed meal, cottonseed meal, bacterial protein feed and so on. If feed enterprises find serious changes in fish body color when using their own feed products, they must first check the feed raw materials used, especially protein raw materials, mainly by determining the content of 17 kinds of amino acids, it is calculated that the total amount of 17 kinds of amino acids must be greater than 90% of their crude protein mass, and if only about 80%, it can be considered that the raw materials are mixed with melamine non-protein nitrogen. After removing the raw materials of non-protein nitrogen feed containing melamine in the feed formula, and after rapid detoxification with products such as bile acids (such as Sampricam) and vitamin C phosphate, depending on the recovery of fish's autogenic physiological health, the body color of the fish can be restored in about a month. Effect of ⑸ expanded feed on body color of Pelteobagrus fulvidraco Pelteobagrus fulvidraco cultured with expanded feed, there are generally 10-20% abnormal melanin in Pelteobagrus fulvidraco population. Therefore, according to the comprehensive analysis, one possible reason is that vitamins are destroyed during the puffing process, which leads to the deficiency of vitamins in the finished feed and affects the body color of some fish. therefore, according to the comprehensive analysis, because of the obvious influence on feed substances and ⑵ at about 5 atmospheric pressure, one possible reason is that the use of vitamin premix should be increased in the preparation of extruded feed. As for the effect of puffing on other feed substances, it remains to be studied. 3. Body color protection of Pelteobagrus fulvidraco and hyperchromic effect of feed pigment on Pelteobagrus fulvidraco (1) Pelteobagrus fulvidraco body color protection Pelteobagrus fulvidraco like other fish, its body color formation is a complex process. Under the condition of artificial culture, the quality and safety of feed can be reflected by the change of body color. It can be considered that the change of body color of Pelteobagrus fulvidraco is the result of different degrees of influence on the whole physiological function of fish. Therefore, in the process of formulation, processing and use of artificial compound feed, attention should be paid to feed safety in addition to routine attention to feed nutrition level and nutrient integrity; the former mainly affects the normal growth rate and feed efficiency of cultured fish, while the latter will have a significant impact on the maintenance of tongue root skills and fish health of cultured fish. The health of farmed fish can be ensured through feed nutrition and safety. The health of farmed fish ensures the growth rate and normal physiological function, and protects the normal body color and normal resistance to disease and stress, which should be the basic concept and basic technical countermeasures to protect the normal body color of fish. At present, the main unsafe factors affecting feed safety come from the oxidation of oil and the adulteration of feed raw materials. The protection of the normal physiological function of du Yu melanocytes must be carried out from the protection of the whole physiological function of the fish body, such as ensuring the reasonable types and levels of nutrients and eliminating the residues of toxic and harmful substances in the formula feed; to protect the normal yellow body color of fish should ensure the appropriate high quality level in formula feed, appropriate pigment species and effective content of pigment in compound feed. The hyperchromic effect of ⑵ feed pigment on Pelteobagrus fulvidraco body color can be controlled by the selection and utilization of feed pigment. Through our experiments and practical production experience, adding appropriate amount of lutein (such as gold and chrysanthemum yellow) to the feed has an ideal effect on the coloration of Pelteobagrus fulvidraco, but astaxanthin is not ideal for Pelteobagrus fulvidraco. As shown in the figure, ensuring about 5% of the total fat in the feed and adding the amount of lutein in 100mg/T has an ideal effect on the body color of Pelteobagrus fulvidraco cultured for about 60 days, which is very close to the natural body color of Pelteobagrus fulvidraco. Lutein mainly comes from the products extracted from marigold and zeaxanthin from corn gluten meal. If you keep about 3% corn gluten meal in the formula feed, you can also achieve a more ideal breeding effect. However, melamine is often found in corn gluten meal to increase the content of crude protein, so it is necessary to strengthen the quality identification and inspection when selecting corn gluten. If the quality of corn gluten meal is difficult to guarantee, we would rather not use corn gluten meal and choose the additive of lutein pigment. When 100mg/T astaxanthin was used in the feed, the hyperchromic effect on the body color of Pelteobagrus fulvidraco was not ideal, and the market price of astaxanthin was higher than that of lutein products, so astaxanthin could not be used in the hyperchromism of Pelteobagrus fulvidraco. Turn off the water or turn it off for a try Have the fish in other ponds changed?-- I really haven't found this phenomenon before-- is it a common phenomenon or an individual? do you want to turn it or not? Give it a try-- non-aquaculture customers have turned yellow. Running water farming has not changed color, fat must be enough, the quality of raw materials can also be guaranteed. It's really a strange phenomenon-solution loss? Pond culture would be better.