What is the relationship between the characteristic changes in yellow catfish (Pelteobagrus fulvidraco) farming and feed
Characteristic changes in farmed yellow catfish and their relationship with feed
The yellow catfish (Pelteobagrus fulvidraco) belongs to the order Siluriformes, family Bagridae, genus Pelteobagrus Bleeker, commonly known as ga yu, huang gu, huang qi yu, etc., and is widely distributed in rivers, lakes, ditches and other waters in China. The yellow catfish has bright body color, tender flesh and rich nutrition, and is a high-quality, valuable economic fish. It has now become one of the species that can achieve relatively good economic benefits through artificial farming. In natural waters, because the yellow catfish consumes large amounts of algae and plankton rich in carotenoids, its body color is relatively bright; under normal conditions there are black spots on the sides of the body, and the rest of the body is yellow. Under artificial farming conditions, the main problem that appears is body color change, and because of body color change the commercial value is seriously affected. Besides factors that affect body color such as water environment conditions and disease, the most important cause of body color change in yellow catfish is the major effect of feed substances on its body color. In fact, the effect of feed substances on fish body color only reflects the effect of feed substances on the overall physiological function of the fish body. Combining results from actual production and experimental research conditions, this article analyzes the main types of body color change in yellow catfish and their correlation with feed substances, hoping to provide technical reference for the formulation, production and use of compound feed for yellow catfish.1Species characteristics and body color of the genus PelteobagrusThere are 5 species in the genus Pelteobagrus, namely yellow catfish (P. fulvidraco), intermediate yellow catfish (P. intermedius), long-barbel (forktail) yellow catfish (P. eupogon), Vachelli's (river) yellow catfish (P. vachelli) and glossy yellow catfish (P. nitidus). Different species have different body shapes and body colors; some species are relatively bright in color, while others are lighter. The species mainly farmed are yellow catfish and Vachelli's yellow catfish, with other species mixed in in small amounts. Therefore, when the farmed species differ, there will be great differences in body shape and body color. Under artificial farming conditions, if one hopes to achieve the body shape and body color of yellow catfish (P. fulvidraco) in all cases, this cannot be realized; one can only achieve, according to each species' own body shape and body color, the body shape and body color that the species possesses in the natural environment.2Body color changes of yellow catfish under farming conditions and their relationship with feed(1) Yellow catfish farmed in large water bodies. Large water body farming mainly refers to yellow catfish stocked in lakes and reservoirs, without feeding compound feed; the fish feed in the natural environment, and the main foods include aquatic insects and their larvae, small shrimp, mollusks and small fish. Therefore, the fish body color is the natural body color, as shown in Figure 2, and the body color is relatively bright. (2) Yellow catfish lacking yellow pigment. In yellow catfish farmed with feed, the black body color is relatively normal, but the yellow body color is lacking; there are
relatively obvious black patches, but the skin color is lighter, and no yellow body color appears (see Figure 3). The black body color of the fish mainly depends on the number of melanocytes in the skin, their distribution density, and the distribution state of melanosomes in the melanocytes. The yellow body color mainly depends on carotenoids absorbed by the fish from the feed, such as the deposition state of lutein in the skin. These pigments are fat-soluble and are absorbed, transported and deposited along with feed fat. Therefore, when the body color of yellow catfish as shown in Figure 3 appears, it indicates that the nutritional level of the feed is insufficient, or the feed lacks carotenoids that can be absorbed and deposited; as long as corresponding adjustments are made, the body color of the yellow catfish can return to normal. (3) Yellow catfish with yellow body color. As shown in Figure 4, the black spots on the fish body basically disappear, but the yellow body color is relatively obvious. The reason for this phenomenon is the combined result of a decrease in 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. After the number and distribution density of mature melanocytes in the fish skin decrease, if the amount of lutein and carotenoids absorbed and deposited along with fat is relatively large, the fish body will show a yellow body color. Like the pigment cells of other vertebrates, new pigment cells of fish are not proliferated through cell division; instead, neural crest cells migrate to the skin, eyes and other places, differentiate into prepigment cells, and then the prepigment cells differentiate to form young melanocytes, xanthophores and other pigment cells, and the young pigment cells then develop into mature pigment cells. Taking melanocytes as an example, neural crest cells migrate to the skin, eyes and other places, differentiate into premelanocytes, and then the premelanocytes differentiate into melanoblasts, and the melanoblasts gradually grow and develop into mature melanocytes. Therefore, the formation of a mature melanocyte must go through several stages, including neural crest cell migration, differentiation of premelanocytes, development of melanoblasts, and growth of melanoblasts, during which it is regulated and controlled by various hormones and physiological factors. If a physiological error occurs at any stage during this period, it will affect the migration, differentiation, and growth and development of melanocytes, and lead to a decrease in the number and distribution density of mature melanocytes in the skin, thereby affecting the fish body. Besides being affected by factors such as farming environment and disease, the fish body is also affected by feed factors. Therefore, when this body color appears, it should be the result of feed substances seriously affecting the formation of mature melanocytes and relatively high carotenoid absorption, indicating that the feed contains substances capable of affecting the normal physiological function of the fish body, such as containing relatively large amounts of oxidized oil, containing melamine-type non-protein nitrogen, insufficient vitamins, and other reasons. The feed formula and the quality of feed raw materials should be checked, and technical measures such as eliminating harmful feed substances and ensuring sufficient vitamins should be adopted. (4) Yellow catfish whose body color is seriously affected. As shown in Figure 5, the body color of the yellow catfish shows serious changes, and both the black and yellow body colors of the fish are seriously insufficient, with the fish body showing albinism. This is the result of toxic and harmful substances in the feed causing serious damage to the physiological function of the fish body. Based on the current situation, the direct cause is that the feed raw materials contain melamine-type non-protein nitrogen, or that relatively high doses of oxidized oil were used. Any feed substance that can cause major changes in the physiological function of the fish body will cause imbalance in the overall physiological function of the fish body, and further seriously affect the normal migration, differentiation, development and maturation of pigment cells in the fish body, and cause changes in body color. This kind of fish body color change shows a strong correlation with feed quality and the feed of different feed enterprises. Only after finding and removing the substance that causes major changes in the physiological function of the fish body, and after the physiological function of the fish body gradually recovers, can the recovery of body color and the maintenance of normal body color be ensured. This should be the basic technical countermeasure for solving body color changes in fish caused by feed substances. From the analysis of the breadth and severity of the effects of feed substances on fish physiological function, at the current stage the main ones are mainly two types of feed substances: oxidized oils in feed and non-protein nitrogen such as melamine adulterated into 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 oxidized oil enters the fish body, it may continue to oxidize and produce relatively large amounts of oxygen free radicals or other free radicals. These free radicals can cause oxidation and breakage of unsaturated bonds in carotenoid molecules, causing carotenoid pigment substances to lose their pigment function and leading to degradation of fish body color. On the other hand, the effect of feed oxidized oil on the physiological function of farmed fish can seriously affect pigment cells, mainly melanocytes, so that they cannot normally differentiate, grow and mature, resulting in a significant decrease in the density of mature pigment cells, mainly melanocytes, in the skin and scales of the fish body. The result is albinism in the body color of farmed fish, or the appearance of yellow body color. As for prevention and control countermeasures, the main approach is still to adopt proactive prevention. For those farmed fish whose body color easily changes, such as yellow catfish, African catfish (Clarias gariepinus), Wuchang bream, and black carp, when formulating feed, try not to use already oxidized oil raw materials such as corn oil, rice bran oil, low-quality phospholipid oil (phospholipid powder), oxidized fish oil, as well as corn DDGS with relatively high corn oil content, corn citric acid residue, and oxidized rice bran, etc. Fats such as lard, soybean oil, rapeseed oil, and beef tallow can be selected for inclusion in the feed formula. The main hazards of melamine to farmed animals are mainly shown in the following aspects: ① It causes organic damage to the main internal organs of the fish body, producing organic pathological reactions, such as enlargement and hemorrhage of the hepatopancreas, kidney, spleen, etc. Due to damage to the main internal organ tissues, the overall physiological function of the fish body may be harmed, causing serious pathological reactions in the overall immunity and defense ability of the fish body, decreased growth rate, and increased mortality. ② Body color changes. At present, in most scaleless fish such as channel catfish, yellow catfish, and catfish, and scaled fish such as Wuchang bream and black carp, the body color shows an obvious "albino" phenomenon, and in severe cases the muscle color also changes. ③
Serious hemorrhage occurs in the digestive tract, gills, base of fin rays, epidermis, etc. ④ The production performance of farmed fish is seriously affected. For example, some enterprises have found that the farming effect of using feed containing fishmeal is not as good as that of feed not containing fishmeal, and high-protein, high-priced feed is not as good as low-protein, low-priced feed, and other difficult-to-understand strange phenomena. This is caused by adulteration of high-protein raw materials such as fishmeal. At present, the types of protein feed raw materials found to be adulterated with melamine include fishmeal, meat (bone) meal, corn gluten meal, yeast feed, monosodium glutamate protein feed, corn DDGS, rapeseed meal, cottonseed meal, microbial protein feed, etc. As for biochemical fishmeal, protein essence, biological protein essence, etc., their essence is actually made with melamine as the main raw material. If a feed enterprise finds that the use of its own feed products causes serious changes in fish body color, it must first inspect the feed raw materials used, especially protein raw materials, mainly by measuring the content of 17 amino acids and calculating that the total amount of the 17 amino acids must be greater than 90% of the crude protein mass. If it is only about 80%, it can be considered that the raw material is adulterated with melamine-type non-protein nitrogen. After removing feed raw materials containing melamine-type non-protein nitrogen from the feed formula, and using bile acid products (such as Samp; Keli Kang) and vitamin C phosphate and other products for rapid detoxification, relying on the recovery of the fish body's own physiological health, the fish body color can recover in about 1 month. (5) Effect of extruded feed on body color of yellow catfish
In groups of yellow catfish farmed with extruded feed, generally 10-20% of yellow catfish with abnormal melanin appearance will appear. Therefore, comprehensive analysis shows that during the extrusion processing of the feed, a relatively obvious effect was produced on feed substances and affected ⑵ at about 5 atmospheres. One possible reason is that vitamins are destroyed during extrusion processing, resulting in insufficient vitamins in the finished feed and affecting the body color of some fish. It is required that the use amount of vitamin premix should be increased when formulating extruded feed. As for the effects of extrusion processing on other feed substances, further study is still needed.3Protection of body color of yellow catfish and the color-enhancing effect of feed pigments on yellow catfish(1) Protection of body color of yellow catfish
Like other fish, the formation of body color in yellow catfish is a complex process. Under artificial farming conditions, changes in body color can reflect the quality and safety of the feed. It can be considered that changes in the body color of yellow catfish are in essence the result of the fish body's overall physiological function being affected to varying degrees. Therefore, during the formulation of artificial compound feed, feed processing and use, in addition to the conventional attention to feed nutritional level and completeness of nutrients, attention must also be paid to feed safety issues; the former mainly affects the normal growth rate and feed efficiency of farmed fish, while the latter will have a major impact on the maintenance of the fish body's physiological capacity and fish health. Through feed nutrition and safety, ensure the health of farmed fish. The health of farmed fish ensures growth rate and normal physiological function, protects the fish body's normal body color and normal disease resistance and stress resistance. This should be the basic concept and basic technical countermeasure for protecting the normal body color of fish. At present, the main unsafe factors affecting feed safety come from oil oxidation and adulterants in feed raw materials. The protection of the normal physiological function of melanocytes must be carried out from the protection of the overall physiological function of the fish body, such as ensuring reasonable nutrient types and nutritional levels, and eliminating the residues of toxic and harmful substances from feed in compound feed; protecting the normal yellow body color of the fish should ensure a suitable high-quality level in the compound feed, suitable pigment types in the feed, and effective pigment content. (2) Color-enhancing effect of feed pigments on yellow catfish
The body color of fish can be controlled through the selection and use of feed pigments. Through our experiments and experience summarized in actual production, adding an appropriate amount of lutein (such as Jinhuangsu and Jinjuhuang) to feed has an ideal effect on the pigmentation of yellow catfish, while astaxanthin has an unsatisfactory color-enhancing effect on yellow catfish. As shown in the figure, ensuring about 5% total fat content in the feed and adding 100 mg/T lutein gives a relatively ideal body color effect on yellow catfish after about 60 days of farming, very close to the natural body color of yellow catfish. Among these, lutein mainly comes from products extracted from marigold and corn lutein in corn gluten meal. If about 3% corn gluten meal is maintained in the compound feed, relatively ideal farming results can also be achieved. However, corn gluten meal is often found to be adulterated with melamine to increase crude protein content, so when selecting corn gluten meal, the work of quality identification and inspection must be strengthened. If the quality of corn gluten meal is difficult to guarantee, it is better not to use corn gluten meal and instead choose lutein-type pigment additives. The farming results of using 100 mg/T astaxanthin in feed show that the color-enhancing effect on the body color of yellow catfish is not ideal. In addition, the market price of astaxanthin is higher than that of lutein-type products. Therefore, astaxanthin may not be selected when enhancing the color of yellow catfish.
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Very good material, I was just needing material in this area.
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Good stuff, thanks for sharing!!!!!!!!
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I have seen a lot of this situation this year, hard to deal with, I learned something,
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Thank you, OP!!!!
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Good material, thanks for sharing! It would be even better with pictures!
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Thank you, OP, very good material. This year at a fish farm I found grass carp (adult fish) acting dizzy. After dissection I saw that the fish muscle was red! I had never seen this before, and I was very shocked. Later I suggested the owner change the feed and use feed with lower protein, and the result improved.
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Where are the photos?
It would be even better with photos!
Good material!
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Not bad, not bad, worth supporting!
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This article is by Teacher Ye Yuantu. It was included in the conference materials at the last Shihua conference, and it had pictures with it.
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Not bad, bump,,,,
relatively obvious black patches, but the skin color is lighter, and no yellow body color appears (see Figure 3). The black body color of the fish mainly depends on the number of melanocytes in the skin, their distribution density, and the distribution state of melanosomes in the melanocytes. The yellow body color mainly depends on carotenoids absorbed by the fish from the feed, such as the deposition state of lutein in the skin. These pigments are fat-soluble and are absorbed, transported and deposited along with feed fat. Therefore, when the body color of yellow catfish as shown in Figure 3 appears, it indicates that the nutritional level of the feed is insufficient, or the feed lacks carotenoids that can be absorbed and deposited; as long as corresponding adjustments are made, the body color of the yellow catfish can return to normal. (3) Yellow catfish with yellow body color. As shown in Figure 4, the black spots on the fish body basically disappear, but the yellow body color is relatively obvious. The reason for this phenomenon is the combined result of a decrease in 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. After the number and distribution density of mature melanocytes in the fish skin decrease, if the amount of lutein and carotenoids absorbed and deposited along with fat is relatively large, the fish body will show a yellow body color. Like the pigment cells of other vertebrates, new pigment cells of fish are not proliferated through cell division; instead, neural crest cells migrate to the skin, eyes and other places, differentiate into prepigment cells, and then the prepigment cells differentiate to form young melanocytes, xanthophores and other pigment cells, and the young pigment cells then develop into mature pigment cells. Taking melanocytes as an example, neural crest cells migrate to the skin, eyes and other places, differentiate into premelanocytes, and then the premelanocytes differentiate into melanoblasts, and the melanoblasts gradually grow and develop into mature melanocytes. Therefore, the formation of a mature melanocyte must go through several stages, including neural crest cell migration, differentiation of premelanocytes, development of melanoblasts, and growth of melanoblasts, during which it is regulated and controlled by various hormones and physiological factors. If a physiological error occurs at any stage during this period, it will affect the migration, differentiation, and growth and development of melanocytes, and lead to a decrease in the number and distribution density of mature melanocytes in the skin, thereby affecting the fish body. Besides being affected by factors such as farming environment and disease, the fish body is also affected by feed factors. Therefore, when this body color appears, it should be the result of feed substances seriously affecting the formation of mature melanocytes and relatively high carotenoid absorption, indicating that the feed contains substances capable of affecting the normal physiological function of the fish body, such as containing relatively large amounts of oxidized oil, containing melamine-type non-protein nitrogen, insufficient vitamins, and other reasons. The feed formula and the quality of feed raw materials should be checked, and technical measures such as eliminating harmful feed substances and ensuring sufficient vitamins should be adopted. (4) Yellow catfish whose body color is seriously affected. As shown in Figure 5, the body color of the yellow catfish shows serious changes, and both the black and yellow body colors of the fish are seriously insufficient, with the fish body showing albinism. This is the result of toxic and harmful substances in the feed causing serious damage to the physiological function of the fish body. Based on the current situation, the direct cause is that the feed raw materials contain melamine-type non-protein nitrogen, or that relatively high doses of oxidized oil were used. Any feed substance that can cause major changes in the physiological function of the fish body will cause imbalance in the overall physiological function of the fish body, and further seriously affect the normal migration, differentiation, development and maturation of pigment cells in the fish body, and cause changes in body color. This kind of fish body color change shows a strong correlation with feed quality and the feed of different feed enterprises. Only after finding and removing the substance that causes major changes in the physiological function of the fish body, and after the physiological function of the fish body gradually recovers, can the recovery of body color and the maintenance of normal body color be ensured. This should be the basic technical countermeasure for solving body color changes in fish caused by feed substances. From the analysis of the breadth and severity of the effects of feed substances on fish physiological function, at the current stage the main ones are mainly two types of feed substances: oxidized oils in feed and non-protein nitrogen such as melamine adulterated into 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 oxidized oil enters the fish body, it may continue to oxidize and produce relatively large amounts of oxygen free radicals or other free radicals. These free radicals can cause oxidation and breakage of unsaturated bonds in carotenoid molecules, causing carotenoid pigment substances to lose their pigment function and leading to degradation of fish body color. On the other hand, the effect of feed oxidized oil on the physiological function of farmed fish can seriously affect pigment cells, mainly melanocytes, so that they cannot normally differentiate, grow and mature, resulting in a significant decrease in the density of mature pigment cells, mainly melanocytes, in the skin and scales of the fish body. The result is albinism in the body color of farmed fish, or the appearance of yellow body color. As for prevention and control countermeasures, the main approach is still to adopt proactive prevention. For those farmed fish whose body color easily changes, such as yellow catfish, African catfish (Clarias gariepinus), Wuchang bream, and black carp, when formulating feed, try not to use already oxidized oil raw materials such as corn oil, rice bran oil, low-quality phospholipid oil (phospholipid powder), oxidized fish oil, as well as corn DDGS with relatively high corn oil content, corn citric acid residue, and oxidized rice bran, etc. Fats such as lard, soybean oil, rapeseed oil, and beef tallow can be selected for inclusion in the feed formula. The main hazards of melamine to farmed animals are mainly shown in the following aspects: ① It causes organic damage to the main internal organs of the fish body, producing organic pathological reactions, such as enlargement and hemorrhage of the hepatopancreas, kidney, spleen, etc. Due to damage to the main internal organ tissues, the overall physiological function of the fish body may be harmed, causing serious pathological reactions in the overall immunity and defense ability of the fish body, decreased growth rate, and increased mortality. ② Body color changes. At present, in most scaleless fish such as channel catfish, yellow catfish, and catfish, and scaled fish such as Wuchang bream and black carp, the body color shows an obvious "albino" phenomenon, and in severe cases the muscle color also changes. ③
Serious hemorrhage occurs in the digestive tract, gills, base of fin rays, epidermis, etc. ④ The production performance of farmed fish is seriously affected. For example, some enterprises have found that the farming effect of using feed containing fishmeal is not as good as that of feed not containing fishmeal, and high-protein, high-priced feed is not as good as low-protein, low-priced feed, and other difficult-to-understand strange phenomena. This is caused by adulteration of high-protein raw materials such as fishmeal. At present, the types of protein feed raw materials found to be adulterated with melamine include fishmeal, meat (bone) meal, corn gluten meal, yeast feed, monosodium glutamate protein feed, corn DDGS, rapeseed meal, cottonseed meal, microbial protein feed, etc. As for biochemical fishmeal, protein essence, biological protein essence, etc., their essence is actually made with melamine as the main raw material. If a feed enterprise finds that the use of its own feed products causes serious changes in fish body color, it must first inspect the feed raw materials used, especially protein raw materials, mainly by measuring the content of 17 amino acids and calculating that the total amount of the 17 amino acids must be greater than 90% of the crude protein mass. If it is only about 80%, it can be considered that the raw material is adulterated with melamine-type non-protein nitrogen. After removing feed raw materials containing melamine-type non-protein nitrogen from the feed formula, and using bile acid products (such as Samp; Keli Kang) and vitamin C phosphate and other products for rapid detoxification, relying on the recovery of the fish body's own physiological health, the fish body color can recover in about 1 month. (5) Effect of extruded feed on body color of yellow catfish
In groups of yellow catfish farmed with extruded feed, generally 10-20% of yellow catfish with abnormal melanin appearance will appear. Therefore, comprehensive analysis shows that during the extrusion processing of the feed, a relatively obvious effect was produced on feed substances and affected ⑵ at about 5 atmospheres. One possible reason is that vitamins are destroyed during extrusion processing, resulting in insufficient vitamins in the finished feed and affecting the body color of some fish. It is required that the use amount of vitamin premix should be increased when formulating extruded feed. As for the effects of extrusion processing on other feed substances, further study is still needed.3Protection of body color of yellow catfish and the color-enhancing effect of feed pigments on yellow catfish(1) Protection of body color of yellow catfish
Like other fish, the formation of body color in yellow catfish is a complex process. Under artificial farming conditions, changes in body color can reflect the quality and safety of the feed. It can be considered that changes in the body color of yellow catfish are in essence the result of the fish body's overall physiological function being affected to varying degrees. Therefore, during the formulation of artificial compound feed, feed processing and use, in addition to the conventional attention to feed nutritional level and completeness of nutrients, attention must also be paid to feed safety issues; the former mainly affects the normal growth rate and feed efficiency of farmed fish, while the latter will have a major impact on the maintenance of the fish body's physiological capacity and fish health. Through feed nutrition and safety, ensure the health of farmed fish. The health of farmed fish ensures growth rate and normal physiological function, protects the fish body's normal body color and normal disease resistance and stress resistance. This should be the basic concept and basic technical countermeasure for protecting the normal body color of fish. At present, the main unsafe factors affecting feed safety come from oil oxidation and adulterants in feed raw materials. The protection of the normal physiological function of melanocytes must be carried out from the protection of the overall physiological function of the fish body, such as ensuring reasonable nutrient types and nutritional levels, and eliminating the residues of toxic and harmful substances from feed in compound feed; protecting the normal yellow body color of the fish should ensure a suitable high-quality level in the compound feed, suitable pigment types in the feed, and effective pigment content. (2) Color-enhancing effect of feed pigments on yellow catfish
The body color of fish can be controlled through the selection and use of feed pigments. Through our experiments and experience summarized in actual production, adding an appropriate amount of lutein (such as Jinhuangsu and Jinjuhuang) to feed has an ideal effect on the pigmentation of yellow catfish, while astaxanthin has an unsatisfactory color-enhancing effect on yellow catfish. As shown in the figure, ensuring about 5% total fat content in the feed and adding 100 mg/T lutein gives a relatively ideal body color effect on yellow catfish after about 60 days of farming, very close to the natural body color of yellow catfish. Among these, lutein mainly comes from products extracted from marigold and corn lutein in corn gluten meal. If about 3% corn gluten meal is maintained in the compound feed, relatively ideal farming results can also be achieved. However, corn gluten meal is often found to be adulterated with melamine to increase crude protein content, so when selecting corn gluten meal, the work of quality identification and inspection must be strengthened. If the quality of corn gluten meal is difficult to guarantee, it is better not to use corn gluten meal and instead choose lutein-type pigment additives. The farming results of using 100 mg/T astaxanthin in feed show that the color-enhancing effect on the body color of yellow catfish is not ideal. In addition, the market price of astaxanthin is higher than that of lutein-type products. Therefore, astaxanthin may not be selected when enhancing the color of yellow catfish.
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Very good material, I was just needing material in this area.
--------------------------------------
Good stuff, thanks for sharing!!!!!!!!
--------------------------------------
I have seen a lot of this situation this year, hard to deal with, I learned something,
--------------------------------------
Thank you, OP!!!!
--------------------------------------
Good material, thanks for sharing! It would be even better with pictures!
--------------------------------------
Thank you, OP, very good material. This year at a fish farm I found grass carp (adult fish) acting dizzy. After dissection I saw that the fish muscle was red! I had never seen this before, and I was very shocked. Later I suggested the owner change the feed and use feed with lower protein, and the result improved.
--------------------------------------
Where are the photos?
It would be even better with photos!
Good material!
--------------------------------------
Not bad, not bad, worth supporting!
--------------------------------------
This article is by Teacher Ye Yuantu. It was included in the conference materials at the last Shihua conference, and it had pictures with it.
--------------------------------------
This article is by Teacher Ye Yuantu. It was included in the conference materials at the last Shihua conference, and it had pictures with it.No wonder the reasoning felt so clear and the explanation so thorough, so it was Teacher Ye's article.
knightydc posted on 2009-1-8 13:08
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Not bad, bump,,,,