Method for weaning of large catfish fry

Abstract

The application provides a method for large-mouth catfish fry conversion feeding, and belongs to the technical field of large-mouth catfish fry conversion feeding. The method for large-mouth catfish fry conversion feeding provided by the application feeds water worms at the beginning of the fry conversion feeding stage, then feeds pig liver for fry cultivation, and then feeds conversion feed made of pig liver and large-mouth catfish fry powder in different proportions. Through 25-36 days of step-by-step conversion feeding, the fry successfully feeds on artificial compound feed, and the fry size grows from the initial 0.5g / fish-1.7g / fish to 7g / fish-12g / fish. The large-mouth catfish fry conversion feeding is completed, and the fry conversion feeding survival rate can reach more than 89.5%. Meanwhile, the method provided by the application divides the fry into different sizes for feeding by screening the fish once every 6-9 days during the conversion feeding cultivation process, so that the self-cannibalism caused by large size difference is effectively prevented.

Description

Technical Field

[0001] This invention belongs to the field of feed conversion technology for catfish seedlings, specifically relating to a method for converting catfish seedlings to feed. Background Technology

[0002] The largemouth catfish (Catfish spp.) is a species of fish belonging to the family Siluridae in the order Siluriformes. Also known as the southern largemouth catfish, river catfish, forked-mouth catfish, and catfish barnacle, it is a large, economically important fish species found in the main streams, tributaries, and associated lakes of the Yangtze River basin in China. It prefers open water, lives a benthic lifestyle, and is carnivorous. Under natural conditions, fry primarily feed on rotifers, water fleas, tubifex worms, and other fry, while fingerlings and adults feed on bottom-dwelling fish. In artificial breeding, fry are fed a high-protein formulated feed after transitioning to a new diet. Largemouth catfish are not only large and fast-growing, but also rich in nutrients, with tender, delicious flesh and no intramuscular bones, making them highly popular with consumers. Due to their strong adaptability, good meat quality, high yield, and short breeding cycle, largemouth catfish aquaculture has developed rapidly in recent years.

[0003] In their natural environment, juvenile largemouth catfish initially feed on plankton and aquatic insect larvae. As they grow, their diet and feeding habits need to change. However, under artificial breeding conditions, successfully guiding fry from natural food to artificial feed is a significant challenge. The purpose of transitioning largemouth catfish fry to a new diet is to improve their survival rate by feeding them suitable live food and employing scientific management methods, enabling them to fully consume formulated feed at this stage. Currently, traditional methods for transitioning largemouth catfish fry to a new diet have several problems. Firstly, some farmers rely on frozen fish as a transitional feed; however, the source of frozen fish is unstable, greatly affected by seasonal, regional, and market factors, and its price fluctuates significantly, increasing the uncertainty of breeding costs. Secondly, the preservation and feeding of frozen fish is cumbersome, easily causing water pollution, which can lead to diseases and threaten the healthy growth of largemouth catfish fry. For example, during hot seasons, fresh fish are prone to spoilage if not handled properly and promptly, leading to increased levels of harmful substances such as ammonia nitrogen and nitrite in the water, significantly increasing the risk of disease in catfish fry. On the other hand, some farmers have tried using soft pellet feed, but this requires fresh preparation and feeding, consuming considerable manpower and time, making large-scale application difficult. Furthermore, when switching to floating feed, catfish are photophobic, causing the feed to float on the surface. This results in poor daytime feeding, lower daily food intake, slower growth, and difficulty achieving the desired aquaculture results. Although there are methods for transitioning catfish fry to a new diet primarily based on tubifex worms, there is no scientifically sound method, resulting in low survival rates. Furthermore, while tubifex worms, as a high-protein natural food, can promote fry growth and development, they also have some potential drawbacks: 1. Risk of pathogens and parasites: As live food, tubifex worms may carry pathogens or parasites. If not thoroughly sterilized and used directly to feed fish, it may increase the risk of disease. 2. Nutritional issues: Long-term feeding with only tubifex worms may lead to malnutrition in fish, as while tubifex worms are nutritious, their nutritional composition is relatively simple and lacks other essential nutrients for fish. 3. Water quality issues: Improper feeding or overfeeding of tubifex worms can pollute the water with their excrement and uneaten food, affecting fish health. Furthermore, if tubifex worms die after feeding, it will accelerate water deterioration. 4. Digestive issues: For some fish with poor digestive systems, feeding tubifex worms may result in the excretion of fish feces containing bloodworm skins and impurities, indicating poor absorption. Therefore, overcoming the shortcomings of existing methods for transitioning largemouth catfish fry to a new diet, achieving efficient and stable transition, improving survival rate and economic benefits, and developing a scientific and reasonable method for transitioning largemouth catfish fry to a new diet are of great practical significance and market demand. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for transitioning catfish fry to a new diet, which can significantly improve the survival rate of catfish fry after transitioning to a new diet. Through 25 to 36 days of transitioning to a new diet, the survival rate of fry after transitioning to a new diet can reach more than 89.5%.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for transitioning largemouth catfish seedlings to a new diet, comprising the following steps: first feeding the seedlings with tubifex worms to induce them to open their mouths, then feeding them with pig liver for seedling cultivation, and then sequentially feeding them transition feed 1, transition feed 2, transition feed 3 and transition feed 4.

[0007] The transition feed 1 consists of 35%–45% catfish fry powder and 55%–65% pig liver;

[0008] The transition feed 2 consists of 55%–70% catfish fry powder and 30%–45% pig liver;

[0009] The transition feed 3 consists of 55%–70% catfish fry powder, 15%–20% pig liver, and 10%–30% water;

[0010] The transition feed 4 consists of 75%–85% catfish fry powder, 5%–10% pig liver, and 5%–20% water;

[0011] The protein content of the catfish seedling powder is above 42%.

[0012] Preferably, the size of the catfish seedlings is 0.5g / fish to 1.7g / fish.

[0013] Preferably, the feeding time for tubifex worms is 6 to 9 days; the daily weight of tubifex worms should be 35% to 65% of the fish's body weight.

[0014] Preferably, the seedlings are raised by feeding them pig liver for 6 to 9 days; the weight of the pig liver fed each day is 20% to 30% of the fish's body weight.

[0015] Preferably, the feeding period for transition feed 1 is 2 to 3 days, the feeding period for transition feed 2 is 3 to 4 days, the feeding period for transition feed 3 is 3 to 5 days, and the feeding period for transition feed 4 is 5 to 6 days.

[0016] Preferably, the daily weight of feed 1, feed 2, feed 3, or feed 4 should be 10% to 15% of the fish's body weight.

[0017] Preferably, the method also includes a step of sieving the fish every 6 to 9 days.

[0018] Preferably, the fry that remain on the sieve are fed in the next step, and the fry that remain on the sieve are fed in the previous step until the fry can remain on the sieve; use an 8-day sieve when the fry body length is less than 3.3cm; use a 9-day sieve when the fry body length is more than 3.3cm but less than 4.6cm; use a 10-day sieve when the fry body length is more than 4.6cm but less than 5.9cm; use an 11-day sieve when the fry body length is more than 5.9cm but less than 7.9cm; and use a 12-day sieve when the fry body length is more than 7.9cm but less than 10cm.

[0019] Preferably, after the transition feed 4 is completed, the catfish pellet feed should be fed completely.

[0020] Preferably, the particle size of the catfish pellet feed is 1.0 mm to 2.0 mm, and the protein content of the catfish pellet feed is 42% or more.

[0021] The beneficial effects of this invention are:

[0022] The method for transitioning largemouth catfish fry provided by this invention involves first feeding them tubifex worms to induce fry initiation, then feeding them pig liver for fry cultivation, and finally preparing transition feed using different proportions of pig liver and largemouth catfish fry powder. Through a gradual transition over 25 to 36 days, the fry successfully consume the formulated feed, and their size grows from the initial 0.5g / fish to 1.7g / fish to 7g / fish to 12g / fish, completing the transition. The survival rate of the transitioned largemouth catfish fry can reach over 89.5%.

[0023] Meanwhile, the method of this invention involves screening the fish every 6 to 9 days during the transition to aquaculture, separating the fry into different sizes for rearing, effectively preventing cannibalism caused by large size differences. Detailed Implementation

[0024] This invention provides a method for transitioning largemouth catfish seedlings to a new diet, comprising the following steps: first feeding the seedlings with tubifex worms to induce them to open their mouths, then feeding them with pig liver for seedling cultivation, and then sequentially feeding them transition feed 1, transition feed 2, transition feed 3 and transition feed 4.

[0025] The transition feed 1 consists of 35%–45% catfish fry powder and 55%–65% pig liver;

[0026] The transition feed 2 consists of 55%–70% catfish fry powder and 30%–45% pig liver;

[0027] The transition feed 3 consists of 55%–70% catfish fry powder, 15%–20% pig liver, and 10%–30% water;

[0028] The transition feed 4 consists of 75%–85% catfish fry powder, 5%–10% pig liver, and 5%–20% water;

[0029] The protein content of the catfish seedling powder is above 42%.

[0030] This invention does not specifically limit the source of tubifex worms and pig liver; commercially available products commonly used in the field are acceptable. In this invention, the tubifex worms are preferably live and temporarily raised in a pond with slow-flowing water and oxygen supply; the pig liver can be frozen in a freezer for later use. In this invention, the composition of the largemouth catfish fry feed is preferably 40%–50% fish meal, 20%–22% soybean meal, 5% fish oil, 6%–8% chicken meal, 8%–10% wheat flour, 1.5% vitamin premix, 3% yeast powder, 2%–3% mineral premix, and 1.5%–2% calcium dihydrogen phosphate. The method for transferring largemouth catfish fry to a new diet can be carried out in a breeding workshop or in a cement pond within a heated greenhouse, with the water temperature maintained at 21℃–25℃. The size of the largemouth catfish fry is preferably 0.5g / fish to 1.7g / fish, more preferably 0.6g / fish to 1.5g / fish, and the fry are preferably uniform in size and free from injury or disease. After the seedlings are introduced into the pond, they should be disinfected. The disinfectant is preferably an iodine-based preparation, and the preferred specification of the iodine preparation is 0.5 g / m³. 3 .

[0031] In this invention, the optimal time for feeding tubifex worms to induce fry to open is 6 to 9 days, with 6, 7, 8, and 9 days being suitable options. The tubifex worms are preferably disinfected before feeding, preferably by soaking in salt water, with a salt water concentration of 3%. The daily weight of tubifex worms fed is preferably 35% to 65% of the fish's body weight, with 35%, 40%, 45%, 50%, 55%, 60%, and 65% being suitable options. Feeding is preferably done 4 times a day. Before each feeding, any uneaten feed from the previous feeding should be removed from the pond to ensure the freshness of the feed.

[0032] In this invention, the preferred time for feeding pig liver to raise seedlings is 6 to 9 days, and 6, 7, 8 and 9 days can be selected. When feeding pig liver, it is preferred to cut the pig liver into long strips and thin slices. The preferred weight of pig liver fed each day is 20% to 30% of the fish's body weight, and 20%, 22%, 24%, 26%, 28% and 30% of the fish's body weight can be selected. The preferred number of feedings per day is 4 times. Before each feeding, it is preferred to remove any uneaten feed from the pond.

[0033] In this invention, the transition feed 1 can be composed of 35% largemouth catfish fry powder and 65% pig liver, or 40% largemouth catfish fry powder and 60% pig liver, or 45% largemouth catfish fry powder and 55% pig liver; the transition feed 2 can be composed of 55% largemouth catfish fry powder and 45% pig liver, or 60% largemouth catfish fry powder and 40% pig liver, or 70% largemouth catfish fry powder and 30% pig liver; the transition feed 3 can be composed of 55% largemouth catfish fry powder and 65% pig liver. The feed consists of catfish fry powder, 15% pig liver, and 30% water; or 60% catfish fry powder, 20% pig liver, and 20% water; or 70% catfish fry powder, 20% pig liver, and 10% water. The transition feed 4 can consist of 75% catfish fry powder, 5% pig liver, and 20% water; or 80% catfish fry powder, 10% pig liver, and 10% water; or 85% catfish fry powder, 10% pig liver, and 5% water. In this invention, the transition feed is preferably in strip shape, with a preferred length of 3cm to 5cm, and is preferably prepared using a meat grinder.

[0034] In this invention, the feeding period for transition feed 1 is preferably 2 to 3 days, the feeding period for transition feed 2 is preferably 3 to 4 days, the feeding period for transition feed 3 is preferably 3 to 5 days, and the feeding period for transition feed 4 is preferably 5 to 6 days. The daily weight of transition feed 1, transition feed 2, transition feed 3, or transition feed 4 is preferably 10% to 15% of the fish's body weight, and can be selected as 10%, 11%, 12%, 13%, 14%, or 15% of the fish's body weight.

[0035] In the method described in this invention, a preferred method further includes a step of sieving the fish every 6 to 9 days. After sieving, the fish are separated into different ponds according to their size for feeding, which can effectively prevent cannibalism caused by large size differences. More preferably, the fry that survive the sieving are fed in the next step, and the fry that fail the sieving are fed in the previous step until the fry can remain on the sieving. The time interval for sieving the fish can be selected as 6, 7, 8, or 9 days. This invention separates the fry into different sizes for rearing, which can effectively prevent cannibalism caused by large size differences. In this invention, after feeding the fry with tubifex worms for 6 to 9 days to induce fry incubation, the fish are sieved. The fry that survive the sieving are transferred to another pond to begin the fry cultivation step by feeding them pig liver. The fry that fail the sieving are fed with tubifex worms again to induce fry incubation until the fry can remain on the sieving. The preferred time for repeating the feeding with tubifex worms to induce fry incubation is 3 to 5 days, followed by the fry cultivation step of feeding them pig liver. In this invention, after 6-9 days of fry rearing by feeding pig liver, the fish are screened. The fry that survive the screen are transferred to another pond and fed a new type of feed sequentially. The fry that fail the screen are fed the same pig liver again until they remain on the screen, at which point they are fed the new feed sequentially. Because the fry that fail the screen each time require repeated feeding, the transition period is 3-7 days longer than that of the fry that survive the screen.

[0036] In this invention, bamboo sieves are preferred for screening fish. The bamboo sieve uses its narrow, elongated openings to screen fish fry. Taking advantage of the fish fry's natural tendency to swim against the current, they "escape" through the sieve, thus separating fry by size. This results in more uniform largemouth catfish fry during the rearing process, reducing cannibalism and facilitating management and feeding. For fry less than 3.3cm in length, an 8-inch sieve is preferred; for fry between 3.3cm and 4.6cm, a 9-inch sieve is preferred; for fry between 4.6cm and 5.9cm, a 10-inch sieve is preferred; for fry between 5.9cm and 7.9cm, an 11-inch sieve is preferred; and for fry between 7.9cm and 10cm, a 12-inch sieve is preferred. This invention does not specifically limit the source of the bamboo sieves.

[0037] In this invention, after the feeding of feed 4 is completed, the catfish pellet feed is fed completely. The catfish pellet feed is preferably an extruded floating feed, the particle size of the catfish pellet feed is preferably 1.0 mm to 2.0 mm, and the protein content of the catfish pellet feed is preferably 42% or more.

[0038] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Unless otherwise specified, the following embodiments are all conventional methods.

[0040] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0041] Example 1

[0042] The method for transferring largemouth catfish fry according to this invention was tested in a breeding farm in Deyang, Sichuan. The breeding ponds in the farm were cement ponds, square in shape with sides of 5m, and the area of ​​the breeding ponds was 25m². 2 On March 17th of that year, 34,000 catfish fry were purchased and released into two cement ponds, with 17,000 fry released into each pond. The average size of the fry was 0.65g / fry. The water temperature upon release was 22℃. After the fry were released into the ponds, a 0.5g / m³ solution was used. 3 Iodine-based disinfectants;

[0043] On the day of introduction into the pond, feed the tubifex worms that have been soaked, disinfected and cleaned with 3% saline solution. The daily feeding amount is 7kg / pond, divided into four meals. Before each feeding, remove any uneaten tubifex worms from the pond to keep the feed fresh.

[0044] On March 24th, seven days after feeding, the catfish fry in the two ponds were screened for the first time using an 8-day bamboo sieve with a diameter of 60cm and a depth of 30cm. The two rearing ponds were divided into four ponds: three containing fry older than 8 days (approximately 1.1g / fish) and one containing fry younger than 8 days (approximately 0.7g / fish). The fry that passed the sieve were fed pig liver for fry rearing. The fry that passed the sieve were fed tubifex worms for another seven days before being screened again using the 8-day bamboo sieve. The results showed that all the fry passed the sieve were fry that passed the sieve and were then fed pig liver. The pig liver was frozen in the freezer before use and cut into long, thin strips before feeding. The fish were fed four times a day, with the weight of pig liver per pond being 30% of the weight of the fry per pond each day. Any uneaten feed was removed from the pond before each feeding.

[0045] On March 31st, the fish fry that passed the first screening on March 24th were screened a second time using a 9-day bamboo sieve. This screening divided the four ponds into six, with fry aged 9 days or older occupying five ponds and fry younger than 9 days occupying one pond. At this point, the size of the fry passing the screening reached 2.3g / fish. They were then fed a transitional feed, as detailed in Table 1. The catfish fry powder in Table 1 was purchased from Sichuan Tongwei Feed Co., Ltd., with a protein content of 42%, and the product name was Tongwei 141 Catfish Fry Compound Feed Powder. The size of the fry that passed the screening was 1.2g / fish. They were repeatedly fed pig liver for fry cultivation until they all passed the screening using a 9-day bamboo sieve. Then, they were fed the feed listed in Table 1.

[0046] Table 1 shows the sequential feeding of transitional feeds.

[0047]

[0048]

[0049] Note: The transition feeds in Table 1 are obtained by grinding meat into 3cm strips. The daily feeding amount of each transition feed per pond is 15% of the weight of the fry in that pond.

[0050] On the 7th day after the second screening, the fish fry that survived the second screening were fed the transition feed shown in Table 1 (i.e., after the transition feed 2 was finished). The third screening was carried out using a 10-inch screen. The fish fry that survived the second screening were fed transition feed 3 and transition feed 4. The fish fry that failed the second screening were fed transition feed 2 repeatedly until they were all fish fry that survived the second screening using a 10-inch screen. Then, they were fed transition feed 3 and transition feed 4.

[0051] By April 14th, the transition of the fry that passed through each sieve was completed. The fry that passed through each sieve, which comprised a small portion of all the fry, underwent a repeated transition process, resulting in a 7-day delay compared to the fry that passed through the sieve. By April 21st, the transition of the fry that passed through the sieve was complete. Calculations showed that the average size of all fry that had completed the transition was 7.8g / fish. They were then fed exclusively with 1.0mm diameter catfish pellet feed (the catfish pellet feed was purchased from Sichuan Tongwei Feed Co., Ltd., product name: Tongwei 141 Catfish Powder Feed). Statistics showed that the survival rate of the catfish fry after transitioning to this feed was 89.5%.

[0052] Example 2

[0053] The method for transferring largemouth catfish fry to feed according to this invention was tested in a greenhouse at a family farm in Shuangliu, Sichuan. The breeding ponds in the greenhouse were cement ponds, rectangular in shape with a length of 6m and a width of 5m, and a breeding pond area of ​​30m². 2 On March 29th of that year, 19,000 catfish fry were purchased and released into a cement pond. The average size of the fry was 1.62g / fry. The water temperature upon release was 21℃. After the fry were released, a 0.5g / m³ solution was used. 3 Iodine-based disinfectants;

[0054] On the day of introduction into the pond, feed the tubifex worms that have been soaked, disinfected and cleaned with 3% saline solution. The daily feeding amount is 12kg / pond, divided into four meals. Before each feeding, remove any uneaten tubifex worms from the pond to keep the feed fresh.

[0055] On April 5th, seven days after feeding, the catfish fry were screened for the first time to determine their density. Specifically, a 10-day bamboo sieve was used to divide the fry into three ponds, two for the fry that would be sieved over the sieve and one for the fry that would be under-sieve. After the sieving and sorting into ponds according to the sieve size, all the fry were fed pig liver. The pig liver was frozen in the freezer before use. Before feeding, it was taken out and cut into 3cm-5cm long strips. The fry were fed four times a day, with the weight of pig liver in each pond being 20% ​​of the weight of the fry in each pond. Before each feeding, any uneaten feed in the pond was removed.

[0056] Seven days later, on April 12th, the fish fry underwent a second sieving and sorting process using an 11-day-old bamboo sieve. This sorting divided the three ponds into four: three ponds for larger fry (11 days and older) and one pond for smaller fry (less than 11 days). The larger fry (11 days and older) were fed a transitional feed in sequence, as detailed in Table 2. The catfish fry powder in Table 2 was purchased from Sichuan Tongwei Feed Co., Ltd., with a protein content of 42%, and the product name was Tongwei 141 Catfish Fry Compound Feed Powder. The fry (less than 11 days) were repeatedly fed pig liver for fry cultivation until all fry passed through the 11-day-old bamboo sieve. Then, the feeding method shown in Table 2 was applied.

[0057] Table 2 shows the sequential feeding of transitional feeds.

[0058]

[0059] Note: The transition feeds in Table 2 are obtained by grinding meat into small strips. The daily feeding amount of each type of transition feed per pond is 10% of the weight of the fry in that pond.

[0060] On April 19th, the fish fry that survived the second screening were screened a third time using a 12-day bamboo sieve. This screening divided the four ponds into six: five ponds were filled with larger fry (12 days and older), and one pond was filled with smaller fry (less than 12 days). The 12-day fry that survived the screening were fed with feed 3 and feed 4. The fry that failed the screening were fed feed 2 repeatedly until they were screened again using the 12-day sieve. Then they were fed feed 3 and feed 4.

[0061] By April 30th, the transition of the fry that passed through each sieve was completed. The fry that passed through each sieve, which comprised a small portion of all the fry, underwent a repeated transition process, resulting in a 3-day delay compared to the fry that passed through the sieve. By May 3rd, the transition of the fry that passed through the sieve was complete. Calculations showed that the average size of all fry that had completed the transition was 12.6g / fish. They were then fed exclusively with 2.0mm diameter catfish pellet feed (the catfish pellet feed was purchased from Sichuan Tongwei Feed Co., Ltd., product name: Tongwei 141 catfish feed). Statistics showed that the survival rate of the catfish fry after transitioning to this feed was 95.1%.

[0062] Comparative Example 1

[0063] The difference from Example 2 is that a single type of tubifex worm was used for feeding, and the fry were screened and separated every 12 days. All other aspects were the same as in Example 2. By May 3rd, the average size of the fry was only 7.3g / fish. Statistics showed that the survival rate of the largemouth catfish fry after switching to this new diet was less than 60%.

[0064] Comparative Example 2

[0065] The difference from Example 2 is that it does not include transition feed 1; instead, it starts directly from feeding transition feed 2. Everything else is the same as in Example 2. Results showed that by May 3rd, the average size of the fry was 11.7g / fish, and the survival rate of the largemouth catfish fry after transitioning to this feed was 78%.

[0066] Comparative Example 3

[0067] The difference from Example 2 lies in the proportions of transition feed 1 through transition feed 4. Transition feed 1 consists of 30% largemouth catfish fry powder and 70% pig liver; transition feed 2 consists of 40% largemouth catfish fry powder and 60% pig liver; transition feed 3 consists of 60% largemouth catfish fry powder and 40% pig liver; and transition feed 4 consists of 90% largemouth catfish fry powder, 5% pig liver, and 5% water. All other components remain the same as in Example 2. Results showed that by May 3rd, the average size of the fry was 11.3g / fish, and the survival rate of the largemouth catfish fry after transition feeding was 85%.

[0068] Example 3

[0069] The difference from Example 2 is that the feed was introduced sequentially as shown in Table 3, while the rest was the same as in Example 2.

[0070] Table 3 shows the sequential feeding of transitional feeds.

[0071]

[0072] Note: The transition feeds in Table 3 are obtained by grinding meat into 4cm strips. The daily feeding amount of each transition feed per pond is 15% of the weight of the fry in that pond.

[0073] The results showed that by April 26, the fry that passed through each sieve had completed their transition to a new diet. The fry that passed through each sieve, which comprised a small portion of all the fry, underwent a repeated transition process, resulting in a 4-day delay compared to the fry that passed through the sieve. By April 30, the transition to a new diet for the fry that passed through the sieve was complete. Calculations showed that the average size of all fry that had completed the transition was 13.0g / fish. They were then fed exclusively with 2.0mm pelleted feed for largemouth catfish (the largemouth catfish pelleted feed was purchased from Sichuan Tongwei Feed Co., Ltd., product name: Tongwei 141 Largemouth Catfish Compound Feed). Statistics showed that the survival rate of the largemouth catfish fry after transitioning to this new diet was 93.5%.

[0074] Example 4

[0075] The difference from Example 2 is that the transition feed was fed sequentially as shown in Table 4; all other aspects are the same as in Example 2.

[0076] Table 4 shows the sequential feeding of transitional feeds.

[0077]

[0078] Note: The transition feeds in Table 4 are obtained by grinding meat into 4cm strips. The daily feeding amount of each transition feed per pond is 13% of the weight of the fry in that pond.

[0079] The results showed that by April 25th, the fry that passed through each sieve had completed their transition to a new diet. The fry that passed through each sieve, representing a small portion of the total fry, underwent a repeated transition process, resulting in a 5-day delay compared to the fry that passed through the sieve. By April 30th, the transition to a new diet for the fry that passed through the sieve was complete. Calculations showed that the average size of all fry that had completed the transition was 12.4g / fish. They were then fed exclusively with 2.0mm diameter catfish pellet feed (purchased from Sichuan Tongwei Feed Co., Ltd., product name: Tongwei 141 Catfish Powder Feed). Statistics showed that the survival rate of the catfish fry after transitioning to this new diet was 94.8%.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for converting catfish fry to a new diet, characterized in that, The process includes the following steps: first, feed the seedlings with tubifex worms to induce larval development, then feed them with pig liver for seedling cultivation, and then feed them with transition feed 1, transition feed 2, transition feed 3 and transition feed 4 in sequence. The transition feed 1 consists of 35%–45% catfish fry powder and 55%–65% pig liver; The transition feed 2 consists of 55%–70% catfish fry powder and 30%–45% pig liver; The transition feed 3 consists of 55%–70% catfish fry powder, 15%–20% pig liver, and 10%–30% water; The transition feed 4 consists of 75%–85% catfish fry powder, 5%–10% pig liver, and 5%–20% water; The protein content of the catfish seedling powder is above 42%; The size of the largemouth catfish seedlings is 0.5g / fish to 1.7g / fish; Feeding tubifex worms allows the fry to begin eating in 6 to 9 days; the daily weight of tubifex worms should be 35% to 65% of the fish's body weight. The seedlings are raised by feeding them pig liver for 6 to 9 days; the weight of the pig liver fed to them each day is 20% to 30% of the fish's body weight. It also includes the step of sieving the fish every 6 to 9 days; For fry that remain on the sieve, proceed to the next feeding step. For fry that remain on the sieve, repeat the previous feeding step until the fry can stay on the sieve. Use an 8-day sieve for fry with a body length of less than 3.3cm; use a 9-day sieve for fry with a body length of 3.3cm or more but less than 4.6cm; use a 10-day sieve for fry with a body length of 4.6cm or more but less than 5.9cm; use an 11-day sieve for fry with a body length of 5.9cm or more but less than 7.9cm; and use a 12-day sieve for fry with a body length of 7.9cm or more but less than 10cm. Feeding transition feed 1 for 2 to 3 days, transition feed 2 for 3 to 4 days, transition feed 3 for 3 to 5 days, and transition feed 4 for 5 to 6 days; Feed the fish with transition feed 1, transition feed 2, transition feed 3, or transition feed 4 daily at a weight of 10% to 15% of the fish's body weight.

2. The method according to claim 1, characterized in that, After the transition feed 4 is completed, feed the catfish pelleted compound feed completely.

3. The method according to claim 2, characterized in that, The particle size of the catfish pellet feed is 1.0 mm to 2.0 mm, and the protein content of the catfish pellet feed is above 42%.

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