Domestication bait and domestication method for mandarin fish fry

Abstract

The invention relates to the technical field of fry domestication, in particular to domestication bait and domestication method for mandarin fish fries. According to the specific technical scheme, the domestication bait for the mandarin fish fries comprises live crucian carp fries and silver carp fries, half-dead crucian carp fries and half-dead silver carp fries, mandarin fish powder, a mixture of the dead crucian carp fries and the dead silver carp fries and mandarin fish feed 0 #; a phagostimulant is added into the powder, and the phagostimulant is one of squid paste, betaine and hermetia illucens pulp. According to the three phagostimulants disclosed by the invention, the feeding domestication efficiency can be improved, the squid paste has the most obvious effect in the aspect of promoting the early growth performance and is excellent in related physiological metabolism indexes, and the betaine relieves the liver metabolism burden in the mandarin fish domestication process.

Description

Technical Field

[0001] The present invention relates to the technical field of fry domestication, and particularly relates to a domestication bait and a domestication method for mandarin fish fry. Background Art

[0002] The mandarin fish (Siniperca chuatsi), also known as osmanthus fish and seasonal flower fish, belongs to the order Perciformes, subfamily Sinipercinae, and genus Siniperca. Its meat is tender with few spines, rich in nutrition and delicious in taste, making it a precious freshwater fish. Currently, the development of artificial feed farming for mandarin fish has become a new trend in the industry in recent years. Culturing mandarin fish with artificial feed can not only significantly reduce the breeding cost and improve the breeding efficiency, but also provide an effective way to solve the problem of mandarin fish diseases. However, there are great difficulties in fry domestication in feed mandarin fish farming. The main reason is that artificial compound feed directly leads to the inactive feeding or refusal of food by mandarin fish. The feed stays in water for too long, which not only causes waste of feed, but also pollutes the breeding water body. The low food intake of mandarin fish results in insufficient energy intake, which directly affects a series of problems such as domestication rate and survival rate in the early fry domestication stage.

[0003] Therefore, it is particularly important to add attractants in the mandarin fish fry domestication stage to promote the feeding of mandarin fish, improve the domestication rate and survival rate, and reduce feed waste and pollution. Taking mandarin fish fry as the object, using squid paste, betaine and black soldier fly larva slurry as attractants, this invention studies their effects on the growth, physiological and biochemical indexes and domestication rate of juvenile mandarin fish, evaluates their attracting effects, provides a theoretical basis for the early fry domestication technology and feed formula of mandarin fish, with a view to applying it to production practice and promoting the development of the whole-process compound feed farming of mandarin fish and the mandarin fish industry. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a domestication bait and a domestication method for mandarin fish fry.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0006] The present invention discloses a domestication bait for mandarin fish fry, which includes live crucian carp fry and silver carp fry, semi-dead crucian carp fry and semi-dead silver carp fry, a mixture of mandarin fish powder, dead crucian carp fry and dead silver carp fry, and No. 0 mandarin fish feed; an attractant is added to the powder, and the attractant is one of squid paste, betaine and black soldier fly larva slurry.

[0007] Preferably, the addition amount of the attractant is 1.5% of the powder.

[0008] Correspondingly, a method for domesticating mandarin fish fry is to feed the above-mentioned domesticated bait for mandarin fish fry twice a day, with a daily feeding rate of 4%-5%. Feed until full each time. Before feeding, turn off the microporous aeration equipment and turn on the circulating water flow to impact the water surface to stimulate the fish group to gather.

[0009] Preferably, during the domestication process, live crucian carp fry and silver carp fry, half-dead crucian carp fry and half-dead silver carp fry, a mixture of mandarin fish powder, dead crucian carp fry and dead silver carp fry, and No. 0 mandarin fish feed are used in sequence for feeding.

[0010] Preferably, feed with live crucian carp fry and silver carp fry for the first 2 days, then feed with half-dead crucian carp fry and half-dead silver carp fry for 3 days, then use mandarin fish powder mixed with dead crucian carp fry and half-dead silver carp fry for feeding and domestication for 3 days, and then switch to No. 0 mandarin fish feed. Soak the feed in water before feeding. The domestication test period is 8 days in total.

[0011] The present invention has the following beneficial effects:

[0012] The three kinds of attractants disclosed in the present invention can all improve the domestication efficiency. Among them, squid paste has the most obvious effect on promoting early growth performance, and the related physiological and metabolic indexes are excellent, while betaine can reduce the liver metabolic burden during the domestication of mandarin fish. Detailed implementation manners

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0014] Unless otherwise specified, the technical means used in the implementation examples are conventional means well-known to those skilled in the art.

[0015] The present invention discloses a domesticated bait for mandarin fish fry, which includes live crucian carp fry and silver carp fry, half-dead crucian carp fry and half-dead silver carp fry, a mixture of mandarin fish powder, dead crucian carp fry and dead silver carp fry, and No. 0 mandarin fish feed; an attractant is added to the powder, and the attractant is one of squid paste, betaine and black soldier fly larvae slurry. The addition amount of the attractant is 1.5% of the powder.

[0016] The present invention discloses a method for domesticating mandarin fish fry, which feeds the above-mentioned domesticated bait for mandarin fish fry twice a day, with a daily feeding rate of 4%-5%. Feed until full each time. Before feeding, turn off the microporous aeration equipment and turn on the circulating water flow to impact the water surface to stimulate the fish group to gather, and feed slowly in small amounts and multiple times.

[0017] Furthermore, during the domestication process, live crucian carp fry and silver carp fry, half-dead crucian carp fry and half-dead silver carp fry, a mixture of mandarin fish powder, dead crucian carp fry and dead silver carp fry, and mandarin fish feed No. 0 were used for feeding in sequence. Specifically: in the first 2 days, live crucian carp fry and silver carp fry were used for feeding, then half-dead crucian carp fry and half-dead silver carp fry were fed for 3 days, and then mandarin fish powder was mixed with dead crucian carp fry and half-dead silver carp fry for feeding. After 3 days of domestication, it was switched to mandarin fish feed No. 0. The feed was soaked in water before feeding. The domestication test period was 8 days in total.

[0018] The present invention will be further described below in conjunction with specific embodiments.

[0019] Example 1

[0020] 1. Experimental animals and feed

[0021] Mandarin fish fry, crucian carp, and silver carp bait fish were bred, hatched, and cultivated by Jingzhou Xinchuang Fisheries Co., Ltd. During the domestication process of juvenile fish, powder feed and expanded feed were purchased from Guangdong Yuequn Biotechnology Co., Ltd. The attractants squid paste and betaine were purchased commercially, and black soldier fly larvae slurry was purchased from Guangzhou Feixite Biotechnology Co., Ltd.

[0022] During the domestication process, attractants were added at 1.5% of the powder feed quality. The attractants were mixed with water and then further mixed with the powder feed to form a paste for feeding.

[0023] 2. Experimental design and feeding management

[0024] 2.1 Domestication of mandarin fish juvenile feed

[0025] 40,000 mandarin fish juveniles with an average body length of 4 - 6 cm were randomly and evenly placed into 8 net cages with a size of 4×2×2 m and a pond water depth of 2.5 m. Each net cage contained 5,000 fish. Oxygenation machines were equipped around the net cages, and a bottom microporous oxygenation and circulating water system was equipped inside. One control group and three experimental groups were set up, with an average of two replicates for each experimental group. The control group did not use any attractants throughout the process, and other domestication processes were the same as those of the experimental groups.

[0026] During the domestication process of the experimental groups, live crucian carp fry + silver carp fry, half-dead crucian carp fry + half-dead silver carp fry, mandarin fish powder + dead crucian carp fry + dead silver carp fry, and mandarin fish feed No. 0 were used for feeding in sequence. Specifically: in the first 2 days of the experimental groups, live crucian carp fry + silver carp fry were used for feeding, then half-dead crucian carp fry + half-dead silver carp fry were fed for 3 days, and then mandarin fish powder was mixed with dead crucian carp fry + half-dead silver carp fry for feeding. After 3 days of domestication, it was switched to mandarin fish No. 0 feed. The feed was soaked in water before feeding. The domestication test period was 8 days in total.

[0027] Three experimental groups were respectively added with attractants squid paste, betaine and black soldier fly larvae slurry, and the addition ratio was 1.5% of the bait quality. After dissolving in water, they were fully mixed with the bait. During the feeding period, feeding should be carried out regularly, at a fixed point, in a fixed quantity and with a fixed signal, twice a day (at 5:30 in the morning and 18:30 in the evening), and the daily feeding rate was 4%-5%. Each time, feed until the fish were full. Before feeding, turn off the microporous aeration equipment, turn on the circulating water to impact the water surface to stimulate the fish to gather, and feed slowly in small amounts and multiple times. During the experiment, the temperature, dissolved oxygen, pH value, nitrite and ammonia nitrogen of the aquaculture water body were monitored every day, the daily feeding amount was recorded, and the weight of mandarin fish, weight gain rate, specific growth rate, feed coefficient and survival rate were measured after the experiment; the liver was dissected for liver enzyme activity detection, blood was drawn to measure serum related enzyme activity indexes, and the whole fish was preserved to measure the general nutritional components of the body.

[0028] 3. Data processing

[0029] After the experiment, the average weight of juvenile fish in each group was measured, and the calculation formulas for growth indexes were as follows:

[0030] Weight gain rate WGR (%) = (average final weight - average initial weight) / average initial weight × 100%;

[0031] Specific growth rate SGR (% / d) = ln(average final weight / average initial weight) × 100% / number of experimental days;

[0032] Feed conversion ratio FCR = feed consumption / weight gain;

[0033] Survival rate SR (%) = (number of survivors / initial number) × 100%;

[0034] Domestication rate DR (%) = (number of fish starting to feed / initial number) × 100%.

[0035] The data were statistically analyzed using SPSS 27.0. Before analyzing the data, a homogeneity of variance test was used. Under the condition of meeting the test, one-way analysis of variance (one-way ANOVA) was used and multiple comparisons were made using Duncan's method. The experimental results were expressed as mean ± standard error (Mean ± S.E), and P < 0.05 was used as the criterion for judging significant differences.

[0036] 4. Results and analysis

[0037] 4.1 Effects of different attractants on the growth performance of juvenile topmouth culter

[0038] The growth performance of juvenile Siniperca chuatsi is shown in Table 1. The weight gain rates of Siniperca chuatsi with black soldier fly larvae paste, squid paste, and betaine added to the bait were all higher than those of the control group. Among them, there were significant differences in the groups with black soldier fly larvae paste and squid paste added (P<0.05). The specific growth rate of Siniperca chuatsi with squid paste added to the bait was significantly higher than that of the control group (P<0.05). The feed conversion ratios of the three groups with feeding attractants added were all lower than those of the control group, while the survival rate and domestication rate were both higher than those of the control group. Therefore, using squid paste for the domestication of Siniperca chuatsi fry helps to improve the success rate of domestication, promotes growth, and can reduce the feed conversion ratio. In the present invention, both squid paste and black soldier fly larvae paste are feeding stimulants of animal origin, and they have good feeding attraction effects. Betaine is an active methyl substance that can provide active methyl donors, and these substances have a certain feeding attraction effect. However, in this example, it is not as effective as the feeding attractant of animal origin, which may be related to the unique taste receptors of Siniperca chuatsi.

[0039] Table 1 Effects of different feeding attractants on the growth performance of juvenile Siniperca chuatsi

[0040] Control group Hermetia illucens insect paste Squid paste Betaine Initial weight IW (g) 5.81±0.14 5.81±0.14 5.81±0.14 5.81±0.14 Final weight FW (g) 22.35±1.21a 24.12±0.89b 24.87±0.78b 23.45±0.81ab Weight gain rate WG (%) 284.68±0.20a 315.15±0.19b 328.06±0.07b 303.61±0.31ab Specific growth rate SGR (% / d) 16.84±2.43a 17.79±1.04ab 18.18±1.37b 17.44±2.01ab Feed conversion ratio FER 1.92 1.71 1.56 1.79 Survival rate SR (%) 71.2 79.3 81.5 75.6 Domestication rate DR (%) 77.5 85.2 85.8 84

[0041] Note: Different letters in the same row indicate extremely significant differences (P<0.05), and the same applies to the following table.

[0042] 4.2 Effects of different feeding attractants on the body nutrient components of juvenile Siniperca chuatsi

[0043] Adding black soldier fly larvae paste, squid paste, and betaine to the bait had no effect on the body moisture of Siniperca chuatsi. However, the addition of the three feeding attractants significantly increased the crude protein content of juvenile Siniperca chuatsi (P<0.05), and the addition of black soldier fly larvae paste significantly increased the crude fat content of the body (P<0.05).

[0044] Specifically: During the domestication stage of Siniperca chuatsi fry, the addition of black soldier fly larvae paste and squid paste significantly increased the crude protein content of their bodies. Black soldier fly larvae paste and squid paste contain bioactive substances such as free amino acids and small peptides, which promoted the balance and absorption of amino acids during the growth of Siniperca chuatsi, thereby improving the feed efficiency and protein deposition. The addition of black soldier fly larvae paste significantly increased the crude fat content of the body, and the reason may be related to its lipid content.

[0045] Table 2 Effects of different feeding attractants on the body nutrient components of juvenile Siniperca chuatsi

[0046]

[0047]

[0048] 4.3 Effects of different feeding attractants on the serum biochemical indexes of juvenile Siniperca chuatsi

[0049] As can be seen from Table 3, adding squid paste and betaine to the bait can significantly increase the activity of aspartate aminotransferase in the blood (P<0.05). Adding squid paste to the bait can significantly increase the activity of alanine aminotransferase in the blood (P<0.05). Adding the three attractants has no significant effect on the content of alkaline phosphatase (P<0.05). Adding squid paste to the bait significantly reduces the content of total protein in the blood (P<0.05).

[0050] Specifically: Adding squid paste and betaine can significantly increase the activity of AST in the blood, and squid paste significantly increases the activity of ALT in the blood. The reason may be that low-freshness squid paste is used. Since squid is rich in moisture and unsaturated fatty acids, it is extremely prone to rancidity and deterioration during storage, transportation, and feed processing. Moreover, adding squid paste to the bait significantly reduces the content of total protein in the blood, which may be related to the freshness of squid paste and affects intestinal immunity. However, its role in promoting feeding, increasing the weight gain rate, and improving feed utilization cannot be ignored. Therefore, fresh squid paste should be selected and used for a short period during the early domestication stage to avoid negative impacts on fish immunity caused by long-term use.

[0051] Table 3 Effects of different attractants on serum biochemical indexes of juvenile Siniperca chuatsi

[0052] Index Control Hermetia illucens insect paste Squid paste Betaine Aspartate aminotransferase AST 18.38±3.73a 20.13±2.26a 59.91±5.78c 48.64±4.18bc Alanine aminotransferase ALT 10.11±1.79a 11.23±1.04a 15.90±2.24b 13.77±2.71a Alkaline phosphatase AKP 48.33±5.17 45.63±3.59 50.78±4.16 52.62±4.56 Total protein TP 26.46±0.51b 27.32±1.23b 23.14±1.07a 28.44±1.36b

[0053] 4.4 Effects of different attractants on the activities of nitrogen metabolism enzymes in the liver of juvenile Siniperca chuatsi

[0054] As can be seen from Table 4, adding squid paste and betaine to the bait both significantly reduce the activity of aspartate aminotransferase in the liver (P<0.05). There is no significant difference between adding black soldier fly larvae slurry and the control group (P>0.05). Adding betaine to the bait significantly reduces the activity of alanine aminotransferase in the liver (P<0.05). There is no significant difference between other groups and the control group (P>0.05). Adding black soldier fly larvae slurry and betaine to the bait both significantly increase the activity of glutamate dehydrogenase in the liver (P<0.05). There is no significant difference between adding squid paste and the control group (P>0.05).

[0055] Specifically, the activities of ALT and AST in the liver of mandarin fish acclimated with betaine attractant for 8 days were relatively low, indicating a relatively low degree of liver cell damage in mandarin fish. The reason may be that betaine, as an efficient methyl donor, can participate in the intermediate metabolism of choline, reduce fat accumulation and liver cell damage in the liver. Moreover, the addition of squid paste can significantly reduce the activity of AST, which is beneficial to reducing the burden on the liver of acclimated mandarin fish. Glutamate dehydrogenase (GDH) is mainly present in the liver. As a key rate-limiting enzyme in the deamination reaction of amino acids, the change in its activity reflects the catabolism of amino acids. The following table shows that black soldier fly larvae pulp and betaine significantly increase the activity of liver GDH. This indicates that black soldier fly larvae pulp and betaine will affect the amino acid catabolism in the liver during the acclimation process of mandarin fish. When the amino acids ingested by the body are unbalanced, catabolism in the body is greater than anabolism, and the amino acids in the body are used for energy consumption. This further proves the growth-promoting effect of squid paste in the acclimation of mandarin fish fry.

[0056] Table 4 Effects of Different Attractants on the Activities of Nitrogen Metabolism Enzymes in the Liver of Juvenile Topmouth Gudgeon

[0057] Control Hermetia illucens insect paste Squid paste Betaine Aspartate aminotransferase AST 59.46±2.45c 59.50±1.38c 40.35±3.19a 48.21±1.65b Alanine aminotransferase ALT 51.26±3.50b 43.76±3.19ab 46.61±1.95ab 37.56±2.55a Glutamate dehydrogenase GDH 217.08±12.11a 304.31±17.26bc 237.51±18.97ab 347.39±20.55c

[0058] The above experimental results show that: during the acclimation process of mandarin fish fry, the weight gain rates of mandarin fish with black soldier fly larvae pulp and squid paste added to the bait are higher than those of the control group; squid paste has a significant effect on the specific growth rate of mandarin fish. The feed coefficients of the three added attractants are lower than those of the control group, and the survival rate and acclimation rate are higher than those of the control group. In terms of physiological and biochemical indicators: the addition of the three attractants significantly increases the crude protein content of juvenile mandarin fish, and the addition of black soldier fly larvae pulp can significantly increase the crude fat content of the body. Squid paste can significantly increase the activities of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase in the blood, and squid paste can significantly reduce the content of total protein in the blood. Both squid paste and betaine significantly reduce the glutamic-oxaloacetic transaminase in the liver, but betaine also significantly reduces the activity of glutamic-pyruvic transaminase in the liver, and both black soldier fly larvae pulp and betaine significantly increase the activity of glutamate dehydrogenase in the liver. Therefore, the three attractants can all improve the feeding efficiency. Among them, squid paste has the most obvious effect on promoting the early growth performance, and the related physiological and metabolic indicators are excellent, while betaine reduces the liver metabolic burden during the acclimation process of mandarin fish.

[0059] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A domestication bait for mandarin fish fry, characterized in that: It includes live crucian carp fry and silver carp fry, half-dead crucian carp fry and half-dead silver carp fry, mandarin fish powder, a mixture of dead crucian carp fry and dead silver carp fry, and mandarin fish feed No. 0; an attractant is added to the powder, and the attractant is one of squid paste, betaine and black soldier fly paste.

2. The domestication bait for mandarin fish fry according to claim 1, characterized in that: The added amount of the attractant is 1.5% of the powder.

3. A method for domesticating mandarin fish fry, characterized in that: Feed the domesticated bait of mandarin fish fry according to claim 1 or 2 twice a day, with a daily feeding rate of 4%-5%, and feed until the fish are full each time. Before feeding, close the microporous oxygenation equipment, open the circulating water to impact the water surface, and stimulate the fish to gather.

4. The method for acclimating mandarin fish fry according to claim 3, characterized in that: The domestication process used live crucian carp fry and silver carp fry, half-dead crucian carp fry and half-dead silver carp fry, mandarin fish powder, a mixture of dead crucian carp fry and dead silver carp fry, and mandarin fish feed No. 0 for feeding.

5. The method for acclimating mandarin fish fry according to claim 4, characterized in that: Live crucian carp fry and silver carp fry were used for feeding in the first 2 days, and then half-dead crucian carp fry and half-dead silver carp fry were fed for 3 days. Then, dead crucian carp fry and half-dead silver carp fry were mixed with mandarin fish powder and fed. After acclimation for 3 days, they were switched to mandarin fish feed No.

0. The feed was soaked in water and then fed. The acclimation test period was 8 days in total.

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