CN114514967B - Fish feed containing structural grease OPO and preparation method and application thereof - Google Patents

Abstract

The invention provides a fish feed containing structural grease OPO, and a preparation method and application thereof, and belongs to the technical field of feed preparation, wherein the structural grease OPO comprises 3-25% by mass of the fish feed, palmitic acid in the structural grease OPO is mainly distributed on sn-2 position of a glycerol skeleton, and the unique fatty acid composition and position distribution have great influence on digestion, absorption and metabolism of fat, and have important effects of promoting fatty acid absorption, improving constipation, preventing mineral calcium loss, protecting liver and other physiological functions, and growing and developing.

Description

A kind of fish feed containing structural oil OPO and its preparation method and application

technical field

The invention belongs to the technical field of feed preparation, and in particular relates to a fish feed containing structural oil OPO and a preparation method and application thereof.

Background technique

Fish products have relatively comprehensive nutritional value, and fish products with high protein content are very important for improving dietary structure and improving human health. With the increasing concept of dietary therapy and health preservation, consumers have higher and higher requirements for the consumption and quality of fish products.

Generally, fish feed is processed from high-energy food raw materials. Long-term intake of high-fat and high-protein foods by the fish body can easily induce long-term accumulation of fat in the liver, forming fatty liver, and destroying liver function. Moreover, the digestive tract of fish is relatively short. , the fasting speed is fast, which may not completely digest the common structural oils in the feed, which not only reduces the absorption rate of lipids in the feed, but also affects the absorption of some fat-soluble minerals and vitamins, and finally reduces the growth rate of fish.

In the composition of ordinary structural oils, palmitic acid is mainly distributed on the sn-1 and 3 positions of the glycerol skeleton, while the sn-2 position is connected to saturated/or unsaturated fatty acids. Oils with this type of structure are generally difficult to be absorbed and utilized by the intestines.

Contents of the invention

In view of this, the object of the present invention is to provide a kind of fish feed containing structural oil OPO and its preparation method and application; The structural oil 1,3-dioleic acid-2-palmitic acid triglyceride Palmitic acid in the ester (OPO) is mainly distributed on the sn-2 position of the glycerol skeleton. This unique fatty acid composition and position distribution have a great influence on the digestion, absorption and metabolism of fat. It can promote the absorption of fatty acids, improve constipation, prevent Physiological functions such as mineral calcium loss play an important role in growth and development.

The invention provides a fish feed containing structured oil OPO, wherein the mass percentage of the structured oil OPO in the fish feed is 3% to 25%.

Preferably, the purity of the structural oil OPO is 45%-65%.

Preferably, the preparation method of the structured oil OPO comprises the following steps: mixing tripalmitin triglyceride, oleic acid and lipase, and reacting at 58-62° C. for 5-7 hours to obtain the structured oil OPO; the tripalmitin glycerin The molar ratio of triester and oleic acid is 1: (8-10), and the amount of lipase is 13%-15% of the total mass of tripalmitin triglyceride and oleic acid.

Preferably, the following components are included in parts by weight: 0.32-0.96 parts of fish meal, 0.08-0.24 parts of corn gluten meal, 0.48-1.44 parts of soybean meal, 0.12-0.48 part of peanut meal, 0.134-0.402 parts of flour, and 0.6-2.4 parts of chicken meal , 0.06-0.24 parts of yeast, 0.01-0.03 parts of freshwater fish premix, 0.002-0.008 parts of choline chloride, 0.02-0.08 parts of calcium dihydrogen phosphate, 0.04-0.016 parts of methionine, 0.04-0.16 parts of α-starch and structure Grease OPO 0.36-0.48 parts.

Preferably, the concentration of the choline chloride is 35%-65%.

Preferably, the yeast is brewer's yeast.

The present invention also provides the preparation method of described fish feed, comprises the following steps:

(1) Fish meal, flour, α-starch and chicken powder are mixed to obtain the first mixed material;

(2) Yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn gluten, soybean meal, peanut meal and freshwater fish premix are mixed to obtain the second mixed material:

(3) Mixing the first mixed material obtained by the structural oil OPO with the step (1) and the second mixed material obtained by the step (2) to obtain the third mixed material;

(4) Granulating, cooling and drying the third mixed material obtained in step (3) to obtain fish feed.

Preferably, the particle size of the granulation is 1-4mm.

The invention also provides the application of the fish feed in preparing medicine or functional feed for protecting fish liver.

The invention also provides the application of the fish feed in the preparation of medicine or functional feed for lowering blood fat.

Compared with the prior art, the present invention has the following beneficial effects: palmitic acid in the structural oil 1,3-dioleic acid-2-palmitic acid triglyceride (OPO) in the fish feed containing the structural oil OPO provided by the invention It is mainly distributed on the sn-2 position of the glycerol skeleton. This unique fatty acid composition and position distribution has a great influence on the digestion, absorption and metabolism of fat, and has physiological functions such as promoting fatty acid absorption, improving constipation, and preventing mineral calcium loss. , plays an important role in growth and development.

Further, the structured oil OPO lipid in the fish feed provided by the present invention cooperates with other raw materials in the fish feed to achieve a reasonable coordination of fat, vitamins, minerals, etc. Adding it to the fish feed can not only improve the fish's sensitivity to It not only promotes the absorption of lipids, but also promotes the absorption of fat-soluble minerals and vitamins by the fish body, significantly improves the quality of fish meat and reduces the index of serum liver enzyme activity, which is conducive to protecting the health of the liver.

Detailed ways

The invention provides a fish feed containing structured oil OPO, wherein the mass percentage of the structured oil OPO in the fish feed is 3% to 25%.

In the present invention, the full name of the structured oil OPO is 1,3-dioleic acid-2-palmitic acid triglyceride.

In the present invention, the mass percentage of the structured oil OPO in the fish feed is preferably 5%-21%, more preferably 6%-10%. In the present invention, the purity of the structural oil OPO is preferably 45%-65%, more preferably 50%-60%.

The present invention has no special limitation on the source and preparation method of the structured oil OPO, and the structured oil OPO meeting the above-mentioned purity limit can be prepared by using commercially available products or conventional methods in the field. In the specific implementation process of the present invention, the preparation method of the structured oil OPO preferably includes the following steps: mixing tripalmitin triglyceride PPP, oleic acid and lipase, reacting at 58-62°C for 5-7 hours to obtain the structured oil OPO. In the present invention, the molar ratio of the tripalmitin triglyceride and oleic acid is preferably 1: (8-10), more preferably 1:9; the lipase is preferably specific 1, 3 specific Sexual lipase, described lipase is preferably the lipase immobilized by macroporous resin; The consumption of described lipase is preferably 13%～15% of the total mass of tripalmitin triglyceride and oleic acid, more preferably 14% . In the present invention, the temperature of the reaction is more preferably 59-61° C., even more preferably 60° C.; the reaction time is preferably 5.5-6.5 hours, more preferably 6 hours.

In the present invention, the tripalmitin triglyceride PPP is preferably prepared by recrystallization, and the tripalmitin triglyceride PPP prepared by the recrystallization method has high purity. In the present invention, the preparation method of the tripalmitin triglyceride PPP comprises the following steps: dissolving palm stearin in acetone at 65-75° C. and then carrying out recrystallization at lower temperature, and the procedure for the recrystallization at lower temperature is to lower the temperature every 15 minutes. 10°C, until the temperature drops to 35-37°C, carry out suction filtration and separation to obtain the solid tripalmitin triglyceride, and remove the solvent by rotary evaporation under reduced pressure to obtain the crude product of the tripalmitin triglyceride, then the tripalmitin triglyceride The crude ester was repeatedly eluted to obtain high-purity tripalmitin triglyceride PPP. In the present invention, the dissolution temperature of the repeated dissolution is 74-76°C, more preferably 75°C, the precipitation temperature of the repeated dissolution is preferably 19-21°C, more preferably 20°C; the repeated dissolution The frequency of analysis is preferably 2 to 3 times. In the present invention, after the repeated elution, it is preferred to remove residual impurities at the edge of the crystal to obtain high-purity tripalmitin triglyceride PPP. In the present invention, the high-purity tripalmitin triglyceride PPP is preferably evaporated with nitrogen and then refrigerated for future use.

In the present invention, the fish feed preferably includes the following components in parts by weight: 0.32-0.96 parts of fish meal, 0.08-0.24 parts of corn gluten meal, 0.48-1.44 parts of soybean meal, 0.12-0.48 part of peanut meal, 0.134-0.402 part of flour 0.6-2.4 parts of chicken powder, 0.06-0.24 parts of yeast, 0.01-0.03 parts of freshwater fish premix, 0.002-0.008 parts of choline chloride, 0.02-0.08 parts of calcium dihydrogen phosphate, 0.04-0.016 parts of methionine, α - 0.04-0.16 parts of starch and 0.36-0.48 parts of structured oil OPO.

In the present invention, the concentration of the choline chloride is preferably 35%-65%. In the present invention, the yeast is preferably brewer's yeast. The present invention has no special limitation on the sources and specifications of other raw materials in the fish feed, and conventional sources and specifications in the field can be used.

The present invention also provides the preparation method of said fish feed, comprising the following steps: (1) mixing fish powder, flour, α-starch and chicken powder to obtain the first mixed material; (2) mixing yeast, cholerin Alkali, calcium dihydrogen phosphate, methionine, corn gluten powder, soybean meal, peanut meal and freshwater fish premix are mixed to obtain the second mixed material: (3) the first mixed material obtained by the structural oil OPO and step (1) and mixing the second mixed material obtained in step (2) to obtain a third mixed material; (4) granulating, cooling and drying the third mixed material obtained in step (3) to obtain fish feed.

In the present invention, the particle size of the granulation is preferably 1-4 mm, more preferably 1.5 mm. In the present invention, there is no special limitation on the specific operations of the granulation, cooling and drying, and conventional methods in the field can be used.

The invention also provides the application of the fish feed in preparing medicine or functional feed for protecting fish liver. The invention also provides the application of the fish feed in the preparation of medicine or functional feed for lowering blood fat. The fish feed provided by the invention can significantly increase the content of serum HDL-C, can reduce the content of blood lipids such as cholesterol and triglyceride to a certain extent, is beneficial to body fat metabolism, and protects the health of the liver.

The technical solutions provided by the present invention will be described in detail below in conjunction with the examples, but they should not be interpreted as limiting the protection scope of the present invention.

Example 1

Preparation of Tripalmitin Triglyceride PPP

Dissolve palm stearin with acetone at 70°C, then carry out the recrystallization procedure in an artificial climate box, lower the temperature at a constant rate, 10°C every 15 minutes, recrystallize at a lower temperature, reach 36°C, and separate by rapid suction filtration to obtain tripalmitin glycerin The ester solid was removed by rotary evaporation under reduced pressure to obtain the crude product of tripalmitin triglyceride; the obtained crude product of tripalmitin triglyceride PPP was repeatedly eluted under the conditions of sudden cooling and sudden heating, dissolved at 75 ° C, and dissolved at 20 Rapid cooling at ℃, repeated elution for 3 times, precipitated oil crystals with good crystal form, and high-purity PPP can be obtained after removing residual impurities on the edge of the crystals, followed by evaporating PPP with nitrogen gas, and refrigerated for later use.

The preparation steps of immobilized lipase are:

(1) Pretreatment of enzyme carrier macroporous acrylic resin: soak the new resin ANL@MARE in 95% ethanol for 3 hours, and stir several times during the process. Then the ethanol was removed by suction filtration, and the resin was washed with deionized water until there was no obvious smell of ethanol, and then stored.

Preparation method of resin ANL@MARE

With 80.5 g monomer phase [monomer (20.7 g methyl methacrylate), crosslinker (13.8 g divinylbenzene), initiator (0.8 g azobisisobutyronitrile)] and 45.2 g inert components A mixture of (36.2 g toluene and 9.0 g n-heptane) was used as the monomer phase. The aqueous phase consisted of 240.0 g water, 0.5 g gelatin and 2.4 g polyvinyl alcohol.

The monomer phase was dispersed into the water phase to prepare an emulsion, and then stirred in a four-neck glass flask, the copolymerization reaction was carried out at 70°C for 2h, then at 80°C for 6h, and the stirring speed was 200rpm. After the reaction was completed, the copolymer particles were washed with water and ethanol, kept in ethanol for 12 h, and then dried in a vacuum oven at 45 °C for 24 h.

The resin carrier with suitable pore size was screened, and the characterization structure of ANL@MARE is shown in Table 1.

Table 1 Characterization structure of resin ANL@MARE

(2) Preparation of immobilized enzyme:

Weigh 12.5mg of Aspergillus niger lipase and dissolve it in 2.5mL 20mM phosphate buffer solution, let it stand until fully dispersed, centrifuge at 4°C, 10000rpm for 10min, take the supernatant, and make a 5mg/mL lipase solution; Weigh 100mg dry weight resin by dry-wet ratio, disperse in 20mM phosphate buffer solution, rinse the resin with buffer solution three times, and finally disperse in 2.5mL buffer solution, ultrasonic treatment for 15min, so that the buffer solution and resin are fully Contact; take the lipase solution, add it to the resin dispersion, place it in an air bath constant temperature shaker, and react for 2 hours at 200rpm at 35°C to make the lipase fully adsorb to the resin; after the reaction, use phosphate buffer solution to immobilize the enzyme Rinse three times to remove residual lipase on the surface, then place it in a vacuum dryer at 35°C for 5 hours to remove moisture, and finally store it in a dry environment at 4°C.

(3) Preparation of modified structure oil OPO

Using tripalmitin triglyceride and oleic acid as raw materials, OPO was synthesized by transesterification catalyzed by lipase ANL@MARE. The reaction conditions were that the molar ratio of PPP and oleic acid was 1:9, the reaction temperature was 60°C, the amount of enzyme added was 14% (based on the total mass of the substrate), and the reaction time was 6h. The modified structure oil OPO obtained under these conditions The purity is 67.25%.

The raw materials and dosage of fish feed are: 0.96 parts of fish meal, 0.24 parts of corn gluten meal, 1.44 parts of soybean meal, 0.36 parts of peanut meal, 0.402 parts of flour, 1.8 parts of chicken meal, 0.18 parts of yeast, 0.03 parts of freshwater fish premix, 0.006 part of choline chloride, 0.06 part of calcium dihydrogen phosphate, 0.012 part of methionine, 0.12 part of α-starch and 0.36 part of modified structural oil OPO.

The preparation method is as follows:

(a) mixing fish meal, flour, α-starch and chicken powder to obtain the first mixed material;

(b) Mix brewer's yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn gluten, soybean meal, peanut meal and freshwater fish premix to obtain the second mixed material:

(c) mixing the modified structure grease OPO with the first mixed material obtained in step (1) and the second mixed material obtained in step (2) to obtain the third mixed material;

(d) Granulating the third mixed material, then cooling and air-drying to finally obtain fish feed with a particle size of 1.5mm.

Example 2

Refer to the method described in Example 1 for the preparation of the modified structured oil OPO.

The raw materials and dosage of fish feed are: 0.32 parts of fish meal, 0.08 parts of corn gluten meal, 0.48 parts of soybean meal, 0.12 parts of peanut meal, 0.134 parts of flour, 0.6 parts of chicken meal, 0.06 parts of yeast, 0.01 part of freshwater fish premix, 0.002 part of choline chloride, 0.02 part of calcium dihydrogen phosphate, 0.04 part of methionine, 0.04 part of α-starch and 0.36 part of modified structural oil OPO.

The preparation method is as follows:

(a) mixing fish meal, flour, α-starch and chicken powder to obtain the first mixed material;

(b) Mix brewer's yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn gluten, soybean meal, peanut meal and freshwater fish premix to obtain the second mixed material:

(c) mixing the modified structure grease OPO with the first mixed material obtained in step (1) and the second mixed material obtained in step (2) to obtain the third mixed material;

(d) Granulating the third mixed material, then cooling and air-drying to finally obtain fish feed with a particle size of 2 mm.

Example 3

Refer to the method described in Example 1 for the preparation of the modified structured oil OPO.

The raw materials and dosage of fish feed are: 0.96 parts of fish meal, 0.24 parts of corn gluten meal, 1.44 parts of soybean meal, 0.48 parts of peanut meal, 0.402 parts of flour, 2.4 parts of chicken meal, 0.24 parts of yeast, 0.03 parts of freshwater fish premix, 0.008 part of choline chloride, 0.08 part of calcium dihydrogen phosphate, 0.016 part of methionine, 0.16 part of α-starch and 0.48 part of modified structural oil OPO.

The preparation method is as follows:

(a) mixing fish meal, flour, α-starch and chicken powder to obtain the first mixed material;

(b) Mix brewer's yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn gluten, soybean meal, peanut meal and freshwater fish premix to obtain the second mixed material:

(c) mixing the modified structure grease OPO with the first mixed material obtained in step (1) and the second mixed material obtained in step (2) to obtain the third mixed material;

(d) Granulating the third mixed material, then cooling and air-drying to finally obtain fish feed with a particle size of 3 mm.

Comparative example 1 (common structure oil control group)

The raw materials and dosage of fish feed are: 0.96 parts of fish meal, 0.24 parts of corn gluten meal, 1.44 parts of soybean meal, 0.36 parts of peanut meal, 0.402 parts of flour, 1.8 parts of chicken meal, 0.18 parts of yeast, 0.03 parts of freshwater fish premix, 0.006 part of choline chloride, 0.06 part of calcium dihydrogen phosphate, 0.012 part of methionine, 0.12 part of α-starch and 0.36 part of ordinary structured oil palm oil.

According to above-mentioned raw material and addition amount, the concrete steps of the preparation method of fish feed comprise:

(1) Mix fish meal, flour, α-starch and chicken powder to obtain the first mixed material;

(2) Mix brewer's yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn gluten, soybean meal, peanut meal and freshwater fish premix to obtain the second mixed material:

(3) mixing palm oil with the first mixed material obtained in step (1) and the second mixed material obtained in step (2) to obtain the third mixed material;

(4) Granulating the third mixed material, then cooling and air-drying to obtain fish feed with a particle size of 1.5 mm.

Comparative example 2 (oil control group PPP before structural modification)

The raw materials and dosage of fish feed are: 0.96 parts of fish meal, 0.24 parts of corn gluten meal, 1.44 parts of soybean meal, 0.36 parts of peanut meal, 0.402 parts of flour, 1.8 parts of chicken meal, 0.18 parts of yeast, 0.03 parts of freshwater fish premix, 0.006 part of choline chloride, 0.06 part of calcium dihydrogen phosphate, 0.012 part of methionine, 0.12 part of α-starch and 0.36 part of tripalmitin triglyceride PPP.

According to above-mentioned raw material and addition amount, the concrete steps of the preparation method of fish feed comprise:

(1) Mix fish meal, flour, α-starch and chicken powder to obtain the first mixed material;

(2) Mix brewer's yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn gluten, soybean meal, peanut meal and freshwater fish premix to obtain the second mixed material:

(3) mixing the grease before structural modification, the first mixed material obtained in step (1), and the second mixed material obtained in step (2), to obtain a third mixed material;

(4) Granulating the third mixed material, then cooling and air-drying to obtain fish feed with a particle size of 1.5 mm.

Experimental example

Further effect detection was carried out on the above embodiment 1 and comparative examples 1-2.

270 healthy and disease-free perch with similar weight (7.65±0.55) g and body length (7.90±0.71) cm were selected and randomly divided into 3 groups with 3 replicates in each group and 30 fish in each replicate. Group 1 is the experimental group, which is fed with the fish feed prepared in Example 1. The control group was fed the fish feed prepared in Comparative Example 1-2, and the groups 2-3 were the control group, and fed the fish feed prepared in Comparative Example 1 and Comparative Example 2 respectively.

The test was carried out in a water circulation aquaculture system. During the test period, the aeration was continued for 24 hours, and the water in the breeding tank was changed regularly according to the water quality. The animals were fed once at 8 o'clock in the daytime and 6 o'clock in the night. The feeding amount, water temperature and mortality were recorded every day. Breeding conditions: dissolved oxygen concentration>8.0mg/L, natural light source, average water temperature 28.8°C, ammonia nitrogen concentration<0.06mg/L, nitrite concentration<0.05mg/L, pH7.6～8.0. The test period is 56 days. One week after the pre-test, the formal test was started for 56 days. After 56 days, the growth indicators of the above-mentioned perch were analyzed, including body weight, weight growth rate, specific growth rate, survival rate, liver body index and feed coefficient and other indicators.

The specific calculation formula and determination method are as follows:

Weight gain (g) = final average weight - initial average weight;

Weight gain rate (%) = weight gain/initial average weight × 100%;

Survival rate (%)=the number of fish at the end of the experiment/the number of fish at the beginning of the experiment×100%;

Specific growth rate (%/day) = [In (average weight at the end)-In (average weight at the beginning and end)]/test days×100%;

Feed factor (%) = total amount fed/body weight gain × 100%;

Fullness (%) = (cube of body weight/body length) × 100%;

Liver body index (%) = liver weight/fish body weight × 100%;

Intestinal body ratio (%) = (intestinal length/body length) × 100%;

Visceral weight index (%) = (visceral weight/fish body weight) × 100%;

Abdominal fat index (%)=(abdominal fat weight/fish body weight)×100%.

Determination of muscle texture

A physical property tester is used for measurement. By simulating the chewing movement of the oral cavity, the sample is compressed twice to measure the hardness, elasticity, elasticity, viscosity, fracture, cohesion, chewiness and adhesiveness of the muscle.

The texture properties were determined by a texture analyzer (Universal TA) produced by Shanghai Tengba Instrument Technology Co., Ltd. Remove the dorsal muscle of the measured experimental fish, use the TA10 probe in TPA mode, test speed: 1.00mm/s, return speed: 1.0mm/s, data frequency: 50.00points/sec, cycle number: 2.0.

Muscle pH was measured with a pH meter. Each experimental fish was measured three times at different parts of the muscles on both sides, and the average value was taken.

Muscle cooked meat rate (%): Take about 5g of dorsal muscle (W1) and put it in boiling water, take it out after 5 minutes, dry the surface water with filter paper, weigh it after cooling (W2). Calculation formula: CP=W2/W1×100%

Muscle water holding rate (%): take about 5g of dorsal muscle (W1) and place it on qualitative filter paper, then cover it with a piece of filter paper, squeeze it with a 1kg weight for 5 minutes, and weigh the muscle mass (W2).

Calculation formula: WHC=(W2-W1)/W1×100%

Serum indicators, using automatic serum biochemical analyzer

As can be seen from Table 2, Example 1 and Comparative Examples 1-2 have no significant impact on the weight gain, weight gain rate, specific growth rate, feed conversion ratio and survival rate of California juvenile fish. But the feed coefficient of embodiment 1 is lower, and the feed conversion rate improves, and the use effect is better.

It can be seen from Table 3 that the growth performance of California sea bass is mainly affected by the fatty acid composition of oil, and California sea bass has different digestion and utilization rates of different fatty acids linked to the glycerol skeleton. Feeding the feed of Example 1 had a significant effect on the liver body index of juvenile California fish, which may be because the structural oil added to this feed is more conducive to the metabolism of the fish and the development of the liver is healthier. In comparative example 2, the feed containing more saturated fatty acid oil was added, and the metabolism of the fish body to the saturated fatty acid contained in the sn-2 position on the glycerol skeleton was poor, and the visceral mass index decreased. The abdominal fat index of the comparison group 2 was significantly different, which also indicated that the fish body could not digest and absorb this structural oil, which affected the deposition of fat in the abdominal cavity of California sea bass.

It can be seen from Table 4 that Example 1 and Comparative Examples 1-2 have no significant effect on the pH and water holding capacity of California juvenile fish muscle. The cooked meat rate of Example 1 is significantly higher than that of Comparative Example 2.

It can be seen from Table 5 that the activities of alanine aminotransferase and aspartate aminotransferase in Example 1 were significantly reduced. ALT and AST mainly exist in liver cells. Generally speaking, their activity is an index to measure liver function. Under normal circumstances, their activity in blood is low and relatively stable. Only when the liver is damaged, it will be in the blood. Significantly increased enzyme activity in the blood. The results of this test show that the ALT and AST activities in the serum of California perch in Example 1 are significantly reduced, which shows that under the feed feeding with this kind of structurally modified oil, OPO can improve the health of the California perch liver to a certain extent, and promote fat metabolisim.

HDL-C is a kind of blood lipoprotein, which can transport cholesterol, triglyceride and other substances outside the liver to the liver for decomposition, and prevent the deposition of cholesterol on the blood vessel wall. Adding OPO to feed can significantly increase the content of serum HDL-C, and to a certain extent can reduce the content of blood lipids such as cholesterol and triglyceride, which is beneficial to the body's fat metabolism and protects the health of the liver.

It can be seen from Table 6 that Example 1 can significantly enhance the hardness and glueiness of fish. The hardness of fish is related to the muscle fibers. The muscle fibers of fish body are smaller in diameter and arranged more tightly. Macroscopically, the hardness is higher, and the touch feels more vigorous. The texture characteristics of fish meat are mainly affected by the content of protein, water and fat. The higher the protein and fat content of fish meat, the better the glueiness of the meat quality, and the macroscopic performance of the meat quality is "refreshing".

Table 2 Effects on Growth Performance

Group/Indicator weight gain/g Weight gain/% Specific growth rate/(%/d) Feed factor/% Survival rate/% Comparative example 1 49.92±2.23a 769.69±43.26 3.860±09a 87.09±2.41a 100a Comparative example 2 46.95±0.76a 749.76±25.98 3.82±0.05a 90.34±1.93a 100a Example 1 46.76±1.83a 746.16±26.13 3.81±0.06a 85.09±3.64a 100a

Different lowercase letters after the data in the same row indicate significant differences (P<0.05), the same or no letters indicate no significant differences (P>0.05), the same below.

Table 3 The impact of shape indicators

Group/Indicator Fullness/% Abdominal Fat Index/% Enterotosome ratio/% Liver body index % visceral mass index/% Comparative example 1 2.39±0.09b 2.72±0.07c 87.69±1.75a 1.31±0.04a 7.38±0.29b Comparative example 2 2.25±0.02a 1.61±0.05a 86.39±1.13a 1.27±0.02a 5.73±0.64a Example 1 2.16±0.03a 2.07±0.06b 83.51±0.98a 1.64±0.20b 7.27±0.41b

Table 4 The impact of edible indicators

Group/Indicator pH Muscle cooked meat rate/% Muscle water retention/% Comparative example 1 6.44±0.08a 87.69±1.75a 97.73±0.28a Comparative example 2 6.37±0.03a 83.34±0.36b 97.04±0.14a Example 1 6.42±0.06a 90.72±0.24c 96.87±0.22a

Table 5 The influence of serum biochemical indicators

Table 6 fish body texture index

Index/group Comparison group 1 Comparison group 2 Example 1 Hardness/g 76.33±12.42ab 58.00±4.58a 78.33±10.21b Elasticity/N 0.49±0.02a 0.58±0.05b 0.48±0.02a Viscosity/g 4.33±0.58a 4.67±0.58a 4.36±0.38a Breakability/g 8.67±1.53b 6.11±1.07a 6.67±0.88ab Cohesion 0.78±0.06a 0.79±0.09a 0.76±0.07a Elasticity/mm 1.09±0.03a 1.03±0.09a 1.01±0.06a Adhesiveness/g 48.67±7.77a 43.89±2.71a 58.42±1.42b Chewiness/mJ 0.57±0.06a 0.56±0.05a 0.52±0.07a

As can be seen from the foregoing examples, the structure oil OPO lipid in the fish feed provided by the present invention cooperates with other raw materials in the fish feed to achieve a reasonable combination of fat, vitamins, minerals, etc. Adding it to the fish feed can not only Improve the fish's absorption of lipids, and promote the fish's absorption of fat-soluble minerals and vitamins, significantly improve the quality of fish meat and reduce serum liver enzyme activity indicators, which is conducive to protecting the health of the liver.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (5)

1. The fish feed containing the structural grease OPO is characterized by comprising the following components in parts by weight: 0.32 to 0.96 part of fish meal, 0.08 to 0.24 part of corn gluten meal, 0.48 to 1.44 part of bean pulp, 0.12 to 0.48 part of peanut meal, 0.134 to 0.402 part of flour, 0.6 to 2.4 parts of chicken meal, 0.06 to 0.24 part of yeast, 0.01 to 0.03 part of freshwater fish premix, 0.002 to 0.008 part of choline chloride, 0.02 to 0.08 part of monocalcium phosphate, 0.04 to 0.016 part of methionine, 0.04 to 0.16 part of alpha-starch and 0.36 to 0.48 part of structural grease OPO;

the purity of the OPO of the structural grease is 45% -65%;

the preparation method of the structural grease OPO comprises the following steps: mixing tripalmitin triglyceride, oleic acid and lipase, and reacting at 58-62 ℃ for 5-7 h to obtain structural grease OPO; the mole ratio of tripalmitin to oleic acid is 1: (8-10), wherein the dosage of the lipase is 13-15% of the total mass of the tripalmitin triglyceride and the oleic acid;

the concentration of the choline chloride is 35% -65%;

the yeast is beer yeast.

2. A method of preparing a fish feed as claimed in claim 1, comprising the steps of: (1) Mixing fish meal, flour, alpha-starch and chicken meal to obtain a first mixed material; (2) Mixing yeast, choline chloride, calcium dihydrogen phosphate, methionine, corn protein powder, soybean meal, peanut meal and freshwater fish premix to obtain a second mixed material: (3) Mixing the structural grease OPO with the first mixed material obtained in the step (1) and the second mixed material obtained in the step (2) to obtain a third mixed material; (4) Granulating, cooling and drying the third mixed material obtained in the step (3) to obtain the fish feed.

3. A method of preparing a fish feed according to claim 2, wherein the particle size of the pelletising is 1-4 mm.

4. The fish feed of claim 1 and the fish feed prepared by the preparation method of claim 2 are applied to preparing functional feed for protecting fish livers.

5. The fish feed of claim 1, the fish feed prepared by the preparation method of claim 2 or 3, and the application of the fish feed in preparing functional feed for reducing blood fat.