阅读说明：本技术 三种泥鳅的肌肉营养成分与消化酶活力的分析研究 (Analysis and research on muscle nutrient content and digestive enzyme activity of three loaches ) 是由 冒树泉 张媛媛 成慧中 王秉利 许�鹏 胡斌 吴君 于 2021-03-10 设计创作，主要内容包括：本发明公开了一种三种泥鳅的肌肉营养成分与消化酶活力的分析研究,选取泥鳅、大鳞副泥鳅和台湾大泥鳅三个群体,并对其开展营养成分及消化酶活性的分析研究,包括常规营养成分的测定、组织消化酶的测定和肌肉营养品质的评价。结果表明,三种泥鳅粗脂肪含量均高于3.5%,表明三种泥鳅肌肉均具有良好的风味与口感；三种泥鳅中氨基酸含量丰富,属于高蛋白鱼类；三种泥鳅中多不饱和脂肪酸含量较高,经常食用泥鳅可以提高身体免疫力,降低疾病的发生几率。(The invention discloses an analytical study on muscle nutrient components and digestive enzyme activity of three loaches, which selects three groups of loaches, loaches and Misgurni Anguillicaudati, and carries out analytical study on the nutrient components and the digestive enzyme activity of the three groups of the loaches, wherein the analytical study comprises the measurement of conventional nutrient components, the measurement of tissue digestive enzyme and the evaluation of muscle nutrient quality. The results show that the crude fat content of the three loaches is higher than 3.5%, and the muscle of the three loaches has good flavor and mouthfeel; the loaches are rich in amino acid content and belong to high-protein fishes; the three kinds of loaches have high polyunsaturated fatty acid content, and the loaches can improve the body immunity and reduce the occurrence probability of diseases after being eaten frequently.)

1. The analytical research on the muscle nutrient content and the digestive enzyme activity of three loaches is characterized in that: the method comprises the following steps:

a. selection of test materials

Randomly selecting 30 loaches (MA), Paramisgurnus Dabryanus (PD) and Taiwan loach (TW) which are strong in physique and have no damage to body surfaces, and preparing for dissection;

b. sample processing

Anaesthetizing the fish body by adopting MS-222 before dissecting the fish body, taking muscles on two sides of the back of the fish body after anaesthetizing, wiping the muscles by using filter paper, mashing the muscles and uniformly mixing the muscles to prepare a sample, averagely dividing the sample into two parts, wherein one part is used for measuring conventional nutrient components, and the other part is placed in a refrigerator for freezing and storing at the temperature of 20 ℃ below zero, and is used for measuring amino acid and fatty acid after freezing and drying;

c. evaluation of muscle nutritional quality

Assessment of muscle nutritional value the Amino Acid Score (AAS), Chemical Score (CS) and Essential Amino Acid Index (EAAI) were calculated according to the following formulas, respectively, based on the amino acid score standard pattern (%, dry) and the amino acid pattern of whole egg protein (%, dry) recommended by FAO/WHO in 1973:

in the formula: aa is the amino acid content (%) of the test sample; AA (FAO/WHO) is the content (%) of the same amino acid in a FAO/WHO scoring standard mode; AA (egg) is the content (%) of the same amino acid in the whole egg protein; n is the number of essential amino acids to be compared; a, B, C, …, H is the essential amino acid content (%, dry) of the sample muscle protein; AE, BE, CE, …, HE is the essential amino acid content (%, dry) of whole egg proteins;

d. determination of tissue digestive enzymes

In the sample processing process, 6 loaches of each loach are respectively narcotized by MS-222 and placed on an ice tray, an intestinal tract and a liver and pancreas are dissected and taken out, food and excrement in the intestinal tract are removed, intestinal wall fat is removed, and the loaches are stored in a refrigerator at the temperature of minus 20 ℃ for freezing and standby after being washed by deionized water; the activity of protease, lipase and amylase in the intestinal tract and the liver and pancreas is measured by adopting a kit;

e. the measured test data were biometrically measured using the SPSS17.0 software, and descriptive statistics were expressed using mean ± standard error (mean ± SD).

2. The analytical study on muscle nutrient content and digestive enzyme activity of three loaches according to claim 1, wherein the analytical study is carried out by the following steps: the test material is taken from an aquaculture farm in Linyi city, and the specifications of the three loaches are that the loaches have the body mass of (18.94 +/-0.73) g and the body length of (13.57 +/-0.59) cm respectively; the mass of the Paramisgurnus dabryanus is (17.35 +/-0.39) g, and the body length is (13.02 +/-0.40) cm; the body mass of the Taiwan loach is (20.17 +/-0.89) g, and the body length is (12.63 +/-0.70) cm.

3. The analytical study on muscle nutrient content and digestive enzyme activity of three loaches according to claim 1, wherein the analytical study is carried out by the following steps: the conventional nutrient content determination comprises determination of moisture, ash, crude protein and crude fat, wherein the moisture determination refers to GB5009.3-2010, and is determined by adopting a 105 ℃ drying and water loss method and a BGZ-246 electric heating constant temperature air drying oven; ash content is determined by a dry ashing method at 550 ℃ and a Thermo BF51794JC-1 muffle furnace according to GB/T5009.4-2010; the crude protein is determined by a FOSS 8400 full-automatic azotometer by adopting a trace Kjeldahl azotometer according to GB/T5009.5-2010; the crude fat is determined by a BUCHI E-812 full-automatic Soxhlet fat extractor according to GB/T5009.6-2008.

4. The analytical study on muscle nutrient content and digestive enzyme activity of three loaches according to claim 1, wherein the analytical study is carried out by the following steps: firstly, pretreating a sample by adopting a hydrochloric acid hydrolysis method, and then, measuring by using a Hitachi L-8900 amino acid analyzer; determination of fatty acid content the samples were first saponified and then analysed on an Agilent 7890A gas chromatograph.

5. The analytical study on muscle nutrient content and digestive enzyme activity of three loaches according to claim 1, wherein the analytical study is carried out by the following steps: the kit adopted in the determination of the tissue digestive enzyme is purchased from Nanjing to build a bioengineering institute, the model of the kit used by the protease is A080-2-2, the model of the kit used by the lipase is A054-2-1, and the model of the kit used by the amylase is C016-1-1.

6. The analytical study on muscle nutrient content and digestive enzyme activity of three loaches according to claim 1, wherein the analytical study is carried out by the following steps: in the determination of the tissue digestive enzyme, the activity of trypsin is defined as that the enzyme activity unit is obtained by changing the absorbance by 0.003 per minute by trypsin contained in each milligram of protein under the conditions of pH8.0 and 37 ℃; lipase activity units are defined as 1 enzyme activity unit per 1. mu. mol substrate consumed, per mg of tissue protein reacted with the substrate in the present reaction system at 37 ℃ for 1 min; the amylase activity unit is defined as 1 enzyme activity unit for each mg of protein in the tissue to react with the substrate at 37 ℃ for 30min, and hydrolyzing 10mg of starch.

Technical Field

The invention relates to an analytical study on muscle nutrient content and digestive enzyme activity of loaches, in particular to an analytical study on muscle nutrient content and digestive enzyme activity of three loaches, and belongs to the field of application of aquatic organisms.

Background

Loaches (A. anguillicaudatus)Misgurnus anguillicaudatus) And Paramisgurnus dabryanus (Paramisgurnus dabryanus)Paramisgurnus dabryanus) Belonging to the order of Cyprinus carpioides (Cypriniformes) Loach family: (Cobitidae) Respectively belonging to the genus loach (Misgurnus) And Paramisgurnus (Selaginella)Paramisgurnus). Loaches are widely distributed in fresh water areas all over the country, and paramisgurnus dabryanus is mainly distributed in the middle and lower reaches of the Yangtze river and accessory water bodies of the Yangtze river. The two kinds of loaches are similar in appearance, have delicious meat quality and rich nutrition, and are high-quality freshwater aquaculture species. The species background of Taiwan loaches is not clear at all, and the Taiwan loaches are presumed to be a genetically improved population of the Paramisgurnus dabryanus, and the growth speed and the disease resistance of the Taiwan loaches are remarkably superior to those of loaches and Paramisgurnus dabryanus, so that the Taiwan loaches become popular loaches to be cultured in recent years. At present, research on loaches and paramisgurnus dabryanus mainly focuses on artificial breeding, breeding technology, age and growth, the research on the nutrient components of the loaches, the paramisgurnus dabryanus and the Taiwan loaches is less, and the research on the activity of digestive enzymes of the three loaches is blank.

Disclosure of Invention

The invention aims to solve the problems and provide analysis and research on muscle nutrient components and digestive enzyme activity of three loaches.

The invention realizes the purpose through the following technical scheme, and the analytical research on the muscle nutrient content and the digestive enzyme activity of three loaches comprises the following steps:

a. selection of test materials

Randomly selecting 30 loaches (MA), Paramisgurnus Dabryanus (PD) and Taiwan loach (TW) which are strong in physique and have no damage to body surfaces, and preparing for dissection;

b. sample processing

Anaesthetizing the fish body by adopting MS-222 before dissecting the fish body, taking muscles on two sides of the back of the fish body after anaesthetizing, wiping the muscles by using filter paper, mashing the muscles and uniformly mixing the muscles to prepare a sample, averagely dividing the sample into two parts, wherein one part is used for measuring conventional nutrient components, and the other part is placed in a refrigerator for freezing and storing at the temperature of 20 ℃ below zero, and is used for measuring amino acid and fatty acid after freezing and drying;

c. evaluation of muscle nutritional quality

Assessment of muscle nutritional value the Amino Acid Score (AAS), Chemical Score (CS) and Essential Amino Acid Index (EAAI) were calculated according to the following formulas, respectively, based on the amino acid score standard pattern (%, dry) and the amino acid pattern of whole egg protein (%, dry) recommended by FAO/WHO in 1973:

in the formula: aa is the amino acid content (%) of the test sample; AA (FAO/WHO) is the content (%) of the same amino acid in a FAO/WHO scoring standard mode; AA (egg) is the content (%) of the same amino acid in the whole egg protein; n is the number of essential amino acids to be compared; a, B, C, …, H is the essential amino acid content (%, dry) of the sample muscle protein; AE, BE, CE, …, HE is the essential amino acid content (%, dry) of whole egg proteins;

d. determination of tissue digestive enzymes

In the sample processing process, 6 loaches of each loach are respectively narcotized by MS-222 and placed on an ice tray, an intestinal tract and a liver and pancreas are dissected and taken out, food and excrement in the intestinal tract are removed, intestinal wall fat is removed, and the loaches are stored in a refrigerator at the temperature of minus 20 ℃ for freezing and standby after being washed by deionized water; the activity of protease, lipase and amylase in the intestinal tract and the liver and pancreas is measured by adopting a kit;

e. the measured test data were biometrically measured using the SPSS17.0 software, and descriptive statistics were expressed using mean ± standard error (mean ± SD).

Preferably, the test material is taken from an aquaculture farm in Linyi city, and the specifications of the three loaches are that the loaches have the body mass of (18.94 +/-0.73) g and the body length of (13.57 +/-0.59) cm; the mass of the Paramisgurnus dabryanus is (17.35 +/-0.39) g, and the body length is (13.02 +/-0.40) cm; the body mass of the Taiwan loach is (20.17 +/-0.89) g, and the body length is (12.63 +/-0.70) cm.

Preferably, the determination of the conventional nutrient components comprises the determination of moisture, ash, crude protein and crude fat, wherein the moisture determination refers to GB5009.3-2010, and is determined by adopting a drying and water loss method at 105 ℃ and using a BGZ-246 electric heating constant temperature air drying oven; ash content is determined by a dry ashing method at 550 ℃ and a Thermo BF51794JC-1 muffle furnace according to GB/T5009.4-2010; the crude protein is determined by a FOSS 8400 full-automatic azotometer by adopting a trace Kjeldahl azotometer according to GB/T5009.5-2010; the crude fat is determined by a BUCHI E-812 full-automatic Soxhlet fat extractor according to GB/T5009.6-2008.

Preferably, the amino acid in the muscle is measured by firstly pretreating a sample by a hydrochloric acid hydrolysis method and then measuring by using a Hitachi L-8900 amino acid analyzer; determination of fatty acid content the samples were first saponified and then analysed on an Agilent 7890A gas chromatograph.

Preferably, the kit adopted in the determination of the tissue digestive enzyme is purchased from Nanjing institute of bioengineering, the model of the kit used for the protease is A080-2-2, the model of the kit used for the lipase is A054-2-1, and the model of the kit used for the amylase is C016-1-1.

Preferably, in the determination of the tissue digesting enzyme, the activity of trypsin is defined as that one enzyme activity unit is obtained by changing the absorbance by 0.003 per minute per milligram of trypsin contained in the protein at 37 ℃ under the condition of pH8.0; lipase activity units are defined as 1 enzyme activity unit per 1. mu. mol substrate consumed, per mg of tissue protein reacted with the substrate in the present reaction system at 37 ℃ for 1 min; the amylase activity unit is defined as 1 enzyme activity unit for each mg of protein in the tissue to react with the substrate at 37 ℃ for 30min, and hydrolyzing 10mg of starch.

The invention has the beneficial effects that:

1. the invention carries out analysis and research on the nutrient content and the digestive enzyme activity of the three groups of the loaches, the paramisgurnus dabryanus and the Taiwan loaches, aims to enrich the nutrition physiology knowledge of the loaches and provides data reference for the development and the utilization of the nutritional value of the loaches;

2. after the conventional nutrient content of the three loaches is measured, the crude fat content of the three loaches is higher than 3.5%, which shows that the muscles of the three loaches have good flavor and mouthfeel; the crude protein content of loach (MA) is 18.15%, the Paramisgurnus Dabryanus (PD) is 17.45%, and the loach (TW) of Taiwan is 17.10%, which belong to high-protein fishes; the three loach essential amino acids with the highest content are lysine, except Met + Cys, AAS is close to or more than 1, CS is more than 0.5, according to the prediction of AAS and CS, the three loach limiting amino acids are Met + Cys, and the immunity of the organism can be improved after long-term eating;

3. after fatty acid measurement is carried out on three kinds of loaches, 19 kinds of fatty acids including 7 kinds of Saturated Fatty Acids (SFA), 4 kinds of monounsaturated fatty acids (MUFA) and 8 kinds of polyunsaturated fatty acids (PUFA) are detected in the muscles of the three kinds of loaches, and the polyunsaturated fatty acids (PUFA) have the effects of reducing blood pressure, cholesterol and triglyceride and platelet aggregation and also have certain influences on prevention of cardiovascular diseases, anti-tumor and immune regulation, so that the body immunity can be improved and the occurrence probability of diseases can be reduced by frequently eating the loaches.

Drawings

FIG. 1 is a comparison graph of activities of hepatopancreas and intestinal proteases of three loaches.

FIG. 2 is a comparison graph of activities of liver, pancreas and intestinal lipase of three loaches.

FIG. 3 is a comparison graph of the activities of the liver, pancreas and intestinal amylase of three loaches.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The analytical research on the muscle nutrient content and the digestive enzyme activity of three loaches comprises the following steps of:

a. selection of test materials

The test materials are taken from aquaculture farms in the near-Yi city, and 30 loaches (MA), loaches (PD) and Taiwan loaches (TW) which are strong in physique and have no damage to body surfaces are randomly selected, wherein the specifications of the three kinds of loaches are that the loaches have the body mass of (18.94 +/-0.73) g and the body length of (13.57 +/-0.59) cm; the mass of the Paramisgurnus dabryanus is (17.35 +/-0.39) g, and the body length is (13.02 +/-0.40) cm; the body mass of the Taiwan loach is (20.17 +/-0.89) g, and the body length is (12.63 +/-0.70) cm;

b. sample processing

Anaesthetizing the fish body by adopting MS-222 before dissecting the fish body, taking muscles on two sides of the back of the fish body after anaesthetizing, wiping the muscles by using filter paper, mashing the muscles and uniformly mixing the muscles to prepare a sample, averagely dividing the sample into two parts, wherein one part is used for measuring conventional nutrient components, and the other part is placed in a refrigerator for freezing and storing at the temperature of 20 ℃ below zero, and is used for measuring amino acid and fatty acid after freezing and drying;

in addition, in the sample processing process, 6 loaches of each loach are anesthetized by MS-222 and placed on an ice tray, the intestinal tract and the liver and pancreas are dissected and taken out, food and excrement in the intestinal tract are removed, intestinal wall fat is removed, and the loach is stored in a refrigerator at the temperature of-20 ℃ for freezing and standby after being washed by deionized water; the activity of protease, lipase and amylase in the intestinal tract and the liver and pancreas is measured by adopting the kit.

In this test, the measured test data were subjected to biological statistics using SPSS17.0 software, and descriptive statistics were expressed using mean ± standard error (mean ± SD).

EXAMPLE measurement of conventional Nutrition ingredients

The measurement of conventional nutritional ingredients includes the measurement of moisture, ash, crude protein and crude fat.

The moisture determination refers to GB5009.3-2010, adopts a drying and water loss method at 105 ℃, and is performed by using a BGZ-246 electric heating constant temperature air blast drying box;

ash content is determined by a dry ashing method at 550 ℃ and a Thermo BF51794JC-1 muffle furnace according to GB/T5009.4-2010;

the crude protein is determined by a FOSS 8400 full-automatic azotometer by adopting a trace Kjeldahl azotometer according to GB/T5009.5-2010;

the crude fat is determined by a BUCHI E-812 full-automatic Soxhlet fat extractor according to GB/T5009.6-2008.

The contents of water, crude protein, crude fat and ash in the muscle of three loaches are shown in table 1. The crude protein content of loach (MA) is obviously higher than that of Paramisgurnus Dabryanus (PD) and Paramisgurnus dabryanus (TW) ((MA))P<0.05) While the crude fat content is significantly lower than that of the other two loaches: (P<0.05) Loach (MA) has higher water and ash contents than Paramisgurnus Dabryanus (PD) and Taiwan loach (TW), but the difference is not significant (P>0.05)。

TABLE 1 comparison of muscle composition of three loaches

Note: the difference of the lower case letters on the same row of shoulder marks is significant (P<0.05)。

Fat is not a taste-imparting substance per se, but fat can improve the tenderness and rich flavor of fish meat, and is accompanied by some flavor coexisting with fatty acid. Research shows that the fish has good taste when the content of crude fat in the muscle of the fish is 3.5-4.5%. The crude fat content of Taiwan loach (TW) (4.21%) and Paramisgurnus Dabryanus (PD) (4.03%) measured by the test is higher than that of loach (MA) (3.62%), and the crude fat content of three kinds of loaches is higher than 3.5%, which indicates that the three kinds of loach muscles have good flavor and taste.

Protein is an important nutritional component of muscle, and the content and the type of the protein are important indexes for determining the muscle quality of fish. The evaluation of the protein value is determined by factors such as crude protein content, amino acid types and proportion. Since the human body cannot synthesize essential amino acids or the synthesis rate cannot meet the needs of the body, it must rely on the supply of food proteins. Thus, in food productsProteins whose essential amino acid types and proportions correspond to the amino acid composition required by the human body can be called high-nutritional value proteins. The crude protein content of loach (MA) is 18.15%, which is higher than that of Paramisgurnus Dabryanus (PD) by 17.45%, and that of Taiwan loach (TW) by 17.10%, and the crude protein content of three kinds of loaches is higher than that of grass carp(s) (MA)Ctenopharyngodon idellus) Bighead carp, bighead carpHypophthalmichthys nobilis) Yellow catfish (yellow catfish)Pelteobagrus fulvidraco) And salmon (Oncorhynchus keta) The method shows that the three kinds of loaches all belong to high-protein high-quality economic fishes, and have higher economic benefits in popularization and culture.

EXAMPLES measurement of amino acid content in muscle protein and evaluation of amino acid composition

Measurement of amino acids in muscle the samples after freeze-drying were first pretreated by hydrochloric acid hydrolysis, and then measured using a Hitachi L-8900 amino acid analyzer.

Assessment of muscle nutritional value the Amino Acid Score (AAS), Chemical Score (CS) and Essential Amino Acid Index (EAAI) were calculated according to the following formulas, respectively, based on the amino acid score standard pattern (%, dry) and the amino acid pattern of whole egg protein (%, dry) recommended by FAO/WHO in 1973:

in the formula: aa is the amino acid content (%) of the test sample; AA (FAO/WHO) is the content (%) of the same amino acid in a FAO/WHO scoring standard mode; AA (egg) is the content (%) of the same amino acid in the whole egg protein; n is the number of essential amino acids to be compared; a, B, C, …, H is the essential amino acid content (%, dry) of the sample muscle protein; AE, BE, CE, …, HE is the essential amino acid content (%, dry) of whole egg proteins;

as shown in table 2, 17 amino acids were detected in total in the muscle of three kinds of loaches (tryptophan was not detected to have a broken structure by acid hydrolysis), including 7 Essential Amino Acids (EAA), 2 semi-essential amino acids (HEAA) and 8 nonessential amino acids (NEAA). The three loaches with the highest amino acid content are glutamic acid (Glu) and aspartic acid (Asp) in the second place. MudThe amino acid with the lowest content in the loaches (MA) is cystine (Cys), and the methionine (Met) content in the Paramisgurnus Dabryanus (PD) and the Taiwan loaches (TW) is the lowest. The difference of 12 amino acids in three loaches is obvious (P<0.05) The total amount of essential amino acids, non-essential amino acids and flavor amino acids of Misgurni Anguillicaudati (MA) is significantly higher than that of other two Misgurni Anguillicaudati: (MA)P<0.05) The total amount of non-essential amino acids and delicious amino acids of the Paramisgurnus Dabryanus (PD) is obviously higher than that of the paramisgurnus dabryanus (TW) ((PD) in Taiwan)P<0.05)。

TABLE 2 muscle amino acid content of three kinds of loaches

Note: is an essential amino acid; # is umami amino acid; the difference of the lower case letters on the same row of shoulder marks is significant (P<0.05)。

The nutritional value of muscle protein is mainly determined by the type, amount and composition ratio of essential amino acids. The results of EAA Amino Acid Score (AAS) and Chemical Score (CS) are shown in Table 3, the most abundant essential amino acids of the three loaches are lysine, except Met + Cys, AAS is close to or more than 1, and CS is more than 0.5. According to the prediction of AAS and CS, the three loach limiting amino acids are Met + Cys. The essential amino acid index EAAI of Misgurni Anguillicaudati (MA) is 89.59, which is higher than that of Misgurni Anguillicaudati (TW) (83.97) and Paramisgurnus Dabryi (PD) (80.95).

TABLE 3 evaluation of essential amino acid composition in muscle of three loaches

And comparing the nutritional values of three loach proteins, wherein the total amino acid amount, the essential amino acid content, the ratio of essential amino acid to non-essential amino acid and the EAAI of the loaches are highest, the number of the loaches in Taiwan is the second, and the number of the loaches in Scale (PD) is lowest.

The three loach amino acids have complete varieties, and the essential amino acids include lysine, threonine, leucine and isoleucineThe contents of the amino acid, the phenylalanine and the tyrosine are rich, the AAS is more than 1, and the CS is more than 0.5, so that the deficiency of the lysine in the cereal food can be compensated, the utilization of protein by organisms is promoted, the immunity of the organisms is improved, and the hormone level of the human bodies is adjusted. The freshness degree of animal protein is related to the content of delicious amino acid in muscle, and the more the proportion of the delicious amino acid is, the more delicious the food taste is. The proportion of the umami amino acids in the three loaches to the total amino acids is 42.63-42.84%, which is higher than that of the grass carp (A), (B), (C), (B) and (C)Ctenopharyngodon idellus) Yellow catfish (yellow catfish)Pelteobagrus fulvidraco) Red tilapia mossambica (Red tilapia Oreochromis spp.)。

The Essential Amino Acid Index (EAAI) is a common indicator for assessing the nutritional value of body proteins. The EAAI of the three loaches is 80.95-89.59, the index of essential amino acid is higher than that of the goby fish (the giant salamander)Glossogobius giuris) Sturgeon, sturgeon (A) and (B)Acipenser schrencki) Salmon (a)Oncorhynchus keta) Mandarin rice (Mandarin rice)Siniperca chuatsi) The three kinds of loaches are high-quality economic fishes which are rich in high-quality protein and can provide fresh water rich in essential amino acid.

EXAMPLE determination of fatty acid content in muscle

Determination of fatty acid content the samples were first saponified and then analysed on an Agilent 7890A gas chromatograph.

The results of fatty acid detection in the muscle of three kinds of loaches are shown in table 4, and a total of 19 kinds of fatty acids including 7 kinds of Saturated Fatty Acids (SFA), 4 kinds of monounsaturated fatty acids (MUFA) and 8 kinds of polyunsaturated fatty acids (PUFA) were detected in the muscle sample of loach. The saturated fatty acid contents of the three loaches are respectively 24.56%, 22.29% and 23.36, and the saturated fatty acid content of the Paramisgurnus Dabryanus (PD) is lower than that of the other two loaches (I), (II)P>0.05). The content of unsaturated fatty acid is 45.17%, 48.60% and 48.65%, respectively, and the unsaturated fatty acid in loach (MA) is significantly lower than that in other two kinds of loaches (MA)P<0.05) Wherein the content of monounsaturated fatty acid in muscle of loach (MA) is 15.49%, which is significantly lower than that of other two kinds of loaches (A)P<0.05) The muscle polyunsaturated fatty acid content of the loach (MA) is 29.68 percent and is obviously higher than that of the other two loaches (MA)P<0.05). Loach (MA)The content of EPA and DHA in the muscle is 9.24 percent, which is obviously higher than that of Taiwan loach (TW) (7.23 percent) and loach Paramisgurnus Dabryanus (PD) (4.74 percent)P<0.05). The n-3 group and n-6 group unsaturated fatty acids in the muscle of the three kinds of loaches have the highest loach (MA) contentP<0.05)。

TABLE 4 muscle fatty acid content of three kinds of loaches

Note: the difference of the lower case letters on the same row of shoulder marks is significant (P<0.05)。

The unsaturated fatty acid content of loach (MA) is highest (29.68%) and is significantly higher than that of Paramisgurnus Dabryanus (PD) (24.32%) and Misgurnus Taiwanensis (TW) (16.59%). In this experiment, the EPA + DHA content in loach (MA), Paramisgurnus Dabryanus (PD) and taiwan loach (TW) was 9.24%, 4.74% and 7.23%, respectively.

Fatty acids are important factors for the growth and survival of organisms, and 19 fatty acids including 7 Saturated Fatty Acids (SFA), 4 monounsaturated fatty acids (MUFA) and 8 polyunsaturated fatty acids (PUFA) are detected in the muscles of three loaches. Polyunsaturated fatty acid (PUFA) has effects in lowering blood pressure, reducing cholesterol and triglyceride, reducing platelet aggregation, preventing cardiovascular diseases, resisting tumor, and regulating immunity. EPA and DHA are polyunsaturated fatty acids mainly existing in fish fat and are essential fatty acids for the growth and development of human bodies, so that the three kinds of loaches can provide unsaturated fatty acids required by human bodies and can improve the immunity of the human bodies after being eaten frequently.

EXAMPLES assay of four tissue digestive enzymes

In this example, the kit used for the determination of tissue digestive enzymes was purchased from Nanjing institute of bioengineering, the kit model used for protease was A080-2-2, the kit model used for lipase was A054-2-1, and the kit model used for amylase was C016-1-1.

In the sample processing process, 6 loaches of each loach are respectively narcotized by MS-222 and placed on an ice tray, an intestinal tract and a liver and pancreas are dissected and taken out, food and excrement in the intestinal tract are removed, intestinal wall fat is removed, and the loaches are stored in a refrigerator at the temperature of minus 20 ℃ for freezing and standby after being washed by deionized water; the activity of protease, lipase and amylase in the intestinal tract and the liver and pancreas is measured by adopting the kit.

The activities of protease, lipase and amylase in the liver, pancreas and intestinal tract of three loaches are shown in figures 1 to 3. The activities of protease and lipase in intestinal tracts of three loaches are obviously higher than that of hepatopancreas, and the activity of amylase is obviously lower than that of hepatopancreas (A)P<0.05). The activity of protease in liver, pancreas and intestinal tract of loach (MA) is significantly higher than that of other two loaches (MA)P<0.05) The protease activity of the Paramisgurnus Dabryanus (PD) is higher than that of paramisgurnus dabryanus (TW) ((TW))P>0.05). The lipase activity in intestinal tracts of Paramisgurnus Dabryanus (PD) and Taiwan loach (TW) is obviously higher than that of loach (MA), (D), (TW)P<0.05) The liver and pancreas lipase activity of Taiwan loach (TW) is obviously higher than that of other two kinds of loaches (TW)P<0.05). The amylase activity of liver, pancreas and intestinal tract of loach (MA) is obviously higher than that of Paramisgurnus Dabryanus (PD) and Taiwan loach (TW) (MA)P<0.05)。

Digestive enzyme is a protein which is secreted by digestive glands and digestive system and used for catalyzing biochemical reaction of organisms, and the absorption and utilization of nutrient substances by fish bodies are directly influenced by the activity of the digestive enzyme. The determination of the activities of the three loach digestive enzymes can reflect the growth speed, the digestive absorption and the feed utilization difference of organisms to a certain extent, and provides experimental basis for the selection of feeds in the production and breeding processes.

As can be seen from the figures 1 to 3, in the feeding process of the three loaches, the digestion and absorption capacity of the intestinal tract to protein and fat is higher than that of starch, so that in the feed formula, 15 to 50 percent of starch source feed can be replaced by protein source raw materials and fat source raw materials, the absorption and utilization of energy in the feed by fish bodies are enhanced, and the feed conversion rate is improved.

In conclusion, the crude fat contents of the Taiwan loach (TW) and the Paramisgurnus Dabryanus (PD) in the three loaches disclosed by the invention are respectively 4.21 percent and 4.03 percent and are higher than 3.62 percent of that of loach (MA),the crude fat content of the three loaches is higher than 3.5%, which shows that the muscles of the three loaches have good flavor and taste; the crude protein content is higher than that of grass carp (A)Ctenopharyngodon idellus) Bighead carp, bighead carpHypophthalmichthys nobilis) Yellow catfish (yellow catfish)Pelteobagrus fulvidraco) And salmon (Oncorhynchus keta) Wherein the loach (MA) crude protein content is 18.15%, the Paramisgurnus Dabryanus (PD) is 17.45%, and the Taiwan loach (TW) is 17.10%, which belong to high protein fishes; the three loach essential amino acids with the highest content are lysine, except Met + Cys, AAS is close to or more than 1, CS is more than 0.5, according to the prediction of AAS and CS, the three loach limiting amino acids are Met + Cys, and the immunity of the organism can be improved after long-term eating; the proportion of the umami amino acids in the three loaches to the total amino acids is 42.63-42.84%, which is higher than that of the grass carp (A), (B), (C), (B) and (C)Ctenopharyngodon idellus) Yellow catfish (yellow catfish)Pelteobagrus fulvidraco) Red tilapia mossambica (Red tilapia Oreochromis spp.) The taste and flavor are excellent; the EAAI of the three loaches is 80.95-89.59, the index of essential amino acid is higher than that of the goby fish (the giant salamander)Glossogobius giuris) Sturgeon, sturgeon (A) and (B)Acipenser schrencki) Salmon (a)Oncorhynchus keta) Mandarin rice (Mandarin rice)Siniperca chuatsi) The three kinds of loaches are high-quality economic fishes which are rich in high-quality protein and can provide fresh water rich in essential amino acid; the muscle of three kinds of loaches is detected with 19 kinds of fatty acids, including 7 kinds of Saturated Fatty Acids (SFA), 4 kinds of monounsaturated fatty acids (MUFA) and 8 kinds of polyunsaturated fatty acids (PUFA), and the polyunsaturated fatty acids (PUFA) have the functions of lowering blood pressure, reducing cholesterol and triglyceride and reducing platelet aggregation, and also have certain effects on preventing cardiovascular diseases, resisting tumors and regulating immunity, so the body immunity can be improved and the occurrence probability of diseases can be reduced by eating the loaches frequently.

Therefore, the loach is a fish with high nutrition, and has high economic benefit when popularized and cultured.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.