CN113598286B - Application of glutamine in improving growth performance of rainbow trout - Google Patents

Abstract

The invention discloses an application of glutamine in improving the growth performance of rainbow trout, wherein the glutamine is used as a growth promoter for feeding the rainbow trout, and the effect of the glutamine on the growth performance of the rainbow trout is researched, and the method comprises the following steps: muscle growth ability, protein synthesis and degradation ability, digestive ability of intestinal tract, lipid metabolism ability of liver, etc. Researches find that the glutamine has the functions of promoting the muscle growth of the rainbow trout, inhibiting the protein degradation, promoting the intestinal digestion, enhancing the lipid metabolism in the liver, reducing the lipid deposition in the liver and the like, and the glutamine can obviously improve the growth rate and the feed utilization rate of the rainbow trout. Therefore, the glutamine can be used as a growth promoter for improving the production performance of the rainbow trout, promoting the rapid growth of the rainbow trout and ensuring the health of fish bodies, and has important significance for breeding the rainbow trout and improving the yield of the rainbow trout.

Description

Application of Glutamine in Improving Growth Performance of Rainbow Trout

technical field

The invention belongs to the technical field of fish growth promoters, and in particular relates to the application of glutamine in improving the growth performance of rainbow trout.

Background technique

Rainbow trout (scientific name: Oncorhynchus mykiss) is a kind of salmon in the family Salmonidae and the genus Pacific Salmon. The side of the body is like a rainbow because of the wide longitudinal band-shaped red stripes, so it is named rainbow trout. It is native to the Pacific coast of North America and the Kamchatka Peninsula. . Rainbow trout is a fish with high economic value. Its meat is fresh and tender, delicious, without fishy smell, especially small bone spurs, and there is no need to scrape the scales when eating. Rainbow trout meat is rich in unsaturated fatty acids and amino acids, which is conducive to human body absorption and nutritional balance. Among them, unsaturated fatty acids can prevent and treat cardiovascular diseases, and are also essential nutrients for the development of the brain, retina, and nervous system, and play an important role in the brain development of fetuses and young children. At the same time, unsaturated fatty acids can effectively resist chronic diseases and diabetes. In addition, rainbow trout contain DHA and EPA, which are called "brain gold", which are much higher than other fish, and have good medicinal and edible value , can reduce the concentration of cholesterol in the blood, prevent cardiovascular diseases caused by arteriosclerosis, reduce inflammation, prevent cancer from spreading, and improve brain function. Rainbow trout also contains high amounts of B vitamins, especially vitamin B12, and small amounts of vitamin D, vitamin A, and vitamin E. In addition, rainbow trout meat contains trace elements that play an important role in human metabolism, such as selenium, iodine, and fluorine.

Amino acids are the components of proteins in tissues and cells. Some amino acids can be synthesized endogenously by the body itself, while others can only be obtained from diet. Amino acids participate in many important metabolic and immune pathways, and are involved in cell survival, maintenance and proliferation. play a pivotal role. Among many amino acids, glutamine (Gln) is the most versatile and abundant amino acid in animals. It is crucial in body metabolism, acid-base balance, and protein synthesis. In almost all cells, Gln can be used as a nucleoside Substrates for acids (purines, pyrimidines, and amino sugars), nicotinamide adenine dinucleotide phosphate (NADPH), antioxidant synthesis, and many biosynthetic pathways involved in maintaining cellular integrity and function.

Contents of the invention

The object of the present invention is to provide the application of glutamine in improving the growth performance of rainbow trout. The present invention finds through research that glutamine has the functions of promoting muscle growth of rainbow trout, inhibiting protein degradation, promoting intestinal digestion and enhancing lipid metabolism in the liver. , reduce liver lipid deposition and other effects, and glutamine can significantly improve the growth rate and feed utilization of rainbow trout. Therefore, it can be used as a growth promoter to improve the production performance of rainbow trout and promote the growth of rainbow trout, and has extremely high production and application value.

To achieve the above object, the technical solution adopted in the present invention is:

The invention provides the application of glutamine in improving the growth performance of rainbow trout.

Further, the indicators of growth performance include: muscle growth ability, protein synthesis and degradation ability, intestinal digestion ability and liver lipid metabolism ability.

Further, the glutamine promotes muscle growth of rainbow trout.

Further, the glutamine down-regulates muscle growth by up-regulating the expression of myocyte enhancer factor 2A, myocyte enhancer factor 2C, fructose 1-6 bisphosphatase, myogenic determinant factor 5, myogenin, and myogenic differentiation antigen The expression of inhibin 2 can promote the muscle growth of rainbow trout.

Further, the glutamine inhibits protein degradation of rainbow trout.

Further, the glutamine inhibits the protein degradation of rainbow trout by down-regulating the expression of apoptosis-related protease Caspase3, muscle breakdown factor cathepsin D, calpain1 and ubiquitin-L, and up-regulating the expression of calpain inhibitor protein CAST .

Further, the glutamine promotes the digestive ability of rainbow trout intestine.

Further, the glutamine promotes lipid catabolism in rainbow trout liver.

The invention also provides the application of glutamine in improving the feed utilization rate of rainbow trout.

The invention also provides a growth promoter for rainbow trout, which includes glutamine.

Compared with the prior art, the beneficial effect of the present invention is: the present invention uses glutamine as a growth promoter for feeding rainbow trout, explores the effect of glutamine on the growth performance of rainbow trout, including: muscle growth ability, protein synthesis and degradation ability, intestinal digestion ability, liver lipid metabolism ability, etc. Studies have found that glutamine can promote muscle growth in rainbow trout, inhibit protein degradation, promote intestinal digestion, enhance lipid metabolism in the liver, and reduce liver lipid deposition, etc., and glutamine can significantly improve the growth rate and feed utilization of rainbow trout Rate. Therefore, glutamine can be used as a growth promoter to improve the production performance of rainbow trout, promote the rapid growth of rainbow trout, and ensure the health of fish body. It is of great significance for rainbow trout breeding to increase the yield of rainbow trout.

Description of drawings

Fig. 1 is the detection result of the expression level of genes related to muscle growth in Example 1 of the present invention;

Figure 2 is the detection result of the expression level of genes related to protein degradation in Example 1 of the present invention;

Fig. 3 is the staining of paraffin sections of intestinal tissue in Example 1 of the present invention and the statistical results of the aspect ratio of intestinal villi and the number of goblet cells;

Fig. 4 is the detection result of the activity of each digestive enzyme in the intestinal tract in Example 1 of the present invention;

Fig. 5 is the detection result of the concentration of TC, HDL, LDL, AST and ALT in the liver and serum in Example 1 of the present invention;

Fig. 6 shows the staining of liver tissue morphology, the relative mRNA expression levels of genes related to lipid synthesis and decomposition in the liver, and the detection results of TG concentrations in the liver and serum in Example 1 of the present invention.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1 Exploration of Glutamine's Effects on the Growth Performance of Rainbow Trout

1. Test material

Rainbow trout (30.0±2.0g) with consistent size and health were cultured in running water with mountain spring water in Shangnan Fishing Farm, Shiyan City, Hubei Province. They were raised in cylinders with a diameter of 55 cm and a height of 50 cm, and were divided into two groups: the control group and the Gln group, with 3 tanks for each group and 25 fish in each tank. They were fed three times a day in the morning, noon and evening, and the control group was fed normally. For rainbow trout feed, the Gln group was supplemented with 1% Gln in addition to the normal rainbow trout feed. After 4 weeks of continuous feeding, 8 tails were randomly selected from each tank for sampling. Dissolved oxygen is tested every day, and water quality indicators such as ammonia nitrogen are tested every other day.

2. Effects of glutamine on muscle growth and protein degradation in rainbow trout

In order to study the effect of glutamine treatment on muscle growth and protein degradation of rainbow trout, the real-time fluorescent quantitative PCR method was used to analyze the expression changes of genes related to muscle growth, protein synthesis and degradation, and the specific experimental steps were as follows:

(1) Extraction of total RNA

1) Take out the tissue sample from the -80°C refrigerator, put it into a 2mL RNAiso Plus centrifuge tube with 1mL TRIzol reagent, add DEPC water to treat the sterilized glass beads, homogenize in a homogenizer for 1min and observe the tissue in TRIzol Whether it has been broken completely, then immediately stand at 4°C for 10 minutes.

2) Add 0.2 mL of chloroform, shake the centrifuge tube vigorously for 10 seconds, let stand at 4°C for 5 minutes, and then centrifuge at 12000 r/min at 4°C for 15 minutes.

3) Carefully pipette the supernatant into a new 1.5mL RNAiso Plus centrifuge tube, add an equal volume of isopropanol, turn it upside down gently several times to fully react the isopropanol with the supernatant, and let stand at 4°C for 10 minutes Then centrifuge at 12000r/min at 4°C for 10min.

4) Discard the supernatant, add 1 mL of 75% ethanol prepared from DEPC water, re-spin the precipitate, and centrifuge at 7500 r/min at 4°C for 5 min.

5) Discard the supernatant, repeat step 4) and put it in the fume hood to dry on ice for about 10 minutes, until the 75% ethanol in the centrifuge tube is completely evaporated, add an appropriate amount of DEPC water to dissolve the precipitate, and gently use a pipette if necessary Dissolve the pellet completely by pipetting.

6) Detection of RNA purity and concentration: DEPC water was used as a blank control, and 1 μL of RNA was taken in an ultramicro spectrophotometer to measure the concentration of the RNA sample and the ratio of OD ₂₆₀ /OD ₂₈₀ . When the absorbance ratio is between 1.9-2.1, it indicates that the extracted total RNA is of high purity without protein or genome contamination.

7) Detection of RNA integrity: Take 2 μL RNA, mix with 1 μL loading buffer, electrophoresis on 1% agarose gel, voltage 140V, after 18 min, observe the result in the gel imaging system. The 28S and 18S bands are clear, and the brightness ratio is about 2:1. If the 5S band is looming, and there are no other bands, it means that the extracted total RNA has good integrity and can be used in the next reverse transcription experiment.

(2) Synthesis of cDNA:

1) Removal of genomic DNA:

The abm reverse transcription kit was used, and the operation was carried out according to the instructions of the kit.

Reverse transcription system I includes:

Add the reagents according to the above system, vortex, mix and centrifuge, place in the PCR instrument at 42°C for 2 minutes, and place the product on ice after completion.

2) Reverse transcription reaction:

Prepare cDNA reverse transcription reagents, reverse cDNA, and the reaction system is shown in the table below:

The reagents were added sequentially and then shaken and centrifuged. The reaction conditions were: 25°C for 10 minutes, 42°C for 90 minutes (the reverse transcription time was selected according to the quality of RNA), and 85°C for 5 minutes. Reverse transcription was completed in a 20 μL system. After measuring the concentration of cDNA, it was diluted to the same concentration with deionized water and stored at -20°C.

(3) Primer design

The genes related to muscle generation and protein degradation in the rainbow trout genome were found in NCBI, and the genes related to muscle generation include: myogenic differentiation antigen (MyoD), myostatin 1 (Myostain1), myostatin 2 (Myostain2), myogenin, fructose 1-6 bisphosphatase (FBP), myogenic determinant 5 (MYf5), myocyte enhancer factor 2A, 2C (MEF2A/2C); genes associated with protein degradation Including: proteasome 20D (Prot 20D), apoptosis-related protease Caspase3, calpain1, calpain inhibitor CAST, muscle breakdown factor cathepsin D and ubiquitin-L.

Further determine the open reading frame region of the above-mentioned gene, and use the gene sequence of this region to design gene primers (three pairs for each gene) in Primer Premier 5.0 software according to the conventional methods in this field. Synthesized and purified by Wuhan Synthesis Department of Xinye Biotechnology Co., Ltd. Then detect by conventional PCR technology, each pair of primers determines three suitable temperature gradients for PCR, and then detects the PCR products by agarose gel electrophoresis, selects samples with single and bright bands in the three temperatures and sends them to the company for further analysis sequencing. If the comparison results are consistent, it indicates that the primers are good and can be used in subsequent experiments. In this way, suitable primers and optimal annealing temperature were screened. The conventional PCR amplification system is:

The PCR reaction conditions were: pre-denaturation at 95°C for 5 min; denaturation at 95°C for 30 s; annealing at 55°C for 30 s; extension at 72°C for 1 min; extension at 72°C for 10 min. The denaturing annealing extension was carried out for 30 cycles.

(4) Real-time fluorescent quantitative PCR

480系统进行。分别用定量引物和内参引物扩增目的基因片段，以β-Actin基因的表达量作为校准，qRT-PCR反应体系如下：qRT-PCR reaction in Roche

480 system is carried out. Quantitative primers and internal reference primers were used to amplify target gene fragments, and the expression level of β-Actin gene was used as calibration. The qRT-PCR reaction system was as follows:

According to the reaction system, mix the corresponding reagents evenly and add them into a light-proof 96-well plate, seal the film, and centrifuge in a low-speed centrifuge for 10 seconds. The qRT-PCR reaction was performed in a Roche LightCycler 480 fluorescence quantitative PCR instrument. The reaction conditions were as follows: pre-denaturation at 95°C for 10 minutes, denaturation at 95°C for 10 seconds, and annealing at 57°C for 10 seconds. A total of 40 cycles were added, and a melting curve was added. Three samples were set for each sample. repeat.

After qRT-PCR, analyze the melting curve to ensure the specificity of the reaction. EF-1α was used as an internal reference gene, and the relative quantitative data was analyzed by the 2 ^-ΔΔCt method. GraphPad Prism 6 was used to analyze qRT-PCR data. The data represent at least three independent experiments (mean ± standard error), using Student's t-test for data analysis, where P<0.05 is indicated by *, representing a significant difference; P<0.01 is indicated by **, P<0.001 Indicated by ***, all represent extremely significant differences.

(5) Results and analysis

The expression of genes related to muscle growth is shown in Figure 1, and the expression of genes related to protein degradation is shown in Figure 2. The results showed that after Gln treatment, the expression of myogenic factor 2A, 2C (MEF2A/2C), fructose 1-6 bisphosphatase (FBP) was significantly up-regulated; myogenic determinant 5 (MYf5), muscle The original protein (Myogenin) and myogenic differentiation antigen (MyoD) also showed an upward trend; at the same time, the expression of myostatin 2 (Myostain2) decreased significantly, but the expression of myostatin 1 (Myostain1) had no difference. Among the factors related to protein degradation, the expression of apoptosis-related protease Caspase3 and muscle breakdown factor cathepsin D decreased significantly; the expression of calpain (Calpain1) and ubiquitin (Ubiquitin-L) showed a downward trend; There was no difference in the expression of ; however, the expression of calpain inhibitor (CAST) was significantly upregulated. This result indicates that Gln can promote muscle formation in rainbow trout while inhibiting protein degradation.

3. Effect of glutamine on intestinal digestion ability of rainbow trout

The paraffin sections of intestinal tissue were stained and observed for rainbow trout in the Gln group and the control group, and the main digestive enzymes in the intestinal tract were detected, including lipase, α-amylase, trypsin and chymotrypsin. The specific experimental steps are as follows:

(1) Production of intestinal tissue paraffin sections

1) Material collection: MS-222 anesthetized experimental fish, took the gill tissue of the control group and Gln group fish, and carefully picked it up with tweezers to avoid damaging the tissue.

2) Fixation: Put the taken tissue into 4% paraformaldehyde tissue fixative, make the fixative fully immerse the tissue, put the fixed tissue into a 4° C. refrigerator or room temperature for fixation.

3) Gradient dehydration: 60% absolute ethanol 4h, 70% absolute ethanol overnight (8-10h), 80% absolute ethanol 2h, 90% absolute ethanol 2h, 95% absolute ethanol I1.5h, 95% anhydrous ethanol Water ethanol II 1h, 100% absolute ethanol I 0.5h, 100% absolute ethanol II 0.5h.

4) Transparent: benzyl alcohol solution for 10 minutes, xylene I for 7 minutes, and xylene II for 7 minutes.

5) Dip in wax: Dip in paraffin wax at 60°C for 3 times, change the cylinder each time, and each time for 1 hour.

6) Embedding: Put the wax-soaked embedding frame into the melted embedding machine, carefully take out the tissue with tweezers, immerse it on the embedding table, and inject melted paraffin into the complete metal embedding frame , and then put the tissue on the embedding table into the central position of the metal embedding frame in turn according to the appropriate section required for the experiment, wait for the wax block to solidify, and store the wax block at room temperature.

7) Slicing: Trim the cut surface of the wax block according to the needs of the experiment, and then fix it on the microtome until the desired tissue section is cut. The thickness of the slice is 5 μm, and put it into the slicer. The water temperature of the slicer is 41°C Left and right, the cut surface in the slicer is no longer wrinkled, and the slices can be picked up. Then the slides were placed in a constant temperature oven at 65°C for 2h. Store the treated slides in a 4°C refrigerator.

(2) Alcian blue staining (AB) staining steps

1) Put the slides to be stained in a constant temperature oven at 65°C for 5-10min.

2) Dewaxing: Xylene I 20min, Xylene II 15min, Xylene III 15min.

3) Xylene was replaced: absolute ethanol I for 5 min, absolute ethanol II for 5 min, and 75% absolute ethanol for 5 min. Wash with water for 3 minutes.

4) Shake off the water on the slide as much as possible, circle the tissue parts of the slide with a histochemical pen, and stain with Alcian blue (shake evenly before use) staining solution to ensure that each tissue is covered with the staining solution, and use a pipette The liquid gun blows and mixes, and the dyeing time is 20-25min.

5) Rinse off the dye solution with water, then soak in water for 3 minutes.

6) Shake off the water, dye the tissue with nuclear fast red (shake evenly before use) staining solution, blow and beat to mix evenly, and the staining time is 10 minutes. Rinse off the dye with water, soak in water for 3 minutes;.

7) Slides were transferred to 85% ethanol for 5 minutes, 95% ethanol for 5 minutes, 100% ethanol for dehydration for 15 minutes, n-butanol for 5 minutes, xylene I for 5 minutes, and xylene II for 5 minutes.

8) Mount the slide with neutral gum.

9) Imaging: Images were acquired in a microscope (Olympus) using AXIOVISION software.

(3) Hematoxylin-eosin staining (HE) staining step

1) Put the slides to be stained in a constant temperature oven at 65°C for 5-10min.

2) Dewaxing: Xylene I 20min, Xylene II 15min, Xylene III 15min.

3) Xylene was replaced: absolute ethanol I for 5 min, absolute ethanol II for 5 min, and 75% absolute ethanol for 5 min. Wash with water for 3 minutes.

4) Stain with hematoxylin for 3 minutes (the time can be adjusted according to the effect of the hematoxylin dye solution), wash twice with water, and then soak in water for 3 minutes.

5) After washing, immerse the slide in differentiation solution (99mL 70% alcohol + 1mL concentrated HCl) for 3-5s, wash in water for 5s, wipe off the water and then examine under the microscope. If the staining is deep, continue to wash in water for a period of time to fully remove HCL. If the differentiation is not complete, it can be soaked in the differentiation solution again.

6) After rinsing, immerse in the blue-returning solution (99mL 70% alcohol + 1mL concentrated ammonia water) for 3-5s, take it out, rinse it under distilled water, and then transfer it to distilled water for 3 minutes.

7) The slides were placed in 85% ethanol for 5 minutes, 95% ethanol for 5 minutes, and dipped in eosin solution (1 g of water-soluble eosin dissolved in 100 mL of 85% alcohol) for 2-3 minutes. If staining is difficult, 1-2 drops of glacial acetic acid can be added to every 100mL of staining, which can make the tissue easy to stain and not easy to decolorize.

8) Gradient alcohol dehydration: absolute ethanol I for 5 min, absolute ethanol II for 5 min, absolute ethanol III for 5 min, and n-butanol for 5 min.

9) Xylene I 5min, xylene II 5min.

10) Mount the slide with neutral gum.

11) Imaging: Images were acquired in a microscope (Olympus) using AXIOVISION software.

12) Count and analyze the length-to-width ratio of intestinal villi and the number of goblet cells.

(4) Determination of enzyme activity

The rainbow trout in the control group and the Gln group were taken, and intestinal tissues were taken, and the activities of major digestive enzymes in the intestine were measured by lipase, α-amylase, trypsin and chymotrypsin kits (purchased from Nanjing Jiancheng Biological Company), including : Lipase, α-amylase, trypsin and chymotrypsin. Student’s t-test was used for data analysis, where P<0.05 is represented by *, representing a significant difference; P<0.01 is represented by **, and P<0.001 is represented by ***, all representing extremely significant differences.

(5) Results and analysis

The detection results are shown in Figure 3 and Figure 4, in which Figure 3-(a) is the HE and AB staining images of intestinal tissue paraffin sections of the control group and Gln group (scale bar: 50 μm); Figure 3-(b) is the intestinal The statistical results of the length-to-width ratio of intestinal villi and the number of goblet cells in the intestinal tract tissue; Figure 4 shows the results of the activity determination of various digestive enzymes in the intestinal tract.

The results showed that compared with the control group, the length-to-width ratio of the intestinal villi in the Gln group was significantly increased, and the number of goblet cells (per intestinal villi) was significantly reduced, indicating that Gln promotes the growth of intestinal villi, which is beneficial to the absorption of nutrients, and in the intestinal tract The activity of lipase increased significantly, while the activities of α-amylase, trypsin and chymotrypsin had no significant difference, which indicated that Gln promoted the digestive ability of rainbow trout intestine.

4. Effect of glutamine on liver lipid metabolism of rainbow trout

(1) In order to explore the effect of glutamine on the liver lipid metabolism of rainbow trout, the liver and serum of the control group and the Gln group were collected respectively, and the TC (total cholesterol ), HDL (high-density lipoprotein cholesterol), LDL (low-density lipoprotein cholesterol), AST (aspartate aminotransferase) and ALT (alanine aminotransferase) concentrations, the measurement results are shown in Figure 5.

The results showed that the evaluation of the liver health status showed that the TC concentration and LDL concentration in the Gln group in the liver were significantly reduced, and the HDL concentration was not different; LDL concentrations did not differ. For the other two important indicators for evaluating liver damage, AST and ALT, the concentrations in the Gln group were significantly lower in both liver and serum. Thus, Gln has a protective effect on the liver.

(2) According to the above method, the liver tissue morphology was observed by HE staining, and the detection results were shown in Figure 6-(a), and the relative mRNA expression of lipid synthesis and decomposition related genes in the liver was further measured by conventional qRT-PCR method levels, including: lipid synthesis-related sterol regulatory element-binding protein 1 (Srebp-1), acetyl-CoA carboxylase α (ACCα), fatty acid synthase (FAS), fatty acid dehydrogenase (Fads2), stearin Acyl-CoA desaturase (Scd); low-density lipoprotein cholesterol (LPL) associated with lipolysis, carnitine palmitoyltransferase 1α (Cpt1α), and peroxisome proliferator-activated receptor α (PPARα) Isogenes, and the TG (triglyceride) content in the liver and serum of different treatment groups was measured using a kit (purchased from Nanjing Jiancheng Biology Co., Ltd.), and the detection results are shown in Figure 6-(b).

The results showed that according to HE staining, the white fat particles in the liver of the Gln group were reduced, and the quantitative results showed that the expression of Srebp-1, ACCα, FAS, and Fads2 genes related to lipid synthesis were significantly down-regulated, and the expression of Scd was also down-regulated. trend; while the expression of LPL related to lipolysis was down-regulated, and the expressions of Cpt1α and PPARα were significantly up-regulated. Correspondingly, the content of TG in the liver of the Gln group was significantly reduced, but there was no difference in the content of TG in the serum. The above results indicated that Gln enhanced the catabolism of lipids in the liver and reduced the lipid deposition in the liver.

5. Effects of glutamine on growth rate, weight gain rate and feed conversion rate of rainbow trout

The final body weight of rainbow trout in the control group and the Gln group were counted separately, and the specific growth rate, weight gain rate and feed conversion rate were calculated. in:

Specific growth rate (SGR,%/day): 100×ln[final weight (g)-initial weight (g)]/culture days Weight gain rate (%): (final weight-initial weight)/initial weight

Feed conversion rate (%): Feeding amount (g)/weight gain (g)

The data represents at least three independent experiments (mean ± standard error), using Student's t-test for data analysis, and calculating the P value, the results are shown in the following table:

The results showed that after Gln treatment, the final body weight, specific growth rate and weight gain rate of rainbow trout were significantly increased compared with the control group, while the feed conversion rate was significantly reduced. The above results indicated that Gln improved the growth performance of fish and Therefore, it can be made into a growth promoter to promote the rapid growth of rainbow trout and increase the yield.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims (1)

1. The application of glutamine in preparing the feed additive for improving the growth performance of the rainbow trout is characterized in that the glutamine is added into the feed of the rainbow trout, the addition amount of the glutamine is 1%, the initial weight of the rainbow trout is 30 +/-2.0 g, and the indexes of the growth performance comprise: muscle growth capacity, protein degradation capacity, digestive capacity of the gut, and liver lipid metabolism capacity;

the glutamine promotes the muscle growth of the rainbow trout, and the expression of myostatin 2 is reduced by up-regulating the expression of myocyte enhancing factor 2A, myocyte enhancing factor 2C, fructose 1-6 bisphosphatase, myogenic determining factor 5, myogenic protein and myogenic differentiation antigen, so that the muscle growth of the rainbow trout is promoted;

the glutamine inhibits the protein degradation of the rainbow trout, and the glutamine can inhibit the protein degradation of the rainbow trout by down-regulating the expression of apoptosis-related protease Caspase3, muscle decomposition factor cathepsin D, calpain1 and Ubiquitin-L and up-regulating the expression of Calpain inhibition protein CAST;

the glutamine promotes the digestive capacity of the intestinal tract of the rainbow trout;

the glutamine promotes the catabolism of lipids in the liver of rainbow trout.

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