CN102429109B - Methionine oligopeptide and application thereof in prawn feed - Google Patents

Abstract

The invention relates to a methionine oligopeptide, which is a mixture of methionine dipeptide to octapeptide, and the methionine oligopeptide is used as an additive for prawn feed. In the present invention, the methionine oligopeptide is used as an additive in the prawn feed, and the addition amount is only 0.1% to 0.2%, which can promote the growth of the prawn, improve the utilization of the plant protein source by the prawn, and reduce the usage amount of fish meal in the feed, thereby playing a role The role of reducing feed costs. And the methionine oligopeptide can improve the synchronous absorption of the methionine released from the methionine oligopeptide and the protein-bound methionine in the feed without affecting the pH of the feed; Dissolution and loss characteristics in aquaculture water environment. As a substitute product of crystalline amino acid, the invention can supplement the lack of methionine in plant protein sources, thereby improving the utilization rate of prawns to plant protein sources. It has better effect when applied together with the bait formulated in the present invention.

Description

A kind of methionine oligopeptide and its application in shrimp feed

technical field

The invention belongs to the technical field of aquatic feed, and in particular relates to an additive that can be used for prawn feed, in particular to a methionine oligopeptide for prawn and its application technology.

Background technique

In recent years, with the increase of aquaculture production in our country year by year, the production of aquatic feed is far from meeting the demand of the market. At present, the market space of my country's aquatic feed is more than 10 million tons. While increasing the production of aquatic feed, it is also necessary to consider how to reduce the cost of feed in order to obtain the greatest economic benefits. Protein is the main nutrient in feed and a key factor in determining the cost of feed. Most aquaculture animals require high protein content in the feed, and at the same time rely particularly on the animal protein source - fishmeal, which greatly increases the cost of aquaculture animal feed. In particular, fishmeal will always be a resource that is increasingly in short supply worldwide. Therefore, people try to use relatively cheap vegetable protein to partially or completely replace animal protein, so as to prepare feed for aquaculture animals, so as to reduce costs and improve economic benefits. However, many studies have shown that plant protein can only replace animal protein in a small amount in feed, and raising animals with such feed often causes problems such as reduced food intake, reduced conversion rate, slow growth, and abnormal changes in body composition. One of the important reasons is that the amino acid composition of plant protein is unbalanced, especially the lack of methionine, which limits the application of plant protein in aquaculture animal feed.

Litopenaeus vannamei (Penaeus vannamei) is a wide-temperature and wide-salt tropical shrimp, which has the characteristics of fast growth and strong disease resistance. It is also very popular in the market. The protein requirement in Litopenaeus vannamei feed reaches 40%, which requires a higher content of fishmeal to be added to the feed. Therefore, replacing expensive fishmeal in feed with plant protein sources is an effective way to reduce feed costs for Litopenaeus vannamei. In research and production, it is hoped that adding methionine to plant protein can make up for the deficiency of plant protein amino acid imbalance. At present, commercial methionine additives are mainly crystalline methionine, including DL-methionine, DL-methionine hydroxyl analog (MHA), DL-methionine hydroxyl analog calcium salt (MHA-Ca) and N-hydroxymethylmethionine calcium. Among them, DL-methionine is the most common. However, most of the crystalline amino acids in the feed have been absorbed by the midgut glands before entering the midgut of prawns, while the combined amino acids enter the midgut after digestion and decomposition, and cannot be absorbed synchronously with the crystalline amino acids. At the same time, the use of crystalline amino acids will change the pH of feed and affect the utilization of feed by aquatic animals. In addition, crystalline amino acids in feed are prone to dissolution and loss in water environment, which reduces the utilization rate of feed. These factors have resulted in the fact that crystalline amino acids have not been widely used in aquafeeds so far. Therefore, it is very important to solve the problems of asynchronous amino acid absorption, feed pH and dissolution loss to promote the application of amino acids in aquafeeds and increase the substitution ratio of plant protein sources to fishmeal.

Contents of the invention

The purpose of the present invention is to provide a methionine oligopeptide and its application in prawn feed, so as to solve the problems of asynchronous amino acid absorption, feed pH and dissolution loss, and make up for the deficiencies in the prior art.

The methionine oligopeptide of the present invention is a mixture of methionine dipeptide to octapeptide.

The methionine oligopeptide of the present invention is synthesized by papain to methionine ethyl ester hydrochloride

The specific preparation method is as follows: make 300 mg/ml of ethyl methionine hydrochloride into a sodium citrate solution with a pH of 5.5, then dissolve papain in cysteine containing 0.1 mol/L and 10 mmol/L ethylene glycol The pH of diethyl ether diamine tetraacetic acid is 6.5 to make papain solution in the aqueous solution, then add the papain solution into the methionine ethyl ester hydrochloric acid solution according to the mass ratio of 1:200, react at 37°C for 2 hours, collect the precipitate , add papain solution to the supernatant according to the mass ratio of 1:200, and react overnight at 37°C; after the reaction, dilute the product with distilled water and heat to 90°C to inactivate the protease; The methionine oligopeptide of the present invention is obtained by washing in three times and freeze-drying the product.

The application of the above-mentioned methionine oligopeptide as an additive in aquatic feed.

Wherein said aquatic feed is prawn feed, and the addition amount of methionine oligopeptide is 0.1%-0.2%.

The above-mentioned prawn feed is preferably the feed of the following formula, and its components and mass percentages are as follows: 8-12% of fish meal, 4-6% of shrimp shell powder, 25-28% of flour, 4-8% of squid viscera powder, 26-30% of soybean meal %, peanut meal 14-18%, fish oil 2-4%, soybean lecithin 0.8-1.4%, shelling protein 0.05-0.15%, choline chloride 0.2-0.4%, antioxidant 0.04-0.06%, antifungal agent 0.05-0.15%, calcium dihydrogen phosphate 0.36-0.38%, vitamin and mineral premix for prawns 2-4%.

In the present invention, the methionine oligopeptide is used as an additive in the prawn feed, and the addition amount is only 0.1% to 0.2%, which can promote the growth of prawns, improve the utilization of plant protein sources by prawns, and reduce the use of fish meal in the feed, thereby playing a role The role of reducing feed costs. And the methionine oligopeptide of the present invention can improve the synchronous absorption of the methionine released from the methionine oligopeptide and the protein-bound methionine in the feed without affecting the pH of the feed; It has the characteristics that it is not easy to dissolve and lose in the aquaculture water environment. As a substitute product of crystalline amino acid, the invention is added to prawn feed to supplement the lack of methionine in plant protein sources, thereby improving the utilization of prawns to plant protein sources and reducing feed costs. It has better effect when applied together with the feed formulated by the invention.

Instructions attached

Figure 1: Mass spectra for determining the molecular weight of peptides with different degrees of polymerization in methionine oligopeptides.

Detailed ways

Embodiment 1: the preparation of methionine oligopeptide

The methionine oligopeptide of the present invention can be artificially synthesized or prepared by a biological enzymatic method; the biological preparation method is described below:

Make methionine ethyl ester hydrochloride into 300mg/ml sodium citrate solution with a pH of 5.5, then dissolve papain in cysteine containing 0.1mol/L and 10mmol/L ethylene glycol diethyl ether diamine tetra The pH of acetic acid is 6.5 in aqueous solution to make papain solution, then add papain solution into methionine ethyl ester hydrochloric acid solution according to the mass ratio of 1:200, and react at 37°C for 2 hours, after collecting the precipitate, put it in the supernatant Then add papain solution at a mass ratio of 1:200 and react overnight at 37°C; after the reaction, dilute the product with distilled water and heat to 90°C to inactivate the protease; wash the water-insoluble matter three times in distilled water and freeze The dried product is the methionine oligopeptide of the present invention.

Embodiment 2: the detection of the prepared methionine oligopeptide

The molecular weights of peptides with different degrees of polymerization in methionine oligopeptides were determined by mass spectrometry (technical support provided by Beijing Emino Medical Co., Ltd.). , 7-peptide and 8-peptide mixture.

Embodiment 3: the application of methionine oligopeptide

Fish meal, shrimp shell powder, flour, squid viscera powder, soybean meal, peanut meal, fish oil, soybean lecithin, shelling factor, choline chloride, antioxidant, antifungal agent, calcium dihydrogen phosphate, vitamins and minerals for prawns The premix is the main raw material, and three kinds of artificial compound feeds for prawns are prepared (see Table 1 for details): Feed 1# is a feed prepared according to a commercial formula (control group), which is a high-fish meal group; feed 2# is low-fish meal and added crystals Methionine treatment group; Feed 3# is a treatment group with low fish meal and added methionine oligopeptide of the present invention.

Table 1: Experimental Feed Formula

The same batch of Litopenaeus vannamei, weighing about 0.62 g, was selected as the experimental shrimp. After one week of domestication, the prawns with strong physique and uniform size were selected for group test. It is divided into 3 groups, each group has 3 parallels, and each parallel is a 250L glass fiber reinforced plastic bucket, stocking 30 Litopenaeus vannamei for the test, and the 3 groups are fed with 1#, 2# and 3# test feeds respectively . Change the water once a day, the water change volume is 3/4 of the total volume, and inflate. During the 50-day breeding test, the dissolved oxygen in seawater was 7.8-8.2 mg/L, pH 7.5-8.0, salinity 30-32, and temperature 27-31°C. They were fed four times a day, at 06:00, 12:00, 18:00, and 24:00, respectively. They were fed with enough food, and the residual bait and excrement were removed every day.

At the beginning and end of the experiment, each parallel Litopenaeus vannamei was counted and weighed, and the survival rate, weight gain rate, specific growth rate and feed factor of Litopenaeus vannamei were calculated.

Survival rate = N _t /N ₀ ×100

Weight gain = (W _t -W ₀ )/W ₀ ×100

Specific growth rate = (LnW _t -LnW ₀ )×100/t

Feed coefficient = W _d / (W _t -W ₀ )

Among them, N ₀ and N _t are the initial and final tail numbers of each parallel Litopenaeus vannamei, respectively, W ₀ and W _t are the initial body weight and final body weight of each parallel Litopenaeus vannamei, respectively, and W _d is the feed for the shrimp Dry weight (g), t is the number of days of the experiment.

Finally, SPSS 13.0 for Windows was used to conduct one-way analysis of variance on the measurement data of the above indicators. The experimental results are represented by mean ± standard error (mean ± S.E.), and different English superscript letters in the upper right corner of the same row indicate significant differences (P<0.05).

The specific experimental results are shown in Table 2.

Table 2: Effects of feeding methionine oligopeptides on the survival, growth and feed coefficient of Litopenaeus vannamei

The dissolution loss rate of the present invention is reduced by more than 10% compared with the existing added forms. Adding this methionine oligopeptide in low fishmeal diet can improve the growth of Litopenaeus vannamei and reduce the feed coefficient of Litopenaeus vannamei compared with adding crystalline methionine. It can be seen that a very small amount of methionine oligopeptide can improve the growth of prawns, thereby improving the utilization of plant protein sources by prawns.

In order to obtain a better breeding effect, according to the characteristics of prawns, the following ratio of feed is formulated: fish meal 8-12%, shrimp shell powder 4-6%, flour 25-28%, squid viscera powder 4-8%, soybean meal 26% -30%, peanut meal 14-18%, fish oil 2-4%, soybean lecithin 0.8-1.4%, shelling protein 0.05-0.15%, choline chloride 0.2-0.4%, antioxidant 0.04-0.06%, anti-oxidant Mold agent 0.05-0.15%, calcium dihydrogen phosphate 0.36-0.38%, shrimp vitamin and mineral premix 2-4%. Among them, fish meal, shrimp shell powder, flour, squid viscera powder, soybean meal, peanut meal, fish oil, soybean lecithin, shelling factor, choline chloride, antioxidant, antifungal agent, calcium dihydrogen phosphate and vitamins and minerals for prawns The premix can be selected from any commercially available components for prawn bait, fish meal of the present invention, shrimp shell powder, flour, squid viscera powder, soybean meal, peanut meal, fish oil, soybean lecithin, shelling factor, chlorinated Choline, antioxidants, antifungal agents and calcium dihydrogen phosphate were provided by Qingdao Qihao Biotechnology Co., Ltd. The vitamin and mineral premix for prawns can be selected from the premix described in the Chinese published patent CN 1875747. In the embodiment of the present invention, the vitamin and mineral premix special for prawns from Hewitt prawns produced by Jinhaili Aquatic Technology Co., Ltd. material.

The oligopeptide of the present invention is added to the prepared feed by 0.2% by mass. Compared with the currently used methionine crystal methionine feed which is also added by 0.2% by mass, the prepared feed of the present invention not only improves immunity and disease resistance There is an improvement, and the growth rate of Litopenaeus vannamei also increases by 10-15%. Compared with the commercial feed, the feed formulated by the invention increases the growth rate of the prawns by 3-5%, and reduces the feed cost by more than 10%.

Claims (1)

1. methionine oligopeptide application in aquatic feeds as additive, described methionine oligopeptide is that methionylmethionine is to the mixture of octapeptide, with papain, the methionine carbethoxy hydrochloride is synthesized preparation, its concrete preparation method is as follows: the pH that the methionine carbethoxy hydrochloride is made into 300 mg/ml is 5.5 sodium citrate solution, the pH that again papain is dissolved in the cysteine that contains 0.1 mol/L and 10 mmol/L ethylene glycol diethyl ether ethylenediamine tetraacetic acid (EDTA)s makes papain solution in 6.5 the aqueous solution, then papain solution is joined in methionine ethyl ester solution according to mass ratio 1:200, under 37 ℃ of conditions, reaction is 2 hours, after collecting precipitation, in supernatant more in mass ratio 1:200 add papain solution, react under 37 ℃ of conditions and spend the night, after reaction finishes, use the distilled water diluting product, and be heated to 90 ℃ and come inactivated proteases, water-insoluble is washed in distilled water three times, lyophilisation product namely makes methionine oligopeptide,

Described aquatic feeds is feed for litopenaeus vannamei; And in feed for litopenaeus vannamei, the addition of methionine oligopeptide is 0.1%～0.2%; The recipe ingredient of described prawn feed and mass percent are: fish meal 8-12%, shrimp shell meal 4-6%, flour 25-28%, squid viscera powder 4-8%, dregs of beans 26-30%, peanut meal 14-18%, fish oil 2-4%, soybean lecithin 0.8-1.4%, the plain 0.05-0.15% that shells, Choline Chloride 0.2-0.4%, antioxidant 0.04-0.06%, mould inhibitor 0.05-0.15%, calcium dihydrogen phosphate 0.36-0.38%, prawn vitamin and minerals premix 2-4%.

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