CN110623165A - Aquaculture feed and preparation method thereof - Google Patents

Abstract

The invention discloses a preparation method of aquaculture feed, which comprises the steps of feeding fly maggots by kitchen organic solid waste added with Shewanella putrefaciens, inducing the fly maggots to generate a specific antibacterial function on the Shewanella putrefaciens, and preparing the fly maggots into the aquaculture feed. The aquaculture feed prepared by the invention has an antibacterial effect and can improve the immunity of aquaculture objects to Shewanella putrefaciens.

Description

Aquaculture feed and preparation method thereof

Technical Field

The invention relates to an aquaculture feed and a preparation method thereof.

Background

At present, the prevention and treatment of aquatic animal bacterial diseases in China mainly adopts a method of combining oral antibiotics with a disinfectant splashed in a whole pool, but the use of the antibiotics can cause the cultured objects to generate drug resistance and form drug accumulation in vivo, thereby influencing the quality of aquatic products; the disinfectant can inhibit and kill plankton in water, inhibit photosynthesis of aquatic plants, cause water body anoxia, destroy water body ecological balance, and influence growth of cultured objects.

If the aquaculture feed can improve the immunity of river crabs to Shewanella putrefaciens, a new way can be provided for preventing Shewanella putrefaciens infection of aquaculture objects.

Disclosure of Invention

The invention aims to provide an aquaculture feed and a preparation method thereof, the aquaculture feed has an antibacterial effect and can improve the immunity of aquaculture objects to Shewanella putrefaciens.

In order to realize the aim, the invention provides a preparation method of aquaculture feed, which is characterized in that kitchen organic solid waste added with Shewanella putrefaciens is used for feeding fly maggots, the fly maggots are induced to generate a specific antibacterial function on the Shewanella putrefaciens, and then the fly maggots are prepared into the aquaculture feed.

Preferably, the preparation method of the aquaculture feed comprises the following steps:

1) uniformly spreading and drying the fly larvae on the surface of the kitchen organic solid waste, and culturing the fly larvae for 4-5 days;

the feeding amount of the kitchen organic solid waste is 65-85 kg/m²(ii) a Adding a bacterium solution containing Shewanella putrefaciens into the kitchen organic solid waste, and adding 100ml of the bacterium solution into each kilogram of the kitchen organic solid waste and uniformly stirring; the content of Shewanella putrefaciens in the bacterial liquid is 9 × 10⁹cfu/mL；

And (3) breeding density of fly maggots: 1-10 g of fly maggot larvae are thrown into each kilogram of kitchen organic solid waste;

the fly maggot breeding environment: the temperature is controlled to be 25-26 ℃, the air humidity is 65%, the sunlight is prevented from irradiating, and ventilation is kept;

2) collecting mature fly larvae into a clean container, and placing for 4-6 hours to fully discharge food in the fly larvae to obtain fresh fly larvae;

3) cleaning fresh maggots and then placing the cleaned fresh maggots into a drying oven for drying: the temperature in the oven is 40-45 ℃, the drying time is 10-12 hours, and the stir-frying is carried out once every 30 minutes;

4) crushing the dried dry maggots into dry maggot powder;

5) and uniformly mixing the crushed dry maggot powder with auxiliary materials to prepare the aquaculture feed.

The invention also provides an aquaculture feed prepared by the preparation method.

Preferably, the aquaculture feed is for feeding river crabs.

The invention has the advantages and beneficial effects that: the aquaculture feed has antibacterial effect by applying Shewanella putrefaciens, and can improve immunity of aquaculture objects to Shewanella putrefaciens.

Detailed Description

The following further describes embodiments of the present invention with reference to examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The invention provides an aquaculture feed which is prepared from functional housefly larvae induced by Shewanella putrefaction, and comprises the following steps:

1) uniformly spreading and drying the fly larvae on the surface of the kitchen organic solid waste, and culturing the fly larvae for 4-5 days;

the feeding amount of the kitchen organic solid waste is 65-85 kg/m²(ii) a Adding a bacterium solution containing Shewanella putrefaciens into the kitchen organic solid waste, and adding 100ml of the bacterium solution into each kilogram of the kitchen organic solid waste and uniformly stirring; the content of Shewanella putrefaciens in the bacterial liquid is 9 × 10⁹cfu/mL；

And (3) breeding density of fly maggots: 1-10 g of fly maggot larvae are thrown into each kilogram of kitchen organic solid waste;

the fly maggot breeding environment: the temperature is controlled to be 25-26 ℃, the air humidity is 65%, the sunlight is prevented from irradiating, and ventilation is kept;

2) collecting mature fly larvae into a clean container, and placing for 4-6 hours to fully discharge food in the fly larvae to obtain fresh fly larvae;

3) cleaning fresh maggots and then placing the cleaned fresh maggots into a drying oven for drying: the temperature in the oven is 40-45 ℃, the drying time is 10-12 hours, and the stir-frying is carried out once every 30 minutes;

4) crushing the dried dry maggots into dry maggot powder;

5) and uniformly mixing the crushed dry maggot powder with auxiliary materials to prepare the aquaculture feed.

The aquaculture feed prepared by the invention has an antibacterial effect, can be used for feeding river crabs, and can improve the immunity of the river crabs to Shewanella putrefaciens.

The comparative tests were as follows:

preparing a bacterial liquid: inoculating Shewanella putrefaciens pure culture in nutrient broth, performing shake culture at 28 deg.C for 24 hr at 100r/min, centrifuging, and concocting with physiological saline by turbidimeter to obtain Shewanella putrefaciens with bacteria content of 9 × 10⁹cfu/ml bacterial solution (mother solution), and according to the test requirements, diluting the bacterial solution into bacterial solutions with different concentrations by using physiological saline, and storing the bacterial solutions at 4 ℃ for later use.

Culturing fly maggots: adding 2000g of kitchen organic solid waste into a plastic plate, and adding bacterial liquid (the content of Shewanella putrefaciens in the bacterial liquid is 9 multiplied by 10)⁹cfu/mL) 200mL, stirring evenly, then putting 20g of newly hatched housefly larvae (1.2 mg/fly larvae), maintaining the room temperature at 25-26 ℃ by an air conditioner, keeping the air humidity at 65%, and culturing for 4 days to obtain mature housefly larvae, namely functional housefly larvae induced by the isolate.

Challenge test a:

the initial screening of the proper infection dose of Shewanella putrefaciens to the river crabs (the average weight is 62 g/crab) is firstly carried out, the approximate range of the infection dose is determined, and then the formal challenge test A is started. In No. 1-4 water tank (length × width × height =60cm × 40cm × 30cm, water depth 10 cm), 10 river crabs are respectively put in, and the bacterial liquid concentration is 2 × 10 respectively after the number of the water tank is infected in sequence⁸、1×10⁸、0.5×10⁸、0.25×10⁸cfu/mL, 0.1mL is injected into each river crab muscle, and the bacterial infection doses of the No. 1-4 boxed river crabs are respectively: 0.40X 10⁵、0.81×10⁵、1.61×10⁵、3.23×10⁵cfu/g, the day and night oxygenation is kept during the test period, the room temperature of the air conditioner is maintained at 27-28 ℃, and the test result is observed and recorded after 48 hours. The half-lethal dose of the strain to the river crab for 48h (LD 50) is calculated by adopting a modified kouyama method.

The results of the Shewanella putrefaciens challenge test A on river crabs are shown in Table 1. As can be seen in Table 1, after 48 hours of artificial infection with Shewanella putrefaciens, 3.23X 10⁵The death rate of the river crabs in the cfu/g dose group is 100 percent, and is 0.40 multiplied by 10⁵The mortality rate of the cfu/g dose group of the river crabs is 20 percent. The LD50 of Shewanella putrefaciens for artificial infection of river crab for 48h is calculated to be 0.71 multiplied by 10 by adopting an improved Korotkoff method⁵cfu/g。

TABLE 1 Shewanella putrefaciens challenge test A on river crabs

Challenge test B:

in 4 water tanks 1-4 (length x width x height =60cm x 40cm x 30cm, water depth 10 cm), 10 healthy river crabs are respectively put in, mixed feed and functional fly maggots are fed every day (the ratio of the two is 9: 1), the daily feeding amount is 3 percent of the weight of the river crabs, the river crabs are fed averagely twice every morning and evening (8: 00 and 17: 00), the breeding test is carried out for one week, and then the challenge test B (carried out according to the method of the challenge test A) of the separated bacteria on the experimental river crabs is carried out. Oxygen is added day and night in the whole test period, the room temperature is maintained at 27-28 ℃, and underwater excrement is sucked out every day by an air conditioner.

The result of the toxicity attacking test B of Shewanella putrefaciens on the feeding functional fly maggot river crabs is shown in the table 2. By improving the Korea method, the LD50 of Shewanella putrefaciens for artificially infecting river crabs with functional fly maggots for 48 hours is calculated to be 2.29 multiplied by 10⁵cfu/g of the strain is (0.71 multiplied by 10) of the strain in the challenge test A of functional fly maggot and river crab not fed⁵cfu/g) 3.2 times.

TABLE 2 Shewanella putrefaciens challenge test on feeding functional fly maggot river crab

And (4) conclusion: the results of the challenge test A and the challenge test B show that the 48h LD50 of Shewanella putrefaciens on the functional fly maggot river crabs fed with the induced functional fly maggot is 2.29 multiplied by 10⁵cfu/g is 3.2 times of that of the river crabs without feeding functional fly maggots, which shows that the immunity of the river crabs to the Shewanella putrefaction can be obviously improved by adding the functional fly maggots into the compound feed.

Claims (4)

1. The preparation method of the aquaculture feed is characterized in that kitchen organic solid waste added with Shewanella putrefaction is used for feeding fly maggots, the fly maggots are induced to generate a specific antibacterial function on the Shewanella putrefaction, and then the fly maggots are prepared into the aquaculture feed.

2. A method of preparing an aquaculture feed according to claim 1 comprising the steps of:

1) uniformly spreading and drying the fly larvae on the surface of the kitchen organic solid waste, and culturing the fly larvae for 4-5 days;

the feeding amount of the kitchen organic solid waste is 65-85 kg/m²(ii) a Adding a bacterium solution containing Shewanella putrefaciens into the kitchen organic solid waste, and adding 100ml of the bacterium solution into each kilogram of the kitchen organic solid waste and uniformly stirring; the content of Shewanella putrefaciens in the bacterial liquid is 9 × 10⁹cfu/mL；

And (3) breeding density of fly maggots: 1-10 g of fly maggot larvae are thrown into each kilogram of kitchen organic solid waste;

the fly maggot breeding environment: the temperature is controlled to be 25-26 ℃, the air humidity is 65%, the sunlight is prevented from irradiating, and ventilation is kept;

2) collecting mature fly larvae into a clean container, and placing for 4-6 hours to fully discharge food in the fly larvae to obtain fresh fly larvae;

3) cleaning fresh maggots and then placing the cleaned fresh maggots into a drying oven for drying: the temperature in the oven is 40-45 ℃, the drying time is 10-12 hours, and the stir-frying is carried out once every 30 minutes;

4) crushing the dried dry maggots into dry maggot powder;

5) and uniformly mixing the crushed dry maggot powder with auxiliary materials to prepare the aquaculture feed.

3. An aquaculture feed produced by the method of claim 1 or 2.

4. An aquaculture feed according to claim 3 for raising river crabs.