A composite biological preparation for preventing and treating bacterial diseases in ducks

Abstract

The present invention provides a biological preparation and application for preventing and treating duck bacterial diseases. The strain used is duck-derived plant lactobacillus isolated from duck cecal contents, and the deposit number of the strain is CGMCC No. 26622. The present invention provides a biological preparation and a preparation method for preventing and treating duck bacterial diseases. The prepared composite biological preparation can better adapt to the intestinal environment of ducks and set values, effectively prevent and treat Riemerella anatipestifer disease, Escherichia coli disease, Salmonella, Staphylococcus aureus, Streptococcus and Haemophilus, and can improve the growth and development of meat ducks, increase feed utilization, and improve the quality of duck meat. It is suitable for being widely used as a functional health composite biological preparation, and will play an important role in promoting large-scale antibiotic-free breeding of modern meat ducks.

Description

Technical Field

[0001] The invention belongs to the technical field of animal microecological preparations, and in particular relates to a biological preparation for preventing and treating bacterial diseases in ducks. Background Art

[0002] In the process of modern large-scale duck farming, most of the probiotics used in feed or drinking water have the main targeted functions of promoting growth and development and improving feed conversion rate, but lack specific strains with targeted functions that can effectively inhibit harmful bacteria such as Riemerella anatipestifer, Escherichia coli, Salmonella, and Staphylococcus aureus, resulting in the unsatisfactory effect of microecological agents on the prevention and treatment of bacterial diseases, and the inability to achieve antibiotic-free farming. In current farming practices, when the duck breeding density is high, the sanitary conditions are poor, the ground is damp, the ventilation in the house is poor, and the concentration of harmful gases is high, the incidence of Riemerella anatipestifer and Escherichia coli disease is often high. Considering that the breeding period of meat ducks is only about 35 days, if antibiotics are used when the disease occurs, it will cause veterinary drug residue safety risks; and if drugs are used during the egg-laying period of laying ducks, due to the deposition of yolk fat and the strong lipophilicity of drugs, it is also easy to cause drug residues. For this reason, it is of great practical significance to explore efficient biological agents that inhibit harmful bacteria instead of antibiotics by utilizing the antagonism between probiotics and harmful bacteria. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a biological preparation for preventing and treating duck bacterial diseases, thereby effectively preventing and treating bacterial diseases such as Riemerella anatipestifer, Escherichia coli, Salmonella, Staphylococcus aureus and the like.

[0004] The present invention provides a composite biological preparation, comprising freeze-dried duck-derived Lactobacillus plantarum powder and propyl gallate;

[0005] The Lactobacillus plantarum (LP) was deposited on February 21, 2023 at the General Microbiology Center of the China Culture Collection Administration Committee, Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number CGMCC No. 26622.

[0006] The composite biological preparation, wherein the number of live bacteria in the freeze-dried duck-derived Lactobacillus plantarum powder is 1.5×10 11 CFU / g~4×10 11 CFU / g.

[0007] In the composite biological preparation, the mass ratio of duck-derived plant lactobacillus freeze-dried powder to propyl gallate is 2 to 6:1.

[0008] Preferably, the mass ratio of the duck-derived Lactobacillus plantarum freeze-dried powder to propyl gallate is 4:1.

[0009] The freeze-dried bacterial powder is prepared by adding lactose and skimmed milk powder to a bacterial suspension of duck-derived plant lactobacillus and then adopting vacuum freeze drying.

[0010] The mass ratio of duck-derived Lactobacillus plantarum suspension, lactose and skimmed milk powder is 20:0.5~2:0.5~2.

[0011] Preferably, the mass ratio of the duck-derived Lactobacillus plantarum suspension, lactose and skimmed milk powder is 20:1:1.

[0012] The freeze-dried bacterial powder preparation method is to first pre-freeze at -40°C for 12 hours before vacuum freeze drying, and then place it in a freeze dryer for vacuum freeze drying for 45 to 48 hours.

[0013] The composite biological preparation provided by the present invention can be used as a feed additive to prepare poultry feed. When used in duck compound feed, it can inhibit the reproduction of harmful bacteria, promote body growth and development, and improve slaughter performance and meat quality.

[0014] The present invention separates and obtains a plant lactobacillus from ducks that can effectively inhibit Riemerella anatipestifer, Escherichia coli, Salmonella, Staphylococcus aureus, etc., and then compounds duck-derived plant lactobacillus with propyl gallate to prepare a composite biological preparation to inhibit the growth and reproduction of Riemerella, Escherichia coli, Salmonella, Staphylococcus aureus, etc. The composite biological preparation provided can also promote the growth and development of meat ducks, increase feed conversion rate and improve meat quality; the prepared composite biological preparation makes the pH of feed drop relatively slowly, and can delay the shelf life of feed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : Comparison of the inhibitory effects of kimchi-derived and duck-derived Lactobacillus plantarum fermentation products on the growth of Escherichia coli.

[0016] Figure 2 : Comparison of the inhibitory effects of kimchi-derived and duck-derived Lactobacillus plantarum fermentation products on the growth of Riemerella anatipestifer.

[0017] Figure 3 : Comparison of the effects of duck-derived Lactobacillus plantarum fermentation products and commonly used Lactobacillus plantarum fermentation products in corporate feed on inhibiting the growth of swine-derived Streptococcus S41 strain,

[0018] Figure 4 : Comparison of the effects of duck-derived Lactobacillus plantarum fermentation products and commonly used Lactobacillus plantarum fermentation products in corporate feed on inhibiting the growth of swine-derived Streptococcus 43765 strain,

[0019] Figure 5 : Comparison of the effects of duck-derived Lactobacillus plantarum fermentation products and Lactobacillus plantarum fermentation products commonly used in corporate feed on inhibiting the growth of Haemophilus gallinarum IC strains,

[0020] Figure 6 : Comparison of the effects of duck-derived Lactobacillus plantarum fermentation products and Lactobacillus plantarum fermentation products commonly used in corporate feed on inhibiting the growth of Haemophilus gallinarum Hy strain.

[0021] Figure 7 :The effect of duck-derived Lactobacillus plantarum fermentation products and propyl gallate in inhibiting the growth of Escherichia coli.

[0022] Figure 8 :The effect of duck-derived Lactobacillus plantarum fermentation products combined with propyl gallate on inhibiting the growth of Riemerella anatipestifer.

[0023] Fig. 9 :The effect of duck-derived Lactobacillus plantarum fermentation products combined with propyl gallate on inhibiting the growth of Salmonella.

[0024] Fig.10 :The effect diagram of the combination of duck-derived Lactobacillus plantarum fermentation product and propyl gallate in inhibiting the growth of Staphylococcus aureus. DETAILED DESCRIPTION

[0025] The present invention prepares a biological preparation by combining duck-derived plant lactobacillus with propyl gallate on the basis of selecting duck-derived plant lactobacillus that can effectively inhibit the growth and reproduction of Riemerella, Escherichia coli, Salmonella, Staphylococcus aureus, Streptococcus, and Haemophilus, and can better adapt to the intestinal environment of ducks and determine the value compared with other strains of the same species. Through the composite use of the two, the amount of duck-derived plant lactobacillus added is effectively reduced, and the biological preparation has a more obvious antibacterial effect, and has the functions of promoting growth and development and improving meat quality, etc., providing important technical support for the healthy breeding of ducks in my country.

[0026] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0027] Example 1: Screening of duck-derived Lactobacillus plantarum and its effect in inhibiting harmful bacteria

[0028] (1) Screening of bacterial strains: The cecal contents of 28-day-old Beijing ducks were sterilely collected and inoculated into MRS broth. The culture was activated in a constant temperature shaker (18 h, 35°C). After activation, the bacterial solution was centrifuged (4°C, 10 min, 6000 r / min). After centrifugation, the bacterial sludge was retained and eluted with the same volume of sterile saline. The above centrifugation and elution steps were repeated twice to prepare a bacterial suspension. The bacterial suspension was diluted 10 -3After doubling, 100 μL was spread on a plate containing LPS (Lactobacillus plantarum selective medium) medium and cultured anaerobically inverted for 36 h. A single colony producing a carbon ring was picked out and purified using the four-zone streak method in LPS medium. Streaking and purification were performed continuously for two generations to obtain a purified single colony. The appearance was observed by Gram staining, and the colonies that met the conditions were screened out for 16s identification after biochemical identification experiments to obtain the isolated target strain.

[0029] (2) Inhibition of harmful bacteria:

[0030] Experiment 1: Select kimchi-derived plant lactobacillus (BNCC194165) and screened duck-derived plant lactobacillus, culture them in MRS broth for 18 hours, filter the bacteria, take the supernatant (fermentation product), and mix it with the culture medium containing common duck harmful bacteria (Escherichia coli, Riemerella) in proportion (the ratio of duck-derived plant lactobacillus supernatant to harmful bacteria is 1:4), put them into the microbial growth analyzer (ELISA) and measure the growth curve.

[0031] from Figure 1 , Figure 2 The results of antibacterial assay show that the fermentation products of duck-derived Lactobacillus plantarum have better inhibitory effects on duck harmful bacteria than those of kimchi-derived Lactobacillus plantarum. Figure 1 The results showed that the Escherichia coli in the group supplemented with duck-derived Lactobacillus plantarum fermentation product did not grow for 24 consecutive hours, while the Escherichia coli in the group supplemented with kimchi-derived Lactobacillus plantarum fermentation product showed a growth trend after 10 hours. Figure 2 The results showed that the Riemerella in the group with the addition of duck-derived Lactobacillus plantarum fermentation product did not show a significant growth trend within 24 hours, while the group with the addition of kimchi-derived Lactobacillus plantarum fermentation product showed a significant growth trend compared with the group with the addition of duck-derived Lactobacillus plantarum fermentation product. In summary, the results show that duck-derived Lactobacillus plantarum fermentation product has a better inhibitory effect on duck harmful bacteria than conventional Lactobacillus plantarum fermentation product.

[0032] Experiment 2: Select conventional plant lactobacillus added to the company's feed and duck-derived plant lactobacillus, culture them in MRS broth for 18 hours, filter the bacteria, take the supernatant (fermentation product), and mix it with the culture medium containing swine streptococci and chicken Haemophilus in proportion (the ratio of duck-derived plant lactobacillus supernatant to harmful bacteria is 1:4), put it into the microbial growth analyzer (enzyme reader) and measure the growth curve.

[0033] from Figure 3 , Figure 4 The results of antibacterial tests show that duck-derived Lactobacillus plantarum fermentation products have a significant inhibitory effect on swine-derived Streptococcus, and the effect of duck-derived Lactobacillus plantarum fermentation products is more obvious than the conventional Lactobacillus plantarum preparations added to corporate feed. Figure 3The results showed that the porcine Streptococcus (serotype S41) in the group supplemented with duck-derived Lactobacillus plantarum fermentation products did not show any growth for 36 consecutive hours, while the group supplemented with Lactobacillus plantarum fermentation products commonly used in corporate feed showed a growth trend after 14 hours. Figure 4 The results showed that the porcine streptococci (serotype 43765) in the group with duck-derived Lactobacillus plantarum fermentation products did not show any growth trend within 32 hours, while the porcine streptococci showed a significant growth promotion trend compared with the group with duck-derived Lactobacillus plantarum fermentation products. In summary, the results showed that the inhibitory effect of duck-derived Lactobacillus plantarum fermentation products on porcine streptococci was more significant than that of the plantarum fermentation products commonly used in corporate feed.

[0034] Figure 5 , Figure 6 The results of antibacterial assays showed that duck-derived Lactobacillus plantarum fermentation products had equivalent inhibitory effects on Haemophilus gallinulatus compared with conventional Lactobacillus plantarum fermentation products added to corporate feed. Figure 5 The results showed that Haemophilus gallinaceus (serotype Hbg-IC) did not grow in the group supplemented with duck-derived Lactobacillus plantarum fermentation products and the group supplemented with conventional Lactobacillus plantarum fermentation products added to corporate feed for 18 consecutive hours, while harmful bacteria showed a growth trend in both groups at the 20th hour. Figure 6 The results showed that Haemophilus gallinarum (serotype Hbg-Hy) in the group with added duck-derived Lactobacillus plantarum fermentation products and the group with added conventional Lactobacillus plantarum fermentation products in corporate feed showed no growth trend within 18 hours, and the inhibitory effect of the duck-derived Lactobacillus plantarum fermentation products group was slightly better than that of the conventional Lactobacillus plantarum fermentation products in corporate feed. The above results show that duck-derived Lactobacillus plantarum fermentation products and Lactobacillus plantarum fermentation products commonly used in corporate feed have significant antibacterial effects on Haemophilus gallinarum, and duck-derived Lactobacillus plantarum fermentation products have an advantage in the inhibitory effect on serotype Hbg-IC, while Lactobacillus plantarum fermentation products commonly used in corporate feed have an advantage in the inhibitory effect on serotype Hbg-Hy.

[0035] Example 2: Preparation of composite biological preparations

[0036] (1) Activation of strains: The duck-derived Lactobacillus plantarum strain was inoculated into MRS broth and cultured at 35°C for 24 h. Then, a 1% inoculum was inoculated into MRS broth for enrichment at 35°C for 24 h. The concentration of Lactobacillus plantarum cultured by this method was 1-7×10 9 CFU / mL.

[0037] (2) Preparation of suspension: The bacterial solution was centrifuged at 6000 rpm, 4°C, for 10 min; physiological saline was added for elution, and the above steps were repeated twice to obtain bacterial sludge (1-7×10 9CFU / mL, 1L in total). 5-6g lactose and 5-6g skim milk powder (5% added) were added to 100mL ultrapure water for autoclaving (121°C, 15min). After cooling, the bacterial sludge was resuspended. The bacterial concentration was 1-7×10 10 In the present invention, lactose can penetrate the cell wall and enter the cell, increase the concentration of solutes in the cell, maintain the osmotic pressure balance inside and outside the cell, and prevent the cell from shrinking due to excessive dehydration during the freeze-drying process; skim milk powder can form an outer membrane on the surface of bacterial cells, thereby protecting the cells from freezing damage.

[0038] (3) Preparation of bacterial powder: The prepared bacterial suspension was pre-frozen at -40°C for 12 h, and then placed in a freeze dryer for vacuum freeze drying at -60°C and 5 Pa for 48 h to obtain duck-derived plant lactobacillus freeze-dried bacterial powder; the number of viable bacteria in the bacterial powder was 1 to 4×10 11 CFU / g, this biological preparation is obtained after adding propyl gallate.

[0039] (4) Preparation compounding: The freeze-dried bacterial powder of duck-derived Lactobacillus plantarum is mixed with propyl gallate in a mass ratio of 2 to 6:1 (preferably 4:1) to form a compound biological preparation. When the preparation is used as an additive in feed or drinking water, the recommended addition amount is 140 mg / kg.

[0040] Example 3: Effects of duck-derived Lactobacillus plantarum and biological preparations on the production performance of meat ducks

[0041] The experiment selected 120 7-day-old Beijing ducks and randomly divided them into 3 groups according to body weight, with 5 replicates in each group and 8 ducks in each replicate. Two treatment groups and 1 control group were used (see Table 2 for the experimental design), CON group: blank control group, fed with a basic diet (see Table 1 for the basic diet composition and nutritional components); LP group: added duck-derived plant lactobacillus CGMCC No. 26622 bacterial preparation on the basis of the basic diet; LP&PG group: added duck-derived plant lactobacillus CGMCC No. 26622 and propyl gallate in proportion to the basic diet; the feeding cycle was 5 weeks, and after the end of the 5th week, the ducks were slaughtered and sampled.

[0042] Table 1: Basic feed composition for broiler ducks

[0043]

[0044] 1 This premix provides the following micronutrients (per kg complete food): VA 12 000IU, VD3 2 500IU, VE 20mg, VK3 3mg, VB1 3mg, VB2 8mg, VB6 7mg, VB 120.03mg, D-pantothenic acid 20mg, niacin 50mg, folic acid 1.5mg, biotin 0.1mg, choline 500mg, copper (added copper sulfate) 9mg, zinc (added zinc sulfate) 110mg, iron (added ferrous sulfate) 100mg, iron (added ferrous sulfate) 100mg, selenium (added sodium selenite) 0.16mg, iodine (added potassium iodide) 0.6mg.

[0045] 2 The nutritional content is calculated.

[0046] Table 2: Design table of meat duck breeding experiment

[0047]

[0048] The results in Table 3 show that at 42 days of age, the average daily weight gain of broiler ducks fed with Lactobacillus plantarum and biological preparations was significantly higher than that of the control group (P < 0.05); there was no significant difference in the average daily feed intake (P > 0.05), while the feed-to-weight ratio of the biological preparation group was significantly lower than that of the control group (P < 0.05). The above results indicate that Lactobacillus plantarum and its biological preparations can increase the weight of broiler ducks, and the composite biological preparation can significantly improve the feed conversion rate, with better effects.

[0049] Table 3: Effects of different feed additives on growth performance of 7-42 day old ducks

[0050]

[0051] The same data with different lowercase letters indicate significant differences (P<0.05), different uppercase letters indicate extremely significant differences (P<0.01), and the same or no lowercase letters indicate no significant differences (P>0.05).

[0052] Example 4: Effects of duck-derived Lactobacillus plantarum and biological agents on slaughter performance

[0053] The results in Table 4 show that compared with the control group, the half-evisceration rate, full-evisceration rate, breast muscle rate and abdominal fat rate of the Lactobacillus plantarum group and the biological preparation group were significantly increased (P < 0.05), while the slaughter rate and leg muscle rate of the biological preparation group showed an upward trend compared with the control group (P > 0.05).

[0054] Table 4: Effects of duck-derived Lactobacillus plantarum and compound bacterial preparations on slaughter performance of 42-day-old meat ducks

[0055]

[0056]

[0057] Example 5: Effects of duck-derived Lactobacillus plantarum and biological agents on meat quality

[0058] As can be seen from Table 5, compared with the control group, the pH of duck meat in the plant lactobacillus group and the composite biological preparation group increased significantly (P < 0.05), while the brightness (L*) of the plant lactobacillus group was significantly lower than that of the control group (P < 0.05), the redness value (a*) of the composite biological preparation group showed an increasing trend, and the yellowness value (b*) of both groups increased; the pH showed an increasing trend compared with the control group, and the freeze-drying loss rate showed a decreasing trend (P> 0.05). This shows that the breast acidity of duck meat in the plant lactobacillus and composite biological preparation groups is lower than that of the control group, but the brightness of the breast meat of duck meat in the plant lactobacillus group is reduced, the redness is reduced, and the yellowness is increased, and the addition of biological preparations can return the brightness, redness, and yellowness of the breast meat of duck meat to normal levels.

[0059] Table 5: Effects of duck-derived plant lactobacillus and compound bacterial preparations on duck meat quality

[0060]

[0061] As shown in Table 6, compared with the control group, the elasticity of the biological preparation group increased significantly (P < 0.05), while the shear force of the plant lactobacillus group increased significantly (P < 0.05). There were no significant differences in hardness, viscosity, adhesiveness, chewiness, and resilience among the groups (P > 0.05). Shear force is one of the indicators for evaluating the tenderness of meat products. The shear force of breast meat of ducks fed with duck-derived plant lactobacillus feed was significantly higher than that of the control group and the composite biological preparation (P < 0.05), which reduced the tenderness of duck meat; while the breast meat shear force of ducks fed with composite biological preparations was reduced (P > 0.05), the tenderness of duck meat was improved, and the elasticity of duck meat was increased.

[0062] In summary, the results in Tables 5 and 6 show that feeding the composite biological preparation can improve the elasticity, color and tenderness of duck meat, indicating that duck-derived Lactobacillus plantarum and propyl gallate have complementary effects on the texture characteristics of duck meat.

[0063] Table 6: Effects of duck-derived plant lactobacillus and compound bacterial preparations on duck meat texture and shearing indexes

[0064]

[0065] Example 6: Analysis of the effect of duck-derived Lactobacillus plantarum fermentation product and gallic acid ester on inhibiting harmful bacteria in vitro

[0066] Four common duck harmful bacteria (Escherichia coli, Riemerella anatipestifer, Salmonella, and Staphylococcus aureus) were selected and activated and cultured for 24 h. The bacterial solution was eluted and added to the blank culture medium. The OD was adjusted. 600nmThe value is about 0.3, and the duck source plant lactobacillus supernatant (fermentation product), propyl gallate, duck source plant lactobacillus fermentation product & propyl gallate prepared in Example 1 are added respectively, wherein the addition ratio of plant lactobacillus fermentation product to harmful bacteria is 1:9 (low concentration), and the addition concentration of propyl gallate is 0.25 mg / mL. The 24-hour growth effect (OD 600nm The grouping is shown in Table 7.

[0067] Table 7: Experimental design of the combination of duck-derived Lactobacillus plantarum and propyl gallate to inhibit harmful bacteria in ducks

[0068]

[0069]

[0070] Depend on Figure 7 The results of the antibacterial assay showed that propyl gallate had a delayed growth effect on Escherichia coli when added at a concentration of 0.25 mg / mL, while when the Lactobacillus plantarum fermentation product was added at a concentration of 1:9, the duck-derived Lactobacillus plantarum fermentation product had no obvious inhibitory effect on Escherichia coli, and when the addition concentration was 1:9, the duck-derived Lactobacillus plantarum fermentation product and 0.25 mg / mL propyl gallate were used in combination to have a good inhibitory effect on Escherichia coli within 24 consecutive hours, causing Escherichia coli to grow very slowly. This shows that when the addition concentration is 1:9, the combination of duck-derived Lactobacillus plantarum fermentation product and 0.25 mg / mL propyl gallate can effectively inhibit the growth of Escherichia coli, and the antibacterial effect of the combination of the two is better than that of the single use.

[0071] Depend on Figure 8 The results of the antibacterial test showed that the duck-derived Lactobacillus plantarum fermentation product had a delayed growth effect on Riemerella when added at a concentration of 1:9, while propyl gallate had no inhibitory effect on Riemerella when added at a concentration of 0.25 mg / mL. The combination of duck-derived Lactobacillus plantarum fermentation product and 0.25 mg / mL propyl gallate at a concentration of 1:9 had a strong inhibitory effect on Riemerella within 24 consecutive hours, preventing Riemerella from growing. This shows that the combination of duck-derived Lactobacillus plantarum fermentation product and 0.25 mg / mL propyl gallate at a concentration of 1:9 can effectively inhibit the growth of Riemerella, and the antibacterial effect of the combination of the two is better than that of the single use.

[0072] Depend on Fig. 9The results of the antibacterial test showed that the duck-derived Lactobacillus plantarum fermentation product had no inhibitory effect on Salmonella when added at a concentration of 1:9, while propyl gallate had a certain effect of delaying the growth of Salmonella when added at a concentration of 0.25 mg / mL. At an addition concentration of 1:9, the duck-derived Lactobacillus plantarum fermentation product and 0.25 mg / mL propyl gallate had a high inhibitory effect on Salmonella within 24 consecutive hours, preventing Salmonella from growing within 20 hours. This shows that the combination of duck-derived Lactobacillus plantarum fermentation product and 0.25 mg / mL propyl gallate at an addition concentration of 1:9 can effectively inhibit the growth of Salmonella, and the antibacterial effect of the combination of the two is better than that of using them alone.

[0073] Depend on Fig.10 The results of the antibacterial test showed that the combination of duck-derived Lactobacillus plantarum fermentation products and propyl gallate at an addition concentration of 1:9 had a delayed growth effect on Staphylococcus aureus, while the combination of duck-derived Lactobacillus plantarum fermentation products and 0.25 mg / mL propyl gallate at an addition concentration of 1:9 had a highly effective inhibitory effect on Staphylococcus aureus, preventing the growth of Salmonella within 24 hours. This shows that the combination of duck-derived Lactobacillus plantarum fermentation products and 0.25 mg / mL propyl gallate at an addition concentration of 1:9 can effectively inhibit the growth of Staphylococcus aureus, and the antibacterial effect of the combination of the two is better than that of the single use.

[0074] The above results show that the combination of duck-derived Lactobacillus plantarum fermentation products and 0.25 mg / mL propyl gallate at an addition concentration of 1:9 can significantly inhibit the growth of four common duck harmful bacteria. This indicates that the combination of Lactobacillus plantarum and 0.25 mg / mL propyl gallate at an addition concentration of 1:9 has a high inhibitory effect on the above duck harmful bacteria.

[0075] Example 7: Effect of duck-derived Lactobacillus plantarum and biological preparations on the storage and preservation of feed

[0076] Accurately weigh 0.1 g of feed into a centrifuge tube, add 10 mL of ultrapure water, mix well, centrifuge at 6000 r / min for 10 min, and take the supernatant to measure the pH value using an electronic acidity meter.

[0077] As shown in Table 8, the pH values ​​of each group showed a downward trend as the storage time prolonged, among which the pH of the CON group was the lowest during the storage period, the pH decline trend of the LP group was relatively lower than that of the control group, and the pH decline of the PG&LP group was relatively slow, with extremely significant differences among the groups (P<0.01). This shows that the duck-derived plant lactobacillus composite bacteria preparation can delay the storage period of feed and play a certain role in preservation and freshness preservation.

[0078] Table 8: Effects of duck-derived plant lactobacillus and compound bacterial preparations on feed storage pH

[0079]

[0080] In summary, the present invention utilizes the duck-derived Lactobacillus plantarum screened and isolated from the cecal contents of meat ducks to better adapt to the duck's intestinal environment and determine its value, and combines it with propyl gallate to prepare a composite biological preparation, which can reduce the amount of duck-derived Lactobacillus plantarum added, effectively inhibit the reproduction of harmful pathogenic bacteria in ducks, improve production performance and feed conversion rate, improve meat quality, and delay feed acidification; it is suitable for widespread use as a functional health feed additive, and provides important technical support for large-scale duck antibiotic-free or reduced-antibiotic farming.

Claims

1. A composite biological preparation, characterized in that: The composite biological preparation is composed of duck-derived plant lactobacillus freeze-dried bacterial powder and propyl gallate, the preservation number of the duck-derived plant lactobacillus is CGMCC No.26622; the number of viable bacteria in the duck-derived plant lactobacillus freeze-dried bacterial powder is 1.5×10 11 CFU / g~4×10 11 CFU / g; the mass ratio of the duck-derived plant lactobacillus freeze-dried powder to propyl gallate is 2-6:

1.

2. The composite biological preparation according to claim 1, characterized in that The mass ratio of the duck-derived plant lactobacillus freeze-dried powder to propyl gallate is 4:

1.

3. The composite biological preparation according to claim 1, characterized in that The duck-derived plant lactobacillus freeze-dried bacterial powder is prepared by adding lactose and skim milk powder to a bacterial suspension of duck-derived plant lactobacillus and then adopting vacuum freeze drying.

4. The composite biological preparation according to claim 3, characterized in that The mass ratio of the duck-derived plant lactobacillus suspension, lactose and skimmed milk powder is 20:0.5-2:0.5-2.

5. The composite biological preparation according to claim 4, characterized in that: The mass ratio of the duck-derived plant lactobacillus suspension, lactose and skimmed milk powder is 20:1:

1.

6. Use of the composite biological preparation according to claim 1 as an additive in the preparation of poultry feed.

7. A poultry feed, characterized in that: The composite biological preparation according to claim 1 is added to the poultry feed.

8. The poultry feed according to claim 7, characterized in that: The poultry feed is duck feed.

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