Ruminant pellet feed of straw immobilized microalgae and application of ruminant pellet feed

Abstract

The invention belongs to the field of bioengineering, and particularly relates to a straw immobilized microalgae ruminant pellet feed and application thereof. According to the method, chlorella is fixed on the straw, nutrient substances in the pretreated liquid animal waste are used as nutrient supply, the straw inoculated with microalgae is incubated under illumination and dried to obtain dry particles, and the crude protein content and digestibility of the straw are remarkably improved through the treatment process. The dry particles are combined with molasses, salt, premix and calcium carbonate to prepare pellet feed; the crude protein content of the obtained feed particles can reach 12.63%, the crude fiber content is 25.47%, the calcium content is 0.49%, the phosphorus content is 0.24%, and the calcium-phosphorus ratio is about 2: 1. The feed granules are rich in nutrition and suitable for feeding ruminants such as sheep, dairy cows and buffalo. The invention provides an alternative scheme which is more sustainable, more cost-effective and balanced in nutrition, and has a wide market application prospect.

Description

Technical Field

[0001] The invention belongs to the field of bioengineering, and in particular relates to a ruminant pellet feed of straw-immobilized microalgae and application thereof. Background Art

[0002] As one of the largest agricultural countries, China produces a large amount of straw every year, which is generally treated as waste. At the same time, as the largest producer of manure, China produces more than 12 million tons of manure. The direct use of it as fertilizer on farmland is usually limited because the nutrient content is too high, exceeding the allowable soil capacity, which is limited to 170 kg (nitrogen) / hectare / year. In addition, it cannot be discharged directly into water bodies and is often stored for a long time, increasing greenhouse gas emissions. In addition, due to socio-economic constraints, investors often do not adopt treatment technologies. Therefore, how to effectively use manure and recycle straw is a technical problem that needs to be solved urgently. In the search for sustainable agricultural practices, one of the main focuses is to optimize livestock feed to improve productivity, health and cost-effectiveness. Traditional ruminant feed includes a mixture of grains, roughage and supplements designed to meet the nutritional needs of animals. Roughage, such as straw, is usually used for feeding ruminants, and its addition ratio is usually 60%. According to Bell et al., the basic ingredients required for optimal health and growth of ruminants are crude protein, total digestible nutrients, fat, calcium, phosphorus, and vitamins A and E. However, the nutritional value and digestibility of straw are poor, and the crude protein requirement and digestible energy of ruminants are 4.2% and 46.5%, respectively. Straw feeding cannot meet the nutritional needs of animals. In addition, the development of nutritionally balanced feed for ruminants also depends on factors such as age, weight and growth potential. For example, early weaned lambs with moderate growth potential require a diet containing 16.1% crude protein and 73.8% total digestible nutrients, while lambs aged 7 to 10 months need a diet containing 12.1% crude protein and 66.8% total digestible nutrients. Therefore, roughage is generally not suitable for feeding ruminants alone, and concentrated feed ingredients such as corn and soybean meal need to be supplemented to provide nutritional support.

[0003] Existing methods for improving the nutritional value of straw, such as physical treatment (chopping, grinding), chemical treatment (alkali treatment) and biological treatment (enzyme application, microbial fermentation), all have their own series of problems. For example, physical treatment cannot fully decompose the lignocellulose structure of straw to significantly improve digestibility; chemical treatment has chemical residues and environmental problems; biological treatment has problems such as complex operation and low efficiency. At present, there are literature reports on a straw-based cattle feed that converts straw into a product with high economic value through more than ten reasonable nutritional ratios of conventional raw materials such as corn distiller's grains, soybean meal, wheat bran, sucrose, yeast culture, sweeteners, etc. There are also literature studies on the use of enzymes such as cellulase and hemicellulase to treat lignocellulosic materials under acidic conditions with high dry matter content. However, these methods require complex and expensive processing, cumbersome operation, and low economic benefits.

[0004] Current technologies for processing and utilizing agricultural byproducts such as straw present several challenges and limitations. Although straw is abundant and often considered for animal feed, its inherent low nutritional value and poor digestibility have hindered its widespread adoption. Unprocessed straw contains high levels of lignin and silica, which significantly reduce its digestibility and nutrient absorption by ruminants. These components also hinder the decomposition of straw in the rumen, resulting in reduced energy utilization and growth performance of livestock.

[0005] It is worth mentioning that microalgae can also be used as a feed ingredient; studies such as Yan et al. and Karapangiotidis et al. have shown that adding microalgae to feed formula has a positive effect on fish feeding. However, the current use of microalgae generally involves microalgae harvesting systems, aeration systems, etc., and its utilization cost is still 2-4 times the cost of traditional fish meal and soybean meal, respectively; and its use in the field of animal feed is rarely reported. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention aims to solve the above problems and provides a ruminant pellet feed with straw-immobilized microalgae and application thereof.

[0007] The present invention provides a new cost-effective, high-density, non-harvesting Chlorella cultivation technology by fixing Chlorella on straw and using nutrients in pre-treated liquid animal manure as a nutritional supplement. The processing process includes two main stages; the first stage is to treat the straw; the second stage is to prepare feed pellets by mixing the modified straw with other additives in a specific ratio.

[0008] The present invention provides a simpler, more economical and effective solution, using microalgae to convert straw into pelleted feed that meets animal production needs and improves digestion and production efficiency. The present invention improves the comprehensive utilization of straw through microalgae, especially Chlorella processing technology, increases the digestibility and nutritional value of straw, and does not require complicated procedures or expensive instruments, which is a huge advantage over existing methods.

[0009] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0010] A ruminant pellet feed with straw-immobilized microalgae, the feed comprising the following components in percentage by mass:

[0011] Dry granules 97%-98.2%, molasses 1%-1.5%, salt 0.5%-1%, premix 0.1%-0.2%, calcium carbonate 0.2%-0.25%;

[0012] The premix consists of vitamins and minerals; the mass ratio of the vitamins to the minerals is 1:1.

[0013] The preparation steps of the dry particles are as follows:

[0014] (1) Mixing ruminant feces with tap water and adjusting the total solid content to 1%-3%; then filtering for the first time to obtain a mixture; aerating the mixture for aerobic pretreatment to obtain a liquid manure preparation solution after aerobic pretreatment; then filtering the liquid manure preparation solution after aerobic pretreatment for the second time under a certain temperature condition to obtain a filtrate; and adding nitrate nitrogen to the filtrate, and finally sterilizing it under high pressure to obtain a liquid manure culture medium;

[0015] (2) grinding the dried straw under certain temperature conditions to obtain straw particles, and then sterilizing the particles to obtain sterilized straw particles;

[0016] The liquid manure culture medium prepared in step (1) is used to inoculate the sterilized straw particles, with 10-20 ml of the liquid manure culture medium used for each gram of the sterilized straw particles; the particles are incubated and cultured after incubation and culture, and then dried to a constant weight to obtain dry particles.

[0017] Preferably, the ruminants in step (1) include but are not limited to cattle and sheep.

[0018] Preferably, the aerobic pretreatment in step (1) is performed by air ventilation at a ventilation rate of 0.5 vvm for 48 hours; a defoaming agent may also be added to the liquid manure preparation solution after aerobic pretreatment to control bubbles, and the amount of the defoaming agent added is 0.01% based on the mass of the liquid manure preparation solution.

[0019] Preferably, the high pressure sterilization conditions in step (1) are 121° C. for 15-20 min; the diameter of the filter used in the first filtration is 1-2 mm; and the diameter of the filter used in the second filtration is 100-120 μm.

[0020] Preferably, the certain temperature condition in step (1) is 20-25° C.; and the final concentration of nitrate nitrogen in the filtrate is 147.89 mg / L.

[0021] Preferably, the certain temperature condition in step (2) is 65-75°C; the sterilization condition is: sterilization at 121°C for 1 to 2 hours.

[0022] Preferably, the incubation conditions in step (2) are: 24-26°C, 117 μmol / m2 / s light intensity, and an incubation time of 10-12 days; after 4 days of cultivation, the sterilized straw particles are inoculated with liquid manure culture medium, using 60-70 ml per gram of sterilized straw particles; and the drying temperature is 40-45°C.

[0023] The method for preparing the ruminant pellet feed with straw-immobilized microalgae comprises the following steps:

[0024] After mixing the components according to the formula, a mixture is obtained; the mixture is sent to a granulator with a 6mm mold for granulation. After granulation, the obtained particles are cooled to room temperature to obtain pellet feed.

[0025] The ruminant pellet feed of the straw-immobilized microalgae is used for animal feeding, and the animal is a ruminant.

[0026] 1. Nutritional content of feed pellets:

[0027] The nutritional content of feed pellets: crude protein (CP) ≥12.5%; fat ≥2.9%; total digestible nutrients (TDN): ≥65%; crude fiber (CF) ≥25%; calcium (Ca) ≥0.45%; phosphorus (P) ≥0.20%; Ca / P ratio is 1.95 to 2:1.

[0028] It can meet the nutritional needs of animals at all growth stages (including maintenance, growth, lactation and late pregnancy).

[0029] 2. Adaptability of feed pellets to different types of ruminants:

[0030] This step highlights the adaptability of feed pellet formula to sheep, dairy cows, etc. at different reproductive stages, ensuring that the nutritional needs of sheep at various stages such as maintenance, growth, lactation and late pregnancy are met.

[0031] Maintenance ration: Provides basic protein, energy and minerals to meet basic nutritional requirements; Growth ration: Suitable for older, growing sheep, providing sufficient protein and energy; Lactation ration: Ensures that sufficient protein and minerals are provided to support milk production; Late pregnancy ration: Meets the increased nutritional needs of pregnant ewes. Dairy cows require high-quality feed, reaching 3% of their body weight per day for optimal milk production. Protein content below 6% will significantly reduce feed intake. Formulating a dairy cow diet involves calculating specific requirements based on body weight and milk production, adjusted to 4% fat-corrected milk. The intake of total digestible nutrients, energy, protein, calcium and phosphorus must be balanced.

[0032] The feed pellets prepared by the invention can meet the nutritional needs of sheep and cows at different growth stages without the need for additional supplements. The feed pellets have good palatability and can be directly fed to animals.

[0033] Meeting these nutritional requirements can ensure optimal milk production. For example, dairy cows usually produce 15-20 kilograms of milk per day. Feeding the granular feed of the present invention can effectively meet the application requirements of dairy cows.

[0034] Beneficial effects of the present invention:

[0035] Compared with the prior art, the Chlorella used in the present invention has a high-value protein content ranging from 51% to 58%, and accumulates about 20% of lipids; it uses light energy and carbon dioxide in the atmosphere through photosynthesis to produce extracellular polymers, including polysaccharides, proteins, etc. These polysaccharides can be used as fixatives in the fixation process. Moreover, Chlorella is the most abundant genus, can be colonized and attached to various support materials, and is easy to use.

[0036] The present invention creatively cultivates Chlorella directly on straw, and uses microalgae to convert straw into complete pellet feed that meets animal production needs and improves digestion and production efficiency; Chlorella not only increases the protein content, but also increases the digestibility of straw, and also introduces essential vitamins and minerals, and can improve digestibility, reducing the need for additional grain supplements. The present invention improves the comprehensive utilization of straw through microalgae, especially Chlorella processing technology, increases the digestibility and nutritional value of straw, and does not require complicated procedures or expensive instruments, which is a huge advantage over existing methods.

[0037] The present invention adds mineral and vitamin premixes to feed to provide vitamins and minerals required for animal growth; adds molasses to improve palatability, increase animal feed consumption, increase fermentable carbohydrate content, and increase total digestible nutrient value. In addition, salt is added to regulate body functions and increase feed intake. It is added to set the Ca:P ratio to 2:1 and can also serve as a buffer in the rumen to prevent pH from decreasing.

[0038] Therefore, the present invention provides a more sustainable, cost-effective and nutritionally balanced alternative, addresses the limitations of existing technologies, and promotes more efficient and environmentally friendly animal husbandry practices, with broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the process of feed preparation in Example 1. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0041] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art in the art to which the present invention relates.

[0042] Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0043] It will be apparent to those skilled in the art that many modifications and variations can be made to the particular embodiments of the invention described herein without departing from the scope or spirit of the invention.

[0044] Unless otherwise specified, the reagents used in the present invention are all conventional commercially available reagents; the vitamins used therein are purchased from Shanghai MacLean Biochemical Technology Co., Ltd., and the minerals are purchased from Shanghai Eon Chemical Technology Co., Ltd.

[0045] Embodiment 1:

[0046] 1. Feed pellet formula:

[0047] Dry granules 98.17%, molasses 1%, salt 0.5%, premix (vitamins and minerals mixed in a mass ratio of 1:1) 0.1%, calcium carbonate (CaCO3) 0.23%.

[0048] The preparation steps of dry granules are as follows:

[0049] (1) Preparation of liquid manure culture medium:

[0050] Ruminant manure (cow) was mixed with water and adjusted to a total solid content of 2%; the mixture was filtered through a 1 mm mesh sieve; aeration was performed at a rate of 0.5 vvm for 48 hours to remove ammonia and suspended solids to obtain a liquid manure preparation solution after aerobic pretreatment; and a defoamer was added to the liquid manure preparation solution to control foaming, and the addition amount was 0.01% of the mass of the liquid manure solution; sludge was removed and filtered through a 100 micron diameter polypropylene cloth sieve at 25°C to obtain a filtrate. Nitrate nitrogen (final concentration of 147.89 mg / L) was added to the filtrate and autoclaved (121°C, 20 min) to obtain a liquid manure culture medium. This method uses liquid manure as an alternative, cost-effective culture medium for Chlorella, and significantly improves the nutritional properties of the treated straw.

[0051] (2) Cultivation of Chlorella on Straw Introduction: The straw treated by the method showed significant improvements in its nutritional properties, including increased crude protein content, enhanced fat, better digestibility and overall improved energy content.

[0052] The dried straw was ground at 70°C to obtain straw pellets, and then sterilized at 121°C for 1 hour to obtain sterilized straw pellets;

[0053] The sterilized straw particles were inoculated with liquid manure culture medium, and 15 ml of culture medium was evenly sprayed per gram of sterilized straw particles; after 4 days of cultivation, 60 ml of liquid manure culture medium was additionally added per gram of sterilized straw particles; then, the particles were incubated at 25°C and 117 μmol / m2 / s for 12 days, and after incubation, the particles were dried at 40°C to a constant weight to obtain dry particles.

[0054] Nutritional characteristics of dry particles: crude protein content: 12.84%; fat: 3.03%; digestible nutrients: 65.86%.

[0055] 2. Feed preparation method:

[0056] After mixing the components according to the formula, a mixture is obtained; the mixture is sent to a granulator with a 6mm mold for granulation. After granulation, the obtained particles are cooled to room temperature to obtain pellet feed.

[0057] The nutritional content of feed pellets: crude protein (CP): 12.63%; fat: 2.97%; total digestible nutrients (TDN): 65.33%; crude fiber (CF): 25.47%; calcium (Ca): 0.49%; phosphorus (P): 0.25%; Ca / P ratio is 1.96:1 (close to 2:1).

[0058] After the feed is prepared according to the method of the above embodiment, it can be directly fed to ruminants, including sheep and cows.

[0059] Application example 1: Sheep breeding

[0060] The specific nutritional requirements of sheep vary depending on their stage of growth, reproductive status and overall health. Based on the nutritional requirements listed in the table provided, the main dietary components of sheep include crude protein, total digestible nutrients, fat, minerals (such as calcium and phosphorus) and vitamins. Ensuring that these nutritional requirements are met is essential for the growth, reproductive performance and wool production of sheep.

[0061] Crude protein: Essential for growth, tissue repair and wool production. Requirements range from 12% to 18% depending on the age and physiological state of the sheep.

[0062] Total digestible nutrients: Sheep require a total digestible nutrient level of 57.5% to 77.1%.

[0063] Fat: between 2% and 3.5%.

[0064] Minerals (calcium and phosphorus): essential for bone development and metabolic processes; calcium requirements are 0.48% to 0.82%, phosphorus requirements are 0.24% to 0.42%, and the optimal calcium-to-phosphorus ratio is 2:1.

[0065] Vitamins: Important for immune function, vision, and reproduction; the requirement for vitamin A is approximately 381 to 1256 IU / kg, and the requirement for vitamin E is 7 to 10 IU / kg.

[0066] Table 1 Pellet feed composition and sheep nutritional requirements

[0067]

[0068] Sheep are in different stages (maintenance period, growth period, lactation period and late pregnancy), and the corresponding nutrition required is also different. However, it can be seen from the nutritional content of the feed pellets prepared in Example 1 that the nutritional components can effectively meet the feeding needs of sheep at different growth stages.

[0069] Application example 2: Dairy cow breeding

[0070] Dairy cows should be able to consume up to 3% of their live body weight of high-quality feed every day. Total digestible nutrients, metabolizable energy, crude protein, calcium and phosphorus are the most important nutritional parameters. According to the nutritional data required by dairy cows in Table 2, customers can formulate the feed requirements for dairy cows accordingly.

[0071] Table 2 Nutrient requirements of dairy cows

[0072]

[0073] Table 3 Feeding amount and nutritional composition of feed

[0074]

[0075] As shown in Table 3, according to the live weight of the animal, for every 50 kg increase in weight, the feed increases by 1.5 kg; the corresponding milk production of the dairy cow is 15-20 kg / day, and the feed prepared in Example 1 can meet its nutritional needs.

[0076] Table 4 The suitability of the pellet feed of the present invention for ruminants in different growth stages of dairy cows

[0077]

[0078]

[0079] Therefore, the feed prepared by the present invention is very suitable for the feeding of sheep and dairy cows, and can meet the application requirements of their different growth stages; it can also meet the nutritional needs of ewes and dairy cows in late pregnancy, and can provide ewes and dairy cows in late pregnancy with sufficient protein, energy, vitamins and minerals to support fetal development and prepare for lactation.

[0080] In summary, the feed pellets prepared by the present invention can meet the nutritional needs of ruminants.

[0081] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; therefore, although this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A pellet feed for ruminants with straw-immobilized microalgae, characterized in that: The feed is composed of the following ingredients in percentage by mass: Dry granules 97%-98.2%, molasses 1%-1.5%, salt 0.5%-1%, premix 0.1%-0.2%, calcium carbonate 0.2%-0.25%; The premix consists of vitamins and minerals; The preparation steps of the dry particles are as follows: (1) Mixing ruminant feces with tap water and adjusting the total solid content to 1%-3%; then filtering for the first time to obtain a mixture; aerating the mixture for aerobic pretreatment to obtain a liquid manure preparation solution after aerobic pretreatment; then filtering the liquid manure preparation solution after aerobic pretreatment for the second time under a certain temperature condition to obtain a filtrate; and adding nitrate nitrogen to the filtrate, and finally sterilizing it under high pressure to obtain a liquid manure culture medium; (2) grinding the dried straw under certain temperature conditions to obtain straw particles, and then sterilizing the particles to obtain sterilized straw particles; The liquid manure culture medium prepared in step (1) is used to inoculate the sterilized straw particles, with 10-20 ml of the liquid manure culture medium used for each gram of the sterilized straw particles; the particles are incubated and cultured after incubation and culture, and then dried to a constant weight to obtain dry particles.

2. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The mass ratio of the vitamins and minerals is 1:

1.

3. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The ruminants in step (1) include but are not limited to cattle and sheep.

4. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The aerobic pretreatment in step (1) is performed by air ventilation at a ventilation rate of 0.5 vvm for 48 hours; a defoaming agent can also be added to the liquid manure preparation solution after aerobic pretreatment to control bubbles, and the amount of the defoaming agent added is 0.01% based on the mass of the liquid manure preparation solution.

5. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The conditions for high pressure sterilization in step (1) are 121° C. for 15-20 min; the diameter of the filter used in the first filtration is 1-2 mm; the diameter of the filter used in the second filtration is 100-120 μm.

6. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The certain temperature condition in step (1) is 20-25° C.; the final concentration of nitrate nitrogen in the filtrate is 147.89 mg / L.

7. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The certain temperature condition in step (2) is 65-75°C; the sterilization condition is: sterilization at 121°C for 1 to 2 hours.

8. The ruminant pellet feed of straw-immobilized microalgae according to claim 1, characterized in that: The incubation conditions in step (2) are: 24-26°C, 117 μmol / m2 / s light intensity, and an incubation time of 10-12 days; after 4 days of cultivation, the sterilized straw particles are inoculated with a liquid manure culture medium, using 60-70 ml per gram of sterilized straw particles; and the drying temperature is 40-45°C.

9. The method for preparing pellet feed for ruminants of straw-immobilized microalgae according to any one of claims 1 to 8, characterized in that: Here are the steps: After mixing the components according to the formula, a mixture is obtained; the mixture is sent to a granulator with a 6mm mold for granulation. After granulation, the obtained particles are cooled to room temperature to obtain pellet feed.

10. Use of the ruminant pellet feed of straw-immobilized microalgae according to any one of claims 1 to 8 in animal breeding, characterized in that: The animal is a ruminant.

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