Advances in the study of forage silage additives.

the progress of research on forage silage additives
WaTSun Ming 1, Wang Yuqun 1, Xu Luxing 2, Zhang Jinhua 3
WaT( 1. Double Peak County, Hunan Province Livestock and Fisheries Bureau, Hunan Twin Peaks 417700; Guizhou Normal University, Guiyang 550001; 3. Guizhou Institute of Livestock and Veterinary Medicine, Guiyang 550005) abstract: In order to improve the fermentation efficiency of forage grass silage, improve fermentation quality, modulation silage often use additives, the article summarizes the recent research progress of silage additives. According to its mechanism of silage additives can be divided into 4 categories, namely, fermentation promotion additives, fermentation inhibition additives, aerobic metamorphic inhibitors, nutritional additives and so on. Lactobacillus has been widely used because of its characteristics of promoting aerobic stability, inhibiting secondary fermentation, producing antibacterial substances and inhibiting harmful microorganisms. The effect of cellulase preparation addition is mainly influenced by the characteristics of the enzyme itself, the characteristics of silage raw materials and the management of silage, and its added effect has yet to be further studied. Green juice fermentation liquid is a new type of silage additive, which has the characteristics of convenient extraction and simple production, and can obviously improve the fermentation quality of silage raw materials. Future applications of forage silage additives should comprehensively consider environmental factors, strengthen the activity of enzymes research, pay attention to multidisciplinary comprehensive analysis, with cellulase and lactic acid bacteria, green juice fermentation, sucrose, tolic acid and other conventional silage additives may make progress.
WaT .Keywords: forage; Additives; silage; Progress
WaTIn-Graph Classification Number: S816. 5 plus 3 Document Identification Code: A Article No. : 1007 - 1474 (2014) 06 - 0015 - 05 In recent years, with the development of the domestic economy and society, the per capita standard of living has increased, the demand for meat, milk, eggs and quantity and quality are on the rise, the status of grassland animal husbandry is more important. The development of grassland animal husbandry is an important way to ensure the effective supply of animal products, alleviate the contradiction between food supply and demand, and enrich the dietary structure of the residents, while silage is an important way to preserve and develop feed resources and develop "an effective way of food-saving animal husbandry". In the early stage of the research and development of silage processing, silage technology mainly took the experience of previous generations, and gradually changed to the technical level with the in-depth development of science and technology, and additives played an increasingly important role in the whole process of silage development. This paper analyzes the progress of the research on silage additives at home and abroad in recent years, and makes a prospect, aiming to provide reference for future silage research.
WaT .1· Fermentation promoter
WaTfermentation promoter is a composite preparation, composed of yeast leachate, enzyme preparation and inorganic salt, with the advantages of enhancing the environmental tolerance of raw materials, shortening fermentation time, optimizing fermentation index, promoting the decomposition of raw materials, and improving the utilization rate of raw materials. Fermentation promoters accelerate the production of lactic acid by promoting lactic acid bacteria (LAB) activities, causing the pH of the silage material to drop rapidly to 4. 0 s 0. 2, inhibittheed the reproduction of harmful microorganisms. It mainly includes lactic acid bacteria, carbohydrate-rich substances and cell wall degradation enzymes.
WaT .1. 1 Lactobacillus inoculation
WaTin general, the number of lactic acid bacteria attached to the silage raw materials is insufficient, and most of them are undesirable bacteria, and the early silage of lactic acid bacteria reproduction is slow, resulting in rapid reproduction of harmful microorganisms, inhibiting the reproduction of lactic acid bacteria, especially bean grass is more obvious. In general, the effective concentration of lactic acid bacteria is 105 /g fresh grass as the standard value in vegetation where lactic acid bacteria proliferate rapidly and dominates vegetation. Tanaka and Bender G R 5, among others, have proposed that lactic acid inoculations as silage additives should have the following conditions: (1) strong vitality, dominant in competition with other microorganisms; ( 2) can carry out the same type of lactic acid fermentation, so that the fermentation of self-sugar produces a large amount of lactic acid, that is, the plant raw materials carbohydrate has a strong fermentation capacity; ( 3 ) Has a strong acid resistance, so that the pH quickly reduced to 4. 0 below, inhibiting the activity of other microorganisms; ( 4) can ferment fructose, glucose, sucrose, fructose, preferably fermented sugar; (5) cannot produce glucan or glycol from sucrose (fructose), and the above two processes are accompanied by dry matter loss in the form of CO2; ( 6) Does not cause the fermentation of organic acids; (7) a wide range of growth temperatures, which can be grown in the range of 0 to 50 degrees C; 8) Be able to survive on silage raw materials with low water content (e.g. semi-dry silage); ( 9) The ability to hydrolyse proteins. Adding lactic acid preparation is an effective method to artificially expand the lactic acid bacteria population in the silage raw materials, the main use of lactic acid bacteria species have plant Lactobacillus, enterococci, glycoccal, cheese lactobacillus. When the number of lactic acid bacteria attached to the surface of raw materials is small, the addition of lactic acid bacteria can ensure the number of lactic acid bacteria required in the initial silage fermentation, so that as soon as possible into the lactic acid fermentation stage, pH rapid decline, protein hydrolysis is suppressed, the concentration of NH3-N in silcesis, acetic acid and butyric acid content decreased, lactic acid content increased, and ultimately can guarantee fermentation quality. In the production practice, the effect of lactic acid bacteria vaccination is influenced by many factors, such as bacteria type, inoculation amount, WSC content, etc. Research by Bolsen, etc. , Sheperd, etc. , has shown that lactic acid inoculations are used better in silage. Some studies have also suggested that the inoculation of the plant Lactobacillus Lactobacillus lactobacillus in the mixed silage of rye grass and duck-toched has found no beneficial effect on the quality of silcesis after vaccination, possibly due to a drop in the initial fermentation to pH of 5. Lactic acid production is slow when below 0. The ideal inoculation should be to add plant Lactobacillus to a pH of 5. 0 to 6. 5 Active bacteria, the effect may be better. Meeske et al. reported that after the addition of lactic acid bacteria in corn silage, it was found that lactic acid bacteria had no effect on the aerobic stability of the silage. Kung and so on added a special type of fermented lactic acid bacteria to barley silage, and found that the silage contains a higher concentration of acetic acid, which has strong antifungal function, improving the aerobic stability of barley silage. After adding LAB in silcesizing to produce a large amount of lactic acid, but the low content of volatile fatty acids, resulting in the silage tend to aerobic deterioration of the material, so the effect of lactic acid bacteria inoculation on the aerobic stability of the silage material is currently to be studied, different kinds of LAB in different environments, lactic acid preparation syllin sydment effect and WSC content, buffer energy value, water content, temperature and cell composition changes, the use of a certain lab as a separate inoculation can not be adapted to the actual production of a certain lab. Therefore, the choice of lactic acid bacteria inoculation agent more tend to multi-type lactic acid bacteria species combined use, a variety of bacteria mixed preparations become one of the current research hot spots, screening of good bacteria or strains, through advanced preservation technology to maintain a high level of lactic acid bacteria activity in the long term, and applied to the actual production.
WaT .1. 2 Cellulase enzyme
WaTcellulase enzymes is a type of polycomponent enzyme that can degrade cellulose into glucose and is also a fermentation promoter. The cellulase preparations added to the silage feed contain a certain amount of hemicellase, pectinase, protease, amylase and oxidizing reductase in addition to cellulase. Enzyme synthase as a silage additive, its role is mainly reflected in two aspects: First, degradation of cell wall composition, to provide more WSC content for the use of lactic acid bacteria; Second, by the degradation of plant cell walls, reduce the fiber composition, improve the digestion rate of organic substances in silage. Zhao Changyou and other reports, because cellulase contains oxidizing enzyme strains, in which glucose oxidase can consume silage oxygen, create anaerobic environment, inhibit the growth of corrupt bacteria, conducive to the proliferation of anaerobic lactic acid bacteria, quickly produce a large number of lactic acid, so that the pH of silage quickly decreased, to ensure the quality of silage.
WaT .As a silage additive, cellulose decomposition enzymes should have the following conditions: (1) after addition in the early stage of silage fermentation can produce a large amount of sugar; ( 2) At pH 4. 0 to 6. 5 works within range; (3) suitable for a wide range of temperatures; ( 4) Also has a role for grass with low water content; (5) Can exert its decomposition effect in any raw material harvested during any waiting period (maturity); ( 6) can improve the value and digestion of silage feed; ( 7) weak ability to break down proteins; (8) Low price, low cost of use and long-term preservation.
WaT .　　The effects of cellulase addition on the quality of silage cession are reported differently. The addition of cellulose enzymes to the silage of barley and wild peas, etc., only reduces the pH value and does not affect the production of organic acids; Kung et al. reported that the addition of cellulase to the silage of wilting silage did not improve the quality of silage fermentation; Sheperd et al. added cellulase to corn silage, and different doses of enzymes had no effect on the production of acids in fermentation. This may be due to the higher fermentable substrate contained in the corn itself, so the addition of enzymes has little effect on the quality of silage fermentation. Although cellulase can increase WSC content and reduce fiber content in silage, its productivity improvement on livestock is not significant. Jacobs et al. studied the effects of different additives on the cystonic oozing fluid, and found that the increase of silage oozing fluid increased after the addition of enzyme preparations. The cause of the increase in losses: First, biological agents destroy the cell structure, reduce the cell's water retention capacity, so that a large number of cell content logistics out; On the other hand, due to the strengthening of fermentation, a large number of organic matter can be converted into fermentation substrates for LAB fermentation.
WaT .　　1. 3 Rich in sugar substances
WaT in order to increase the nutrition required for LAB growth and reproduction, often in the silage raw materials to add some carbohydrate-rich substances, such as molasses, cereals, whey, beets and so on. Corn crops are rich in WSC, so easy to store, and grass, especially in summer recycled grass and a large number of application stouor and manure of grass WSC content is low, need to add WSC-rich substances to improve fermentation effect. Glucose can provide fermentation substrate directly to LAB, and the general addition of 10 to 20 g /kg is better. However, due to the high price of glucose, not suitable for a large number of applications in production, commonly used by-products of the sugar industry——— molasses instead. Alli et al. reported that green feed with molasses had lower pH levels, high lactic acid and acetic acid and WSC content, low ammonia nitrogen content and better silage quality compared to the control group. O'neil et al. added 2% sucrose to the silage, and the pH and ammonia nitrogen content were lower than those in the control group during the period of 2 to 40 d, and the WSC content in the silsic material increased. In addition to honey, cereal crops can also be used as a silage additive. The addition of cereal crops not only increases the WSC content of silage raw materials, but also reduces the oozing fluid in the silage process, thereby reducing the loss of nutrients.
WaT .　　1. 4 Green juice fermentation
WaT green juice fermentation liquid (PFJ) is a new type of silage additive developed in recent years, similar to lactic acid bacteria preparations, is through fermentation culture plant on the inherent lactic acid bacteria to achieve the rapid proliferation of lactic acid bacteria and the purpose. PFJ compared with the above biological agents its most important featureis is economic and environmental protection, production process is simple, low production costs, operation will not be like acid preparations to cause pollution to the environment, is currently more research additives. Adding PFJ to silage can quickly reduce pH, increase lactic acid content, inhibit Clostridium difficile activity, reduce low protein loss, and its added effect is not affected by silage raw materials, DM content and silage conditions. The addition of green juice fermentation liquid can significantly improve the nutritional value of the silage. Ohshima et al. , the green juice fermentation liquid acts on the silage is not affected by the harvest season, the reproductive period and the storage temperature, and its silage effect is better. However, the stability of PFJ is weak, it is not suitable for long-term preservation, in the actual mass production is used less, its advantages and disadvantages still need to be further studied.
WaT .　　2 . .. Fermentation inhibitors
WaT added fermentation inhibitors are intended to inhibit the growth of undesirable microorganisms in part or in part, so that the pH of silage materials rapidly decreases, and reduces the nutritional loss during fermentation in order to obtain high-quality silage.
WaT .　　2. 1 Organic acid
WaT can be used as an additive in silage organic acids in a variety of, the most commonly used are acetone, formaldehyde, procacid and so on. Torinacid is a reductive organic acid, adding to the torine can improve the final WSC and crude protein quality score, improve fermentation quality; Formaldehyde is a good silage fermentation inhibitor, according to the DM mass score of 0. 6% to 4. 4% added formaldehyde silage, ammonia nitrogen and total lactic acid significantly decreased, effectively inhibited the activity of corrupt bacteria, and can protect the protein. Phillp et al. will be tothelic acid (4. 5 mL/kg) added to the silage, compared to the control group, lactic acid content decreased slightly, soluble sugar increased, other ingredients did not change much. Yang Rich ( 25) in the grassy wood (DM is 27. 36%、38. 69%、44. 98%) To add to the silage of toric acid 4. 0 mL /kg, resulting in a lower ammonia nitrogen content of silage and more soluble carbohydrates, but with DM of 27. 36% of the group works best. But toyric acid has a pungent smell and strong corrosive, poor palatability, affecting livestock appetite, and formaldehyde.