In recent years, with the improvement of people's living standards and consumption standards, the quality and output of meat products have aroused widespread concern. The quality and safety of meat products, as well as the shortage of meat products caused by the reduction of per capita arable land, caused by the shortage of meat products and other issues are urgently needed to be resolved. Therefore, fully and effectively develop and utilize various available resources as feed materials, optimize feed processing technology and technology, and vigorously develop fermented feed has become a hotspot of recent research in animal husbandry, and is considered to have broad development prospects in order to achieve feed utilization And the continuous improvement of the rate of food conversion.

The general application of fermentation technology in feed production is of great significance for improving the quality and yield of feed. In order to further promote the wide application of fermentation technology in feed production and make its process technology more perfect, it is necessary to control and optimize the relevant technical conditions in the fermentation process. The temperature, pH, moisture content, fermentation time, and inoculation volume of the fermentation system are all key control parameters that need to be further optimized.

1 temperature

Cultivating the bacteria in a suitable temperature range can make it perform normal growth and metabolism activities, too high or too low temperature may affect the normal growth and metabolism activities of the bacteria. If the temperature is too high, it may cause the microorganisms to grow too fast, and the nutrients in the fermentation system are consumed too much, so that the fermentation cannot proceed normally. Too low a temperature may cause the bacterial growth to be too slow, which may lead to a reduction in fermentation yield.

There have been a large number of experiments to explore and discuss the temperature control during feed fermentation. Gu Bin found that excessively low temperature affects the normal growth of Bacillus subtilis when solid-state fermentation of rapeseed meal is carried out using Bacillus subtilis and Geotrichum candidum to produce polypeptides, and excessive temperature affects the normal growth of Geotrichum candidum. The temperature range is most conducive to the formation of polypeptides, so the optimum temperature is determined to be 32-34 ° C. When Wang Yuan used solid bacteria to ferment soybean meal in solid state, he found that when the temperature was 40 ℃, the fermented soybean meal sample had the highest lactic acid content and the highest degree of soybean protein hydrolysis; "Phenomenon, the color of soybean meal samples appears brown. When Zhang Cuimian used compound bacteria to ferment corn stover meal, he also found that as the temperature increased, the microorganisms in the fermentation system gradually increased, and the pH showed a downward trend, but when the temperature rose above 30 ℃, the number of cells decreased At the same time, the appropriate ambient temperature can also effectively shorten the fermentation cycle. Li Long used compound probiotics to perform solid fermentation of rapeseed meal, corn, wheat flour and soybean meal mixed in a certain ratio, and found that as the temperature increased, the number of lactic acid bacteria also showed an increasing trend, and the pH Reduced accordingly. Compared with when the temperature is lower, the color, smell and texture of the feed are better when the temperature is suitable. The final fermentation temperature is determined to be 35 ℃.

Fermentation temperature will affect the normal growth and metabolism of microorganisms and enzyme activity. A suitable fermentation temperature can effectively increase fermentation yield. Therefore, when the feed is fermented, the temperature of the system needs to be controlled to avoid it being too high or too low.

2pH

The pH of the fermentation system will also have a certain effect on fermentation. During the fermentation of feed, pH affects the enzyme activity. At the same time, the pH will affect the dissociation of some intermediate metabolites, which in turn will inhibit the formation of fermentation products.

Feng Zhen et al. Cultivated Lactococcus under different pH conditions and found that when the pH of the fermentation system was controlled to 6.0, the fermentation activity of the bacteria was the highest. When Tang Xiaopeng and others used Aspergillus niger to carry out solid fermentation of cassava residue, the pH was controlled between 3 and 4, which could ensure that the activity of carboxymethylcellulase was significantly higher than that of other pH treatment groups, and the crude protein content was also significantly higher In other pH treatment groups. During the solid state fermentation of rapeseed meal using microorganisms, Sun Lin found that a too low pH inhibited the growth of various bacterial cells and hindered the normal progress of fermentation. Finally, it was determined that the compound strain had a good effect on rapeseed meal when the pH was 6.0 Fermentation works best.

Therefore, the proper pH in the fermentation system is more conducive to the normal growth and metabolism of the bacteria, maintaining a higher fermentation vitality, so that the fermentation can be carried out with high efficiency, thereby increasing the fermentation yield.

3 water content

A large number of tests prove that the water content is also a major factor affecting the fermentation effect. If the water content is too low or too high, it will affect the normal fermentation.

When Hu Rui et al. Used optimized probiotics to ferment soybean meal, as the moisture content increased, the temperature, pH, and true protein content in the fermentation system all showed increasing trends. Lin Biaosheng and others carried out sealed fermentation of conventional feed and found that the higher the moisture content of the material, the faster the strain grows and the better the fermentation effect. Zhou Mengjia and others used Lactobacillus to ferment the basic feed in solid state. The results showed that too high or too low water is not conducive to the reduction of pH. With the increase of water content, the dry matter recovery rate of fermented feed gradually decreases. When Liu Qiang et al. Conducted the fermentation test of rapeseed meal, as the moisture content increased, the pH gradually decreased. Zhao Hua et al. Found that when the solid-state fermentation of sweet potato residue was carried out, it was found that when the water-to-material ratio was 1.3: 1, the fermentation effect was the best.

Therefore, during the fermentation process, if the water content is too low to meet the needs of microorganisms, the intake of nutrients by the microorganisms will be inhibited, and the growth and metabolism of the microorganisms will not proceed normally. Too much water may worsen the permeability of the substrate and affect the ventilation. It will also inhibit the growth of microorganisms. At the same time, due to too much water, it may increase the drying cost and increase the possibility of contamination by bacteria Sex. Therefore, the moisture content can be reasonably controlled during the fermentation process to avoid too high or too low, which can effectively ensure the fermentation.

4 fermentation time

Fermentation time refers to the time from the beginning to the end of fermentation. The fermentation time also needs to be well controlled during the fermentation process, too long or too short fermentation time is undesirable.

Gao Aiqin and others found in the fermentation test of soybean meal feed that, after the fermentation was carried out to the sixth day, the protein and cellulose in soybean meal had been largely degraded, and the substrate concentration decreased, making its hydrolysis rate tend to be slow; meanwhile, due to non-starch polysaccharide It is degraded to produce a large amount of acid, and the normal growth and metabolism of microorganisms are also affected. When Zhang Pei et al. Used rice husk powder for solid-state fermentation to produce protein feed, they found that the protein content increased the most from day 3 to day 4, the protein content reached the maximum value on day 5, and the protein content showed a downward trend after day 5 This may be related to the autolysis phenomenon of the bacterial species entering the decay period, and the consumption of nutrients may also inhibit the formation of proteins. When Sun Lin et al. Used mixed strains to ferment rapeseed meal, the 24th to 48h of fermentation was the most active period of the fermentation activities of mixed strains. After that, the decreasing trend of anti-nutritional factors such as glucosinolates and tannin gradually became slow. .

In the fermentation process, the substrate feed in the early stage of fermentation contains sufficient nutrients required for microbial fermentation. Microbes can make full use of the nutrients provided and grow vigorously. If the fermentation is ended prematurely, the fermentation yield will be reduced; but when The fermentation time is too long, most of the nutrients in the fermentation system are consumed, so that the growth rate of the microorganisms tends to be slow, the microorganisms may also appear to be autophagy, and the fermentation cost is also increased. Therefore, determining the appropriate fermentation time is necessary to achieve high fermentation yields. Has an important role.

5 inoculation volume

During the fermentation process, excessive inoculum of fermenting microorganisms may cause an increase in oxygen consumption, resulting in a relatively insufficient oxygen supply, affecting the normal growth and metabolism of microorganisms, and also causing waste of materials. And too small inoculum may slow down the growth of microorganisms and reduce the fermentation efficiency.

Xu Yunhe et al. Used Bacillus subtilis to ferment soybean meal in a solid state, the inoculation amount became larger, and the strain's ability to hydrolyze protein also showed enhancement. Qi Hongshan and others conducted a study on mixed-fermentation solid-state fermentation of corn stalks and found that the yield of the obtained fermentation product was the highest when the inoculation amount was 8%. In the experiment of using Aspergillus niger to ferment soybean meal, Yan Hesong found that the protein in the fermentation product gradually increased with the increase of the inoculation amount, but the inoculation amount increased to 1%, and the protein production tended to be saturated.

Therefore, too small inoculation amount will prolong the fermentation cycle and reduce the fermentation efficiency; if the inoculation amount is too large, the excessive product produced may have an inhibitory effect on the normal growth and metabolism of microorganisms in the fermentation system, so that the fermentation ends prematurely.

6 Other

In addition to the above points, the parameters for optimizing the fermentation process technology also have many other influencing factors such as substrate feed particle size, fermentation strain ratio, cell density, and ventilation. In the process of solid-state fermentation, the particle size of the substrate feed is small, which can increase the contact area with the raw materials, but the particle size is too small, it is easy to form agglomeration, which is not conducive to heat transfer and affects the normal growth of microorganisms, so the substrate The size of the feed particle size may also affect the fermentation effect. Qi Hongshan et al. Found in the study of solid-state fermentation of corn stalks by compound bacteria that the ratio of different strains and the ratio of raw materials in the solid medium have an impact on the resulting fermentation products. Kim et al. Found that during liquid fermentation, the cell density increased with the increase of the aeration in the fermentation system. When Zhang Pei et al. Used rice husk powder for solid-state fermentation to produce protein feed, they found that the addition of urea can increase the protein content in rice husk powder, which has a significant impact on the fermentation results. Qiao Li found that in the solid-state fermentation test of soybean meal, adding appropriate amount of corn flour can improve the fermentation effect, which may be related to corn flour promoting the growth and metabolism of microorganisms in the fermentation system.

7 Application prospects of fermented feed

As the fermentation technology becomes more and more mature, fermentation will be more and more widely used in the production practice of pig feed and feeding. After growing and fattening pigs were fed with fermented feed, their daily weight gain and daily feed intake increased. Zhao Zhengxing used fermented feed to feed fattening pigs, and found that daily gain and feed remuneration were improved. At the same time, fermented feed had a significant effect on the improvement of pork quality. After using fermented feed to feed the weaned piglets, Wei Jintao and others found that the growth performance of the piglets has improved, and the stress caused by weaning has been alleviated. A large number of experimental studies have proved that fermented feed shows good results in actual pig production, especially in the feeding process of weaned piglets and fattening pigs.

Although there are still some problems in the application of fermentation technology in feed production, the optimization of related processes still needs a lot of exploration, but fermented feed has shown huge development prospects. According to the key points of the fermentation process, a more detailed and effective fermentation process plan can be established for different strains, substrate feeds and pigs of different growth stages. With the continuous development of science and technology and the continuous maturation of fermentation technology, the technological system of fermented feed will become more and more perfect, and this will have great significance for the efficient and sustainable development of the pig industry.

Note: This article is organized and published by the editor of the Engineering Center. If you have any suggestions or comments and submissions, please add Xiaobian WeChat (13260429991) for interaction.

References

Editor: Ma Weijun; Review: Dr. Liu Jingjing

Source: Pig Industry Science; Author: Wang Jian, Cao Yunhe, Lu Wenqing, Wang Chunlin

Particle Board is mainly used for furniture and carriage of bus, train.The bace&back are the Veneer surface, such as Okoume, Bintangor, Pine, Birch, Poplar, Pencil cedar, Maple, Cherry, White Oak, Sapele, Beech, Red Oak, Ash etc.Melamine paper is the most popular to be as the face board, it is abrasion resistant, heat resistant, fouling resistant, clean is simple.The Engineering wood is also as the face and back surface. It is more cheaper and beautiful, can reach the same wood grain effect as the veneer surface.And we have High Quality Particle board.LULI Group Co. Ltd, well known as the leading manufacturer for wooden, steel and paper products, located in Shouguang, Weifang, Shandong, China. Since the foundation in 1985, it focus on the production of Plywood , venner, MDF, particle board,  Door skin , Blockboard , Finger joint board, OSB, paper, Steel etc.

Particle board Details:

size:1220*2440MM 1250*2000MM 1525*2440MM 1830*2440MM

THICKNESS:9MM-40MM

MATERIAL:POPLAR, COMBINE, PINE

GLUE:E0, E1, E2

CERTIFICATION:CARB, FSC, CE

Particle board

Particle Board,Melamine Particle Board,Particle Board Price,Melamine Laminated Particle Board

Luli Group Co.,Ltd. , https://www.plywoods.nl