Figure 1. Intestinal microbial changes after birth of healthy piglets (left: aerobic bacteria, right: anaerobic bacteria Swords et al., 1993)

Before the piglet is born, there are no microorganisms in the intestines. After birth, the sows are inoculated with microorganisms through contact with the birth canal, feces, skin and the external environment. These microorganisms are almost all aerobic microorganisms, including pathogenic bacteria such as E. coli and Salmonella. Piglets are gradually colonized by anaerobic microorganisms such as lactic acid bacteria and cellulolytic bacteria. The intestinal flora of healthy piglets after birth should be as shown in the figure above. Anaerobic bacteria become the dominant flora after 6 hours of birth, which will dominate the subsequent intestinal health and normal physiological functions of the piglets.

Determine whether the piglets are healthy after birth, and whether anaerobic bacteria can quickly become the dominant flora. In addition to the farrowing room environment, labor process, and colostrum, the composition of microorganisms in sow manure has the greatest impact on piglets. The dry feces produced by sows with constipation often contain a large number of aerobic microorganisms, such as Escherichia coli and Salmonella. At the same time, dry feces are often accompanied by poor colostrum quality and prolonged sows' production process. Once newborn piglets are exposed to a large number of pathogenic microorganisms from the source of sow manure, the intestinal flora of piglets will tilt towards aerobic bacteria, which will eventually lead to diarrhea. Therefore, in order for piglets to quickly inoculate the dominant flora, it is necessary to ensure that the sow's intestinal is healthy and the sow is free of constipation.

2. Microbial changes in piglets before and after weaning

Figure 2. Changes in the intestinal Microbial of piglets before and after weaning (left: before weaning, right: LALLEMAND Nutrilon after weaning)

If the piglets consume enough colostrum and regular milk before weaning and consume high-quality creep feed, the piglet’s intestinal flora will be shown on the left side of Figure 2. There are many types of intestinal flora, and the cellulolytic bacteria are the dominant flora, cellulolytic bacteria are absolutely anaerobic bacteria, which can break down fibers in the hindgut, produce short-chain fatty acids, promote the development of epithelial cells and maintain the integrity of the intestinal tract.

The piglet flora after weaning will be as shown on the right. The diversity of the flora will decrease from 900 types before weaning to 700 types. Among them, the number of cellulolytic bacteria decreases, the number of Clostridia and Escherichia coli increases, the harmful bacteria grow rapidly and produce toxins to cause inflammation. reduce the feed intake of piglets, and cause severe diarrhea and death of piglets.

3. Changes of intestinal flora before and after piglet nursery

Figure 3. The effect of long-term use of different doses of ZnO on gastric and ileal microflora (Ingo C Starker, 2014)

In addition to antibiotics, we often use ZnO in large doses for a long time in the nursery stage of piglets to control diarrhea in piglets after weaning, but long-term use of high doses of ZnO can cause beneficial bacteria such as green lactic acid bacteria dropped drasticall, dark green clostridium, blue salmonella and brown green E. coli increased significantly, and once the use is stopped, piglets will have rebound diarrhea.

NO.3 How to maintain the balance of intestinal flora without Antibiotics-free Feed

In the past, antibiotics were often used to deal with various stresses encountered by piglets, but antibiotics kill or inhibit beneficial and harmful bacteria at the same time, resulting in a decrease in microbial diversity, and long-term use of antibiotics at low doses will increase the proliferation of pathogenic microorganisms and cause animal disease. In addition, with the increase of drug resistance and the emergence of super bacteria, we are forced to consider the limitations of antibiotics. The promulgation of anti-antibiotic regulations requires us to make a series of changes to compensate for the lack of antibiotics, maintain the balance of intestinal flora and the health of the intestine and host.

In addition to strengthening daily management and controlling the breeding environment, we can mainly maintain the balance of animal flora through the following aspects.

1. sows

As mentioned above, microbes only appear in the intestines of piglets after birth, and the composition of microbes is mainly affected by sow feces and sow health. Therefore, the intestinal flora of piglets can be regulated by adjusting sows to ensure that piglets can be quickly inoculated with more beneficial bacteria after birth.

The addition of S.boulardii® in the diet can increase the intestinal cellulose-decomposing bacteria of sows through rapid oxygen consumption, improve the health of intestinal epithelial cells, increase intestinal motility, reduce the occurrence of constipation, and effectively regulate the intestinal anaerobic microorganisms of sows and retain it in the feces of the sow, and then the newborn piglets will be exposed to the feces, which can help the piglet's intestines to establish a more obligate anaerobic environment and quickly establish a dominant flora.

2. Feed ingredients, formula and processing technology

When using antibiotics and zinc oxide, diets often only consider the nutritional level, but after the use of antibiotics and zinc oxide is banned, more consideration must be given to the raw materials, formula composition and processing technology of the feed.

The source of dietary protein affects the diversity and composition of the piglet’s intestinal flora. Colloi-rich diets such as soybean meal reduce the relative abundance of lactic acid bacteria, increase the genus The high fishmeal type increases the E. coli/Shigella( It is a type of gram-negative brevis bacilli, the most common pathogen of human bacillary dysentery, mainly in developing countries, commonly known as dysentery bacilli) ratio. The quality and level of protein is also very important. In particular, the content of indigestible protein should be as low as possible to prevent it from being used by opportunistic pathogenic bacteria in the hindgut to proliferate in large numbers, disrupt the balance of the flora, and affect intestinal health.

Another aspect is the granularity. The granularity of different raw materials is different. The finer the protein raw material, the better. For cereals, the finer the better. Fine particles are good for digestion, but they will affect intestinal health.

3. Plant essential oils

Essential oils are volatile organic compounds obtained from plants and have antibacterial, anti-oxidant and anti-viral properties. Adding plant essential oils to piglet diets can increase the number of lactobacilli and reduce E. coli or total coliforms. Li (2012) reported that thymol and cinnamaldehyde can reduce E. coli in piglets, and their effect is similar to that of antibiotics. However, it has also been reported that Chinese herbal extracts and thymol have no effect on Escherichia coli and Salmonella murine.

Since the active ingredients and mode of action of essential oils are still relatively unclear, and there is no real consensus on their effects on Gram-negative or Gram-positive bacteria, more research is needed to develop essential oils with adaptive antibacterial properties .

4. Acidifier

The digestive system of piglets is not well developed at weaning, digestive enzyme activity is very low and secretion is insufficient. Weaning raises gastric pH and reduces enzyme activity. Part of the protein cannot be completely digested and enters hindgut, where it is used by opportunistic pathogens to proliferate. Therefore, it is necessary to lower the pH of the stomach and reduce the effect of weaning on the enzyme activity.

In addition to lowering pH, short-chain and medium-chain organic acids, such as citric acid, propionic acid, lactic acid, and fumaric acid, have been widely used in high-dose piglet feed due to their antibacterial and bactericidal effects and very low cost. . The use of organic acids in weaned piglets is mainly related to a decrease in coliforms and an increase in lactic acid bacteria, although they seem to affect the microbial composition from the stomach to the colon in a broader way.

There are many kinds of acidifiers, including adjusting gastric acid pH and adjusting small intestine pH, so it is best to choose a compound acidifier. In addition to acidifiers, we must also pay attention to the acidity of the raw materials. The special feature is that the acidity of the protein material is very strong. If the protein content is high, the problem will be greater. The protein absorbs more acid and more protein cannot be digested, which will enter the intestines and be used by opportunistic pathogens.

5. Prebiotics

Glenn Gibbsau proposed in 1995 that prebiotics refer to substances that are not digested and absorbed by the host but can selectively promote the metabolism and proliferation of beneficial bacteria in the body, thereby improving the health of the host.

At present, the commonly used prebiotics in feed are oligosaccharides, including fructooligosaccharides FOS, galactooligosaccharides GOS, xylo-oligosaccharides XOS, mannooligosaccharides MOS, inulin, etc. Some microalgae can also be used as prebiotics , such as spirulina, arthrospira, etc., in addition to protein hydrolysates (such as casein hydrolysate, α-whey protein, lactoferrin, etc.) and natural plants vegetables, Chinese herbal medicines, wild plants, etc. can also be used as prebiotics.

Figure 4. The number of E. coli in piglet feces after E. coli challenge

The new generation of yeast derivative Lallemand Yang is a synergistic combination of different components of different yeast strains and specific processing technology. It can adsorb heterotypic flagellates such as E. coli and Salmonella through strong adhesion, and can stimulate different types of immune cells. The receptor activates the body's immune system, thereby maintaining the stability of the intestinal flora, avoiding immune fatigue.

Adding lactose to the diet can be decomposed and supplied by a large amount of lactase secreted in the piglet before 3 weeks of age. After 5 weeks of age, the secretion of lactase is reduced. At this time, lactose can be used as a nutrient by some lactic acid bacteria to increase the number of beneficial bacteria in the intestinal tract.

6. Probiotics

The WHO defines probiotics as living microorganisms, which are beneficial to the health of the host when ingested in sufficient quantities. Probiotics are widely used in diets for weaned piglets, among which lactic acid bacteria, bifidobacteria, enterococci, streptococci and yeasts are the most commonly used. The results of several studies of probiotics on weaned piglets showed an increase in the abundance of lactic acid bacteria or bifidobacteria, a decrease in E. coli, or an increase in the production of SCFA. However, there is still no consensus on the effects of probiotics, because bacteria and yeasts have significant differences in their effects, and their effects on the flora are strain-specific.

Figure 5. The effect of S.boulardii® on the balance of the ileal microflora of piglets (Ghent University 2001)

As a unique special yeast probiotic, S.boulardii® rapidly consumes intestinal oxygen, creates a low-oxygen micro-environment, antibacterial adhesion, and maintains epithelial integrity by neutralizing clostridial toxins, hydrolyzing phosphonate polysaccharides, and upregulating gene expression to maintain epithelial integrity and tight junctions, directly and indirectly strengthen beneficial bacteria, inhibit potential pathogenic bacteria, increase the piglet lactic acid bacteria by 1.2 orders of magnitude, and reduce the intestinal E. coli pathogenic bacteria by 7 times.

7. Fiber

The residence time of chyme in the intestine is too short, and nutrients cannot be fully digested and absorbed. If the residence time is too long, the animal is prone to constipation. The chyme can be used by harmful bacteria in the hindgut, causing a large number of harmful bacteria to proliferate. The most effective way to adjust residence time is fiber.

Fiber is also used by cellulolytic bacteria to produce short-chain fatty acids, which can supply energy to the animal body and maintain the integrity of intestinal epithelial cells. Due to the great variability of fiber and the mycotoxin often contained in fiber raw materials, the use of fiber is prone to cause some problems. In addition, too high fiber content will affect the utilization rate of feed.

In order to reduce the negative effects of fiber use, S.boulardii® can be added when using fiber. S.boulardii® can quickly consume oxygen in the intestines, increase the number of cellulolytic bacteria, and improve the ability to use soluble fiber. Therefore, the supply of soluble fiber can be reduced, thereby reducing the cost of feed formulations.

Summary

Raising pigs is raising the intestine, and one of the signs of intestinal health is the balance of the intestinal flora. Among the many solutions that can maintain the balance of the flora, I believe that S.boulardii® and Lallemand Yang are one of our preferred solutions. No antibiotics in feed, we have been working hard!