CitriStim^TM Improves Performance of Nursery Pigs

CitriStim is a proprietary feed ingredient manufactured by ADM using a controlled fermentation process. Swine nursery trials conducted by ADM have shown CitriStim improved growth by 4.1% and feed efficiency by 1.3% in pigs reared under conditions of low stress and minimal pathogen challenge. CitriStim may provide greater benefits when fed to pathogen-challenged pigs or pigs under stress conditions. MOMENTUM® nursery products from ADM Alliance Nutrition now contain CitriStim as a research-proven and beneficial feed ingredient.

Identifying ways to improve pig performance and economic advantage starts in the nursery phase. Research conducted by ADM over the last two years has shown CitriStim is an effective feed additive, which can help improve nursery pig performance. CitriStim, a Candida yeast product, is a source of mannan oligosaccharides (MOS) and beta-glucans. Researchers have demonstrated MOS can have a beneficial impact on animal growth and health by binding pathogenic gut bacteria. In a review of literature on yeast product usage in livestock, Pettigrew (2000) and Hooge (2003) concluded that yeast products are efficacious and cost effective.

Yeast Basics and Suggested Mode of Action
Yeast
Yeasts are unicellular fungi that have plant and animal-like characteristics. Yeasts have simple nutritional requirements for growth, but are more complex in their structure and reproduction than many plants. Many different applications involve the use of yeast, including fermentation, the by-products of their fermentations, probiotics, and cellular research.

Yeast Cell Walls
The intracellular components of the yeast cell are known as yeast extract. The yeast cell wall is the portion remaining after the inner contents of the yeast cell have been removed. The complexes are organized into larger matrices of branched and interconnected structures that result in what we see as the cell wall (Figure 1). The yeast cell wall contains oligosaccharides, which are complex carbohydrates. Yeast cell wall products consist of two major active components:

• Mannan oligosaccharides

• Beta glucans

Mannan Oligosaccharides
The mannan oligosaccharides or MOS component of the cell wall are considered a type of carbohydrate that may account for benefits observed when livestock are fed yeast products. Thousands of tons of yeast products are added to commercial animal diets annually. For more than 25 years, it has been known that certain carbohydrates, specifically mannose and its analogues, can influence the ability of certain microbes to colonize the gut. Studies by Salit and Gotschlich (1977) demonstrated that D-mannose, yeast mannan, and alpha-methyl-D-mannoside have the ability to interfere with E. coli binding, while other common carbohydrates had little effect (Table 1). Alpha-methyl-D-mannoside was 20 times more potent than yeast mannans and 100 times more potent than D-mannose in inhibiting E. coli attachment to intestinal tissue. From this work, the most important point to consider is that yeast mannan is a good inhibitor of E. coli binding. This means yeast mannan can be beneficial because it prevents E. coli from binding to the gut wall and causing damage.
 

Table 1  Inhibition of E. coli Binding by Selected Carbohydrates^a

                                                     Concentration necessary

Carbohydrate                                     for 50% inhibition

                                                                 micromoles

alpha-methyl-D-mannoside                                  0.5

yeast mannan                                                   10

D-mannose                                                       50

L-mannose                                                   >100,000

D-fructose                                                      3,000

alpha-methyl-D-glucoside                                  18,750

D-glucose                                                      37,500

maltose                                                       >100,000

 ^aAdapted from Salit and Gotschlich (1977)

The structure of carbohydrate linkages or bonds found in mannans can affect whether mannans will be of benefit against pathogenic bacteria. Not all mannans have the same glycosidic bonds. Most plant mannans have beta 1-4 linkages; whereas, yeast mannans have alpha 1-6, alpha 1-2, and alpha 1-3 linkages. Plant mannans are thought to have less ability to bind E. coli and Salmonella compared with yeast mannans because of the differences in carbohydrate linkages. In fact, beta 1-4 linked mannans are considered anti-nutritional. Soybeans typically contain between 1.25 to 1.5% beta-D-mannans.

The ability of D-mannose and similar compounds to inhibit pathogen binding is not limited to E. coli. Bacterial isolates of Salmonella, Proteus, Klebsiella, Clostridium, and several other intestinal pathogens are known to be susceptible to inhibition by D-mannose and yeast mannans. Certain pathogenic bacteria have the ability to bind to the intestinal cell wall by means of fimbrial attachment. Fimbria, which protrude from bacteria, grab receptors located on the surface of the intestinal cell. Binding occurs through "sticky" receptors on the end of the fimbria. These fimbria are known as Type 1 and can be found on certain types of bacteria.

Yeast mannans mimic receptors found on the intestinal wall. This enables them to bind to bacterial fimbria and carry the bacteria out of the intestinal tract, thus preventing bacteria from binding to intestinal cells in large numbers and causing disease. This is a competitive effect. Theoretically, higher mannan content translates to more bacteria bound and removed. Also, yeast mannans are probably available for fermentation in the lower digestive tract. This may be beneficial because intestinal fermentation in moderation has often been observed to provide benefits to the animal, possibly serving as an energy source to the intestine through the production of volatile fatty acids.

The problem of large variation in biological response to yeast product supplementation has been reviewed and a portion of the variability was attributed to disease load of the animals and interactions with other growth promoters. Additional variation may come from the mannan content of the yeast product fed.

CitriStim Product Consistency
CitriStim is manufactured through a controlled fermentation process. The use of consistent, high-quality raw materials and single site production at an ADM fermentation plant helps ensure product consistency. To validate product consistency, samples of CitriStim were analyzed at ADM for moisture, protein, fat, and ash, and sent to the University of Illinois for mannose analysis. The results presented in Table 2 demonstrate CitriStim?s consistency.
 

Table 2  Major nutrient concentrations in CitriStim*
 

Research Results
In Vitro Cell Culture
Laboratory analyses were conducted to determine whether CitriStim was effective at binding E. coli. As discussed previously, one proposed mode of action of yeast MOS is the ability to bind bacterial pathogens in the gastrointestinal tract and block pathogen colonization. The result is a healthier gut environment, which can benefit pig growth. Pathogen binding capacity of yeast can be measured using in-vitro laboratory cell culture methods. CitriStim and several yeast products were sent to an independent laboratory to test their ability to bind E. coli.

The assay measured E. coli remaining in the cell culture solution after E. coli Strain MT21 was cultured with yeast products. E. coli that were bound to yeast were not measured in solution, so the lower the bar value in Figure 2, the better the E. coli binding capacity. Results indicted that CitriStim had similar binding capacity to two yeast products (YP2 and YP3) and better binding capacity than three yeast products (YP1, YP4, and YP5). The data suggest that CitriStim is effective in binding pathogens that may be found in the gastrointestinal tract.

Swine Nursery Trials
A series of nursery trials conducted by ADM have shown consistent improvement in nursery pig growth and performance with the addition of CitriStim to rations. Nursery pigs were fed a four-phase feeding program, using CitriStim as a replacement for a competitive yeast product in MOMENTUM 5-10, 10-15, 15-25, and 25-50 products.

Four nursery studies (Table 3) have shown that pigs fed MOMENTUM nursery products containing CitriStim had an average daily gain improvement of 4.12% and feed efficiency improvement of 1.29% compared with pigs fed MOMENTUM nursery products containing the competitive yeast product.

Table 3  Effects of Adding CitriStim to MOMENTUM Nursery Products*
 

*A lower case letter ^a indicates a tendency to be statistically significant (P < 0.10) and an upper case letter ^A indicates significant differences (P < 0.05)

Using the ADG improvement of 4.12% and assuming an initial weight of 11 lb and a daily gain of 1.0 lb/day for a feeding program using the competitive yeast product, pigs fed the MOMENTUM nursery products containing CitriStim would be 1.73 lb heavier after a 42-day nursery phase (Figure 3).

Two more nursery trials were conducted to evaluate the efficacy of CitriStim using a different approach. One of the major differences between these two trials and the other four trials was that the competitive yeast product was not included in all experimental diets. Therefore, these trials tested the performance improvement potential of CitriStim compared with a negative control (no yeast product). Based on the averages of these two studies, adding CitriStim improved daily gain by 7.13% and feed efficiency by 3.40% (Table 4).

Table 4  Impact of CitriStim on Performance of Nursery Pigs*
 

*A lower case letter ^a indicates a tendency to be statistically significant (P < 0.10) and an upper case letter ^A indicates significant differences (P < 0.05).

Compared with feeding no CitriStim, pigs fed CitriStim were 3.26 lb heavier in the first trial (E6096; Figure 4) and 2.48 lb heavier in the second trial (S04107; Figure 4).

ADM Alliance Nutrition, Inc. , a wholly owned subsidiary of the Archer Daniels Midland Company