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Based on extensive research and decades of real-world commercial application, seven swine-industry leaders developed an extensive FAQ document to help the industry understand the impacts of soybean meal.

Download the FAQ (PDF, 1.5mb)

Section Two

1. With health-challenged flows, should the industry be using higher levels of soybean meal (SBM)?

SBM has proven beneficial in attenuating both the intake- and weight-gain-suppressing effects of respiratory health challenges, most likely due to the abundant supply of health-promoting functional bioactive compounds in SBM. As with any intervention that may help reduce the severity of the challenge, improvements in livability, morbidity, growth rate and feed efficiency are likely evident. In efforts to compensate for the ongoing challenge of swine respiratory diseases (SRD), typically higher levels (20%–25%) of SBM are recommended, and generally using a minimum amount of SBM in formulations will provide a favorable economic return, which can be verified by side-by-side barn comparisons.

2. Since minimum SBM specifications are beneficial during both summer heat stress and respiratory stress, how do the recommended minimum SBM specifications compare?

Specific recommendations for minimum SBM levels for diets fed to pigs during heat stress and diets fed during respiratory disease stress differ. Specifications that pertain to periods of persistent respiratory disease are shown below. Specifications for summer heat stress are included in Section 3, Q1.

Suggested minimum SBM levels for periods of respiratory disease stress [e.g., Swine Influenza Virus (SIV), Mycoplasma hyopneumoniae (Mhp), Porcine Reproductive and Respiratory Syndrome (PRRS), Porcine Circovirus Associated Diseases (PCVAD)] were determined in a commercial system, but further research is needed. A major problem when implementing the minimums for the disease state is that the timing of disease occurrence varies — the greatest problem may occur during winter/early spring months (e.g., Jan–April). Guidance by a knowledgeable veterinarian, working in collaboration with the nutritionist, is essential to decide whether and when to apply SBM minimums in feed formulations in order to partially counter the effects of respiratory disease.

Note that the maximum levels of L-lysine shown in the table below are applicable to all seasons and do not vary with limits on SBM or dried distillers’ grains with solubles (DDGS). Optimal L-lysine maximums have been determined in a number of commercial systems, but not all nutritionists are aware of this work and the performance effects. A minimum DDGS level is suggested based on field reports of improved bowel health.

Diet Matrix for Respiratory Disease (including PRRS and PCVAD)

3. When is it most common to experience respiratory-health-challenged flows?

Health challenges can occur all year long but probably the most predictable time across flows and systems would be during the winter months, when ventilation issues cause respiratory challenges to increase. These challenges are especially evident when sow farm health becomes unstable due to disease outbreak and/or lateral transfer in the wean-to-finish period. In large production systems, the most common production phases with observed health challenges are the: 1) first three weeks in the nursery, 2) mid-finishing, about 7–10 weeks post-placement, and 3) late-finishing, two to four weeks prior to harvest. Feeding the minimum recommended level of SBM is effective in attenuating the growth-suppressing effect of respiratory disease.

4. What are the functional bioactive compounds in SBM, and what evidence demonstrates their value in health-challenged pig flows?

SBM contains an abundant and diverse supply of growth- and health-promoting functional bioactive compounds that have antiviral, anti-inflammatory, antioxidant and immune-enhancing properties. Both academic and commercial research demonstrates that soybean meal is immunomodulatory when pigs are health-challenged. Research in poultry has demonstrated that the performance benefits are most likely due to the isoflavones present in SBM. For related information see:

Dietary Isoflavone Aglycons from Soy Germ Pasta Improves Reproductive Performance of Aging Hens and Lowers Cholesterol Levels of Egg Yolk

Immunomodulatory potential of dietary soybean-derived isoflavones and saponins in pigs

5. Do processed soy products, such as soy protein concentrates, fermented soy products and so on, (which are often used in nursery diets) contain functional bioactive compounds?

Processed soy products have some of the functional bioactive compounds removed and would not provide the same response as soybean meal. In addition, processed soybean products are typically more expensive and would not be cost-effective, other than, perhaps, in the early nursery phase.

6. Are soybean meal’s functional bioactive compounds more effective on respiratory or enteric health challenges?

Current evidence suggests that SBM has a profound effect when pigs are challenged by respiratory diseases. This has been proven by dramatic improvements in gain and feed efficiency, and a reduction in mortality and morbidity in nursery pigs, when fed diets with higher levels of SBM. More research is needed to determine if there are also enteric benefits. In addition, a growing body of evidence suggests that including soybean hulls in swine diets improves gut health.

7. With the current understanding of the mode of action of functional bioactive compounds, are there other areas within pork production where higher levels of SBM may be beneficial?

Reduction in inflammation is key in many phases, but especially post-farrowing. Although research is needed, the level of SBM used during lactation could be an important “recovery application,” providing value above the nutritional value SBM delivers. Given the respiratory outbreaks that occur on sow farms (i.e., PRRS and SIV), there could be merit in increasing soybean meal levels as well.