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Nonruminant Nutrition Symposium III: Utilization of Fiber in Modern Swine Nutrition 

Summary by: Anne Kamiya, MS

The 2021 American Society of Animal Science Midwest Virtual Meeting session, Nonruminant Nutrition Symposium III (March 10, 2021), comprised of three presenters discussing topics on the utilization of fiber in swine nutrition. The focus of these talks was on the different types of dietary fiber, the roles and functions of fiber in swine nutrition and the chemical and physical characteristics of fiber.

“Dietary Fiber: Chemical and Physical Characteristics and Methods of Analysis” presented by Dr. George C. Fahey, Jr. (University of Illinois at Urbana-Champaign)

This talk was an overview of the definition, function and characteristics of dietary fiber. In the past, dietary fiber was seen as nothing more than roughage and an anti-nutrient. Today however, particularly in the fields of non-ruminant and human nutrition, fiber is being increasingly recognized as a nutritionally important non-nutrient, an antibiotic proxy, a metabolic modifier, a microbiota enhancer and an immune modulator. Fiber can be intrinsic and naturally derived, extracted from complex ingredients, or synthesized from chemical or enzymatic reactions. An overview of the structure and function of plant cell walls and fiber (e.g., insoluble fiber, soluble fiber, resistant starch and oligosaccharides) was discussed extensively and included characteristics like solubility, viscosity and fermentability. Solubility is important because the chemical structure of fiber effects fermentation and which bacteria can use it, how it is used, what end-products are produced and how end-products influence health. The talk ended with discussion of analytical tools for quantifying fiber. Overall, dietary fibers are complex and challenging “nutrients” to evaluate. The functions of fiber are multifactorial, having impacts on immunity, metabolism, gut microbiota, satiety and more. It is also clear this area of study is still largely unexplored and in need of expanded research so the utility of fiber in swine nutrition can be optimized.

“Fiber and Co-product Utilization in Pigs” presented by Dr. R. T. Zijlstra (University of Alberta)

Feed cost, particularly soybean meal, has been increasing over the last decade necessitating cost-effective alternatives. Co-products are food processing byproducts that are of value to the biofuel and food industry. Some co-products include distillers dried grains with solubles (DDGS), oilseed meal and sugar beet pulp. Swine are good converters of co-products (that is to say, they are able to turn co-products into high quality pork protein). However, co-products are very high in dietary fibers which reduces feed intake and digestibility and increases endogenous losses of protein. A significant part of this talk discussed risk management strategies to tackle problems associated with feeding of co-products. Strategies included feed quality evaluation and compensation with feed technology (e.g., added enzymes to enhance digestibility and addition of synthetic amino acids). It was also stated that pigs should eat a normal diet for a week before transitioning to a co-product diet and that diets must be formulated to equal the net energy (NE) and standardized ileal digestibility (SID) of a diet without co-products. Studies that incorporated risk management strategies on canola meal co-products found increased profitability with no change in feed intake, efficiency, or daily gain but noted increased undigested residue and decreased energy and protein digestibility. In conclusion, co-products reduce feed costs but also present multiple challenges which need to be handled via well planned risk management strategies.

“Review of Current Nutrition Knowledge and Practices for Gilt Development” presented by Dr. Mariana Menegat (Holden Farms)

This talk was a comprehensive review of current knowledge and nutritional practices in gilt development. Maximizing lactational performance and longevity requires appropriate prepubertal growth which can be challenging because some lines of gilts grow very rapidly. Nutritional tools thus become essential to optimizing body weight, maturity, tissue composition and reproduction. This talk included an industry survey and a comprehensive review of several pieces of literature on the most fundamental nutritional practices in gilt development. The industry survey outlined common nutritional tools as feeding ad libitium, the use of dietary fiber, lysine and flush feeding. Every study discussed in this talk found that dietary modifications, i.e., feeding a high fiber diet, increasing lysine intake, the use of feed restriction, and lastly, flush-feeding, had significant impacts on gilt energy intake, age of puberty, growth rate, lactation intake, ovulation rate and/or body composition. The take home message was that optimizing gilt development through nutritional factors is complex but highly effective and there must be a balance between reproductive success and longevity when developing a nutrition program.

An unedited recording of this symposium can be found on meeting website.