Excess backfat deposition and restricted feeding in gestating sows: An overview of mechanisms compromising their health and performance, and regulatory effects of functional dietary fibers.

The definition of dietary fibre as "non-starch polysaccharides plus lignin", that has now been widely accepted, is chemically more distinct than earlier definitions, but still implies some difficulties in its demarcation. In practice, analytical problems and limitations are important, since definition and analysis of dietary fibre are closely related. The delimitation towards more or less undigestible starch fractions, highly soluble polysaccharides, oligosaccharides, and undigestible protein is discussed, as well as phytate, tannins and some other components. Methods for analysis of dietary fibre are based on one or more of three different principles: 1) Weighing after removal of non-fibre components, 2) Colorimetric carbohydrate determinations 3) Specific determination of monomeric constituents by gas-liquid chromatography (GLC) or high performance liquid chromatography (HPLC). Gravimetric methods, using enzymatic degradation of protein and starch, are generally preferred for assay of total dietary fibre, or soluble and insoluble fibre separately. Colorimetric methods are used mainly for determining uronic acids as a measure of pectins. Detailed methods usually employ GLC determination of monomers after acid hydrolysis, but HPLC appear to develop as a convenient alternative. Uronic acids are determined separately by colorimetry or decarboxylation, and lignin usually as Klason lignin, i.e. acid insoluble material.

The 'gold standard' method for the measurement of total dietary fibre is that of the Association of Official Analytical Chemists (2000; method 985.29). This procedure has been modified to allow measurement of soluble and insoluble dietary fibre, and buffers employed have been improved. However, the recognition of the fact that non-digestible oligosaccharides and resistant starch also behave physiologically as dietary fibre has necessitated a re-examination of the definition of dietary fibre, and in turn, a re-evaluation of the dietary fibre methods of the Association of Official Analytical Chemists. With this realisation, the American Association of Cereal Chemists appointed a scientific review committee and charged it with the task of reviewing and, if necessary, updating the definition of dietary fibre. It organised various workshops and accepted comments from interested parties worldwide through an interactive website. More recently, the (US) Food and Nutrition Board of the Institute of Health, National Academy of Sciences, under the oversight of the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, assembled a panel to develop a proposed definition(s) of dietary fibre. Various elements of these definitions were in agreement, but not all. What was clear from both reviews is that there is an immediate need to re-evaluate the methods that are used for dietary fibre measurement and to make appropriate changes where required, and to find new methods to fill gaps. In this presentation, the 'state of the art' in measurement of total dietary fibre and dietary fibre components will be described and discussed, together with suggestions for future research.

Summary The health benefits of including sufficient dietary fibre in the diet have been well described and have formed the basis of dietary recommendations around the world. However, dietary fibre is a complex dietary entity, consisting of many non‐digestible components of food. Debate surrounding the definition and measurement of dietary fibre has resulted in inconsistencies in labelling, description and recommendations set across the world. In the UK, dietary recommendations are made using the fraction of non‐digestible material described as non‐starch polysaccharide that is measured by the Englyst method. However, the Association of Official Analytical Chemists (AOAC) methods, used widely by the food industry, capture a much greater range of non‐digestible material, that some suggest should be included in any definition of dietary fibre. An attempt to resolve such discrepancies, possibly by taking an approach that considers the health effects of fractions not captured in the Englyst method, is probably overdue.Additionally, it is clear that the effects of these various non‐digestible components of dietary fibre are not interchangeable, and it is important that fibre comes from a range of sources to ensure maximum health benefits from the fibre in the diet. Traditional ‘insoluble’ fibres are required to add bulk as well as rapidly fermentable, viscous fibres to bring about cholesterol lowering. There is also a convincing argument for including slowly fermented components, such as resistant starches, that are well tolerated in the digestive system and can bring about improvements in gut function. Currently there is insufficient data from well designed human intervention trials to make specific recommendations on the amounts of these fibre components in the diet, but it may be useful for health professionals to talk in terms of the different food sources of these types of fibre, as well as total fibre amounts.

Impact of the proposed definition of dietary fiber on nutrient databases

Simple SummaryThe addition of fiber to the diet of sows can improve welfare due to prolonging the satiety feeling, which contributes to reducing stereotyped behaviors and providing benefits to reproductive performance. Thus, the present study was carried out aiming to evaluate the effects of lignocellulose-based eubiotic fiber supplementation on the behavior, surface temperature, and reproductive parameters of sows during pregnancy and lactation, as well as the performance of their litters. Dietary eubiotic fiber supplementation for sows in the final third of pregnancy and lactation improves their welfare and performance of their piglets.The present study aimed to evaluate the effects of partially fermentable insoluble dietary fiber supplementation on the behavior, surface temperature, and reproductive parameters of gestating and lactating sows, as well as on the performance of their litters. Four hundred hyper-prolific sows were assigned in a randomized block design with two treatment groups during the gestation phase: Control (C), corn-soy based diets, or corn-soy based diets with daily 55 g supplementation of eubiotic fiber (F) from the 85th day of gestation until the farrowing (late pregnancy). During the lactation phase, the sows were assigned in a 2 × 2 factorial design using the following treatment groups: (1) CC, no fiber included during gestation and lactation. (2) FC, daily inclusion of 55 g of fiber only during late pregnancy. (3) CF, daily inclusion of 55 g of fiber only during lactation. (4) FF, daily inclusion of 55 g of fiber during late pregnancy and lactation. Sows that received dietary fiber supplementation during the final third of gestation increased feed intake during lactation. Piglets from sows supplemented in both phases showed a significant increase in weight at weaning. The dietary supplementation of eubiotic fiber for sows in the end period of gestation and lactation improved performance and welfare, with positive consequences for developing their litters.

2 - Dietary fibre analysis in foods

What is fibre? Current controversies

Since 1953, the definition of 'dietary fibre' (DF) has evolved significantly following an international debate based on analytical progress, new nutritional and physiological knowledge and also private interests of the food industry. The overall tendency is towards an extension of the definition by including resistant starches as well as non-digestible oligosaccharides. This broadened definition is indeed based on physiological considerations as these compounds are not digested in the small intestine and become substrates for the colonic microflora, resulting in fermentation products that have a variety of local and possibly also systemic effects. A main reluctance to use this definition, however, is linked to the difficulty to quantify, with a universal method, the various compounds that fulfil the characteristics defined by this broad definition. At this point, if such a definition were adopted, there are two options, not necessarily antagonistic, which would be (1) to sum the content of NSP, resistant starches and non-digestible oligosaccharides quantified by distinct methods or (2) to use the Association of Official Analytical Chemists (AOAC) method of DF analysis (AOAC 985.29, 991.43) with complementary analyses of the different non-digestible oligosaccharides likely to be present in the food. With none of these solutions being fully satisfying from a scientific but also from a practical point of view, an innovative method has to be proposed within the next decade. The present review describes the various types of DF, effects of DF consumption on physiology and metabolism, past and current definitions, analytical aspects to measure DF and some aspects of DF claims and food labelling.

A definition for dietary fiber was adopted in June 2009 by the Codex Alimentarius Commission based on the recommendation for endorsement of the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) in November 2008. The definition listed three categories of carbohydrate polymers that are not hydrolyzed by the endogenous enzymes in the small intestine of humans. However, the definition left the inclusion of carbohydrates with degrees of polymerization (DP) in the range of 3 and 9 to the discretion of national authorities and left the ‘physiological effect(s) of benefit to health’ as undefined. The ILSI Europe and ILSI North America's committees on dietary carbohydrates organized a forum at the Ninth Vahouny Fiber Symposium in 2010 to discuss these implementation issues with the objective of building scientific consensus on how to resolve them. The results of this session are encouraging and indicated that the scientific community agrees on maintaining a worldwide consensus regarding the inclusion of non-digestible carbohydrates with ≥DP3 as dietary fiber and on a core, non-exhaustive list of beneficial physiological effects that dietary fibers have. These results are consistent with previous worldwide agreements.

Possible implications for health of the different definitions of dietary fibre

Introduction At its 30th session in South Africa in November 2008, the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) agreed on a definition of dietary fibre. Although many aspects of what can be called “dietary fibre” were resolved, the application of this definition raises additional issues in need of resolution. Objectives The goal of this paper is to discuss the major areas at issue in implementing the new Codex definition of dietary fibre: (1) the footnote that individual countries can decide whether they accept oligosaccharides with a degree of polymerization (DP) from 3 to 9 (included) as being fibre; and 2) guidance on which physiological effects are beneficial. Less critical but still important is the issue of animal sources of fibre not requiring proof of a beneficial physiological effect; and the effect of processing on fibre. Results and conclusion Unless all countries accept (or do not accept) that carbohydrate polymers with 3–9 monomeric units are dietary fibre, there will be two, rather than one definition. Again, if each country has its own criteria as to the physiological benefits of fibre and how to verify those benefits there will be as many “definitions” of fibre as there are effects accepted by all the member states. Given the importance to consumers, food companies, researchers, and regulatory agencies in having one definition, it is incumbent on all of us in the field to work toward that end.

We investigated the effects of dietary fiber (DF) supplementation in normal or low crude protein (CP) diets on reproductive performance and nitrogen (N) utilization in primiparous gilts. In total, 77 Landrace × Yorkshire pregnant gilts were randomly allocated to four dietary treatments in a 2 × 2 factorial design. The groups comprised 1) equal intake of normal CP (12.82% and 0.61% total lysine), 2) low CP (LP) (10.53% and 0.61% total lysine), and 3) with or 4) without DF supplementation (cellulose, inulin, and pectin in a 34:10:1 ratio). A low-protein diet during gestation significantly reduced daily weight gain from days 91 to 110 of pregnancy (-162.5 g/d, P = 0.004). From N balance trials conducted at days 35 to 38, 65 to 68, and 95 to 98 of pregnancy, DF addition increased fecal N excretion at days 65 to 68 (+24.1%) and 95 to 98 (+13.8%) of pregnancy (P < 0.05) but reduced urinary N excretion (P < 0.05), resulting in greater N retention at each gestational stage. DF increased fecal microbial protein levels and excretion during gestation. An LP diet also reduced urinary N excretion at different gestational stages. An in vitro fermentation trial on culture media with nonprotein N urea and ammonium bicarbonate (NH4HCO3) as the only N sources revealed that microbiota derived from feces of gestating gilts fed the high DF diet exhibited a greater capacity to convert nonprotein N to microbial protein. Microbial fecal diversity, as measured by 16S rRNA sequencing, revealed significant changes from DF but not CP diets. Gilts fed an LP diet had a higher number of stillbirths (+0.83 per litter, P = 0.046) and a lower piglet birth weight (1.52 vs. 1.37 kg, P = 0.006), regardless of DF levels. Collectively, DF supplementation to gestation diets shifted N excretion from urine to feces in the form of microbial protein, suggesting that the microbiota had a putative role in controlling N utilization from DF. Additionally, a low-protein diet during gestation negatively affected the litter performance of gilts.

Non-digestible oligosaccharides (NDO) and polysaccharides (NDP) occur naturally in many plants, mainly fruits, vegetables and whole grains. They resist hydrolysis and absorption in the human alimentary system and are partially or completely fermented by the colonic microfl ora in the large intestine. As such, these carbohydrates are part of a broad class of car-bohydrate-based compounds called dietary fi bre. NDO and NDP exhibit a variety of chemi-cal and physiological properties.It is the purpose of this chapter to provide an overview of the most important oligosac-charides and polysaccharides that are classifi ed as dietary fi bre, to describe their occurrence and structures, various physiological effects (both at a local and a systemic level) and the scientifi c evidence for these effects. The evidence for the health effects associated with these physiological effects will also be discussed. Finally, some food delivery systems for specifi c and general use will be described.As a general guide for this review, the primary elements of a recent dietary fi bre defi nition developed by an ad hoc AACC task force are used. These primary elements include being made up of edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine. Further, the compounds being included in the defi ni-tion of dietary fi bre should provide benefi cial physiological health effects, such as laxation, and/or blood glucose attenuation, and/or blood cholesterol attenuation.Fibres are an integral part of the foodstuffs that humans consume on a daily basis, and the main food sources in which these fi bres occur are listed in Table 39.1. Nowadays, it is also possible to enhance the fi bre content of food products by the addition of suitable fi bre sources (e.g. inulin or hydrolysed guar gum are suitable for this application). Adding fi bres with the desired properties offers the opportunity of increasing the physiological value of these food-stuffs.

Les fibres alimentaires : déterminants physico-chimiques, définition, aspects analytiques et physiologiques

New dietary fibre content results for cereals in the Nordic countries using AOAC 2011.25 method