ABSTRACT Reported avocado dietary fiber (DF) content and composition are inconsistently reported, particularly during ripening. Thus, this study aimed to characterize the amount and type of DF in Hass avocados and evaluate DF changes during ripening. Unripe (day 0), ripe (day 5), and overripe (day 12) Hass avocados were freeze-dried and defatted. DF was analyzed using non-starch polysaccharide (NSP) enzymatic-chemical methods. Per 100g of as-is avocado, unripe contained 3.96g total DF, ripe 3.68g, and overripe 3.26g. In ripe avocados, DF comprised 43% soluble (SDF) and 57% insoluble dietary fiber (IDF). SDF consisted primarily of rhamnogalacturonan-1 and arabinan pectins, while IDF was predominantly cellulose (32%), hemicelluloses (23%), and lignin (2%). Total DF decreased with ripening, with pectin undergoing solubilization and depolymerization, while cellulose and hemicelluloses remained stable. These findings are important as dietary fibers differentially influence intestinal microbial fermentation and health benefits.

Probiotics, prebiotics, and other biotic substances are not only effective ways to promote a healthy gastrointestinal tract, an effective immune system, and the overall health of humans, but also in agricultural and companion animals. Because key differences exist in regard to gastrointestinal tract anatomy and physiology, dietary management and feeding strategy, and disease susceptibility, however, biotic types and amounts often differ according to host species and life stage. Despite these differences, the literature demonstrates the value of biotics in agricultural and companion animal species. While high variability in responsiveness and efficacy has been reported, biotic substances may be effectively used to improve digestion, reduce morbidity, increase growth rate and/or efficiency in agricultural animals and promote gastrointestinal health and immune response in companion animals. As the oversight of antibiotic use intensifies, the population density of animals and humans increases, and production strategies of agricultural animals are more heavily scrutinized, the importance of biotics and other health promotors will continue to increase in the future. To date, the effects of animal biotic use have focused primarily on the farm, home, or veterinary clinic. In the future, their impact must be viewed on a larger scale. As global "One Health" approaches seek to reduce antimicrobial use and resistance and there are increasing demands for sustainable and safe food production, biotics will continue to be an important part of the solution. As knowledge of gastrointestinal microbiomes grows and the biotic field develops, more targeted and effective strategies for health promotion in these species are expected. At the 2023 International Scientific Association for Probiotics and Prebiotics meeting, experts were invited to participate in a discussion group focused on "The Use of Probiotics and Prebiotics in Agricultural and Companion Animals". This review reports the outcomes of that discussion, including the documented use of probiotics, prebiotics, and other biotic substances to promote health or treat disease in agricultural and companion animals, provide implications of animal biotic use on human health, and provide perspective on how scientific advances may impact the development and improvement of biotics in the future.

A new generation of standard reference diets (SRDs) is essential to enhance the integrity of research associated with the use of laboratory animal models in the study of human disease. Support for the value of this fundamental facet of experimental methodology is provided via a historical overview, an assessment of current status, and the advancements and opportunities that will be realized through further development and routine use. An outline of the extensive investment in animal nutrition research by National Institutes of Health during the past 30 y is presented with specific reference to rodent animal models and standardization in dietary methodology. Timely recommendations for renewed action that revitalize and expand the use of SRDs in rodents and other models, such as zebrafish, are provided with the aim of achieving more rigor, transparency, replicability, interpretability, and integrity in preclinical and translational animal model-based research. Ultimately, the benefits of these efforts will be fulfilled through expeditious development of prophylactic and therapeutic approaches for human diseases.

Canine copper nutrition has received increased attention due to recent reports of apparent copper-associated hepatitis in the USA and European Union. In order to properly address the need to modify the U.S. National Research Council and Association of American Feed Control Officials canine copper recommendations that will have implications for all dogs, it is important to understand the complexities of copper metabolism, confounding variables affecting copper status, and the available research on this topic in dogs. Recent trends in consumer preference for dog diets, supplements, and functional treats introduce another layer of complexity, as most ingredients used in these formulations provide vastly different proportions of essential nutrients, thus resulting in great variation in nutrient profiles available to the animal. Although controlled research addressing copper metabolism in dogs is limited, there are lessons to be learned from other monogastric species as well as canine case studies that can provide a base for increasing knowledge to address this issue. Copper metabolism and status in animals is affected by a multitude of factors including absorption, storage, excretion, and nutrient interactions. Given its vital role in many physiological processes, it is important that both nutritional deficiencies and toxicities be avoided. Additionally, another challenge for proper copper nutrition in dogs is the known genetic predispositions of some breeds for copper storage and excretion abnormalities. Therefore, it is imperative that veterinarians, nutritionists, and pet food manufacturers collaborate with the shared goal of providing dog food options that supply the essential nutrients at adequate concentrations to support an active and healthy life. Many questions remain regarding copper metabolism and proper diet formulation for dogs. Future research efforts should focus on discovering reliable, non-invasive methods for evaluating canine copper status, a deeper understanding of genetic predispositions of certain breeds, increased knowledge of copper contributions from various ingredients, and the role of unpredictable physiological stressors on copper metabolism.

The Dietary Fiber (fiber) Terminology Roundtable was organized to address crucial issues concerning current definitions of dietary fiber and the pressing need to resolve inconsistencies and ambiguities in fiber terminology. This publication captures valuable insights and diverse perspectives from a multidisciplinary group of experts who span research areas, including fiber and carbohydrate research in human health, fiber analysis and methodology, and food and nutrition ontology development and application, as well as food composition data and public health. Although health is a critical concern, the use of the word "health" here is directly tied to its intrinsic role in regulatory definitions of dietary fiber. The presentations supported the view of dietary fiber as an essential food component with significant potential to improve health, underscoring the need for clarity in language and communication. Additionally, the concept of a systematic ontological framework was introduced as a highly valuable and most suitable solution to facilitate clear communication about fiber in research, education, healthcare, and industry. As a result, a Dietary Fiber Ontology Working Group has been formed, and the collective expertise within the group will contribute to the creation of an open-access fiber ontology. This effort aims to not only address educational aspects but also support the identification of fiber-related health outcomes and the underlying mechanisms responsible for biological effects.

For over six decades, nutritional science has provided well-developed, peer-reviewed nutrient recommendations to support the health of dogs and cats. These guidelines are updated based on new scientifically valid research and appropriate peer-review. Recent regulatory and scientific positions around health issues have resulted in strong opinions and desires for rapid regulatory action surrounding mineral nutrition, but with limited and conflicting scientific evidence. Pet Food Institute nutrition experts have come together to jointly author an article on the complexities of establishing mineral tolerances of dogs and cats to illustrate the limitations in defining mineral tolerances. This discussion covers how mineral requirements were determined, including the opportunities and pitfalls encountered. Scientific councils must review and clarify any proposed changes in conducting mineral nutrition research that might impact complete and balanced foods and surrounding regulations. It is important to clarify the multiple issues in mineral nutrition research and the necessity for thorough evaluation of data while avoiding arbitrary and potentially harmful guidelines.

The Dietary Fiber (fiber) Terminology Roundtable was organized to address crucial issues concerning current definitions of dietary fiber and the pressing need to resolve inconsistencies and ambiguities in fiber terminology. This publication captures valuable insights and diverse perspectives from a multidisciplinary group of experts who span research areas, including fiber and carbohydrate research in human health, fiber analysis and methodology, and food and nutrition ontology development and application, as well as food composition data and public health. Although health is a critical concern, the use of the word “health” here is directly tied to its intrinsic role in regulatory definitions of dietary fiber. The presentations supported the view of dietary fiber as an essential food component with significant potential to improve health, underscoring the need for clarity in language and communication. Additionally, the concept of a systematic ontological framework was introduced as a highly valuable and most suitable solution to facilitate clear communication about fiber in research, education, healthcare, and industry. As a result, a Dietary Fiber Ontology Working Group has been formed, and the collective expertise within the group will contribute to the creation of an open-access fiber ontology. This effort aims to not only address educational aspects but also support the identification of fiber-related health outcomes and the underlying mechanisms responsible for biological effects.

Nicola M McKeown and colleagues advocate for the importance of translating the health impact of high fibre diets to patients and clients, with emphasis placed on incorporating a variety of plant based foods to achieve dietary fibre recommendations

It has been nearly 31 years since the International Symposium on Forage Cell Wall Structure and Digestibility was held in Madison, WI. The text resulting from that symposium, first published in 1993, has been an invaluable resource for animal and plant scientists alike but, unfortunately, has yet to be updated. Symposium organizers recognized that there was "a critical lack of information on the chemistry of the cell walls of forage plants and especially how this chemistry relates to digestibility and absorption of the materials and how the digestibility can be improved through plant breeding". They proceeded to organize an excellent symposium that covered nearly every aspect of that broad topic. Whereas "fiber" (plant cell wall) always has been a mainstay in ruminant animal feeding, its importance in the areas of human and non-ruminant animal nutrition has now been realized as indicated by the extensive scientific literature published on the topic since the time of the symposium, and by the fact that dietary fiber is now considered an "essential nutrient" for the human. In this presentation, the components of the plant cell wall will be discussed and their organization within the plant defined. Their relationship to the gut microbiota will be highlighted as will those factors critical in determining accurate fiber concentrations in forages and fibrous ingredients using the latest fiber methodologies. Rather than being viewed simply as "roughage" or as "filler" or as an "anti-nutritional factor", cell walls now have a prominent role in all of animal and human nutrition, so understanding their characteristics at all levels becomes all the more important.

Human intestinal enzymes do not hydrolyze nondigestible carbohydrates (NDCs), and thus, they are not digested and absorbed in the small intestine. Instead, NDCs are partially to completely fermented by the intestinal microbiota. Select NDCs are associated with health benefits such as laxation and lowering of blood cholesterol and glucose. NDCs provide functional attributes to processed foods, including sugar or fat replacers, thickening agents, and bulking agents. Additionally, NDCs are incorporated into processed foods to increase their fiber content. Although consumption of NDCs can benefit health and contribute functional characteristics to foods, they can cause gastrointestinal symptoms, such as flatulence and bloating. As gastrointestinal symptoms negatively affect consumer well-being and their acceptance of foods containing NDC ingredients, it is crucial to consider tolerance when designing food products and testing their physiological health benefits in clinical trials. This perspective provides recommendations for the approach to assess gastrointestinal tolerance to NDCs, with a focus on study design, population criteria, intervention, comparator, and outcome. Special issues related to studies in children and implications for stakeholders are also discussed. It is recommended that the evaluation of gastrointestinal tolerance to NDCs be conducted in randomized, blinded, controlled crossover studies using standard gastrointestinal questionnaires, with attention to study participant background diets, health status, lifestyle, and medications.

The fiber component of the diet is the major food source for the intestinal microbiota of swine. Included are traditional insoluble (e.g., cellulose) and soluble (e.g., pectin) dietary fibers, resistant starches (four types), and oligosaccharides (some of which are “prebiotics”). Fiber constituents are found both in the primary and secondary cell walls of plants, but some are found in non-cell wall structures as well. In cereals, cell walls consist of a reinforced multi-component matrix of cross-linked polymers (acidic xylans, arabinoxylans, glucomannans) in which a network of cellulose microfibrils is embedded. Proteins form a second network in the matrix, and lignin and phenolic acids may be covalently linked to the matrix polysaccharides. In addition, whole grains have considerable amounts of resistant starch. Physical processing and cooking have a major effect on the chemical composition and subsequent utilization of the whole grain. Techniques are available to quantify both the insoluble and soluble fibers present in swine diets. Solubility often impacts the location of fermentation within the swine gastrointestinal tract, and solubility often, but not always, reflects fermentation potential. Other important attributes of fiber include its viscosity/gel-forming capacity/water-holding capacity, and its fermentability. On the analytical front, considerable progress has been and continues to be made, with many AOAC-approved techniques currently available. In summary, dietary fiber is perhaps the most chemically complicated of any swine feed constituent, making its analysis difficult. Fibers, whether they be intrinsic and intact, isolated, chemically and (or) enzymatically synthesized, alternative, etc.represent the key foods for the swine intestinal microbiota, so a good understanding of their properties is critical to fully understand how to optimize their role in swine nutrition.

OBJECTIVE:The prebiotic fiber inulin has been studied in individuals undergoing hemodialysis (HD) due to its ability to reduce gut microbiota-derived uremic toxins. However, studies examining the effects of inulin on the gut microbiota and derived metabolites are limited in these patients. We aimed to assess the impact of a 4-week supplementation of inulin on the gut microbiota composition and microbial metabolites of patients on HD.DESIGN AND METHODS:In a randomized, double-blind, placebo-controlled, crossover study, twelve HD patients (55 ± 10 y, 50% male, 58% Black American, BMI 31.6 ± 8.9 kg/m2, 33% diabetes mellitus) were randomized to consume inulin [10 g/d for females; 15 g/d for males] or maltodextrin [6 g/d for females; 9 g/d for males] for 4 weeks, with a 4-week washout period. We assessed the fecal microbiota composition, fecal metabolites (short-chain fatty acids (SCFA), phenols, and indoles), and plasma indoxyl sulfate and p-cresyl sulfate.RESULTS:At baseline, factors that explained the gut microbiota variability included BMI category and type of phosphate binder prescribed. Inulin increased the relative abundance of the phylum Verrucomicrobia and its genus Akkermansia (P interaction = 0.045). Inulin and maltodextrin resulted in an increased relative abundance of the phylum Bacteroidetes and its genus Bacteroides (P time = 0.04 and 0.03, respectively). Both treatments increased the fecal acetate and propionate (P time = 0.032 and 0.027, respectively), and there was a trend toward increased fecal butyrate (P time = 0.06). Inulin did not reduce fecal p-cresol or indoles, or plasma concentrations of p-cresyl sulfate or indoxyl sulfate.CONCLUSIONS:A 4-week supplementation of inulin did not lead to major shifts in the fecal microbiota and gut microbiota-derived metabolites. This may be due to high variability among participants and an unexpected increase in fecal excretion of SCFA with maltodextrin. Larger studies are needed to determine the effects of prebiotic fibers on the gut microbiota and clinical outcomes to justify their use in patients on HD.

Traditional feed composition tables have been a useful tool in the field of animal nutrition throughout the last 70 yr. The objective of this paper is to discuss the challenges and opportunities associated with creating large feed ingredient composition tables. This manuscript will focus on three topics discussed during the National Animal Nutrition Program (NANP) Symposium in ruminant and nonruminant nutrition carried out at the American Society of Animal Science Annual Meeting in Austin, TX, on July 11, 2019, namely: 1) Using large datasets in feed composition tables and the importance of standard deviation in nutrient composition as well as different methods to obtain accurate standard deviation values, 2) Discussing the importance of fiber in animal nutrition and the evaluation of different methods to estimate fiber content of feeds, and 3) Description of novel feed sources, such as insects, algae, and single-cell protein, and challenges associated with the inclusion of such feeds in feed composition tables. Development of feed composition tables presents important challenges. For instance, large datasets provided by different sources tend to have errors and misclassifications. In addition, data are in different file formats, data structures, and feed classifications. Managing such large databases requires computers with high processing power and software that are also able to run automated procedures to consolidate files, to screen out outlying observations, and to detect misclassified records. Complex algorithms are necessary to identify misclassified samples and outliers aimed to obtain accurate nutrient composition values. Fiber is an important nutrient for both monogastrics and ruminants. Currently, there are several methods available to estimate the fiber content of feeds. However, many of them do not estimate fiber accurately. Total dietary fiber should be used as the standard method to estimate fiber concentrations in feeds. Finally, novel feed sources are a viable option to replace traditional feed sources from a nutritional perspective, but the large variation in nutrient composition among batches makes it difficult to provide reliable nutrient information to be tabulated. Further communication and cooperation among different stakeholders in the animal industry are required to produce reliable data on the nutrient composition to be published in feed composition tables.

BACKGROUND:Treatment guidelines for chronic idiopathic constipation (CIC) recommend an "increase in fiber intake" as a first-line therapy, but most epidemiologic studies fail to support an association between a high-fiber diet and a reduced risk of constipation. Furthermore, randomized controlled clinical studies show that most isolated fibers (e.g., supplements) are not different from placebo for a laxative effect, and several may be constipating.OBJECTIVES:The objective of this review was to compare the effects of two isolated fibers, coarse wheat bran and psyllium, on stool output and stool water content in patients with CIC. This review will also address misconceptions about fiber that are perpetuated by treatment guidelines.DATA SOURCES:A comprehensive literature review was conducted with the use of the Scopus, SciFinder, and PubMed scientific databases, limited to the previous 50 years (1968-2018; latest date included, December 31, 2018).CONCLUSIONS:In patients with CIC, nonfermented gel-forming psyllium was 3.4 times more effective than insoluble wheat bran for increasing stool output. Both psyllium and coarse wheat bran increased stool water content, a stool-softening effect, but finely ground wheat bran decreased stool water content, a stool-hardening effect.IMPLICATIONS FOR PRACTICE:It is a misconception that dietary fiber and all isolated fibers provide a laxative effect in patients with CIC. Our analysis suggests that treatment guidelines for CIC should make specific evidence-based recommendations as it pertains to fiber. To do otherwise takes the risk of perpetuating myth and misunderstanding and depriving patients of an effective therapy for CIC. A generic recommendation to "increase fiber intake" is akin to a recommendation to "increase pill intake" without regard to therapeutic or adverse effects.

Abstract Traditional feed composition tables have been a useful tool in the field of animal nutrition throughout the last 70 yr. The objective of this paper is to discuss the challenges and opportunities associated with creating large feed ingredient composition tables. This manuscript will focus on three topics discussed during the National Animal Nutrition Program (NANP) Symposium in ruminant and nonruminant nutrition carried out at the American Society of Animal Science Annual Meeting in Austin, TX, on July 11, 2019, namely: 1) Using large datasets in feed composition tables and the importance of standard deviation in nutrient composition as well as different methods to obtain accurate standard deviation values, 2) Discussing the importance of fiber in animal nutrition and the evaluation of different methods to estimate fiber content of feeds, and 3) Description of novel feed sources, such as insects, algae, and single-cell protein, and challenges associated with the inclusion of such feeds in feed composition tables. Development of feed composition tables presents important challenges. For instance, large datasets provided by different sources tend to have errors and misclassifications. In addition, data are in different file formats, data structures, and feed classifications. Managing such large databases requires computers with high processing power and software that are also able to run automated procedures to consolidate files, to screen out outlying observations, and to detect misclassified records. Complex algorithms are necessary to identify misclassified samples and outliers aimed to obtain accurate nutrient composition values. Fiber is an important nutrient for both monogastrics and ruminants. Currently, there are several methods available to estimate the fiber content of feeds. However, many of them do not estimate fiber accurately. Total dietary fiber should be used as the standard method to estimate fiber concentrations in feeds. Finally, novel feed sources are a viable option to replace traditional feed sources from a nutritional perspective, but the large variation in nutrient composition among batches makes it difficult to provide reliable nutrient information to be tabulated. Further communication and cooperation among different stakeholders in the animal industry are required to produce reliable data on the nutrient composition to be published in feed composition tables.

Background: Because of its chemical complexity, the estimation of dietary fiber content of feed and food materials is a difficult analytical challenge. Three major fiber analyses are conducted routinely in the United States including crude fiber (CF), detergent fiber, and total dietary fiber (TDF). Objective: Factors crucial to the successful measurement of dietary fibers are described and suggestions provided as to how to overcome potential analytical problems within assays. Methods: An accounting of methodological details that result in variation in fiber concentration values is presented along with suggestions as to how to decrease the variation. Results: CF analysis remains in use in the livestock feed and pet food industries for nutrition labeling purposes in spite of the fact that the analysis does not separate mammalian enzyme-digestible from indigestible carbohydrate components, and values obtained are usually 30-50% of the actual dietary fiber concentration. Detergent fiber methods quantify the insoluble dietary fibers (IDF) accurately, but not the soluble dietary fiber (SDF) components. TDF methods account for intrinsic and intact fibers, isolated and extracted fibers, and synthetic fibers found in feed and food ingredients and complete diet matrixes. Conclusions: The CF procedure should be abandoned as it fails to quantify fiber properly. Detergent analyses quantify IDF. TDF methods quantify both IDF and SDF. Highlights: Accurate dietary fiber quantification is essential given the role of fiber in health and well-being of animals and humans.

In recent years, it has become increasingly obvious that dietary fiber or nondigestible carbohydrate (NDC) consumption is critical for maintaining optimal health and managing symptoms of metabolic disease. In accordance with this, the US FDA released its first official definition of dietary fiber in 2016 for regulation of Nutrition and Supplement Facts labels. Included in this definition is the requirement of an isolated or synthetic NDC to produce an accepted physiologic health benefit, such as improved laxation or reduced fasting cholesterol concentrations, upon consumption. Even though NDC fermentation and production of short-chain fatty acids elicit many physiologic effects, including serving as a source of energy for colonocytes, curbing glycemic response and satiety, promoting weight loss, enhancing mineral absorption, reducing systemic inflammation, and improving intestinal health, the process of fermentation is not considered a physiologic endpoint. Instead, expensive and laborious clinical trials must be conducted and an accepted physiologic benefit observed. In this review, we discuss the physiologic importance of NDC fermentation through extensive examination of clinical evidence and propose that the degree of fermentability of an NDC, rather than the endpoints of a clinical trial, may be appropriate for classifying it as a dietary fiber.

A 2-day workshop organized by the National Institutes of Health and U.S. Department of Agriculture included 16 presentations focused on the role of diet in alterations of the gastrointestinal microbiome, primarily that of the colon. Although thousands of research projects have been funded by U.S. federal agencies to study the intestinal microbiome of humans and a variety of animal models, only a minority addresses dietary effects, and a small subset is described in sufficient detail to allow reproduction of a study. Whereas there are standards being developed for many aspects of microbiome studies, such as sample collection, nucleic acid extraction, data handling, etc., none has been proposed for the dietary component; thus this workshop focused on the latter specific point. It is important to foster rigor in design and reproducibility of published studies to maintain high quality and enable designs that can be compared in systematic reviews. Speakers addressed the influence of the structure of the fermentable carbohydrate on the microbiota and the variables to consider in design of studies using animals, in vitro models, and human subjects. For all types of studies, strengths and weaknesses of various designs were highlighted, and for human studies, comparisons between controlled feeding and observational designs were discussed. Because of the lack of published, best-diet formulations for specific research questions, the main recommendation is to describe dietary ingredients and treatments in as much detail as possible to allow reproduction by other scientists.

Recent data has supported a role for the gut microbiota in improving cognition and shaping behavior. Here, we assessed whether pectin, a soluble, fermentable fiber, could enhance learning and memory in mice. Two cohorts of young male C57B1/6 J mice, C1 (n = 20) and C2 (n = 20), were obtained from Jackson Laboratory and randomized to semi-purified AIN-93 M diets containing 5% pectin (n = 10) or cellulose (n = 10). After 16 weeks, learning and memory was assessed by Morris Water Maze (MWM) and microbiota composition was analyzed by 16S rRNA sequencing. Despite identical treatment, we observed differences in learning and memory abilities between cohorts, along with distinct microbiotas. In C1, pectin-fed mice spent a higher percentage of time in the target quadrant at the 24-h probe trial of the MWM versus cellulose-fed mice; in C2, no effect of pectin was observed. In both cohorts, UniFrac distance revealed significant differences in gut microbial communities between cellulose-fed and pectin-fed mice. UniFrac analysis also revealed significantly different bacterial communities between cohorts. Further analysis demonstrated that the microbial genera Oscillospira, Bilophila, and Peptostreptococcoceae were more abundant in C1 versus C2, and positively associated with distance from the platform during the 24-h probe test. These data support previous findings that differences in the gut microbiota may play a role in host response to a dietary intervention and could partly explain irreproducibility in psychological and behavioral experiments. Further research is needed to determine if a causal relationship exists.