Soaking in lactic acid lowers the phytate-phosphorus content and increases the resistant starch in wheat and corn grains

Adaptation of an in-vitro digestion model with different zinc-supplementation strategies on nutrient degradation of piglets

In-vitro studies are widely used in nutrition research. Two major challenges using in-vitro models in animal nutrition research are the individual adaptation of in-vitro digestion models to varying physiological conditions and small digesta output limiting sample material for further analysis. Since several years, the use of zinc in animal production has been legally reduced to control zinc emissions. Earlier, zinc doses around 3000 mg/kg diet were used to prevent post-weaning diarrhea and promote growth in weaning piglets. The first aim of this study was to adapt an in-vitro digestion system for piglets with increased sample output. The second aim was to study the effect of a titanium-bound zinc source at legal dietary inclusion levels on nutrient degradation in an in-vitro digestion model. The experiment was conducted in a 2x2 factorial design incubating 2 different feeds (1. control feed: a commercial piglet diet containing 75 mg zinc per kg diet and 2. treatment feed: control feed with 50 mg of a titanium-bound zinc oxide) in in-situ digestion bags in the Ankom Daisy® incubator with or without digestive enzymes (pepsin, pancreatic enzymes and bile salts). Residuals of incubated feed were analyzed for crude ash, crude protein and starch. The addition of pepsin, pancreatic enzymes and bile salts significantly increased organic matter, crude protein and starch degradation from the digested feed, therefore making the distinction of nutrient disappearance due to enzyme activity versus due to dissolution possible. In conclusion we established an in-vitro digestion model to evaluate the effect of addition of a new zinc source on the enzymatic digestion in piglets. However, addition of the new zinc source did not significantly improve nutrient degradation in the in-vitro digestion model.

Treatment of corn with lactic acid delayed in vitro ruminal degradation without compromising fermentation: a biological and morphological monitoring study

Grain processed by lactic acid (LA) is known to improve ruminant growth and health. However, the exact mechanism regarding rumen hydrolysis of LA-treated grain is still ambiguous. This experiment was designed to compare the effects of 5% LA treatment on the trophic and morphological variations in corn and to discover the alternations in ruminal hydrolysis between LA-treated and untreated corn macroscopically and microscopically using in vitro fermentation method. The results showed that, compared with untreated corn (CN), corn treated with 5% LA for 48 h (CNLA) experienced a decrease in the dry matter, albumin fraction, aNDFom, and water-soluble carbohydrate content but an increase in the resistant starch content. The in vitro fermentation showed that the pH of CNLA was higher, but dry matter disappearance was lower than that of CN. Most of the fermentation indices were unaffected, except for decreased iso-butyrate and iso-valerate. The abundances of total bacteria, Prevotella spp., Streptococcus bovis, and Selenomonas ruminantium were higher, but those of Ruminococcus flavefaciens and Ruminococcus albus were lower in CNLA than in CN. There were differences in the scanning electron micrographs between CNLA and CN after 3 h of fermentation. This study suggests that treating corn with LA for 48 h can induce changes in its nutrient composition and alter the bacterial flora during subsequent in vitro fermentation. These changes appeared to be crucial contributors to the beneficial effects observed in rumen fermentation.

Sprouts as probiotic carriers: A new trend to improve consumer nutrition

Over the past few decades, efforts to eradicate hunger in the world have led to the generation of sustainable development goals to reduce poverty and inequality. It is estimated that the current coronavirus pandemic could add between 83 and 132 million to the total number of undernourished people in the world by 2021. Food insecurity is a contributing factor to the increase in malnutrition, overweight and obesity due to the quality of diets to which people have access. It is therefore necessary to develop functional foods that meet the needs of the population, such as the incorporation of sprouts in their formulation to enhance nutritional quality. Germination of grains and seeds can be used as a low-cost bioprocessing technique that provides higher nutritional value and better bioavailability of nutrients. Consequently, the manuscript describes relevant information about the germination process in different seeds, the changes caused in their nutritional value and the use of techniques within the imbibition phase to modify the metabolic profiles within the sprouts such as inoculation with lactic acid bacteria and yeasts, to generate a functional symbiotic food.

Optimizing nitrogen fertilizer amount for best performance and highest economic return of winter wheat under limited irrigation conditions

Inappropriate water and fertilizer management can lead to unstable crop yields. Excessive fertilization can potentially cause soil degradation and nitrogen (N) leaching. The aim of this study was to explore the optimal N application rate on two wheat varieties with different nitrogen responding under limited water irrigation at three experimental sites in the Piedmont plain of the Taihang Mountains, China. A two-year field experiment was conducted to explore the effects of five N application rates (N0, N120, N180, N240, and N300) on winter wheat growth, leaf area index, aboveground biomass, grain yield, grain N accumulation, and net return. The results showed that N application rate significantly affected leaf area index, aboveground biomass, grain yield, and harvest index. Variety and variety × N rate interactions had a significant effect on few indicators. Compared with N0, N180 improved leaf area index, aboveground biomass, grain yield, and grain N accumulation. Compared with N240 and N300, N180 increased the harvest index and N harvest index, without significantly reducing grain yield or grain N accumulation, while enhancing a higher N use efficiency. Fertilizers applied in the ranges of 144.7-212.9 and 150.3-247.0 kg ha-1 resulted in the highest net return for the KN199 and JM585 varieties, respectively. Our study provides a sound theoretical basis for high-efficiency fertilizer utilization in sustainable winter wheat production in the Piedmont plains of the Taihang Mountains of China.

Short-, medium-, and long-chain fatty acid profiles and signaling is responsive to dietary phytase and lactic acid treatment of cereals along the gastrointestinal tract of growing pigs

Dietary and microbially derived fatty acids (FA) play important roles in gut mucosal inflammatory signaling, barrier function, and oxidative stress response. Nevertheless, little information is available about gastrointestinal FA profiles and receptor distribution in pigs, especially for long-chain FA (LCFA). Therefore, the present pilot study aimed to (1) investigate the gastrointestinal FA profiles; (2) link the luminal FA profiles to the mucosal expression of genes related to FA sensing and signaling; and (3) assess potential dietary effects on gut and systemic lipid metabolism in pigs. Gut, liver, and serum samples were obtained from barrows (13.1 ± 2.3 kg) fed diets containing either phytase (500 phytase units/kg diet) or cereals treated with 2.5% lactic acid (LA; n = 8/diet) for 18 d. Results showed gut regional and diet-related differences in luminal FA profiles and mucosal receptor expression, whereas diet little affected hepatic expression levels and serum lipids. Short-chain fatty acids (SCFA) increased from stomach, jejunum, and ileum to the cecum (P < 0.05), whereas LCFA were higher in stomach, cecum, and colon than in jejunum and ileum (P < 0.05). LA-treated cereals enhanced cecal acetate and butyrate, whereas phytase and LA treated cereals decreased the LCFA by 35.9% and 14.4%, respectively (P < 0.05). Gut regional differences suggested stronger signaling via FFAR1 expression in the ileum, and via FFAR2, FFAR4, and HCAR1 expression in cecum and colon (P < 0.05). Expression of AMPK, FASN, PPARG, SREBP1, and SREBP2 was higher in the cecum and colon compared with the small intestine (P < 0.05), with stronger sensing via FASN and SREBP2. Phytase decreased expression of FFAR2 and FFAR4, whereas it increased that of FFAR3 and MCT1 in the cecum (P < 0.05). LA-treated cereals raised cecal expression of FFAR3 and HCAR1 (P < 0.05). Pearson's correlations (|r| > 0.35; P < 0.05) supported that FA receptor- and nuclear transcription factor-dependent pathways were involved in the mucosal regulation of gut incretin expression but differed across gut regions. In conclusion, results support regional differences in SCFA, lactate and LCFA sensing and absorption capacities in the small and large intestines of pigs. Effects of phytase and the LA-treated cereals on intestinal FA levels and signaling can be explained by differences in nutrient flows (e.g., phosphorus and carbohydrate fractions). This overview provides a solid basis for future intestinal FA sensing in pigs.

Effect of polyaspartic acid and different dosages of controlled-release fertilizers on nitrogen uptake, utilization, and yield of maize cultivars

The effects of polyaspartic acid and different controlled-release fertilizers with urea on dry matter accumulation and distribution, nitrogen absorption and accumulation, and the activities of enzymes involved nitrogen metabolism and yield of corn were studied by using xianyu (XY688), a maize nitrogen efficient cultivar, and Jifeng NO.2 (JF2), a maize nitrogen-inefficient cultivar, as experimental materials and through random blocks experimental design in 2019. For XY688, polyaspartic acid chelated nitrogen fertilizer (PASPN) had the highest yield, which was 21.34% higher than N0 treatment. For JF2, it also had the highest yield under PASPN combined urea treatment, which was 23.44% higher than N0 (no nitrogen fertilizer), and JF2 had a 9.7% lower yield under XY688 treatment. For XY688, PASPN treatment had the largest nitrogen uptake in grain, up to 3.14 kg/hm², and PASPN treatment increased 17.4% compared with N0. For JF2, grain nitrogen uptake was also the highest under PASPN treatment, which was significantly different from other treatments. Nitrogen uptake was 3.16 kg/hm², which increased 37.4% compared with N0. Compared with JF2, XY688 showed higher nitrogen uptake efficiency, nitrogen utilization efficiency, and partial nitrogen productivity. For XY688, the highest nitrogen absorption efficiency was SU3 (slow-release urea and ordinary urea) treatment (0.36 kg/kg). The partial nitrogen productivity and harvest index of PASPN treatment were the highest and significantly different from other treatments. The partial nitrogen productivity of PASPN treatment was 57.02 kg/kg. These results can provide help for the further researches of the rational utilization and absorption of nitrogen fertilizer.

Dietary Phytase- and Lactic Acid-Treated Cereals Caused Greater Taxonomic Adaptations than Functional Adaptations in the Cecal Metagenome of Growing Pigs

Phosphorus (P) is an essential nutrient for the gut bacteria and the host. Nevertheless, little information exists that indicates to what extent an improved level of P availability in the small intestine leads to functional adaptations in bacterial metabolic pathways in the large intestine. Therefore, we investigated the changes in the taxonomic and functional bacterial metagenome in cecal digesta of growing pigs fed diets containing phytase and/or cereals treated with 2.5% lactic acid (LA) for 19 days (n = 8/diet) using shotgun metagenome sequencing. The phytase supplementation resulted in strikingly distinct bacterial communities, affecting almost all major bacterial families, whereas functional changes were less dramatic among the feeding groups. While phytase treatment decreased predominant Prevotellaceae levels, it seemed that Clostridiaceae, Ruminococcaceae, and Lachnospiraceae filled the opening metabolic niches (P < 0.05). The LA-treated cereals mediated reduced levels of Bacteroidaceae and increased levels of Veillonellaceae, but those results were mainly seen when the cereals were fed as a single treatment (P < 0.05). In association with the taxonomic alterations, phytase caused changes within the major functional pathways corresponding to amino acid metabolism; translation; membrane transport; folding, sorting, and degradation; and energy metabolism, whereas the LA treatment of cereals resulted in decreased enzymatic capacities within the carbohydrate metabolism and energy metabolism pathways (P < 0.05). Metabolic dependencies corresponding to the starch and sucrose metabolism, glycolysis/gluconeogenesis, and citrate cycle pathways were indicated by diet-associated changes in enzymatic capacities related to short-chain fatty acid, methane, vitamin, and bacterial antigen synthesis. Accordingly, the present results support the idea of the importance of the availability of intestinal P for bacterial metabolism. However, the functional profiles were less different than the taxonomic profiles among the dietary treatment results, indicating a certain degree of metabolic plasticity within the cecal metagenome.IMPORTANCE Dietary strategies (e.g., phytase supplementation and lactic acid [LA] treatment of cereals) used to improve the availability of phytate-phosphorus (P) from pig feed reduce the amount of P flowing into the large intestine, whereas LA treatment-induced changes in nutrient fractions alter the substrate being available to the microbiota. In ruminants, lower intestinal P availability compromises the fibrolytic activity of the microbiome. Here, we report that the functional capacities were less dramatically affected than the taxonomic composition by phytase-supplemented and LA-treated cereals. The bacterial community appeared to be partly capable of functionally compensating for the altered flow of P by replacing taxa with higher P needs by those with lower P needs. Therefore, by acting as mucosal immune stimulants, alterations in microbiota-associated molecular patterns (MAMPs) due to the taxonomic shifts may play a greater role for host physiology and health than functional differences caused by differing intestinal P availabilities, which merits further research.

Novel strategies for degradation of aflatoxins in food and feed: A review

Aflatoxins are toxic secondary metabolites mainly produced by Aspergillus fungi, posing high carcinogenic potency in humans and animals. Dietary exposure to aflatoxins is a global problem in both developed and developing countries especially where there is poor regulation of their levels in food and feed. Thus, academics have been striving over the decades to develop effective strategies for degrading aflatoxins in food and feed. These strategies are technologically diverse and based on physical, chemical, or biological principles. This review summarizes the recent progress on novel aflatoxin degradation strategies including irradiation, cold plasma, ozone, electrolyzed oxidizing water, organic acids, natural plant extracts, microorganisms and enzymes. A clear understanding of the detoxification efficiency, mechanism of action, degradation products, application potential and current limitations of these methods is presented. In addition, the development and future perspective of nanozymes in aflatoxins degradation are introduced.

Maturational Changes Alter Effects of Dietary Phytase Supplementation on the Fecal Microbiome in Fattening Pigs

Age-related successions in the porcine gut microbiome may modify the microbial response to dietary changes. This may especially affect the bacterial response to essential nutrients for bacterial metabolism, such as phosphorus (P). Against this background, we used phytase supplementation (0 or 650 phytase units/kg complete feed) to alter the P availability in the hindgut and studied the dietary response of the fecal bacterial microbiome from the early to late fattening period. Fecal DNA were isolated after 0, 3, 5 and 10 weeks and the V3-V4 region of the 16S rRNA gene was sequenced. Permutational analysis of variance showed distinct bacterial communities for diet and week. Alpha-diversity and taxonomy indicated progressing maturation of the bacterial community with age. Prevotellaceae declined, whereas Clostridiaceae and Ruminococcaceae increased from weeks 0 to 3, 5, and 10, indicating changes in fiber-digesting capacities with age. Phytase affected all major bacterial taxa but reduced species richness (Chao1) and diversity (Shannon and Simpson). To conclude, present results greatly support the importance of available P for bacterial proliferation, including fibrolytic, lactic acid- and butyrate-producing genera, in pigs. Results also emphasize the necessity to assess bacterial responses to dietary manipulation at several time points throughout the fattening period.

Dietary Phytase and Lactic Acid-Treated CerealGrains Differently Affected Calcium and PhosphorusHomeostasis from Intestinal Uptake to SystemicMetabolism in a Pig Model

High intestinal availability of dietary phosphorus (P) may impair calcium (Ca)homeostasis and bone integrity. In the present study, we investigated the effect of phytasesupplementation in comparison to the soaking of cereal grains in 2.5% lactic acid (LA) on intestinalCa and P absorption; intestinal, renal, and bone gene expression regarding Ca and P homeostasis;bone parameters; and serum levels of regulatory hormones in growing pigs. Thirty-two pigs wererandomly assigned to one of four diets in a 2 × 2 factorial design in four replicate batches for 19days. The diets comprised either untreated or LA-treated wheat and maize without and withphytase supplementation (500 phytase units/kg). Although both treatments improved the Pbalance, phytase and LA-treated cereals differently modulated gene expression related to intestinalabsorption, and renal and bone metabolism of Ca and P, thereby altering homeostatic regulatorymechanisms as indicated by serum Ca, P, vitamin D, and fibroblast growth factor 23 levels.Moreover, phytase increased the gene expression related to reabsorption of Ca in the kidney,whereas LA-treated cereals decreased the expression of genes for osteoclastogenesis in bones,indicating an unbalanced systemic availability of minerals. In conclusion, high intestinalavailability of dietary P may impair Ca homeostasis and bone integrity.

Alterations of the Viable Ileal Microbiota of the Gut Mucosa-Lymph Node Axis in Pigs Fed Phytase and Lactic Acid-Treated Cereals

The gut-lymph node axis is a critical player in the symbiotic relationship between gut microbiota and the host. However, little is known about the impact of diet-related bacterial shifts in the gut lumen on bacterial translocation into lymph nodes. Here, we (i) characterized changes in the viable microbiota composition along the ileal digesta-mucosa-lymph node axis and (ii) examined the effect of dietary phytase supplementation and lactic acid (LA) soaking of cereals on the bacterial taxonomy along this axis, together with their effect on the mucosal expression of innate immune and barrier function genes in pigs (n = 8/diet). After 18 days on diets, ileal digesta, mucosa, and ileocecal lymph nodes (ICLNs) were collected for RNA isolation and 16S rRNA-based high-resolution community profiling. Bacterial communities were dominated by Lactobacillaceae and Clostridiaceae, with clearly distinguishable profiles at the three sampling sites. Specific bacterial subsampling was indicated by enrichment of the ICLNs with Lactobacillaceae, Lachnospiraceae, Veillonellaceae, and Methanobacteriaceae and less Clostridiaceae, Pasteurellaceae, Helicobacteraceae, and Enterobacteriaceae compared to that of the mucosa. LA treatment of cereals reduced proteolytic taxa in the lumen, including pathobionts like Helicobacteraceae, Campylobacteraceae, and Fusobacteriaceae When combined, phytase- and LA-treated cereals largely increased species richness, while the single treatments reduced Actinobacteria and Bacteroidetes in ICLNs and increased mucosal MUC2 expression. In contrast, phytase reduced mucosal CDH1 expression, indicating altered barrier function with potential effects on bacterial translocation. Overall, both treatments, although often differently, changed the viable microbiome along the digesta-mucosa-lymph node axis in the ileum, probably due to altered substrate availability and microbial-host interactions.IMPORTANCE A host's diet largely determines the gut microbial composition and therefore may influence bacterial translocation into ICLNs. Due to its importance for cell metabolism, the intestinal phosphorus availability, which was modified here by phytase and LA treatment of cereals, affects the intestinal microbiota. Previous studies mainly focused on bacteria in the lumen. The novelty of this work resides mainly in that we report diet-microbe effects along the digesta-mucosa-ICLN axis and linked those effects to mucosal expression of barrier function genes as crucial components for host health. Lymph nodes can serve as reservoir of pathobionts; therefore, present diet-microbiome-host interactions have implications for food safety.

Lactic Acid Treatment of Cereals and Dietary Phytase Modified Fecal Microbiome Composition Without Affecting Expression of Virulence Factor Genes in Growing Pigs

Besides the major nutrients, phosphorus (P) is an essential mineral for both the host animal and the porcine gut microbiota. Different strategies including phytase supplementation and more recently lactic acid (LA) are used to enhance the P availability from cereals in pig diets; however, their impact on the gut microbiota has been rarely related to fecal shedding of opportunistic pathogens. The present study investigated the effect of phytase supplementation and the treatment of dietary cereals with 2.5% LA on the fecal microbiome composition of metabolic active bacteria and expression of virulence factor genes of enterotoxigenic Escherichia coli and Clostridium perfringens in growing pigs. Phytase supplementation reduced the fecal abundance of the most abundant Lactobacillaceae family, whereas the LA-treatment of cereals had a stronger impact on the bacterial community, reducing amylolytic, pullulanolytic and hemicellulolytic Lactobacillaceae, Lachnospiraceae and Ruminococcaceae as well as the fecal bacterial species richness (Chao1) and diversity (Shannon index). Mainly the family Clostridiaceae benefited from the decline in the aforementioned families, being enriched by both dietary treatments. Multigroup data integration using sparse partial least squares-discriminant analysis showed that among the most discriminative operational taxonomic units (OTU) especially two unclassified Clostridiaceae-OTUs, one Prevotella copri-like OTU and one OTU within the vadinCA11 group were associated with calcium and P levels but were negatively linked with complex carbohydrates in feces. Heat-stable toxin A (Sta) of enterotoxigenic E. coli and Stx2e of Shiga-toxin producing E. coli were expressed in feces but were similar among feeding groups. Without modifying the total bacterial gene copies and virulence factor expression of E. coli, both dietary phytase supplementation and LA-treatment of cereals drastically altered the bacterial community composition in pig feces. Results thereby allowed for the characterization of bacterial nutrient dependencies, indicating a link between fecal P availability, complex carbohydrate composition and alterations in the predominant genera.