This article summarizes the experimental knowledge on efficacy, possible modes of action, and aspects of application of phytogenic products as feed additives for swine and poultry. Phytogenic feed additives comprise a wide variety of herbs, spices, and products derived thereof, and are mainly essential oils. The assumption that phytogenic compounds might improve the palatability of feed has not yet been confirmed by choice-feeding studies. Although numerous studies have demonstrated antioxidative and antimicrobial efficacy in vitro, respective experimental in vivo evidence is still quite limited. The same applies to the supposition that phytogenic compounds may specifically enhance activities of digestive enzymes and nutrient absorption. Nevertheless, a limited number of experimental comparisons of phytogenic feed additives with antibiotics and organic acids have suggested similar effects on the gut, such as reduced bacterial colony counts, fewer fermentation products (including ammonia and biogenic amines), less activity of the gut-associated lymphatic system, and a greater prececal nutrient digestion, probably reflecting an overall improved gut equilibrium. In addition, some phytogenic compounds seem to promote intestinal mucus production. Such effects may explain a considerable number of practical studies with swine and poultry reporting improved production performance after providing phytogenic feed additives. In total, available evidence indicates that phytogenic feed additives may add to the set of nonantibiotic growth promoters for use in livestock, such as organic acids and probiotics. However, a systematic approach toward the efficacy and safety of phytogenic compounds used as feed additives for swine and poultry is still missing.

SummaryPhosphorus (P) is primarily stored in the form of phytates in plant seeds, thus being poorly available for monogastric livestock, such as pigs and poultry. As phytate is a polyanionic molecule, it has the capacity to chelate positively charged cations, especially calcium, iron and zinc. Furthermore, it probably compromises the utilization of other dietary nutrients, including protein, starch and lipids. Reduced efficiency of utilization implies both higher levels of supplementation and increased discharge of the undigested nutrients to the environment. The enzyme phytase catalyses the stepwise hydrolysis of phytate. In respect to livestock nutrition, there are four possible sources of this enzyme available for the animals: endogenous mucosal phytase, gut microfloral phytase, plant phytase and exogenous microbial phytase. As the endogenous mucosal phytase in monogastric organisms appears incapable of hydrolysing sufficient amounts of phytate-bound P, supplementation of exogenous microbial phytase in diets is a common method to increase mineral and nutrient absorption. Plant phytase activity varies greatly among species of plants, resulting in differing gastrointestinal phytate hydrolysis in monogastric animals. Besides the supplementation of microbial phytase, processing techniques are alternative approaches to reduce phytate contents. Thus, techniques such as germination, soaking and fermentation enable activation of naturally occurring plant phytase among others. However, further research is needed to tap the potential of these technologies. The main focus herein is to review the available literature on the role of phytate in pig and poultry nutrition, its degradation throughout the gut and opportunities to enhance the utilization of P as well as other minerals and nutrients which might be complexed by phytates.

Skin aging is driven by intrinsic and extrinsic factors impacting on skin functionality with progressive age. One factor of this multifaceted process is cellular senescence, as it has recently been identified to contribute to a declining tissue functionality in old age. In the skin, senescent cells have been found to markedly accumulate with age, and thus might impact directly on skin characteristics. Especially the switch from young, extracellular matrix-building fibroblasts to a senescence-associated secretory phenotype (SASP) could alter the microenvironment in the skin drastically and therefore promote skin aging. In order to study the influence of senescence in human skin, 3D organotypic cultures are a well-suited model system. However, only few "aged" skinequivalent (SE) models are available, requiring complex and long-term experimental setups. Here, we adapted a previously published full-thickness SE model by seeding increasing ratios of stress-induced premature senescent versus normal fibroblasts into the collagen matrix, terming these SE "senoskin". Immunohistochemistry stainings revealed a shift in the balance between proliferation (Ki67) and differentiation (Keratin 10 and Filaggrin) of keratinocytes within our senoskin equivalents, as well as partial impairment of skin barrier function and changed surface properties. Monitoring of cytokine levels of known SASP factors confirmedly showed an upregulation in 2D cultures of senescent cells and at the time of seeding into the skin equivalent. Surprisingly, we find a blunted response of cytokines in the senoskin equivalent over time during 3D differentiation.

The intestinal microbiota of piglets fed with a Control diet low in dietary fibre and modified wheat bran variants as an additional source of insoluble dietary fibre was characterised. In this context, variances in the microbiota of three different gut segments were assessed. Wheat bran was either included in its native form or modified by fermentation and extrusion before added at 150 g/kg to a basal diet for 48 piglets (12 animals per treatment). Total DNA was extracted from digesta samples from the jejunum, the end of the ileum and the colon ascendens. Samples were prepared accordingly for subsequent sequencing with the Illumina MiSeq. The obtained results revealed distinct location-specific differences in microbial composition. While Firmicutes were most predominant in all three gut segments, Bacteroidetes were additionally found in the colon at high abundance. The parameters of alpha and beta diversity analysis showed significant differences (p < 0.01) between the colon and the other two gut segments. Specialised bacterial groups like Prevotella and Ruminococcaceae were among the most predominant ones found in the colon, as they possess cellulolytic properties to degrade (at least partially) non-starch polysaccharides, while their abundance was negligible in the jejunum and the ileum. Conversely, the genera Lactobacillus, Bifidobacterium and Veillonella, for example, were among the most predominant groups in the jejunum and ileum, while in the colon they were hardly found. Although statistical taxonomical evaluation, following p-value correction, did not reveal pronounced differences in abundance related to bran modification, alpha and beta diversity analysis showed an influence regarding the various feeding strategies applied. Based on these findings, a more in-depth view on intestinal microbial composition within the gastrointestinal tract of young pigs fed with low- and high-fibre diets was generated.

Subacute ruminal acidosis (SARA) causes ruminal dysbiosis, thereby increasing the risk of systemic metabolic disorders in cattle. We recently showed that supplementation with phytogenic compounds (PHY) or autolyzed yeast (AY) counteracted negative effects of SARA by improving ruminal pH and microbiome. This study investigated the effects of an intermittent SARA challenge on the ruminal concentration of biogenic amines (BA) and lipopolysaccharides (LPS), as well as on the blood metabolome. We also evaluated effects of PHY and AY on the latter variables. Eight rumen-cannulated nonlactating Holstein cows were arranged in an incomplete 4 × 3 Latin square design with 4 experimental runs and 3 treatment groups. During each run, cows were switched from an all-forage diet (baseline) to an intermittent concentrate-challenge diet with a forage:concentrate ratio of 35:65 (dry matter basis) to induce SARA for 1 (SARA1) or 2 (SARA2) wk, separated by 1 wk of forage-only feeding. The 3 treatment groups were no additive as control, PHY, or AY. During baseline, SARA1 and SARA2 rumen fluid samples were collected for analysis of BA and LPS. Blood samples were taken during baseline and SARA1 for a targeted metabolomics approach. High-concentrate feeding caused a 9-fold increase in ruminal LPS during SARA1 and an 11-fold increase in SARA2 compared with the baseline. Elevated concentrations of ruminal BA were found during both SARA periods, with histamine showing the strongest increase during SARA1. Moreover, a decrease in phosphatidylcholines, lysophosphatidylcholines, sphingomyelines, and several AA in the blood during SARA1 were detected. Supplementation of PHY decreased concentrations of LPS (-43%), histamine (-66%), pyrrolidine (-38%), and spermine (-54%) in SARA1 and cadaverine in SARA2 (-50%). Moreover, cows that received PHY had higher concentrations of cholesterol (+26%), several AA, and phosphatidylcholines in SARA1 compared with control cows. For AY, decreases in ruminal ethanolamine (-21%), methylamine (-52%), histamine (-54%), spermidine (-44%), and spermine (-80%) in SARA1 were observed, whereas in the blood an increase in tryptophan was noticed. In conclusion, the SARA was associated with markedly increased concentrations of LPS and BA in the rumen fluid and undesirable shifts in the plasma metabolome. Supplementation of PHY and AY counteracted some of these changes and therefore may help in attenuating negative effects of high-concentrate feeding in dairy cattle.

ABSTRACT:In this study 120 piglets were allotted to 3 dietary treatments, negative control group, one group receiving a blend of essential oils (EO) derived from oregano, anise and citrus peels (40 mg/kg diet), and a positive control group treated with avilamycin as growth promoting feed additive (40 mg/kg diet). On day 22 of the experiment, 12 representative animals from each treatment group were sacrificed and tissue samples were collected for quantitative real time-PCR analysis and gut tissue morphology. EO and avilamycin decreased the gene expression of the transcriptional factor NFκB and the apoptotic marker TNFα significantly in the ileum and jejunum, respectively. The expression of the proliferation marker Cyclin D1 was also significantly decreased by both substances in the colon, mesenteric lymph nodes and spleen. The colonic crypt depth was reduced by avilamycin, and also numerically by the essential oils. These changes correlated with the up-regulation of the apoptosis factor Caspase 3. Histomorphometry revealed a smaller size of ileal Peyer's patches through the use of both feed additives, which correlated significantly with lower expression rates of NFκB. In conclusion, the results suggest that EO and avilamycin relieved weaning piglets from an immune defence stress in a similar way.

The effect of inulin and a multispecies probiotic formulation on performance and microbial parameters in a 28 days feeding trial with newly weaned piglets was assessed. Forty-eight piglets were allocated to a 2 × 2 factorial experiment involving two levels of inulin supplementation (0% or 0.4%) and two levels of probiotics (0 or 1 × 10(9) CFU/kg as fed, comprising enterococci, lactobacilli and bifidobacteria). In digesta samples obtained at slaughter (stomach, jejunum, ileum and colon), selected bacterial groups were enumerated and lactic acid, short chain fatty acids and ammonia concentrations analysed. The overall performance of piglets was unaffected by treatment. Inulin increased total aerobes in stomach and jejunum (p < 0.05), whereas enterococci declined in colon of the inulin group (p < 0.05). Furthermore decreasing colonic acetic acid (p < 0.01) and increasing lactic acid (p < 0.05) was observed for inulin. Probiotics increased total aerobes (p < 0.05) and enterococci (p < 0.01) in ileum and lactobacilli (p < 0.05), enterococci and gram-negative anaerobes (p < 0.01) in colon. Moreover, dry matter content in stomach and colon was lower and acetic acid in colon increased (p < 0.05). A decrease in ileal pH value was noted symbiotically for both additives. However, several parameters showed no synbiotic, but distinct individual effects of inulin and probiotics. Effects occurred along the entire gastrointestinal tract without restriction to the colon.

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