Carbon balances for in vitro digestion and fermentation of potential roughages for pregnant sows

Fermentability of select polyphenol-rich substrates in the canine faecal inoculum and their interaction with a canine-origin probiotic: an in vitro appraisal

BACKGROUND

This in vitro study aimed to compare the hindgut fermentability and digestibility of four different sources of polyphenols, namely orange (Citrus sinensis) peel (ORP), pomegranate (Punica granatum) peel (PMP), Indian blackberry (Syzygium cumini) pulp (IBP), and Jerusalem artichoke (Helianthus tuberosus) tuber (JAT), and their influence on the viability of a canine-origin probiotic, Lactobacillus johnsonii CPN23.

RESULTS

An in vitro gas production test carried out using the four substrates for a period of 72 h with dog faecal inoculum indicated that the total gas production, dry matter, and organic matter digestibility were significantly (P < 0.001) higher with JAT, whereas they were lowest for PMP. Short-chain fatty acids production was significantly higher (P < 0.001) with ORP and JAT, with the least values recorded for PMP. The ammonia-nitrogen production was significantly (P < 0.001) higher with JAT than with ORP, IBP, and PMP, and a lower (P < 0.001) pH was evident with ORP, JAT, and IBP than with PMP. Viability of L. johnsonii CPN23 was tested in the presence of the polyphenol-rich extract from each of the four sources at varying doses (50, 500, 1000, 2500, and 5000 μg mL^-1 ). PMP extract showed the highest inhibitory effect on the probiotic bacteria's growth in a dose- and time-dependent manner (P < 0.001). ORP and IBP extracts were stimulatory at the optimum dosage, whereas JAT reduced probiotic activity significantly at all doses tested.

CONCLUSION

Overall, the results indicate a higher hindgut fermentability of JAT, ORP, and IBP, suggesting their potential beneficial effects for gut health application. An interaction study between polyphenol extract and L. johnsonii CPN23 showed a stimulatory effect of polyphenolic extracts from ORP and IBP on probiotic growth at optimal dosage. Consistent with the fermentation study findings, PMP extract reduced the growth of L. johnsonii CPN23 irrespective of the doses tested. © 2021 Society of Chemical Industry.

Incubation of selected fermentable fibres with feline faecal inoculum: correlations between in vitro fermentation characteristics and end products

This study aimed to evaluate correlations between fermentation characteristics and end products of selected fermentable fibres (three types of fructans, citrus pectin, guar gum), incubated with faecal inocula from donor cats fed two diets, differing in fibre and protein sources and concentrations. Cumulative gas production was measured over 72 h, fermentation end products were analysed at 4, 8, 12, 24, 48 and 72 h post-incubation, and quantification of lactobacilli, bifidobacteria and bacteroides in fermentation liquids were performed at 4 and 48 h of incubation. Partial Pearson correlations, corrected for inoculum, were calculated to assess the interdependency of the fermentation characteristics of the soluble fibre substrates. Butyric and valeric acid concentrations increased with higher fermentation rates, whereas acetic acid declined. Concentrations of butyric acid (highest in fructans) and propionic acid were inversely correlated with protein fermentation end products at several time points, whereas concentrations of acetic acid (highest in citrus pectin) were positively correlated with these products at most time points. Remarkably, a lack of clear relationship between the counts of bacterial groups and their typically associated products after 4 h of incubation was observed. Data from this experiment suggest that differences in fibre fermentation rate in feline faecal inocula coincide with typical changes in the profile of bacterial fermentation products. The observed higher concentrations of propionic and butyric acid as a result of fibre fermentation could possibly have beneficial effects on intestinal health, and may be confounded with a concurrent decrease in the production of putrefactive compounds. In conclusion, supplementing guar gum or fructans to a feline diet might be more advantageous compared with citrus pectin. However, in vivo research is warranted to confirm these conclusions in domestic cats.

State of the art in feedstuff analysis: a technique-oriented perspective

The need for global feed supply traceability, the high-throughput testing demands of feed industry, and regulatory enforcement drive the need for feed analysis and make extremely complex the issue of the control and evaluation of feed quality, safety, and functional properties, all of which contribute to the very high number of analyses that must be performed. Feed analysis, with respect to animal nutritional requirements, health, reproduction, and production, should be multianalytically approached. In addition to standard methods of chemical analysis, new methods for evaluation of feed composition and functional properties, authenticity, and safety have been developed. Requirements for new analytical methods emphasize performance, sensitivity, reliability, speed, simplified use, low cost for high volume, and routine assays. This review provides an overview of the most used and promising methods for feed analysis. The review is intentionally focused on the following techniques: classical chemical analysis; in situ and in vitro methods; analytical techniques coupled with chemometric tools (NIR and sensors); and cell-based bioassays. This review describes both the potential and limitations of each technique and discusses the challenges that need to be overcome to obtain validated and standardized methods of analysis for a complete and global feed evaluation and characterization.

Manipulating digestion with foods designed to change the physical characteristics of digesta

We explore how foods can be designed to modulate digestion and to promote health by changing the physical properties of digesta. The physical characteristics of digesta are discussed along with their impact on the physiology of digestion with special reference to sites where these characteristics are likely to influence digestive efficiency. Evidence is reviewed regarding the effects of supplementation with viscoactive agents on the flow and mixing of digesta in particular segments of the human gut that, by changing the rheology and liquid permeability of digesta in that segment, influence specific aspects of digestion and absorption.