In vitro evaluation of the fermentation characteristics of the carbohydrate fractions of hulless barley and other cereals in the gastrointestinal tract of pigs

An in vitro model was used to study the fermentation characteristics of carbohydrate fractions of hulless barley (hB), in comparison to hulled barley (HB), hulled oat and oat groats (OG) in the pig intestine. For this purpose, 6 hulless barley cultivars (hB), varying in β-glucan content (36–99 g/kg DM), were compared to 3 HB cultivars, 2 oat groat samples (OG), 3 oat varieties and a reference sample of wheat. The residue of a pepsin–pancreatin hydrolysis was incubated in a buffered mineral solution inoculated with pig faeces. Gas production, proportional to the amount of fermented carbohydrates, was measured for 48 h and kinetics modelled. The fermented solution was subsequently analyzed for microbial production of short-chain fatty acids (SCFA) and ammonia. In vitro dry matter degradability varied according to ingredient (P<0.001). Higher values were observed for OG, ranging from 0.88 to 0.99 as compared to oat, hB and HB, for which degradability ranged from 0.63 to 0.73, 0.68 to 0.80 and 0.69 to 0.71, respectively. A “cereal type” effect (P<0.05) was observed on fermentation kinetics parameters. Total gas production was higher (P<0.05) with hB (224 ml/g DM incubated) than with HB and oat (188 and 55 ml/g DM incubated, respectively). No difference was observed between hB cultivars (P>0.05) for total gas production but differences (P<0.001) were found for lag time and the fractional rate of degradation. Hulless barley cultivar CDC Fibar (waxy starch) and CDC McGwire (normal starch) started to ferment sooner (lag time of 0.7 and 0.9 h, respectively) than SH99250 (high amylose starch; 1.7 h). The fractional rate of degradation was similar in both hB and OG (0.15/h on average), which was higher than that of HB (0.12/h). The production of SCFA was also higher (P<0.05) with hB (6.1 mmol/g DM incubated, on average) than with HB and oat (4.9 and 2.9 mmol/g DM incubated, respectively). Similar trends were found for SCFA production expressed per g fermented carbohydrates, with higher butyrate and lower acetate ratio. In contrast, oat fermentation generated higher (P<0.05) ammonia concentration (1.4 mmol/g DM incubated, on average) than hB (1.0 mmol/g DM incubated). In summary, hulless barleys, irrespective of cultivar type had higher in vitro fermentability and produced more SCFA and less ammonia than hulled barley and oat. Thus, hulless barleys have a better potential to be used in pig nutrition to manipulate the fermentation activity in the intestine of pigs.     

6,7,4′-trihydroxyisoflavan: A potent and selective inhibitor of 5-lipoxygenase in human and porcine peripheral blood leukocytes

The effect of 6,74′-trihydroxyisoflavan on human platelet 12-lipoxygenase and human and porcine PMNL 5-lipoxygenase activities has been studied. 6,7,4′-Trihydroxyisoflavan was found to inhibit 5-lipoxygenase more strongly than 12-lipoxygenase; its concentration for 50% inhibition (IC₅₀) was 1.6 μm for human and porcine 5-lipoxygenase adn 22 μM for human platelet 12-lipoxygenase. Inhibition of microsomal cyclooxygenase from ram seminal vesicles is exhibited at much higher concentrations of 6,7,4′-trihydroxyisoflavan (IC₅₀ = 200 μM).     

Genotoxic effects of sodium arsenite on human cells.

The effects of sodium arsenite (SA) were studied either alone or in combination with X-rays in peripheral blood lymphocytes, and with short-wave ultraviolet (UV) radiation in primary human fibroblast culture systems. It was found that SA (i) inhibited the cell cycle progression of phytohaemagglutinin (PHA)-responsive lymphocytes, (ii) induced chromatid-type aberrations and sister-chromatid exchanges (SCEs) as a function of concentration and (iii) potentiated the X-ray- and UV-induced chromosomal damage. Our results suggest that SA interferes with the DNA repair process, presumably by inhibiting the ligase activity. This accounted for an increase in the DNA replication-dependent processes, chromatid aberrations and SCEs and synergistic enhancement of the X-ray- and UV-induced chromosomal damage. This ability of arsenite may be responsible for its comutagenic properties with different types of mutagens and hence its carcinogenicity.