Surfactants are extremely important agents to clean and sanitize various environments. Their biocidal activity is a key factor determined by the interactions between amphiphile structure and the target microbial cells. The object of this study was to analyze the interactions between four structural variants of N-alkyltropinium bromide surfactants with the Gram negative Escherichia coli and the Gram positive Listeria innocua bacteria. Microbiological and conductometric methods with a previously described FTIR bioassay were used to assess the metabolomic damage exerted by these compounds. All surfactants tested showed more biocidal activity in L. innocua than in E. coli. N-tetradecyltropinium bromide was the most effective compound against both species, while all the other variants had a reduced efficacy as biocides, mainly against E. coli cells. In general, the most prominent metabolomic response was observed for the constituents of the cell envelope in the fatty acids (W1) and amides (W2) regions and at the wavenumbers referred to peptidoglycan (W2 and W3 regions). This response was particularly strong and negative in L. innocua, when cells were challenged by N-tetradecyltropinium bromide, and by the variant with a smaller head and a 12C tail (N-dodecylquinuclidinium bromide). Tail length was critical for microbial inhibition especially when acting against E. coli, maybe due the complex nature of Gram negative cell envelope. Statistical analysis allowed us to correlate the induced mortality with the metabolomic cell response, highlighting two different modes of action. In general, gaining insights in the interactions between fine structural properties of surfactants and the microbial diversity can allow tailoring these compounds for the various operative conditions.

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The faba bean is a legume primarily used in animal feeding as grain and, to a lesser degree, as fodder. As noted, grain, being a good source of amylacea (starch) (45–50% DM) and protein (23–30 CP%DM) of discrete biological value (Verite and Peyraud, 1988), acts as an alternative to soybean which is particularly suitable for organic breeding. Despite this, low productive yields and the presence of thermostable antinutritional factors have reduced the diffusion of this legume especially in feeding non-ruminant species. The objective of the current work was that of investigating the effect of the genotype and conditions (time and place of sowing) on the amount in polyphenols, vicine, convicine and phytates of five varieties of faba bean (Vicia faba var. minor) that have recorded the best protein yields under Umbrian pedoclimatic conditions (Monotti et al., 2004; Mannino, 2003)

Polyunsaturated fatty acids affect bacterial and protozoal population, inducing important modifications in rumen metabolism. The aim of this study was to investigate the effect of linseed extrusion on in situ ruminal degradability and microbial number and distribution. Six ruminally fistulated sheep were divided in 3 groups and fed one of the following diets according to a replicated Latin square design: (a) control, based on mixed hay and maize grains; (b) as in (a) plus 130 g of grounded raw linseed; (c) as in (b) except that the linseed was extruded. Extrusion decreased linseed dry matter and fat degradabilities. There was a marked reduction of total protozoal population in sheep fed supplemented diets. No effects were observed between groups on bacterial concentration, hay dry matter and NDF in situ degradabilities

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