Reducing agent can be omitted in the incubation medium of the batch in vitro fermentation model of the pig intestines

Autor: C. Poelaert, G. Nollevaux, C. Boudry, B. Taminiau, C. Nezer, G. Daube, Y.-J. Schneider, D. Portetelle, A. Théwis, J. Bindelle
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Animal, Vol 12, Iss 6, Pp 1154-1164 (2018)
Druh dokumentu: article
ISSN: 1751-7311
17517311
DOI: 10.1017/S1751731117002749
Popis: Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by a bacterial inoculum diluted in a mineral buffer solution. Generally, a reducing agent such as Na2S or cysteine-HCl generates the required anaerobic environment by releasing metabolites similar to those produced when protein is fermented, possibly inducing a dysbiosis. An experiment was conducted to study the impact of two reducing agents on results yielded by such in vitro fermentation models. Protein (soybean proteins, casein) and carbohydrate (potato starch, cellulose) ingredients were fermented in vitro by bacteria isolated from fresh feces obtained from three sows in three carbonate-based incubation media differing in reducing agent: (i) Na2S, (ii) cysteine-HCl and (iii) control with a mere saturation with CO2 and devoid of reducing agent. The gas production during fermentation was recorded over 72 h. Short-chain fatty acids (SCFA) production after 24 and 72 h and microbial composition of the fermentation broth after 24 h were compared between ingredients and between reducing agents. The fermentation residues after 24 h were also evaluated in terms of cytotoxicity using Caco-2 cell monolayers. Results showed that the effect of the ingredient induced higher differences than the reducing agent. Among the latter, cysteine-HCl induced the strongest differences compared with the control, whereas Na2S was similar to the control for most parameters. For all ingredients, final gas produced per g of substrate was similar (P>0.10) for the three reducing agents whereas the maximum rate of gas production (Rmax) was reduced (P0.10) after 24 h of fermentation with Na2S and in the control without reducing agent. Molar ratios of branched chain-fatty acids were higher (P
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