Nitrogen and in vitro fermentation of nitrogenous substrates in caecal contents of the pig
2002
Marounek, M. (Akademie Ved, Prague (Czech Republic). Ustav Zivocisne Fyziologie a Genetiky) | Adamec, T. | Skrivanova, V. | Latsik, N.I.
Caecal concentrations of four 28-week-old pigs were analysed and used as inocula of cultures supplied with plant proteins, mucin, RNA and glucose. Pigs were fed ad libitum a 14.1 % crude protein diet containing barley, wheat, wheat bran, extracted soybean meal and a feed supplement. The caecal digesta contained dry matter, total N, protein, trichloroacetic acid (TCA)-soluble N and NH3-N at 120, 3.1, 14.9, 0.64 and 0.27 mg/g (on average), respectively. One g of the caecal content contained 70 micromol of glycine equivalents of amino acids in TCA-soluble fraction. Fermentation of mucin yielded motre volatile fatty acids (VFA) than fermentation of other nitrogenous substrates. Zein was the least fermentable substrate tested. Acetate was the principal fermentation end-product, followed by propionate and butyrate. Fermentation pattern differed in cultures grown on glucose and proteins: propionate molar proportions were higher and those of branched-chain VFA lower in former cultures than in cultures supplied with gluten, gliadin, and zein. Low proportions of branched-chain VFA were also in VFA produced from mucin and RNA. Caecal microorganisms convert nitrogenous substrates into valuable products (VFA) utilizable by the host.
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