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In vitro fermentation characteristics of diets with different forage/concentrate ratios: comparison of rumen and faecal inocula
Author(s) -
Zicarelli Fabio,
Calabrò Serena,
Cutrignelli Monica I,
Infascelli Federico,
Tudisco Raffaella,
Bovera Fulvia,
Piccolo Vincenzo
Publication year - 2011
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.4302
Subject(s) - rumen , fermentation , dry matter , forage , biology , zoology , organic matter , feces , food science , biomass (ecology) , chemistry , agronomy , microbiology and biotechnology , ecology
BACKGROUND: The aim of this trial was to evaluate the replacement of rumen fluid with faeces as inoculum in studying the in vitro fermentation characteristics of diets for ruminants using the in vitro gas production technique. Six iso‐protein diets with different forage/concentrate ratios were incubated with rumen fluid (RI) or faeces (FI) collected from sheep. RESULTS: Most of the fermentation parameters were influenced by diet and inoculum ( P < 0.01). With both inocula, organic matter degradability (dOM), cumulative gas production (OMCV) and maximum fermentation rate ( R max ) increased as the amount of concentrate in the diet increased. R max was lower with FI vs RI ( P < 0.01); dOM was higher with FI vs RI and the diet × inoculum interaction was significant. As expected, with both inocula, R max increased as the neutral detergent fibre content of the diet decreased. Significant correlations were obtained using both inocula between OMCV/dOM and gas/volatile fatty acid (VFA), while the correlation VFA/dOM was significant only with FI. The microbial biomass yield calculated by stoichiometric analysis for all diets was higher with FI vs RI. With FI the organic matter used for microbial growth showed an overall decreasing trend as the amount of concentrate in the diet increased. CONCLUSION: The results indicate that both faeces and rumen fluid from sheep have the potential to be used as inoculum for the in vitro gas production technique. Copyright © 2011 Society of Chemical Industry