Effects of tannins and drying methods on in vitro dry matter and crude protein degradability and digestibility in rapeseed meal
Year: 2026
Type: article
Abstract: The extensive ruminal degradability of rapeseed meal limits its efficiency as a protein source in ruminant diets by reducing the proportion of dietary protein available for post-ruminal absorption. This study, conducted entirely in vitro, investigated the interactive effects of two tannin types: chestnut water extract (CWE) and quebracho extract (QUE), two tannin inclusion levels (50 or 100 g/kg), and three drying methods (freeze-drying, oven drying at 50 °C or 80 °C) on the in vitro dry matter and crude protein degradability and digestibility of rapeseed meal. In vitro assessments were conducted using rumen fluid from cannulated rams and a three-step enzymatic procedure. A three-way linear model including tannin type, concentration, drying method and their interactions was used. In vitro crude protein degradability decreased by 128 and 243 g/kg dry matter when 50 and 100 g chestnut/kg were included and dried at 50 °C, respectively. By-pass protein content increased by 105 and 219 g/kg dry matter with included 50 g CWE/kg and 100 g QUE/kg dried at 50 °C, respectively. Notably, the combination of 100 g CWE/kg and 80 °C drying significantly reduced in vitro crude protein digestibility by 50 g/kg dry matter. At 80 °C drying, in vitro dry matter degradability reduced the most, by 237 and 366 g/kg dry matter at added 100 g QUE and CWE/kg, respectively. Overall, the application of tannins with drying at 50 °C or 80 °C can improve the amount of by-pass protein in rapeseed meal. These findings indicate a potential for novel tannin-processing strategies of rapeseed meal in ruminant nutrition.
Authors: Nejc Valcl, Andrej Lavrenčič
Institution: University of Ljubljana
Language: English
Subfield: Agronomy and Crop Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $1,590
OpenAlex ID: W7204465894