In vitro rumen fermentation characteristics of substrate mixtures with soybean meal partially replaced by microbially fermented yellow wine lees

Abstract

This study was conducted to evaluate the effects of replacing soybean meal (SBM) with unfermented and microbially fermented yellow wine lees (YWL) mix on the in vitro rumen fermentation characteristics of substrate mixtures. Both types consisting of YWL at 400 g/kg were included in the mixtures at different ratios (1:0, 1:1, 1:2, 1:5 and 0:1, w/w) to replace SBM. Microbial fermentation of YWL did not have a negative impact on gas value (p> .05), increased microbial protein (MCP, p < .01) and in vitro crude protein (CP) digestibility (p < .01), and improved the efficiency of nitrogen utilisation (p < .01). The ratio of YWL replacing SBM had linear and quadratic effects on gas production (GP, p < .01), the rate of GP (p < .01), MCP (p < .01), total volatile fatty acids (VFAs, p < .01), in vitro CP digestibility and efficiency of nitrogen utilisation (p < .01), with the optimal ratio at 1:1. The in vitro digestibilities of dry matter and organic were slightly (p < .01) reduced with the increasing ratio of YWL. Besides, positive associative effects were observed on GP parameters, VFA and MCP at some replacement ratios. Considering the in vitro rumen characteristics and their associative effects, the optimal ratio at which to replace SBM with microbially fermented YWL was indicated to be 1:1. HIGHLIGHTS The in vitro rumen fermentation characteristics performed better with microbially fermented than unfermented yellow wine lees (YWL) replacing soybean meal (SBM). The positive associative effects were observed on gas production parameters, volatile fatty acid and microbial protein at replacing ratio of 1:1. The optimal ratio at which to replace SBM with microbially fermented YWL was 1:1.

Models Based on the Mitscherlich Equation for Describing Typical and Atypical Gas Production Profiles Obtained from In Vitro Digestibility Studies Using Equine Faecal Inoculum

“…These model-derived parameters have been used in conjunction with information regarding substrate degradability and digesta passage rate to calculate extent of substrate degradation in the rumen [3][4][5][6]34]. This method has been successfully applied to typical monophasic sigmoidal and diminishing returns gas profiles to evaluate substrates based upon the extent of their degradability [3,5,6,[8][9][10][11][12][13][14]34].…”

“…where w 1 and w 2 are the relative weights assigned to the respective phases. If the profile resolves into a diminishing returns and a linear (with abrupt cut-off) component as in Equation 4, then Equations (5) and (8) respectively can be applied to the two phases and the overall extent calculated again using Equation (9). As an arbitrary rule of thumb, the asymptotic gas production values for the two phases (abrupt cut-off value if a phase is linear), viz.…”

“…This technique is based upon the assumption that the gas produced from incubating a feedstuff with a microbial inoculum is the consequence of the anaerobic fermentation of that feedstuff [3]. In ruminant nutrition, gas production profiles generated have been used in conjunction with the retention time of digesta (derived from the rate of passage) to determine extent of degradation in the rumen [3][4][5][6][7][8][9]. In equine nutrition, the technique has been proposed as an in vitro surrogate for determining the digestibility and nutritive value of feedstuffs using in vivo methods [10][11][12][13][14].…”

Effect of Yellow Wine Lees Supplementation on Milk Antioxidant Capacity and Hematological Parameters in Lactating Cows under Heat Stress

“…Details, including cost of the experimental rations, are described in Supplementary Table S1. The percentage for YWL feed inclusion was based on the former in vitro study [20] and the DMI and milk yield of FM was similar to the control diet, reported in the previous production study [21]. All of the diets were isonitrogenous and isocaloric, with a forage-to-concentrate ratio of 60:40 (DM basis), and met the requirement of net energy for lactation (NE L ) producing 29 kg/day milk in dairy cows (Ministry of Agriculture of China, (Beijing, China), 2004) [21].…”

“…We previously found that the antioxidant activity of the YWL can be improved when fermented with Candida utilis and Bacillus subtilis [ 19 ]. In our preliminary in vitro study, when the ratio of soybean meal (SBM) to unfermented (UM) or fermented YWL mix (FM) in the simulated ration was at 1:1 (DM basis), the gas production parameters and volatile fatty acids were optimized and functioned similarly to the rations with SBM as the main protein resource [ 20 ]. Moreover, we observed that total mixed rations (TMR) with partial replacement of SBM with UM/FM did not affect feed efficiency and milk compositions, indicating YWL as a potential protein source in dairy rations [ 21 ].…”