Location: Cell Wall Biology and Utilization Research
Project Number: 5090-21000-071-002-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Oct 1, 2015
End Date: Dec 31, 2019
Objective:
1) Determine the condensed tannin (CT) content and structural composition of various cranberry processing fractions; 2) Analyze cranberry juice concentrate (CJC) and cranberry pomace/meal (CPM) for their ability to inhibit protein degradation in in vitro experiments related to feeding dairy cows and ensiling forages; 3) investigate carbohydrate profile of CJC and CPM for supplementation of proposed total mixed rations. This project will provide information to determine if cranberry waste streams can be used as a product in dairy farm feeding systems, generating a defined value-added market with economic returns.
Approach:
Phase I (analytical studies).
1. Studies will be performed to purify condensed tannins (CTs) from whole cranberries (WC), cranberry juice concentrate (CJC), & cranberry pomace/meal (CPM). Such purification will be used as both a reference standard to determine CT content & to provide sufficient quantities of CT for in vitro studies.
2. The modified HCl-butanol method will be used to analyze CT content, and involves degradation/oxidation of the CT polymer into highly colored anthocyanidins. Concentration of CT present is proportional to the color generated.
3. CT activity in the binding of protein is dependent on the structural composition of the CTs in the plant material. Two analytical techniques (nuclear magnetic resonance [NMR] spectroscopy & thiolysis) will be used to determine structure & composition of cranberry CTs. Two-dimensional NMR techniques can detect CT in whole plant material & assess purity profiles & composition of purified CT samples. Thiolysis involves acid degradation of purified CT sample polymers into separate monomer subunits. The resulting mixture will be analyzed by high performance liquid chromatography (HPLC) to determine the percent composition of each monomer subunit contained in the original purified CT sample & the average length of polymer, & will provide a purity assessment of the CT sample.
4. Protein precipitation studies will be conducted with alfalfa protein extract to test the effectiveness of purified CT samples, CJC, & CPM to protect protein during ensiling and rumen digestion. These results may also indicate how the CT will perform in vivo in future studies.
5. Total analysis of carbohydrate type & content will be done on WC, CJC, & CPM. Valuation of this carbohydrate profile as an energy substitute for other total mixed ration amendments, i.e., corn, will be conducted.
Phase II (in vitro studies).
Preliminary data will be collected to determine the CT concentration required to protect protein, & to calculate the amounts of CJC & CPM which need to be added to feed stocks to increase nitrogen use efficiency (NUE).
1. In vitro rumen protein degradation studies will be conducted using both CJC & CPM in the inhibitor in vitro method. Degradation of protein will be measured by analyzing the protein degradation products (ammonium ion/amino acids, oligopeptides) released relative to a control sample.
2. Mini-silo experiments using macerated alfalfa & a dose-escalation of both CJC & CPM will be conducted to assess protein preservation during silage fermentation. The samples will be analyzed in the same manner as in the in vitro rumen protein degradation studies.
