In vitro protein fractionation methods for ruminant feeds

Area of Science:

• Animal Science
• Nutritional Biochemistry
• Ruminant Physiology

Background:

• Accurate estimation of protein fractions and degradation rates is crucial for optimizing ruminant nutrition.
• Traditional methods for protein analysis can be time-consuming and resource-intensive.
• The ANKOM gas production system offers a potential alternative for in vitro feed evaluation.

Purpose of the Study:

• To evaluate the ANKOM gas production system for estimating protein fractions and in vitro degradability of protein-rich feeds.
• To compare the efficacy of preserved versus fresh rumen fluid in protein fractionation using the ANKOM system.
• To validate the ANKOM system against established methods like the Cornell Net Carbohydrate and Protein System (CNCPS) and the uN_Ross assay.

Main Methods:

• Three in vitro methods were employed: ANKOM gas production, CNCPS, and uN_Ross assay.
• Protein fractions of lupin meal, vetch grain, Desmanthus hay, and soybean meal were quantified.
• Fresh rumen fluid was compared with rumen fluid preserved with dimethyl sulfoxide (DMSO) for gas production and uN_Ross assays.

Main Results:

• All methods consistently ranked feeds by available protein fractions: vetch grain, soybean meal, lupin meal, and Desmanthus hay.
• Fresh rumen fluid yielded higher available protein fractions than preserved fluid.
• Strong correlations were observed between protein fraction estimates from the ANKOM gas production method and the CNCPS method, particularly for fraction 'b'.

Conclusions:

• The ANKOM gas production system, utilizing either fresh or preserved rumen fluid, is a viable tool for protein fractionation in ruminant feeds.
• The system provides consistent feed rankings, supporting its use in nutritional management.
• Further research can optimize protocols for preserved rumen fluid to enhance its utility in routine analysis.