What Is Rumen-Protected DL-Methionine 50% (RPM) - Palm-Fat Coated Granules? Applications, Dosage, Alternatives & Specifications
Last updated: 2026-11-14 · CAS 59-51-8 · Feed Grade
- Quick facts
- Name
- Rumen-Protected DL-Methionine 50% (RPM) - Palm-Fat Coated Granules
- CAS number
- 59-51-8
- Grade
- Feed Grade
- Certifications
- ISO 9001 · ISO 22000 · HACCP · FAMI-QS · Kosher · Halal · GMP · SGS
- Application areas
- 3
- Documentation
- COA · TDS · SDS
Overview
Rumen-Protected Methionine (RPM) is a feed additive produced by physically protecting DL-methionine or L-methionine through a palm-oil (vegetable fat) coating to maintain stability in the rumen of ruminants (rumen degradation rate below 15%) and to release and be absorbed in the abomasum and small intestine. Methionine is the first limiting amino acid for ruminants, especially dairy cows. However, ordinary methionine added directly to feed is rapidly degraded by rumen microorganisms (degradation rate exceeding 80%) and cannot reach the small intestine to exert its nutritional effects. Rumen-protected technology is the key to solving this bottleneck. Rumen-protected methionine is converted to methionine in the small intestine after passing through the rumen, increasing the amount of methionine entering the small intestine, improving small intestinal amino acid balance, and increasing serum essential amino acid concentrations, nitrogen utilization efficiency, and production performance in dairy cows. Rumen-protected methionine is listed in China's "Catalog of Feed Additives." The product is manufactured and tested under the manufacturer enterprise standard Q/371626FLK 024-2026.
Rumen-protected methionine can be divided into the following main varieties by coating material, production process, and content specification.
Applications
Dairy Cattle
The largest market for rumen-protected methionine (~86.3% of demand); RPM balances metabolizable methionine to support milk protein and milk fat, especially in low-protein diets.
Beef Cattle
Improves feed efficiency, rumen fermentation and nitrogen balance, and acts as a methyl donor that supports liver health and antioxidant capacity during finishing.
Sheep & Ruminants
Supports average daily gain in lambs and helps young ruminants resist weaning stress through higher total antioxidant capacity and balanced amino acid supply.
Specification
| Item | Specification | Test Method / Note |
|---|---|---|
| Appearance | White to off-white granules, good fluidity | Visual (COA batch 20260806C: Conform) |
| DL-Methionine Content | ≥50% (batch result 50.05%) | HPLC |
| Carrier / Coating | Palm oil (vegetable fat); fat <50% | — |
| Rumen Bypass Rate | ≥85% (batch: Conform) | Nylon-bag / in vitro simulation |
| Intestinal Release Rate | ≥90% (batch: Conform) | Intestinal fluid digestion |
| Loss on Drying | ≤5% (batch result 1.10%) | Drying, 105 °C |
| Particle Size | 100% through 10 mesh (2.00 mm) | Sieving |
| Molecular Formula / Weight | C5H11O2NS · MW 149.21 | TDS |
| Test Method Standard | Q/371626FLK 024-2026 | Manufacturer enterprise standard |
| Packaging | 25 kg / bag | — |
| Shelf Life | 12 months, sealed, cool & dry | TDS |
Packaging & Storage
- Packing: 25 kg net kraft/PP woven bags with PE liner; fibre drum available on request.
- Sample: 100-500g free sample available.
- Storage: Keep in tightly closed packaging, cool, dry, well-ventilated. Protect from light and moisture.
- Shelf Life: 12 months from production date.
Quality & Certifications
Every batch tested by in-house QC lab. COA, TDS, SDS provided with each shipment.
Regulatory & Compliance
EU
Complies with EU regulations and FAMI-QS standards.
USA
Meets FDA and AAFCO requirements.
China
Registered under Chinese MOA regulations.
International
Kosher, Halal, ISO certified. FTA forms available.
Safety & Handling
- Hazard Class: Generally non-hazardous. Refer to SDS for details.
- Storage: Room temperature, dry, sealed. Avoid strong oxidizers.
- Transport: Non-dangerous goods. Standard sea/air freight.
- SDS: Available on request at sales@xadditive.cn.
Frequently asked questions
What is rumen-protected methionine (RPM)?
Rumen-protected methionine is a feed additive in which DL-methionine granules are coated with a solid palm-fat layer so the amino acid survives the rumen and is released and absorbed in the abomasum and small intestine. It contains ≥50% DL-methionine and has CAS number 59-51-8.
How does rumen-protected methionine work?
The palm-fat coating stays solid and largely undegraded in the rumen, protecting the methionine from rumen microbes. In the abomasum and small intestine the fat coating breaks down, releasing the methionine so it can be absorbed into the bloodstream and used for milk protein synthesis and growth.
What is the rumen bypass rate of coated methionine?
The ZEAL palm-fat coated RPM has a rumen bypass rate of ≥85% and an intestinal release (digestion and absorption) rate of ≥90%, measured by nylon-bag/in-vitro and intestinal-fluid methods.
How much rumen-protected methionine should I feed dairy cows?
A typical inclusion for lactating dairy cows is 15–30 g per head per day; commercial RPM references are often 8–12 g/head/day, or 1–3 kg per tonne of concentrate supplement. Final levels should be set to the metabolizable methionine target of the ration.
What is the difference between rumen-protected methionine and ordinary methionine?
Ordinary methionine added directly to ruminant feed is more than 80% degraded by rumen microbes and little reaches the small intestine. Coated methionine bypasses the rumen (≥85%) and is absorbed at ≥90%, giving much higher bioavailability.
What is the difference between RPM and methionine hydroxy analogue (MHA)?
RPM directly supplies DL-methionine that is absorbed in the small intestine. MHA (2-hydroxy-4-methylthiobutanoic acid) is an analogue that must first be converted into methionine in the body, so its effective bioavailability is lower and formulation-dependent.
Does rumen-protected methionine improve milk protein and milk fat?
Yes. Field and literature responses report higher milk yield, milk protein content and milk fat percentage, together with better nitrogen utilization and lower nitrogen excretion when RPM is used to balance low-protein dairy diets.
Why is methionine described as the first limiting amino acid for dairy cows?
Methionine is the essential amino acid most deficient relative to the cow's requirement for milk protein synthesis. When it is limiting, adding other protein cannot raise milk protein until metabolizable methionine is supplied, which RPM does efficiently.
What is the shelf life and packaging of coated methionine?
It is packed in 25 kg bags (fibre drum/PP woven with PE liner) and has a 12-month shelf life when stored sealed in a cool, dry, well-ventilated place away from light and moisture.
What is the MOQ and can I get a free sample?
The trial MOQ is 1 kg and 25 kg for regular orders. Free samples (typically 100–500 g) are available; contact sales@xadditive.cn and a quotation is usually provided within 30 minutes.
Request a quote & COA
Ask for the current specification sheet, a COA sample and a bulk quotation — reply within 30 minutes on working days.