L-isoleucine in pet food

As an essential amino acid for pet growth, L-isoleucine is regulated by relevant regulations and standards in pet food, as detailed below:

Additive Approval Standards

The European Commission has issued Regulation (EU) 2025/143, approving L-isoleucine produced by Corynebacterium glutamicum CGMCC 20437 as a feed additive for all animals, classified as a "nutritional additive" under the functional group of "amino acids, their salts, and analogues". Additionally, Regulation (EU) 2023/2583 approved L-isoleucine produced by Corynebacterium glutamicum KCCM80185 for use as a feed additive in all animal feeds. Japan's Ministry of Agriculture, Forestry and Fisheries also allows L-isoleucine as a feed additive in accordance with relevant announcements and regulations.

Content Standards

According to FEDIAF (European Pet Food Industry Federation) standards, the minimum recommended isoleucine content in dry-based dog food per 100g is:

0.53g for adulthood

0.65g for puppies under 14 weeks and breeding periods

0.50g for puppies over 14 weeks

For cat food, the minimum recommended isoleucine content per 100g dry basis is:

0.57g for adulthood

0.54g for kittenhood and breeding periods

The National Institutes of Health (NIH) standards stipulate that isoleucine content in dog food must be ≥1.0%, and in cat food ≥1.4%.

AAFCO (Association of American Feed Control Officials) standards show the maximum isoleucine content in dog food is:

0.45g for the growth/fertility period

0.37g for adulthood

For cat food, the maximum isoleucine content is 0.52g.