Narasin.
21 C.F.R. § 558.363
in effectEffective: 2024-07-01(a) Specifications. Type A medicated articles containing 36, 45, 54, 72, or 90 grams narasin per pound.
(b) Sponsor. See No. 058198 in § 510.600(c) of this chapter.
(c) Tolerances. See § 556.428 of this chapter.
(d) Special considerations. An expiration date of 2 months (8 weeks) is required for narasin Type C medicated swine feeds.
(e) Conditions of use. It is used as follows:
(1) Chickens—
(2) Swine—
(3) Narasin single-ingredient Type A medicated articles may also be used in combination with:
(i) Avilamycin as in § 558.68.
(ii) [Reserved]
Source: eCFRURL: https://www.ecfr.gov/api/versioner/v1/full/2024-07-01/title-21.xmlFetched: 7/26/2026