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Code · CFR · Title 21 — Food and Drugs · Part 558 — New Animal Drugs for Use in Animal Feeds · § 558.363

§ 558.363. Narasin.

977 words·~4 min read·/us/cfr/t21/s§ 558.363·

A research copy — for the controlling text, always check the official state or federal source. Not legal advice.

(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— Narasin grams/ton Combination in grams/ton Indications for use Limitations Sponsor
(i)54 to 90Broiler chickens: For prevention of coccidiosis caused by Eimeria necatrix, E. tenella, E. acervulina, E. brunetti, E. mivati, and E. maximaFor broiler chickens only. Feed continuously as sole ration. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal058198
(ii)54 to 72Bacitracin (as feed grade bacitracin methylenedisalicylate), 10 to 50Broiler chickens: For the prevention of coccidiosis caused by Eimeria necatrix, E. tenella, E. acervulina, E. brunetti, E. mivati, and E. maxima, and for increased rate of weight gain and improved feed efficiencyFeed as the sole ration. The narasin concentration should be adjusted to meet the severity of the coccidial challenge, which varies with environmental and management conditions. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Bacitracin methylenedisalicylate as provided by No. 066104 in § 510.600(c) of this chapter066104
(iii)54 to 90Bacitracin (as feed grade bacitracin methylenedisalicylate), 4 to 50Broiler chickens: For increased rate of weight gain and improved feed efficiency, and for the prevention of coccidiosis caused by Eimeria necatrix, E. tenella, E. acervulina, E. brunetti, E. mivati, and E. maximaFeed as the sole ration throughout the feeding period. The narasin concentration should be adjusted to meet the severity of the coccidial challenge, which varies with environmental and management conditions. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Bacitracin methylenedisalicylate as provided by No. 069254 in § 510.600(c) of this chapter069254
(iv)54 to 90Bacitracin (as feed grade bacitracin methylenedisalicylate), 50Broiler chickens: For the prevention of mortality caused by necrotic enteritis associated with Clostridium perfringens, and for the prevention of coccidiosis caused by Eimeria necatrix, E. tenella, E. acervulina, E. brunetti, E. mivati, and E. maximaFeed as the sole ration for 28 to 35 days, starting from the time chicks are placed for brooding. The narasin concentration should be adjusted to meet the severity of the coccidial challenge, which varies with environmental and management conditions. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Bacitracin methylenedisalicylate as provided by No. 069254 in § 510.600(c) of this chapter069254
(v)54 to 72Bacitracin (as feed grade bacitracin zinc), 4 to 50Broiler chickens: For the prevention of coccidiosis caused by Eimeria necatrix, E. tenella, E. acervulina, E. brunetti, E. mivati, and E. maxima, and for increased rate of weight gain and improved feed efficiencyFeed as the sole ration. The narasin concentration should be adjusted to meet the severity of the coccidial challenge, which varies with environmental and management conditions. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Bacitracin zinc as provided by No. 054771 in § 510.600(c) of this chapter066104
(vi)54 to 72Bambermycins, 1 to 2Broiler chickens: For prevention of coccidiosis caused by Eimeria necatrix, E. tenella, E. acervulina, E. brunetti, E. mivati, and E. maxima, and for increased rate of weight gain and improved feed efficiencyFor broiler chickens only. Feed continuously as sole ration. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Bambermycins as provided by No. 016592 in § 510.600(c) of this chapter016592
(2)Swine— Narasin grams/ton Combination in grams/ton Indications for use Limitations Sponsor
(i)13.6 to 27.2Growing-finishing swine: For increased rate of weight gain when fed for at least 4 weeksFeed continuously for at least 4 weeks to swine during the growing-finishing period as the sole ration. No increased benefit in rate of weight gain has been shown when narasin concentrations in the diet are greater than 13.6 g/ton. Effectiveness has not been demonstrated when fed for durations less than 4 weeks. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Not approved for use in breeding animals because safety and effectiveness have not been evaluated in these animals. Swine being fed with narasin should not have access to feeds containing pleuromutilins (e.g., tiamulin) as adverse reactions may occur. If signs of toxicity occur, discontinue use058198
(ii)18.1 to 27.2Growing-finishing swine: For increased rate of weight gain and improved feed efficiency when fed for at least 4 weeksFeed continuously for at least 4 weeks to swine during the growing-finishing period as the sole ration. No increased benefit in rate of weight gain has been shown when narasin concentrations in the diet are greater than 13.6 g/ton. Effectiveness has not been demonstrated when fed for durations less than 4 weeks. Do not allow adult turkeys, horses, or other equines access to narasin formulations. Ingestion of narasin by these species has been fatal. Not approved for use in breeding animals because safety and effectiveness have not been evaluated in these animals. Swine being fed with narasin should not have access to feeds containing pleuromutilins (e.g., tiamulin) as adverse reactions may occur. If signs of toxicity occur, discontinue use058198
(3)Narasin single-ingredient Type A medicated articles may also be used in combination with:
(i)Avilamycin as in § 558.68.
(ii)[Reserved] [83 FR 64741, Dec. 18, 2018, as amended at 86 FR 14825, Mar. 19, 2021; 91 FR 20345, Apr. 16, 2026]
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§ 558.363
Narasin.
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