Section 52. Each commercial feed shall be registered before being distributed in the commonwealth; provided, however, that customer-formula feeds are exempt from registration. The application for registration shall be submitted on forms furnished by the commissioner or his deputy and if the commissioner so requests, shall also be accompanied by a label or other printed matter describing the product. Upon approval by the commissioner or his deputy a copy of the registration shall be furnished to the applicant. All registrations shall expire on December thirty-one of each year. The application shall include the information required by section fifty-three.

A distributor shall not be required to register any brand of commercial feed which is already registered under the provisions of this section by another person.

Changes in the guarantee of either chemical or ingredient composition of a registered commercial feed may be permitted provided there is satisfactory evidence that such changes would not result in a lowering of the feeding value of the product for the purpose for which designed, and provided the commissioner or his deputy is notified of the change.

The commissioner or his deputy is empowered to refuse registration of any application not in compliance with the provisions of sections fifty-two to sixty, inclusive, and to cancel any registration subsequently found not to be in compliance with any provision thereof; provided, however, that no registration shall be refused or cancelled until the registrant shall have been given opportunity to be heard before the commissioner or his duly authorized assistant and to amend his application in order to comply with the law. The registration fee shall be twenty-five dollars.