<PAGE>
                                                                  EXHIBIT 10.1.3

                                                                  EXECUTION COPY




        THIRD AMENDMENT TO AMENDED AND RESTATED REVOLVING CREDIT, CAPITAL
                     EXPENDITURE LINE AND SECURITY AGREEMENT


      THIS THIRD AMENDMENT TO AMENDED AND RESTATED REVOLVING CREDIT, CAPITAL
EXPENDITURE LINE AND SECURITY AGREEMENT (the "Agreement") is entered into on the
8th day of August, 2003 by and among PHIBRO ANIMAL HEALTH CORPORATION (formerly
known as Philipp Brothers Chemicals, Inc.), a corporation organized under the
laws of the State of New York, ("Borrower"), Phibro-Tech, Inc., a corporation
organized under the laws of the State of Delaware, C P Chemicals, Inc., a
corporation organized under the laws of the State of New Jersey, The Prince
Manufacturing Company, a corporation organized under the laws of the State of
Illinois (as an individual entity and as successor by merger to The Prince
Manufacturing Company, a corporation organized under the laws of the State of
Pennsylvania), Prince Agriproducts, Inc., a corporation organized under the laws
of the State of Delaware, Mineral Resource Technologies, Inc., a corporation
organized under the laws of the State of Delaware (successor by merger of
Mineral Resource Technologies, L.L.C. which merged into MRT Management Corp.),
Phibro-Chem, Inc., a corporation organized under the laws of the State of New
Jersey, PhibroChemicals, Inc., a corporation organized under the laws of the
State of New York, Western Magnesium Corp., a corporation organized under the
laws of the State of California, Phibro Animal Health Holdings, Inc., a
corporation organized under the laws of Delaware, and Phibro Animal Health U.S.,
Inc., a corporation organized under the laws of Delaware (each a "Guarantor" and
collectively "Guarantors"), the financial institutions which are now or which
hereafter become a party hereto (collectively, the "Lenders" and individually a
"Lender") and PNC BANK, NATIONAL ASSOCIATION, a national banking association
("PNC"), as agent for Lenders (PNC, in such capacity, the "Agent").

                                    RECITALS

      Whereas, on August 19, 1998, PNC, the Borrower and certain Guarantors
entered into a Revolving Credit, Acquisition Term Loan and Security Agreement
(as such has been amended, supplemented and/or restated until November 28, 2000,
the "Original Loan Agreement"), pursuant to which certain Lenders extended
various credit facilities in favor of the Borrower;

      Whereas, on November 29, 2000, Borrower, Guarantors and Lenders amended
and restated the Original Loan Agreement and entered into an Amended and
Restated Revolving Credit, Capital Expenditure Line and Security Agreement (as
may be amended, supplemented and/or restated, the "Loan Agreement"), pursuant to
which the Lenders extended various credit facilities in the aggregate amount of
$85,000,000 in favor of the Borrower;

      Whereas, on September 28, 2001, Borrower, Guarantors and Lenders agreed to
modify the terms of the Loan Agreement as set forth in the First Amendment to
Amended and Restated Revolving Credit, Capital Expenditure Line and Security
Agreement;

      Whereas, on October 23, 2002, Borrower, Guarantors and Lenders agreed to
modify the terms of the Loan Agreement as set forth in the Second Amendment to
Amended and Restated Revolving Credit, Capital Expenditure Line and Security
Agreement;

      Whereas, Borrower, Guarantors and Lenders have agreed to further modify
the terms of the Loan Agreement as set forth in this Agreement.

      Now, therefore, in consideration of Lender's continued extension of credit
and the agreements contained herein, the parties agree as follows:

                                    AGREEMENT

      1) ACKNOWLEDGMENT OF BALANCE. Borrower acknowledges that the most recent
statement of account sent to Borrower with respect to the Obligations is
correct.
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                                                                  EXECUTION COPY

      2) MODIFICATIONS. The Loan Agreement and the Other Documents be and hereby
are modified as follows:

      (A) The name "Philipp Brothers Chemicals, Inc." throughout the Loan
      Agreement and the Other Documents is hereby deleted and replaced with the
      name "Phibro Animal Health Corporation (formerly known as Philipp Brothers
      Chemicals, Inc.)".

3) ACKNOWLEDGMENTS. Borrower acknowledges and represents that:

      (A) the Loan Agreement and Other Documents, as amended hereby, are in full
force and effect without any defense, claim, counterclaim, right or claim of
set-off;

      (B) to the best of its knowledge, no default by the Agent or Lenders in
the performance of their duties under the Loan Agreement or the Other Documents
has occurred;

      (C) all representations and warranties of the Borrower contained herein
and in the Other Documents are true and correct in all material respects as of
this date, except for any representation or warranty that specifically refers to
an earlier date and except to the extent that the Agent and the Lenders have
been notified by the Borrower that any representation or warranty is not correct
and the Required Lenders have explicitly waived in writing compliance with such
representation or warranty (which waiver is hereby granted) and except for
changes not prohibited by the terms of the Loan Agreement;

      (D) Borrower has taken all necessary corporate or company action to
authorize the execution and delivery of this Agreement; and

      (E) this Agreement is a modification of an existing obligation and is not
a novation.

4)    PRECONDITIONS. The Borrower shall deliver to the Agent the following: (a)
      an executed Third Amendment to Amended and Restated Revolving Credit,
      Capital Expenditure Line and Security Agreement, (b) evidence that the
      Borrower has filed all necessary documentation with regard to the changing
      of its name from Philipp Brothers Chemicals, Inc. to Phibro Animal Health
      Corporation in its State of incorporation and in all jurisdiction which it
      is qualified to do business and (c) an executed resolution of the Borrower
      authorizing the transaction described herein. It is understood and agreed
      that Borrower shall pay all fees and costs incurred by Lenders in entering
      into this Agreement and the other documents executed in connection
      herewith, including but not limited to all reasonable attorney fees and
      expenses of Lenders' counsel.

5)    MISCELLANEOUS. This Agreement shall be construed in accordance with and
      governed by the laws of the State of New Jersey, without reference to that
      state's conflicts of law principles. This Agreement and the Other
      Documents constitute the sole agreement of the parties with respect to the
      subject matter hereof and thereof and supersede all oral negotiations and
      prior writings with respect to the subject matter hereof and thereof. No
      amendment of this Agreement, and no waiver of any one or more of the
      provisions hereof shall be effective unless set forth in writing and
      signed by the parties hereto. The illegality, unenforceability or
      inconsistency of any provision of this Agreement shall not in any way
      affect or impair the legality, enforceability or consistency of the
      remaining provisions of this Agreement or the Other Documents. This
      Agreement and the Other Documents are intended to be consistent. However,
      in the event of any inconsistencies among this Agreement and either the
      Loan Agreement or any of the Other Documents, the terms of this Agreement,
      then the Loan Agreement, shall control. This Agreement may be executed in
      any number of counterparts and by the different parties on separate
      counterparts. Each such counterpart shall be deemed an original, but all
      such counterparts shall together constitute one and the same agreement.



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                                                                  EXECUTION COPY

6)    DEFINITIONS. The terms used herein and not otherwise defined or modified
      herein shall have the meanings ascribed to them in the Loan Agreement. The
      terms used herein and not otherwise defined or modified herein or defined
      in the Loan Agreement shall have the meanings ascribed to them by the
      Uniform Commercial Code as enacted in New Jersey.

IN WITNESS WHEREOF, the undersigned have signed and sealed this Agreement the
day and year first above written.

<TABLE>
<S>                                             <C>
BORROWER:

ATTEST:                                         PHIBRO ANIMAL HEALTH CORPORATION
                                                (formerly known as Philipp Brothers Chemicals, Inc.)


BY:  /s/ David C. Storbeck                      By:  /s/ Richard G. Johnson
   ---------------------------------------           --------------------------------------------------
    David C. Storbeck, Assistant Secretary           Richard G.  Johnson, Vice President
                                                     One Parker Plaza
                                                     Fort Lee, N.J. 07024

GUARANTORS:

ATTEST:                                         PHIBRO-TECH, INC.


BY: /s/ David C. Storbeck                       By:  /s/ W. Dwight Glover
    --------------------------------------           --------------------------------------------------
       David  C. Storbeck, Vice President            W. Dwight Glover, President
                                                     One Parker Plaza
                                                     Fort Lee, N.J. 07024


ATTEST:                                         C P CHEMICALS, INC.


BY: /s/ David C. Storbeck                       By:  /s/ Jack C. Bendheim
    --------------------------------------           --------------------------------------------------
      David  C. Storbeck, Vice President             Jack C. Bendheim, President
                                                     One Parker Plaza
                                                     Fort Lee, N.J. 07024

ATTEST:                                         THE PRINCE MANUFACTURING COMPANY (IL)

                                                (as an individual entity and as successor by merger to
                                                The Prince Manufacturing Company, a corporation
                                                organized under the laws of the State of Pennsylvania,)

BY: /s/ David C. Storbeck                       By: /s/ Marvin Sussman
    --------------------------------------          --------------------------------------------------------------
      David C. Storbeck, Vice President              Marvin Sussman,  President
                                                     One Prince Plaza
                                                     P.O. Box 1009
                                                     Quincy, Il. 62306
</TABLE>



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<PAGE>
                                                                  EXECUTION COPY

<TABLE>
<S>                                                  <C>
ATTEST:                                              PRINCE AGRIPRODUCTS, INC.


BY: /s/ David C. Storbeck                             By: /s/ Marvin Sussman
    --------------------------------------------          --------------------------------------------------------
      David C. Storbeck, Vice President                    Marvin Sussman, President
                                                           One Prince Plaza
                                                           P.O. Box 1009
                                                           Quincy, Il. 62306


ATTEST:                                              Mineral Resource Technologies, Inc.
                                                     (successor by merger of Mineral Resource Technologies, L.L.C.
                                                      which merged into MRT Management Corp.)


BY: /s/ Hugh Shannonhouse                            By: /s/ David C. Storbeck
    --------------------------------                 -------------------------------------------------------------
       Hugh Shannonhouse, President                      David C. Storbeck, Vice President
                                                         2700 Research Forest Drive
                                                         Suite 150
                                                         The Woodlands, TX 77381


ATTEST:                                              PHIBRO-CHEM, INC.


BY: /s/ David C. Storbeck                            By: /s/ Jack C. Bendheim
    --------------------------------------------         ---------------------------------------------------------
      Davic C. Storbeck, Vice President                  Jack C. Bendheim, President
                                                         One Parker Plaza
                                                         Fort Lee, N.J. 07024


ATTEST:                                              PHIBROCHEMICALS, INC.


BY: /s/ David C. Storbeck                            By: /s/ Jack C. Bendheim
   --------------------------------------------          ---------------------------------------------------------
      David C. Storbeck, Vice President                  Jack C. Bendheim, President
                                                         One Parker Plaza
                                                         Fort Lee, N.J. 07024

ATTEST:                                              WESTERN MAGNESIUM CORP.


BY: /s/ David C. Storbeck                            By: Jack C. Bendheim
    --------------------------------------------         --------------------------------------------------------
      David C. Storbeck, Vice President                  Jack, C. Bendheim, President
                                                         One Parker Plaza
                                                         Fort Lee, N.J. 07024
</TABLE>





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<PAGE>
                                                                  EXECUTION COPY

<TABLE>
<S>                                                      <C>
ATTEST:                                                  PHIBRO ANIMAL HEALTH HOLDINGS, INC.


BY: /s/ David C. Storbeck                                By:/s/ Marvin Sussman
    --------------------------------------------            --------------------------------------------------
      David C. Storbeck,  Vice President                     Marvin Sussman,  President
                                                             One Parker Plaza
                                                             Fort Lee, N.J. 07024


ATTEST:                                                  PHIBRO ANIMAL HEALTH  U.S., INC.


BY: /s/ David C. Storbeck                                By:/s/ Marvin Sussman
    --------------------------------------------            --------------------------------------------------
      David C. Storbeck, Vice President                     Marvin Sussman, President
                                                            One Parker Plaza
                                                            Fort Lee, N.J. 07024


LENDERS:

ATTEST:                                                  PNC BANK, NATIONAL ASSOCIATION, as Lender and as
                                                         Agent


                                                         By:__________________________________________________
------------------------------------------------
                                                            Name:  Michelle Stanley-Nurse
                                                            Title:  Vice President
                                                            Address:  70 East 55th Street, 14th Floor
                                                                      New York, New York  10022
                                                         Commitment Percentage:  41.1764705882%


                                                         BANK OF AMERICA, N. A., as Lender


                                                         By: /s/ Edmundo E. Kahn
                                                             -------------------------------------------------
                                                             Name: Edmundo E. Kahn
                                                             Title: Vice President
                                                             Address:   335 Madison Avenue
                                                                        6th Floor
                                                                        New York, New York 10017
                                                         Commitment Percentage:  29.4117647059%


                                                         GENERAL ELECTRIC CAPITAL CORPORATION, as
                                                         Lender


                                                         By: /s/ Susan Timmerman
                                                             --------------------------------------------------
                                                             Name:    Susan Timmerman
                                                             Title:   Sr. Risk Manager
                                                             Address: 401 Merritt 7
                                                                      Norwalk, CT 06854

                                                         Commitment Percentage:  29.4117647059%

</TABLE>

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