A method of preparing a feed additive composition comprising: admixing at least one proline tolerant tripeptidyl peptidase predominantly having exopeptidase activity wherein said proline tolerant tripeptidyl peptidase is capable of cleaving tri-peptides from the N-terminus of peptides having (i) Proline at P1; and An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids at P1; and/or (ii) (a') Proline at P1'; and (b') An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids or amines at P1'; and one or more ingredients selected from the group consisting of: a salt, polyol including sorbitol and glycerol, wheat or a wheat component, sodium acetate, sodium acetate trihydrate, potassium sorbate Talc, polyvinyl alcohol, benzoate, sorbiate, 1,3-propane diol, glucose, parabens, sodium chloride, citrate, metabisulfite, formate or a combination thereof and optionally packaging, wherein the at least one proline tolerant tripeptidyl peptidase: (a) comprises the amino acid sequence SEQ ID No. 29, SEQ ID No. 1, SEQ ID No. 2 or a functional fragment thereof that retains said peptidase activity; (b) comprises an amino acid having at least 80% or at least 90% identity to SEQ ID No. 29, SEQ ID No. 1, SEQ ID No. 2 or a functional fragment thereof that retains said peptidase activity; (c) is encoded by a nucleotide sequence comprising the sequence SEQ ID No. 56; (d) is encoded by a nucleotide sequence comprising at least 80% or at least 90% sequence identity to SEQ ID No. 56; (e) is encoded by a nucleotide sequence which hybridises to SEQ ID No. 56 under high stringency conditions; or (f) is encoded by a nucleotide sequence which differs from SEQ ID No. 56 due to degeneracy of the genetic code. admixing at least one proline tolerant tripeptidyl peptidase predominantly having exopeptidase activity wherein said proline tolerant tripeptidyl peptidase is capable of cleaving tri-peptides from the N-terminus of peptides having (i) Proline at P1; and An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids at P1; and/or (ii) (a') Proline at P1'; and (b') An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids or amines at P1'; and (i) Proline at P1; and An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids at P1; and/or Proline at P1; and An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids at P1; and/or (ii) (a') Proline at P1'; and (b') An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids or amines at P1'; and (a') Proline at P1'; and (b') An amino acid selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine or synthetic amino acids or amines at P1'; and one or more ingredients selected from the group consisting of: a salt, polyol including sorbitol and glycerol, wheat or a wheat component, sodium acetate, sodium acetate trihydrate, potassium sorbate Talc, polyvinyl alcohol, benzoate, sorbiate, 1,3-propane diol, glucose, parabens, sodium chloride, citrate, metabisulfite, formate or a combination thereof and (a) comprises the amino acid sequence SEQ ID No. 29, SEQ ID No. 1, SEQ ID No. 2 or a functional fragment thereof that retains said peptidase activity; (b) comprises an amino acid having at least 80% or at least 90% identity to SEQ ID No. 29, SEQ ID No. 1, SEQ ID No. 2 or a functional fragment thereof that retains said peptidase activity; (c) is encoded by a nucleotide sequence comprising the sequence SEQ ID No. 56; (d) is encoded by a nucleotide sequence comprising at least 80% or at least 90% sequence identity to SEQ ID No. 56; (e) is encoded by a nucleotide sequence which hybridises to SEQ ID No. 56 under high stringency conditions; or (f) is encoded by a nucleotide sequence which differs from SEQ ID No. 56 due to degeneracy of the genetic code.