1. A composition for animal cell culture, which comprises an amino acid source and a-ketoglutaric acid, and wherein the composition satisfies the following conditions (A) and/or (B); (A) the a-ketoglutaric acid is a salt of a-ketoglutaric acid; and/or (B) the amino acid source is free L-cysteine anhydrate. The composition according to claim 1, wherein the composition satisfies at least the condition (A).

3. The composition according to claim 1 or 2, wherein the composition is a powder form.

4. The composition according to any one of claims 1 to 3, wherein the composition is a culture medium or culture medium additive.

5. The composition according to claim 4, wherein the culture medium is a basal medium, a feed medium, or a perfusion medium.

6. The composition according to any one of claims 1 to 5, wherein the salt of a-ketoglutaric acid is an alkali metal salt or alkaline earth metal salt of a-ketoglutaric acid.

7. The composition according to any one of claims 1 to 6, wherein the salt of a-ketoglutaric acid is a sodium salt or potassium salt of a-ketoglutaric acid.

8. The composition according to any one of claims 1 to 7, wherein the salt of a-ketoglutaric acid is monosodium a-ketoglutarate or disodium a-ketoglutarate.

9. The composition according to any one of claims 1 to 8, wherein the amino acid source is cysteine, glycine, asparagine, glutamic acid, lysine, phenylalanine, methionine, ornithine, tyrosine, or a glycine-containing dipeptide.

10. The composition according to claim 9, wherein the composition satisfies one or more conditions selected from the group consisting of the following conditions (1) to (10): (1) the cysteine is free L-cysteine or L-cysteine hydrochloride; (2) the glycine is free glycine or free glycyl-L-tyrosine; (3) the asparagine is free L-asparagine; (4) the glutamic acid is monosodium L-glutamate; (5) the lysine is L-lysine hydrochloride; (6) the phenylalanine is free L-phenylalanine; (7) the methionine is free L-methionine; (8) the ornithine is L-ornithine hydrochloride; (9) the tyrosine is L-tyrosine disodium salt; and (10) the glycine-containing dipeptide is free glycyl-L-tyrosine.

11. The composition according to claim 9 or 10, wherein the composition satisfies one or more conditions selected from the group consisting of the following conditions (1a) to (10a): (1a) the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate; (2a) the glycine is free glycine or free glycyl-L-tyrosine; (3a) the asparagine is free L-asparagine monohydrate; (4a) the glutamic acid is monosodium L-glutamate monohydrate; (5a) the lysine is L-lysine hydrochloride; (6a) the phenylalanine is free L-phenylalanine; (7a) the methionine is free L-methionine; (8a) the ornithine is L-ornithine hydrochloride; (9a) the tyrosine is L-tyrosine disodium salt dihydrate; and (10a) the glycine-containing dipeptide is free glycyl-L-tyrosine dihydrate.

12. The composition according to any one of claims 1 to 11, wherein the amino acid source is cysteine.

13. The composition according to any one of claims 9 to 12, wherein the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate.

14. The composition according to any one of claims 9 to 13, wherein the cysteine is free L-cysteine anhydrous.

15. The composition according to any one of claims 1 to 14, wherein content of the a-ketoglutaric acid is 1 to 20 times content of the amino acid source in terms of molar (1a) the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate; (2a) the glycine is free glycine or free glycyl-L-tyrosine; (3a) the asparagine is free L-asparagine monohydrate; (4a) the glutamic acid is monosodium L-glutamate monohydrate; (5a) the lysine is L-lysine hydrochloride; (6a) the phenylalanine is free L-phenylalanine; (7a) the methionine is free L-methionine; (8a) the ornithine is L-ornithine hydrochloride; (9a) the tyrosine is L-tyrosine disodium salt dihydrate; and (10a) the glycine-containing dipeptide is free glycyl-L-tyrosine dihydrate. The use according to any one of claims 19 to 22, wherein the amino acid source is cysteine.

24. Use of a salt of a-ketoglutaric acid for preventing decrease in cysteine content in a composition containing cysteine.

25. The use according to any one of claims 19 to 24, wherein the salt of a-ketoglutaric acid is an alkali metal salt or alkaline earth metal salt of a-ketoglutaric acid.

26. The use according to any one of claims 19 to 25, wherein the salt of a-ketoglutaric acid is a sodium salt or potassium salt of a-ketoglutaric acid.

27. The use according to any one of claims 19 to 26, wherein the salt of a-ketoglutaric acid is monosodium a-ketoglutarate or disodium a-ketoglutarate.

28. The use according to any one of claims 20 to 27, wherein the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate.

29. The use according to any one of claims 20 to 28, wherein the cysteine is free L-cysteine anhydrous.

30. The use according to any one of claims 19 to 29, wherein the salt of a-ketoglutaric acid is used so that content of the salt of a-ketoglutaric acid in the composition is 1 to 20 times content of the amino acid source or the cysteine in the composition in terms of molar ratio.

31. A method for producing a composition for animal cell culture, wherein the composition is the composition according to any one of claims 1 to 15, and the method comprises mixing the amino acid source and the a-ketoglutaric acid.

WE CLAIM:
1. A composition for animal cell culture, which
comprises an amino acid source and a-ketoglutaric acid, and wherein the composition satisfies the following conditions (A) and/or (B);
(A) the a-ketoglutaric acid is a salt of a-ketoglutaric acid; and/or
(B) the amino acid source is free L-cysteine anhydrate.
The composition according to claim 1, wherein the composition satisfies at least the condition (A).
3. The composition according to claim 1 or 2, wherein the composition is a powder form.
4. The composition according to any one of claims 1 to 3, wherein the composition is a culture medium or culture medium additive.
5. The composition according to claim 4, wherein the culture medium is a basal medium, a feed medium, or a perfusion medium.
6. The composition according to any one of claims 1 to 5, wherein the salt of a-ketoglutaric acid is an alkali metal salt or alkaline earth metal salt of a-ketoglutaric acid.
7. The composition according to any one of claims 1 to 6, wherein the salt of a-ketoglutaric acid is a sodium salt or potassium salt of a-ketoglutaric acid.
8. The composition according to any one of claims 1 to 7, wherein the salt of a-ketoglutaric acid is monosodium a-ketoglutarate or disodium a-ketoglutarate.
9. The composition according to any one of claims 1 to 8, wherein the amino acid source is cysteine, glycine, asparagine, glutamic acid, lysine, phenylalanine, methionine, ornithine, tyrosine, or a glycine-containing dipeptide.
10. The composition according to claim 9, wherein the composition satisfies one or more conditions selected from the group consisting of the following conditions (1) to (10):
(1) the cysteine is free L-cysteine or L-cysteine hydrochloride;
(2) the glycine is free glycine or free glycyl-L-tyrosine;
(3) the asparagine is free L-asparagine;
(4) the glutamic acid is monosodium L-glutamate;
(5) the lysine is L-lysine hydrochloride;
(6) the phenylalanine is free L-phenylalanine;
(7) the methionine is free L-methionine;
(8) the ornithine is L-ornithine hydrochloride;
(9) the tyrosine is L-tyrosine disodium salt; and
(10) the glycine-containing dipeptide is free glycyl-L-tyrosine.
11. The composition according to claim 9 or 10, wherein the composition satisfies one or more conditions selected from the group consisting of the following conditions (1a) to (10a):
(1a) the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate;
(2a) the glycine is free glycine or free glycyl-L-tyrosine;
(3a) the asparagine is free L-asparagine monohydrate;
(4a) the glutamic acid is monosodium L-glutamate monohydrate;
(5a) the lysine is L-lysine hydrochloride;
(6a) the phenylalanine is free L-phenylalanine;
(7a) the methionine is free L-methionine;
(8a) the ornithine is L-ornithine hydrochloride;
(9a) the tyrosine is L-tyrosine disodium salt dihydrate; and
(10a) the glycine-containing dipeptide is free glycyl-L-tyrosine dihydrate.
12. The composition according to any one of claims 1 to 11, wherein the amino acid source is cysteine.
13. The composition according to any one of claims 9 to 12, wherein the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate.
14. The composition according to any one of claims 9 to 13, wherein the cysteine is free L-cysteine anhydrous.
15. The composition according to any one of claims 1 to 14, wherein content of the a-ketoglutaric acid is 1 to 20 times content of the amino acid source in terms of molar
(1a) the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate; (2a) the glycine is free glycine or free glycyl-L-tyrosine;
(3a) the asparagine is free L-asparagine monohydrate;
(4a) the glutamic acid is monosodium L-glutamate monohydrate;
(5a) the lysine is L-lysine hydrochloride;
(6a) the phenylalanine is free L-phenylalanine;
(7a) the methionine is free L-methionine;
(8a) the ornithine is L-ornithine hydrochloride;
(9a) the tyrosine is L-tyrosine disodium salt dihydrate; and
(10a) the glycine-containing dipeptide is free glycyl-L-tyrosine dihydrate.
The use according to any one of claims 19 to 22, wherein the amino acid source is cysteine.
24. Use of a salt of a-ketoglutaric acid for preventing decrease in cysteine content in a composition containing cysteine.
25. The use according to any one of claims 19 to 24, wherein the salt of a-ketoglutaric acid is an alkali metal salt or alkaline earth metal salt of a-ketoglutaric acid.
26. The use according to any one of claims 19 to 25, wherein the salt of a-ketoglutaric acid is a sodium salt or potassium salt of a-ketoglutaric acid.
27. The use according to any one of claims 19 to 26, wherein the salt of a-ketoglutaric acid is monosodium a-ketoglutarate or disodium a-ketoglutarate.
28. The use according to any one of claims 20 to 27, wherein the cysteine is free L-cysteine anhydrous or L-cysteine hydrochloride monohydrate.
29. The use according to any one of claims 20 to 28, wherein the cysteine is free L-cysteine anhydrous.
30. The use according to any one of claims 19 to 29, wherein the salt of a-ketoglutaric acid is used so that content of the salt of a-ketoglutaric acid in the composition is 1 to 20 times content of the amino acid source or the cysteine in the composition in terms of molar ratio.
31. A method for producing a composition for animal cell culture, wherein
the composition is the composition according to any one of claims 1 to 15, and the method comprises mixing the amino acid source and the a-ketoglutaric acid.