. 2022 Feb 15;12:19. doi: 10.1186/s13568-022-01354-5

Table 1.

The optimized results of compound nitrogen source

Nitrogen source	C. butyricum viable counts (× 10⁷ cfu/mL)	C. butyricum spores (× 10⁷ cfu/mL)	Spore rate (%)
Group1 Group2 Group3 Group4 Group5 Group6 Group7 Group8 Group9 Contrast	4.8 7.1 3.1 4.0 5.0 1.8 4.5 4.2 2.3 5.6	4.1 5.8 2.4 2.2 1.7 0.9 2.1 2.7 1.3 3.5	85.4 81.7 77.4 55.0 34.0 50.0 46.7 64.3 56.5 62.5

Nitrogen source

C. butyricum viable counts (× 10⁷ cfu/mL)

C. butyricum spores (× 10⁷ cfu/mL)

Spore rate (%)

Group1

Group2

Group3

Group4

Group5

Group6

Group7

Group8

Group9

Contrast

4.8

7.1

3.1

4.0

5.0

1.8

4.5

4.2

2.3

5.6

4.1

5.8

2.4

2.2

1.7

0.9

2.1

2.7

1.3

3.5

85.4

81.7

77.4

55.0

34.0

50.0

46.7

64.3

56.5

62.5

Group1 to 9 indicate the combination of corn steep powder with soybean meal powder, peptone, beef paste, fishmeal, tryptone, yeast extract, yeast, NH₄Cl and (NH₄)₂SO₄ respectively. The ratio of corn steep powder to other nitrogen sources is 1:1, and the total nitrogen source content is 15 g/L. 15 g/L corn steep powder was used as control