Antibacterial activity of muscle wall extracts of sea cucumber (Stichopus horrens) from Chabahar coastal area, Iran, against pathogenic bacteria in rainbow trout (Oncorhynchus mykiss)

Figures & data

Figure 1. Transverse slicing of S. horrens.

Table 1. Phytochemical compositions of S. horrens extract (number of samples = 3).

Phytochemical compositions	Quantitative (mean ± SD)
Sterols (mg/g DW)	3.78 ± 2.16
Flavonoids (mg QE/g DW)	2.65 ± 0.91
Phenols (mg GE/g DW)	14.13 ± 1.83
Saponins (mg/g DW)	4.45 ± 0.87

Figure 2. Effect of methanol, acetone, and ethyl acetate extracts on the growth inhibition of Y. ruckeri.

Table 2. Inhibition zone diameter (mm) in different concentrations of three S. horrens extracts, tetracycline, and enrofloxacin on all tested bacteria.

Bacteria				Different concentrations of three extracts (mg/mL)
	Methanol			Acetone			Ethyl acetate			Antibiotic (30 µg)
	4	8	12	4	8	12	4	8	12	Tetracycline	Enrofloxacin
Y. ruckeri	−	−	8.16 ± 0.15^a	−	8.10 ± 0.1^b	11.10 ± 0.1^b	−	10 ± 0.10^a	12.03 ± 0.15^a	18.03 ± 0.15^b	10 ± 0.2^c
S. iniae	−	−	−	−	−	−	−	8 ± 0.20^b	12 ± 0.10^a	7 ± 0.2^c	17.03 ± 0.15^a
A. hydrophila	−	−	−	8.03 ± 0.15^a	11.16 ± 0.15^a	13.03 ± 0.15^a	−	7.10 ± 0.1^c	8 ± 0.10^c	19.03 ± 0.15^a	7.03 ± 0.15^d
L. garvieae	−	−	−	−	−	−	−	5.96 ± 0.15^d	10 ± 0.10^b	6 ± 0.2^d	16.03 ± 0.15^b

Values given as mm for different concentrations of three extracts (mean ± SD (n = 3)). Different letters in the same columns indicate significant differences between bacteria (p < 0.05). −: not determined.

Figure 3. OD-600 nm absorption of tested bacterial strains in different concentrations of three S. horrens extracts.

Table 3. MIC, MBC values (mg/mL), and MBC/MIC ratio of three S. horrens extracts on all bacteria.

Bacterial strains	MIC and MBC values (mg/mL) and MBC/MIC ratio
	Methanol			Acetone			Ethyl acetate
	MIC	MBC	MBC/MIC	MIC	MBC	MBC/MIC	MIC	MBC	MBC/MIC
Y. ruckeri	0.625	5	8	0.625	2.5	4	1.25	1.25	1
S. iniae	−	−	−	−	−	−	0.625	1.25	2
A. hydrophila	−	−	−	1.25	2.5	2	2.5	2.5	1
L. garvieae	−	−	−	−	−	−	0.625	2.5	4

−: not determined.