. 2018 Oct 18;9:2457. doi: 10.3389/fmicb.2018.02457

Table 1.

Physical parameters, in-organic nutrient concentrations, and cultivable heterotrophic bacteria abundances over 70 rearing days in the semi-intensive and intensive farming system.

Day	10		20		30		40		50		60		70
System^a	S	T	S	T	S	T	S	T	S	T	S	T	S	T
Parameters^b
SPM^∗ (mg L^-1)	66.6 ± 8.0^a	68.7 ± 5.2^a	68.1 ± 4.9^a	70.3 ± 7.7^a	80.1 ± 12.2^b	91.5 ± 8.3^b	96.5 ± 5.7^c	122.0 ± 22.2^c	158.1 ± 4.0^d	202.6 ± 18.5^d	167.3 ± 5.5^d	187.6 ± 11.0^d	173.1 ± 2.2^d	171.3 ± 17.7^d
Chl a^∗ (mg L^-1)	13.34 ± 7.13^ac	5.47 ± 3.82^a	14.61 ± 1.49^ae	10.11 ± 5.04^ab	11.22 ± 0.96^ab	22.8 ± 19.8^ae	18.5 ± 5.5^ae	77.9 ± 32.1^e	20.7 ± 9.1^ae	63.5 ± 29.1^ce	30.9 ± 32.3^ae	33.7 ± 14.2^bce	16.9 ± 14.9^acd	68.1 ± 27.7^de
pH^∗	8.24 ± 0.04^b	8.18 ± 0.11^b	8.20 ± 0.14^ab	7.95 ± 0.07^ab	8.26 ± 0.22^ab	7.9 ± 0.1^ab	8.5 ± 0.1^b	8.0 ± 0.1^b	8.3 ± 0.2^ab	7.6 ± 0.5^ab	7.9 ± 0.1^a	7.8 ± 0.1^a	8.4 ± 0.5^b	8.1 ± 0.1^b
DO^∗ (mg L^-1)	6.13 ± 0.14	6.32 ± 0.1	6.4 ± 0.02	6.36 ± 0.13	5.90 ± 0.65	6.2 ± 0.1	6.1 ± 0.2	6.9 ± 0.8	5.9 ± 0.3	6.1 ± 0.2	5.7 ± 0.1	6.3 ± 0.2	5.8 ± 0.5	6.2 ± 0.3
Salinity^∗ (PSU)	35.37 ± 0.15^bd	38.43 ± 0.78^d	35.20 ± 0.69^ad	36.79 ± 0.50^cd	32.44 ± 3.26^a	35.9 ± 0.9^bd	33.7 ± 0.7^abc	35.0 ± 0.9^abc	33.4 ± 0.3^ab	35.8 ± 0.3^bd	33.6 ± 1.4^abc	34.1 ± 0.8^abc	34.6 ± 0.9^abc	33.6 ± 0.5^ab
Temperature (°C)	31.24 ± 0.41^cd	30.19 ± 0.50^bcd	28.08 ± 0.64^a	30.44 ± 0.18^bcd	31.61 ± 0.98^d	30.4 ± 1.6^bcd	29.6 ± 0.2^ac	28.9 ± 0.5^ab	31.0 ± 0.1^cd	30.1 ± 0.4^bcd	30.8 ± 0.8^cd	30.2 ± 0.1^bcd	30.7 ± 0.5^bcd	30.5 ± 0.4^bcd
Turbidity (NTU)	16.53 ± 10.69^ac	3.9 ± 2.21^a	24.5 ± 8.67^bc	9.93 ± 8.44^ab	35.87 ± 30.26^bc	22.9 ± 14.6^bc	27.0 ± 10.5^bc	25.7 ± 2.7^bc	25.9 ± 12.9^bc	25.3 ± 5.6^bc	27.6 ± 7.2^bc	30.2 ± 14.4^c	26.9 ± 9.2^bc	35.7 ± 15.9^c
Cultivable Bact. (log10 CFU mL^-1)
THB	4.75 ± 0.06^ac	4.42 ± 0.15^a	5.35 ± 0.04^bcd	4.65 ± 0.30^ab	6.29 ± 0.15^ef	5.50 ± 0.16^cd	5.99 ± 0.50^de	6.76 ± 0.20^eg	6.87 ± 0.69^fg	7.44 ± 0.19^g	7.53 ± 0.19^g	7.41 ± 0.36^g	7.47 ± 0.18^g	7.4 ± 0.1^g
TPPV	2.03 ± 0.56^a	2.13 ± 0.90^a	4.35 ± 0.36^bc	3.32 ± 0.32^ab	4.51 ± 0.19^bc	3.98 ± 0.18^b	3.85 ± 0.29^b	3.73 ± 0.41^b	3.85 ± 0.48^b	3.72 ± 0.15^b	4.16 ± 0.69^bc	5.41 ± 0.89^c	4.18 ± 0.42^bc	4.36 ± 0.7^bc
Nutrient (mg L^-1)
NH₄⁺	0.60 ± 0.37	0.436 ± 0.671	0.46 ± 0.71	0.15 ± 0.08	0.31 ± 0.23	0.26 ± 0.34	0.23 ± 0.19	0.26 ± 0.22	0.50 ± 0.07	0.37 ± 0.30	0.61 ± 0.858	0.835 ± 0.248	0.33 ± 0.34	0.36 ± 0.25
NO₂^-	0.004 ± 0.004	0.183 ± 0.292	0.004 ± 0.004	0.008 ± 0.007	0.021 ± 0.025	0.005 ± 0.003	0.007 ± 0.007	0.201 ± 0.334	0.016 ± 0.006	0.001 ± 0.001	0.002 ± 0.001	0.079 ± 0.113	0.013 ± 0.009	0.004 ± 0.003
NO₃^-	0.048 ± 0.06	0.075 ± 0.11	0.007 ± 0.005	0.097 ± 0.16	0.004 ± 0.003	0.027 ± 0.042	0.028 ± 0.02	0.213 ± 0.184	0.034 ± 0.025	0.014 ± 0.013	0.052 ± 0.04	0.307 ± 0.456	0.028 ± 0.026	0.284 ± 0.484
PO₄^3-	0.33 ± 0.31	0.53 ± 0.41	0.29 ± 0.20	0.50 ± 0.37	0.22 ± 0.17	0.22 ± 0.27	0.31 ± 0.38	0.72 ± 0.07	0.39 ± 0.26	0.11 ± 0.12	0.35 ± 0.36	0.59 ± 0.47	0.61 ± 0.08	0.31 ± 0.22
SiO₄^4-	1.424 ± 1.453	0.206 ± 0.191	0.179 ± 0.047	0.315 ± 0.253	1.217 ± 0.918	0.343 ± 0.134	0.565 ± 0.576	0.324 ± 0.245	0.898 ± 1.193	0.45 ± 0.36	0.636 ± 0.792	0.11 ± 0.07	0.623 ± 0.668	1.157 ± 1.413

Significant differences between systems at a significance threshold of 0.05 are indicated by asterisks; superscript letters indicate significant differences for the interaction system and day (p < 0.05). Data are shown as mean ± standard deviation. ^aS, semi-intensive system; T, intensive system. ^bSPM, suspended particulate matter; Chl a, chlorophyll a; THB, total heterotrophic bacteria; TPPV, total potential pathogenic bacteria.