Abstract:
The bacterial content of the water of Metapenaeus afinis and Macrobrachium nipponense juvenile shrimp cultured in two salinities (3 and 15 g.L-1) were observed during 45 days. The initial and final weights of M. afinis were (0.939 ± 0.069 and 1.581 ± 0.183 g) in 3 g.L -1, and (0.939 ± 0.065 and 2.274 ± 0.294 g) in 15 g.L-1. While for M. nipponense, it was (0.914 ± 0.086 and 1.308 ± 0.070 g) in 3 g.L-1, and (0.908 ± 0.070 and 1.086 ± 0.107 g) in 15 g.L-1. The environmental factors were temperature 24-29 °C, acidity 7-8, and dissolved oxygen 5-10 g.L-1. Bacterial contamination (CFU m.L-1 106) was evident in treatment D and included four types of bacteria: Bacillus spp., Escherchia coli, Staphylococcus spp., Streptococcus spp., and Enterococcus spp. The survival rates of M. afinis during diferent breeding periods in the two salinities remained as follows: (93.33 ± 5.77, 9.00 ± 10.00, 83.33 ± 5.77 %) and (93.33 ± 5.77, 90.00 ± 10.00, and 86.67 ±5.77 %), respectively. The survival rates of M. nipponense during diferent breeding periods in the two salinities are as follows: (100 ± 0, 93.33 ± 5.77, 93.33 ± 5.77 %), (60.00 ± 10.00, 50.00 ± 10.00, and 43.33 ± 5.77 %), respectively. The results of the statistical analysis showed that the shrimp M. afinis (A) in salinity 3 was significant (P>0.05) between the average weights of all the average weights during all periods, while there were no significant diferences (P<0.05) between the average weights of the 15 and 30-day periods. In treatment (B) 15, significant diferences (P>0.05) were found between all periods of the experiment. Shrimp M. nipponense in salinity 3 (C) treatment, there are significant diferences (P>0.05) between the initial weight and all periods, but there were no significant diferences (P<0.05) between it and the first period of 15 days, also there were no diferences (P<0.05) between the periods 30 and 45 days. While in the treatment of salinity 15 (D), significant diferences (P>0.05) were found between the last period (45 days) and the average weight of the initial and 15 days, but there were no significant diferences (P<0.05) between the other periods. And the total bacterial content found significant diferences (P>0.05) between treatment D and the combination of treatments A, B, and C, and there were no significant diferences (P<0.05) between them.
Keywords:
Aquaculture
,
Water quality
,
Mesohaline
,
Oligohaline