Application of Antioxdant Enzymes as Biomarkers in Cultivability Assessment of Palaemonid Shrimps

The scope of the study was to explore and simulate some selected abiotic factors from the natural home of the shrimps (a tropical rainforest river) with a view to providing information required for sustainable shrimp husbandry.

Hypothesis: Abundance of shrimps is solely a function of the physico-chemical (abiotic) characteristics of the river.

Methodology: Water, sediment and shrimp samples were collected on monthly basis from the Osse River, in Edo State, Nigeria. The samples were collected between April and December, 2015; at night and early morning periods. The physico-chemical properties of the water and sediment samples were analyzed in the laboratory. The shrimp samples were identified, sorted, and counted. Analysis of variance was employed in analyzing the descriptive statistics of the physico-chemical properties. Sex distribution patterns amongst the shrimp species and the ratio of male to female distribution for each species was analyzed mathematically. Stress levels impacted by abiotic variables were investigated employing Cytochrome P450 mono-oxygenase (CYP450), Glutathione-S-Transferase (GST), Catalase (CAT), Superoxide dismutase (SOD) and Lipid Peroxide (LPO).

Results: Availability of the shrimps in the study area was: Macrobrachium vollenhovenii >Macrobrachium macrobrachion >Macrobrachium lux >Macrobrachium fellicinium >Nematopalaemon hastatus > Palaemon maculatus. The female shrimps outnumbered the males in among all the species captured from the natural environment. Order of abundance of shrimps in the river was Station 2 (41%) > Station 1 (32%) > Station 3 (16%) > Station 4 (11%).Abundance of shrimps at Station 2 can be attributed to the predominant abiotic factors such as flow rate (0.1 ± 0.01 m/s), depth (72.5 ± 3.1 cm, water pH (6.7- 7.5), water temperature (27.6 ± 1.07 °C), and primary productivity nutrients (oligotrophic). Laboratory results conform to field observations on the basis of depth having greater impacts on the organisms than flow rate.

Conclusion: Palaemonid shrimps are littoral organisms which have considerable cultivability. Depth of 72 cm and flow rate of 0.1 m/s are recommended for aquaculture of the shrimps. Notwithstanding, sufficient information about their feeding habits and breeding conditions are imperative.