Growth, biochemical, antioxidants, metabolic enzymes and hemocytes population of the shrimp Litopenaeus vannamei exposed to acidified seawater

Acidification in the marine environment has become a global issue that creates serious threats to marine organisms. In the present study, we evaluated the effect of CO₂ driven acidification on the shrimp Litopenaeus vannamei post-larvae (PL). L. vannamei PL were exposed to six different CO₂ driven acidified seawater, such as 8.2 (control), pH 7.8 (IPCC-predicted ocean pH by 2100), 7.6, 7.4, 7.2 and 7.0 with corresponding pCO₂ level of 380.66, 557.53, 878.55, 1355.48, 2129.46, and 3312.12 μatm for seven weeks. At the end of the acidification experiment, results revealed that the survival, growth, feed index, biochemical constituents, chitin, minerals (Na, K, and Ca), and hemocyte populations of shrimps were found to be significantly decreased in CO₂ driven acidified seawater which indicates the negative impacts of acidified seawater on these parameters in L. vannamei. Further, the level of antioxidants, lipid peroxidation, and metabolic enzymes were significantly higher in the muscle of shrimps exposed to acidified seawater suggests that the L. vannamei under oxidative stress and metabolic stress. Among the various acidified seawater tested, pH 7.6 to 7.0 produced a significantly adverse effect on shrimps. Hence, the present study concluded that the elevated level of seawater acidification can produce harmful effects on the biology and physiology of the commercially important shrimp L. vannamei PL.

Bioaccumulation of metals in mangroves and salt marshes collected from Tuticorin coast of Gulf of Mannar marine biosphere reserve, Southeastern India

Three species of mangroves and six species of salt marshes were collected from various locations along the Tuticorin coast for the estimation of metals like Cu, Cd, Pb, and Zn. The bioaccumulation of metals in mangroves is in the order of Cu > Pb > Zn > Cd, and the season-wise accumulation was higher in monsoon followed by summer, post-monsoon, and pre-monsoon seasons. The accumulation of metals in mangroves showed higher in Rhizophoraapiculata followed by Avicenniamarina, and Rhizophoramucronata. The concentration of metals in salt marshes is in the order of Pb > Zn > Cu > Cd, and the species-wise accumulation showed in the order of Suaeda maritime > Ipomoea sp. > Suaeda sp. > Spinifix littoreous > Sesuvium portacastrum > Ipomoea pes-capras. BAF in salt marhes and mangroves is as Cd < Pb < Cu < Zn and Cd < Cu < Pb < Zn, respectively.

Assessment of Heavy Metals Pollution in Noyyal and Chinnar Rivers, Western Ghats of Tamil Nadu, India with Reference to Crabs (Gecarcinucidae)-A Baseline Study

In the present study, heavy metals (Cd, Cu, Pb, and Zn) level in the water, sediment, and crabs were analyzed from Noyyal and Chinnar Rivers of the Western Ghats in Tamil Nadu, India. Based on our results, Noyyal River is considered as polluted environment due to the discharge of contaminants by various anthropogenic activities, whereas, Chinnar River maintained as unpolluted one due to its tributary nature of Noyyal River located in Western Ghats hills. The results showed that the heavy metals in water and sediments were higher in Noyyal River. Also, the level of bioaccumulation of studied metals and biochemical constituents were higher in the crab Spiralothelphusa hydrodroma sampled from Noyyal River than Barytelphusa cunicularis collected from Chinnar River. The present findings revealed that the crab sampled from Noyyal River had elevated heavy metals which lead to a significant increase in biochemical constituents to overcome the stress.

Bioaccumulation of heavy metals, antioxidants, and metabolic enzymes in the crab Scylla serrata from different regions of Tuticorin, Southeast Coast of India

The present study was performed to analyze the bioaccumulation of heavy metals, biochemical constituents, antioxidants, and metabolic enzymes in the crab Scylla serrata from different regions of Tuticorin, Southeast Coast of India. The study area consists of Threspuram and Harbour Beach which were polluted environments due to the discharge of industrial effluents and domestic sewage into them. Punnakayal, which is a low-polluted environment where the in-situ culture of S. serrata is carried out by local fish farmers, was selected as well. The results revealed that the level of heavy metals, biochemical constituents, antioxidants, and metabolic enzymes were significantly high in the crabs collected from Threspuram and Harbour Beach compared to the crabs collected from Punnakayal. This study indicates that crabs from polluted environments have significant heavy metals bioaccumulation which leads to elevated antioxidants and metabolic enzyme levels. This implies that the crabs are under oxidative and metabolic stress.

Genotoxic effects of tobacco use in residents of hilly areas and foot hills of Western Ghats, Southern India

Smoking and smokeless tobacco consumption is a significant risk factor that provokes genetic alterations. The present investigation was to evaluate the biomarkers of genotoxicity including micronucleus (MN), chromosome aberrations (CA) and DNA strand breaks among tobacco consumers and control individuals residing in hilly areas of Western Ghats, Tamilnadu, South India. This study included 268 tobacco consumers with equal number of controls. The tobacco consumers were divided into Group I (<10 years of tobacco consumption with an age range from 15 to 35 years) and group II (>10 years consumption above 35 years of age). Chromosome aberration (CA) and comet assay were performed using blood and micronucleus assay from exfoliated buccal epithelial cells obtained from tobacco consumers and controls. Elevated levels of CA were found in group II (Chromatid type: 2.39 ± 1.13 and chromosome type: 1.44 ± 1.24) exposed subjects, high micronucleus and DNA damage (TL:4.48 ± 1.24 and TM:3.40 ± 1.58) levels were significantly (p < 0.05) observed in both smoking and smokeless tobacco consumers when comparison with group I and controls. This study also observed a lack of awareness among the tobacco consumers about the harmful health effects of tobacco. Tobacco consumption contributes to the significant alteration in genetic materials. In addition, a high rate of spontaneous abortion was also seen in the studied population.

Utilization of marine fisheries wastes for the production of the freshwater fish Cyprinus carpio

The present study was aimed to assess the effects of complete replacement of fish meal with fisheries waste meals on survival, growth performance, digestive enzyme activities, and muscle compositions of the freshwater fish Cyprinus carpio. The proximate composition and mineral contents of three different fisheries wastes, such as Rastrelliger kanagurta, Sphyraena barracuda, and Fenneropenaeus indicus were analyzed. Based on the nutrient content of these fisheries waste, one control fish meal diet and three different complete fish meal replacement diets (diet 1, diet 2, and diet 3 formulated with R. kanagurta, S. barracuda, and F. indicus waste meals, respectively) were formulated. Fingerlings C. carpio were fed with these diets for a period of 6 weeks. Results from feeding experiments showed insignificant (p > 0.05) differences in survival, growth, and feed intake of C. carpio fed with control and three different fisheries waste diets. However, the digestive enzyme activity and muscle biochemical compositions were significantly (p < 0.05) altered in F. indicus waste meal fed C. carpio compared to other fisheries waste meal and control diets fed fish groups. Therefore, the present study suggests that R. kanagurta, S. barracuda, and F. indicus waste meals can be considered as alternative feed ingredients for fish meal to formulate low-cost feeds for C. carpio culture.