Analysis of copper bioconcentration in the gills of Pacific white shrimp (Litopenaeus vannamei) Daniela Oliveira Teixeira de Sousa, Rodrigo Schveitzer, Helen Sadauskas-Henrique

Abstract

 The Pacific White Shrimp, Litopenaeus vannamei, holds significant importance in the field of shrimp farming. Even in systems with limited water exchange, there is an accumulation of and toxicity from metals, such as copper, present in the feed. Given that L. vannamei can be cultivated across a range of salinities, this present study sought to evaluate how varying salinities can influence copper toxicity (LC50-24 h) and copper bioaccumulation in the gills of L. vannamei postlarvae (PLs). PLs were acclimated to three different salinities (5, 15, and 30 ppt) for 24 hours. Subsequently, they were exposed for 24 hours to different nominal copper concentrations at 5 ppt (0.05 to 0.8 mg/l), 15 ppt (3.5 to 100 mg/l), and 30 ppt (2 to 144 mg/l) for the calculation of LC50-24 h. Afterward, PLs were exposed to 100% of the LC50-24 h value at each salinity for 24 hours to analyze the copper concentration in the gills. Copper toxicity was strongly influenced by salinity, with higher LC50-24 h values observed at lower salinities. In animals acclimated to 30 ppt, the LC50-24 h was 106.82 mg/l (lower limit: 84.87 mg/l, upper limit: 134.45 mg/l). In contrast, in animals acclimated to 15 and 5 ppt, the LC50-24 h was 49.21 mg/l (lower limit: 35.53 mg/l, upper limit: 68.17 mg/l) and 0.30 mg/l (lower limit: 0.23 mg/l, upper limit: 0.40 mg/l), respectively. However, copper bioconcentration was higher in the gills of PLs at 30 ppt (0.12 mg/kg). Therefore, metal accumulation via feed in systems with low or no water exchange at reduced salinities can lead to increased mortality of L. vannamei due to elevated copper toxicity. Nevertheless, this toxicity seems not to be related with the Copper bioacumulation in the gills, once higher copper bioaccumulation was observed in PLs at 30 ppt..