Oxygen consumption and ammonia-N excretion of prawns (Penaeus chinensis) exposed to ambient ammonia

Abstract

Both oxygen consumption and ammonia-N excretion ofPenaeus chinensis had a negative power regression with body weight. WhenP. chinensis juveniles (0.079+-0.004 g) were subjected to increased ambient ammonia-N (un-ionized plus ionized ammonia as nitrogen) in the range of 0.015–5.529 mg/L at 25°C and pH 7.93–8.24, oxygen consumption (O2 mg/g/h) and ammonia-N excretion (mg/g/h) increased. Oxygen consumption and ammonia-N excretion of the shrimps exposed to control (0.015 mg/L) and 5.529 mg/L ammonia-N was 0.858 to 1.628, 1.159 to 2.675 O2 mg/g/h and 0.028 to 0.049 and 0.942 to 2.004 ammonia-N mg/g/h, respectively. Both oxygen consumption and ammonia-N excretion of the shrimp had a linear correlation after 6, 10, and 14 h; and had a power correlation after 20 h with ambient ammonia-N in the range of 0.015–5.529 mg/L. Mean cumulative amount of dissolved oxygen consumed in 20 h was 1.518, 1.786, 1.897, 2.085, 2.193, 2.322, and 2.526 mg; and a mean cumulative amount of excreted ammonia-N in 20 h was 0.059, 0.501, 0.671, 0.792, 1.527, 1.780, and 1.964 mg for individualP. chinensis exposed to 0.015, 0.618, 1.182, 2.112, 2.876, 4.381, and 5.529 mg/L ammonia-N, respectively.