Dietary toxicity of manganese to shrimp and its accumulation in bioflocs.

Kuhn, D.D.; Lawrence, A.L.; Crockett, J.

Bioflocs were produced in pilot-scale biological reactors using acetate, glycerine or sugar as a carbon supplement while treating fish-effluent waters. Bioflocs were dried and evaluated for nutritional quality and ingredient suitability. It was discovered that all bioflocs had excess manganese levels (9,500 mg kg-1). Two trials were conducted as follows: (i) first feeding trial was a 6-week experiment to determine the dietary toxicity of manganese to shrimp ( Litopenaeus vannamei) in diets without bioflocs, and (ii) the second feeding trial (5 weeks) was conducted with the aforementioned bioflocs with elevated manganese content. In first feeding trial, experimental diets contained increasing concentrations of manganese: 260, 570, 1,100, 2,300, and 3,500 mg kg-1. Levels of manganese above 570 mg kg-1 significantly ( p -1. In second feeding trial, experimental diets contained the different sources of bioflocs: acetate biofloc 100 g kg-1, glycerine biofloc 100 g kg-1, sucrose biofloc 100 g kg-1 replacing soybean meal and acetate biofloc 100 g kg-1- FM (replaced fishmeal). Compared to the control, the glycerine biofloc 100 g kg-1 and acetate biofloc 100 g kg-1- FM significantly ( p < .05) suppressed shrimp growth. The findings in this article demonstrate that careful considerations are needed in regard to potential elevated levels of trace elements in biofloc.

WHITELEG shrimp; MANGANESE; BIOACCUMULATION in fishes; DIETARY supplements; FISH feeds; FISH growth

Aquaculture Nutrition, 2017, Vol 23, Issue 5, p1121

1353-5773

Academic Journal

10.1111/anu.12480