PHYTOTOXICITY AND CHARACTERIZATION OF A LIQUID FERTILIZER PRODUCED BY LACTIC ACID FERMENTATION USING RAINBOW TROUT BY-PRODUCTS (Oncorhynchus mykiss)

Abstract

The increase of rainbow trout production in Peru generates a large amount of by-products which are not generally recycled, which generates greenhouse gases, eutrophication when they are thrown into the river and the appearance of pests when they are buried. The processes of hydrolysis and lactic acid fermentation allow to recover amino acids and nutrients, which can be used as a supplement for foliar fertilization of plants. The aim of this research was to develop a liquid fertilizer using rainbow trout by-products (FLVT), characterize it and evaluate the phytotoxicity. The total amino acid content was 3.2 g/100 g and protein content was 6.2 g/100 g. While the content of nitrogen, phosphorus and potassium were 12 040 mg/l, 1 189 mg/l, 5 540 mg/l, respectively. The liquid fertilizer did not contain E. coli or Salmonella sp. While the content of heavy metals such as lead, cadmium and chromium were lower than the maximum permissible limits according to the regulations for liquid fertilizers. In the phytotoxicity test on Lactuca sativa lettuce seeds, the concentrations of FLVT from 0.1% to 0.001% were free of phytotoxic substances and germination index values (IG) were greater than 80%.