[Preparation of microbial silage from fish of underutilized species]

Fish silage was produced by microbial means from a mixture of several fish species which are not used for human consumption, and form part of the shrimp by-catch. The fish was mixed with a carbohydrate source (molasses) and a starter culture of Lactobacillus plantarum 8014. The mixture was fermented at 30 +/- 2 degrees C. Several tests were undertaken to determine the optimal conditions and concentration of molasses (5, 10 and 15%) and Lactobacillus (0.5, 1.0, 2.5, 5.0 and 10.0%). Results indicated that 1% of microorganisms and 15% of molasses were the optimal proportions to produce a stable fish silage. The production process and stability study of fish silage were followed through chemical, physical and microbiological tests. As findings revealed, the first six days of the process are related to acid production, pH reduction and microbial control, while after this period the process is basically related to protein hydrolysis. In addition, sensory tests of flavor and color were performed. The results of this study suggest the feasibility of utilizing this marine resource at present discarded, through a technological scheme, to produce fish silage for animal feed.