89B-7 |
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A. M. MARTIN and A. Bezerra. Dept. of Biochemistry, Memorial Univ. of Newfoundland, 300 Prince Philip Dr., Saint John's, NF A1B 3X9, Canada Tilapia, Oreochromis niloticus is a fish species cultivated in tropical regions. In those areas where it is processed, there are economic and environmental needs for the complete utilization of the biomass caught. Ensiling is a potential simple and inexpensive means of recovering the wastes from the fisheries processing operations. The objective of this work was to study the chemical composition of the silage produced by fermentation of tilapia as a way to evaluate its potential incorporation in feed products. Tilapia silage was produced by the inoculation of lactic acid bacteria to a mixture of 6 parts of tilapia wastes to one part sugar cane molasses, required as a carbon and energy source for the fermentation process. To prevent microbial contamination, potassium sorbate was added to the medium. A series of laboratory scale batch experiments were conducted at 30oC, with an initial pH of 5.8. Determinations of ash, lipid, moisture and protein contents were conducted on the final product, utilizing standard procedures, and compared with those of commercial fishmeal. The results showed that at 14 days the lactic acid ensiling process had stabilized at a pH of 4. The chemical composition of the silage produced was approximately (on a dry matter basis) of 41% protein, 13% lipids, and 15% ash. The balance (31%) consisted of a nitrogen-free extract containing carbohydrates, a relatively high fraction which could be explained by the use of molasses. As a consequence, the silage protein content was 26% less than that present in fishmeal. However, the protein content of the silage was still fairly high, and adequate to be incorporated in feed formulations. It can be concluded that, based on its chemical composition, lactic acid tilapia silage could be a potential protein source in feed production. This use will also reduce pollution problems caused by fish wastes.
Session 89B, Aquatic Food Products: Surimi, gels and by-products
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |