AN ASSESSMENT OF ENSILING THE PROCESSING WASTES FROM DOGFISH TO PRODUCE A PROTEIN FEED FOR MONOGASTRIC ANIMALS

Dogfish (Squalus acanthias) processing wastes were readily hydrolyzed in the presence of 1.5% formic acid to produce a stable, liquid product free of bones and scales. The rate and the extent of solubilization is temperature dependent. A temperature of 45 °C provided a maximum digestion without denaturing the hydrolytic enzymes present in the fish silage. The resultant acidified product was stable at ambient temperature for 6 mo. The dogfish silage contained 74.4% moisture, 3.0% nitrogen, and 3.4% ash. In a protein evaluation trial with rats the true digestibility of the nitrogen fraction of the silage was estimated to be 93.5%. However, when fed alone, the biological value of the silage was low and was not appreciably improved by the addition of lysine or methionine. It was concluded from this pilot study that waste from the processing of dogfish could be successfully made into fish silage but that the end product would need to be combined with amino acids or other protein concentrates for it to be of va...