Submitted to: North American Journal of Aquaculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/30/2006
Publication Date: 6/11/2007
Citation: Li, M.H., Robinson, E.H., Oberle, D.F., Bosworth, B.G. 2007. Proximate Composition and Collagen Concentration of Processing Residue of Channel Catfish. North American Journal of Aquaculture. 69:311-213. Interpretive Summary: By-products from processing of farm-raised catfish (skin, head, frames, viscera, and trimmings) are typically made into catfish meal and catfish oil for use in animal feeds. However, there may be other, more profitable uses for some of these by-products. The percentage of these by-products relative to whole weight, and the crude protein, fat, moisture, and collagen concentration of each by-product was determined. For market-weight catfish, by-products accounted for 56.8% of whole weight: head 24%, frame 13.6%, viscera 10.8%, skin 4.7% and trimmings (fins etc.) 3.7%. The skin had the highest protein (19.9% of wet tissue weight) and collagen (14.2% of wet weight). The viscera had the highest level of fat (32.7% of wet weight). The head had the highest ash concentration (6.9% of wet weight). Catfish skin has a high concentration of collagen and collagen production may be a profitable alternative use of catfish skin.
Technical Abstract: Residues (including heads, skin, viscera, frames, and trimmings) from the channel catfish Ictalurus punctatus processing industry have generally been made into catfish meal and catfish oil that are used in animal feeds. There may be more efficient uses for these materials, such as producing collagen and other products. A study was conducted to determine the percentages of each component of the processing residue relative to whole fish weight and their crude protein, crude fat, moisture, ash, and collagen concentrations. Of a market-size channel catfish, the head accounted for 24% of the whole weight, the frame 13.6%, the viscera 10.8%, the skin 4.7%, and the trimmings 3.7%. These processing residues represent a total of 56.8% of the total fish weight. The highest crude protein and collagen concentrations were found in the skin (protein, 19.9% of wet tissue and 82.1% of dry matter; collagen, 14.2% of wet tissue and 58.7% of dry matter). The viscera had the highest fat level (32.7% of wet tissue and 69.6% of dry matter). The head remnants had the highest ash concentration (6.9% of wet tissue and 19.9% of dry matter). The skin had a high collagen concentration and is therefore a good candidate for collagen production.