Processes for Improving the Quality of Whitefish Meal

Abstract

White fish meals made from fishery processing wastes were modified by screening dried carcass waste prior to grinding it into meal, or by mechanically deboning prior to processing into fish meal. Screening the dried carcass waste reduced the ash content and increased the fat and protein contents of the resulting fish meal compared to not screening. By mechanically deboning the carcass waste prior to meal processing, the ash content of the resulting meal was further reduced and the protein and fat contents increased to levels comparable to those of high-quality herring meal. The modified meals were used to replace herring meal in feeds for juvenile chinook salmon. After eight weeks of feeding, no significant differences were seen in the average weights of the fish or in feed efficiency ratios, indicating that the nutritional value and palatability of the three diets were equivalent. The results show that low-ash alternatives to herring meal in salmon feeds can be produced from high-ash fish processing waste.