Introduction
Feed represents approximately 80% of the environmental footprint of aquaculture farming. Europe relies heavily on imported proteins to supply over 70% of the protein required for feed formulation for livestock and aquaculture (the Protein Gap). Soybean meal forms the major proportion of this imported protein meal and the challenge for the European feed industry is to source a locally produced protein meal that can replace soybean meal in ration formulation. Corn Fermented Protein (CFP) is a Super (>50% crude protein content) corn protein product which is produced by mechanical separation of the whole stillage fractio n from the dry grind production process used to produce bioethanol a renewable transport fuel that reduces GHG emissions by 72% and fosters rural development. Produced as a co-product in the production of a renewable fuel, the carbon index of CFP is approximately one tenth of the production of an equivalent soybean meal protein product. During the 50-60h fermentation of starch to produce ethanol a large quantity of yeast is generated, approximately 8% of the grain starch is used in the generation of yeast. The yeast generated in the process passes through distillation and in the whole stillage remains as yeast cell wall material. Corn fermented protein contains 25% yeast cell wall material of which 44% is protein in the dry matter, derived from a fermentation process. The yeast cell mannans and glucans when used in the rearing period help improve innate and adaptive immunity. CFP is an alternative protein with bioactive components. There are many claims for the benefits of fermentation in terms of imp roved digestibility and mineral availability of plant material. The feed industry requires concrete evidence of efficacy before it adopts a new product. Over 50 published trials have been completed to demonstrate how to formulate feeds using CFP as a replacement of a wide range of currently used protein supplements in diets for all classes of livestock and companion animals. A major part of this program has been to evaluate the use of CFP in aquaculture species and this presentation summarises the data generated in th ese trials.
Results
Digestibility trials (stripping collection methodology) were carried out with Rainbow Trout (Oncorhynchus mykiss), average weight 250g . Average of 5 separate trials . Ingredient apparent digestibility coefficients of each nutrient in the test diet and ingredients were calculated using the traditional formulas presented in Kleiber (1961) and Forster (1999) (Table1).
The digestibility of the protein is approximately 88% measured in salmon and trout. Growth trials have been completed with salmon, trout, tilapia, shrimp and juvenile channel catfish summarised in Table 2.
Discussion and Conclusions
The data indicates that CFP is an excellent alternative protein and can replace a range of currently employed protein materials for use in diets for a range of commercially important aquaculture species. There are three unique characteristics of the product that merit note. Corn fermented protein is the product of a 50-60h fermentation process which increases the digestibility of protein and availability of phosphorus. The yeast component of CFP provides additional health benefits and since the product is a co-product of the generation of renewable fuel, CFP has a uniquely low Carbon Index valuable in European formulations.