Fish meal replacement by plant and animal by-products in diets for the Australian short-finned eel, Anguilla australis australis (Richardson)

Abstract

In this experiment, 23% of fish meal protein was replaced with protein from Australian soybean meal (SBM), lupin meal (LM), corn gluten meal (CGM) and meat meal (MM) in nutritionally balanced experimental diets. Growth and growth efficiencies of juvenile Australian short-finned eel Anguilla australis australis (Richardson) elvers (2.23 ± 0.4-g average wet weight) were compared Elvers were fed twice a day to a total of 5% body weight per day for 63 days. Total weight gain (g), specific growth rate (% day-1), protein efficiency ratio (%) and productive protein value (%) were significantly higher (P < 0.05) for elvers fed the MM diet than for those fed the LM diet. There were no differences in diurnal ammonia-nitrogen excretion rates. However, diurnal urea-nitrogen excretion rates were significantly (P < 0.05) affected by diet and rates were two to three times higher for all diets, except CGM, 4 h following the afternoon feed. Diet significantly affected apparent digestibility (AD); ADs of protein for SBM and LM were significantly (P < 0.001) higher than for control diet, CGM and MM; AD of energy for LM was significantly (P < 0.05) lower than for all the other diets. Fish meal protein was replaced by CGM, SBM and MM without compromising growth rates of the Australian short-finned eel. However, whole lupin seed meal (LM) depressed growth and growth efficiencies most likely because of the high indigestible carbohydrate content. © 2005 Blackwell Publishing Ltd.