Effects of Dietary Lipid Concentration, a Dairy–Yeast Prebiotic, and Fish and Nonfish Protein Sources on Growth, Survival, and Nonspecific Immune Response of Golden Shiners in Indoor Tanks and Outdoor Pools
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We conducted two feeding trials in which golden shiners Notemigonus crysoleucas were given six practical diets: two basal diets with 5% fish meal and either 4% or 10% supplemental lipid (poultry fat [PF]); two prebiotic diets with 2% dairy-yeast prebiotic, 5% fish meal, and 4% or 10% PF; and two 4% or 10% PF diets that contained no fish meal or prebiotic. To compare diet effects in the presence or absence of natural foods, one trial was conducted in indoor aquaria and one was conducted in outdoor pools. Diet effects were assessed by measuring growth, survival, feed efficiency, and body composition in both trials and Fulton's condition factor K in the outdoor pool trial. A subset of fish from the outdoor trial was grown to a larger size for analysis of alternative complement activity (ACH50). The prebiotic enhanced growth and feed conversion ratio (FCR) slightly in the indoor aquarium trial. Weight gain and FCR did not differ among diet groups in the outdoor trial, reflecting the influence of natural foods. Survival in aquaria was higher in fish fed the 10% PF diets than in fish given the 4% PF diets. The prebiotic slightly reduced survival in outdoor pools, but survival was 96% or higher for all diet groups. The K-value was higher in fish that were given 10% PF diets than in fish fed 4% PF diets. Whole-body proximate composition was similar among treatment groups for the aquarium trial. In the outdoor trial, whole-body lipid was higher in fish fed the diets with 10% PF versus those fed diets with 4% PF, and dry matter followed a similar pattern. The ACH50 was similar between golden shiners that were fed diets with the prebiotic and those given diets without the prebiotic. Fish meal did not enhance any of the performance criteria in golden shiners held in tanks or pools. Although prebiotic addition and lipid concentration significantly affected several aspects of fish performance and body composition, some of the differences were numerically small. Economic analysis should be conducted to determine whether addition of a prebiotic or extra lipid to commercial diets is justified for production and distribution of golden shiners. © Copyright by the American Fisheries Society 2009.
author list (cited authors)
Lochmann, R. T., Sink, T. D., & Phillips, H.