Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/30/2002
Publication Date: 1/1/2003
Citation: LOCHMANN, R., DAVIS JR, K.B., SIMCO, B. CORTISOL RESPONSE OF GOLDEN SHINERS NOTEMIGONUS CRYSOLEUCAS FED DIETS DIFFERING IN LIPID CONTENT. AQUACULTURE AMERICA CONFERENCE. 2003. p. 157. Interpretive Summary:
Technical Abstract: The golden shiner (Notemigonus crysoleucas) is the predominant fish species raised for bait for recreational fishing in the US. Baitfish are marketed as live products, and they undergo frequent handling during production and transport to distribution points. Nutritional enhancement of stress resistance is probably more important for baitfish than diets that maximize growth. The purpose of this study was to characterize the serum cortisol response in golden shiners under crowding stress, and to determine whether dietary lipid composition affects the cortisol response. Golden shiners were fed diets with 4 or 13% menhaden fish oil, or 4 or 13% poultry fat at 3% body weight for 4 weeks before the crowding stress. In a second experiment fish were fed diets with 10% lipid from cottonseed oil, cod liver oil, soybean oil, or soybean+cod liver oil for 6 weeks before the stress test. Serum cortisol was measured initially, two hours after the stressor was applied, and two hours after the stressor was removed. There were no differences in cortisol response of fish fed different diets in experiment 1. The overall pattern of the response was similar to that seen in other warmwater fishes. In experiment 2, initial and recovery cortisol levels were affected by diet. Fish fed a diet with equal amounts of SBO and CLO had reduced initial cortisol relative to fish fed the other diets. Two hours post-stress, fish fed the SBO+CLO diet had not recovered and had significantly higher cortisol than fish fed diets with either SBO or CLO alone. The main differences between the diets were the relative amounts and types of fatty acids of the n-3 and n-6 families. However, the mechanism by which dietary fatty acids affected the cortisol response is unknown.