The Correlation between Liver Dry Matter and Liver Lipid in Cultured Juvenile Red Drum Fed Various Diets

Abstract

Reared juvenile red drum Sciaenops ocellatus were used in a series of seven experiments and four trials testing the effects of 6 commercial and 15 experimental feeds on liver lipid content. Feed composition ranges (dry basis) were 49–62% protein, 5–18% lipid (including 0.5–14% fish oil), 7–18% ash, and 5–22% moisture. Temperature range was 15–32°C and salinity range 15–35‰. Fish weight was 0.4–1,582 g and total length 36–512 mm. Neither hepatosomatic index nor lipid droplet area (measured by image analysis) could be used to predict liver lipid content. However, a strong multiple correlation (R ² = 0.86) did exist between wet liver lipid (WLL) and liver dry matter (LDM), the regression being WLL = −57.325 + 8.1944(LDM) − 0.38069(LDM)² + 0.0076865(LDM)³ − 0.000052782(LDM)⁴. This result suggests that, in some cases, liver dry matter could be used to estimate liver lipid content for cultured red drum without the cost, labor, and hazardous chemicals associated with traditional solvent extraction methods.