Apparent digestibility of canthaxanthin in rainbow trout: effect of dietary fat level, antibiotics and number of pyloric caeca

Abstract

Apparent digestibility coefficients (ADC) of lipid and canthaxanthin were studied in twelve rainbow trout families with 45 to 89 pyloric caeca, fed four experimental diets containing the same level (130 mg/kg) of synthetic canthaxanthin. Diets differed in lipid content (lipid-poor, 4%; lipid-rich, 15%) and by antibiotic supplementation (a combination of Flumequine 0.8 g/kg and Gentamycin 3.45 g/kg). The test families and their number of pyloric caeca did not induce any significant variation in the lipid or canthaxanthin ADC. Lipid ADC was significantly higher for the lipid-rich, antibiotic-supplemented diet (94.4%) than for the other diets (from 89.6% to 91.4%). Canthaxanthin ADC was significantly higher for the lipid-rich diets (64.3% without antibiotics, 54.1% with antibiotics) than for the lipid-poor diets (35.8% without antibiotics, 38.7% with antibiotics).