Comparison of the depletion of emamectin benzoate (SLICE®) residues from skeletal muscle and skin of Atlantic salmon (Salmo salar), for multiple dietary dose regimens at 10 °C

• Published in: Aquaculture 2011-05, Vol.315 (3), p.228-235
• Main Authors: Whyte, S.K., Westcott, J.D., Byrne, P., Hammell, K.L.
• Format: Article
• Language: English
• Subjects: Animal aquaculture; Animal productions; aquaculture tanks; Atlantic salmon; benzoates; Biological and medical sciences; Comparative analysis; Crustacea; Diet; double muscling; Emamectin benzoate; feeds; fillets; fish; fish feeding; Fundamental and applied biological sciences. Psychology; General aspects; Invertebrates; laboratory techniques; maximum residue limits; muscles; Musculoskeletal system; Residue depletion; Salmo salar; Salmon; Sea lice; seawater; skeletal muscle; Skin; Slice; Temperature; Tissues
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2011.02.043

The depletion of emamectin B 1a in the edible tissues of Atlantic salmon ( Salmo salar) was studied at two inclusion rates of emamectin benzoate (EMB; Slice®) in commercially prepared diets. Fish were maintained in tanks supplied by flow-through, temperature-controlled natural seawater at 10.08 ± 0.26 °C. Fish were administered a medicated diet containing a nominal dose rate of EMB at either, 50 μg kg −1 body weight day −1, the recommended manufacturer's dose, or 100 μg kg −1 body weight day −1 for seven consecutive days. Control fish received a non-medicated diet. Two trials were conducted; a single-only dose study where fish were fed 50 μg kg −1 body weight day −1 and a single–double dose comparison study, where fish were fed either 50 μg kg −1 body weight day −1 or 100 μg kg −1 body weight day −1. Laboratory tested EMB concentrations in the diet were 6.82 ± 0.13 mg g −1 of feed for the single-only trial and in the single–double comparison study, 7.6 ± 0.54 mg kg −1 of feed for the single dose and 15.2 ± 1.07 mg kg −1 of feed for the double dose. Individual variability in emamectin B 1a of muscle and skin tissues was high and considered related to hierarchal effects of feeding. Emamectin B 1a residues were determined in muscle fillet and skin samples at intervals from 1 to 45 days post-feeding in the single-only dose study and 1 to 20 days post-feeding in the single–double dose comparison study. Mean emamectin B 1a ranged from 60.5 to 7.3 ng g −1 in the muscle and 199.7 to 28.1 ng g −1 in the skin for the single-only study and in the single–double comparison study, 57.5 to 25.8 ng g −1 in the muscle of the single dose and 96.8 to 45.6 ng g −1 in the muscle of the double dose. Maximum residue levels allowed by Health Canada (CFIA) of 100 ng g −1 and 1000 ng g −1 were never detected in the muscle and skin, respectively, for the recommended dosage of 50 μg kg −1 whereas, 28.6% of fish receiving the double dose of 100 μg kg −1 were observed to have residue levels greater than 100 ng g −1 for muscle, ranging from day 1 through day 20 post-medication.