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The suitability of land animal by-products (ABPs) in feed for Atlantic salmon postsmolts (initial weight 372 g) in sea water was studied in a feeding experiment, using poultry by-product meal (PBM) and porcine blood meal (BM) as protein sources and poultry oil as fat source. Four extruded feeds were tested in a 2 * 2 factorial model, with or without ABP protein sources and with or without poultry oil. The control feed contained a mix of marine and plant ingredients. Initial feed intake was highest in the ABP protein-based diets, whereas poultry oil had a weak opposite effect. No differences were seen in growth rate or body weight. Addition of PBM and BM led to increased FCR, and lower retention of crude protein and energy. This could be explained by lower digestibility of amino acids and crude protein, and a slightly lower energy level in these diets. Reduced igf1 mRNA levels in liver and muscle were seen in fish fed dietary ABP protein and oil. Despite lower protein digestibility of ABP protein, this study confirms the suitability of ABP protein and lipid in combination with plant ingredients in feed for Atlantic salmon growers. [ABSTRACT FROM AUTHOR]

Residue levels of the antibacterials enrofloxacin and ciprofloxacin were analysed in 15 commercially relevant animal by-products ( ABPs). Enrofloxacin was detected in all ABPs, and ciprofloxacin was detected in 11 of 15 ABP samples. Feed to muscle and skin carry -over of low background enro- and ciprofloxacin levels were assessed by applying a simple toxicokinetic model. The muscle and skin uptake and elimination rates were established in Atlantic salmon ( Salmo salar L.) fed enrofloxacin enriched diets (100 μg kg−1 'low' and 4000 μg kg−1 'high') in triplicate for 41 days followed by a 90 days depuration period. The terminal half-lives were 17 ± 0.4 and 18 ± 0.7 days, and uptake rates were 9.3 ± 3.3 and 11 ± 3.1 (day−1) for the 'low' and 'high' groups, respectively. Only fish fed high background levels had quantifiable levels of the metabolite ciprofloxacin with a formation of 0.25 ± 0.01% day−1. The toxicokinetic carry-over model predicted muscle and skin steady state levels of 1.8 μg kg−1 when fed theoretically high enrofloxacin levels (158 μg kg−1), which is below the EU limit of 100 μg kg−1 for enrofloxacin in finfish food products. The antibacterial residue levels could however be detected in EU food surveillance programmes. [ABSTRACT FROM AUTHOR]

Plant ingredients and processed animal proteins are alternative feedstuffs for fish feeds in aquaculture. However, their use can introduce contaminants like pesticides that are not previously associated with marine Atlantic salmon and gilthead sea bream farming. This study covers the screening of around 800 pesticides by gas chromatography (GC) and liquid chromatography (LC) coupled to high resolution time-of-flight mass spectrometry in matrices throughout the entire marine food production chain. Prior to analysis of real-world samples, the screening methodology was validated for 252 pesticides to establish the screening detection limit. This was 0.01 mg kg −1 for 113 pesticides (45%), 0.05 mg kg −1 for 73 pesticides (29%) and >0.05 mg kg −1 for 66 pesticides (26%). After that, a quantitative methodology based on GC coupled to tandem mass spectrometry with atmospheric pressure chemical ionization source (GC-APCI-MS/MS) was optimized for the pesticides found in the screening. Although several polar pesticides, of which pirimiphos methyl and chlorpyriphos-methyl were most dominant, were found in plant material and feeds based on these ingredients, none of them were observed in fillets of Atlantic salmon and gilthead sea bream fed on these feeds. [ABSTRACT FROM AUTHOR]