Metabolism, health and fillet nutritional quality in Atlantic salmon (Salmo salar) fed diets containing n-3-rich microalgae.
Microalgae, as primary producers of EPA and DHA, are among the most prominent alternative sources to fish oil for n-3 long-chain PUFA in animal and human nutrition. The present study aimed to assess technical, nutritional and fish health aspects of producing n-3-rich Atlantic salmon (Salmo salar) fish fillets by dietary supplementation of increasing levels of a DHA-producing Schizochytrium sp. and reduced or without use of supplemental fish oil. Atlantic salmon smolt were fed diets with graded levels of microalgae for 12 weeks, during which all fish showed high feed intake rates with postprandial plasma leptin levels inversely correlating with final mean fish body weights. Fish performance was optimal in all experimental treatments (thermal growth coefficient about 4·0 and feed conversion ratio 0·8-0·9), protein digestibility was equal in all diets, whereas dietary lipid digestibility inversely correlated with the dietary levels of the SFA 16 : 0. Fillet quality was good and similar to the control in all treatments in terms of n-3 long-chain PUFA content, gaping, texture and liquid losses during thawing. Histological fluorescence staining and immunofluorescence analysis of salmon intestines (midgut: base of intestine and villi) revealed significant effects on slime, goblet cell production and inducible nitric oxide synthase (iNOS) activity with increasing levels of dietary Schizochytrium sp. supplementation. Microarray analysis did not reveal any signs of toxicity, stress, inflammation or any other negative effects from Schizochytrium sp. supplementation in diets for Atlantic salmon.
Nofima AS , Department of Nutrition and Feed Technology , N-5141 Fyllingsdalen , Norway.
Katerina
K
Kousoulaki
Nofima AS , Department of Nutrition and Feed Technology , N-5141 Fyllingsdalen , Norway.
Tone-Kari Knutsdatter
TK
Østbye
Nofima AS , Department of Nutrition and Feed Technology , N-5141 Fyllingsdalen , Norway.
Aleksei
A
Krasnov
Nofima AS , Department of Nutrition and Feed Technology , N-5141 Fyllingsdalen , Norway.
Jacob Seilø
JS
Torgersen
Nofima AS , Department of Nutrition and Feed Technology , N-5141 Fyllingsdalen , Norway.
Turid
T
Mørkøre
Alltech Inc. , Sarney , Dunboyne , County Meath , Republic of Ireland.
John
J
Sweetman
0_ScYE, 0 g/kg Scizochytrium sp. + yeast extract (control); 15_ScYE, 150 g/kg Scizochytrium sp. + yeast extract; 1_ScYE, 10 g/kg Scizochytrium sp. + yeast extract; 6_ScYE, 60 g/kg Scizochytrium sp. + yeast extract; ADC, apparent digestibility coefficient; CK, creatine kinase; FAME, fatty acid methyl esters; FCR, feed conversion ratio; Farmed salmon fish fillet nutritional quality; ISO, International Organization for Standardization; Microalgae; ScYE, Scizochytrium sp. + yeast extract; TGC, thermal growth coefficient; iNOS, inducible nitric oxide synthase; n-3 LC-PUFA, n-3 long-chain PUFA; n-3 Long-chain PUFA