Effect of the arachidonic acid/vitamin E interaction on the immune response of juvenile Atlantic salmon (Salmo salar) challenged againstPiscirickettsia salmonis

Abstract

Atlantic salmon (Salmo salar) were fed 6 experimental diets containing three levels of arachidonic acid (ARA) (0.18 g kg−1, 0.28 g kg−1 and 0.63 g kg−1 for low, medium and high levels, respectively) and two levels of vitamin E (150 and 730 mg kg−1 for low and high levels, respectively). At the end of the experimental period, fatty acids in the liver and immunity markers (lysozyme activity, respiratory burst and phagocytic activity) were determined and fish subjected to a challenge test against the salmonid rickettsial syndrome (SRS) pathogen. ARA, vitamin E or their interaction did not exert an effect on fish performance, whereas ARA alone clearly increased the deposition of ARA. Dietary vitamin E only enhanced liver vitamin E deposition, while the interaction of ARA and vitamin E influenced lysozyme activity and EPA/ARA ratio pointing out the effect of both nutrients on the fish immune system and metabolism. Only the medium concentration contributed to reducing mortality when the fish were exposed to the SRS pathogen. In conclusion, different levels of supplementation with ARA and vitamin E in the diet had no effect on productivity, but did have effects on immune markers and cumulative mortality when fish were exposed to the SRS pathogen.

Dietary Supplementation With ω6 LC-PUFA-Rich Algae Modulates Zebrafish Immune Function and Improves Resistance to Streptococcal Infection

“…An increase in lysozyme activity, along with enhanced survival, was recorded in our earlier study with guppy fry that were fed with artemia enriched in WT L. incisa ( 14 ). Furthermore, enhanced lysozyme activity with ARA-suplemented diets is documented in recent studies on rabbitfish, Atlantic salmon and grass carp ( 15 , 31 , 45 ). Lysozyme activity is an important index of innate imunity in fish and is well recognized as a useful indicator of fish health ( 46 ).…”

Supplementation of arachidonic acid rich oil in European sea bass juveniles (Dicentrarchus labrax) diets: effects on growth performance, tissue fatty acid profile and lipid metabolism

“…Ash content was determined by combustion at 600ºC for 12h. Fatty acid methyl esters profiles were prepared by transmethylation (Christie 2003) and separated by gas chromatography (GC-14A, Shimadzu, Japan) following the conditions described by Izquierdo et al (1992). Fatty acid methyl esters quantification was performed by a flame ionizator detector and identification by comparison with external and well-characterized fish oils standards (EPA 28, Nippai, Ltd Tokyo, Japan).…”

Immune-enhancing effects of anionic macromolecules extracted from Codium fragile coupled with arachidonic acid in RAW264.7 cells

“…Activated macrophages secrete cytokines such as TNF-α, IL-1β and IL-6 [ 37 – 39 ] to defend against intracellular pathogens [ 40 ]. Normally, n-6 fatty acid plays an important role in pro-inflammatory processes by stimulating the production of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) [ 16 , 17 , 41 ]. The current results showed that most of the immune-associated genes were significantly enhanced with the supplementation of ARA, compared to treatment of Codium alone ( Fig 3 ), suggesting that ARA helped Codium to increase the expression of immune-associated genes in RAW264.7 cells.…”

“…Fatty acids are classified as saturated, monounsaturated, or polyunsaturated fatty acids (PUFA) by their degree of saturation. PUFAs such as dihomo-gamma-linolenic acid (DGLA), arachidonic acid (ARA, 20:4n-6) and eicosapentaenoic acid (EPA, 20:5n-3) are the precursors of eicosanoids which include prostaglandins (PG), thromboxanes (TX), lipoxins (LX), and leukotrienes (LT) [16,17]. These compounds are associated with the host defense system against infections including resistance to stress stimuli, the immune response, and inflammatory processes [17].…”

“…PUFAs such as dihomo-gamma-linolenic acid (DGLA), arachidonic acid (ARA, 20:4n-6) and eicosapentaenoic acid (EPA, 20:5n-3) are the precursors of eicosanoids which include prostaglandins (PG), thromboxanes (TX), lipoxins (LX), and leukotrienes (LT) [ 16 , 17 ]. These compounds are associated with the host defense system against infections including resistance to stress stimuli, the immune response, and inflammatory processes [ 17 ]. Normally, ARA plays an important role in inflammatory processes and stimulates the production of pro-inflammatory cytokines [ 18 ], whereas EPA plays a key role in the anti-inflammatory process [ 19 – 21 ].…”