Project description:Background: Commercial Atlantic salmon is fed diets with high fat levels to promote fast and cost-eﬀective growth. To avoid negative impact of obesity, food additives that stimulate fat metabolism and immune function are of high interest. TTA, tetradecylthioacetic acid, is a synthetic fatty acid that stimulates mitochondrial β -oxidation most likely by activation of peroxysome proliferator-activated receptors (PPARs). PPARs are important transcription factors regulating multiple functions including fat metabolism and immune responses. Atlantic salmon experiments have shown that TTA supplemented diets signiﬁcantly reduce mortality during natural outbreaks of viral diseases, suggesting a modulatory role of the immune system. Results: To gain new insights into TTA eﬀects on the Atlantic salmon immune system, a factorial, high-throughput microarray experiment was conducted using a 44K oligo nucleotide salmon microarray SIQ2.0 and the Atlantic salmon macrophage-like cell line ASK. The experiment was used to determine the transcriptional eﬀects of TTA, the eﬀects of TTA in poly(I:C) elicited cells and the eﬀects of pretreating the cells with TTA. The expression patterns revealed that a large proportion of genes regulated by TTA were related to lipid metabolism and increased mitochondrial β -oxidation. In addition we found that for a subset of genes TTA antagonized the transcriptional eﬀects of poly(I:C). This, together with the results from qRT-PCR showing an increased transcription of anti-inﬂammatory IL10 by TTA, indicates anti-inﬂammatory eﬀects. Conclusions: We demonstrate that TTA has signiﬁcant eﬀects on macrophage-like salmon cells that are challenged by the artiﬁcial dsRNA poly(I:C). The immune stimulatory eﬀect of TTA in macrophages involves increased lipid metabolism and suppressed inﬂammatory status. Thus, suggesting that TTA directs the macrophage-like cells towards alternative, anti-inﬂammatory, activation. This has positive implications for TTA as a feed additive.

Project description:Background: Commercial Atlantic salmon is fed diets with high fat levels to promote fast and cost-eﬀective growth. To avoid negative impact of obesity, food additives that stimulate fat metabolism and immune function are of high interest. TTA, tetradecylthioacetic acid, is a synthetic fatty acid that stimulates mitochondrial β -oxidation most likely by activation of peroxysome proliferator-activated receptors (PPARs). PPARs are important transcription factors regulating multiple functions including fat metabolism and immune responses. Atlantic salmon experiments have shown that TTA supplemented diets signiﬁcantly reduce mortality during natural outbreaks of viral diseases, suggesting a modulatory role of the immune system. Results: To gain new insights into TTA eﬀects on the Atlantic salmon immune system, a factorial, high-throughput microarray experiment was conducted using a 44K oligo nucleotide salmon microarray SIQ2.0 and the Atlantic salmon macrophage-like cell line ASK. The experiment was used to determine the transcriptional eﬀects of TTA, the eﬀects of TTA in poly(I:C) elicited cells and the eﬀects of pretreating the cells with TTA. The expression patterns revealed that a large proportion of genes regulated by TTA were related to lipid metabolism and increased mitochondrial β -oxidation. In addition we found that for a subset of genes TTA antagonized the transcriptional eﬀects of poly(I:C). This, together with the results from qRT-PCR showing an increased transcription of anti-inﬂammatory IL10 by TTA, indicates anti-inﬂammatory eﬀects. Conclusions: We demonstrate that TTA has signiﬁcant eﬀects on macrophage-like salmon cells that are challenged by the artiﬁcial dsRNA poly(I:C). The immune stimulatory eﬀect of TTA in macrophages involves increased lipid metabolism and suppressed inﬂammatory status. Thus, suggesting that TTA directs the macrophage-like cells towards alternative, anti-inﬂammatory, activation. This has positive implications for TTA as a feed additive. Factorial designed experiment: factor pretreatment = 2 levels (Control, TTA); factor treatment = 4 levels (Control, TTA, polyIC, TTA+polyIC). Experiment was performed with 2 biological replicates (different passages). 1 array hybridization failed and was excluded from the dataset. Therefore total number of arrays =15

Project description:Current commercially available feeds for salmon are predominantly made of plant ingredients, with consequent changes to the composition and contents of a range of nutrients and other components in the diet. There are concerns that, with these major changes in raw materials, new feeds will affect not only the composition and contents of nutrients, but also the bioavailability and, combined with the limited knowledge of micronutrient requirements for Atlantic salmon, this might impact growth performance and health of the fish. The present study investigated the effects of graded levels of a micronutrient package supplemented to feeds formulated with low levels of marine ingredients and fed to diploid and triploid Atlantic salmon throughout the freshwater phase. Specifically, fish were fed three diets containing low levels of FM and FO and identical in formulation other than being supplemented with 3 levels (L1, 100 %; L2, 200 % and L3, 400 %) of a micronutrient mix formulated as a modification of current nutrient levels reported for salmon. Duplicate groups of diploid and triploid parr were fed the experimental diets from around 30 g to seawater transfer and the effects on growth performance, feed efficiency, biochemical composition, liver histology, hepatic gene expression (transcriptome) and smoltification efficiency determined. Microarray analysis revealed that the hepatic transcriptome profile of diploid fish fed diet L2 was more similar to that observed in triploids fed diet L3 than to those fed L2, suggesting that micronutrient requirements of triploid salmon may differ from levels accepted in diploid salmon. Different levels of micronutrient supplementation affected the expression of key genes involved in lipid metabolism. In particular sterol biosynthesis pathways (steroid and terpenoid backbone synthesis) were down-regulated in both L2-fed diploids and L3-fed triploids when compared with diet L1-fed diploids and triploids, respectively. Gene sets analysis showed an up-regulation of genes involved in immune processes in triploid salmon fed diet L3. Another biological category affected by diet in triploid salmon was genetic information processing. In fish fed diet L3 down-regulation of RNA degradation, proteasome, RNA polymerase, spliceosome and ribosome was observed, suggesting a decrease in protein turnover in this group, which may indicate a decrease in energy expenditure. In addition, one-carbon metabolism was affected by diet in diploid and triploid salmon.

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Tetradecylthioacetic acid effect on heart ventricle

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