PPARa, PPARb and SREBP 1 were also regulated in response to genotype, being down regulated in Lean fish, but only when fed the VO diet. In cobia, Rachycentron canadum, a negative correlation was found between PPARa mRNA levels in liver and body lipid deposition. Furthermore, PPARb appears to play a similar role in fish to that in mammals, as a ubiquitous regulator of fat burning and with a role in energy mobilisation during early development. Therefore, both Inhibitors,Modulators,Libraries PPARa and PPARb might have a role in the control of adipogenesis in fish and it may be the case that, similarly to chickens, Fat salmon might have higher lipid turnover than their Lean counterparts when fed a diet that predisposes for hepatic fat deposition, even though the end result is higher lipid accumulation in liver.

To explain this, Collin et al. suggested that a fat chicken family is better equipped to deal with higher circulating levels Inhibitors,Modulators,Libraries of TAG when fed a high fat diet, compared to lean chicken. On the other hand, we observed a direct relationship between SREBP 1 and FAS expression in the Fat family group in response to diet, as well as in VO fed fish in response to genotype. It thus appears that SREBP 1 may be partly responsible for higher lipogenesis in Fat fish, compared to Lean, when fed VO. Conclusions This study has enabled the identification of metabolic pathways and key regulators that may respond differently to more sustainable diets, in which FO is replaced by VO, depending on genotype, thus confirming the potential of microarrays as hypothesis generating tools, even in these nutritional studies where changes in gene expression are quite subtle.

Collectively, and in conjunction with previous studies, the data indicate that dietary lipid composition may potentially affect glucose, glycogen storage and inter mediary metabolism, in addition Carfilzomib to lipogenesis, supporting a role for LC PUFA in fuel partitioning in fish as well as in mammals. Therefore, more integrative studies investi gating the effects of dietary VO on energy homeostasis are required. However, important genotype related differences may also exist in the regulation of metabolism. In terms of lipid metabolism, expression of LC PUFA and lipid bio synthesis genes, as well as of key regulator transcriptional Inhibitors,Modulators,Libraries factors, was differentially affected by diet depending on the genetic background of the fish.

Although further studies are required, the present data indicate that it will be possi ble to identify families better adapted to alternative diet formulations that might be appropriate for future genetic selection programmes. Methods Feeding trial and sampling Inhibitors,Modulators,Libraries A dietary trial was conducted using two genetically char acterised and contrasting groups of farmed Atlantic sal mon post smolts, comprising full sib families selected from the Landcatch Natural Selection Ltd breed ing program.