Characterization of the fatty acyl elongase (elovl) gene family, and hepatic elovl and delta-6 fatty acyl desaturase transcript expression and fatty acid responses to diets containing camelina oil in Atlantic cod (Gadus morhua).

For aquaculture to become sustainable, there is a need to substitute fish oil [FO, rich in ω3 long chain polyunsaturated fatty acids (LC-PUFA) such as 20:5ω3 (EPA) and 22:6ω3 (DHA)] in aquafeed with plant oils such as camelina oil [CO, rich in C18 PUFA such as 18:3ω3 (ALA) and 18:2ω6 (LNA)]. The LC-PUFA are essential components in fish diets for maintaining optimal health, physiology and growth. However, most marine fish including Atlantic cod are inefficient at producing LC-PUFA from shorter chain precursors. Since elovl genes encode enzymes that play key roles in fatty acid biosynthesis, we hypothesized that they may be involved in Atlantic cod responses to diets rich in 18:3ω3 and 18:2ω6. Ten members of the cod elovl gene family were characterized at the mRNA level. RT-PCR was used to study constitutive expression of elovl transcripts in fifteen tissues. Some transcripts (e.g. elovl5) were ubiquitously expressed, while others had tissue-specific expression (e.g. elovl4a in brain and eye). Cod fed a CO-containing diet (100% CO replacement of FO and including solvent-extracted fish meal) had significantly lower weight gain, with significant up-regulation of elovl5 and fadsd6 transcripts in the liver as shown by QPCR analysis, compared with cod on a FO control diet after a 13-week trial. Multivariate statistical analyses (SIMPER and PCA) indicated that high 18:3ω3 and/or low ω3 LC-PUFA levels in the liver were associated with the up-regulation of elovl5 and fadsd6, which are involved in LC-PUFA biosynthesis in cod.

Can we count? Enumerating births in two remote Aboriginal communities in the Northern Territory.

OBJECTIVE: To examine the accuracy of birth counts for two remote Aboriginal communities in the Top End of the Northern Territory. METHODS: We compared livebirth counts from community birth records with birth registration numbers and perinatal counts. RESULTS: For 2004-06, for Community 1, there were 204 recorded local livebirths, 190 birth registrations and 172 livebirths in perinatal data. In Community 2, the counts were 244, 222 and 208, respectively. The mean annual number of babies, indicating service requirements for babies and their mothers, ranged from 57 to 68 (depending on source) in Community 1, and from 69 to 81 in Community 2. Most differences were for births to Aboriginal mothers. Births to 'visitors' accounted for 16 births in Community 1 and 30 cases in Community 2. CONCLUSION: Birth registration and perinatal data apparently underestimate community birth counts at a local level. Mobility of Aboriginal women seems to partly explain this. IMPLICATIONS: The differences in birth counts have important implications for local planning in relation to demand on housing, health and education services. The number of births is also a critical data requirement for measuring infant health status, including mortality rates, with measures of disadvantage strongly influenced by the number of births. Aboriginal mobility is not a 'data problem', but an integral part of Aboriginal life that needs to be catered for in administrative data collections in the Northern Territory.