An analysis of how to improve production of copepods as live feed from tropical Taiwanese outdoor aquaculture ponds

n-3 PUFA biosynthesis by the copepod Apocyclops royi determined by fatty acid profile and gene expression analysis

“…The authors proposed that P. annandalei was either selectively feeding on the more nutritious fish/shrimp meal added to the pond system or the copepods was further metabolising C16:0 and α-linolenic acid (ALA, C18:3n-3) (Rayner et al, 2015). Blanda et al (2017) reported that in 2013–2014 the same discrepancies in content of C18:1n-9 was not observed, while it was still present for DHA. The lack of C18:1n-9 suggested a phytoplankton-based diet, but this could not account for the observed high DHA content in the copepods.…”

“…Two species of copepods dominate the aquaculture ponds: the calanoid Pseudodiaptomus annandalei and the cyclopoid Apocyclops royi (Blanda et al, 2015, 2017; Su et al, 2005). This community reduction raises the question of whether the two species have crucial traits in common in order to occupy the ecological niche of the environmentally harsh conditions of this artificial habitat.…”

“…In a summer study in 2012 and a year-long study in 2013–14, it was reported that the copepods were experiencing prey ad libitum (Blanda et al, 2015, 2017). Phytoplankton densities were high, and the seston concentration was a minimum of 7540±1630 µg C l −1 in 2012 and an estimated minimum of 3000 µg C l −1 in 2013–2014.…”

“…Blanda et al (2017) reported that the PUFA content in seston was low all year round (23.2–34.4% of total FA content). The essential FAs – EPA and DHA – were especially low during spring, summer and fall (<10% each).…”

“…However, P. annandalei consistently had a FA profile with higher PUFA content (33.5–74.1%), and even reached a DHA content of 46.6% of total FA in January 2014. Furthermore, Blanda et al (2017) reported that the mean DHA content in the seston was as low as 2.0±1.1% of total FA during a July/August campaign. Considering the high metabolic rate in tropical organisms, this suggests that occasionally the copepods are PUFA-starved.…”