4. Discussion
4.1. Effect of diet on fatty acids
The results from the current study indicate that the concentrations
of the long chain n−3 fatty acids EPA + DHA can be elevated two
fold by supplementation of algae in small amounts over the level present in lambs fed annual ryegrass sub-clover hay. Animals fed with the
Basal diet had EPA + DHA levels that were similar to lambs grazing a
senesced annual ryegrass pasture of low nutritive characteristics, but
greater than the levels produced by lambs fed with feedlot pellets as observed in a 3 year study covering approximately 6000 lambs across 8
lamb production sites of Australia (Ponnampalam et al., 2014a). The
levels were also greater than the levels produced by lambs grazing kikuyu pasture in the Western region of Australia (Kitessa et al., 2010).
However, the level in the lambs fed with the basal diet was lower
than the values reported for lambs grazing predominantly Lucerne
perennial pasture (33.5 mg/100 g meat) or senesced annual pasture
with Lucerne hay and grain supplements (29.4–31.5 mg/100 g meat)
in the autumn season (Ponnampalam et al., 2012a). In the latter study
it was reported that including good quality Lucerne hay (CP — 15.9%
DM; ME — 9.1 MJ/kg DM) for lambs grazing senesced annual ryegrass
pasture of low nutritive characteristics can be a strategy to elevate the
long chain n−3 PUFA and the vitamin E concentration of meat.