The effects of different levels of canola oil (0.0, 2.0, 4.0 and 6.0 per cent) on the performance of laying hens and egg shell quality and fatty acid composition were investigated by Mehmet Gül of Atatürk University in Erzurum in Turkey and co-authors there and at Mustafa Kemal University.

The study, published in International Journal of Poultry Science, involved a total of 96 chickens, 24 chickens in each group were used in the four groups. Feed and water were offered as ad libitum.

Egg production was recorded daily and feed intake was recorded weekly. Egg quality criteria were determined in 12 eggs from each group. Egg yolk fatty acid profile was determined by gas chromatography.

The use of increasing levels of canola oil decreased egg production, egg weight and daily feed intake; in the group including six per cent canola oil, by 70.98 per cent, 61.68g, 109.52g compared to the control, respectively. Feed conversion was not affected by dietary treatment.

Supplementation with canola oil increased the yellow colour of the eggs and the egg-yolk index.

On day 21, Thiobarbituric Acid Reactive Substance (TBARS) value - a measure of oxidation - significantly increased with increasing levels of canola oil (13.60, 14.78 and 16.68, respectively). On day 42, the TBARS values were not significantly different

.

Egg yolk lipid profile was not significantly affected by the level of canola oil in the diet but it was slightly lower for the control group.

Blood serum lipid profile decreased as the percentage of canola oil increased, as did the monoacyldiglycerol level.

The level of monounsaturated fatty acid (MUFA; oleic acid) in the egg yolk fat was 36.05 per cent for the control group, which was significantly lower that for the other groups, for which it was 42.94, 42.14 and 43.51 per cent, respectively for the birds receiving two, four and sex per cent of canola oil, respectively.

The researchers concluded that canola oil supplementation of the layer diet can be effective for the production of MUFA-rich functional eggs.

Reference

Gül M., M.A. Yörük, T. Aksu and Ö. Kaynar. 2012. The effect of different levels of canola oil on performance, egg shell quality and fatty acid composition of laying hens. International Journal of Poultry Science. 11(12):769-776.

Further Reading You can view the full report by clicking here.

March 2013