I understand there is considerable interest in adding high levels of fish oil to diets for laying hens as a means of (a) enhancing health status, and (b) producing eggs rich in omega-3 fatty acids. As much as 3% is recommended in some cases, especially when using deodorised fish oil, that comes with a price premium!
Now, we all know that normal fish oil, about above 1% added as straight oil or through fish meal, gives eggs a fishy smell that most consumers find objectionable. In a Canadian study, even 2% deodorised menhaden oil made eggs smell a bit fishy!
What is less known, is that too much fish oil can actually reduce egg weight. I have seen this in an older trial, where egg weight was reduced 0.35 grams per 1% fish oil in the feed.
And, in a most recent study from Iran, high levels of fish oil not only reduced egg production but it also affected sexual maturity delaying the growth of the reproductive system in hens. And, there is also at least one more British study that implicated high levels of fish oil with reduced reproductive performance in pigs.
So far, I have been skeptical recommending high levels of fish oil to my customers who were looking into getting into the ‘designer’ egg market, preferring other means of achieving the desired increase in omega-3 fatty acids. But, I cannot deny, and there is evidence to that as well, that feeding fish oil enhances the immune status animals.
What is your take on all these?