Recommended daily inclusion 1 - 5 grams per animal per day.
In Norwegian trials weight gain and general health improvement over controls was observed when Ascophyllum was added to the rations of 2,356 chicks otherwise well-balanced but without yeast, grass meal or cod liver oil (Høie and Sandvik, 1955).
In trials involving 3,052 chicks on rations deficient in certain vitamins, particularly A and B, marked improvements were observed in growth, feed efficiency and health when Ascophyllum was included (Høie and Sandvik, 1960).
Use of seaweed is beneficial if the ration is deficient in Vitamin A or B2 (Jensen, 1972). In pullet trials, egg production improved when 8% of Ascophyllum meal was added to the diet of 544 White Leghorns, after egg-laying had dropped 70 - 80% on a similarly deficient diet - (Høie and Sandvik, 1955).
In the USA 6,000 hens were fed 1.25% Ascophyllum in their normal ration. The proportion of thin-shelled eggs fell from 3% to 1.9%. After three months the seaweed was stopped. The proportion of thin-shelled eggs returned to 3% (SSRA Report, 1967).
Modes of action may include:
- Fucoxanthin present in vitamin A producing a xanthophyll in the gut (90-250 mg/kg) may improve egg yolk colour
- Carotenoids present at 30-60 mg/kg and rich trace elements may improve egg shell strength
- Organic minerals, trace elements and vitamins may be more readily assimilated than in mineral formulations
- Disease resistance may be enhanced by a complete balance of micronutrients
- Seaweed nutrients including polysaccharides which benefit gut flora may enhance nutritional value particularly of poor quality rations
- Low energy-high fibre also improves intestinal function; combats feather picking and cannibalism