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Synopsis
Three trials were performed during consecutive years, involving a total of 972 Leghorn hens, in order to compare all‐vegetable layer diets of marginal protein con‐tent based either on milo or on maize as the only cereal grain.
Under the conditions of this study the only consistent, and at times significant, effect due to the source of cereals was the reduction of egg size due to milo. Methio‐nine supplementation of milo diets equalised egg weights. The calculated sulphur amino acid requirement for optimal egg size appeared to be about 560 mg/bird d.
Maize contains decidedly higher levels of linoleic acid than milo, especially on a whole grain basis (2.3% as compared with 1.5%); the difference is reflected in the fatty acid pattern of the yolk lipids of eggs produced by hens‐fed these diets. The dietary to yolk linoleic acid ratio appeared to be 1 to 9–10, for dietary levels ranging from 1.0 to 1.7%.
Milo‐soya diets containing 1.1–1.2% dietary linoleic acid were adequate for optimal egg size, on the condition that methionine requirements had been met, that daily food consumption was not less than 110 g/bird, and that the pre‐layer diets had been rich in linoleic acid. If the pre‐layer diets had been composed of practical ingredients relatively low in this essential fatty acid, a minimum level of 1.5–1.6% dietary linoleic acid was indicated. Acidulated soya soapstock proved a practical linoleic acid supplement.
Notes
Contribution from The Volcani Institute of Agricultural Research, Bet Dagan, Israel. 1971 Series, No. 1899‐E.