| Popis: |
Ninety Isa Brown laying hens aged 28 weeks, kept in individual cages, were randomly divided into 6 groups of 15 birds each. Six isoproteinous diets differing in crude fat content and fatty acid (FA) composition were prepared. The source of added fat was linseeds (50 g/kg diet), regular cultivars (Omega and Opal) with a high content of α-linolenic acid (HA), or a modified cultivar (Linola) with low α-linolenic acid- and high linoleic acid (LA) contents, soyabean oil, or LA linseed oil (20 g/kg diet). The control diet, with no fat supplement, contained 19 g, while the experimental diets, 38 g of crude fat per kg. The diets were fed for a 12-week and eggs were collected for chemical analysis at weekly intervals. The dietary fat level had no effect on the fat level in egg yolks. Eggs from hens fed diets with HA linseeds contained 3 times more α-linolenic acid, 2.5 times more EPA (C 20:5n-3 ) and DHA (C 22:6n-3 ) and 27% less arachidonic acid (C 20:4n-6 ) than control eggs (P |
