Effect of lowering the amount of dietary linoleic acid on tissue omega-3 fatty acid contents of broilers fed supplemental flaxseed oil from 18 to 35 days of age

Abstract

Chickens can hepatically synthesize very long-chain omega-3 ( VLC n-3 ) polyunsaturated fatty acids ( PUFA ) from α-linolenic acid ( ALA ; 18:3 n-3); however, the efficiency is attenuated by linoleic acid ( LA ; 18:2 n-6), which competes with ALA for the same elongase and desaturase enzymes. Here, we fed broilers supplemental ALA-rich flaxseed oil ( FLAX ) while reducing the dietary level of LA to determine if greater tissue n-3 PUFA enrichment could be attained. Male Ross 708 chicks were fed a common starter diet from day 1 to 17. On day 18, 4 pens of 36 birds were each fed one of 5 diets: (1) reduced-LA/low-n-3 fatty acid base + 60 g/kg high-oleic sunflower oil ( HOSO ); (2) reduced-LA base + 50 g/kg FLAX+ 10 g/kg HOSO; (3) standard-LA base + 50 g/kg FLAX + 10 g/kg HOSO; (4) standard-LA base + 50 g/kg FLAX + 10 g/kg high-LA safflower oil; and (5) standard-LA base + 50 g/kg FLAX + 10 g/kg fish oil. There was no effect ( P > 0.05) of diet on day-35 BW, FCR, breast, thigh, or abdominal fat pad weights, while birds fed diet 2 had higher thigh ALA, total n-3, and total VLC n-3 PUFA than birds fed diets 1, 3, and 4. Breast data followed a similar pattern, although the differences were not significant ( P > 0.05). In conclusion, reducing the LA content of a FLAX-supplemented diet promoted greater deposition of n-3 PUFA in broiler muscles, although the highest tissue contents of VLC n-3 PUFA were observed in birds fed fish oil (diet 5).