GM oil improves the nutritional value of chicken
Take Home Message: Feeding broilers stearidonic acid increases levels of ‘healthy’ fats and reduces “taints” compared to feeding fish oil.
Feeding broilers stearidonic acid produced meat with nutritionally significant concentrations of LC n-3 PUFA while reducing the taint detected when birds were fed fish oil.
That was the finding of a trial, carried out by researchers at the University of Reading, to determine what the effects on meat fatty acid composition and sensory characteristics were when broilers were fed an oil derived from soyabean genetically modified to produce high concentrations of C18:4 n-3.
Enriching chicken meat with long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) is a viable means of increasing population intakes (minimum recommended 450 mg/d, SACN, 2004) of these essential fatty acids,” Caroline Rymer told delegates at the British Society of Animal Science’s annual conference.
Feeding broilers fish oil to achieve this causes problems with taint in the meat, whereas feeding an oil rich in C18:3 n-3 (LNA) does not result in the deposition of LC n-3 PUFA. Stearidonic acid (C18:4n-3) is further down the conversion pathway of LNA to LC n-3 PUFA and appears to be converted much more efficiently by humans to LC n-3 PUFA than LNA.
“So feeding birds an oil rich in C18:4n-3 may therefore result in more enrichment of poultry meat with n-3 PUFA other than LNA, without the taint associated with feeding fish oil,” added Dr Rymer, explaining the rationale behind her work.
Male, day old Ross 308 chicks were reared for 14 days in a single group on a common starter diet containing conventional soyabean oil. On 15 day the birds were weighed and randomly allocated to one of 24 pens (five birds per pen).
Pens were then randomly allocated to one of three treatment groups and birds were fed identical grower (days 15-28) and finisher (29-50 d) diets supplemented with either CON oil, fish oil or SDA.
Samples of skinless breast and leg meat were taken from all birds, composited by pen for analysis of fatty acid composition and composited by treatment for sensory analysis (quantitative descriptive analysis with ten assessors scoring meat between 0 and 100 for a range of descriptors), using either freshly cooked meat (breast and leg meat) or reheated meat (leg meat only).
“And we found that fish oil reduced LNA and increased LC n-3 PUFA content of meat and that SDA increased LC n-3 PUFA content compared with CON and total n-3 content was considerably higher with both fish oil and SDA compared with CON,” said Dr Rymer.
“Broiler diet had no significant effect on the meat’s appearance, or on the aroma or flavour of breast meat. However, fishy aromas, flavours and aftertastes were detected in the leg meat of fish oil fed birds, particularly when the meat was reheated. And fishy notes were also detected in the reheated leg meat of birds fed SDA,” she added.
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