The effect of different dietary fats on the fatty acid composition of several tissues in broiler chickens

The type of fat used in formulating broiler chicken diets can affect growth performance, influence the fatty acid composition of different tissues and has consequences for bird health and nutritional value for the consumer. This study aimed to address the hypothesis of whether these effects are specifically due to the variation in the fatty acid composition of the diets, i.e. the proportion of different saturates, monounsaturates (n-7 and n-9) or polyunsaturates (n-3 or n-6), or other factors (physical properties, solid/liquid and source, plant/animal). A total of 480 male Cobb 500 broilers were fed ad libitum on one of six diets containing 4% w/w of either: beef tallow, flaxseed, corn, canola, macadamia or coconut oil (8 replicates/treatment) for six weeks. At harvest, there were no significant differences in productivity parameters nor in the crude lipid content of different tissues between dietary treatments. There were, however, substantial qualitative differences in the fatty acid profiles of all tissues. The levels of specific fatty acids in all tissues except the brain, were positively correlated with the levels of the same fatty acids in the diet however, the strength of the correlations varied between different fatty acids. Practical applications: The results of the current study demonstrate that the dietary fatty acids types and proportions largely determines the fatty acid profile in edible tissues (meat, adipose, liver and heart). The strong correlations and regressions between diet and tissue fatty acid levels validate the ability to predict the tissue fatty acid profile of broilers based on their dietary fat composition. Contrary to our hypothesis, dietary fat type had no influence on the growth parameters which makes us speculate whether such differences in similar studies only become apparent in situations where the birds are also under some level of environmental or social stress. This information will assist poultry feed manufacturers and broiler producers in making decisions about selection of fats with known nutritional and health benefits for inclusion in chicken feed.