1. This study aimed to determine the minimal duration required for feeding male broilers (Cobb 500) with a flaxseed oil diet while still retaining long chain omega-3 polyunsaturated fatty acid (n-3 LCPUFA) accumulation in the meat at a desirable level. 2. Three groups of broilers (60 each) were fed on a 3% flaxseed oil (high α-linolenic acid (ALA)) diet for either 6, 4 or 2 weeks prior to slaughter. During the remaining time they were maintained on a 3% macadamia oil (low ALA) diet. A fourth group (control, n = 60) was fed on a commercial diet for 6 weeks. 3. No significant difference was observed in growth performance of broilers between groups. The amounts of total n-3 and n-3 LCPUFA in breast and thigh meat were not different between broilers fed the flaxseed oil diet for 4 and 6 weeks, but they were lower (P < 0.001) in those fed the flaxseed diet for only 2 weeks. 4. These results suggest comparable levels of n-3 LCPUFA in the meat can be achieved by only feeding the flaxseed oil diet in the last 3-4 weeks of the growth period; this would result in a ≥ 9.4% reduction in the use of flaxseed oil compared to 6 weeks of feeding; thereby reducing the cost of the enrichment process.

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 aimes to address the hypothesis of whether these effects are specifically due to the variation in the fatty acid composition of the diets, that is, 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 are fed ad libitum on one of six diets containing 4% w/w of either: beef tallow, flaxseed, corn, canola, macadamia, or coconut oil (eight replicates/treatment) for 6 weeks. At harvest, there are no significant differences in productivity parameters nor in the crude lipid content of different tissues between dietary treatments. There are, however, substantial qualitative differences in the fatty acid profiles of all tissues. The levels of specific fatty acids in all tissues except the brain, are 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. The relationship between the diet and breast meat fatty acid composition of 6‐week‐old male broilers (Cobb 500) fed diets containing 4% w/w of either tallow, flaxseed oil, corn oil, canola oil, macadamia oil, or coconut oil. Dietary fatty acid intake determined breast meat fatty acid composition with a strong positive linear correlation for 6 all fatty acid groups (saturates, omega‐9 and omega‐7 monounsaturates, omega‐3, and omega‐6 polyunsaturates and trans, R = 0.938–0.999, P < 0.01).

Manipulation of the fatty acid composition of chicken feed has been shown to be effective for improving the nutritional value of chicken products. Currently, however, evaluation of the effectiveness of this approach requires invasive blood sampling or post mortem tissue sampling of the birds. Preen oil can be collected non-invasively from live birds. So this study aimed to test the hypothesis that the fatty acid composition of preen oil reflects that of the blood. Male and female meat chickens (Cobb 500) were fed a diet supplemented with 4% (w/w) flaxseed oil (high n-3 polyunsaturates) or beef tallow (mostly monounsaturates and saturates) for 6 weeks. Preen oil and whole blood samples (n = 9 birds per sex/diet treatment group) were collected freshly post mortem for fatty acid analysis. Preen oil analysis showed that ~97% of fatty acids were saturates, with a small percentage of n-6 polyunsaturates and traces of other types. There were negligible n-3 polyunsaturates in preen oil. Proportions of some saturated fatty acids were slightly, but significantly, affected by diet (C16:0 (P < 0.05) and C17:0 (P < 0.01)) or by gender (C10:0 and C18:0) (P < 0.05). Some fatty acids with odd numbers of carbon atoms (e.g. C17:0 and C19:0) were found in relatively high concentrations in preen oil, despite not being detectable in either the diet or blood. In conclusion, the fatty acid composition of preen oil does not accurately reflect the fatty acid profile of the blood; it is not, therefore, a suitable alternative for determining fatty acid status of meat chickens.

The content of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) in chicken meat can be boosted by feeding broilers a diet containing α-linolenic acid (ALA, from flaxseed oil), some of which is converted by hepatic enzymes to n-3 LCPUFA. However, most of the accumulated n-3 polyunsaturated fatty acid (PUFA) in meat tissues is still in the form of ALA. Despite this, the levels of chicken diets are being enhanced by the inclusion of vegetable and marine sources of omega-3 fats. This study investigated whether the capacity of chicken for n-3 LCPUFA accumulation could be enhanced or inhibited by exposure to an increased supply of ALA or n-3 LCPUFA in ovo. Breeder hens were fed either flaxseed oil (High-ALA), fish oil (high n-3 LCPUFA) or tallow- (low n-3 PUFA, Control) based diets. The newly hatched chicks in each group were fed either the High-ALA or the Control diets until harvest at 42 days' post-hatch. The n-3 PUFA content of egg yolk and day-old chick meat closely matched the n-3 PUFA composition of the maternal diet. In contrast, the n-3 PUFA composition of breast and leg meat tissues of the 42-day-old offspring closely matched the diet fed post-hatch, with no significant effect of maternal diet. Indeed, there was an inhibition of n-3 LCPUFA accumulation in meat of the broilers from the maternal Fish-Oil diet group when fed the post-hatch High-ALA diet. Therefore, this approach is not valid to elevate n-3 LCPUFA in chicken meat.

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