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The aim of the present study is to assess the effect of the dietary free fatty acid (FFA) content and dietary fat saturation degree on the fatty-acid (FA) digestibility and lipid-class content along the gastrointestinal tract and excreta in broiler chickens. The 8 experimental diets resulted from replacing crude soybean oil with soybean acid oil from chemical refining, or crude palm oil with palm FA distillate from physical refining. Thus, there were 4 soybean and 4 palm diets with 6% added fat varying in their FFA% (5, 15, 35, and 50%). Samples of digestive content (gizzard, duodenum, jejunum, and ileum) and excreta were collected at 14 D for the determination of the FA digestibility and lipid-class content. The total FA digestibility coefficients reported for the chickens fed S diets in the jejunum, ileum, and excreta were higher than for those fed P diets (P ≤ 0.02). The general greater digestibility of the unsaturated diets was mainly explained by a higher contribution of the ileum to the absorption of saturated FA. The dietary FFA content mainly affected the FA absorption process. The diets with 50% FFA presented lower saturated FA digestibility coefficients in the jejunum and ileum (P ≤ 0.03), and higher content of FFA in the ileum and excreta (P ≤ 0.014), in comparison to the diets with 5% FFA. The 15% FFA diets were not different from the 5% FFA diets, regarding the saturated FA digestibility in the jejunum and excreta, and the FFA content in the ileum and excreta. It was concluded that unsaturated diets with moderate content of dietary FFA (up to 15%) could be used in broiler-chicken starter diets, as they led to similar FA absorption and performance results to the diets with the lowest dietary FFA content. From the present study, it has also been concluded that dietary saturated FA content has a greater impact on FA absorption than the dietary FFA content has. [ABSTRACT FROM AUTHOR]

The aim of the present study is to evaluate the effect of the dietary fat saturation degree and age on the lipid class (TAG, DAG, MAG, and FFA) composition and fatty acid digestibility along the gastrointestinal tract (GIT) and excreta in broiler chickens. A total of 120 one-day-old female broiler chickens were randomly distributed in 2 dietary treatments (6 cages/treatment), which resulted from the supplementation of a basal diet with 6% of soybean oil or palm oil. Two digestibility balances were carried out at 14 and 35 d and fatty acid digestibility and lipid class composition were determined in the gizzard, duodenum, jejunum, ileum, and excreta. Along de GIT, both fatty acid digestibility and lipid class composition were influenced by the dietary fat source and the age of the chickens. The absorption of the unsaturated fat was more efficient and faster than it was for the saturated fat. The ability of adult chickens to absorb fat was higher than for young chickens. The results show that the duodenum is the main place of fat digestion (hydrolysis), and the jejunum the main place of fat absorption. The role of the ileum on fat absorption is very important, as it is the last segment of the GIT where the absorption of fatty acids has been described. Thus, it was the contribution of the ileum that was responsible for the higher fat utilization observed for animals fed the unsaturated diet than for those fed the saturated diet at 14 d, and it was also responsible for the improvement on the utilization of the saturated diet between 14 and 35 d. All the results suggest that the absorption of fatty acids is more limiting than is hydrolysis, because the main differences were observed in the jejunum and ileum, where the absorption of fatty acids takes place. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate the use of crude soybean lecithin (L) as an alternative energy source in broiler feeding and to study its influence on performance, fatty acid (FA) digestibility between 9 to 11 D and 36 to 37 D, feed AME content, and the FA profile of the abdominal fat pad (AFP). A basal diet was supplemented at 3% with soybean oil (S; experiment 1) or a monounsaturated vegetable acid oil (A; experiment 2) and increasing amounts of L (1, 2, and 3%) were included in replacement. The inclusion of L did not modify performance results (P > 0.05). In starter diets, the replacement of S by L reduced feed AME content (P < 0.001) and lowered PUFA digestibility (P = 0.028), whereas in the grower-finisher phase, a blend of 2% of S and 1% of L did not modify feed AME content or FA digestibility. When L was included instead of A, no effects on feed AME value and total FA digestibility (P > 0.05) were shown in the starter phase, whereas in grower-finisher diets, a blending of 2% of A and 1% of L enhanced feed AME content (P < 0.001) and total FA digestibility (P = 0.001). The FA profile of the AFP reflected the FA composition of the diets. Crude soybean lecithin represents an alternative energy source for broiler chickens, and it can be used in growing-finishing diets in replacement of 1% S. The best option to include both alternative fats (L and A) was 2% of L with 1% of A in starter diets and 1% of L with 2% of A in grower-finisher diets because they showed positive synergic effects. The results suggest that dietary FA profile have a bigger impact on the AFP saturation degree than the different dietary lipid molecular structures. [ABSTRACT FROM AUTHOR]