Replacement of Palm Oil with Soybean Acid Oil in Broiler Chicken Diet: Fat Digestibility and Lipid Class Content along the Intestinal Tract

Abstract

This study aimed to evaluate the replacement of palm oil (P) with increasing levels of soybean acid oil (SA), a by-product of soybean oil (S) refining, on lipid class content and fatty acid (FA) digestibility in the intestine and excreta of chickens at 11 and 35 days (d). Five experimental diets were obtained by supplementing a basal diet with 6% of P (P6), 6% of SA (SA6), 4% of P + 2% SA (P4-SA2), 2% of P + 4% of SA (P2-SA4) and 6% of S (S6). A total of 480 one-d-old female broiler chickens (Ross 308) were housed in metabolic cages (6 cages/treatment, with 16 birds/cage). Replacing P with SA improved fat absorption at 11 and 35 d (p < 0.05), but not feed AME values and saturated FA (SFA) digestibility at 11 d. As age increased, the absorption of SFA and free fatty acids (FFA) improved, and the contribution of the upper ileum to FA absorption increased (p < 0.05). At 35 d, SA6 (56% FFA) and P2-SA4 (40% FFA, 2.6 unsaturated-to-saturated FA ratio) could replace S6 without impairing fat utilization. The replacement of P with SA represents a suitable strategy to use this by-product.

Keywords: acid oils; broiler chickens; fat by-products; fat digestibility; free fatty acids; intestinal tract; lipid classes; poultry.

Figure 1

Free fatty acids (FFA) content¹ in the feed, upper jejunum, lower jejunum, upper ileum, lower ileum, and excreta for the five different diets; with 6% of palm oil (P6), blend with 4% palm oil +2% soybean acid oil (P4-SA2), blend with 2% palm oil +4% soybean acid oil (P2-SA4), with 6% of soybean acid oil (SA6) and with 6% soybean oil (S6) in (a) 11-d-old broiler chickens and (b) 35-d-old broiler chickens. ¹ FFA concentration (mg/g)/Ti concentration (mg/g) in each intestinal segment and excreta. Per each diet, means values are obtained from means of 6 replicates with 12 chickens/replicate at 11 d, and 2 chickens/replicate at 35 d. a–d: for each intestinal segment and excreta, different letter indicates significant differences (p ≤ 0.05).

Figure 2

Contribution of each intestinal segment to the apparent fatty acid digestibility, calculated as a proportion of total digestibility reached at the lower ileum, along the intestinal tract for the five different diets; with 6% of palm oil (P6), blend with 4% palm oil +2% soybean acid oil (P4-SA2), blend with 2% palm oil +4% soybean acid oil (P2-SA4), with 6% of soybean acid oil (SA6) and with 6% soybean oil (S6) in (a) 11-d-old broiler chickens and (b) 35-d-old broiler chickens. TFA (total fatty acids), PALMITIC (C16:0), STEARIC (C18:0), OLEIC (C18:1 n-9) and LINOLEIC (C18:2 n-6) acids. Values are means of 6 replicates per each diet with 12 chickens/replicate at 11 d, and 2 chickens/replicate at 35 d. ^a–c: within the same intestinal segment, columns not sharing a common letter are significantly different (p < 0.01).