Soybean lecithin as an alternative energy source for grower and finisher broiler chickens: impact on performance, fatty acid digestibility, gut health, and abdominal fat saturation degree

An experiment was performed to assess the inclusion of soybean lecithin (SL) in the replacement of soybean oil (SO), for grower and finisher broiler chicken diets (up to 15 d of life), and its effects on performance, fatty acid (FA) absorption, gut health, and saturation degree of the abdominal fat pad (AFP). A total of 1,440 female Ross-308 chickens were distributed in 60 pens and were fed 5 experimental diets. The control diet (T1) was supplemented with SO (grower and finisher diets at 2.00%), and 4 levels of SL were included in replacement: T2 (0.25% in grower and 0.50% in finisher diets), T3 (0.50% in grower and 1.00% in finisher diets), T4 (0.75% in grower and 1.50% in finisher diets), and T5 (1.00% in grower and 2.00% in finisher diets). At day 39, titanium dioxide was added to finisher diets at 5 g/kg to perform a digestibility balance. At day 46, AFP, tissue, and gut digesta samples were collected to characterize FA digestibility, adipose saturation degree, microbial groups, and histomorphometry. No effects were associated with SO replacement by SL on performance (P > 0.05), ileal digestibility of total, saturated and monounsaturated FA (P > 0.05), nor jejunal morphology (P > 0.05). Total replacement of SO by SL reduced ileal absorption of polyunsaturated FA (P < 0.02) and increased jejunal Lactobacillus spp. counts (P = 0.049). Higher levels of SL inclusion (T4 and T5) lowered polyunsaturated FA concentration of the AFP (P = 0.002) and, thus, slightly reduced its unsaturated-to-saturated FA ratio (P = 0.005). Soybean lecithin inclusion did not modify performance parameters, total FA absorption, nor jejunal morphology, however caused changes on polyunsaturated FA absorption, jejunal microbiota, and saturation degree of the AFP. The study demonstrates that soybean lecithin can be included, in combination with or in replacement of soybean oil, as an alternative energy source for grower (up to a 1%) and finisher broiler diets (up to 2%).