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.

A Viñado,A C Barroeta,L Castillejos

doi:10.1016/j.psj.2020.06.050

Abstract

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%).

Highlights

Fats and oils are commonly included in broiler feeds to increase the energetic density of the diets; their inclusion is highly dependent on their chemical composition and economic cost
soybean oil (SO) and soybean lecithin (SL) were mainly composed of polyunsaturated fatty acid (FA) (PUFA) and differed in their respective saturated FA (SFA) and monounsaturated FA (MUFA) content
The experimental diets were closely similar between treatments regarding protein and ether extract content; they slightly differed in their respective FA composition

Summary

Introduction

Fats and oils are commonly included in broiler feeds to increase the energetic density of the diets; their inclusion is highly dependent on their chemical composition and economic cost. It has been demonstrated that the saturation degree and composition in different lipid molecular structures have an important influence on performance parameters (Vieira et al, 2006; Ferrini et al, 2008), fatty acid (FA) absorption (Tancharoenrat et al, 2013; Roll et al, 2018), gastrointestinal health. There is a growing interest in the search and use of alternative energy sources in broiler feeding. In this context, coproducts derived from the soybean oil (SO) refinement process represent an economic alternative and permit giving an added value to residual products. SL represents a good source of phosphorus, choline, and energy for broiler chickens (Mateos et al, 2012; Borsatti et al, 2018), and its combination with other fats and oils could

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