It is well documented that lipid digestion is limited in young birds and can affect their performance up to 14 days old. The current strategies to improve fat digestion in birds include the supplementation of dietary biosurfactants such as lecithin and its derivative, lysolecithin.

Lysophospholipids contained in lysolecithin are produced by enzymatic reactions involving phospholipase. The enzyme cleaves off one fatty acid from the phospholipids present in lecithin, resulting in lysophospholipids, which are molecules with higher polarity. Due to its enhanced hydrophilic properties, lysophospholipids have better oil-in-water emulsion capacity than phospholipids (Joshi et al., 2006).

A study has been undertaken to evaluate lysolecithin's ability to improve fat digestion in young birds compared to lecithin.

1. Lysolecithin enhances the hydrolysis of triglycerides

The first experiment involved the in vitro fat absorption of three oil samples. The first sample comprised of only palm oil, a second sample comprised of palm oil supplemented with lecithin, and the last sample comprised of palm oil supplemented with lysolecithin. The degree of lipid hydrolysis was analysed by High-Performance Liquid Chromatography (HPLC) for the triglycerides (TG), and the release of diglycerides (DG), monoglycerides (MG) and free fatty acids (FFA) was measured. Table 1 shows that the amounts of TG hydrolysed, DG, MG and FFA for the sample that comprised of palm oil with lysolecithin are statistically higher than the TG hydrolysed, DG, MG and FFA of the samples that comprised of palm oil with lecithin or palm oil only.

Table 1. Effects of soybean lecithin and soybean lysolecithin on the apparent first-order rate constant (k, × 10 3 min-1) of triglyceride hydrolysis and diglyceride, monoglyceride and free fatty acid released during the in vitro digestion of palm oil in experiment 1.

2. Lysolecithin boosts the absorption of monoglycerides and free fatty acids

In the same experiment, it is observed that the absorption of MG and FFA generated by in vitrohydrolysis is significantly higher for the palm oil with lysolecithin compared to palm oil with lecithin or palm oil alone.

Figure 1. Absorption of monoglycerides and free fatty acids generated during in vitro hydrolysis of palm oil, palm oil with soybean lecithin, and palm oil with soybean lysolecithin by differentiated Caco-2 monolayers and expressed as a percentage of applied monoglycerides and free fatty acids. (Experiment 1).

Data are means of three or more observations per treatment, with error bars indicating the standard error values.

3. Lysolecithin increases AME, dry matter and crude fat digestibility

The second experiment, a broiler digestibility trial, was performed to analyse the effects of lecithin and lysolecithin on the apparent faecal dry matter (DM) and crude fat (CF) digestibility, nitrogen retention and AMEn. As shown in table 2, the treatment group supplemented with lysolecithin provided better results than the other two groups. Interestingly, crude fat digestibility was significantly lower in broilers supplemented with lecithin.

Table 2. Effects of soybean lecithin and soybean lysolecithin on the apparent faecal dry matter, crude fat digestibility, nitrogen retention and AMEn of young broilers that are fed a palm oil-rich diet in experiment 2.

4. Lysolecithin improves birds' performance

A third experiment was conducted to evaluate the performance of young broilers from 0 to 21 days. The birds were allocated to four dietary treatments: a basal diet with soybean oil (2%), a basal diet with lecithin oil (2%), a basal diet with soybean oil and lysolecithin, a basal diet with lecithin oil and lysolecithin. Table 3 shows that the two groups supplemented with lysolecithin expressed a higher body weight, and the best FCR was achieved in the group supplemented with soybean oil and lysolecithin. Also, it is observed that the weight of birds fed with lecithin-based oil only had lower average daily gain compared to those fed with lecithin oil supplemented with lysolecithin.

Table 3. Growth performance of young broilers from day 0 to 21, fed with diets formulated with soya oil or lecithin oil, with or without supplemental lysolecithin. (Experiment 3).

In conclusion, this study suggests that feeding lysolecithin in young birds significantly improves the digestibility and energy values of feed compared to lecithin. It is evident that lysolecithin, not lecithin, contributes significantly to improved digestibility and nutrients absorption in the animal body.

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Article made possible through the contribution of Kemin

Lysolecithin, but not lecithin, improves nutrient digestibility and growth rates in young broilers