Dietary supplementation of lysolecithin improves growth performance of piglets fed a low-nutrient density diet by modulating nutrient utilization and metabolism.

Reducing dietary nutrient density may lower the feed cost but compromise the growth performance in piglets. Given the ability of lysolecithin (LPI) to enhance nutrient utilization, its supplementation may help piglets adapt to a low-nutrient (LN) diet. This study aimed to investigate the effects of dietary LPI supplementation on growth performance, nutrient utilization, metabolism, and muscle development in piglets fed a LN diet. A total of 96 nursery piglets (17.0 ± 0.2 kg in initial body weight [BW] and 50 d of age) were randomly assigned to three groups in a randomized complete block design and received either the normal-nutrient diet (CON), a LN diet, or the LN diet supplemented with 400 mg/kg lysolecithin (LN-LPI) for 28 d. Each dietary treatment included 8 replicates of 4 piglets each. Results showed that the LN-LPI diet improved the average daily gain (ADG; P = 0.040) during the first two weeks, feed-to-gain ratio (F:G; P = 0.032), and BW (P = 0.065) throughout the experimental period, reaching levels comparable to those of piglets in the CON group. Compared with the LN diet, the growth-promoting effect of LPI may be attributed to its role in increasing the digestibility of ether extract (EE; P < 0.001) and gross energy (GE; P = 0.022) in diets, as well as increasing the relative weight of psoas major muscles (PMM) and the EE (P = 0.049) and crude protein (CP) content (P = 0.007) in muscle. Accordingly, compared with the LN diet, LPI supplementation decreased the blood urea nitrogen (P = 0.003) and total cholesterol (TC) concentrations (P = 0.017), and increased total superoxide dismutase (T-SOD) levels in plasma (P = 0.005) and liver (P = 0.006), along with the lower malondialdehyde (MDA) levels in blood (P < 0.001) and liver (P = 0.003). In addition, microarray analysis indicated that dietary LPI supplementation promoted expression of lipid synthesis and transport-related genes in the liver (FAS, P = 0.040; FABP5, P = 0.001; and SLC27A6, P = 0.025), and amino acid (AA) transport and synthesis-related genes (LAT, P = 0.021; LAMC3, P = 0.004), compared with the LN diet in muscle. In conclusion, this study demonstrated that the LN-LPI diet mitigated the compromised growth performance commonly observed under nutrient restriction, potentially mediated by improving nutrient utilization and redox status, and modulating lipid and protein metabolism.