Effects of dietary solid and liquid lysophospholipid application methods on growth performance, nutrient digestibility, enzyme activity, nutrient-transporter mRNA abundance, intestinal morphology, and meat quality in broiler chickens fed energy-reduced diets.

The biological efficacy of dietary lysophospholipids (LPLs) in broiler diets may be significantly modulated by their technical delivery methods. This study evaluated the effects of direct solid addition and liquid applications (oil-water pre-emulsification or pure oil pre-mixing) of LPLs on growth performance, nutrient digestibility, intestinal morphology, and gene expression in broilers fed energy-reduced diets. A total of 480 one-day-old male Ross 308 broilers were assigned to five treatments, with eight replicate pens of 12 birds. The treatments were a basal diet (T1), an energy-reduced diet (T2; 100 kcal/kg less metabolizable energy [ME]), and T2 supplemented with LPLs. The supplemented treatments received solid LPLs at 250 g/t (T3), oil-water pre-emulsified liquid LPLs at 500 g/t (T4), or oil-premixed liquid LPLs at 500 g/t (T5).Reducing dietary energy significantly deteriorated the overall feed conversion ratio (FCR) (P < 0.05). Broilers in liquid LPL groups exhibited higher final body weights and lower d21-42 FCR compared to both T2 and T3 groups (P < 0.05), with no differences between T4 and T5. All LPL treatments improved the digestibility of crude fat, gross energy and dry matter on days 21 and 42 (P < 0.05), while liquid methods further maximized dry matter digestibility at day 42 (P < 0.05). Morphologically, LPL supplementation restored the jejunal villus height to crypt depth ratio compromised by the low-energy diet (P < 0.05). Compared with solid addition, liquid LPLs increased the relative mRNA abundance of L-type amino acid transporter 1 (LAT1), cationic amino acid transporter 1 (CAT1), fatty acid-binding protein 1 (FABP1). In conclusion, liquid LPL applications are superior to traditional solid addition in enhancing broiler finisher growth performance, nutrient digestibility, and transporter gene expression in reduced-energy diet. Notably, direct pre-mixing of LPLs in dietary oil is as highly effective as external oil-water pre-emulsification, offering an optimized strategy for reduced-energy dietary utilization.