Effects of Lecithin Supplementation in Feed of Different fat Levels on Serum Indexes and Liver Health of Laying Hens

Abstract

The aim of this experiment was to investigate the effect of soy lecithin on serum-related indicators and liver health in laying hens under the influence of high-fat diets. 180 peak laying hens at 40 weeks of age were randomly assigned to one of the four diets using a 2 × 2 factorial and fed for 5 weeks. The results showed that compared to the low-fat group, the high-fat group had lower egg production (p < 0.05) and higher average daily feed intake and feed-to-egg ratio (p < 0.05). At the 21st day, the serum levels of triglyceride (TC) and superoxide dismutase (SOD) were higher (p < 0.05), high-density lipoproteins cholesterol (HDL-C) levels were lower (p < 0.01), catalase (CAT) activity was lower (p < 0.05), TC and malondialdehyde (MDA) levels in liver were higher (p < 0.01) and SOD activity in liver was lower (p < 0.05) in layers supplemented with soy lecithin. CAT activity in serum was increased (p < 0.01) and total antioxidant capacity (T-AOC) activity in the liver was decreased (p < 0.05) after increasing the dietary fat concentration. The addition of soy lecithin and the increase in dietary fat concentration had a highly significant interaction on serum CAT activity and liver TC content in layers (p < 0.01). At the 35th day, the serum alanine aminotransferase (ALT) activity was higher (p < 0.01), serum glutathione peroxidase (GSH-Px) and CAT activity were higher (p < 0.05), and serum triglyceride (TG) content and total T-AOC capacity activity were lower (p < 0.05) in layers supplemented with soy lecithin. Increasing dietary fat concentration decreased alanine aminotransferase (ALT), aspartate aminotransferase (AST) and GSH-Px activity in serum (p < 0.05). However, it increased TG and MDA content in liver (p < 0.05), and highly decreased SOD content in liver (p < 0.01) in layers. The addition of soy lecithin and increasing dietary fat concentration had a highly significant reciprocal effect on serum ALT viability and CAT viability (p < 0.01) and liver TG and MDA content and SOD viability (p < 0.05) in layers. In conclusion, feeding high-fat diets will adversely affect the laying performance of laying hens, while long-term addition of lecithin can improve the blood lipids and liver lipids of laying hens, enhance the antioxidant capacity of the liver, and maintain liver health.