Impact of dietary L-carnitine supplementation on blood parameters and duodenal alterations in laying hens at the end of production

L-carnitine is an important nutritional supplement in the poultry industry, contributing to improved growth, production, and overall health of the birds. However, by the end of the production cycle, the endogenous synthesis of L-carnitine (LC) is often insufficient. This study aimed to evaluate the effects of dietary L-carnitine supplementation on blood parameters and duodenal structure in Ross laying hens during the last production phase. A total of 40 Ross strain laying hens, aged 70 weeks, were selected. The control group was administered a basal diet, while the experimental groups received the same diet supplemented with 100, 250, or 500 mg of L-carnitine per kg of the basal diet. The experimental period lasted for 56 days. Serum concentrations of cholesterol and total protein were not significantly affected by L-carnitine supplementation; however, triglyceride concentration and LDL levels were notably reduced. Furthermore, L-carnitine supplementation enhanced the villus perimeter and increased the villus length/crypt depth ratio. Importantly, the supplementation of 250 mg/kg of L-carnitine had a positive impact on duodenum structure and led to decreased levels of AST and ALP. In conclusion, the incorporation of 250 mg/kg of L-carnitine into the diet of laying hens significantly improved duodenal structure, reduced lipid peroxidation, and demonstrated antioxidant effects.