Effects of different levels of L-carnitine and fish oil supplementation in diets on performance, egg quality traits and egg yolk fatty acid profile in aged laying hens

Abstract

Nutritional interventions play a pivotal role in sustaining egg production performance and improving egg quality parameters in aged laying hens. The present study was conducted to investigate the effect of L-carnitine (LC) supplementation in diets containing different levels of fish oil (FO) on performance, egg quality parameters and egg yolk fatty acids (FAs) profile in aged laying hens. In this study, 432 laying hens (Hy-line-W36, 65 weeks of age) were used and allocated in a 3 × 3 factorial design with six replications and eight birds per replication. The experimental treatments included diets containing three levels of FO (0.00, 1.50 and 3.00% of the diet) and three levels of LC (0.00, 300, and 600 mg kg-1 of the diet). The results showed that hens treated with 3.00% FO and 300 and 600 mg LC had the highest egg production rate, egg weight and egg mass which was significantly higher than the treatments without FO and LC. With increasing usage level of FO to 3.00% of diet, egg yolk pH was significantly decreased, however, yolk pH was increased when diet was supplemented with 600 mg LC. The percentage of polyunsaturated FAs, the ratio of polyunsaturated FA/saturated FAs and the percentage of omega-3 FAs were increased significantly with increasing FO usage level in the diet. Overall, these findings suggested that dietary supplementation with FO and LC could synergistically improve productive performance and enhance the nutritional value of eggs in aged laying hens.