Impact of Dried Thyme Leaf Meal on Production Performance, Egg Quality and Blood Parameters of Laying Hens

The use of commercially extracted phytogenic compounds to maintain poultry health and productivity in the absence of in-feed antibiotics is prohibitively costly in developing countries.

The goal of the study is to determine the effect of dietary supplementation with Thymus schimperi leaf meal (TLM) on production performance, egg quality and haemato-biochemical parameters of Bovan brown layers.

A total of 96 laying hens at 25 weeks of age were randomly assigned to 4 treatments with 6 replications each. The treatments include the control (standard commercial laying diet), TLM1.5 (control + 1.5% TLM), TLM2.5 (control + 2.5% TLM) and TLM3.5 (control + 3.5% TLM). Egg production, feed intake and feed conversion ratio were recorded for each replicate. Two eggs per replication were used to measure internal and external egg quality traits on a monthly basis. At the end of the trial, blood samples were collected from 2 birds/replicate for the determination of albumin, uric acid, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, luteinizing hormone, prolactin and progesterone.

All blood parameters were within the normal ranges of the breed. Egg production, feed conversion ratio, internal egg quality traits and external egg quality traits of hens fed diets containing 2.5% TLM were significantly higher than the control. Furthermore, diets containing 2.5% TLM led to a significantly reduced feed conversion ratio compared to all other dietary treatments.

In conclusion, 2.5% TML is recommended to improve egg production and egg quality without adverse effect on hen health.