Effects of reducing dietary methionine, linoleic acid, choline and increasing energy on performance and eggshell quality in aged laying hens

An experiment was conducted to determine whether egg quality during the late stage of egg production can be improved by using diets that are effective in reducing egg size. The experiment was conducted in completely randomized design with six treatment groups and four replicates each with ten hens from 94 to 106 wk of age. Three 28-d periods used for different dietary factors including: 1) Control (C); 2) Control with low (0.24%) methionine (LM); 3) Control with low (0.42%) linoleic acid (LLA); 4) Control with high (3000Kcal/kg) energy (HE); 5) Control with low (0.2, 0.42%, no supplement) methionine, linoleic acid, choline and high energy (3000Kcal/kg) (LMLLA-LCH-HE) and 6) Control with low (no supplement) choline (LCH). The data were analyzed using the General Linear Model procedure of SAS software (1992). Overall feed intake was significantly (P<0.05) lower for the hens fed HE diets compared to the control. Overall egg weight and albumin weight was significantly (P<0.05) lower for the hens fed LM and LM-LLA-LCH-HE compared to the control. Overall egg mass, egg production and eggshell thickness was not affected by treatments. The results indicate that certain manipulations of methionine, choline, linoleic acid, energy or the combination of these nutrients have the potential to reduce egg weight without affecting egg mass, egg production and eggshell thickness during the latter stage of the egg production cycle.