Effects of different levels of dried tomato pulp on production performance of layers and egg internal quality traits during different storage times and temperatures

Introduction Tomato, one of the most popular vegetable used in food preparations is used to processing and production of tomato juice. During processing, large amount of pulp including seeds is produced which can be used in poultry feeding. Tomato pulp is known as a protein source in poultry diets but its seeds have strong antioxidant such as ß-carotene and lycopene) Friedman et al, 2000). Some researchers used tomato pulp up to 19-20% in laying hen diet and reported no significant changes in performance criteria (Salajegheh et al, 2012; Calislar and Uygu, 2010). The positive effects of antioxidant compounds in some plants such as tomato on egg quality have been reported previously by some researchers (Sahin et al, 2008; Uuganbayar, 2005). It have been documented that layer hens meet some oxidative attacks during force molting, cause to depressing production performance and egg internal quality traits (Siegel 1980), therefore, adding antioxidant to diets, may be useful after force molting phase (Skrivan et al, 2010). The aim of this study was to evaluate the effect of different levels of tomato pulp in post molted laying hens on egg production performance and egg internal quality traits during different storage times and temperatures.
Material and methods One hundred and twenty W-36 White leghorn laying hens in post-molting phase (78 week) were assigned to 3 treatments with 5 replications and 8 birds each based on completely randomized design. Some dried tomato pulps were obtained from a commercial tomato processor in West Azarbaijan province. After chemical analysis of dry matter, crude protein, crude fiber and also determining TMEn of tomato pulp, three isocaloric and isonitrogenous diets formulated to have 0, 7.5 and 15 % of tomato pulp and fed to birds for 8 weeks. Egg production, egg weight, feed consumption, egg mass and feed conversion ratio were recorded weekly and reported as monthly or total period. Six egg samples from each replicates of control group and group having best production performance (15 % tomato pulp) collected and stored in different temperatures (4 and 27° C) and duration times (1 day, 1 week and 1 month after production) then evaluated for their internal quality traits such as albumen pH, Haugh unit and yolk index.
Results and discussion Results showed that using tomato pulp up to 15 % of diet could not affect egg production of post-molted hens during 8 weeks of production (P>0.05). Similar findings have been reported by Calislar and Uygu (2010), who used up to 20 % tomato pulp in layers diet, but reported no significant effect on egg production performance, but some researchers (Jafari et al, 2006) reported decrease in egg production performance of birds fed 15% tomato pulp. In agreement with Salajegheh et al. (2012), egg weight, egg mass, feed intake and feed conversion ratio of hens were not affected significantly by use of tomato pulp up to 15 % in diet. Results of egg quality traits during different times and temperatures showed that main effects of usage levels and storage duration times were significant (P It is possible to use 15 % tomato pulp in post-molting diets of layer hens with no significant adverse effects on production performance and due to significant interaction effect of tomato pulp usage level and duration time on albumen pH and Haugh unit, the use of 15 % tomato pulp could restrict fluctuations of egg internal quality traits during storage.