Effect of In ovo Injection of Tomato Extract on Sex Differentiation and Gonadal Structure of Broiler Chicks and Their Performance

   In-ovo injection of anti-aromatase compounds have been taken into consideration by researchers in order to achieve a higher male to female sex ratio, higher economic impact, higher growth rates and better feed conversion ratio in broiler industry.  This research was conducted to find out if in ovo injection of aqueous and alcoholic extract of tomato can affect sex differentiation, sex ratio, hatchability, and performance of broiler chickens Therefore, 600 fertilized eggs were divided into 6 treatments, each with 4 replicates and 25 eggs per each replicate. Treatments included in ovo injection of tomato aqueous extract on the levels of 0.3 and 0.6 mL (TWE0.3, TWE0.6), tomato alcoholic extract on the same levels (TAE0.3, TAE0.6), in ovo injection of 0.1 mL of saline (Sham group: SG), and control group without any injection (Cont). On day 5 of incubation, the eggs were injected at the narrow end of the eggs using 1mL-syringes. Hatched chicks were reared (separated-sex) for 6 weeks to evaluate their general performances. Complete randomized block design was used and data analysis was performed using SAS software. The results showed that injection of 0.3 ml of alcoholic extract and 0.6 ml of aqueous extract lead to a significant increase in male chicken percentage at hatching compared to control group (P <0.05), without any negative effect on hatchability and performance (P >0.05). Data obtained from rearing period revealed significant improvement in some performance parameters such as average daily gain and average daily feed intake (P< 0.05). In conclusion, in ovo administration of tomato extract which contains flavonoids with anti-aromatase properties, caused higher percentage of male chicks followed by higher profit achievement. However, for more precise statement, there should be more tissue samples for histological studies and more diverse doses of tomato extracts as compounds containing anti-aromatase substances.