Research On Animal Production

This study was conducted to consider the effect of theophylline in laying and some of egg characteristics on laying hens. Commercial egg type Hy-Line hens were used in a completely randomize design with 4 treatments and 3 replicates for 50 days period. The levels of different theophylline supplements (treatment) were 0 (control), one, three, and five mg per kg of body weight for 50 days. The average data were compared by using Tukey–Kramer multiple comparison tests. All levels of theophylline significantly increased laying performance. The best laying performance was observed in 3 mg/kg of theophylline. The best effect on egg size, weight, yolk and albumen height was found in hens receiving highest concentration of theophylline (p≤ 0.05). All levels of theophylline significantly decreased yolk color index (p≤ 0.05). The lowest yolk diameter was observed in 3 mg/kg theophylline. The highest albumen Haugh unit was in 1 mg/kg theophylline (p≤ 0.05). Results showed that theophylline increased the rate of laying and some of egg characteristics in hens. The best laying performance was showed in 3 mg/kg and the highest egg weight and size in 5 mg/kg of body weight theophylline.