Author/Authors :
Shirzadegan، k نويسنده 1 Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran , , Nickkhah، i نويسنده 2 Department of Animal Science, Faculty of Agriculture, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran , , Jafari، m.a نويسنده 2 Department of Animal Science, Faculty of Agriculture, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran ,
Abstract :
The present study evaluated effects of 0.0%, 0.5%, 0.75% and 1.0% L-threonine in diet on performance and gastrointestinal tract development in broiler chickens during summer. From 0 to 42 days old, body weight gain was greater in 0.75% L-threonine fed birds than in 0.0% and 0.5% L-threonine fed birds (P < 0.05). Moreover, in jejunum and ileum both the 0.75% and 1.0% L-threonine intake caused longer villus height as compared to 0.0% and 0.5% L-threonine (P < 0.05), but no other morphological parameters were affected by L-threonine supplementation (P > 0.05). No significant differences were observed between the treatments for feed intake and feed conversion ratio during the starter, grower or whole experimental period (P > 0.05). During the growth period, 0.75% L-threonine fed birds had the highest body weight gain (P < 0.05). Carcass traits were not affected by treatments (P > 0.05). In conclusion, supplementation of 0.75% L-threonine im-proved the intestinal morphology and body weight gain of broilers under hot conditions. As well as, the higher levels of L-threonine (1.0) percent in diet can will increased the villus height in the jejunum and ileum.
