الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 164 |  |  |
| | | from | 164 | | |
Abstract
The experiment was conducted at Physiology Department, Faculty of Veterinary Medicine, (Moshtohor), Benha University and Biotechnology lab, Faculty of Veterinary Medicine, Kafrelsheikh University.The aim of the current study was to evaluate the effects of in ovo administration of the myostatin inhibitor, myostatin pro-pepetide (Myo-Pro) gene on growth performance, carcass traits, histological changes in skeletal muscle and gene expression of some myogenic marker associated with muscle growth and development, such as IGF1, GH, MyoD, MyoG genes in Fayoumi chicken A total number of 240 fertile eggs of Fayoumi chicken were used. The chicks were randomly allocated into equally divided into 2 groups (120 per each, three replicates per group); group 1 (control ) and group2 (Myostatin-/-).The obtained results can be summarized as follows:1- All transgenic (Myostatin-/-) chicks at different time points (from hatching to 12w) have a significant (P<0.05) higher body weight than control. Males of Myostatin-/- group had significantly (p<0.05) higher body weights during the whole periods of age from 0 to 12 w than female chicks.2- Myostatin-/- chicks had a significant (p<0.05) increase in body weight gain during whole periods of age from 0 to 12 w compared with wild chicks.3- Myostatin-/- male had significantly (p<0.05) higher relative growth rate during most period of age than control group. Myostatin-/- female had significantly (p<0.05) higher relative growth rate during most weeks than control group There is no significance difference in the amount of feed intake between Myostatin-/- and control chicken. This indicates that the higher body weight in Myostatin-/- chickens is not due to higher feed consumption.4-The feed conversion ratio was significantly decreased in Myostatin-/- as compared to wildtype chicken. This indicates the higher food conversion efficiency in Myostatin-/- chickens which reflects their higher meat yield 5-To ensure that the increase in body weight is due to increase mass and growth of the muscles rather than viscera or other non-muscular tissues, carcass traits and characters were examined. The results showed a significant higher live weight, carcass weight, and meat + bones weight in Myostatin-/- chickens as compared to control chickens, with a slight higher mean in males than females. This indicates that the increase in body weight is mainly due to increase meat (skeletal muscles).6-The increased muscle mass may be due to either increase in muscle fibers numbers (hyperplasia) or increase in muscle diameters (hypertrophy). To check the both possibilities, we examined the gastrocnemius muscle fibers number and diameter (cross sectional area). The results showed that the increase in muscle mass and subsequently in meat production is due to hypertrophy rather than hyperplasia.7-The histological examination of the stained slides showed significant hypertrophy of the muscle fibers in both sex of transgenic chickens lack Myostatin (Myostatin-/-) as compared to control chickens. The cytoplasm of muscle fibers in Myostatin-/- chicken contained inclusion structure seem to be aggregation of sarcoplasmic reticulum.8-The muscles of Myostatin-/- chickens had a significant upregulated expression of some myogenic marker associated with muscle growth and development, IGF1, GH, MyoD, MyoG genes as compared to control chickens.