Growth and muscle weight of bird and mammals depends on several factors such as; prenatal muscle development and postnatal growth. During embryogenesis, the numbers of muscle fibers keep on increasing and stop shortly after hatch/birth. Further muscle growth was mainly due to the increase in its fiber length and diameter1.
Previously in a study it was demonstrated that thermal conditioning (TC) of chick embryos enhanced myo-blast proliferation in post-hatching chicks. Therefore, incubation temperature proficiently affects not only the embryonic and the hatchability traits, but also the post-hatch growth and performance of chicks1.
In an another study, researchers compared optimal incubation conditions of chicks, they delivered from TC eggs during embryogenesis had significantly higher live body weight, body weight gain and better feed conversion ratio at hatch and all ages.
Manipulating the incubation temperature, particularly during the late stage of embryonic development can strongly affect the performance of hatching chicks at later ages. Most studies evaluated the effect of thermal conditioning on pre-hatching and post-hatching experiments independently of each other.
Therefore, the definite effectiveness of each of these protocols remains unknown. So a new study established whether a combination of pre- and post-hatching thermal conditioning may offer further benefits regarding either productive performance or related metabolic hormones2.
A total of 510 hatching broiler breeder eggs were obtained. Data on growth performance, metabolic hormone concentrations and histo-morphometric measurements of the myocytes of the pectoral muscles were analyzed.
The results showed that all the TC groups, especially T1T1 had higher (p<0.01) growth and carcass performance than the non TC group (T0T0). With pre- and postnatal TC, whether separately or in combination, the IGF-I level was increased, T4 was reduced, while the T3 level did not change significantly at 42 days. Moreover, the major pectoralis muscles of T1T0 and T1T1 chicks possessed greater number and histometric measurements of myocytes compared to those of the other groups.
I was accomplished that pre and/or postnatal TC treatments are a practical application to enhance productive performance and muscle growth of broiler chicks. Moreover, superior benefit could be achieved by the combination of procedures, pre and post-hatch thermal conditioning as established for the T1T1 group.
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23 August, 2019