A similar effect was confirmed by with TM at 39.5☌ for 12 h/d from E7 to E16. reported that TM at 39.5☌ for 3 hours (h)/day (d) from embryonic age (E) E11–E16 improves the chicks’ thermotolerance acquisition. Earlier studies laid the foundation for implementation of TM between different days of embryogenesis in addition to key factors such as duration and strength of TM to enhance the chick’s ability to cope with environmental challenges of cold and heat stress during post-hatch period. TM (i.e., increasing or lowering incubation temperature) and broiler chicken embryogenesis has been deeply studied by Collin A, Tzschentke B, Piestun Y, Yahav S, and Halevy O, and the technique enhances chick quality through improved body weight gain, increased expression of genes in the breast muscle, and thermotolerance. Incubation temperature is the most significant incubation condition and there has been an increase in studies regarding thermal manipulation (TM). In addition, while the first quarter of incubation is critical to chicken embryogenesis, the last quarter is very significant to hatch and post hatch performance. Incubation conditions have a significant effect on hatchability, chick quality and post-hatch performance in chicken. Thus, manipulation of different incubation conditions to meet the requirements of modern broiler genotypes is under continuous investigation. A possible reason is that the newly developed broiler genotypes have diverged considerably compared to traditional genotypes in terms of the biological, physiological, and biochemical requirements. Therefore, during incubation, new techniques which are associated with embryo management are increasing with this demand. In recent decades, the need to increase hatchery efficacy is increasing with demand for quality chicks. In conclusion, the results of TM studies on embryogenesis, hatchability and hatching quality of broiler chicks are still contradicting, which is a possible limitation for its commercial use. TM above 39.5☌ significantly increases and decreases embryo mortality and hatchability, respectively compared with standard incubation temperature. In addition, high temperature TM (38.5–39.5☌) between E7 and E18 has no significant effect on embryo mortality, hatchability, and chick quality compared to standard incubation temperature (37.8☌). The moderate elevation in incubation temperature (38.5–39.5☌) intermittently (3–18 h/d) between E07 and E18 improves the chick’s thermoregulation capacity and reduces any adverse effect of TM on hatchability, and chick quality (e.g., hatch weight and chick length) compared with continuous TM.
It is evidenced that during TM, key considerations include duration and strength of TM besides stage of embryonic development. Publications written in English between 2015 and September 2021 were considered. The search and selection of eligible publications was through databases web of science, PubMed, and Scopus. Here, PRISMA guidelines were utilized to systematically evaluate the publications reporting the effect of thermal manipulation during embryogenesis on incubation performance, hatchability, and hatching quality of broiler chicks.
0 kommentar(er)
