20 آذر 1403
عنايت رحمت نژاد

عنایت رحمت نژاد

مرتبه علمی: استادیار
نشانی: دانشکده مهندسی کشاورزی - گروه مهندسی علوم دامی
تحصیلات: دکترای تخصصی / تغذیه طیور
تلفن: -
دانشکده: دانشکده مهندسی کشاورزی

مشخصات پژوهش

عنوان Embryonic thermal manipulation and post-hatch dietary guanidinoacetic acid supplementation alleviated chronic heat stress impact on broiler chickens
نوع پژوهش مقالات در نشریات
کلیدواژه‌ها
broiler, guanidinoacetic acid, heat stress, thermal manipulation
مجله JOURNAL OF THERMAL BIOLOGY
شناسه DOI https://doi.org/10.1016/j.jtherbio.2024.103976
پژوهشگران غلامرضا زابلی (نفر اول) ، عنایت رحمت نژاد (نفر دوم)

چکیده

The study investigated the effects of embryonic thermal manipulation (TM) and post-hatch guanidinoacetic acid (GAA) supplementation on male broiler chickens exposed to chronic heat stress (HS). Ross 308 eggs (n = 710) were randomly assigned to control (37.8°C, 56% RH) or TM (39.5°C, 65% RH for 12 hours/day from embryonic day 7 to 16) treatments. After hatching, chicks were further assigned to four dietary treatments (n = 12 birds/pen, 5 replicates/treatment): control, control with 1.2 g/kg GAA supplementation (CS), TM, and TM with 1.2 g/kg GAA supplementation (TMS). All birds were subjected to chronic HS (32-36°C, 6 hours/day, 55% RH) from day 28 to 42. Embryonic TM treatment decreased hatchability, hatching weight (HW), and facial temperature (FT). During the pre-HS period (days 1-28), no significant differences in feed conversion ratio (FCR) and mortality were observed, although the TM group exhibited the lowest body weight gain (BWG). Following HS exposure (days 29-42), the TMS group displayed significantly higher BWG than the control and CS groups. The TM and TMS groups also demonstrated significantly lower FCR and mortality rates during this period. Across the entire period (days 1-42), BWG was significantly higher in the TMS group compared to other groups. Furthermore, TM and TMS treatments were associated with lower mortality rates, improved FCR, better European Performance Efficiency Index (EPEI), and reduced abdominal fat deposition. The experimental treatments did not significantly affect intestinal morphology or most blood parameters, except triiodothyronine (T3), thyroxine (T4), and uric acid. Plasma concentrations of T3, T4, and uric acid were significantly lower in the TM and TMS groups compared to the control and CS treatments. The findings suggest that a combined strategy of embryonic TM and post-hatch dietary GAA supplementation may not only alleviate the detrimental effects of HS but also promote beneficial physiological responses in broiler chicke