ABSTRACT
Thermal stress is a risk that threatens poultry welfare and productivity. Thermal manipulation during egg incubation is considered a prevention strategy used to mitigate the detrimental effects of high ambient temperatures on birds. This study aimed to investigate the impact of thermal manipulation, applied to chicken breeder's eggs during the incubation period, on embryonic development, hatching characteristics, and chick quality, as well as posthatch thermotolerance and performance. A total of 1,200 fertile eggs were randomly and equally assigned into 2 groups of 3 replicates (200 eggs/replicate), using a randomized experimental design followed by t test. The first group eggs (G1) were subjected to a commercial setter temperature of 37.5°C with 55% relative humidity (RH) throughout the incubation period (1-18 d) and served as a control, while the second group eggs (G2) were treated the same commercial setter conditions until the 11th day of the incubation, then the eggs were exposed to a higher temperature of 39.5°C with 60% RH for 4 h daily from the 12th to the 18th day of incubation. All eggs in both groups were exposed to the same temperature condition of 37.2°C with 70% RH from the 19th to the 22nd days of the incubation (hatching period). Three hundred hatched female chicks per each treatment group were transferred into a closed-system house and distributed randomly into 20 floor pens (15 birds per pen). At the 8th week of age, birds were exposed to a daily heat challenge by raising the temperature to 35°C for 6 h until the 18th week of the chick's age. According to the results, thermal manipulation at 12 to 18 d of egg incubation positively (P ≤ 0.05) affected several studied traits. It improved some embryonic development traits, such as embryonic weight and tibia length, as well as some hatching parameters, such as hatching time and pipped eggs. It also improved hatched chick quality traits, including the chick's weight, length, and activity. In addition, it enhanced the posthatch chick's thermotolerance and body weight. Hatched chicks of G2 had significantly (P ≤ 0.05) higher total protein, albumin, IgM, glucose, calcium, total antioxidant, and T3 than G1 chicks. They also had significantly (P = 0.001) higher body weight (23%) at the 18th week of age than G1, as well as a lower feed conversion ratio (20.71%) than G1 chicks at 8 to 18 wk of age. Therefore, it is recommended to apply thermal manipulation during egg incubation, particularly at 12 to 18 d, for its positive effects on the pre- and posthatch performance.
Subject(s)
Chickens , Hot Temperature , Animals , Female , Ovum , Embryonic Development , Body WeightABSTRACT
Concurrent sonolysis of iron pentacarbonyl and poly(ethylene glycol)-400 (PEG-400) in hexadecane solvent proceeds via zero-order kinetics and results in Fe nanoparticles encapsulated in PEG-400 (Fe-PEG). The transmission electron microscopy images show Fe-PEG consisting of <3 nm Fe particles that are evenly dispersed in the PEG matrix. Mössbauer and X-ray absorption fine structure/X-ray absorption near-edge structure data reveal an ordered PEG assembly that helps protect the zerovalent Fe core. The Fe nanoparticles in Fe-PEG are superparamagnetic with a magnetization value of 45 emu/g-Fe at 10 KOe. The rheology of the synthesized material shows an unusual increase in viscosity with temperature that is likely due to lower critical saturation temperature phase segregation over 40 degrees C. The low-temperature mobility of the PEG-400 moiety in Fe-PEG would allow facile ligation of the Fe0 core with biologically and chemically active groups.
