Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Effects of In Ovo Methionine-Cysteine Injection on Embryonic Development, Antioxidant Status, IGF-I and TLR4 Gene Expression, and Jejunum Histomorphometry in Newly Hatched Broiler Chicks Exposed to Heat Stress during Incubation.

Abstract: Sulfur amino acids are typically the first-limiting amino acids (AA) used in protein metabolism in poultry. Therefore, we hypothesized that their utilization in the pre-hatch period would affect embryonic development, IGF-I and TLR4 gene expression, antioxidant status, serum biochemical profile, and jejunum histomorphometry of newly hatched Ross broiler chicks incubated under heat stress conditions. A total of 150 fertile broiler eggs were subjected to heat stress (39.6 °C for 6 h/d) from d10 until d18 and injected at d 17.5 of incubation with methionine and cysteine (Met-Cys) at a dose of 5.90 mg l-methionine plus 3.40 mg l-cysteine. The effects of Met-Cys administration were examined and compared with the control (Non-injected group) and 0.75% NaCl injected group. The results showed that no significant differences among all groups in serum protein profiles (total protein, albumin, globulin, and albumin/globulin ratio) and creatine kinase were observed. The level of heat shock protein-90 was decreased with Met-Cys In ovo injection. The In ovo injection of Met-Cys also improved the values of total antioxidants capacity and glutathione in examined tissues. At the same time, an increase in fold change mRNA abundance of IGF-I and TLR4 was observed after Met-Cys injection in tested tissues. Finally, an increase of 29% in villus area was found after Met-Cys injection compared to the control group. In conclusion, the In ovo injection of Met-Cys resulted in improved embryonic development, IGF-I and TLR4 gene expression, antioxidant status and jejunum histomorphometry of newly hatched broiler chicks exposed to heat stress during incubation.

Incubation temperature and phenotypic traits of Sceloporus undulatus: implications for the northern limits of distribution

Abstract: Cold environmental temperature is detrimental to reproduction by oviparous squamate reptiles by prolonging incubation period, negatively affecting embryonic developmental processes, and by killing embryos in eggs directly. Because low soil temperature may prevent successful development of embryos in eggs in nests, the geographic distributions of oviparous species may be influenced by the thermal requirements of embryos. In the present study, we tested the hypothesis that low incubation temperature determines the northern distributional limit of the oviparous lizard Sceloporus undulatus. To compare the effects of incubation temperature on incubation length, egg and hatchling survival, and hatchling phenotypic traits, we incubated eggs of S. undulatus under temperature treatments that simulated the thermal environment that eggs would experience if located in nests within their geographic range at 37°N and north of the species’ present geographic range at latitudes of 44 and 42°N. After hatching, snout–vent length (SVL), mass, tail length, body condition (SVL relative to mass), locomotor performance, and growth rate were measured for each hatchling. Hatchlings were released at a field site to evaluate growth and survival under natural conditions. Incubation at temperatures simulating those of nests at 44°N prolonged incubation and resulted in hatchlings with shorter SVL relative to mass, shorter tails, shorter hind limb span, slower growth, and lower survival than hatchlings from eggs incubated at temperatures simulating those of nests at 37 and 42°N. We also evaluated the association between environmental temperature and the northern distribution of S. undulatus. We predicted that the northernmost distributional limit of S. undulatus would be associated with locations that provide the minimum heat sum (∼495 degree-days) required to complete embryonic development. Based on air and soil temperatures, the predicted northern latitudinal limit of S. undulatus would lie at ∼40.5–41.5°N. Our predicted value closely corresponds to the observed latitudinal limit in the eastern United States of ∼40°N. Our results suggest that soil temperatures at northern latitudes are not warm enough for a sufficient length of time to permit successful incubation of S. undulatus embryos. These results are consistent with the hypothesis that incubation temperature is an important factor limiting the geographic distributions of oviparous reptile species at high latitudes and elevations.

Nest attentiveness and egg temperature do not explain the variation in incubation periods in tropical birds

Abstract: The wide range in incubation periods among bird species has puzzled biologists for decades, because an extended egg-phase increases time-dependent mortality of the eggs. We investigated a recently proposed mechanistic explanation inspired by life-history theory, suggesting that adults may increase their own survival by reducing nest attentiveness, the percentage of daytime spent incubating eggs, in exchange for reduced offspring (egg) survival due to a longer incubation period. Incubation behaviour and egg temperatures (Tegg) of 14 bird species in the humid lowland tropics were studied to test the hypothesis that lower nest attentiveness and reduced Tegg cause longer incubation periods. Increased nest attentiveness correlated with higher average Tegg. However, neither nest attentiveness nor average Tegg was associated with the length of the incubation period. Longer off-bouts resulted in lower Tegg, but neither number of off-bouts nor off-bout length was associated with incubation period. In addition, we reanalysed a previously published negative association between Tegg and incubation period based on literature data from temperate passerine birds using a larger data set and found no significant correlation. In conclusion, our results do not support the hypothesis that longer incubation periods are caused by reduced nest attentiveness and corresponding lower Tegg.