Yolk vitamin E positively affects prenatal growth but not oxidative status in yellow-legged gull embryos

Effect of Hydrogen Oxide-Induced Oxidative Stress on Bone Formation in the Early Embryonic Development Stage of Chicken

The current study aimed to monitor the impact of H₂O₂-induced oxidative stress on avian bone formation during the early stage of embryonic development. Fertilized Cobb broiler eggs were divided into five treatment groups and micro-injected with varying concentrations of H₂O₂, i.e., control (PBS; 0 nM), 10 nM, 30 nM, 100 nM, and 300 nM, on embryonic day 3, with continued incubation thereafter. The treatment concentrations were selected based on the level of lipid peroxidation and the survival rate of embryo. Embryos were collected at 6 h, 24 h, 48 h, and 72 h post-injection. The mRNA expression levels of apoptotic markers, antioxidant enzymes, and early bone formation gene markers were measured. The results showed that the microinjection of H₂O₂ altered the expression pattern of antioxidant enzymes' mRNA during early embryogenesis and decreased the expression of COL1A2 and COL2A1 at 6 h and 24 h post-injection. Decreased expression of BMP, BGLAP, and RUNX2 was observed 48 h post-injection. Additionally, a shorter embryo length was observed in the 100 nM and 300 nM H₂O₂ treatment groups 72 h post-injection. In conclusion, H₂O₂-induced oxidative stress suppressed the expression of bone formation gene markers, with chronic effects on avian embryonic development.

Effects of in ovo feeding of vitamin E or vitamin C on egg hatchability, performance, carcass traits and immunity in broiler chickens

The effect of in ovo feeding of different levels of vitamins C and E on egg hatchability, immune response, growth and carcass traits of broiler chickens were investigated. A total of 672 fertilized eggs were assigned to one of eight experimental groups having three replicates with 28 eggs as follows: (1) negative control (not injected); (2) positive control (injected with 0.2 mL deionized water); (3) vitamin C at 1 mg; (4) vitamin C at 3 mg; (5) vitamin C at 6 mg; (6) vitamin E at 0.5 IU; (7) vitamin E at 0.75 IU; and (8) vitamin E at 1.0 IU. At the end of incubation, the number of chicks hatched, and their individual body weight were recorded. Among hatched birds, a total of 240 mixed chicks were randomly selected (30 subject per group equally shared in three pen floors). Chicks were vaccinated against Avian Influenza, Gumboro, Bronchitis, and Newcastle disease virus. Performance parameters were weekly evaluated until 42 days of age. At days 28 and 42, broiler serum and spleen and Bursa of Fabricius relative weight were assessed as well as on day 42 the carcass traits. From results, in ovo injection with 3 mg of vitamin C or 0.75 IU of vitamin E, increased significantly (p < .05) the embryos hatchability when compared to the negative control. However, body weight at hatch and growth performance parameters showed no differences among treatments. Similarly, in ovo concentrations of vitamins C or E showed no differences on carcass traits, immunity-related organs weight or immune response for anti-Newcastle disease hemagglutination-inhibition and total immunoglobulins against sheep red blood cells (SRBC) when compared to the control groups. Based on findings, it can be concluded that in ovo feeding vitamins E and C supported positively chicken embryos hatchability demonstrating the key-role as antioxidant agents; however, further studies are currently being evaluated.

Spatio-temporal variation in oxidative status regulation in a small mammal

Life-history allocation trade-offs are dynamic over time and space according to the ecological and demographical context. Fluctuations in food availability can affect physiological trade-offs like oxidative status regulation, reflecting the balance between pro-oxidant production and antioxidant capacity. Monitoring the spatio-temporal stability of oxidative status in natural settings may help understanding its importance in ecological and evolutionary processes. However, few studies have yet conducted such procedures in wild populations. Here, we monitored individual oxidative status in a wild eastern chipmunk (Tamias striatus) population across the 2017 summer active period and over three study sites. Oxidative damage (MDA: Malondialdehyde levels) and non-enzymatic antioxidant levels (FRAP: Ferric reducing antioxidant power and HASC: Hypochlorous acid shock capacity) were quantified across time and space using assays optimized for small blood volumes. Our results showed an increase in oxidative damage mirrored by a decrease in FRAP throughout the season. We also found different antioxidant levels among our three study sites for both markers. Our results also revealed the effects of sex and body mass on oxidative status. Early in the active season, females and individuals with a greater body mass had higher oxidative damage. Males had higher HASC levels than females throughout the summer. This study shows that oxidative status regulation is a dynamic process that requires a detailed spatial and temporal monitoring to yield a complete picture of possible trade-offs between pro-oxidant production and antioxidant capacity.

Prenatal independent and combined effects of yolk vitamin E and corticosterone on embryo growth and oxidative status in the yellow-legged gull

Variation in the concentration of antioxidants and hormones of maternal origin in the eggs of birds can have a profound influence on offspring phenotype both prenatally and postnatally. Egg maternal substances can have interacting effects, but experimental studies of the consequences of the combined variation in the egg concentration of such molecules are extremely rare, particularly as far as prenatal stages are concerned. We manipulated the yolk concentration of vitamin E and corticosterone, which are, respectively, the main antioxidant and the main glucocorticoid hormone in bird eggs, both independently and simultaneously, and we tested their separate and combined effects on growth and oxidative status in the liver and in the brain of yellow-legged gull (Larus michahellis) embryos. Egg supplementation of relatively large physiological doses of corticosterone depressed embryo growth (total body mass, tarsus length and liver mass), whereas administration of vitamin E in association with corticosterone restored normal growth. Vitamin E did not affect embryo growth when administered alone. We further analysed the independent and combined effects of vitamin E and corticosterone on liver and brain total antioxidant capacity, the concentration of reactive oxygen molecules and lipid peroxidation. Vitamin E significantly reduced liver total antioxidant capacity, while corticosterone depressed brain lipid peroxidation. Prenatal exposure to vitamin E and corticosterone appears to have antagonistic effects on body growth, although vitamin E is not limiting in yellow-legged gull eggs. In combination with the results of previous experiments on the same species applying smaller experimental doses or focusing on the postnatal rather than prenatal life stages, our findings indicate that the effects of a physiological increase in the egg concentration of these substances can be life stage and dose specific, implying that generalizing prenatal effects of egg compounds may not be feasible.