Dietary zinc-chitosan nanoparticles addition influences on growth performance, apparent total tract digestibility, carcass indices, and immune function in weaned rabbits

Dietary Supplementation of Microalgae and/or Nanominerals Mitigate the Negative Effects of Heat Stress in Growing Rabbits

Heat stress (HS) is one of the most significant environmental factors that result in fluctuations and shrinkage in rabbit growth, health, and overall productivity. This study aims to investigate the effects of dietary mineral nanoparticles (selenium or zinc) and/or Spirulina platensis (SP) independently and in combination on stressed growing rabbits. A total of 180 weaned growing New Zealand White rabbits were included in this study and randomly divided into six dietary treatments. Rabbits received a basal diet (control group; CON group) or fortified with SP (1 g/kg diet), selenium nanoparticles (SeNPs, 50 mg/kg diet), zinc nanoparticles (ZnNPs, 100 mg/kg diet), and a mixture of SP and SeNPs (SPSeNPs) or SP and ZnNPs (SPZnNPs) groups for 8 weeks during summer conditions. The obtained results demonstrated a significant increase in the final body weight and weight gain (p < 0.05). Additionally, the feed conversion ratio was improved during the periods from 6 to 14 weeks in the treated rabbits compared to those in the CON group. Dietary supplements considerably improved (p < 0.05) the blood hematology (WBCs, Hb, RBCs, and Hct) and some carcass traits (liver weights and edible giblets). All dietary supplements significantly decreased serum levels of total glycerides (p < 0.0001), AST (p = 0.0113), ALT (p = 0.0013), creatinine (p = 0.0009), and uric acid (p = 0.0035) compared to the CON group. All treated groups (except ZnNPs) had lower values of total bilirubin and indirect bilirubin in a dose-dependent way when compared to the CON group. The values of IgA, IgG, and superoxide dismutase were significantly improved (p < 0.05) in all treated rabbits compared to the CON group. Compared with the CON group, the levels of T3 (p < 0.05) were significantly increased in all treated growing rabbits (except for the ZnNP group), while the serum cortisol, interferon-gamma (IFN-γ), malondialdehyde, and protein carbonyl were significantly decreased in the treated groups (p < 0.05). Dietary supplements sustained the changes in hepatic, renal, and cardiac impairments induced by HS in growing rabbits. Adding SP (1 g/kg diet) or SeNPs (50 mg/kg diet) in the diet, either individually or in combination, improved growth performance, blood picture, and immunity-antioxidant responses in stressed rabbits. Overall, these feed additives (SP, SeNPs, or their mixture) can be applied as an effective nutritional tool to reduce negative impacts of summer stress conditions, thereby maintaining the health status and improving the heat tolerance in growing rabbits.

Quercetin suppresses ROS production and migration by specifically targeting Rac1 activation in gliomas

P66Shc and Rac1 proteins are responsible for tumor-associated inflammation, particularly in brain tumors characterized by elevated oxidative stress and increased reactive oxygen species (ROS) production. Quercetin, a natural polyphenolic flavonoid, is a well-known redox modulator with anticancer properties. It has the capacity to cross the blood-brain barrier and, thus, could be a possible drug against brain tumors. In this study, we explored the effect of quercetin on Rac1/p66Shc-mediated tumor cell inflammation, which is the principal pathway for the generation of ROS in brain cells. Glioma cells transfected with Rac1, p66Shc, or both were treated with varying concentrations of quercetin for different time points. Quercetin significantly reduced the viability and migration of cells in an ROS-dependent manner with the concomitant inhibition of Rac1/p66Shc expression and ROS production in naïve and Rac1/p66Shc-transfected cell lines, suggestive of preventing Rac1 activation. Through molecular docking simulations, we observed that quercetin showed the best binding compared to other known Rac1 inhibitors and specifically blocked the GTP-binding site in the A-loop of Rac1 to prevent GTP binding and, thus, Rac1 activation. We conclude that quercetin exerts its anticancer effects via the modulation of Rac1-p66Shc signaling by specifically inhibiting Rac1 activation, thus restraining the production of ROS and tumor growth.