Heat stress can disrupt the balance between the heat poultry release into the environment and the heat they generate. Pequi oil has antioxidant properties, which may mitigate the heat stress effects. This study aimed to investigate the response of laying hens to pequi oil supplementation under heat stress using a proteomic approach. A total of 96 Lohmann White laying hens with 26 weeks old were housed in a completely randomized design with a 2 × 2 factorial arrangement. They were housed in two climate chambers, thermal comfort temperature ± 24.04 °C with the relative humidity ± 66.35 and heat stress (HS) ± 31.26 °C with the relative humidity ± 60.62. They were fed two diets: a control diet (CON), basal diet (BD) without additives, and with Pequi oil (PO), BD + 0.6% PO. After 84 days, plasma samples were analyzed using Shotgun and LC-MS/MS. Proteins related to anti-inflammation, transport, and the immune system were differentially expressed in hens fed PO and CON under heat stress compared to those in thermoneutral environments. This helps protect against oxidative stress and may support the body’s ability to manage heat-induced damage, stabilizing protein expression under stress conditions. The ovotransferrin proteins, fibrinogen isoforms, apolipoprotein A-I, Proteasome activator subunit 4, Transthyretin, and the enzyme serine Peptidase Inhibitor_Kazal Type 5, which presented Upregulated (Up) equal to 1, present characteristics that may be crucial for enhancing the adaptive responses of hens to thermal stress, thereby increasing their tolerance and minimizing the negative effects of heat on egg production. The data presented in this manuscript provides new insights into the plasma proteome alterations of laying hens fed a diet supplemented with pequi oil during heat stress challenges.

This paper reports the results of a mercury (Hg) and selenium (Se) metallomic study in the liver tissues of Psectrogaster amazonica and Raphiodon vulpinus from the Brazilian Amazon. Two-dimensional electrophoresis, graphite furnace atomic absorption spectrometry, and liquid chromatography-tandem mass spectrometry were performed. Hg and Se determinations allowed the calculation of Hg:Se and Se:Hg molar ratio and Se values for health benefits (Se HBVs). The Se:Hg values were >1 for both fish species, whereas the Se HBVs were >5 for P. amazonica and >10 for R. vulpinus, indicating that both possess Se reserves to control Hg toxicity. The metallomic data allowed the identification of 11 Hg/Se-associated protein spots in the two fish species, with concentrations in the range of 9.70 ± 0.14 and 28.44 ± 0.31 mg kg⁻¹ of Hg and 16.15 ± 0.21 and 43.12 ± 0.51 mg kg⁻¹ of Se. Five metal binding proteins (MBP) in the Hg/Se-associated protein spots in the liver proteome of P. amazonica and eight in R. vulpinus were identified, indicating the possible formation of Hg/Se complexes on the MBP structures. The activities analysis of catalase, superoxide dismutase, GPx enzymes, and lipoperoxide concentrations demonstrated that Hg-induced oxidative stress did not occur, possibly because both fish species possess Se reserves necessary to inhibit the Hg’s deleterious effects.

Due to its antioxidant and immunomodulatory properties, using passion fruit seed oil (PFSO) is a promising strategy to mitigate the effects of heat stress in laying hens, potentially optimizing the absorption of essential minerals such as selenium (Se) and zinc (Zn). Therefore, this study investigated the profile of selenium- and zinc-binding proteins (Se/Zn-BPs) in the hepatic proteome of Lohmann White laying hens (26 weeks old, n = 96) subjected to heat stress and whose diet was supplemented with 0.9% PFSO, using a metalloproteomic approach that combined two-dimensional electrophoresis (2D PAGE), graphite furnace atomic absorption spectrometry (GFAAS), and liquid chromatography–tandem mass spectrometry (LC-MS/MS). The experimental design was a 2 × 2 factorial (temperature: thermoneutral/stress × diet: control/PFSO) design. After 84 days, liver samples were collected and subjected to metalloproteomic analyses. GFAAS analysis showed higher concentrations of Zn and Se in the protein pellets and in 11 specific protein spots of the supplemented groups (thermoneutral/PFSO and stress/PFSO). LC-MS/MS analysis identified 56 Se/Zn-BPs, with a predominance of heat shock chaperones (HSPs) and proteins involved in energy metabolism. In conclusion, PFSO supplementation modulates Se and Zn absorption, promoting a mineral balance that optimizes immune and antioxidant defense processes. This mechanism can lead to a positive impact on the health and productive performance of laying hens under heat stress.

The chapter reports the use of metalloproteomics strategies to identify the protein abundance in muscle tissue of Psectrogaster amazonica and Raphiodon vulpinus from Madeira River/Brazil exposed to mercury (Hg), with the aim of investigating possible Hg:Se interactions. Metalloproteomic results allowed the calculation of selenium values for health benefits (SeHBVs) that showed positive values for both fish species, suggesting that fish have Se reserves in their muscle tissue necessary to control the Hg toxic effects. Protein abundance analysis (PAA) showed that the few proteins and/or enzymes with up- and/or downregulated expression were expressed in the groups with higher Hg and Se concentrations. Therefore, it can be inferred that Se could be attenuating the Hg negative action on the functions of these proteins and/or enzymes through the formation of Se-Hg complexes in the structures of these macromolecules. The catalase, glutathione peroxidase and superoxide dismutase activity analysis, as well as that of lipoperoxides concentration, did not indicate that Hg concentrations present in muscle tissue of both fish species could trigger an oxidative stress state, corroborating with PAA results. The preliminary results obtained in the present chapter provide new insights into studies of the Se mitigating effect on the Hg toxicity in fish.