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The impact of Zearalenone on heat-stressed skeletal muscle in pigs

2022; Oxford University Press; Volume: 100; Issue: 8 Linguagem: Inglês

10.1093/jas/skac215

1544-7847

Tori E. Rudolph, Crystal M Roach, L.H. Baumgard, Jason W Ross, Aileen F. Keating, Josh T Selsby,

Exercise and Physiological Responses

Heat stress (HS) and Zearalenone (ZEN) exposure affect growth, production efficiency, and animal welfare; and, under extreme situations, both can be lethal. Given that both HS and ZEN independently cause oxidative stress, we hypothesized that simultaneous exposure to HS and ZEN would cause greater oxidative stress in porcine skeletal muscle than either condition, alone. To address this hypothesis, crossbred, prepubertal gilts were treated with either vehicle control (cookie dough) or ZEN (40 μg/kg) and exposed to either thermoneutral (TN; 21.0 °C) or 12-h diurnal HS conditions (night: 32.2 °C; day: 35.0 °C) for 7 d. Pigs were euthanized immediately following the environmental challenge and the glycolytic (STW) and oxidative (STR) portions of the semitendinosus muscle were collected for analysis. In STR, malondialdehyde (MDA) concentration, a marker of oxidative stress, tended to increase following ZEN exposure (P = 0.08). HS increased CAT (P = 0.019) and SOD1 (P = 0.049) protein abundance, while ZEN decreased GPX1 protein abundance (P = 0.064) and activity (P = 0.036). In STR, HS did not alter protein expression of HSP27, HSP70, or HSP90. Conversely, in STW, MDA-modified proteins remained similar between all groups. Consistent with STR, ZEN decreased GPX1 (P = 0.046) protein abundance in STW. In STW, ZEN decreased protein abundance of HSP27 (P = 0.032) and pHSP27 (P = 0.0068), while HS increased protein expression of HSP70 (P = 0.04) and HSP90 (P = 0.041). These data suggest a muscle fiber type-specific response to HS or ZEN exposure, potentially rendering STR more susceptible to HS- and/or ZEN-induced oxidative stress, however, the combination of HS and ZEN did not augment oxidative stress.Heat stress (HS) and Zearalenone (ZEN), a toxic feed contaminant, affect growth, production efficiency, and animal welfare, and can cause death. As HS and ZEN independently increase oxidative stress, an imbalance of free radical production and clearance, and the likelihood of ZEN contamination during heat events, we hypothesized concomitant exposure would induce oxidative stress in pig skeletal muscle more than either agent alone. To address this, female pigs were treated with a placebo or low dose of ZEN and exposed to ambient temperature or a mild cyclic HS designed to mimic environmental conditions (hot days, cooler nights) for 7 d. Following these treatments, fast- and slow-twitch muscles were collected for analysis. In slow-twitch muscle, we observed increased markers of oxidative stress in pigs exposed to ZEN primarily driven by HS and ZEN treated pigs. Additionally, ZEN reduced antioxidant abundance and enzymatic activity regardless of the environment. Conversely, HS and/or ZEN did not cause oxidative stress in fast-twitch muscle, although ZEN altered antioxidant abundance. Although a mild HS and ZEN dose was used, oxidative stress markers were altered, suggesting that slow-twitch muscle is susceptible to HS- and ZEN-mediated changes. These data raise the possibility that more severe HS exposures and higher ZEN doses may compromise muscle health.