Liu, F., Celi, P., Chauhan, S., Cottrell, J.J., Abrasaldo, A., Talukder, S., Leury, B.J., and Dunshea, F. (2015) Effects of heat stress and antioxidants (selenium or vitamin E) supplementation on oxidative status in growing pigs. In: Abstracts from the American Society of Animal Science and the American Dairy Science Association Midwest Branch 2015 Meeting. pp. 85-86. From: American Society of Animal Science and the American Dairy Science Association Midwest Branch 2015 Meeting, 16-18 March 2015, Des Moines, IA, USA.

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Abstract

Heat stress (HS) results in poor performance in growing pigs, and is associated with increased oxidative stress (OS) due to imbalances between free radicals production and antioxidants system. Therefore, the aims of this experiment were to investigate the effects of supplementation with antioxidants (Se and vitamin E, VE) on OS status and HS amelioration in growing pigs. Thirty-six gilts (Large White × Landrace, 28 ± 3 kg) were fed control (0.24 ppm Se, 17 IU VE/kg, NRC 2012 recommended), or control plus Se (1.0 ppm Se yeast) or VE (200 IU VE/kg) diet for 14 d, then housed in either thermoneutral (20°C, humidity 40%; TN) or HS (35°C from 0900 to 1700 h/28°C from 1700 to 0900 h, humidity 35%) conditions for 7 d. Feeding was restricted and equalized at 2.5 times of maintenance requirement. Blood samples were collected at d 1 and 7 during thermal exposure to evaluate OS by quantifying 1) derived reactive oxygen metabolites (d-ROM, Carratelli Unit/mL); 2) antioxidants markers: biological antioxidant potential (BAP, μM), oxy-absorbent capacity (OXY-abs, μM), thiols (SHp, μM), erythrocyte glutathione peroxidase activity (GPx, μmol · min–1 · mL–1 ); 3) oxidative damage marker: advanced oxidized protein products (AOPP, μM). Leukocyte HSP70, HIF-1a, GPx-1, and GPx-4 mRNA expression was quantified by real-time RT-PCR. Results were analyzed using REML in Genstat 16th with diet, temperature, and day as fixed effects, and pigs as random model. HSP70 and HIF-1a expression are the markers of hyperthermia and hypoxia, and both were up-regulated by HS (P < 0.04). However, against our expectation, free radicals production, as assessed by d-ROM decreased during HS (616 vs. 593, P = 0.04). GPx activity and SHp levels were not affected by HS, but BAP (2865 vs. 2770, P = 0.02) and OXY-abs (300 vs. 287, P = 0.03) were reduced, indicating HS compromised the antioxidant defense system. Oxidative damage occurred during HS, as evidenced by increased AOPP (24.6 vs. 32.4, P = 0.008). Selenium supplementation tended to increase GPx activity during HS (12.2, 12.4, and 15.4 for Control, VE, and Se, P = 0.07) independently of GPx gene expressions. Selenium also lowered d-ROM under TN conditions (656, 606, and 599, for Control, VE, and Se, P < 0.05), but not during HS. Overall, VE did not influence any of the parameters measured, and Se did not affect BAP, OXY-abs, or AOPP. In conclusion, HS triggered OS by compromising the antioxidant defense system, but Se or VE supplementation did not mitigate HS-induced OS, although GPx activity was improved by Se.

Item ID:	86266
Item Type:	Conference Item (Abstract / Summary)
Date Deposited:	24 Jul 2025 02:38
FoR Codes:	30 AGRICULTURAL, VETERINARY AND FOOD SCIENCES > 3003 Animal production > 300303 Animal nutrition @ 100%
SEO Codes:	10 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 1004 Livestock raising > 100410 Pigs @ 100%
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