Physiological and biochemical effects of two feed antioxidants in modeling technological stress in pigs (Sus scrofa domesticus Erxleben, 1777)

Intensive livestock technologies do not fit well with the physiology of domestic species and put farm animals at risk of various health problems and disorders, which most negatively affects highly productive animals with intensive metabolism. Feed antioxidants might be a solution to improve productive health, adaptive capabilities and stress resistance of livestock. The outcome of adaptogen application depends on thorough elucidation of mechanisms of their action on physiological and biochemical processes in the body compromised by stress. Our study imitated social stress (modeled stress, MS) as the most common in intensive livestock to compare two dietary antioxidant additives of different origin and chemical composition. Thirty-six hybrid boars F2 (Large White × Landrace) × Duroc aged 103 days (35 kg live weight) were assigned for four treatments (9 animals per each): 1 - control without MS, 2 - control with MS, 3 - MS + proteinate Se (PSe) (B-TRAXIM Selenium-11, PANCOSMA CANADA, Inc.; 0.2 mg a.i. per 1 kg feed), and 4 - MS + dihydroquercetin (DHQ) Ekostimul-2 drug (ООО Ametic, Russia; 32 mg a.i. per 1 kg feed). To simulate social stress, boars were moved every 14 days within the group to change the neighbors. Blood for assay was sampled three times over the trial from five boars of each group. With age, the blood cortisol level was revealed first to decrease by 36.8. 22.5, 41.3 and 52.8 % from the initial values in groups 1, 2, 3 and 4, respectively, though by the end of the final feeding there was a 46.4; 37.4; 8.1 and 60.4 % increase in the parameter. The cortisol concentration was the highest in group 3 (MS + PSe) during intensive growth (282 nmol/l vs. 211 and 214 nmol/l for groups 1 and 2). In groups 1, 2 (MS), and 3 (MS + PSe), the cortisol concentration reached 309, 294 and 305 nmol/l by the end of feeding. Blood cortisol level was the lowest in group 4 (+ DHQ), 134 nmol/l (p = 0.07 compared to group 2) at intensive growth and 215 nmol/l at final fattening, corresponding with TBK AP levels which were also 6.7 and 12.3 % lower, respectively. Lactate dehydrogenase (LDH) activity and creatine phosphokinase (CPK) activity also altered. In group 1, LDH activity decreased from 459.4 to 377.5 IU/l over the trial. The same pattern was characteristic of group 4 (MS + DHQ). In group 2 (MS) and group 3 (MS + PSe), LDH activity declined to 317.0 and 289.3 IU/l by the end of feeding, which was 16.0 (p 0.05) which indicate a balanced animal diet, changes were noted that characterize the effect of the adaptogens under MS. In groups 2-4, blood phosphorus concentration was higher than in control group 1, 4.42 (p = 0.07), 4.52 (p = 0.1) and 4.64 mmol/l (p 2 (Large White ½ Landrace) ½ Duroc. As a result, over the entire period of the trial, groups 1, 2, 3, and 4 showed an average increase of 1047, 1035, 1003 and 1042 g, respectively, of which the weight gain was the greatest in control 1 (without stress) and in group 4 fed DHQ at MS. Thus, our findings give grounds for further studying effects of these feed adaptogens for their proper use in intensive industrial pig breeding.