Marek Szczubiał
Studies on the oxidative-antioxidative status during periparturient period in sows in aspect of the of MMA syndrome

One of the elements of the organism homeostasis essential for the proper course of the physiological processes is the balance between the pro- and antioxidative processes. This balance disturbance leading to the prevalence of the oxidation processes and production of excessive reactive oxygen species (ROS) quantity induces the oxidative stress and makes a threat to organism. It is connected with the etiopathogenesis and the run of numerous diseases in man and animal. There are some premises implying that the oxidative stress also contributes to the development of the periparturient period disorders. The most frequent disease of this period in sows proves to be the MMA syndrome that causes substantial economic losses. Although this disease has been recognized for a long time, neither its etiology is known to the full nor effective prophylaxis worked out. The available literature gives scarce information on the behaviour of the antioxidative protection elements in sows at the periparturient period and potential oxidative stress participation in the MMA syndrom etiopathogenesis.
The studies performed in two stages were designed to:
a) determine the development of the antioxidative defence parameters and the oxidative stress indices in sows at the appropriate course of the periparturient period,
b) establish the effect of disturbances of the pro- and antioxidative balance over the periparturient period on the MMA syndrome occurrence,
c) define the influence of supplementation with some antioxidants administered to the pregnant sows on their oxidative protection status and the appearance of the oxidative stress during the periparturient period as well as MMA syndrome occurrence.
At the first research stage some parameters of the antioxidative defence and the oxidative stress indices in the course of the appropriate and disturbed with MMA syndrome periparturient period in sows were characterized. The examinations covered 60 pigs of the following breeds: Polish Large White (PLW), Polish Landrace (PL) and PLW ‘ PL aged 1-3 years. All the animals came from one farm of the closed production cycle. The sows with the MMA symptoms recorded within 48 h after parturition constituted a group with MMA syndrome (n = 12). From the other clinically healthy animals 24 sows were chosen randomly to make a group of a proper perinatal period. The activity of the following erythrocyte antioxidative enzymes in haemolysates was determined: glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), superoxide dismutase (SOD) and catalase (CAT). The concentration of: ascorbic acid (vitamin C), vitamin E, glutathione, thiobarbituric acid reactive substances (TBARS), SH-groups, bityrosine and formylokinurenine in blood plasma was evaluated. In blood serum a concentration of selenium (Se), zinc (Zn) and copper (Cu) was determined. Analysing the results of the antioxidative enzyme activity determinations in erythrocytes of the studied sows it was proved that in both, healthy animals and those with MMA syndrome there was recorded a significant increase of activity 24-48 h prior to delivery. After the parturition in a sow group with MMA syndrome there was noted a further significant rise of GSH-Px and SOD along with the CAT activity fall. In this group of animals before and after the parturition, statistically significant lower activity of GSH-Px, GSH-Tr and CAT was detected. In the present author`s own investigations no significant differences between the studied sow groups in respect of concentration of selenium, zinc and copper in blood serum were recorded.
The studies performed showed a significant decrease of vitamin C in blood plasma after the parturition. In the sows with the MMA syndrome detected prior to the parturition and immediately after it, the vitamin C concentration was significantly lower. The vitamin E concentration in the plasma of the examined sows got lowered as the delivery date approached. Starting with the last 24-48 h before the parturition up to 13-14 days after it, the vitamin E concentration was lower in the group with the MMA syndrome compared to the healthy animals. On 6-7 day and 13-14 day following the parturition the differences became statistically significant. Alike, a glutathione concentration in blood plasma in the sows affected by the MMA syndrome was significantly lower throughout most of the perinatal period as against the healthy animals. In both groups the lowest values of glutathione concentration were recorded 24-48 h before the parturition and 24-48 h after it.
The studies revealed that 24-48 h prior to delivery in the plasma of the examined sows a significant increase of the TBARS concentration was noted that proves the lipid peroxidation rise. At the healthy sows on 6-7 days following parturition there was detected a fall of TBARS concentration. In the group of sows with the MMA syndrome after the delivery a further increase of TBARS concentration appeared. In this sow group the TBARS concentration was significantly higher than at the healthy animals.
The obtained results of the present author`s own studies indicated a significant growth of SH-group concentration in the plasma of the examined sows in last 24-48 h preceding the parturition. A further significant SH-group concentration occurred after the delivery of the sows affected by MMA syndrome. In both sow groups an increase of bityrosine concentration in blood plasma 24-48 h prior to parturition and 24-48 h following it, was detected just like a formylokinurenine concentration 24-48 h before the delivery. A statistically significant higher concentration of bityrosine and formylokinurenine was noted in the group with the MMA syndrome.
The other stage of the research focused on the evaluation of the impact of vitamin C, vitamin E and beta-carotene supplement on the pregnant sows, their pro- and antioxidative balance at the periparturient period and the MMA syndrome occurrence. The studies covered 120 sows of the following breeds: PLW, PL and PLW ‘ PL aged 1-3 years. All the sows came from the same farm as the animals in the first stage of investigation were used. The animals were divided into two groups – experimental and control, 60 units each. The sows from the experimental group had their feed supplemented with 200 mg vitamin E and 1000 mg vitamin C (Polfamix EC, Polfa Kutno) per animal twice a week from the mid pregnancy period and on 14 and 7 day before the parturition had beta-carotene 70 mg per animal injected intramuscularly (Carofertin, Werfft-Chemie GmbH, Viena). The control group was not supplemented. A significant increase of the activity of GSH-Px, SOD and CAT in erythrocytes as well as the concentration of vitamin C and E in the plasma of the supplemented sows at the periparturient period was stated. The sows supplied with these antioxidants combination in the latter part of gestation showed a significantly lower concentration of TBARS, bityrosine and formylokinurenine in blood plasma as well as higher SH-group concentration at the periparturient period.
The improvement of the pro- and antioxidative status in the supplemented sows was accompanied by a percentage decrease of the MMA syndrome incidence.