Changes of vitamins A, E, and C and lipid peroxidation status of breeding and pregnant sheep during dry seasons on medium-to-low quality forages

Abstract

This study assessed the changes of plasma vitamin A, E, and C and the lipid peroxidation status of sheep during breeding and pregnancy under drought conditions. The study was conducted on 105 cross-bred fat tailed ewes, 3-5 years old with body condition scores (BCS) of 2.5 to 3.5. The ewes were grazing on medium-to-low quality forages during summer and low quality forages within the succeeding months and had ad libitum access to a mixture of alfalfa hay (40%) and wheat straw (60%) in the afternoons. From 3 weeks before breeding till 1 month after the introduction of rams, 300 g of barley grain/head/day was offered to the ewes and then the supplemental grain was reduced to 100 g/head/day. For better synchronization of estrus cycles in ewes, they were isolated from the rams for at least 2 months and then kept in close proximity of the rams for 1 week before the introduction of the rams to the ewe flock. Then, whole blood samples were collected on days 1, 7, 21, and 120 after ram introduction. Vitamins A, E, and C were measured in plasma. Malondialdehyde (MDA) was measured in the hemolysate as a biomarker of lipid peroxidation. Plasma progesterone (P4) was measured in the samples of day 120 for assessing pregnancy status of the ewes. Vitamins A and C showed continuous and significant declines (P < 0.05) through days 1 to 120. Vitamin E declined only during the first 21 days of the study and remained almost constant till day 120. MDA concentration increased significantly at day 21. An elevated concentration of MDA was also detected at day 120. The difference between days 21 and 120 was not significant (P > 0.05). A positive correlation between vitamins E and C was detected at day 120 (r = 0.349, P < 0.01). Age and BCS did not affect the patterns of changes. Assuming that the ewes with P4 concentrations ≥2.5 ng/ml were pregnant, 95 out of 105 ewes (90.5%) were pregnant at day 120 of the study. Under the conditions of the present study with medium-to-low quality pastures as the main sources of feed, ewes of various ages and body conditions may suffer from oxidative stress during breeding and pregnancy.

Investigation into omocysteine, vitamin E and malondialdehyde as indicators of successful artificial insemination in synchronized buffalo cows (Bubalus bubalis)

“…In P and EM groups we found that MDA increased progressively while VitE decreased, indicating rising oxidative stress and presumably high levels of ROS production until 28 d when both parameters plateaued. Similar VitE and MDA trends have been observed in pregnant sheep by Mohebbi-Fani et al (2012) supporting our hypothesis.…”

Automation of Methods for Determination of Lipid Peroxidation

“…The principle of this method consists in the reaction of MDA with thiobarbituric acid in acidic conditions and at a higher temperature to form a pink MDA-(TBA)2 complex (Fig. 2), which can be quantified spectrophotometrically at 532 nm [17,[66][67][68][69][70]. TBARS method measures the amount of MDA generated during lipid peroxidation, however, other aldehydes generated during lipid peroxidation, which also absorb at 532 nm, may react with TBA [71].…”

Reproduction Is Associated with a Tissue-Dependent Reduction of Oxidative Stress in Eusocial Female Damaraland Mole-Rats (Fukomys damarensis)

“…It has been proposed that elevated reproductive effort should increase an animal's vulnerability to oxidative stress [9], [10], [11], and this has been demonstrated in some bird and reptile species [9], [12], [13], [14], [15], [16]. In eutherian mammals, ROS production is elevated, in part, by mitochondrial activity of the placenta[17], [18], and during gestation sows, humans and sheep exhibit an increase in oxidative damage along with a reduction in antioxidant capacity[19], [20], [21], [22], [23](but see[24]). Oxidative damage also increases with number or mass of offspring produced in sheep, mice and Eastern chipmunks ( Tamias striatus ) [25], [26], [27], [28].…”