Effects of plane of nutrition on oxidative stress in goats during the peripartum period

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Abstract

This study aimed to monitor the effect of a high (HD; 140% of energy requirements) versus a low diet (LD; 80% energy requirements) on oxidative status in goats during the peripartum period. Blood samples were taken from all goats at −2, −1, 0 (partum), +2 and +4 weeks from delivery. Blood samples were assayed for their content of reactive oxygen metabolites (ROMs), thiol (SH) groups, total antioxidant capacity (OXY) and for glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities. The observation that ROMs levels significantly increased during the peripartum period was accompanied by a decrease of GSH-Px activity at weeks 2 and 4 postpartum, which suggested that the goats might have experienced some degree of oxidative stress and lipid peroxidation. Overall, changes to the nutritional level of the diet had very little or no effect on redox homeostasis. The lack of any correlation between the biomarkers measured indicated that each oxidative stress marker responded differently, indicating that redox homeostasis was impaired in these dairy goats during the peripartum period.

Introduction

Recent developments in the evaluation of oxidative stress in farm animals have contributed significantly to our understanding of the fundamental processes involved in metabolic disorders (Lykkesfeldt and Svendsen, 2007). Oxidative stress is believed to play an important role in regulating the metabolic activity of some organs and productivity in farm animals. Oxidative stress results when pro-oxidants (free radicals) exceed the capacity of antioxidants. A free radical is defined as any species capable of independent existence that contains one or more unpaired electrons (Halliwell and Gutteridge, 1989). Reactive oxygen metabolites (ROMs) are capable of attacking all of the major classes of biomolecules, although lipids are particularly susceptible (Miller et al., 1993).

Oxidative stress can be particularly dangerous because no clinical symptoms are shown and the condition is diagnosed by means of dedicated analytical methods. ROMs have several normal physiological functions (Droge, 2002), but ‘oxidative stress’ will occur when excess production cannot be counteracted by antioxidant mechanisms, potentially leading to pathological changes (Lykkesfeldt and Svendsen, 2007). Several defence mechanisms are available to prevent oxidative damage (for a review see Lykkesfeldt and Svendsen, 2007), including scavenging systems, such as the enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). In addition, thiol (SH) groups, commonly found in the cysteine side chain, are the most chemically reactive sites on proteins, such as albumin, and have strong reducing properties (Soriani et al., 1994, Moran et al., 2001).

In dairy cows, pregnancy and lactation are physiological stages considered to induce metabolic stress (Drackley, 1999). For example, dairy cows can experience oxidative stress (Bernabucci et al., 2005, Castillo et al., 2006), which may be associated with metabolic diseases during the peripartum period (Miller et al., 1993). A number of recent studies have reported variable levels of oxidative stress during the peri-parturient period in dairy cows (Bernabucci et al., 2005, Castillo et al., 2005, Gaál et al., 2006). It is important to note that the activity of oxidative stress biomarkers can be influenced by nutrition and season (Bernabucci et al., 2002, Di Trana et al., 2006). For example, feeding high levels of starch in the diet to cows at 80 days lactation increased oxidative stress, possibly due to cellular changes related to oxidative phosphorylation (Gabai et al., 2004). The adoption of intensive methods of husbandry in goats for higher milk yields (Rubino et al., 1995) is likely to increase the incidence of metabolic diseases.

The relationship between diet composition and oxidative stress has received little research interest in goats during late pregnancy and the beginning of lactation although, based on studies in dairy cows (Bernabucci et al., 2005, Sordillo et al., 2007), the oxidative status of dairy goats may be impaired during the transition period. The object of the present experiment was to evaluate the effect of diets of different nutritional level on the oxidative status of goats during the peripartum period.

Section snippets

Animals, location and experimental protocol

The study was conducted in Southern Italy (40°38′N; 15°49′E) during the month of October at the Unità di Ricerca per la Zootecnia Estensiva (CRA) experimental farm located at 360 m above sea level. We used 14 Red Syrian goats balanced for age (4–5 years), bodyweight (BW; 48 ± 1.6 kg) and body condition score (BCS; 2.0 ± 0.1). In May, the goats were oestrous synchronised and mated so that kidding occurred within the first week of October.

All animals were housed in an experimental building where they

Results

During the experimental period goats LW and BCS were not affected by the dietary treatments adopted and, as expected, LW significantly decreased after parturition (for a detailed description of productive performances see Celi et al., 2008a). Plasma concentrations of ROMs increased significantly during the trial (P < 0.001), reaching their highest levels 2 weeks after parturition, but concentrations did not differ between the HD and LD groups (Fig. 1). Similarly, the activity of blood GSH-Px and

Discussion

This study indicated that goats were exposed to an increased risk of oxidative stress during the peripartum period, as suggested by the observed decreases in GSH-Px and SOD activities and by the increase in ROM concentration. Overall, that energy content of the diet did not seem to have an effect on the oxidative status biomarkers measured.

The observation that ROM levels significantly increased during the peripartum period is in agreement with previous observations made in dairy cows (

Conclusions

Our results showed that changing the profiles of oxidative status markers in goat plasma revealed an increase in the risk of oxidative stress during the peripartum period. However, the lack of any correlation between the biomarkers measured suggested that each oxidative stress marker responded differently, and that redox homeostasis was impaired in dairy goats during the peripartum period.

Conflict of interest statement

None of the authors of this paper has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper.

Acknowledgement

This research was supported by the Italian Ministry of Education, University and Scientific Research, project PRIN 2003.

References (43)

  • T. Gaál et al.

    Free radicals, lipid peroxidation and the antioxidant system in the blood of cows and newborn calves around calving

    Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology

    (2006)
  • B. Halliwell et al.

    Lipid peroxidation: its mechanism, measurement, and significance

    American Journal of Clinical Nutrition

    (1993)
  • J.P. Kehrer et al.

    Free radicals in biology: sources, reactivities, and roles in the etiology of human diseases

  • J. Lykkesfeldt et al.

    Oxidants and antioxidants in disease: oxidative stress in farm animals

    The Veterinary Journal

    (2007)
  • J.K. Miller et al.

    Oxidative stress, antioxidants, and animal function

    Journal of Dairy Science

    (1993)
  • R. Rubino et al.

    Milk production of goats grazing native pasture under different supplementation regimes in southern Italy

    Small Ruminant Research

    (1995)
  • S. Sgorlon et al.

    Variation of starch and fat in the diet affects metabolic status and oxidative stress in ewes

    Small Ruminant Research

    (2008)
  • L.M. Sordillo et al.

    Shifts in thioredoxin reductase activity and oxidant status in mononuclear cells obtained from transition dairy cattle

    Journal of Dairy Science

    (2007)
  • M. Soriani et al.

    Antioxidant potential of anaerobic human plasma: role of serum albumin and thiols as scavengers of carbon radicals

    Archives of Biochemistry and Biophysics

    (1994)
  • A. Tüzün et al.

    Oxidative stress and antioxidant capacity in patients with inflammatory bowel disease

    Clinical Biochemistry

    (2002)
  • P.M. Ueland et al.

    Reduced, oxidized and protein-bound forms of homocysteine and other aminothiols in plasma comprise the redox thiol status-A possible element of the extracellular antioxidant defense system

    Journal of Nutrition

    (1996)
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