Reference intervals for serum reactive oxygen metabolites, biological antioxidant potential, and oxidative stress index in adult rams

Ceruloplasmin Interferes with the Assessment of Blood Lipid Hydroperoxide Content in Small Ruminants

Simple and inexpensive analytical methods for assessing redox balance in biological matrixes are widely used in animal and human diagnostics. Two of them, reactive oxygen metabolites (ROMs) and total oxidant status (TOS), evaluate the lipid hydroperoxide (LOOH) content of the sample and are based on iron-mediated mechanisms. However, these tests provide uncorrelated results. In this study, we compared these two tests in the blood serum of goat kids and lambs, together with an evaluation of ceruloplasmin (CP) oxidase activity. No significant correlation was found between ROMs and TOS, or between TOS and CP oxidase activity, in either species. Conversely, ROMs and CP oxidase activity were highly correlated in both kid and lamb samples (p < 0.001). A significant progressive reduction in the analytical signal in the ROMs assay was observed when sodium azide, an effective CP inhibitor, was added to the samples before the assay (p < 0.001). This decrease was related to sodium azide concentration (p < 0.01) and was not found when sodium azide was added at the same concentrations in the TOS assay. These findings suggest that ROMs, unlike TOS, may be affected by CP, which interferes with LOOH detection in blood samples.

Assessment of total (anti)oxidant status in goat kids

The redox potential of goat serum was assessed by different spectrophotometric assays. Among them, three methods are commonly applied for the evaluation of the oxidative (reactive oxygen metabolites, ROMs, and total oxidant status, TOS) and nitrosative (NO ⚫ metabolites, NO x ) stress, and four methods for the evaluation of the antioxidant status: the total antioxidant capacity (TAC) based on the ferric reducing ability of plasma (FRAP), the total antioxidant activity (TAA) based on the reduction of the coloured ABTS ⚫ + radical cation, the free radical scavenging activity (FRSA) based on the reduction of the purple DPPH ⚫ , and the total thiol levels (TTLs) based on their interaction with DTNB to form a highly coloured anion. Besides, myeloperoxidase (MPO) and ceruloplasmin oxidase (CP) activities were also assessed. Except for TAA, analytical data showed a great inter-individual variation for both oxidant and antioxidant assays. ROMs were strongly correlated with CP, while TOS with MPO and TAC. Furthermore, a tendency between TOS and FRSA was shown. NO x was correlated with TAC and TAA, and a tendency with TOS was shown. No correlations appeared among the antioxidant assays, even if a tendency between TAC and TAA was evidenced, but TAC was correlated with MPO activity. The observed correlation between ROMs and CP is discussed as a possible analytical interference. The absence of correlation among the antioxidant biomarkers suggests the simultaneous use of a panel of tests to verify any changes in the redox balance, mainly in livestock in which reference values for each biomarker are lacking.

Hematologic, biochemical, hormonal, and redox status alterations during reproductive activity in adult rams of two breeds

BACKGROUND

Reproduction is a crucial, energy-consuming physiologic activity, which can temporarily disturb the homeostatic balance of the organism. Although rams are commonly placed in intense breeding programs on contemporary sheep farms, the clinicopathologic and redox status alterations have not been adequately studied during reproductive activity.

OBJECTIVES

The objective was to investigate the clinicopathologic and redox status changes in rams during reproductive activity.

METHODS

Thirty-seven (19 Chios and 18 Florina breed) adult, healthy rams were individually mated with ten estrus-synchronized ewes of the same breed. Blood samples were collected prior to mating, during mating, and postmating. CBC (Advia 120), cytologic blood smear evaluation, biochemical analyses (Flexor E, AVL 9180 Electrolyte Analyzer), and thyroxine measurements (Immulite 1000) were performed. The reactive oxygen metabolites (d-ROMs) test, the biological antioxidant potential (BAP) test, and oxidative stress index were used to assess redox status. The linear mixed effects model (statistical language R) was used for statistical analyses.

RESULTS

Many, mostly breed-independent, clinicopathologic changes were detected during reproductive activity. Conversely, redox status alterations were found to be breed-dependent.

CONCLUSIONS

Intense reproductive activity was related to mild, acute muscle damage in both breeds and mild oxidative stress in Florina rams, whereas Chios rams exhibited oxidative stress resistance. The observed clinicopathologic and redox status alterations were generally consistent with those reported during various forms of physical activity and exercise in animals and humans. Intense reproductive activity does not seem to be physiologically innocuous; however, it appears to be a relatively mild muscle-damaging physical activity.