Differences in blood haptoglobin and length-mass relationships in river otters (Lutra canadensis) from oiled and nonoiled areas of Prince William Sound, Alaska

Acute phase reactants in nondomesticated mammals-A veterinary clinical pathology perspective

Applications for acute phase reactants (APRs) in nondomesticated mammals include identifying inflammatory disease, monitoring the course of specific disease processes and recovery during rehabilitation, detecting preclinical or subclinical disease, being used as bioindicators for monitoring population and ecosystem health, and as markers of stress and animal welfare. Serum amyloid A, haptoglobin, C-reactive protein, fibrinogen, albumin, and iron are most commonly measured. The procedure for evaluating an APR in a nondomesticated mammalian species should follow a stepwise approach beginning with an assessment of analytical performance, followed by an evaluation of overlap performance, clinical performance, and impact on patient outcomes and management. The lack of species-specific standards and antibodies for nondomesticated mammals presents a challenge, and more attention needs to be focused on assessing cross-reactivity and ensuring adequate analytical performance of APR assays. Sample selection for the initial evaluation of APRs should consider preanalytical influences and should originate from animals with confirmed inflammatory disease and healthy animals. Reference intervals should be generated according to published guidelines. Further evaluation should focus on assessing the diagnostic utility of APRs in specific disease scenarios relevant to a species. Greater attention should be paid to assay performance and uniformity of methods when using APRs for population and ecosystem surveillance. Veterinary clinical pathologists should work closely with zoo veterinarians and wildlife researchers to optimize the accuracy and utility of APR measurements in these various conservation medicine scenarios.

Erythrocyte sedimentation rate and hemoglobin-binding protein in free-living box turtles (Terrapene spp.)

The acute phase response is a highly conserved reaction to infection, inflammation, trauma, stress, and neoplasia. Acute phase assays are useful for wildlife health assessment, however, they are infrequently utilized in reptiles. This study evaluated erythrocyte sedimentation rate (ESR) in eastern (Terrapene carolina carolina) and ornate box turtles (Terrapene ornata ornata) and hemoglobin-binding protein (HBP) in T. ornata. Erythrocyte sedimentation rate in 90 T. carolina and 105 T. ornata was negatively associated with packed cell volume and was greater in unhealthy turtles (p < 0.05). Female T. ornata had higher ESR values than males (p < 0.05). Measurement of ESR with a microhematocrit tube proportionally overestimated values from a commercial kit (Winpette), though both methods may retain utility with separate reference intervals. Hemoglobin-binding protein concentration in 184 T. ornata was significantly increased in adults and unhealthy turtles (p < 0.05). Erythrocyte sedimentation rate values were similar between seasons and populations, and HBP values were consistent between years, indicating that these analytes may have more stable baseline values than traditional health metrics in reptiles. This study demonstrates that ESR and HBP are promising diagnostics for health assessment in wild box turtles. Incorporating these tests into wild herptile health assessment protocols may support conservation efforts and improve ecosystem health monitoring.

Serum haptoglobin response in red deer naturally infected with tuberculosis

The analysis of haptoglobin (Hp) serum concentration is a very sensitive, but non-specific, indicator of inflammation or infection. Methods to accurately diagnose infection in vivo in wildlife are usually constrained by low sensitivity due to the effects of stress on individual immune response and the challenging logistics of performing tests in the wild. Firstly, we sought to determine serum Hp concentration in red deer (Cervus elaphus) naturally infected with bovine tuberculosis (TB). Secondly, we assessed the complementary diagnostic value of serum Hp levels in conjunction with the cervical comparative skin test (CCT) performed in a subsample (n = 33). Serum Hp concentrations were significantly higher in TB-infected individuals (based on the presence of macroscopic lesions confirmed by culture) compared to those uninfected. In addition, serum Hp significantly changed with the type of animal handling, with captured and handled animals showing higher levels of Hp than hunted animals. Four out of 6 TB positive individuals that tested negative to the CCT (false negatives) showed Hp levels higher than the 95th percentile of healthy animals. These findings indicate that an acute phase response develops in animals with TB. In this paper, we demonstrate for the first time that an acute phase protein can provide a complementary assessment for specific diagnosis tests in wild species.

Acute phase protein haptoglobin in blood plasma samples of harbour seals (Phoca vitulina) of the Wadden Sea and of the isle Helgoland

Haptoglobin (Hp) which is synthesized in response to infection, inflammation, trauma or toxicological damage is known as a major acute phase protein in numerous species. Quantification of the circulating concentration of this protein can provide an objective measure of the health status, but there is a lack of investigations on harbour seals. We investigated the Hp concentration in samples of 123 seals (Phoca vitulina) from the German and Danish Wadden Sea to study physiological ranges of Hp levels. Hp levels between 2002, the end of the phocine distemper virus epidemic (PDV), and 2007 were considered, and Hp concentrations between animals of different sex, ages as well as living areas were compared. Furthermore, as a case study, six animals from the open sea isle Helgoland were investigated in 2006. Influences on the health status of the seal population e.g. the PDV epidemic were reflected by increased Hp levels in North Sea seals in 2002. The results of the Wadden Sea seals showed no significant age-, sex-, or geographical area-related differences. Interestingly, for the seals of the open sea isle Helgoland higher Hp values were measured compared to the Wadden Sea seals. The present study demonstrates that Hp can be used as a diagnostic tool to monitor the health status of harbour seals.

Correlates to survival of juvenile sea otters in Prince William Sound, Alaska, 1992–1993

We estimated survival of sea otters (Enhydra lutris) for 1 year post weaning during 1992–1993 in Prince William Sound (PWS), location of the 1989 Exxon Valdez oil spill. We sampled 38 pups in eastern PWS (EPWS), an unoiled area occupied by sea otters for <15 years, and 33 pups from oiled western PWS (WPWS), occupied for >25 years. We compared survival between areas, sexes, and condition groups. We also examined the relation of blood parameters to survival. Survival was estimated at 0.74 in EPWS and 0.52 in WPWS. Female survival was 0.86 in EPWS and 0.64 in WPWS, whereas male survival was lower, 0.61 in EPWS and 0.44 in WPWS. Sea otters from EPWS were in better condition (mass/length) than WPWS sea otters. Pups in better condition had higher survival in EPWS but not in WPWS. Foraging success was greater in EPWS than in WPWS, consistent with either an effect of length of occupation or the effects of oil on the prey base or a combination of these effects. Area differences in blood parameters suggested liver damage in WPWS sea otters, perhaps resulting from continued exposure to oil. Thus, both length of occupation and oiling history likely influenced juvenile survival in PWS.

Response of river otters to experimental exposure of weathered crude oil: fecal porphyrin profiles

Profiles of porphyrins were characterized in fecal samples from river otters (Lontra canadensis) experimentally exposed to weathered crude oil to determine effects on heme synthesis. Fifteen male river otters were randomly assigned to three groups of five individuals each representing a control group, a low-dosage group that received 5 mg/kg body mass of oil per day, and a high-dosage group that received 50 mg/kg body mass of oil per day. Mean levels of coproporphyrin III (CoproIII) and protoporphyrin IX (ProtoIX) in fecal samples collected from all experimental river otters were higher throughout the experimental period than levels of CoproIII and ProtoIX in fecal samples collected previously at two field sites. No statistically significant differences in levels of CoproIII and ProtoIX were observed between treatment groups, although a trend of reduction in variability in CoproIII was observed in the low- and high-dose groups. We found no relation between levels of CoproIII and ProtoIX, suggesting that the process of disruption that leads to oxidation of the precursors of porphyrins is probably nonlinear. Our results also indicate that the interaction between oiled induced reduction in hemoglobin levels and induction of CYP1A1 corresponded with significantly lower levels of ProtoIX in the fecal samples, possibly representing high demand for ProtoIX. Therefore, while this experiment does not support the use of porphyrin profiles as an individual biomarker, it does suggest that the latter may be valuable when a weight of evidence is used in an ecotoxicological risk assessment in which the interactions between several biomarkers are explored.

Immunotoxicity risks associated with land-treatment of petrochemical wastes revealed using an in situ rodent model

Land-treatment of petrochemical wastes is a widely used method to dispose of hazardous and non-hazardous waste by biodegradation. However, no comprehensive assessment of the impact of such disposal techniques on terrestrial ecosystems has been conducted. Despite the presence of suspected immunotoxicants in the soil, wild rodents frequently reside on these waste sites after closure or abandonment. We explored the seasonal sensitivity of the immune system of the hispid cotton rat (Sigmodon hispidus) to in situ exposures on sites land-treated with petrochemical wastes. Animals were monitored on five contaminated land-treatment sites and five ecologically matched-reference sites in Oklahoma, USA, over two seasons (summer and winter). Most hematological parameters were not adversely affected by land-treatment; however, platelet counts were 26% greater in cotton rats from land-treatment sites compared to reference sites in winter. Significant treatment-related differences were observed in total serum protein concentrations, organ mass and organ cellularity, but these differences were not consistent across the five land-treatment units. Lymphoproliferative responses of cotton rat splenocytes stimulated in vitro were elevated for a T-cell mitogen and depressed for a B-cell mitogen in animals from land-treatment compared to reference sites. The ability of splenocytes to proliferate in response to interleukin-2 receptor-binding was not influenced by treatment. Total yields of peritoneal cells, yield of peritoneal macrophages, and yield of peritoneal lymphocytes were influenced to varying degrees by land-treatment. Functionally, in vitro metabolic activity of peritoneal macrophages was 114% greater in cotton rats from land-treatment sites compared to reference sites during summer. These results indicate that petrochemical wastes applied to soils on these five land-treatment sites had variable immunomodulatory effects in resident cotton rats. Immune alterations for some assays were indicative of enhancement on some land-treatment sites while suppressive on other land-treatment sites, which could have been a function of type and concentration of immunotoxicants present on each site and highlights the uniqueness of each land-treatment site.

Effects of oiling on exercise physiology and diving behavior of river otters: a captive study

Following the Exxon Valdez oil spill (EVOS), river otters (Lontra canadensis) on oiled shores had lower body mass, selected different habitat characters, and had larger home ranges and less diverse diets than did otters living in non-oiled areas. We explored the possibility that these changes were due to the effect of crude oil contamination on physiological and behavioral processes in otters. Fifteen otters were exposed to two levels of oil contamination under captive controlled conditions at the Alaska Sealife Center in Seward, Alaska, U.S.A. We collected blood samples for hematological examinations and measured oxygen consumption in otters exercising on a motorized treadmill. We also observed diving and foraging behavior of otters offered live fish. Otters exposed to oil became anemic relative to controls. While oxygen consumption of resting river otters was not related to changes in hemoglobin concentration, exercising river otters with decreased hemoglobin levels displayed significantly increased oxygen consumption (P = 0.042). Oiled otters also performed fewer dives when chasing fish (P = 0.04), representing a potential decrease of 64% in the capture rate of prey. Our data strongly support the hypothesis that changes in prey types and home-range utilization by oiled river otters following EVOS were influenced by hematological changes, associated increases in energetic costs, and reduced diving ability.

Geographic variation in blood plasma protein concentrations of young herring gulls (Larus argentatus) and Caspian terns (Sterna caspia) from the Great Lakes and Lake Winnipeg

Relative and total amounts of plasma protein fractions are affected by infections, inflammation, and nutritional and physiological status, and are therefore important health indicators in free-living animals. Our objectives were: (1) to examine intercolony differences in plasma protein fractions in prefledgling gulls and terns; (2) to investigate relationships between plasma proteins and other physiological measures such as weight loss, growth, and immune function; and (3) to examine potential associations between organochlorine exposure and plasma proteins. During 1992, blood was collected from 3-week-old herring gull (Larus argentatus) chicks from six sites on Lakes Superior, Huron, Michigan, Erie, and Winnipeg and from 3-week-old Caspian tern (Sterna caspia) chicks from five sites on Lakes Huron, Michigan, and Ontario. These sites provided a wide gradient of organochlorine contamination. Plasma proteins were separated by high-resolution agarose gel electrophoresis and stained with Coomassie brilliant blue dye. Six major fractions were quantified: prealbumin, albumin, alpha-globulins, beta(1)-globulins, beta(2)-globulins, and gamma-globulins. Total protein, prealbumin, albumin, and gamma-globulin concentrations and the albumin/globulin ratio did not differ among sites. Total protein, albumin, and the albumin/globulin ratio were not decreased in birds experiencing food stress or weight loss. Intersite differences were found in alpha- and beta-globulins. In gulls, beta(2)-globulins were positively associated with polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ether (DDE). In terns, PCBs were negatively associated with alpha-globulins and positively associated with beta(1)-globulins. Additional research is needed to identify individual proteins and elucidate causal relationships between the particular protein concentrations and factors such as contaminants, growth, and condition.

Timing of reproduction in wild mink: the influence of spawning Pacific salmon

In many species of seasonally breeding mammals, reproduction occurs later at higher latitudes. Records of timing of reproduction in free-ranging American mink (Mustela vison) in North America and Europe suggest a similar trend. Observations on mink in southeast Alaska, however, revealed a deviation from this pattern, suggesting that factors other than latitude and associated day length may affect timing of breeding for this species in this area. I investigated timing of reproduction and body condition of wild, free-ranging mink on Chichagof Island, southeast Alaska, and hypothesized that seasonal food availability, especially abundant carcasses of spawning Pacific salmon (Onchorhynchus sp.), would determine timing of breeding in this population of mink. Blood progesterone levels, body condition, and testicle lengths were recorded for 24 adult mink, livetrapped from mid-March to late July in 1992 and 1993. Results suggest that these free-ranging mink mate during the later part of April to early May, and parturition occurs in late June to early July. Although male mink seemed to respond to photoperiodism in initiating reproduction, timing of reproduction in female mink was shifted so that lactation coincided with the availability of carcasses of Pacific salmon.