Environmental exposure to polychlorinated biphenyls among raccoons (Procyon lotor) at the paducah gaseous diffusion plant, Western Kentucky, USA.

An investigation involving raccoons (Procyon lotor) as a sentinel species at the Paducah Gaseous Diffusion Plant (PGDP) in Western Kentucky (USA) delineated the extent of exposure to polychlorinated biphenyls (PCBs) and PCB spatial distribution. Raccoon exposure to PCBs was demonstrated through analysis of subcutaneous fat, abdominal fat, liver, and brain tissues from raccoons collected at the PGDP but also was clearly evident in raccoons from a reference area situated along the Ohio River (USA). Raccoons with the highest tissue PCB concentrations appeared to be those inhabiting areas nearest the plant itself and most likely those that ventured into the plants interior. Male raccoons at the PGDP had similar concentrations of total PCBs in subcutaneous fat (1.86 +/- 0.64 microg/g) as males from the reference site (1.41 +/- 0.35 microg/g), but females had higher PCB body burdens than those at the reference site (9.90 +/- 6.13 microg/g vs 0.75 +/- 0.40 microg/g). Gross measurements of exposure to radiation-producing materials revealed that counts per minute exceeded background in 61% of PGDP raccoons compared with 27% at the reference site and five raccoons at the PGDP had beta counts that were more than twice the background. Differences among trapping success, growth rates, and serum chemistry parameters were noted but may have been related to habitat and other environmental and population density factors.

Effect of dietary glycine and benzoate level on benzoate metabolism in mink (Mustela vision), blue fox (Alopex lagopus), and raccoon dog (Nyctereutes procyonoides).

Three 2 x 4 factorial experiments were carried out from August to September with 30 juvenile male mink, 24 raccoon dogs, and 24 blue foxes to investigate the effect of dietary glycine supply (low or high) on the efficiency of these species to excrete hippuric acid with incremental benzoate intake (0, 1, 2, or 4 mmol/kg BW). For mink, two additional treatments with 1 or 2 mmol/kg BW of ethyl benzoate were included. A basal low-glycine diet was formulated to meet the minimum protein requirements of fur animals (30% of ME). This diet was supplemented with 0 or 3 g/kg of glycine, or with 0, 1.0, 2.07, or 4.15 g/kg of sodium benzoate for mink and blue foxes, and with 0 or 4.5 g/kg of glycine and 0, 1.58, 3.17, or 6.34 g/kg of sodium benzoate for raccoon dogs, respectively. Two additional diets with .76 or 1.53 g/kg of ethyl benzoate were made for mink. Fecal and urinary benzoic and hippuric acid excretion were measured for 3 d. The 24-h recovery of [14C]benzoic acid injected intraperitoneally was measured from urine, the liver, and the kidneys. All animals appeared healthy and no clinical signs of benzoate overdose were observed. Dietary benzoate level did not affect ADFI or ADG in any species. Glycine supplementation lowered ADFI in mink. The majority of ingested benzoates were absorbed from the gut (over 95%), except in blue foxes, which excreted 6 to 15% of ingested benzoates in feces with incremental increases in benzoate intake. Urinary free benzoic acid excretion accounted for 10% of the ingested benzoates in blue foxes but less than 5% in mink and raccoon dogs. When benzoate intake was 1 mmol/kg BW, mink, blue foxes, and raccoon dogs excreted 71, 77, and 34% of ingested benzoates as hippuric acid in urine, respectively. With higher benzoate intakes, urinary hippuric acid excretion decreased quadratically with mink to 20%, and linearly with blue foxes and raccoon dogs to 45 and 16%, respectively. The hippuric acid pathway appears to be the principal route of benzoate elimination in the mink and blue fox, whereas, in the raccoon dog, other pathways appear to be more important. In mink, the elimination of ethyl benzoate did not differ from that of sodium benzoate. Because glycine conjugation is the primary route of benzoate elimination, it is recommended that benzoate content in fur animal feeds should not exceed 1 g/kg feed on an as-fed basis.

Immunoreactivity for GAD and three peptides in somatosensory cortex and thalamus of the raccoon.

Immunocytochemical methods were used to determine the distributions of glutamic acid decarboxylase (GAD), vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), and somatostatin (SOM) in the primary somatosensory cortex and somatosensory thalamus of adult raccoons. The cortex showed extensive immunoreactivity for GAD, revealing a large population of GABAergic neurons. GAD-labeled cells were numerous in all cortical layers, but were most concentrated in laminae II-IV. The cells were nonpyramidal and of varying morphology, typically with somata of small or medium size. GAD-immunoreactive puncta, presumably synaptic terminals, were widespread and often appeared to end on both GAD-negative and GAD-positive neurons. Immunoreactivity for the peptides was much less extensive than that for GAD, with the number of labeled neurons for VIP > CCK > SOM. Peptidergic cells were preferentially located in the upper and middle cortical layers, especially laminae II and III. The cells were nonpyramidal, often bitufted or bipolar in morphology, and small to medium in size. Their processes formed diffuse plexuses of fibers with terminal-like varicosities that occasionally surrounded nonpeptidergic neurons. The thalamus showed a clearly differentiated pattern of immunoreactivity for GAD, but little or no labeling for the three peptides. Nuclei adjoining the ventral posterior lateral (VPL)/ventral posterior medial (VPM) complex--including the reticular nucleus--contained many GAD-positive neurons and fibers. In contrast, the VPL and VPM nuclei displayed considerably less GAD immunoreactivity, somewhat surprising given the raccoon's highly developed somatosensory system. However, the ventral posterior inferior (VPI) nucleus revealed rather dense GAD labeling, perhaps related to a specialized role in sensory information processing. Thus, the primary somatosensory cortex of the raccoon showed patterns of immunoreactivity for GAD and peptides that were similar to those of other species; the somatosensory thalamus revealed a distinctive profile of GAD immunoreactivity, with labeling that was light to moderate in the VPL/VPM complex and relatively extensive in VPL.

Selenium accumulation by raccoons exposed to irrigation drainwater at Kesterson National Wildlife Refuge, California, 1986.

In February-March 1986, eight raccoons (Procyon lotor) were collected at Kesterson Reservoir (Merced Co., California), which had received selenium-contaminated irrigation drainwater, and four raccoons were collected at the nearby Volta Wildlife Area, which had not. Selenium concentrations in Kesterson raccoons averaged 19.9 ppm (micrograms/g dry wt) in liver, 28.3 ppm (dry wt) in hair, 21.6 ppm (dry wt) in feces, and 2.61 ppm (wet wt) in blood and exceeded Volta concentrations by 12, 30, 21, and 10 times, respectively. Selenium concentrations in livers of Kesterson raccoons were less than those in five of nine other mammal species sampled in 1984. Selenium concentrations in hair provided the strongest statistical separation between study areas. Hemoglobin levels in two Kesterson raccoons equalled levels reported in rats with selenium-induced anemia, but the raccoons showed no illness. Amyloidosis in one Kesterson raccoon may have been selenium-induced. Our data indicate that raccoon births peaked about 2 months later than was previously reported. Based on our sample of 12 raccoons, we found no evidence that contamination by irrigation drainwater had negative effects on raccoons inhabiting Kesterson.