A Quantitative Analysis of Microplastics in the Gastrointestinal Tracts of Odontocetes in the Southeast Region of the United States.

Microplastics (<5 mm in diameter) are ubiquitous in the oceanic environment, yet microplastic accumulation in marine mammals is vastly understudied. In recent years, efforts have been made to document microplastic profiles in odontocetes. The objective of the present study was to describe and quantify microplastics in the gastrointestinal (GI) tracts of deceased odontocetes that stranded in the southeastern United States. Our study included 24 bottlenose dolphins (Tursiops truncatus), two pygmy sperm whales (Kogia breviceps), one pantropical spotted dolphin (Stenella attenuata), one short-snouted spinner dolphin (Stenella clymene), one Risso's dolphin (Grampus griseus), and one dwarf sperm whale (Kogia sima) obtained from stranding networks in Texas, Alabama, Florida, and Puerto Rico. Contents found in the GI tracts, namely, the stomach and portions of the intestinal tract, were subjected to a laboratory procedure to isolate microplastics. The physical characteristics of microparticles were analyzed with a stereomicroscope, and microplastics were classified by polymer type via Fourier-transform infrared spectroscopy. There was an average of 47.6 ± 41.4 microparticles, ranging from 1 to 193 items per stomach. More specifically, there was an average of 5.6 ± 4.7 microplastics per stomach. The predominant morphologies, colors, and polymer types were fibers, white-colored items, and polyester, respectively. This research contributes to the current knowledge of microplastic exposure in top marine mammal predators and sets the stage for further exploration into the associated risks of microplastics in odontocetes within the United States and worldwide. Environ Toxicol Chem 2024;43:1260-1273. © 2024 SETAC.

Evaluation of Serum for Pathophysiological Effects of Prolonged Low Salinity Water Exposure in Displaced Bottlenose Dolphins (Tursiops truncatus).

We conducted a retrospective study of serum biochemistry and hematologic findings from displaced, out-of-habitat bottlenose dolphins (Tursiops truncatus) exposed to various low salinity environments in waters along the southern United States including southeastern Atlantic and northern Gulf of Mexico. Serum sodium, chloride, and calculated osmolality were significantly lower and below reference ranges in displaced animals compared to free-ranging case control animals. This suggests clinical hyponatremia, hypochloremia, and hypo-osmolality due to an uptake of low saline water from the environment. In addition, significant differences were found in other serum chemistry variables, although none were outside of normal reference ranges for non-controlled free-ranging animals. Multiple linear regressions demonstrated the degree of salinity had a greater pathophysiologic response than the duration of fresh water exposure. The Na/Cl ratio and bicarbonate were the only variables that were significantly modulated by exposure duration. These findings suggest that the degree of salinity is a critical factor when assessing and managing care for dolphins chronically exposed to low salinity water. Results from this study indicate that changes in various biochemical parameters can be used to determine fresh water exposure and aid in determining the treatment for animals recovered from low salinity waters.

Surgical castration of subadult giraffe (Giraffa camelopardalis).

Surgical castration of giraffe (Giraffa camelopardalis) has not been commonly performed. Large domestic animal castration has a significant complication rate that includes postoperative mortality. Documentation of castration techniques and complications in large domestic animals occurs regularly. However, literature describing castration experiences with large zoo mammals is sparse. In addition, a suitable anesthetic regimen for surgical castration of giraffe has not been confirmed. Open castration using an emasculator plus ligation was performed in three subadult giraffe weighing 555-711 kg. Scrotal incisions were left open and healed in about 6 wk. One animal developed scrotal dermatitis. No other complications occurred. As slow scrotal healing can increase the risk of ascending infection, partial or complete scrotal closure for giraffe may warrant consideration. Experiences with these animals also suggest that closed or modified closed castration may be considered for giraffe of this size. Thiafentanil, medetomidine, and ketamine plus local lidocaine provided suitable anesthesia for surgical castration.

Adaptations of subpalpebral lavage systems used for llamas (Lama glama) and a harbor seal (Phoca vitulina).

Subpalpebral lavage systems (SPLSs) were adapted for use in zoo llamas (Lama glama) and a wild harbor seal (Phoca vitulina) during therapy for severe ulcerative keratitis or corneal perforation. One llama presented with a melting corneal ulcer caused by Pseudomonas aeruginosa, which necessitated frequent application of a topical ophthalmic antibiotic. The lavage system was used routinely during the day and was connected to a balloon infusion system at night to allow for continuous medication administration. The ulcer healed soon after therapy was extended to include overnight treatment with the infusion system. A SPLS system was also combined with a balloon infusor during postoperative treatment of a second llama that had sustained a corneal perforation. Both llamas tolerated the infusor/lavage systems well and regained vision. One llama had minor conjunctival irritation from the SPLS that resolved quickly without treatment. Bilateral SPLS were placed in a wild harbor seal for treatment of severe ulcerative keratitis associated with Candida albicans infection. The seal tolerated the lavage systems well throughout 14 wk of their use in an aquatic environment with other seals. Partial detachment of the lavage systems from the skin of the seal occurred a few times during treatment and was easily corrected. Severe keratitis resolved with administration of antimicrobials through the lavage systems, and the seal was returned to the wild. The use of SPLSs alone or in ombination with balloon infusion systems warrants consideration for exotic, wild, and aquatic animals that cannot tolerate repetitive manual applications of topical ophthalmic medication.