Safety of docosahexaenoic acid (DHA) administered as DHA ethyl ester in a 9-month toxicity study in dogs

The anti-tussive, anti-inflammatory effects and sub-chronic toxicological evaluation of perilla seed oil

BACKGROUND

Perilla seed oil (PSO) is the main constituent of perilla seeds currently being used in the food industry, however it also has great clinical potential in the regulation of lung function as a nutrition supplement because of the high content of α-linolenic acid (ALA). In this study, the pharmacological activities including anti-tussive, expectorant and anti-inflammatory effect of PSO were performed. Furthermore, the 90-day sub-chronic oral toxicity with a 30 day recovery period was evaluated in Wistar rats.

RESULTS

The pharmacological studies demonstrated that PSO inhibited cough frequency induced by capsaicine in mice. PSO also inhibited the leukotriene B4 (LTB4) release from the calcium ionophore A23187-induced polymorphonuclear neutrophils (PMNs) to some extent. In this sub-chronic toxicity study, mortality, clinical signs, body weight, food consumption, hematology, serum biochemistry, urinalysis, organ weight, necropsy, and histopathology were used to evaluate the toxicity of PSO. Lower body weight and various negative impacts on liver related parameters without histopathological lesion were observed in the 16 g kg^-1 groups. No clinically significant changes were discovered in the 4 g kg^-1 group during the test period.

CONCLUSION

In summary, PSO exhibited anti-tussive and anti-inflammatory activities in vivo and in vitro. These sub-chronic toxicity studies inferred that the 'no-observed adverse effect level' (NOAEL) of PSO in Wistar rats was determined to be 4 g kg^-1 . These results may provide a safety profile and a valuable reference for the use of PSO. © 2020 Society of Chemical Industry.

Safety of a novel feed ingredient, Algal Oil containing EPA and DHA, in a gestation-lactation-growth feeding study in Beagle dogs

An Algal Oil Containing EPA and DHA (AOCED) at ~50% was developed as a sustainable source of omega-3 fatty acids. AOCED was incorporated into extruded dry foods for dogs at 0, 0.75%, 1.5% and 3.0% levels (equivalent to 0, 7.5, 15 and 30 g/kg diet) on dry matter basis at the expense of chicken fat and fed to healthy female Beagle dogs starting at mating and throughout gestation and lactation. The offspring were fed their maternal corresponding diets for 26 weeks after weaning. AOCED-enriched diets were well tolerated by dogs in both generations and did not affect their overall health, physiological parameters, food consumption, body weights and body weight gains. There were no changes in hematology, clinical chemistry, and coagulation parameters in both generations of dogs fed the AOCED diets when compared to those in the control group. Plasma levels of DHA and EPA increased significantly and generally dose-dependently in both generations. The study demonstrated the safety of AOCED in dogs during gestation, lactation, and growth periods at dietary levels up to 3.0wt%, equivalent to 30 g/kg diet. AOCED's bioavailability as a source of DHA and EPA in dogs was demonstrated by the increased plasma concentrations of these nutritional lipids.

Acute and sub-chronic 90-day oral toxicity study of Perilla seed oil in rodents and Beagle dogs

Perilla seeds are used as food and traditional medicine in China. This study aimed to investigate the toxicity profile of Perilla seed oil (PSO), which is the main constituent of Perilla seeds in rodents and Beagle dogs. No significant treatment-associated toxicity or mortality was observed at PSO dosages of up to 50 g/kg and 20 g/kg in KM mice and Wistar rats, respectively, suggesting that PSO was well tolerated by the experimental rodents. Sub-chronic oral toxicity of PSO was studied in dogs at doses of 3, 6 and 12 g/kg/d for 90 days followed by a 30 day recovery period. The results indicated that the body weight increased in all-dose groups more than control group, typical of animals on diets rich in fatty acids. Treatment-related side effects, including changes in hematology and serum biochemistry parameters, histopathology of liver and lymph glands, were observed in the high and moderate-dose dogs. However, these changes disappeared after the doses were withdrawn during the recovery period, except for alteration of liver in the high-dose group. In conclusion, the "no observed adverse effect level" (NOAEL) of oral administration of PSO for 90 days in Beagle dogs was considered to be 3 g/kg/d.

Effects of grape seed extract, lutein, and fish oil on responses of canine lens epithelial cells in vitro

OBJECTIVE To determine the effects of grape seed extract (GSE), lutein, and fish oil containing omega-3 fatty acids on oxidative stress, migration, proliferation, and viability of lens epithelial cells (LECs). SAMPLE Lens capsules or cultured LECs obtained from canine cadavers. PROCEDURES An antioxidant reductive capacity assay was used to determine reducing capability of each substance. The LECs were cultured and incubated with various substances, including N-acetyl cysteine (NAC), when appropriate, and dimethyl sulfoxide (DMSO) as positive and vehicle control substances, respectively. A dichlorofluorescein assay was used to evaluate reactive oxygen species (ROS) production, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine cell viability. Ex vivo posterior capsule opacification (PCO) was used to evaluate LEC migration and proliferation. RESULTS Antioxidant reductive effects of GSE surpassed those of NAC, lutein, and fish oil containing omega-3 fatty acids. The GSE reduced ROS production in LECs, compared with the DMSO vehicle control, whereas lutein was pro-oxidative. All test substances reduced cell viability. Ex vivo PCO was not altered by GSE, was decreased by lutein, and was increased by fish oil containing omega-3 fatty acids, compared with results for the DMSO vehicle control. CONCLUSIONS AND CLINICAL RELEVANCE Only GSE had significant antioxidant capabilities and reduced ROS production; however, no effect on ex vivo PCO was detected. Fish oil containing omega-3 fatty acids increased ex vivo PCO. No conclusions could be made regarding antioxidant effects of these substances on LECs. These findings suggested that the substances will not decrease PCO.

Maternal omega-3 polyunsaturated fatty acid supplementation on offspring hip joint conformation

Unsaturated omega-3 fatty acids, especially docosahexaenoic acid (DHA), when fed to dogs improves cognitive and neurological development. Supplementation with omega-3 fatty acids such as DHA and eicosapentaenoic acid (EPA) has also been associated with lipid peroxidation, which in turn has been implicated in reduced body weight and altered bone formation. To assess the impact of omega-3 fatty acid supplementation on skeletal growth, diets containing three levels of DHA and EPA (0.01 and 0.01%, 0.14 and 0.12%, and 0.21 and 0.18%, respectively) were fed to bitches during gestation and lactation with puppies also supplemented through weaning. Thus, the subjects studied were the puppies supplemented with DHA and EPA through gestation and early postnatal life. The hip joint conformation of the puppies (n = 676) was recorded at adulthood using two radiographic, non-invasive evaluations. In this population, females had higher hip distraction indices (DI) than males. Males from the lower two levels of DHA and EPA supplementation had significantly smaller hip DI than all females and males from the highest DHA and EPA supplementation. In contrast, there were no diet effects on anatomical indicators of hip joint conformation and no visible arthritic changes. These data suggest that dietary supplementation of DHA and EPA during gestation and the perinatal period to weaning does not adversely influence hip joint formation of dogs.

Kinetics of docosahexaenoic acid ethyl ester accumulation in dog plasma and brain

This study explores dog plasma and brain fatty acid composition achieved after long-term supplementation at high DHA doses. A 90% concentrate of DHA Ethyl Ester (DHA-EE) administered by oral gavage to Beagle dogs at doses of 100, 500, 1000, and 2000mg/kg bw/day for 8 weeks resulted in DHA increases in both plasma and brain. In a subsequent 9-month study, DHA-EE was administered at 150, 1000 and 2000mg/kg bw/day. Plasma DHA increased between 150 and 1000mg/kg bw/day but not between 1000 and 2000mg/kg bw/day and there were increases from Day 1to 92 but not between days 92 and 273. Doses >500mg/kg bw/day in the 8-week and all doses in the 9-month study resulted in DHA increases in the brain. The dose of 150mg/k gbw/day is sufficient to achieve maximal brain concentrations if DHA is administered chronically. For shorter than 6 months of supplementation, higher doses are required.