Anti-anxiety Effect of Ovary Lipid Extracted from Skipjack Tuna (Katsuwonus pelamis) in Rats

Abstract

ABSTRACT. Using an elevated plus-maze test, we evaluated anxiety level in rats given ovary lipid extracted from Skipjack tuna (Katsuwonus pelamis; OLS). The percentage of open time was significantly higher in rats given OLS than in rats in the control group, but lower than in rats given diazepam (1.0 mg/kg body weight). Based on this fact and findings about other indicators, this study showed that OLS does not have as fast-acting and strong an anti-anxiety effect as diazepam but that continuous ingestion of OLS causes an antianxiety effect in animals. KEY WORDS: anxiety, elevated plus-maze test, ovary lipid.J. Vet. Med. Sci. 69(6): 633-636, 2007 Ovary lipid from Skipjack Tuna (Katsuwonus pelamis; OLS), extracted and purified using our patented method (JP Laid-Open No. 2004-2663, contains a large amount of docosahexaenoic acid (DHA) in the form of phospholipids such as phosphatidylcholine, phosphatidylethanolamine, and lysophosphatidylcholine. We hypothesized that if OLS ingestion relieves anxiety in companion animals, it could be useful in the treatment of problem behaviors. The elevated T-maze test is an excellent tool used for distinguishing an animal's underlying and intrinsic anxiety and/or fear from memorized behaviors [2,5,11,13,14]. Previously, we studied anxiety and/or fear using an elevated T-maze test with rats given OLS. We found that OLS shortened avoidance latency at the first trial, indicating that it has an effect against anxiety and/or fear [9]. In the present study, we evaluated the anti-anxiety effect of OLS using an elevated plus-maze test [1, 3, 4, 6-8, 12, 15], which is often used to determine anxiety level.In the previous study using an elevated T-maze test, rats were given OLS mixed as a lipid component in feed. As OLS is rich in n-3 fatty acids, the control feed was prepared to give the same energy percentage as n-3 fatty acids and the same n-6/n-3 ratio [9]. In the present study, rats were also given OLS mixed as a lipid component in feed. As this study evaluated anxiety level, however, the control group was given AIN93 and the OLS group was given AIN93, in which the lipid content was partly replaced with OLS. The animal raising period for the previous elevated T-maze test was 42 days. OLS ingestion for a shorter period decreased the rodent stress hormone corticosterone under acute stress [10]. Thus, the raising period was set at 28 days in the present study. Diazepam was used as a positive control. Observations were recorded during the first 5 min [7] (0-5 min) and then up to 15 min [8] (5-15 min) thereafter.The ovary was removed from the Skipjack tuna (Katsuwonus pelamis), washed with water, boiled, freeze-dried, powdered, and extracted with ethanol. The resultant extract was filtered and concentrated to obtain ovary lipid of Skipjack tuna (OLS).Four-week-old male Wistar rats (Japan SLC, Inc.) were used in the experiments. They were raised in an animal room maintained at a temperature of 23 ± 1°C, humidity of 55%, and a light/dark cycle of 12 hr (lighting 7:00-19:00, automatically...

Evaluation of the electromagnetic field intensity in operating rooms and estimation of occupational exposures of personnel

“…Recently, this issue has attracted the attention of researchers and there are some evidences based on biological effects of MFs with extremely low frequency (ELF) [8–10], for instance, its effects on causing leukemia [10–13], increased risk of breast cancer, and kidney cancer [14]. In addition, its harmful effects on sex hormones and fertility [4, 5, 13], bone-healing process [15, 16], wound-healing process [10], pain relief [17], hematological and biochemical parameters [9], uterus and ovaries [18], and some factors of the immune system [11–13, 19] had been investigated. These studies were almost conducted on animals, biological effects of MFs, and on human samples in accordance with the clinical trials [8].…”