Dietary effect of grape (Vitis vinifera) seed extract mitigates hepatic disorders caused by oxidized fish oil in rainbow trout (Oncorhynchus mykiss)

The major goal of this study was to determine the effect of grape seed extract (GSE) on liver damage in rainbow trout (Oncorhynchus mykiss) that was caused by the consumption of dietary oxidized fish oil (OFO). Rainbow trout were fed six different experimental diets coded OX-GSE 0 (OFO diet), OX-GSE 1 (OFO and 0.1% GSE), OX-GSE 3 (OFO and 0.3% GSE), GSE 0 (fresh fish oil and 0.0% GSE), GSE 1 (fresh fish oil and 0.1% GSE), and GSE 3 (fresh fish oil and 0.3% GSE) for 30 days. The lowest % hepatosomatic index (HSI) result was calculated in fish fed with OX-GSE 0 and the highest HSI was determined in fish fed with GSE 1 diets (p < 0.05). Histopathologically, hydropic degeneration in hepatocytes significantly increased OX-GSE 0 and GSE 3 compared to GSE 1 diets (p < 0.05). Deposition of lipid droplets in hepatocytes was significantly increased in OX-GSE 0 and OX-GSE 3 groups than others (p < 0.05). Liver biochemistry parameters such as superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) were significantly affected by OX and GSE treatments (p < 0.05). There were significant differences in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) among the liver enzymes analyzed in serum in OX and GSE (p < 0.05), meanwhile no difference was observed in lactate dehydrogenase (LDH) values between groups (p > 0.05). In conclusion, liver biochemistry and histopathology of rainbow trout consuming diets containing oxidized fish oil were negatively affected. However, it was determined that the supplementation of 0.1% GSE to the diet had a significant ameliorative role in these adverse effects.

Immune response and antioxidant status of broilers as influenced by oxidized vegetable oil and pomegranate peel

The experiment was designed as a 3 × 3 × 2 factorial arrangement of treatments, including (i) pomegranate peel (zero, 4%, and 8 percent), (ii) oxidized soybean oil (zero, 2%, and 4 percent), and (iii) alpha-tocopherol (zero and 200 mg/kg). Supplementation of 8% pomegranate peel in diets significantly decreased the growth performance of broiler chickens. The supplementation of 4% oxidized oil in diets significantly reduced body weight gain and Feed intake whole experimental period (p < 0.05). The results showed that supplementation of 4% pomegranate peel in the diet was associated with low aspartate transaminase (AST), alanine transaminase, and malondialdehyde (MDA). However, 4% pomegranate peel increased the total antioxidant capacity (TAC) and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. The supplemental 4% oxidized oil increased the serum AST, alanine aminotransferase (ALT), and MDA concentrations. TAC, SOD, and Catalase (CAT) activities were affected by 4% oxidized oil and alpha-tocopherol. The use of oxidized oil and vitamin E decreased MDA concentration. The serum glucose and globulin concentrations were significantly lower in the 8% pomegranate peel. The results showed that supplementation with 4% pomegranate peel in diets reduced serum low-density lipoprotein (LDL). The inclusion of 4% oxidized oil in diets reduced serum glucose and increased the blood lipid concentration such as triglyceride, cholesterol and LDL. Vitamin E supplementation reduced the serum cholesterol and LDL concentrations. The use of 8% pomegranate peel reduced red blood cell (RBC), hemoglobin, and packed cell value (PCV). The results indicated that supplementation with 8% pomegranate peel and 4% oxidized oil in diets decreased the immunoglobulin concentration in broilers. In addition, it was found that the inclusion of 4% pomegranate peel in diets resulted in higher IgG, IgM and total immunoglobulin. Pomegranate peel supplementation significantly decreased meat MDA concentration. Supplementation of 4% oxidized oil increased MDA of meat (p < 0.05). Vitamin E supplementation (200 mg/kg) significantly decreased MDA of meat (p < 0.05). Consequently, the results of this experiment showed that supplementation with 4% pomegranate peel had beneficial effects on broiler chickens. It was also found that feeding 2% oxidized oil in diets had no adverse effect on broilers.

Effects of dietary green tea (Camellia sinensis L.) supplementation on growth performance, lipid metabolism, and antioxidant status in a sturgeon hybrid of Sterlet (Huso huso ♂ × Acipenser ruthenus ♀) fed oxidized fish oil

Lipid content of diet is very susceptible to oxidation, especially when stored for a long time, so for evaluating protective effects of green tea in fish received oxidized oil, this study was done. Lipid content of diet was replaced by oxidized fish oil (OFO) in 0, 50, and 100%. Green tea extract (GTE) was added to diet in three levels, 0, 5, and 100 mg/kg giving a total of nine experimental diets. Two hundred and seventy sturgeon hybrid of Sterlet (Huso huso ♀ × Acipenser ruthenus ♂) with initial weight of 212.6 ± 0.7 g after 2 weeks adaptation randomly divided in 27 fiberglass tanks with 700 L volume. Fish were fed satiated three times daily. After 6 weeks, biometry was done to evaluate growth performance and blood samples were taken for biochemical analysis. The result showed that feeding with oxidized oil had no effects on growth. However, in fish fed GTE, growth indices improved slightly. Feeding with OFO reduced serum total cholesterol, triacylglycerol, and low-density lipoprotein, while increased high density lipoprotein. Dietary GTE moderated the effects of OFO on lipid metabolism. Feeding with the OFO increased activity of serum superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde contents. In fish received both OFO and GTE, reduced activity of serum antioxidant enzymes and malondialdehyde content was recorded in compare to fish fed only OFO. According to the result of the present study, it can be argued that feeding of sturgeon hybrid of Sterlet with OFO has negative effects on lipid metabolism and antioxidant status, whereas GTE dosages used in this study have protective effects on fish from the adverse effects of oxidized oil.

Oxidized dietary oils enhance immediate- and/or delayed-type allergic reactions in BALB/c mice

BACKGROUND

The consumption of cooking oils may exacerbate some allergic diseases. In the present study, the effects of naturally oxidized olive oil on immediate- and/or delayed-type allergic reactions were investigated in BALB/c mice.

METHODS

Mouse models of 3 types of allergic reactions: contact hypersensitivity (CHS), active cutaneous anaphylaxis (ACA), and DNFB-induced hypersensitivity, were orally administered naturally oxidized olive oil that was obtained by keeping the oil at room temperature for more than 3 years. The effects of ultraviolet ray (UV)-irradiated olive oil and other dietary oils as well as their possible oxidation products on CHS were also investigated.

RESULTS

Naturally oxidized olive oil had a high peroxide value (POV) and exacerbated CHS, ACA, and DNFB-induced hypersensitivity in a POV-dependent manner. UV-irradiated olive oil, corn oil, sesame oil and triolein had high POVs, but almost the same acid value (AV) and thiobarbituric acid-reactive substance (TBARS) level as fresh oils. Fresh olive oil and the representative oxidation product with a high AV or TBARS level had no effect on CHS, whereas all UV-irradiated oils and naturally oxidized olive oil exacerbated it.

CONCLUSIONS

Oxidized dietary oils that have high POVs exacerbated immediate- and/or delayed-type allergic reactions regardless of the different oil constituents or oxidation processes.