Lard Diet Group Research Articles

MP20-17 LARD DIET PROMOTES PROSTATE CANCER PROGRESSION THROUGH MODULATING GUT MICROBIOTA AND INTRATUMORAL LIPID METABOLISM

You have accessJournal of UrologyCME1 Apr 2023MP20-17 LARD DIET PROMOTES PROSTATE CANCER PROGRESSION THROUGH MODULATING GUT MICROBIOTA AND INTRATUMORAL LIPID METABOLISM Hiromi Sato, Shintaro Narita, Yoshiko Takahashi, Masanori Ishida, Mizuki Kobayashi, Soki Kasima, Ryohei Yamamoto, Taketoshi Nara, Mingguo Huang, Kazuyuki Numakura, Mitsuru Saito, Toshiaki Yoshioka, and Tomonori Habuchi Hiromi SatoHiromi Sato More articles by this author , Shintaro NaritaShintaro Narita More articles by this author , Yoshiko TakahashiYoshiko Takahashi More articles by this author , Masanori IshidaMasanori Ishida More articles by this author , Mizuki KobayashiMizuki Kobayashi More articles by this author , Soki KasimaSoki Kasima More articles by this author , Ryohei YamamotoRyohei Yamamoto More articles by this author , Taketoshi NaraTaketoshi Nara More articles by this author , Mingguo HuangMingguo Huang More articles by this author , Kazuyuki NumakuraKazuyuki Numakura More articles by this author , Mitsuru SaitoMitsuru Saito More articles by this author , Toshiaki YoshiokaToshiaki Yoshioka More articles by this author , and Tomonori HabuchiTomonori Habuchi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003245.17AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Lard diet (LD) is a risk factor for prostate cancer (PCa) progression. The role of dietary dysbiosis in the development of PCa is largely unknown, even though it has recently become clear that it plays a significant role in progression of many cancers. Herein, we performed a comprehensive gut microbiome and intratumoral mRNA omics analyses to analyze targetable molecules involved in LD-induced PCa progression via gut microbial alteration. METHODS: Pb-Cre; Pten (fl/fl) transgenic mice and C57BL6 mice subcutaneously inoculated with TRAMP-C2 PCa cells were fed with a LD rich in saturated fatty acid (SFA) or fish- oil diet (FOD) rich in polyunsaturated fatty acid. We obtained fecal and prostate/subcutaneous tumor samples. Using 16S rRNA gene amplicon sequencing, we compared the diversity and relative abundance of gut microbiota. We performed a cDNA microarray to assess the mRNA expression in the mouse PCa tissue. RESULTS: More weight and prostate/subcutaneous tumor volume were gained by the LD-fed mice in two mouse models compared to the FOD-fed mice. In an integrated analysis of the two models, the LD group and the FOD group formed different gut microbial clusters. According to microbiome analysis, order Lactobacillales was relatively more abundant in the FOD group than in the LD group, and order Clostridiales was enriched in the LD group compared to the FOD group. The proportion of order Lactbacillales in the gut was negatively associated with the body weight and prostate weight of the mice. In microarray analysis, we found the modulation of lipid metabolism and cholesterol biosynthesis pathways with 10 significantly modulated genes including sphingosine 1-phosphate receptor 2 (S1PR2) and low-density lipoprotein receptor (LDLR) in PCa tissues. Of these genes, S1PR2 was highly correlated with the abundance of order Lactobacillales in the mouse gut. Moreover, PCa patients with a higher Gleason score (≥8) and a higher body mass (BMI) index had significantly lower S1PR2 RNA levels in human prostatic specimens than those with a Gleason score ≤ 7 and lower BMI. CONCLUSIONS: SFA may accelerate PCa progression by altering particular gut microbial species and lipogenic genes in PCa. Therapeutics with alteration of gut microbiota and candidate genes involved in diet-induced PCa progression may be attractive in PCa. Source of Funding: GlaxoSmithKline plc © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e282 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hiromi Sato More articles by this author Shintaro Narita More articles by this author Yoshiko Takahashi More articles by this author Masanori Ishida More articles by this author Mizuki Kobayashi More articles by this author Soki Kasima More articles by this author Ryohei Yamamoto More articles by this author Taketoshi Nara More articles by this author Mingguo Huang More articles by this author Kazuyuki Numakura More articles by this author Mitsuru Saito More articles by this author Toshiaki Yoshioka More articles by this author Tomonori Habuchi More articles by this author Expand All Advertisement PDF downloadLoading ...

Diet-Induced Thermogenesis Is Lower in Rats Fed a Lard Diet Than in Those Fed a High Oleic Acid Safflower Oil Diet, a Safflower Oil Diet or a Linseed Oil Diet

The objectives of the present study were to examine the effects of dietary fats differing in fatty acid composition on diet-induced thermogenesis, sympathetic activity in brown adipose tissue and body fat accumulation in rats. Rats were meal-fed for 12 wk an isoenergetic diet based on lard, high oleic acid safflower oil, safflower oil or linseed oil, and norepinephrine turnover rates in brown adipose tissue were then estimated. Whole-body oxygen consumption after the meal indicated that diet-induced thermogenesis was significantly lower in rats fed the lard diet than in those fed the other diets. The norepinephrine turnover rate in the interscapular brown adipose tissue was also significantly lower in the lard diet group than in the other diet groups. The carcass fat content was significantly higher in the lard diet group than in the other diet groups, whereas the abdominal adipose tissue weights were the same in all diet groups. These results suggest that the intake of animal fats rich in saturated fatty acids, compared with the intake of vegetable oils rich in monounsaturated or polyunsaturated fatty acids, decreases diet-induced thermogenesis by a decline of sympathetic activity in brown adipose tissue, resulting in the promotion of body fat accumulation.

Effects of different diets used to induce obesity/metabolic syndrome on bladder function in rats.

Preclinical and human studies on the relationship between obesity/metabolic syndrome (MetS) and lower urinary tract dysfunction (LUTD) are inconsistent. We compared the temporal effects of feeding four different diets used to induce obesity/MetS, including 60% fructose, 2% cholesterol +10% lard, 30% fructose + 20% lard, or 32.5% lard diet, up to 42 wk, on metabolic parameters and bladder function in male Sprague-Dawley rats. Rats fed a 30% fructose + 20% lard or 32.5% lard diet consumed less food (grams), but only the 32.5% lard diet group took in more calories. Feeding rats a 60% fructose or 30% fructose + 20% lard diet led to glucose intolerance and increased blood pressure. Higher body weight and increased cholesterol levels were observed in the rats maintained on a 2% cholesterol +10% lard diet, whereas exposure to a 32.5% lard diet affected most of the above parameters. Voiding behavior measurement showed that voiding frequency and the total voided volume were lower in the experimental diet groups except for the 30% fructose + 20% lard group. The mean voided volume was lower in the 30% fructose + 20% lard and 32.5% lard groups compared with the control group. Cystometric analysis revealed a decreased bladder capacity, mean voided volume, intermicturition interval, and compliance in the 32.5% lard diet group. In conclusion, experimental diets including 60% fructose, 30% fructose + 20% lard, or 2% cholesterol + 10% lard diet differently affected physiological and metabolic parameters and bladder function to a limited extent, while exposure to a 32.5% lard diet had a greater impact.

PD46-10 SATURATED FATTY ACID PROMOTES PROSTATE CANCER DEVELOPMENT WITH TUMOR INFILTRATING REGULATORY T CELL ALTERATION IN A PTEN-DEFICIENT MOUSE MODEL

You have accessJournal of UrologyCME1 May 2022PD46-10 SATURATED FATTY ACID PROMOTES PROSTATE CANCER DEVELOPMENT WITH TUMOR INFILTRATING REGULATORY T CELL ALTERATION IN A PTEN-DEFICIENT MOUSE MODEL Hiromi Sato, Shintaro Narita, Yoshiko Takahashi, Masanori Ishida, Soki Kasima, Ryohei Yamamoto, Atsushi Koizumi, Taketoshi Nara, Mingguo Huang, Kazuyuki Numakura, Mitsuru Saito, Toshiaki Yoshioka, and Tomonori Habuchi Hiromi SatoHiromi Sato More articles by this author , Shintaro NaritaShintaro Narita More articles by this author , Yoshiko TakahashiYoshiko Takahashi More articles by this author , Masanori IshidaMasanori Ishida More articles by this author , Soki KasimaSoki Kasima More articles by this author , Ryohei YamamotoRyohei Yamamoto More articles by this author , Atsushi KoizumiAtsushi Koizumi More articles by this author , Taketoshi NaraTaketoshi Nara More articles by this author , Mingguo HuangMingguo Huang More articles by this author , Kazuyuki NumakuraKazuyuki Numakura More articles by this author , Mitsuru SaitoMitsuru Saito More articles by this author , Toshiaki YoshiokaToshiaki Yoshioka More articles by this author , and Tomonori HabuchiTomonori Habuchi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002614.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Recent studies reported that gut microbiota plays an important role in systemic immune response and is involved in cancer development. Herein, using a Pten-deficient mouse model, we assessed the role of systematic and local inflammation, tumor immune microenvironment and gut microbiota profiles on specific-fat diet-induced PCa development. METHODS: Immunocompetent Pten-deficient mice were fed with isocaloric diets that differed in fat composition (lard or fish oil), and were sacrificed at 28 weeks. Using 16S rRNA gene amplicon sequencing, the gut microbiota was profiled for the phylum levels. We performed flow cytometry analyses and quantitative RT-PCR to evaluate the number of prostate infiltrating immune cells and expression of immune cell markers in the prostates of the mice. Antibiotic-treated mice were developed to assess the impact of gut microbiome on fat-diet induced PCa development. RESULTS: The lard diet (LD) -fed mice gained more weight and prostate volume than the fish-oil diet (FOD) -fed mice. We noticed invasive PCa in the LD group (3 of 10 mice) alone, and the Ki67 positivity in the prostates of the LD group was significantly higher than that of the FOD mice (p<0.01). The mean serum LPS level tended to be higher in the LD group (p=0.09), and significantly correlated with mouse weight (p<0.01, r=0.78). The two dietary groups showed markedly different gut microbiota profiles, and the proportion of the Proteobacteria phylum in the LD group was significantly higher than in the FOD group (p=0.02). The mean number of regulatory T cells in the prostates of the LD group was significantly higher than the FOD group (p=0.03). Larger growth of the prostate, higher mean serum LPS level and higher expression of Foxp3 in the prostates of the LD group than those of the FOD group were observed, whereas the microbiota ablation using antibiotics-treated mice abrogated the differences. CONCLUSIONS: LD accelerates PCa development through elevated serum LPS, alteration of gut microbiota and regulatory T cell infiltration in tumor microenvironment in an engineered mouse model of PCa. Immune cell modulation in tumor microenvironment on basis of diet and/or gut microbial changes may be a novel treatment strategy for PCa. Source of Funding: nothing © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e791 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hiromi Sato More articles by this author Shintaro Narita More articles by this author Yoshiko Takahashi More articles by this author Masanori Ishida More articles by this author Soki Kasima More articles by this author Ryohei Yamamoto More articles by this author Atsushi Koizumi More articles by this author Taketoshi Nara More articles by this author Mingguo Huang More articles by this author Kazuyuki Numakura More articles by this author Mitsuru Saito More articles by this author Toshiaki Yoshioka More articles by this author Tomonori Habuchi More articles by this author Expand All Advertisement PDF DownloadLoading ...

Abstract 2662: Cellular retinoic acid-binding protein 2 enhances saturated fatty acid-induced prostate cancer progression

Abstract Introduction: Epidemiological evidence suggests that saturated fatty acid has a role in prostate cancer progression; however underlying mechanisms remain unknown. Here, we conducted a comprehensive omics analysis to investigate candidate molecules associated with saturated fat-induced prostate cancer (PCa) progression. Methods: TRAMP-C2 cells were subcutaneously injected into two groups of C57BL6 mice: the lard diet (LD) group, which was fed isocaloric saturated fatty acid, and the fish oil diet (FOD) group, which was fed polyunsaturated fatty acid. We performed an oligonucleotide microarray with the Affymetrix Gene Chip Mouse Gene 2.0 ST Array and proteomic analysis using nano-liquid chromatography-tandem mass spectrometry using xenograft tumors and validated the result by western blotting and immunohistochemistry. The cell proliferation and mRNA levels of CRABP2 in two PCa cell lines cultured with mice serum were assessed by performing an MTT cell assay and quantitative real-time polymerase chain reaction. The effect of CRABP2 on survival in PCa patients was evaluated by reviewing data from The Cancer Genome Atlas database. Results: The mean body weight of the LD group tend to be higher than that of the LD group (p = 0.066). Subcutaneous tumor volume were significantly higher in the LD group than the FOD group (p = 0.044). One hundred fifty-three up- and 120 downregulated genes and 734 up- and 1514 downregulated proteins with &amp;gt;1.5-fold changes were identified in the LD group. Multi-omics approach showed 32 candidate molecules which have the potential to be highly associated with saturated fatty acid diet-induced prostate cancer progression. In the molecules, CRABP2 was selected as the most candidate molecule. The higher expression of CRABP2 in xenografts of the LD group was validated by western blotting and immunohistochemistry. PCa cells cultured in a medium containing LD mouse serum were associated with significantly higher cell proliferation rates and higher CRABP2 expression levels than those of PCa cells cultured in FOD. Overall survival significantly worse in the patients with altered CRABP2 than in those with unaltered CRABP2 (p &amp;lt; 0.001). Conclusion: Saturated fatty acid-accelerated PCa growth was enhanced by CRABP2. CRABP2 may be a key regulator of diet-induced PCa progression and a novel therapeutic target for PCa. A low saturated fat diet in males may be encouraged. Citation Format: Hiromi Sato, Shintarao Narita, Masanori Ishida, Soki Kashima, Ryohei Yamamoto, Atsushi Koizumi, Taketoshi Nara, Kazuyuki Numakura, Mitsuru Saito, Shigeru Satoh, Naoshi Dohmae, Tomonori Habuchi. Cellular retinoic acid-binding protein 2 enhances saturated fatty acid-induced prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2662.

Diet Rich in Lard Promotes a Metabolic Environment Favorable to Trypanosoma cruzi Growth.

Background: Trypanosoma cruzi is a protozoan parasite that causes Chagas disease and affects 6–7 million people mainly in Latin America and worldwide. Here, we investigated the effects of hyperlipidic diets, mainly composed of olive oil or lard on experimental T. cruzi infection. C57BL/6 mice were fed two different dietary types in which the main sources of fatty acids were either monounsaturated (olive oil diet) or saturated (lard diet).Methods: After 60 days on the diet, mice were infected with 50 trypomastigote forms of T. cruzi Colombian strain. We evaluated the systemic and tissue parasitism, tissue inflammation, and the redox status of mice after 30 days of infection.Results: Lipid levels in the liver of mice fed with the lard diet increased compared with that of the mice fed with olive oil or normolipidic diets. The lard diet group presented with an increased parasitic load in the heart and adipose tissues following infection as well as an increased expression of Tlr2 and Tlr9 in the heart. However, no changes were seen in the survival rates across the dietary groups. Infected mice receiving all diets presented comparable levels of recruited inflammatory cells at 30 days post-infection but, at this time, we observed lard diet inducing an overproduction of CCL2 in the cardiac tissue and its inhibition in the adipose tissue. T. cruzi infection altered liver antioxidant levels in mice, with the lard diet group demonstrating decreased catalase (CAT) activity compared with that of other dietary groups.Conclusions: Our data demonstrated that T. cruzi growth is more favorable on tissue of mice subjected to the lard diet. Our findings supported our hypothesis of a relationship between the source of dietary lipids and parasite-induced immunopathology.

The effects of different high-fat (lard, soybean oil, corn oil or olive oil) diets supplemented with fructo-oligosaccharides on colonic alkaline phosphatase activity in rats.

We recently reported that fermentable non-digestible carbohydrates including fructo-oligosaccharides (FOS) commonly elevate colonic alkaline phosphatase (ALP) activity and the expression of IAP-I, an ALP gene, in rats fed a high-fat (HF) diet, and also elevate gut mucins and modulate gut microbiota. This study aims to investigate whether dietary fat types influence the effect of FOS on colonic ALP activity and the luminal environment in HF-fed rats. Male Sprague-Dawley rats were fed a diet containing 30% soybean oil, corn oil, olive oil or lard with or without 4% FOS for 2weeks. Colon ALP activity, gene expression, and gut luminal variables including mucins and microbiota were measured. In the lard diet groups, dietary FOS significantly elevated colonic ALP activity and the expression of IAP-I. The elevating effect of FOS on colonic ALP activity was also observed in the olive oil diet groups, although here the IAP-I expression was not changed. However, the soybean oil and corn oil diet groups did not exhibit the elevating effect of FOS on colon ALP. Fecal ALP and mucins were significantly elevated by dietary FOS regardless of dietary fat types, and the effect of FOS was prominent in the lard diet groups. The number of Lactobacillus spp. observed in fecal matter was significantly increased by dietary FOS in the lard and olive oil diet groups, but not in the soybean oil and corn oil diets groups. This study suggests that dietary fat types may change the effect of FOS on the colonic luminal environment including the ALP activity in rats fed a high-fat diet.

Mfsd2a and Glut1 Brain Nutrient Transporters Expression Increase with 32-Week Low and High Lard Compared with Fish-Oil Dietary Treatment in C57Bl/6 Mice

BackgroundDiet-mediated alterations of critical brain nutrient transporters, major facilitator super family domain-containing 2a (Mfsd2a) and glucose transporter 1 (Glut1), have wide reaching implications in brain health and disease. ObjectiveThe aim of the study was to examine the impact of long-term low- and high-fat diets with lard or fish oil on critical brain nutrient transporters, Mfsd2a and Glut1. MethodsEight-week-old male C57BL/6 mice were fed 1 of the following 4 diets for 32 wk: 10% of kcal from lard, 10% of kcal from fish oil, 41% of kcal from lard, or 41% of kcal from fish oil. Body weight and blood chemistries delineated dietary effects. Cortical and subcortical Mfsd2a and Glut1 mRNA and protein expression were evaluated, with other supportive nutrient-sensitive targets also assessed for mRNA expression changes. ResultsFish-oil diets increased cortical Mfsd2a mRNA expression compared with lard diets. Subcortical Mfsd2a mRNA expression decreased as the percentage of fat in the diet increased. There was an interaction between the type and percentage of fat with cortical and subcortical Mfsd2a and cortical Glut1 protein expression. In the lard diet groups, protein expression of cortical and subcortical Mfsd2a and cortical Glut1 significantly increased as fat percentage increased. As the fat percentage increased in the fish-oil diet groups, protein expression of cortical and subcortical Mfsd2a and cortical Glut1 did not change. When comparing the fish-oil groups with 10% lard, cortical Mfsd2a protein expression was significantly higher in the 10% and 41% fish-oil groups, whereas cortical Glut1 protein expression was significantly higher in only the 10% fish-oil group. A positive correlation between cortical peroxisome proliferator–activated receptor γ mRNA expression and Mfsd2a protein expression was shown. ConclusionCorresponding to chronic dietary treatment, an interaction between the type of fat and the percentage of fat exists respective to changes in brain expression of the key nutrient transporters Mfsd2a and Glut1.

Fish Oil Suppresses Body Fat Accumulation in Zebrafish.

Zebrafish is an often used model of vertebrate lipid metabolism. In this article, we examined the effects of diets rich in fish oil, a dietary fat that has been shown to have antiobesity effects in mammals, or lard on body fat accumulation in zebrafish. Adult female zebrafish were fed a high-fat diet containing 20% (w/w) fish oil or lard for 4 weeks. Fish in the fish oil diet group had less body fat accumulation compared with those in the lard diet group. In the intestine, expression of genes for the alpha (hadhaa) and beta (hadhb) subunits of the beta-oxidation enzyme hydroxyacyl-Coenzyme A dehydrogenase/3-ketoacyl-Coenzyme A thiolase/enoyl-Coenzyme A hydratase was significantly increased in the fish oil diet group compared with the lard diet group (p < 0.05). In the liver, expression of the gene for fatty acid synthase (fasn) was significantly decreased in the fish oil diet group compared with the lard diet group (p < 0.05). These results suggest that the mechanisms underlying the antiobesity effect of fish oil are similar in zebrafish and mammals.

Effect of Plant- and Fish-Oil Derived n-3 Polyunsaturated Fatty Acids on Counteraction of n-3 Fatty Acid Shortage in Adult Rats Fed a Lard Diet

These studies aimed to compare the effects of alpha-linolenic acid (ALA)+eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) on plasma-lipid concentrations and preferential fat intake of rats fed a lard diet (LD). Each of 2 groups of 4-wk-old male rats was used in studies 1 and 2. In studies 1 and 2, two groups of rats received the LD (LD group) and the fish-oil diet (FD; FD group), and the LD and the perilla-oil diet (PD; PD group), respectively (dietary treatment period). After 6 wk, 6 rats per group were sacrificed. The remaining rats in studies 1 and 2 were placed on a self-selection regimen of the LD and the FD, and the LD and the PD, respectively, for 3 wk (self-selection period). After the dietary treatment period, plasma lipid concentrations in the FD group were lower than those in the LD group. However, no significant difference in the concentrations was observed between the LD group and the PD group. At the beginning of the self-selection period, the ratio of the FD intake of the LD group was higher than that of the FD group. As the the ratio of the LD group decreased and that of the FD group increased no significant difference in the ratio was observed after the 9th day during the self-selection period. No significant difference in the ratio of the PD intake was observed between the LD group and the PD group during the self-selection period. Thus, although the FD decreased plasma lipid concentration and increased the preferential FD intake of the LD group at the beginning of the self-selection period, the PD did not. Our studies clearly show that dietary EPA+DHA and ALA have different physiologic effects.

妊娠・授乳期ラットにおけるラード及び魚油添加飼料の摂取が仔ラットの油脂摂取嗜好と成長に及ぼす影響

To investigate the influence of fat-feeding dams on the food choice and the growth of their pups after weaning two groups of dams were fed a lard diet (LD) or a fish oil diet (FD) during pregnancy and lactation. Immediately after weaning, all pups were placed on two-choice diet program of the LD and the FD for 3 weeks. Although dietary intake during lactation by dams fed the LD was higher than that by dams fed the FD, at the end of lactation, body weight of the LD group was lower than that of the FD group. Body and perirenal fat tissue weights, and plasma leptin and lipid concentrations in suckling pups of dams fed the LD were higher than those in suckling pups of dams fed the FD. These findings indicate that amount of energy transferred to suckling pups from dams fed the LD was higher than that transferred to suckling pups from dams fed the FD. At the beginning of the self-selection period, no significant difference in the amount of the LD and the FD intake was observed between both groups of pups. However, in both groups of pups, the ratio of the LD intake increased and that of the FD decreased from day 3 to 6. After day 6, the ratio of the LD and the FD intake of the pups was about 80% and 20%, respectively. S : M : P and n-3FA : n-6FA in the diet that both groups of pups self-selected after day 6 was 3.3 : 3.9 : 3.0 and 2.9 : 1.0, respectively. These data led us to conclude that rat have an ability to consume essential fatty acid adequately through internal fatty acid metabolism.

Effect of Erabu Sea Snake (Laticauda semifasciata) Lipids on the Swimming Endurance of Mice

Background/Aim: This study was designed to investigate the effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance of mice. Method: Twelve-week-old male Crlj: CD-1 (ICR) mice were fed one of three experimental diets containing 6% lard, fish oil or sea snake lipids for 16 weeks. Swimming exercise was conducted in an acrylic plastic tank filled with 25 cm of water maintained at 23°C. Every 4 weeks, the mice were made to perform swimming exercises with loads attached to their tails, corresponding to approximately 1 or 2% of their body weights. Results: The group fed the sea snake lipid diet exhibited significantly improved swimming endurance compared with the lard diet group (p < 0.05); however, this result was not observed in the fish oil diet group. In the sea snake lipid diet group, plasma and muscle lactates were significantly lower, and plasma glucose and muscle glycogen were significantly higher than in the lard diet group (p < 0.05). Conclusion: These results suggest that the intake of sea snake lipids enhanced the swimming endurance of the mice by delaying the accumulation of lactate during swimming exercise.

Effect of Erabu Sea Snake (Laticauda semifasciata) Lipids on the Swimming Endurance of Aged Mice

The effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance was investigated in aged mice. Fifty three-week-old male Crlj:CD-1 (ICR) mice were fed one of three experimental diets containing either 6% lard, 6% fish oil, or 6% sea snake lipids for 16 wk. The swimming exercise was carried out in an acrylic plastic tank filled with 25 cm of water maintained at 23(o)C. Swimming times to exhaustion were measured with a load of 2% of their body weights attached to the tails of the mice. The swimming times to exhaustion of the group that were fed the sea snake lipid diet tended to be longer than those of the lard diet group, and were significantly improved compared with the fish oil diet group (p<0.05). The plasma and muscle lactate levels were significantly lower in the sea snake lipid diet group than in the lard and fish oil diet groups (p<0.05). The liver glycogen and plasma glucose levels of the sea snake lipid diet group did not differ markedly from those of the lard diet group (p>0.05), and were significantly higher than those of the fish oil diet group (p<0.05). These results suggest that an intake of sea snake lipids but not the fish oil, which is also rich in n-3 polyunsaturated fatty acids (n-3 PUFAs), is useful for improving the swimming endurance of aged mice by attenuating lactate production and/or enhancing lactate clearance during swimming exercise, and the n-3 PUFAs contained in the sea snake lipids did little or nothing for this improved endurance.

Effects of Dietary Herring Roe Lipids on Plasma Lipid, Glucose, Insulin, and Adiponectin Concentrations in Mice

The aim of this study was to evaluate the effects of dietary Kazunoko (salted herring roe) lipids, which contain large amounts of cholesterol, phosphatidylcholine, and n-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), on lipid and glucose metabolism in mice. Male Crlj:CD-1 (ICR) mice were fed one of four experimental diets which contained 6% lard, 1% Kazunoko lipids + 5% lard, 3% Kazunoko lipids + 3% lard, and 6% Kazunoko lipids for 12 weeks. Plasma total cholesterol, triacylglycerol, phospholipid, and glucose concentrations were significantly lower in the 3% and 6% Kazunoko lipid diet groups than in lard and 1% Kazunoko lipid diet groups (p < 0.05). Plasma adiponectin concentrations of mice fed the 6% Kazunoko lipid diet were higher than those of animals fed the lard diet group. These results suggest that EPA and DHA rather than cholesterol in the Kazunoko lipids influence the plasma total cholesterol level. The constituent Kazunoko lipids may not only decrease the levels of plasma lipids but also decrease glucose concentrations by enhancing plasma adiponectin levels in mice.

Reduction in Plasma Glucose after Lipid Changes in Mice Fed Fish Oil, Docosahexaenoic Acid, and Eicosapentaenoic Acid Diets

Background/Aim: Effects of the dietary docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and fish oil on weekly changes in plasma glucose, total cholesterol, triacylglycerol, and phospholipid concentrations of male Crlj:CD-1 mice were investigated. Method: Animals were fed five different experimental diets which contained 6.0% lard (lard diet), 6.0% fish oil (fish oil diet), 1.5% DHA-ethyl ester + 4.5% lard (DHA diet), 0.4% EPA-ethyl ester + 5.6% lard (EPA diet), and 1.5% DHA-ethyl ester + 0.4% EPA ethyl ester + 4.1% lard (DHA+EPA diet) for 17 weeks. Glucose and lipid concentrations in plasma collected at weeks 0, 1, 2, 4, 6, 8, 12, and 16 were measured. Results: Plasma phospholipid concentrations were significantly lower in mice fed the fish oil and DHA+EPA diets than in those fed the lard diet at week 2. Plasma total cholesterol and glucose concentrations were significantly lower in the fish oil diet group than in the lard diet group at weeks 6 and 8, respectively. Conclusion: These results indicate that the decreases in plasma glucose concentrations in response to intakes of DHA and EPA in mice take place over a longer period of time than similar decreases in the plasma lipid concentrations.

Effect of Lipids Extracted from a Salted Herring Roe Food Product on Maze-Behavior in Mice

Male mice (11 mo old) were fed 5% lard, fish oil, or Kazunoko (salted fish roe product) lipids for 4 mo to investigate their effects on maze behavior. The time required and distance traveled to reach the maze exit, and number of times that a mouse strayed into blind alleys in the maze, and the fatty acid compositions of brain lipids after the maze-behavior experiment were measured. The Kazunoko lipid group showed a significant improvement in all three parameters compared with the lard diet group, but the fish oil group showed only a significant decrease in the number of times that a mouse strayed into blind alleys compared with the lard diet group. The mice in the fish oil and Kazunoko lipid groups had significantly lower levels of arachidonic acid and higher percentages of docosahexaenoic acid in brain lipids compared with animals in the lard group. The mice in the Kazunoko lipid group had significantly lower levels of arachidonic acid in brain lipids than those in the fish oil group but the percentages of docosahexaenoic acid were not significantly different between these two diet groups. Our results suggest that an intake of Kazunoko lipids may suppress the percentage of n-6 fatty acids in brain lipids and this diet can be even more effective than fish oil as a supplement to improve learning capacity in mice.

Serum Triiodothyronine Concentration and Na+,K+-ATPase Activity in Liver and Skeletal Muscle Are Influenced by Dietary Fat Type in Rats

It has been shown previously that dietary fat type influences body fat accumulation in rats. The effects of dietary fat type on serum thyroid hormone, activity of Na+,K+-ATPase and lipoprotein lipase were studied. Rats were fed an experimental diet containing lard, high oleic safflower oil, safflower oil or linseed oil for 12 wk. Carcass fat content was significantly higher in rats fed the lard diet than in those fed the other diets. However, intra-abdominal adipose tissue weights were not affected by type of dietary fat. The serum triiodothyronine concentration and the activity of Na+,K+-ATPase in the liver and skeletal muscle were significantly lower in the lard diet group than in the other diet groups. The lipoprotein lipase activity of abdominal subcutaneous fat was significantly higher in rats fed the lard diet than in rats fed the other diets, but the activity of lipoprotein lipase in intra-abdominal fat was not significantly different. These results suggest that the intake of lard, compared with the intake of the vegetable oils, may decrease Na+,K+-ATPase activity in the liver and skeletal muscle by lowering serum triiodothyronine concentration, resulting in the promotion of body fat accumulation.