Studies on the Novel Functional Components Improving Lipid Metabolism Prepared from Marine Products

関西大

Effect of dietary protamine on lipid metabolism in rats

Protamine has been widely used as a pharmaceutical product and natural food preservative. However, few studies have been conducted to assess the beneficial function of dietary protamine. This study examined the effects of dietary salmon protamine on serum and liver lipid levels and the expression levels of genes encoding proteins involved in lipid homeostasis in the liver of rats. Groups of male Wistar rats were fed AIN93G diet containing 2% or 5% protamine. After 4 weeks of feeding these diets, markedly decreased serum and liver cholesterol (CHOL) and triacylglycerol levels were noted. Increased activity of liver carnitine palmitoyltransferase-2 and acyl-CoA oxidase, which are key enzymes of fatty acid β-oxidation in the mitochondria and peroxisomes, was found in rats fed on protamine. Furthermore, rats fed protamine showed enhanced fecal excretion of CHOL and bile acid and increased liver mRNA expression levels of ATP-binding cassette (ABC) G5 and ABCG8, which form heterodimers and play a major role in the secretion of CHOL into bile. The decrease in triacylglycerol levels in protamine-fed rats was due to the enhancement of liver β-oxidation. Furthermore, rats fed protamine exhibited decreased CHOL levels through the suppression of CHOL and bile acid absorption and the enhancement of CHOL secretion into bile. These results suggest that dietary protamine has beneficial effects that may aid in the prevention of lifestyle-related diseases such as hyperlipidemia and atherosclerosis

Effect of Superchilling (Hyo-On) Aging on the Total Bacterial Count and Concentration of Taste Components of Pork Loin

氷温を利用した肉類の長期熟成処理の有用性を評価するために、従来の熟成処理温度である4℃および氷温である−1℃で豚ロース肉の熟成処理を行い、一般生菌数、イノシン酸および遊離アミノ酸濃度に及ぼす影響を評価した。−1℃熟成処理の一般生菌数は、4℃熟成処理と比較して、熟成処理7、14および21日で有意に低下した。さらに−1℃熟成処理42日後でも、肉類が腐敗したと判断する一般生菌数である108コロニー形成単位/gには達していなかった。一方、−1℃熟成処理のイノシン酸濃度は、4℃熟成処理と比較して、緩やかな減少がみられた。腐敗の指標の1 つである一般生菌数が同等であった4℃熟成処理14日および−1℃熟成処理42日について遊離アミノ酸濃度の測定および官能評価を実施した。その結果、豚ロース肉の−1℃熟成処理42日は、4℃熟成処理14日と比較して、うま味に関わるグルタミン酸濃度の有意な上昇と嗜好型官能評価において総合的に好ましいと評価された。これらの結果より豚ロース肉の−1℃熟成処理は、4℃熟成処理よりも、一般生菌数の増殖抑制と食味性を向上させることで付加価値の向上に寄与できると考えられる。To evaluate the effects of long-term meat aging at superchilling, the total bacterial count, concentration of taste components, and palatability of pork loin were compared for samples aged at 4 °C and −1 °C. At 7, 14, and 21 days of aging, the total bacterial count of pork aged at −1℃ had significantly decreased compared to that of the sample aged at 4 ℃. Even after aging pork at −1 °C for 42 days, the total bacterial count did not reach 108 colony forming unit/g, which is generally considered to be the spoilage of meat. The concentration of inosinic acid in the pork loin aged at −1 ℃ was s decreased more slowly than that of the sample aged at 4 ℃. Free amino acid analysis and sensory evaluation were performed on the samples aged at 4 °C for 14 days and at −1 ℃ for 42 days, in which the total bacterial count was almost equivalent. Further, the glutamic acid concentration and overall palatability of pork loin sample aged at −1 ℃ for 42 days were significantly increased as compared to those of samples aged at 4 °C for 14 days. From these results, it was concluded that aging at −1 ℃ increased the added value of pork by suppressing the growth of bacteria and improving its palatability over that achieved from samples aged at 4 °C.本研究の一部は、2020年度関西大学若手研究者育成経費（個人研究）において、研究課題「熱成処理温度の違いが食肉の呈味成分の生成に関与するアミノペプチダーゼ活性に及ぼす影響」として研究費を受け、その成果を公表するものである

Effects of dietary oils prepared from the internal organs of the Japanese giant scallop (Patinopecten yessoensis) on cholesterol metabolism in obese type-II diabetic KK-Ay mice

Our research team has successfully prepared high-quality scallop oil (SCO), containing high eicosapentaenoic acid (EPA) and phospholipids (PL) from the internal organs of Japanese giant scallop (Patinopecten yessoensis) which is the largest unutilized marine resource in Japan. In this study, we prepared SCOs from scallop internal organs obtained from Mutsu (Aomori) and Uchiura (Hokkaido) bays in Japan, and named them SCO-M and SCO-U, respectively. This study aimed to investigate the effects of dietary SCO-M and SCO-U on cholesterol metabolism in obese type-II diabetic KK-Ay mice. Four-week-old male KK-Ay mice were divided into four groups. The Control group was fed with AIN93G-modified high-fat (3 wt% soybean oil + 17 wt% lard) diet, and the other groups were fed with high-fat diet, in which 7 wt% of the lard contained in the Control diet was replaced with SCO-M, SCO-U, or tuna oil (TO). After the mice had been fed with the experimental diet for 49 days, their serum, liver, and fecal lipid contents, as well as their liver messenger ribonucleic acid expression levels, were evaluated. The SCO-M and SCO-U groups were significantly decreased liver cholesterol contents compared to those of the Control and TO groups, partially through the enhancement of the fecal neutral sterol excretions and the tendency to increase the cholesterol 7α-hydroxylase expression level of the liver. These results indicated that dietary SCO-M and SCO-U exhibited cholesterol-lowering functions in the liver that can help prevent the development of lifestyle-related diseases

Chemical Composition of Salmon Ovary Outer Membrane and Its Protein Increases Fecal Mucins Content in C57BL/6J and Type 2 Diabetic/Obese KK-A y Mice

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Protective Effects of Fish (Alaska Pollock) Protein Intake against Short-Term Memory Decline in Senescence-Accelerated Mice

Dietary fish intake has proven to have health benefits in humans. n-3 polyunsaturated fatty acids (PUFAs) in fish oil (FO), especially, may provide protection against age-related cognitive disorders. Owing to the unique benefits of n-3 PUFAs, other nutrients, such as fish protein (FP), have not been well studied. To clarify the effects of FO and FP on brain function, we investigated whether FO or FP feeding can prevent age-related cognitive dysfunction in senescence-accelerated mouse-prone 10 (SAMP10) mice. The FP group maintained a better working memory compared to the control and FO groups in the Y-maze test, but not episodic memory in the novel object recognition test. To evaluate demyelination levels, we measured neurofilament H (NfH) and myelin basic protein (MBP) immunoreactivity in the hippocampus (Hipp). Axon morphology was maintained in the FP group, but not in the control and FO groups. Additionally, the percentage of positive area for double-staining with NfH/MPB was significantly higher in the Hipp of FP-fed mice than in the control (p < 0.05). These results suggest that FP intake prevents age-related cognitive dysfunction by maintaining axonal morphology in the Hipp of SAMP10 mice

Effect of exercise devised to reduce arm tremor in the sighting phase of archery.

BackgroundIn archery training, side bridges are performed in a posture similar to archery shooting for training the muscles around the shoulder joint and the shoulder girdle of the pusher.AimThe purpose of this study was to determine whether a low-tremor side-bridge exercise for 4 weeks improves bow tremor during archery movements.MethodsParticipants were 20 male college students. First, we measured the tremor during side bridges performed with trunk inclinations of 25°, 40°, 55°, and 70° using an accelerometer attached to the elbow joint and identified low-tremor side bridges. The participants were then randomly divided into intervention and non-intervention groups, and the low-tremor side bridges were performed for 4 weeks.ResultsThe effect of the intervention was determined by measuring the total tremor value using an accelerometer attached to the bow and changes in the median power frequency (MdPF) of the middle deltoid, upper trapezius, and lower trapezius. This intervention reduced the bow tremor and the median power frequency of the middle deltoid (p ConclusionsThe findings suggested that the tremor during the archery sighting phase could be reduced by performing side bridges with a specific trunk angle for a certain period of time. This intervention was also shown to reduce the intermediate frequency of the middle deltoid. The reduced tremor can shorten the sighting phase, which can facilitate injury prevention