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1 Attractive marbled beef produced by Japanese Black cattle and 2 Wagyu: marbling and health 3 4 Takafumi GOTOH* and Nobuhiro KIMURA** 5 6 *Kuju Agricultural Research Center, Faculty of Agriculture, Kyushu University 7 8780201, Japan 8 **Kimura Animal Professional Engineers Office, Saitama 336‐0922, Japan 9 10 11 1. Prolog: Marbled beef and health 12 In Japan, highly marbled beef is required for Japanese traditional cooking 13 methods. Depending on these demands, the use of heifers and steers instead of 14 bulls and the intensive feeding system, together with the genetic ability of the 15 Japanese Black cattle, results in greater fat deposition compared with European 16 breeds. Intramuscular fat improves beef quality at least in juiciness and flavor 17 (Hornsterin & Wasserman, 1987; Wheeler, Cundiff, &Koch,1994). Therefore, 18 marbling is an accepted indicator for meat quality and is assessed in abattoirs by 19 meat graders in various countries, e.g. USA and Japan. In meat like other kinds 20 of foods, there are 3 functions of food: 1) to provide nutrition, 2) to serve 21 deliciousness, and 3) to prevent disease. Beef has these three functions. In 22 Japan, our main dish is rice. On the other hand, beef is a sub-dish. Therefore, 23 we have developed beef quality rather than quantity, on the quite different way 24 from foreign countries that meat is a main-dish. It means that we needed 25 softness and deliciousness with intramuscular fat and red part of beef to be 26 suitable for food culture like Sukiyaki. 27 Nowadays bioscience is giving new concept for health. So far, in the modern 28 life, fat has not given good image to human health. Recently fat is supposed to 29 be better for health compared with carbohydrate, especially saccharide. Fat has 30 been an important energy resource in the history of humankind made his 31 appearance on the earth. In this review, I will describe attractive Wagyu beef and 32 the relationship between marbled beef and health. 33 34 35 2. Wagyu and marbled beef 36 In Japan, we have Wagyu which has high potential to accumulate 37 intramuscular fat and produce marbled beef. After Uruguay Round (1991), the 38 ration of intramuscular fat has strongly enhanced. Nowadays, marbled Wagyu 39 beef contains more than 40% intramuscular fat, sometimes more than 60%. 40 Actually, Wagyu cattle include four types of Japanese cattle, the Black, Brown, 41 Short Horn, and Polled breeds. All have played important roles locally and in the 42 history of mixed farming, as well as the synergies that exist between cattle and 43 crops, especially rice. Farmers gradually began replacing the role of cattle as 44 draft animals with farm machinery and industrial fertilizers approximately 50 45 years ago, and in recent years, Japanese Wagyu cattle have been formed more 46 specifically for beef production, The famous brand name Wagyu includes not 47 only Japanese Black cattle produced in Japan, but also animals or even 48 crossbred Japanese Black cattle produced in foreign countries such as Australia 49 or United States America. There are numerous studies investigating the meat 50 quality, quantity, and muscle physiology of crossbreed Wagyu (Japanese Black) 51 in foreign countries (May et al., 1993; Greenwood et al., 2006, 2009; Cafe et al., 52 2006, 2009). In this review, Wagyu will be referred to as the Japanese Black. 53 High performance marbled beef production has caused Japanese Black cattle 54 to comprise the greatest share of Japan’s Wagyu cattle population (Gotoh et al., 55 2009; Albrecht et al., 2011; Gotoh et al., 2014). Bulls that have been intra-bred to 56 improve the marbling score are an important target because artificial 57 insemination is used in nearly all cattle reproduction in Japan (Figure 1). The 58 intra-beef market for marbling has been markedly enhanced after the decision 59 by the Uruguay Round allowing Japan to import foreign beef beginning in 1991. 60 61 Figure 1. Japanese Black Bull (Itofuku, Oita prefecture) (Gotoh et al., 2014) 62 63 Beef greatly contributes to human health as a food containing significant 64 protein with a high biological value. The intensive concentrated feeding system 65 necessary to produce marbled beef results in a more than 30% increase in the 66 fat tissue content of carcasses (Zenbayashi and Inayama 1987). Recently 67 intramuscular fat content often indicates more than 50%. However, it is unclear 68 whether the desirable beef produced by the Japanese Black is based only on the 69 marbling character or also on other factors. Clarification of the skeletal muscle 70 characteristics in Japanese Black cattle using scientific methods is long awaited. 71 In 2013, a total 2.64 million head of cattle for beef production were fed in 72 Japan. Approximately 1.71 million head were Japanese Black cattle (Ministry of 73 Agriculture, Forestry and Fisheries (MAFF), 2013a), and approximately 873,400 74 are Holstein cattle used in beef production. The number of households raising 75 beef cattle is slowly decreasing in Japan. The number of farmers producing beef 76 was 613,000 in 2013, but 86.5% of these farmers feed less than 50 head. The 77 mean body and carcass weights at slaughter were 725 kg and 470 kg, 78 respectively, at 26–30 months of age. In recent years, the intramuscular fat 79 percentage of beef from Japanese Black cattle averaged greater than 30% (Horii 80 et al., 2009; Albrecht et al., 2011) (Figure 2). The output of beef cattle indicated 81 about 63.2 million USD (863 ton) in 2012 (MAFF, 2013b). In recent time, Japan 82 exports Beef to foreign countries (USA, Canada, Hong Kong, Macau, Mexico, 83 New Zealand, Vietnam, Philippines, EU; since 2014). 84 85 Figure 2. Meat produced by Japanese Black steers. A: marbled beef at 12 86 thoracic vertebrae level of longissimus thoracis muscle (BMS No. 7). B: Macro 87 appearance of marbled fat depots. C: azan staining of transverse section 88 (thickness: 10μm) in the longissiumus thoracis muscle of the best grade 89 Japanese Black marbled beef. Myofiber bundles (white arrow) look like 90 islands in a sea of adipose tissue (black arrow). (Gotoh et al., Animal Science 91 Journal, 74, 339-354. 2009) D: azan staining of adipocytes. (Gotoh et al., 92 2014) 93 94 95 3. Grading of marbled beef in Japan 96 Not only Japanese Black carcasses but also those of most Japanese breeds 97 are evaluated by accredited graders from the Japan Meat Grading Association in 98 accordance with the beef carcass grading standards. There are nearly 200 99 accredited graders in Japan. Established in 1988 (Japan Meat Grading 100 Association (JMGA), 1988), the present grading system assigns both a yield 101 grade (A, B, and C) and meat quality grade (1, 2, 3, 4, and 5) (JMGA, 2014). All 102 beef carcasses in Japan are graded at the 6th to 7th rib section at least one hour 103 after ribbing. Four items are independently evaluated: beef marbling; meat color 104 and brightness; meat firmness and texture; and fat color, luster, and quality. The 105 meat quality grade of the carcass is then assigned according to the lowest grade 106 of these four items. 107 Especially regarding Beef Marbling, in 1988, the marbling levels were 108 assigned by the Beef Marbling Standard (BMS) using plastic model made from 109 silicone resin. This standard was calculated based on the circumference and 110 area percentage of marbling particles in the rib eye section (longissimus dorsi). 111 In October 2008, a new marbling standard utilizing carcass photographs 112 replaced the 1988 standard, and in March 2014, an even newer marbling 113 standard was implemented (Figure 3). Graders determine the BMS number (1 to 114 12) by comparing the actual carcass marbling and the marbling standard 115 photograph. During this process, any larger inclusions of fat at the periphery of 116 the rib eye are not considered marbling according to the Japanese grading 117 system. 118 119 120 121 122 Figure 3. Official picture standard of BMS (Beef Marbling Standard), BCS (Beef Color 123 Standard) and BFS (Beef Fat Standard) by Japan Meat Grading Association (JMGA, 2014) 124 125 126 4.Nutrients and health 127 High quality of Japanese Black beef consists of about 13% of crude protein, 128 40% of crude fat and 47% of moisture. I describe about each nutrient like the 129 followings: 130 1) Protein, amino acid of beef and related substances 131 Beef is an important food as a protein resource. it forms our body. Protein 132 especially 133 cerebrovascular disease. Positive protein intake enhances our immune 134 system. If it is short of protein, it has an attack of anemia. And finally we lose makes blood vessels flexible and prevents us from 135 our resistance against many kinds of disease and stress. Our 1/30 protein of 136 body constitution exchanges new one every day. Protein forming our body 137 consists of 20 kinds of amino acids. The amino-acid score of beef is 100. It 138 means that beef contains balanced amino acids. 139 In higher quality of Japanese Black beef, the balance of amino acid 140 composition of beef is very nice because of containing 9 kinds of essential 141 amino acids. Moreover, the ratio of absorption of beef protein to the body is 142 about 97%. It is quite nice. Amino acid basically has function of biological 143 regulation to prevent from disease. 144 Tryptophan is one of essential amino acids, from which serotonin is 145 produced. Serotonin is a neurotransmitter in brain to play role to maintain 146 tranquility. Beef contains rich tryptophan. Especially low concentration of 147 serotonin in brain is related to melancholia. Therefore tryptophan intake from 148 beef is very significant for your psychological health. Meanwhile tryptophan is 149 a material of Niacin synthesis. The insufficiency of niacin intake causes 150 headache, anorexia, constipation and diarrhea and son on. 151 Taurine, that beef abundantly contains, is one of amino acids, which play 152 role in body to enhance bile acid, make blood pressure lower and improve 153 liver function and so on. Beef contains rich taurine. 154 Leucine, which beef abundantly has, is one of essential amino acids. 155 Leucine is one of branched-chain amino acids, which is reported that it plays 156 important role to reduce muscle fatigue and improve athletic endurance. In 157 recent time, it was thought that leucine has function to suppress degradation 158 of muscle and promote synthesis of muscle. Leucine is an important to keep 159 muscle mass for us. For human health, to keep or to increase muscle mass is 160 very important because, by increasing muscle mass, basal metabolic rate 161 (BMR) is enhanced to prevent from obesity or against metabolic syndrome. 162 Carnitine which is contained in beef, is a bioactive substance to transport 163 fatty acid into mitochondria at the producing energy by burning fat in the body. 164 It is quite essential to burn body fat. 165 Myoglobin, which is related to red color of muscle, is a protein to bind iron 166 and oxygen. Myoglobin contains hemes and pigment which is responsible for 167 meat red color. In the intake of meat, iron combined with hems in myoglobin 168 of muscle can be smoothly absorbed in small intestine. We can say beef 169 contains rich and good quality iron. Therefore, beef intake is good for 170 preventing anemia. 171 172 173 2) Vitamins and minerals Beef contains relatively richer vitamin B6, B12 folate and pantothenic acid. 174 Vitamin B6 plays important role to improve metabolism of amino acid. Beef 175 relatively contains potassium, magnesium, phosphate, iron and zinc. Beef is 176 very useful as a dietary source of these vitamins and minerals. 177 178 3) Intramuscular Fat forming marbled beef: Fatty Acids 179 Fat is normally stored as neutral fat in animal body, that is a storage lipid. 180 Neutral fat is synthesized from lipid, saccharide and protein. Neutral fat is 181 digested and absorbed in the digestive tract after intake of it. The excess 182 neutral fat is stored in subcutaneous fat cells and liver as storage lipids. At the 183 hungry, neutral fat is degraded into fatty acids and glycerol. And then fatty 184 acids are utilized in each organ as an energy resource and glycerol is also 185 used in liver as an energy resource. There are some types of fatty acids: 1) 186 mono-unsaturated fatty acids (MUFAs), 2) polyunsaturated fatty acids 187 (PUFAs), and 3) saturated fatty acid. Polyunsaturated fatty acids (linoleic acid, 188 α-linolenic acid (n-3), γ-linolenic acid (n-6), Arachidonic acid and so on) has 189 many important compounds as essential fatty acids. We need to take food 190 containing PUFA. Meat like beef contains rich saturated fatty acids and 191 MUFAs (Oleic acid (n-9)). The highest ratio of fatty acids is Oleic acid as 192 MUFA in beef. Second is Stearic acid or palmitic acid as saturated fatty acids. 193 Beef also contain a little arachidonic acid (20:4(n-6)) and linoleic acid (18:3) 194 as polyunsaturated fatty acids. 195 As described previously, current beef produced by Japanese Black cattle 196 contains greater than 30% intramuscular fat. In addition to its valuable, highly 197 marbled meat, Japanese Black beef has a higher percentage of 198 monounsaturated fatty acids (MUFA) within the fat than do other breeds 199 (Yang et al. 1999a). A higher percentage of MUFA leads to a lower fat-melting 200 point, which contributes to the softness of bovine fat and favorable beef flavor, 201 and may decrease the circulating concentration of LDL cholesterol in 202 consumers (Melton et al., 1982; Rudel et al., 1995; Smith, 1994). Therefore, 203 the fatty acid composition of beef has recently become an important trait in 204 the beef industry, especially in Japanese Black cattle. 205 206 Zembayashi et al. (1995) investigated the effect of breed type, including 207 Japanese Black, and sex on the fatty acid composition of subcutaneous and 208 intramuscular lipids in finishing steers and heifers of pure Japanese Black 209 and Holstein, as well as crossbred Japanese Black, Holstein, Japanese 210 Brown, and Charolais. They reported that the Japanese Black is genetically 211 predisposed to producing carcass lipids containing higher concentrations of 212 monounsaturated fatty acids than Holstein, Japanese Brown, or Charolais 213 steers (P<0.001). Sturdivant et al. (1992) also concluded that beef from 214 purebred Wagyu cattle raised in Japan is rich in monounsaturated fatty acids. 215 Gotoh et al. (2011) compared intramuscular fatty acid composition of 216 longissimus muscle in 26-month-old Japanese Black steers and Holstein 217 steers reared and fattened using a standard fattening system with 218 considerable concentrate feed bases in a conventional Japanese fattening 219 system though normally a fattening period of Holstein cattle is short (until 220 20-22 months of age)(Table 1). In longissimus muscle, the results showed 221 higher percentage of unsaturated fatty acid in Japanese Black steers than in 222 Holstein steers (Gotoh et al., 2014). Moreover, Gotoh et al. (2011) also 223 compared the intramuscular fat content and intramuscular fatty acid 224 composition of 21 major skeletal muscles using same animals. Muscles from 225 the Japanese Black cattle contained a greater proportion of numerous fatty 226 acids, particularly C16:1, C18:1, C20:1, and monounsaturated fatty acids, 227 compared with fatty acids in the Holstein cattle (P < 0.001). In Japanese Black 228 cattle, the proportion of C18:0 and saturated FA was much lower (P < 0.001). 229 Stearoyl-CoA desaturase (SCD) was firstly identified and reported as one 230 of the genes associated with beef fatty acid composition (Taniguchi et al., 231 2004). This enzyme is responsible for converting saturated fatty acids into 232 MUFA in mammalian adipocytes. The composition of fatty acids stored in fat 233 depots reflects the earlier action of SCD on substrates such as stearic acid or 234 palmitic acid (Kim & Ntambi, 1999). Yang et al. (1999b) reported interesting 235 correlations between the SCD enzyme activity and fatty acid composition in 236 bovine adipose tissue. Although the adipogenic mechanism is extremely 237 complicated, several genes have been identified and confirmed as either 238 associated with or responsible for fatty acid composition in Japanese Black 239 cattle (Gotoh et al., 2014). 240 Sasaki et al. (2001) reported the relationship of crude fat content to lipid 241 peroxidation of beef during storage in Japanese Black beef. They prepared 242 longissimus muscle samples (fat content; 6.5-39.4%) from 27 Japanese 243 Black steers. They measured thiobarbituric acid reactive substances 244 (TBARS) and lipid hydroperoxides (LOOH). They concluded that 1) high-fat 245 beef had high preservative properties and 2) TBARS formation was 246 correlated with LOOH derived from phospholipid oxidation in the initial period 247 of storage, and the relationship was correlated directly with fat content in a 248 later period. 249 250 Table 1. Comparison of intramuscular fatty acid compositions in longissimus muscle 251 between Wagyu and Holstein steers fattened by identical conventional-fattening-system 252 253 254 255 ✝ ✝✝ Values are expressed as mean (%) ± S.E. SFA: saturated fatty acid. MUFA: monounsaturated fatty acid. ✝✝✝ PUFA: polyunsaturated fatty acid. Student’s t-test. *IMF: intramuscular fat. (Data from Gotoh et al. 2011) 256 257 Conjugated linoleic acid(CLA): In the best grade of Japanese Black beef, 258 there are more than 40% intramuscular fat. Basically intramuscular fat of beef 259 contains rich conjugated linoleic acid as a functional ingredient. Especially, 260 the ratio of conjugated linoleic acid of thigh muscle indicates 2.9 mg/g. In 261 ruminant, CLA is produced in the process that Isomerase secreted by 262 Anaerobic bacteria in microorganisms in rumens of ruminants add hydrogen 263 to linoleic acid. CLA has good effects for human health. CLA is very popular in 264 dietary supplement for overweight or obese people. Namely, CLA is supposed 265 to has a useful benefit to reduce body fat, however the evidences are still 266 insufficient. It is also supposed anti-cancer benefit (Dhiman, Nam and Ure, 267 2005). 268 Oleic acid(C18:1(n-9)): Beef contains rich oleic acid. Oleic acid is a 269 mono-unsaturated fatty acid, which can keep the level of high density 270 lipoprotein (HDL) cholesterol and reduce the level of low density lipoprotein 271 (LDL) cholesterol in blood. 272 Stearic acid (C18:0) which is one of saturated fatty acids, is reported to 273 has function to increase HDL cholesterol and to decrease LDL one in recent 274 time. 275 Arachidonic acid (C20:4 (n-6)) affects early neurological development. In 276 infants, it was reported that supplementation of arachidonic acid at 18 months 277 of age significantly improved intelligence measured by the mental 278 development index. the effect of arachidonic acid is enhanced with 279 simultaneously taking DHA. In adults, the disturbed metabolism of 280 Arachidonic acid is closely related to neurological disorders such as 281 Alzheimer's disease and Bipolar disorder (Rapoport, 2008) Arachidonic acid 282 is very important materials to form cell membrane of brain nervous. Especially, 283 arachidonic acid is not found in common plants. Therefore, we have to take 284 through dietary of meat. 285 286 287 4) Cholesterol 288 Normally cholesterol and fat has been thought to be negative factors for 289 human health. However, now it is thought that both are essential nutrients for 290 our body. If their intake is insufficient, the resistance to disease would 291 become lower, and the advance of aging would be accelerated. 292 Cholesterol is an essential structural component of all animal cell 293 membranes. Cholesterol is also an important structural lipid to make cell 294 membranes keep both membrane structural integrity and fluidity. Meanwhile 295 cholesterol is a material to synthesize steroid hormone, sex hormone, bile 296 acid and vitamin D and play important roles to maintain life. 297 298 299 4. Palatability 300 Japanese Black beef has own specific aroma. We call it “Wagyu Beef 301 Aroma”. Wagyu Beef Aroma comes from Wagyu beef cooked at 80 ℃ 302 (Matsuishi, 303 relationship between intramuscular fat content and Umami (good taste) 304 ingredients (inosinic acid and glutamine acid), Japanese Black beef 305 containing 30-35% intramuscular fat content indicated the highest value 306 summed up inosinic acid and glutamine acid (Figure 4, JMSIC, 2010). I think, 307 from the point of view of production cost, Japanese Black beef containing 308 30% intramuscular fat would be quite reasonable about palatability and 309 cost-performance. Fujimori and Okitani, 2001). Meanwhile, regarding the 310 311 312 5. How could we keep health by eating good marbled-beef? 313 Japanese Black beef contains not only protein but also so much 314 intramuscular fat. Conventionally fat intake or high calorie diet have been 315 supposed to be avoided for human health or overweight or obesity. As I 316 mentioned previously, beef includes good nutrients for forming our body, 317 keeping our health or enhancing resistance to disease. Intramuscular fat of 318 Japanese Black beef contains much MUFAs that prevent arteriosclerosis. 319 Recently it was reported that MUFAs normalize or improve lipid metabolism 320 and keep the balance in cardiac (heart) muscle (Lahey et al., 2014). 321 322 323 Figure 4. the relationship between intramuscular fat content and Umami (inosinic acid and 324 glutamine acid). Sample: beef of Japanese Black cattle, n=38. (Data of Dr. Fumiko Iida) 325 326 327 In the recent medicine as functional medicine, fat intake doesn’t have so 328 much a negative effect as a positive effect for human health (Saito, 2016). We 329 have to positively take fat containing good quality fatty acids to become healthy. 330 Of course, the balance of composition of fatty acids that we take is very 331 important. What we have to consider to reduce is to take (eat) food containing 332 much saccharide rather than fat. Especially, the excessive intake of saccharide 333 is not good for health and gives negative effects to the body. For examples, 334 unfortunately, rice, bread, noodle, cake, and root vegetables contain much 335 saccharide though they are very delicious especially Asian people. Why is 336 saccharide bad? Because excessive saccharide intake heightens the level of 337 blood glucose. On the other hand, if you eat excessive food containing much fat 338 and protein, fat and protein cannot heighten it. After becoming a higher level of 339 glucose in blood, then insulin secreted by pancreas helps glucose intake of cells, 340 and cells can generate energy from glucose. If glucose in cell is excessive, this 341 glucose goes to liver and is accumulated in the liver. However, mass of storage 342 is limited in the liver. Moreover, the excessive glucose in the liver goes outside 343 and to fat cells. it is accumulated as a neutral fat in fat cells by insulin. In this way, 344 visceral and subcutaneous fat are accumulated in the body. People finally 345 become obese. In modern society, it is thought that excessive saccharide intake 346 is one of the reasons of obesity. Such fat accumulation leads many kinds of 347 diseases like high blood presser(Hypertention), diabetes and arteriosclerosis 348 and so on. Fat cells accumulated in the human body lead inflammation in the 349 body and finally our body would not be able to control the inflammation. 350 Additionally, high level of blood glucose after meal give severe damages to 351 blood vessel (vascular endothelium) and if wound is formed on that endothelium, 352 macrophage containing lipid and calcium is accumulated in the wound. Finally, it 353 becomes fatty plaques and form thrombosis. To become healthy, it is better to 354 always keep the stable and relatively low level of insulin secretion. 355 356 On the other hand, maybe you worry about energy if you restrict to eat food 357 containing much saccharide. How can we live and work? How about energy? 358 Fortunately, our body has good functions from ancient times. We basically have 359 three ways of energy generation: 1) Glycolysis, 2) Gluconeogenesis, and 3) 360 Ketone bodies cycle (Ketogenesis). Basically mankind had eaten food 361 containing mainly fat and protein before mankind started agriculture (around 362 10,000 years ago). Mankind has started to eat carbohydrate after starting 363 agriculture, or crop production. In modern societies, we are often eating 364 excessive carbohydrate, especially much saccharide compared to our activity, 365 especially physical activity or physical labor or muscle use under the condition of 366 our modern or convenient life sytle. 367 1) The first way to generate energy is Glycolysis. Glycolysis is to produce 368 energy using glucose produced from intake of saccharide. Glycolysis is one 369 of the metabolic pathways. This pathway is the primitive metabolic pathway 370 almost organism has converts glucose into pyruvate. The free energy 371 released in this process is utilized to form the high-energy compounds ATP 372 and NADH (reduced nicotinamide adenine dinucleotide). In this pathway, 373 saccharide is used as a material. The excessive saccharide is accumulated 374 as neutral fat in fat cells or as glycogen in liver. 375 2) The second way is Gluconeogenesis. Gluconeogenesis is to produce energy 376 by producing glucose using amino acid proteolysis from muscle. In other 377 words, Gluconeogenesis is a metabolic pathway to generate glucose from 378 certain non-carbohydrate carbon substrates. By breakdown of proteins, 379 these substrates include glucogenic amino acids from breakdown of lipids, 380 they include glycerol. From other steps in metabolism they include pyruvate 381 and lactate. Gluconeogenesis is one of several main mechanisms to 382 maintain blood glucose levels, avoiding low levels of it (hypoglycemia), that 383 humans and many other animals have. If you use this system, you lose your 384 muscle. therefore you need to eat more protein like meat. 385 3) The third way is Ketone bodies cycle (Ketogenesis). Ketogenesis is to 386 generate energy by producing ketone bodies using medium-chain fatty acids 387 from neutral fat. Ketone bodies become energy. Ketone bodies are three 388 water-soluble molecules that are produced by the liver from fatty acids during 389 periods of fasting, carbohydrate restrictive diets, starvation, prolonged 390 intense exercise. These ketone bodies are converted into acetyl-CoA which 391 then enters the citric acid cycle and is oxidized in the mitochondria for energy. 392 They are therefore always released into the blood by the liver if the liver 393 glycogen stores have been depleted. In the brain, ketone bodies are also 394 used to make acetyl-CoA into long-chain fatty acids. The long-chain fatty 395 acids are not able to obtain from the blood because they are not able to pass 396 through the blood–brain barrier. In recent time, it is reported that Ketone 397 bodies play important roles of turning on the switch of longivity gene 398 expression (sirtuin 3, Shimazu et al., 2010) , antioxidant (3-Hydroxybutyric 399 acid) and keep stable appetite. 400 401 Figure 5. Three ways for generating energy from saccharide you eat, 402 muscle and neutral fat accumulated in fat cell in the human body. 403 (modified the figure that Dr. Takuji Shirasawa) 404 405 What I want to say is that we should use the second and the third ways to 406 generate energy. In Japan, some medicine doctors are recommending it 407 (Saito, 2016). If you take these two ways, you have to take protein and fat 408 rather than saccharide for getting energy. Therefore, I recommend to reduce 409 carbohydrate, especially saccharide and to increase to eat protein and fat 410 containing good quality fatty acids. It means that we can eat marbled beef to 411 generate energy and become healthy. I don’t say to stop eating saccharide, 412 however I want to say “please adjust to take saccharide according to your 413 physical activity”. In other words, once again if we can reduce to take 414 saccharide, we can eat marbled beef! It is no problem. 415 416 6. Epilog 417 I am not a medical doctor. However, food or how to eat is closely related to 418 human health and medicine. We, scientists studying beef production, should 419 know about food and how to eat based on mechanisms of our body. Protein 420 and fat 421 nutrient-source for our health. We would like to further improve the quality of 422 Japanese Black beef including reasonable production system for farmers. that Japanese Black cattle produce are very important 423 424 References 425 Albrecht, E., T. Gotoh, F. Ebara, Xu JX, T. Viergutz, G. Nuernberg, S. Maak, J. 426 Wegner. 2011. Cellular conditions for intramuscular fat deposition in 427 Japanese Black and Holstein steers. Meat Science 89: 13-20. 428 Cafe, L.M., D.W. Hennessy, H. Hearnshaw, S.G. Morris, P.L.Greenwood. 2009. 429 Consequence of prenatal and preweaning growth for feedlot growth, intake 430 and efficiency of Piedmontese and Wagyu-sired cattle. Animal Production 431 Science 49: 461-467. 432 Café, L.M., D.W. Hennessy, H. Hearnshaw, S.G. Morris, P.L.Greenwood.2006. 433 Influences of nutrition during pregnancy and lactation on birthweights and 434 growth to weaning of calves sired by Piedmontese or Wagyu bulls. Australian 435 Journal of Experimental Agriculture 46, 245-255. 436 Dhiman, T.R., S.H.Nam, and A.L.Ure. 2005. Factors affecting conjugated linoleic 437 acid content in milk and meat. Critical Reviews in Food Science and Nutrition 438 45: 463-482. 439 Gotoh, T., S. Olavanh, M. Shiota, B. Shirouchi, M. Satoh, E. Albrecht, S. Maak, J. 440 Wegner, Y. Nakamura, K. Etoh, Y. Shiotsuka, K. Hayashi, F. Ebara, T. Etoh, H. 441 Ida. 2011. Relationship between myofiber type and fatty acid composition in 442 skeletal muscles of Wagyu (Japanese Black) and Holstein cattle. The 443 proceeding of 57th International Congress of Meat Science and Technology 444 (Abstr.). 445 Gotoh, T., E. Albrecht, F. Teuscher, K. Kawabata, K. Sakashita, H. Iwamoto, J. 446 Wegner. 2009. Differences in muscle and fat accretion in Japanese Black 447 and European cattle Meat Science 82, 300-308. 448 449 Gotoh, T., H. Takahashi, T. Nishimura, K. Kuchida, H. Mannen. 2014. Meat Produced by Japanese Black Cattle and Wagyu. Animal Frontiers. 4: 46-54. 450 Greenwood, P.L., L.M. Cafe, H. Hearnshaw, D.W. Hennessy, J.M. Thopson, S.G. 451 Morris.2006. Long-term consequences of birth weight and growth to 452 weaning for carcasss, yield and beef quality characteristics of Piedmontese- 453 and Wagyu-sired cattle. Australian Journal of Experimental Agriculture 46, 454 257-269. 455 Greenwood, P.L., L.M. Cafe, H. Hearnshaw, D.W. Hennessy, S.G. Morris. 2009. 456 Consequence of prenatal and preweaning growth for yield of primal cuts 457 from 30 months of-old Piedmontese- and Wagyu-sired cattle. Animal 458 Production Science 468-478. 459 460 Gyuniku no Miryoku (in Japanese). 2010. M. Fujimaki. Japan Meat Information Service Center (JMISC) Public Interest Incorporated Association., Tokyo. 461 Horii, H, Y. Sakurai, Y. Kanbe, K. Kasai, K. Ono, T. Asada, T. Mori, M. Kobayashi, 462 A. Iguchi, M. Yamada, M. Hayashi, K. Hodate. 2009. Relationship between 463 Japanese Beef Marbling Standard numbers and intramuscular lipid in M. 464 longissimus thoracis of Japanese Black steers from 1996 to 2004. Nihon 465 Chikusan Gakkaiho 80 (1): 55-61. 466 Hornstein, I., & Wasserman, A.1987. Sensory characteristics of meat. Part 467 2-Chemistry of meat flavor. In J.F. Price &B.S.Schweigert (Eds.), The 468 science of meat and meat products ( 3rd et., pp. 329-347). Westport, CT: 469 Food and Nutrition Press. 470 Japan Meat Grading Association (JMGA). 1988. Meat Grading Standard. 471 Japan Meat Grading Association(JMGA). 2014. Beef Carcass Trading 472 Standards. pp1-16 473 Kim, Y.C., J.M. Ntambi. 1999. Regulation of stearoyl-CoA desaturase genes: 474 Role in cellular metabolism and preadipocyte differentiation. Biochemical and 475 Biophysical Research Communications 266: 1-4. 476 Lahey, R., X. Wang, A.N. Carley, E.D. Lewandowski. 2014. Dietary fat supply to 477 failing hearts determineds dynamic lipid signaling for nuclear receptor 478 activation and oxidation of stored triglyceride. Circulation 130:1790-1799. 479 480 481 MAFF. 2012. Statistics of Agriculture, forestry and fisheries . Ministry of Agriculture, Forestory and Fisheries (in Japanese ) MAFF. 2013b. Strategy of export for Beef. Ministry of Agriculture, Forestory and 482 Fisheries(in Japanese ) 483 MAFF. 2013a. Statistics. V. Livestock and Poultry, number of farm households 484 feeding livestock and number of livestock fed etc. Ministry of Agriculture, 485 Forestory and Fisheries 486 Matsuishi, M., M. Fujimori and A. Okitani. 2001. Wagyu beef aroma in Wagyu 487 (Japanese Black Cattle) beef preferred by the Japanese over imported 488 beef. Animal Science Journal 72:498-504. 489 May, S.G., C.A. Sturdivant, S.K. Lunt, R.K. Miller, S.B. Smith. 1993. Comparison 490 of sensory characteristiics and fatty acid composition between Wagyu and 491 crossbred and Angus steers. Meat Science 35, 289-298. 492 Melton, L., M. Amiri, W. Davis, R. Backus. 1982. Flavor and chemical 493 characteristics of ground beef from grass-, forage-grain- and grain-finished 494 steers. Journal of Animal Science 55: 77-87. 495 Rudel, L., S. Park, K. Sawyer. 1995. Compared with dietary monounsaturated 496 and saturated fat, polyunsaturated fat protects African green monkeys from 497 coronary artery athero-sclerosis. Arteriosclerosis, Thrombosis, and Vascular 498 Biology 15: 2101-2110. 499 500 Rapoport, S.I. 2008. Arachidonic acid and the brain. The Journal of Nutrition 138 (12): 2515–2520. 501 Saito, R. Ketogenic diet. Kodansha Ltd. Tokyo, 2016. 502 Sasaki, K., M. Mitsumoto, K. Kawabata. 2001. Relationship between lipid 503 peroxidation and fat content in Japanese Black beef Longissimus muscle 504 during storage. Meat Science 59: 407-410. 505 Shimaz, T., M.D. Hirschey, L. Hua, K.E. Dittenhafer-Reed, B. Schwer, D.B. 506 Lombard, Y. Li, J. Bunkenborg, F.W. Alt, J.M. Denu, M.P. Jacobson, 507 E.Verdin. 508 3-Hydroxy-3-Methylglutaryl CoA Synthase 2 and regulates ketone body 2010. Sirt3 deacetylates mitochondrial 509 510 511 production. Cell Metabolism, 12: 654-661. Smith, S. 1994. The animal fatty acid synthase: one gene, one polypeptide, seven enzymes. The FASEB Journal 8: 1248-1259. 512 Sturdivant, C.A., D.K. Lunt, G.C. Smith, S.B. Smith. 1992. Fatty acid composition 513 of subcutaneous and intramuscular adipose tissues and M. longissimus 514 dorsi of Wagyu cattle. Meat Science 32:449-458. 515 Taniguchi, M, T. Utsugi, K. Oyama, H. Mannen, M. Kobayashi, Y. Tanabe, A. 516 Ogino, S. Tsuji. 2004. Genotype of stearoyl-CoA desaturase is associated 517 with fatty acid composition in Japanese Black cattle. Mammalian Genome 518 15: 142-148. 519 Wheeler, T.L., Cundiff, L.V., & Koch, M. 1994. Effect of marbling degree on beef 520 palatability in Bos Taurus and Bos indicus cattle. Journal of Animal Science 521 72:3145-3151. 522 Yang, A., T.W. Larsen, H. Powell, K. Tume. 1999a. A comparison of fat 523 composition of Japanese and long-termgrain-fed Australian steers. Meat 524 Science 51: 1-9. 525 526 Yang A, T.W. Larsen, S.B. Smith, R.K. Tume. 1999b. Δ9 desaturase activity in bovine subcutaneous fatty acid composition. Lipids 34: 971-978. 527 Zembayashi, M. and M. Inayama. 1987. Fat partition and its distritbution in 528 Japanese Black, Japanese Shorthorn and Holstein steer carcass. Japanese 529 Journal of Zootechnical Science 58:381-387. 530 Zembayashi, M., K. Nishimura, D.K. Lunt, S. B. Smith. 1995. Effect of breed type 531 and sex on the fatty acid composition of subcutaneous and intramuscular 532 lipids of finishing steers and heifers. Journal of Animal Science 73: 533 3325-3332. 534 535 536 537 538 539 540 Table 1. Comparison of intramuscular fatty acid compositions in longissimus 541 muscle between Wagyu and Holstein steers fattened by identical 542 conventional-fattening-system 543 544 Figure 1. Japanese Black Bull (Itofuku, Oita prefecture) (Gotoh et al., 2014) 545 546 Figure 2. Meat produced by Japanese Black steers. A: marbled beef at 12 547 thoracic vertebrae level of longissimus thoracis muscle (BMS No. 7). B: Macro 548 appearance of marbled fat depots. C: azan staining of transverse section 549 (thickness: 10μm) in the longissiumus thoracis muscle of the best grade 550 Japanese Black marbled beef. Myofiber bundles (white arrow) look like islands 551 in a sea of adipose tissue (black arrow). (Gotoh et al., Animal Science Journal, 552 74, 339-354. 2009) D: azan staining of adipocytes. (Gotoh et al., 2014) 553 554 Figure 3. Official picture standard of BMS (Beef Marbling Standard), BCS (Beef 555 Color Standard) and BFS (Beef Fat Standard) by Japan Meat Grading 556 Association (JMGA, 2014). 557 558 Figure 4. the relationship between intramuscular fat content and Umami (inosinic 559 acid and glutamine acid). Sample: beef of Japanese Black cattle, n=38. (Data of 560 Dr. Fumiko Iida) 561 562 Figure 5. Three ways for generating energy from saccharide you eat, muscle 563 and neutral fat accumulated in fat cell in the human body.