Eisaku Tsuneishi

Histological contribution of collagen architecture to beef toughness.

The relationship between shear-force value and collagen architecture of connective tissue of the longissimus thoracis (LT) muscle of Japanese Black (n = 10) and Brown (Kumamoto) (n = 5) steers (body weight: 688.4 +/- 8.6 kg as average and standard error) was investigated. There were negative correlations between the shear-force value and lipid content (n = 15, R(2)= 0.3709, P < 0.01) and protein content and lipid content (n = 15, R(2)= 0.6748, P < 0.01). Shear-force value and collagen content (n = 15, R(2)= 0.4344, P < 0.01) were positively correlated. In scanning electron microscopic photographs of the macerated preparation, the perimysium of the high-lipid LT muscle was broken down compared with the low-lipid LT muscle. The endomysium in all LT muscle fibers showed similar architecture. The fine surface cover of reticular collagen fibers around an adipocyte was observed in the high-lipid LT muscle perimysium. These results suggested that the shear-force value of the LT muscle was related to change in collagen architecture and of the perimysium in particular.

Effects of feeding level of milk replacer on body growth, plasma metabolite and insulin concentrations, and visceral organ growth of suckling calves

The objective was to evaluate effects of feeding level of milk replacer on body growth, plasma metabolite and insulin concentrations, and allometric growth of visceral organs in suckling calves. Holstein bull calves (n = 8; 3-4 days of age) were fed either a low amount (average 0.63 kgDM/day, LM) or high amount (average 1.15 kgDM/day, HM) of high protein milk replacer until they were slaughtered at 6 weeks of age. Body weight (BW) at 4, 5, and 6 weeks of age, feed intake, average daily gain, and feed efficiency were higher in the HM than LM calves. The HM group had higher plasma glucose at 3 and 4 weeks of age and insulin levels after the age of 4 weeks compared with LM calves whereas no effect was detected on plasma nonesterified fatty acid or urea nitrogen concentrations. The HM calves had greater empty body weight (EBW), viscera-free BW and most of the organs dissected than LM calves. Relative weights (% of EBW) of liver, spleen, kidneys, and internal fat were higher, whereas head and large intestine was lower in HM than LM calves. The results suggest that increased milk feeding levels would accelerate the growth of the body and specific organs.

Pulsatile growth hormone secretion, circulating insulin-like growth factor-1 concentration and cellular density of somatotrophs differ between Wagyu and Holstein steers

Japanese Black cattle (Wagyu), deposit much higher amounts of intramuscular fat, known as marbling, than other breeds of cattle. To determine whether this unique fat deposition is attributable to the somatotropic axis, we compared pulsatile growth hormone (GH) secretion, plasma levels of insulin-like growth factor-1 (IGF-1) and cellular density of somatotrophs (GH-expressing cells) in the anterior pituitary glands of Japanese Black and Holstein steers. Blood samples were withdrawn every 15 min for 6 h from 14 Japanese Black and 12 Holstein steers at about 17 months of age, and GH and IGF-1 concentrations were determined. The distribution and proportion of GH-expressing cells were analysed by immunohistochemistry combined with point-count morphometry in pituitaries from six steers from each breed aged about 18 to 21 months. Overall mean and baseline plasma GH concentrations were lower ( P P P P P

Effects of fattening on post-mortem pH of beef muscles

The pH of beef psoas major (PM) and longissimus dorsi (LD) muscles at 1·0 h after slaughter were examined among the following four groups: pithed fattening cattle (FP), non-pithed fattening cattle (FN), pithed calves (CP) and non-pithed calves (CN). Differences were observed only in PM muscles. The levels of pH were in the order of FP<FN<CP<CN, and significant differences were observed between CN and FP(P<0·01), and between CP and FP(P<0·05). By two-way cross-classification analysis of variance, significant differences were observed between fattening cattle and calves (P<0·01) and between pithing and non-pithing (P<0·05). These differences may be explained by the different death struggle which was caused by different weights between calves and fattening cattle and by whether the pithing procedure was used or not. Hence, by 1·0 h after slaughter, nearly ultimate pH values (5·60 ± 0·08) were observed in all PM muscles of the FP group.

Effects of pithing on pH, creatine phosphate and ATP-related compounds of beef Psoas major and Longissimus dorsi muscles.

The effects of pithing at slaughter on meat quality were studied in M. longissimus dorsi (LD muscle) and M. psoas major (PM muscle) from steers. Ten steers, half of them pithed and the others not pithed at slaughter, were used for determining pH values and concentrations of creatine phosphate (CP), adenosine triphosphate (ATP) and its breakdown products in the muscles at 2·0 h post mortem. CP was not detected in any PM muscles from pithed steers and no significant differences were observed between pithed and non-pithed steers on the mean values of pH and any compounds, but significant differences were observed in the variance of pH value, ATP, (inosine monophosphate IMP) and inosine levels in PM muscles and of (adenosine diphosphate ADP) and IMP levels in LD muscles. When two steers with excitable temperament were excluded from the pithed group significant differences of variance between the treatments were observed only in PM muscles. The pithing procedure thus affects the levels of pH and of some of the ATP-related compounds in the PM but not in LD muscles.

Changes in Plasma Composition of Japanese Black Steers During Grazing and Fattening Periods

Abstract Nakamura, Y.-N., Orito, H., Tsuneishi, E., Hirano, K., Kato, N., Shoji, A., Kamiya, M. and Nakanishi, Y. 2008. Changes in plasma composition of Japanese black steers during grazing and fattening periods. J. Appl. Anim. Res., 34: 157–161. The plasma compositions of five Japanese black steers during about 23 months of grazing and fattening period of about 6 months were investigated. Plasma A/G, LDH, Glu, tCho and Ins concentrations increased (P<0.05), whereas TG, UNandNEFA concentrations decreased (P<0.05) during the fattening period. Plasma Na concentration increased (P<0.05) during the fattening period. Plasma Bβ-carotene and tocopherol concentrations decreased (P<0.05) during the fattening period. Changes in plasma chemical composition during grazing and fattening were related to the chemical composition of the feed consumed and lack of exercise during housing.

Estimation of Body Fat Mobilization by Single Intravenous Administrations of Epinephrine in Growing-Finishing Pigs

Plasma free fatty acids (FFA) response to single intravenous administrations of epinephrine was investigated in growing-finishing pigs. Four gilts weighing about 65kg were fitted with a jugular catheter a week before the first epinephrine administration trial. Five doses, 0.1, 0.2, 0.4, 0.8, and 1.6μg/kg body weight (μg/kg BW), of epinephrine were intravenously administered through the catheter. Each pig was administered one dose each day, and dose levels were randomly allocated to each animal. Blood samples were drawn through the catheters at -30, -15, 0, 5, 10, 15, 20, 30, 40, 50, 60, 90, and 120 minutes after the epinephrine administration. Area under curve (AUC) of FFA was significantly increased by the epinephrine administrations (P<0.05). The estimated dose producing half-maximal response (ED50) and maximal responsiveness (Rmax) for the AUC of FFA were 0.311±0.113μg/kg BW and 573±167 (μEq/l)•min, respectively. From these results, it seems that in vivo mobilization of body fat in growing-finishing pigs can be estimated by single intravenous administrations of epinephrine.

Effect of Medium Chain Triglyceride Feeding on Blood Metabolite Levels and Fiber Digestion in Steers

中鎖脂肪酸トリグリセリド(MCT)の飼料的利用の可能性を検討するため,育成子牛にMCTを給与して血液成分および飼料消化への影響を調べた.トリカプリリンおよびトリカプリン(C8およびC10のトリグリセリド)が混合(約6:4)しているMCTを用いた.濃厚飼料としてTDNが約70%のC飼料,これを基本にしてMCTを10%添加したM飼料,長鎖脂肪酸トリグリセリド(LCT)を10%添加したL飼料を準備し,ホルスタイン種の去勢子牛6頭(7ヵ月齢)を用いて1期3週間のラテン方格で実験した(C, MCT, LCT区とする).各期の第3週の朝給餌の直前と4時間後に採血し,消化試験も行なった.採食前の血漿酢酸,3-ヒドロキシ酪酸(3-HB)濃度(以下,濃度を省略)には区間で差がなかった.採食後には酢酸,3-HBとも上昇し,とくにMCT区では3-HBおよびアセト酢酸(AcAc)が有意に高かった.採食前のグルコースと乳酸には区間で差がなかったが,採食後にはMCT区で低かった,コレステロール(Cho)とHDL-ChoはLCT区のみ高かった.採食後の非エステル脂肪酸(NEFA)およびトリグリセリド(TG)はLCT区で高かったが,採食前には区間で明らかな差を認めず,インスリンにも差をみなかった.NDFとADFの消化率はMCT区で低かったが,CPの消化率には油脂給与による差がなかった.

Effects of Castration on the Fatty Acid Composition of Various Tissues in the Japanese Shorthorn

牛枝肉の脂質性状に対する去勢の影響と雄牛肥育における粗飼料多給の影響を検討した.実験1では,日本短角種牛を用い,3ヵ月齢去勢(C3),8ヵ月齢去勢(C8),および無去勢すなわち雄(B1)の各区4頭ずつ配置して比較を行なった.実験2では,濃厚飼料多給(BC)と粗飼料多給(BR)の各区2頭ずつ配置して,雄牛肥育における飼養方法の違いによる影響を検討した.なお濃厚飼料給与の去勢肥育牛5頭を対照区(CC)として比較に用いた.(1) 供試した筋肉および脂肪組織から抽出した総脂質における,トリアシルグリセロール画分の脂肪酸組成に関して,雄牛では去勢牛と比べて,C18:0の割合が高く,C16:0の割合が低い傾向を示した.不飽和脂肪酸の割合には区間差がみられなかった.また同じ雄牛の肥育においては,濃厚飼料多給区の方が粗飼料多給区と比べて不飽和脂肪酸割合がやや高い傾向を示した.(2) 筋肉におけるリン脂質画分の脂肪酸組成に関しては,去勢の影響が認められなかった.これに対し飼養条件の違いによる影響は認あられ,BC区はBR区と比べて,ω3系列の脂肪酸の割合が低く,ω6系列の脂肪酸の割合が高い傾向を示した.(3) アルデヒドについては,雄牛は去勢牛と比べて,C18:0の割合が高く,C16:0の割合の値が低い傾向となった.