Optimal dietary taurine level for growth of juvenile Japanese flounder Paralichthys olivaceus

The requirement for taurine in juvenile Japanese flounder Paralichthys olivaceus was determined by feeding diets containing various levels of taurine and cystine. Test diets supplemented with 0.5, 1.0 and 1.5% of taurine or with 0.5, 1.0 and 1.5% of L -cystine were prepared. The basal diet contained 55% protein from white fish meal. These diets were fed to juvenile Japanese flounder with an initial mean bodyweight of 0.9 g (total length (TL) 48 mm) for 5 weeks. Approximately 1.4% taurine content in the diet was required for optimum growth of juvenile flounder. A positive linear relationship was noted between the content of taurine accumulated in the muscle, liver and brain and the level of taurine in the diet. However, there was no increased taurine content in tissues of fish fed the cystine-supplemented diet. In contrast, the fish fed control and cystine-supplemented diets showed higher contents of cystathionine in the tissues. The concentration of cystathionine in tissues rapidly decreased with an increase of taurine in the diet. It was also observed that for each of the dietary groups, a trace amount of taurine was excreted. These results suggest that the taurine content in the diet affects the sulfur amino acid metabolism of juvenile Japanese flounder, and indicate that juvenile flounder are unable to biosynthesize taurine from cystine.     

Effect of taurine supplemented practical diet on growth performance and taurine contents in whole body and tissues of juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

ABSTRACT:   The effect of dietary taurine on juvenile Japanese flounder was determined by feeding three taurine-supplemented experimental diets (TAU) and a commercial diet (CD) to evaluate a practical diet for juvenile Japanese flounder. Juvenile Japanese flounder were reared on the three experimental diets supplemented with taurine at 0, 0.5, 1.0% and CD. These diets were fed to juvenile Japanese flounder of an initial mean body weight of 0.2 g for 6 weeks at 20°C and the taurine contents of the whole body and tissues were analyzed. The final average body weight of juvenile Japanese flounder fed the 1.0% TAU was significantly higher than that of the other groups. Taurine contents in the whole body and tissues increased with the increase in dietary taurine level. These results indicate that juvenile Japanese flounder require at least 15 mg/g taurine in the diet, even though a combined mix of fish, krill and squid meal was the main protein source in the experimental diets.     

Influences of feeding frequency of extruded pellet and moist pellet on growth and body composition of juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> in suboptimal water temperatures

This study was carried out to investigate the influences of feeding frequency of extruded pellet and moist pellet on growth and body composition of juvenile flounder (initial mean weight 6.3 g) in sub optimal water temperatures. A 2 (diets: extruded pellet and moist pellet)×2 (feeding frequencies: two and three times daily)×2 (water temperatures: 12 and 17°C) factorial design with three replications was used. After 60 days of feeding, the feeding frequency did not significantly affect growth performance of fish. Weight gain, daily feed intake, feed efficiency and protein efficiency ratio were significantly (P<0.05) higher for fish reared at the higher water temperature. At the same water temperature, weight gain, feed efficiency, and protein efficiency ratio were significantly (P<0.05) higher for fish fed the extruded pellet than moist pellet. The results of this study indicate that feeding frequency of two times daily is sufficient for optimal growth of juvenile flounder when reared in suboptimal water temperatures, and an increase in water temperature from 12 to 17°C improved growth and feed efficiency.     

铅污染对山皂角生长生理的影响

[目的]研究山皂角在铅污染环境中的生长发育、生理生态的反应及适应性,为治理铅污染土壤提供一定的理论依据及技术指导。[方法]以山皂角（Gleditsia japonica Miq.）为研究对象,通过野外盆栽试验,分别添加纯铅浓度为200、400、800、1 200、1 600 mg/kg（土）,研究不同浓度铅处理对山皂角苗木生长发育、生理方面的影响。[结果]盆栽山皂角根系长度、苗高、地径、质量受到了不同程度的抑制;低浓度的铅处理能够刺激叶绿素含量的形成,高浓度则抑制叶绿素形成;山皂角叶片的脯氨酸含量随铅浓度的升高而增加;铅对硝酸还原酶活性有较强的抑制作用,山皂角过氧化物酶活性随着铅浓度的增加表现出先升高后降低的趋势。[结论]土壤铅浓度在800 mg/kg（土）之内,铅对山皂角的生理影响较小,山皂角可以比较正常生长。     

经济林木柏木在黔东南山区栽培技术要点探析

柏,中性,喜温暖多雨气候及钙质土,耐干旱瘠薄,稍耐水湿,浅根性。具有枝叶浓密,树姿优美的形态特征。喜光,对土壤适应性广,因为黔东南山区地区独特,所以要格外地注重栽培技术。     

Seasonal Changes in the Nutrient Concentrations of Leaves and Leaf Litter in a Young Cryptomeria japonica Stand

The leaves and leaf litter of Cryptomeria japonica D. Don was collected from April 1994 to March 1995 to describe the seasonal changes in nutrient concentrations in leaves and leaf litter. Nitrogen (N), phosphorus (P) and potassium (K) concentrations were in the order new leaves > old leaves > leaf litter, whereas calcium (Ca) concentration was in the order leaf litter > old leaves > new leaves during the whole year. N, P and K concentrations were at their highest during the new leaf growth phase, and then decreased as a result of the diluting effect and translocation, whereas Ca increased with time. Magnesium did not show any clear seasonal trend compared with other nutrients. N resorption efficiency was lower than P resorption efficiency. There were two nutrient resorption peaks, which could be attributed to high nutrient translocation to new leaves in the spring and to translocation from old leaves before senescence in the autumn. A significant correlation between N and P resorption was observed.     

近代日本的两次立宪及特征

日本自近代以来产生了两部宪法,《明治宪法》确立的天皇制把日本最终变成了世界大战的策源地。战后在特殊的历史条件下,日本制定了新宪法《日本国宪法》,重新选择了治理国家的模式,并实现了经济上的巨大成功。     

Histochemical properties of skeletal muscles in Japanese cattle and their meat production ability

The compositional characteristics of the three basic types of myofiber, namely type I (slow‐twitch oxidative), type IIA (fast‐twitch oxidative glycolytic) and type IIB (fast‐twitch glycolytic), are clarified in the skeletal muscles of Japanese Black cattle. The myofiber composition, which is characteristic of the muscles of Japanese Black cattle, markedly changes during their growth, when some type IIA myofibers are transformed into type I or IIB, depending on the different muscles. Independent of these changes with growth, inter‐ and intramuscular variations of myofiber type distribution is evident. The small extensor muscles in deep regions around bone contain a lot of type I myofibers, whereas the large muscles at surface regions have many type II myofibers. Japanese Black cattle have typical white muscles such as the Longissimus thoracis and Semitendinosus, containing half the myofibers as red (type I + IIA). The muscles of Japanese Black cattle show a tendency to contain a higher percentage of type I myofibers than other breeds over an intrabreed variation of the myofiber type composition. In the big muscles such as the Longissimus thoracis and Biceps femoris, a great diversity of myofiber type composition is observed among the different regions. When fattened, heifers produce Longissimus thoracis and Biceps femoris muscles of smaller weight than steers, but in heifers the myofiber size in each type is rather larger. In the Psoas major, Vastus lateralis and Serratus ventralis muscles, heifers contain a higher frequency of red (type I + IIA) myofibers with no differences in myofiber size. Among the several muscles of fattened Japanese Black steers, the percentage distribution of type I myofibers has a positive correlation with the percentage amount of intramuscular fat. From these results, the high potential of Japanese Black cattle to produce marbled beef could be based on the histochemical properties of myofibers in their skeletal muscles.     

Immunolocalization of sex steroid receptors in the epididymis and ductus deferens of immature and mature Japanese Quail, Coturnix Japonica

The goal of this study was to determine whether in the Japanese quail the male genital tract contains receptors for progesterone, androgen and estrogen (PR, AR and ER, respectively), which have significant roles in reproductive functions, and whether their localization changes during sexual maturation. The epididymis and ductus deferens (middle and ampulla regions) of immature (approximately 30-day-old) and mature male Japanese quail were collected and frozen sections of them were immunostained for PR, AR and ER. The immunoreaction products for AR and PR were found in the nuclei of epithelial cells in the efferent ductules, epididymal duct, and the middle and ampulla regions of the ductus deferens of mature and immature birds. In the mature birds, the epithelial cells of the efferent ductules, epididymal duct, and the middle and ampulla regions of the ductus deferens were positive for ER, although some of the cells in the ductus deferens were negative. The epithelial cells of the ductules in the epididymis stained positive for ER, but the immunoreactions were negligible in the ductus deferens of immature birds. These results suggest that the epididymis and ductus deferens in quail possesses PR, AR and ER receptors. Each receptor is expressed before sexual maturation, although enhancement of ER expression may occur during maturation.