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1. The effects of the beta-adrenergic agonist, clenbuterol (1 mg/kg diet) on the growth and muscle composition in female broiler chickens (14 to 32 d of age) fed on diets containing various concentrations of protein (220, 240 or 260 g protein/kg) were examined. 2. Body weight gain over the 18 d period increased linearly with increasing protein intake. The rate of gain was significantly higher in clenbuterol-treated chickens than in control birds. 3. Dietary clenbuterol increased thigh muscle weight and protein concentration of breast and thigh muscle, regardless of dietary protein content. Protein/DNA ratio in thigh muscle was enhanced by clenbuterol feeding, and the magnitude of difference of the ratio was higher in chickens fed on the 240 and 260 g CP/kg diets than in those fed the 220 g CP/kg diet. 4. It was concluded that clenbuterol-treated chickens require increased dietary protein to maintain maximal growth, and that increased protein consumption is an important factor in improving growth in clenbuterolfed broilers. 相似文献
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ABSTRACT: The appropriate water velocity in artificial burrows for theJapanese crayfish species Cambaroides japonicus was studied.An experimental system of two artificial burrows (burrows A and B)of the same size was set in a large tank. The velocity of burrowA was 0 cm/s and that of burrow B was varied andset at 0 cm/s, 5 cm/s, 10 cm/s,20 cm/s and 30 cm/s. The selectionof these two burrows by C. japonicus was observed. No animalsselected burrow B significantly more than burrow A above 10 cm/s.At 20 cm/s, some crayfishes were swept away andcould not return to burrows because of the high water velocity.At 30 cm/s, most animals were swept away. We concludethat the appropriate water velocity for the suitability of artificialburrows and the immediate foraging area adjacent to the burrowsshould be as low as 5 cm/s. 相似文献
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Glucose is utilized for oxidation and synthesis of various lipids in cultured rat embryos. The present experiment examined the effect of insulin on the incorporation of glucose into lipid fractions in rat embryos in vitro . Embryos at the 2-cell, 8-cell and blastocyst stages were incubated for 5 h in hamster embryo culture medium (HECM)-1 containing 14 C-glucose and 170 nmol/L insulin, or in HECM-1 containing only 14 C-glucose, and the oxidation of glucose in these embryos was examined. In addition, the total lipids of blastocysts were separated by thin layer chromatography and the radioactivity of the separated lipid fractions was measured. Oxidation of glucose was significantly increased after insulin treatment compared with that without insulin treatment in 8-cell embryos and blastocysts ( P < 0.05), but not in 2-cell embryos. Incorporation of glucose into lipids in blastocysts was significantly lowered by insulin treatment compared with that without insulin treatment ( P < 0.05). Most of the radioactivity was recovered from triacylglycerols of blastocysts and the remaining radioactivity was found in other neutral lipids and phospholipids. We conclude that insulin accelerates the utilization for oxidation of glucose and inhibits the storage of triacylglycerols in rat blastocysts. 相似文献
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SIQIN Mari NAKAI Tomohiro HAGI Shinichi KATO Ali Mohammed PITIA Mai KOTANI Yuki ODANAKA Yasushi SUGAWARA Koh‐Ichi HAMANO Keiichiro YOGO Yoshio NAGURA Masaru FUJITA Hiroshi SASADA Eimei SATO Tetsuya KOHSAKA 《Animal Science Journal》2010,81(6):681-686
Relaxin‐like factor (RLF), also known as insulin‐like factor 3 (INSL3), is produced by testicular Leydig cells, but its specific receptor LGR8 (leucine‐rich repeat family of G‐protein‐coupled receptor 8) has not been identified in goats. This study aimed to identify complementary DNA (cDNA) sequences of goat LGR8, and characterize the expression of both RLF and LGR8 in goat testes by RT‐PCR and immunohistochemistry. Testes were collected from immature (3‐month‐old) and mature (24‐month‐old) Saanen goats, and partial cDNA sequences of the goat homologue of human LGR8 were identified. The sequence encoded a reduced peptide sequence of 167 amino acids, which corresponded to transmembrane regions 2 through 5, followed by the beginning of intracellular loop 3 of human LGR8. Expression of both LGR8 and RLF genes was drastically increased in mature testes compared with immature ones. Although RLF protein was restricted to Leydig cells, LGR8 protein was detected in both Leydig cells and seminiferous epithelial cells (possibly germ cells and Sertoli cells). These results reveal a possible existence of the RLF‐LGR8 ligand‐receptor system within the goat testis, suggesting that RLF may play a role in testicular function through LGR8 on Leydig cells and seminiferous epithelial cells in an autocrine and/or paracrine manner. 相似文献
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双酚A对体外培养家蚕生精囊形成精子的影响 总被引：1，自引：0，他引：1
为了探讨环境有害物质对家蚕生殖发育的影响,利用家蚕生精囊(spermatocyst)体外培养系统,研究塑料工业广泛使用的化合物双酚A(BPA)对体外培养家蚕生精囊精子形成的影响。在5龄第4天家蚕生精囊体外培养体系中添加100μg/mLBPA,可使生精囊全部不能伸长,绝大多数在72 h内死亡;添加10μg/mL BPA时,生精囊培养72 h后表现出明显伸长障碍,有核精子束数量减少且长度短;添加1μg/mL BPA时,有核精子束数量减少且长度短,还出现一些退化膨大的生精囊。在上蔟第2天的家蚕生精囊体外培养体系中添加0.1μg/mL BPA,可对无核精子形成产生毒性效应,明显影响到有核精子束的形成及精子束的浓缩成熟。实验结果显示:较低浓度的BPA对家蚕精子形成具有明显的毒害作用;上蔟第2天的家蚕生精囊体外培养体系对低浓度BPA的毒性反应敏感,可应用于家蚕以及昆虫的生殖毒理体外研究实验。 相似文献
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Masahiro TAKAHASHI Hideki TSUCHIYA Seizo HAMANO Toshio INABA Noritoshi KAWATE Hiromichi TAMADA 《The Journal of reproduction and development》2013,59(6):595-598
This study examined two female offspring of a somatic cell cloned Holstein cow
that had reproduction problems and milk production performance issues. The two
offspring heifers, which showed healthy appearances and normal reproductive
characteristics, calved on two separate occasions. The mean milk yields of the
heifers in the first lactation period were 9,037 kg and 7,228 kg. The relative
mean milk yields of these cows were 111.2% and 88.9%, respectively, when
compared with that of the control group. No particular clinical abnormalities
were revealed in milk yields and milk composition rate [e.g., fat, protein and
solids-not-fat (SNF)], and reproductive characteristics of the offspring of the
somatic cell cloned Holstein cow suggested that the cloned offspring had normal
milk production. 相似文献
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KAZUYOSHI NAKATA a TATSUO HAMANO KEN-ICHI HAYASHI TADASHI KAWAI 《Fisheries Science》2002,68(4):763-767
ABSTRACT: Lethal limits of high temperature were studied to clarify the effects on the survival of the endangered Japanese crayfish species Cambaroides japonicus and the alien species Pacifastacus leniusculus . After the acclimation period for 2 weeks at 16°C, the temperature was raised at a rate of 1°C per week. As a result, the ultimate upper lethal temperatures of C. japonicus and P. leniusculus were 27.0 and 31.1°C, respectively, and the lethal temperature for P. leniusculus was significantly higher than for C. japonicus . The natural distributions of these two species are discussed in terms of the temperature tolerance. 相似文献