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21.
The major carp Catla catla is a popular freshwater edible fish and an extensively cultured species in India. However, basic information on the physiology
of reproduction is lacking in this species. By virtue of its surface feeding habit, it maintains close contact with environmental
light, and is a species of choice for the study of temporal organization of reproduction under natural and experimental conditions
for understanding environmental and/or endocrine mechanisms that control the annual reproductive cycle. The present review
covers information gathered in recent years to emphasize the temporal pattern of reproductive events and the importance of
photoperiod and melatonin, a hormone of the pineal gland that links the environment with the endocrine system in the regulation
of reproduction. Finally, the outcome of the research is discussed in terms of its direct and indirect applications to aquaculture
of this species with a view to manipulate its breeding at a desired time of the year to meet market demand. 相似文献
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23.
Edyta Molik Tomasz Misztal Katarzyna Romanowicz Edward Wierzcho 《Livestock Science》2007,107(2-3):220-226
Changes in day length and the related secretion of melatonin and prolactin are of particular significance in sheep, as they determine reproductive processes, the last stage of which is lactation. The aim of the present study was to examine the dependence of the lactation duration and efficiency on the season of lambing (January—Group I/June—Group II) in relation to the hormonal status of milking ewes (Polish Longwool). The possibility of artificial extension of the milking period in late-lambing ewes by application of prolonged day length, 16 h of light–8 h of darkness (16L:8D), was introduced additionally (Group III). Measurements of plasma levels of prolactin and melatonin were used as parameters of season-dependent hormonal regulation of milk production in this seasonally breeding species. Although during the first 28 days of lactation sheep of all groups produced similar amounts of milk (based on the weight gains of the lambs), our results clearly showed that during the period of machine milking (from weaning at 56 day to the dry period) the level of milk production in Group I was almost twice that noted in Group II. Thus, the highest milk yield was obtained from sheep during the period when the days became longer, i.e. from March to May, which was accompanied by an increase in prolactin secretion. In both groups, melatonin secretion was found to increase while milk performance parameters and prolactin secretion decreased during the shortening photoperiod. The sustained decreases in milk production and prolactin secretion were also observed during the autumn months in sheep from Group III, despite the low level of melatonin. The present study showed that time of lambing and related photoperiod length could significantly affect the milk production of sheep that have a clear season of sexual activity. Maintenance of June-lambing sheep under the 16L:8D regime failed to extend the high prolactin level and lactation considerably into the autumn months. The spontaneous decrease in prolactin secretion observed under the long artificial photoperiod indicated for a development of refractoriness, which could also limit the lactation period. 相似文献
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25.
【目的】明确褪黑素处理对采后常温货架期梨果实贮藏品质的影响。【方法】以新梨7号果实为试材,设置50、100、150、200、250μmol·L-15个褪黑素浓度梯度处理,以清水处理为对照,测定了常温货架期果实失重率、硬度、可溶性固形物含量、乙烯释放速率、香气物质种类和含量等指标。【结果】从处理后5、10、15和20 d的测定结果可以看出,与对照相比,褪黑素处理减少了梨果实内水分的消耗,果实的失重率升高的幅度小,果实硬度较高,150μmol·L-1褪黑素处理失重率和果实硬度与对照差异达显著水平;褪黑素处理能够使新梨7号果实的可溶性固形物含量稳定,处理20 d时,不同浓度褪黑素处理可溶性固形物含量显著高于对照;褪黑素处理新梨7号果实的乙烯释放速率均低于对照,以150μmol·L-1褪黑素处理最低,较对照减少了87.05%,差异显著;不同浓度褪黑素处理对新梨7号果实香气物质种类和含量存在差异,褪黑素处理能调节果实香气种类和含量。【结论】外源褪黑素处理可延缓新梨7号梨果实失水,保持果实硬度和可溶性固形物含量,减少乙烯释放。适宜浓度褪黑素处理可调节香气物质的种类和含量,保证常温货架期贮藏品质,综合认为,150μmol·L-1浓度褪黑素处理能够有效延缓梨果实的衰老,处理效果最好。 相似文献
26.
本研究以‘顶峰Ⅲ’为供试多年生黑麦草（Lolium perenne）品种,研究了低温和干旱胁迫下内源褪黑素（melatonin,MT）的响应,并采用叶面喷施不同浓度MT （0,20,100,1 000 μM）的方法,探讨了MT对低温和干旱胁迫下黑麦草幼苗生长和抗氧化防御系统的影响。结果表明：低温和干旱胁迫下内源MT水平均显著增加（P<0.05）;在不同胁迫强度下,喷施一定浓度的MT会在一定程度上降低叶片相对电导率、使幼苗鲜重发生改变,其中100 μM的MT处理对提高幼苗鲜重和降低相对电导率的效果最佳;低温和干旱胁迫下,黑麦草叶片中O2·-,H2O2和丙二醛（malondialdehyde,MDA）含量显著增加;过氧化物酶（peroxidase,POD）,过氧化氢酶（catalase,CAT）,抗坏血酸过氧化物酶（ascorbate peroxidase,APX）和谷胱甘肽还原酶（glutathione reductase,GR）活性发生不同程度的改变;MT显著地降低了MDA和活性氧的积累,提高了CAT,APX和GR活性及脯氨酸含量。综上,低温和干旱胁迫下MT能够诱导植物体内抗氧化酶活性增强和脯氨酸积累,有效地清除活性氧,从而缓解了黑麦草的生长抑制,增强了其抗寒和抗旱性。 相似文献
27.
Plasma melatonin in domestic female Mediterranean sheep (Comisana breed) and goats (Maltese and Red Syrian) 总被引：2，自引：0，他引：2
The plasma melatonin nychtemeral profiles in Mediterranean ewes and goats were evaluated six times throughout the year. Melatonin levels were high throughout the night and generally below the assay detection limit during daytime. However, during long days, 30% of the last daytime samples had high melatonin concentrations. Plasma melatonin levels were higher in Comisana sheep than in goats, and higher in Maltese than in Red Syrian goats, with highly significant effect of the individual animal and high repeatability. Plasma melatonin was higher in April than in August. When there was a large difference between the duration of day and night, the plasma melatonin pattern and the light/dark cycle did not always match exactly, suggesting some form of superimposition and/or the prevalence of an endogenous rhythm. The difference found at similar scotoperiods with increasing or decreasing day length may be involved in the perception of the photoperiodic changes. 相似文献
28.
褪黑素、谷胱甘肽对猪精液冷冻保存效果的影响 总被引：1，自引：0，他引：1
本试验旨在研究褪黑素、谷胱甘肽两种抗氧化剂对精子冷冻的保护效应。以成年杜洛克公猪为研究对象,在猪精液冷冻稀释液中先后单独、联合添加褪黑素、谷胱甘肽,解冻后精子质量通过检测活率、活力、顶体完整性、线粒体活性以及活性氧（ROS）含量来判定。结果表明：分别单独添加0.25mg/mL褪黑素、5mmol/L谷胱甘肽,或联合添加0.125mg/mL褪黑素和1mmol/L谷胱甘肽,均能减少精液冷冻过程中ROS的生成,显著提高冷冻精子解冻后的质量（P〈0.05）,其中联合添加效果显著优于单独添加效果。 相似文献
29.
AIM: To explore the histocompatibility of pinealocyte microencapsules in vivo. METHODS: The pineal glands of neonatal rats were removed under operating microscope and pinealocytes were isolated through collagenase and trypsin digestion. Pinealocytes were cultured for one week in vitro and collected immediately after digesting was encapsulated in APA microencapsules. The cells and empty capsules were transplanted into abdominal cavity or intermuscular space respectively and retrieved at the 15th or 30th day after operation. Morphological observation, HE staining, cell counting, and HPLC technique were used to analyze the shape, proliferation and function, the degree of inflammation fibrosis of retrieved microencapsules. RESULTS: The retrieve rate of cell capsule from abdominal cavity was about 85%. The retrieved capsules had integrated profile mostly although some were damaged. The amount of macrophages attached to capsule wall and the thickness of wall increased gradually following the period of transplantation. However, the retrieve rate, wall thickness had no difference between retrieved cell and empty capsules at the same time. Secretion ability of pinealocytes in capsule retrieved at 15th day after operation decreased rapidly and those retrieved at 30th day after operation lossed secretion function. CONCLUSION: APA microencapsules had histocompatibility relatively in vivo and protected pinealocytes in capsule from immunologic rejection of the host. The survival time was about 20 days. During this period cells in capsule maintained activity and MT secretion ability. 相似文献
30.
Manabu TANABE Hiroshi TAMURA Toshiaki TAKETANI Maki OKADA Lifa LEE Isao TAMURA Ryo MAEKAWA Hiromi ASADA Yoshiaki YAMAGATA Norihiro SUGINO 《The Journal of reproduction and development》2015,61(1):35-41
Melatonin protects luteinized granulosa cells (GCs) from oxidative stress in the follicle during ovulation. However, it is unclear in which cellular components (e.g., nuclei, mitochondria, or plasma membranes) melatonin works as an antioxidant. GCs from immature (3 wks) ICR mice were incubated with hydrogen peroxide (H2O2; 0.01, 0.1, 1, 10 mM) in the presence or absence of melatonin (100 μg/ml) for 2 h. DNA damage was assessed by fluorescence-based immunocytochemistry using specific antibodies for 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative guanine base damage in DNA, and for histone H2AX phosphorylation (γH2AX), a marker of double-strand breaks of DNA. Mitochondrial function was assessed by the fluorescence intensity of MitoTracker Red probes, which diffuse across the membrane and accumulate in mitochondria with active membrane potentials. Lipid peroxidation of plasma membranes was analyzed by measuring hexanoyl-lysine (HEL), a oxidative stress marker
for lipid peroxidation. Apoptosis of GCs was assessed by nuclear fragmentation using DAPI staining, and apoptotic activities were evaluated by caspase-3/7 activities. H2O2 treatment significantly increased the fluorescence intensities of 8-OHdG and γH2AX, reduced the intensity of MitoTracker Red in the mitochondria, increased HEL concentrations in GCs, and enhanced the number of apoptotic cells and caspase-3/7 activities. All these changes were significantly decreased by melatonin treatment. Melatonin reduced oxidative stress-induced DNA damage, mitochondrial dysfunction, lipid peroxidation, and apoptosis in GCs, suggesting that melatonin protects GCs by reducing oxidative stress of cellular components including nuclei, mitochondria, and plasma membranes. Melatonin helps to maintain the integrity of GCs as an antioxidant in the preovulatory follicle. 相似文献