热应激对母猪繁殖性能的影响与对策

对福建南安某猪场自2004年1月份至2005年5月份生产母猪各月份的配种率、死胎数、产活仔数等进行统计分析,结果表明热应激对这些指标存在明显的影响,其中以8月份母猪的繁殖力受到的影响最严重,就减少母猪热应激的技术措施进行探讨。     

夏季母猪热应激及应对措施

正在西南地区,夏季气温高、湿度大,高温闷热的天气对猪场的负面影响甚多。热应激是指在高温度环境中机体对热环境做的非特异性的生理反应的总和。母猪夏季热应激一直是困扰现代养猪生产的一大技术难题~([1])。如果猪场饲养管理不当,热应激负面作用更加明显。在各类猪群中,母猪和公猪对热应激最为敏感。母猪受到热应激,采食量会减少,免疫力下降,受胎率下降,母猪产程延长,降低活仔数;增加流产比率,产弱仔、死胎数增加,     

母猪热应激的综合防治措施

热应激时在高温下畜禽末梢感受器在应激原的刺激下,传递到中枢系统,产生的一系列复杂的防卫反应,并对母猪带来一定损害,严重甚至可以导致死亡,对养殖户带来重大经济损失。阐述了母猪热应激的发病机理,带来的危害,临床症状以及综合防治措施。     

一起猪呼吸道综合征的诊治

1发病情况 2006年4月份到7月份期间。福建省福清某猪场母猪存栏120头．全场存栏1300多头，在此期间共有35头母猪发病．其中3头母猪发生流产。32头母猪产死胎，死胎数大部份在怀孕100d以后．死胎数占产仔数1／3左右。母猪的发病率占总母猪数29．1％。在此期间共死亡哺乳仔猪250余头。保育猪发病率在50％左右，死亡率在30％左右。猪场以前没有免疫过猪兰耳病疫苗。猪瘟疫苗、猪伪狂犬疫苗、猪口蹄疫苗有正常免疫。通过笔者采取综合性措施很快控制疫情。     

一起猪呼吸道综合征的诊治

1发病情况2006年月4月份到7月份期间,福建省福清某猪场母猪存栏120头,全场存栏1300多头,在此期间共有35头母猪发病,其中3头母猪发生流产,32头母猪产死胎,死胎数大部份在怀孕100d以后,死胎数占产仔数1/3左右,母猪的发病率占总母猪数29.1%。在此期间共死亡哺乳仔猪250余头。保育猪发病率在50%左右,死亡率在30%左右。猪场以前没有免疫过猪兰耳病疫苗,猪瘟疫苗、猪伪狂犬疫苗、猪口蹄疫苗有正常免疫。通过笔者采取综合性措施很快控制疫情。2临床症状2.1母猪母猪发病时体温在40￣41.2℃,精神不振,采食量下降,外观母猪皮肤较以前苍白,个别表现黄疸…     

胎次、配种次数及断奶日龄对母猪繁殖性能的影响

作者搜集整理了新疆天康畜牧生物技术股份有限公司米泉种猪选育基地2005年—2006年完整的母猪发情配种记录和产仔记录。对母猪不同胎次、配种次数对断奶日龄与窝产总仔数、窝产活仔数、出生重及断奶重的影响进行了分析。结果表明,不同胎次对母猪的繁殖性能影响较大,第一胎繁殖成绩较低,以后逐渐提高;母猪初次配种对其产仔数方面有较大影响,经产母猪繁殖性能稳定。而在排除繁殖障碍等疾病的前提下,泌乳期长的母猪该胎次仔猪断奶重显然高于泌乳期短的;平均断奶重随断奶日龄的增加显著提高(P<0.01)。在仔猪成活方面,断奶期长的仔猪成活数也明显高于断奶期短的仔猪。     

高温高湿对母猪繁殖性能的影响及建议

母猪在温度达到26℃时就受到热应激的影响,夏季高温天气使母猪的繁殖性能有不同程度的下降。如果再加上高湿,母猪受到的影响将更大。在养猪生产的实际中,高温高湿的夏季常常会出现母猪采食量下降、奶水减少、子宫炎、乳房炎、无乳综合征上升、返情明显增加,同时还存在死胎率上升、产仔数减少、仔猪腹泻率高、存活率下降等一系列问题。这是目前生产上普遍存在的一个难题。高温高湿气候不但降低了母猪的利用率,而且     

夏季鸡热应激综合防治措施

鸡由于体温高，代谢旺盛．皮肤没有汗腺，羽毛丰厚，高温下通过呼吸道蒸发散热释放体内产生的多余热量维持热平衡，因此高温时鸡的影响很大。每年6—9月份的高温高湿季节，对鸡来讲是一种环境应激，高温已成为鸡生产中最为严重的应激危害因素。高温应激严重破坏鸡内环境稳定．导致机体热衰竭、营养代谢障碍、酸碱平衡紊乱、免疫功能低下、组织细胞损伤、死淘率增高以及种鸡受精率、孵化率、健雏率降低，给鸡场尤其是饲养设备简陋、饲养管理水平差的养鸡户造成巨大经济损失。因此在天气炎热的夏季应当注意预防鸡的热应激反应。     

影响母猪产仔数的因素

母猪产仔数特别是产活仔数、健仔数是养猪生产水平高低的重要指标之一，直接影响养猪场的经济效益。因此，必须了解影响母猪产仔数的因素，并针对性地采取有效措施，才能达到预期的目的。影响母猪产仔数的因素很多，其中受遗传因素的影响较小，而受温度、配种方式、胎次、母猪配种前后的营养状况及公猪的精液品质等因素的影响较大，现分述如下。 1 猪舍温度 　　生产上后备母猪的适宜生长温度为17～20℃，妊娠母猪的适宜温度为11～15℃。如果猪舍温度过高，对母猪的繁殖将产生极为不利的影响，尤其是配种后15d影响最大。因为高温不利于母猪体热的散发，从而导致猪体内子宫温度升高，不利于受精卵的发育和胚胎附植，胚胎死亡率高，产仔数少。     

猪热应激及其营养调控技术的研究进展

随着全球气候变暖、养猪业集约化程度的提高，使得热应激对养猪生产的影响日趋严重，热应激不仅导致猪生产力的下降，也导致了肉品质的下降，给养猪业带来巨大经济损失。     

Influence of temperature and salinity on survival of the freshwater mullet, Rhinomugil corsula (Hamilton)

The upper incipient lethal temperatures of the freshwater mullet, Rhinomugil corsula, acclimated to 15, 20, 25, 30 and 35°C in fresh water, were 32.4, 34.1, 36.0, 36.2 and 36.5°C respectively, and the corresponding lower lethal temperatures were 10.5, 11.5, 13.2, 15.8 and 19.5°C. The mullet has a total tolerance (area of thermal polygon) of 569°C with an upper and lower thermal tolerance of 253 and 316°C². Likewise, the total resistance of the mullet was 391°C², with upper and lower resistance zones of 181 and 210°C respectively. The upper critical temperatures of swimming inhibition of R. corsula (17.2 cm; acclimation 30°C), determined in a swimming tunnel, were 35.2, 34.6 and 34.2 for water current velocities of 38, 62 and 77 cm s^?1 respectively. The corresponding lower critical temperatures were 26.2, 27.5 and 28.1°C. These results indicated the stenothermal nature of the mullet by comparison with other fishes, e.g. Tilapia mossambica.In tests on the influence of ambient salinity on thermal resistance, R. corsula survived longest at 7‰ (iso-osmotic salinity). At salinities above and below this point, survival times were shorter at any lethal temperature. In a tentative scheme for quantification of stress due to temperature and salinity at death (after acclimation to 30°C and tested at 37°C), the hypo-osmotic and hyper-osmotic stress were estimated to be 50 and 31% of the thermal stress (100%) respectively.     

Thermal resistance traits of the clonal silver crucian carp Carassius langsdorfii and evaluation of these traits using primary culture cells

The thermal resistance traits of three clonal lines of the silver crucian carp Carassius langsdorfii (SCC-1, -2 and -3) were investigated. Individual juvenile fish reared at 20°C were exposed to thermal stress at 36.5 ± 0.5°C and their death times during this exposure were measured. The death times of SCC-2 and SCC-3 fish were 66.6 ± 31.2 and 144.7 ± 49.8 min, respectively. In contrast, all SCC-1 fish survived under these conditions. Furthermore, the thermal sensitivity of primary culture cells from each clone was determined at 37, 40 or 43°C by the Trypan blue assay. Under all treatment conditions, the thermal sensitivity of the SCC-1 primary cultures was lower than those of the others. These results estimated the correlation between the in vivo and in vitro thermal resistances. Therefore, the use of primary culture cells to evaluate thermal resistance could be a useful method of selection breeding.     

Peroxiredoxin 6 from cuttlefish ( Sepiella maindroni ): molecular characterisation during development and the response to thermal stress

The aim of this work was to investigate the function of the peroxiredoxin family member Peroxiredoxin 6 in Sepiella maindroni (Smprx6) during embryonic development and the response to thermal stress. The 1064 bp full-length coding sequence of Smprx6 includes an open reading frame of 660 bp encoding a polypeptide of 219 amino acids with a predicted molecular mass of 24.4 kDa. The deduced protein sequence shares significant homology with other reported Prx6 enzymes. Phylogenetic analysis classified SmPrx6 into the 1-Cys-Prx cluster, and quantitative real-time PCR (qPCR) demonstrated constitutive mRNA expression in all tested tissues and during five different embryonic developmental stages, as previously documented in other cephalopods. Thermal stress induced Smprx6 expression, which peaked at 6 h then returned to control levels. Recombinant SmPrx6 was active at different concentrations and was thiol-dependant. The results suggest that SmPrx6 plays a major role in the development of Sepiella maindroni and its response to oxidative and thermal stress.     

热应激对鱼类hsp70基因和caspase-3基因影响的研究进展

鱼类对温度的适应因其种类不同而有差异,这是长期进化和演变的结果.本文通过对不同种鱼类的最大临界温度和高起始致死温度这两个热耐受性指标、耐热相关基因的表达等进行了综述,发现影响鱼类耐热能力的重要因素是基础水温和温度升高的速率,以及生物的生理及遗传,进而掌握不同鱼类的耐热能力,并对在高温胁迫下表达差异显著的hsp70基因和...     

Effect of thermal stress on Hsp70 gene expression and female reproductive performance of giant freshwater prawn,Macrobrachium rosenbergii

Using Hsp70 as a biomarker, thermal stress impinges on reproductive organs, ovary and hepatopancreas were being analyzed by determining the expression of Hsp70 mRNA inside the organs after the adult inter‐molt females were subjected to thermal treatment at 35, 30 and 28°C (Control). Results showed the expression of Hsp70 mRNA under thermal treatment of 35°C after 2 hr recovery in ovary were upregulated at 2, 4, 6, 12, 24 hr and 30 days compared to control whereas in hepatopancreas under similar treatment, the expression of Hsp70 mRNA were significantly higher than control at 6, 24 hr and 30 days. Frequency of reproductive molt at 35°C showed the ovary of females were failed to develop and only entered common molt along three consecutive molt cycles. For 30°C thermal treatment, the expression of Hsp70 mRNA was significantly higher than control after 2 hr recovery but returned to normal afterwards until 30 days’ thermal treatment. Maternal heat shock for 2 hr at 35°C were found to give significantly lower frequency of reproductive molt and longer duration of ovarian development and incubation period whereas maternal heat shock for 2 hr at 30°C gave lower frequency of reproductive molt, slower development of embryo and lower hatching success compared to untreated control. This study suggests that short and long‐term thermal stress at 30 and 35°C were found to affect the induction of Hsp70 mRNA in reproductive organs of Macrobrachium rosenbergii and also influence their reproductive performance.     

Main stem movement of Atlantic salmon parr in response to high river temperature

Atlantic salmon become thermally stressed when water temperatures exceed 23 °C. To alleviate this stress, they behaviourally thermoregulate by moving to patches of cold water, often forming large aggregations. These patches are known as thermal refuges. Given the consensus that climate change will increase temperatures in Atlantic salmon catchments, thermal refuges will become increasingly important in minimising summer mortalities. While the behaviour of salmonids within thermal refuges is fairly well understood, less is known about their main stem movement in search of thermal refuges or its thermal and temporal cues. We detail the results of a PIT telemetry study to investigate the main stem movement behaviour of thermally stressed Atlantic salmon parr in a temperature‐impacted river. PIT antennas placed around two thermal refuges and at the upstream and downstream limits of their surrounding reach were used to record the movement of salmonids during a heatwave. We observed parr movement at the upstream and downstream antennas 135 min prior to the occurrence of the midpoint of aggregations in the thermal refuges, indicating that Atlantic salmon parr make reach‐scale movements in search of cool water prior to aggregating. Logistic regression showed that the number of degree hours >28 °C predicted the occurrence of main stem movement with a good degree of accuracy, indicating that this temperature represents a fundamental threshold causing Atlantic salmon parr to move towards cool water. Such data could be instrumental in allowing river managers to place limits on human activity within rivers, allowing salmon populations time to recover following heat stress events.     

Determination of optimal temperature(s) in juvenile red‐spotted grouper Epinephelus akaara (Temminck & Schlegel) based on growth performance and stress responses

This study sought to determine the optimal temperature(s) for aquaculture of juvenile red‐spotted grouper Epinephelus akaara (Temminck & Schlegel) (mean initial BW: 3.1 g). Growth performance, insulin‐like growth factor 1 (IGF‐1) expression and thermal stress responses (plasma cortisol, glucose, and hepatic heat shock protein 60 expression) were evaluated at three constant temperatures (24°C, 26°C and 28°C) in a 2‐week trial. At the end of the trial, final BW was significantly higher at 26°C and 28°C than at 24°C (p < 0.05); a quadratic regression analysis of final BW showed the optimum temperature for growth was 27.5°C (p < 0.05, R² = 0.806). The highest hepatic IGF‐1 expression was observed at 26°C (p < 0.05). On the other hand, hepatic heat shock protein 60 expression was highest at 28°C (p < 0.05), suggesting thermal stress. In conclusion, temperature optima, which support excellent growth but induce minimal thermal stress, was 26°C. This fine information within a narrow temperature range is expected to give empirical information for red‐spotted grouper farmers to sustain maximal production efficiency with avoiding thermal stress and to determine the future location of production, especially in consideration of arising seawater temperatures.     

Effects of thermal stress on skin defence lysins of European eel, Anguilla anguilla L.

Fish skin contains a variety of humoral defence lysins which have an integral role in fish immunity because of the ability of these proteins to destroy invading substances ( Alexander & Ingram 1992 ). These lysins generally comprise bacteriolysins, proteolysins and haemolysins. The lysins seem to be either individually or cooperatively stimulated to respond to pathogenic infection and environmental stress, such as ionic, osmotic, thermal and pollution stress ( Shephard 1994 ; Rice, Kergosien & Adams 1996 ; Bly, Quiniou & Clem 1997 ). There have only been a few reports on these lysins ( Al-Hassan, Thomson, Ali & Criddle 1987 ; Aranishi, Mano, Nakane & Hirose 1998 ). The present paper describes thermal effects on defence lysis, such as proteolysis, bacteriolysis and haemolysis, in the skin of the European eel, Anguilla anguilla L.     

大菱鲆胚胎和仔稚鱼的热刺激耐受能力

以培育大菱鲆Scophthalmus maximus耐高温品系为目的,研究了胚胎和仔稚鱼对热刺激的耐受力差别,为通过高温刺激选育大菱鲆耐高温品系提供指导和基础数据。实验分别对大菱鲆胚胎期(孵化前期)、卵黄囊期(初孵仔鱼,0dph)、前弯曲期(10dph)和弯曲期(25dph)的仔鱼、稚鱼(50dph)使用22～33℃范围内不同梯度的高温海水,进行突变热刺激,2h后转入原水体中培育,记录之后60～84h的死亡率、仔鱼孵化率、畸形率等数据。结果表明,上述5个发育期大菱鲆经受2h热刺激的亚致死温度为24、23、<22、28、28℃,半致死温度为26、28、22、29、29℃,致死温度为30、29、27、30、30℃。根据热刺激后24和48h死亡率,耐热能力由弱到强依次为10dph<胚胎<0dph<25dph<50dph,总体上呈现随生长发育逐渐增强的趋势。10dph左右可能为大菱鲆热刺激耐受力低谷,此时也是开鳔期,对外界环境反应灵敏,受到不良环境刺激易导致死亡。