Weaning Research Articles

Application of critical cases specialized nursing group on the sequential ventilation of the COPD patients with respiratory fail-ure

Objective To investigate the impact of critical cases specialized nursing group on the sequential ventilation of COPD patients with respiratory failure.Methods The COPD patients with respiratory failure who were implemented with sequential ventilation in our hospital ICU were selected for research with the retrospective study.The patients from January to November of 2011 who were nursed by the critical cases specialized nursing group were divided into the observation group , the other patients from January to November of 2010 who were nursed by the routine care were divided into the control group , and the clinic effect was observed .Results The nurses of the observa-tion group knew much better about the knowledge of sequential ventilation than them of the control group , the differences were statistically significant （ P〈0.01 ） .Re-intubation rate , VAP incidence , duration of the invasive ventilation , total duration of ventilation , and the du-ration in ICU of the patients in the observation group were significantly lower than those of the control group （ P〈0.05 , P〈0.01 ） .Con-clusions The critical cases specialized nursing group could effectively improve implementation and efficacy of the treatment of the COPD pa -tients with respiratory failure treated by the sequential ventilation , avoid the distress and financial burden because of the failure of weaning and re-intubation , improve the life quality , promote the recovery of the patients , elevate the overall standard of care.It is worthy of clinical application. Key words: Critical cases specialized nursing group; COPD; Sequential ventilation; Effect

Predictors of ventilator weaning in children

Early weaning from mechanical ventilation in children will lead to an extubation failure, however, prolonging mechanical ventilation will increase the risk of ventilator associated complication and the economical burden of disease. Nowadays there is no unified and objective ventilator weaning indexes in pediatrics, so it is significant to searching for appropriate and feasible ventilator weaning indexes. This article detailed the current progress on the condition and predictors of ventilator weaning in children, and comparing the predictability and accuracy of ventilator weaning indexes in children, also looking forward to the possibility of higher accuracy or scheme in ventilator weaning that used for clinical purposes. Key words: Mechanical ventilation; Ventilator weaning predictor; Children

Effects of active cycle of breathing techniques on the respiratory function and quality of life in patients undergoing mechanical ventilation

Objective To study the effect of active cycle of breathing techniques （ACBT） on the respiratory function and quality of life in patieats undergoing mechanical ventilation. Methods A total of 65 patients with respiratory failure treated by mechanical ventilation were randomly divided into control group（ n = 30） and ACBT group （n = 35）. The patients in ACBT group were treated by ACBT, and the patients in the control group were treated by conventional nursing care. Patients＇ vital signs, respiratory function and quality of life were compared. The level of physical recovery and quality of life were measured by the scale of the Barthel index and the activities of dally living （ADL）, respectively. Results In the ACBT group, the mean time of mechanical ventilation was （24. 0 ± 8.9） h and the success rate of ventilator weaning was 77. 1%, which were better than those of （75.0 ±6. 7） h and 53.3% in the control group. There were significant differences between the groups （t = 2. 73,6. 92, respectively ;P 〈 0. 05 ）. At the first day after ventilation, there was no significant difference in the score of ADL between the groups （P 〉 0. 05）. But the score of ADL was significantly different at the third day （t =2. 85,P〈0.05）. 30.0% patients in the control group and 57. 1% patients in the ACBT group had a good viability, the difference was significant （ χ^2 = 6. 47, P 〈 0. 05 ）. Conclusions The active cycle of breathing techniques was useful in shortening the time of mechanical ventilation and can improve patients＇ quality of life. Key words: Quality of life; Active cycle of breathing techniques; Mechanical ventilation; Time of ventilator weaning; Respiratory function

Baby led weaning

In Elternzeitschriften oder auf Babyportalen im Internet begegnet Eltern gerade zunehmend das Thema „Baby led weaning“. Diese vom Baby gesteuerte schrittweise Entwöhnung von Milch hin zu fester Nahrung ist <b>mehr als ein neuer Trend im Beikostdschungel</b>. Für Fachpersonal ist es daher wichtig, die Grundlagen zu kennen, um Eltern entsprechend beraten zu können. Schon immer gab es Babys, die sich nicht an ausgeklügelte Breipläne halten und das durchpürierte Essen verweigerten, aber sich gern am Familientisch bedienten …

Application of percutaneous cardiopulmonary support system in critically ill patients

To summarize the experiences of percutaneous cardiopulmonary support system (PCPS) for critically ill patients and examine the risk factors associated with prognosis. The clinical data of 22 patients with acute severe cardiorespiratory failure on PCPS at intensive care unit of Zhejiang Provincial People's Hospital from September 2006 to February 2013 were retrospectively collected and analyzed. According to the prognosis, they were divided into the survival and mortality groups. And their risk factors of prognosis were analyzed. The PCPS support time was 2-334 (75 ± 10) hours, 14 cases (63.6%) were successfully weaned and 12 cases (54.6%) discharged. The inter-group differences of blood lactic acid level before PCPS, heart ejection fraction, sequential organ failure assessment (SOFA) score and number of multiple organ failure (> 3) were statistically significant (P < 0.05). PCPS is an effective approach for severe acute patients with cardiopulmonary failure. And blood lactic acid level before PCPS, heart ejection fraction, SOFA score and number of multiple organ failure (>3) may be the risk factors related with prognosis.

Contributions to Improvement of Piglets’ Maintenance Conditions

The abandonment as it is possible in alimentation of fodder additives basis on antibiotics and the use of other additives’ types, which are not dangerous for animal health and also for human health, represents a permanent preoccupation of animal breeders from European Union. The replacement of breeding promoters, respectively of antibiotics with fodder phyto-additives, which can be obtained from medicinal plants, have the advantage that they do not present any danger for animals, human and environment. Starting from the truth that pork meat production is determined also by the weaned piglets’ number (economic prolification), in this article we proposed to experiment in the conditions of farmstead breeding the use of some medicinal plants in the rest space for piglets during lactation. The experiment was done in autumn-winter season of years 2011 and 2012 inside the biobasis of Suina Breeding Discipline from UASVM Cluj preparing three nests (C) for three parturition boxes for sows, in the following way: C1 – with rubber bedding and supplementary heat source, C2 – with barley straw bedding and supplementary heat source, and C3 – with barley straw bedding mixed with medicinal plants and supplementary heat source. During the experiment in the three boxes were obtained two parturitions for three sows, and their feeding conditions were identical during piglets’ lactation. In this first stage, the obtained results emphasized differences from a nest to another one as concern the capacity of body weight accumulation and implicitly the survivor capacity of piglets until weaning time. The differences registered in experiment give attention on how to use the medicinal plant mixtures in piglets’ nests during sows’ lactation.

Influence of Environment Factors on Piglets' Viability in Population Farmsteads from Cluj County Incidence

It is known the fact that pork meat production is determined by number of parturated piglets (biological prolification) and by number of weaned piglets (economical prolification). Starting from the reality that many pig breeders of Cluj County incidence have approached programs to extend microfarms, the effected investigations put into evidence the fact that few of those ones involved in pig breeding domain know the aspects bound to demands of sows with piglets given to environment conditions. This article proposes to put into evidence certain mal-functionalities, which appear in population farmsteads, especially in piglets’ obtaining, and subsequently in their feeding, maintenance and attendance until weaning. On the other hand, after effected investigations and observations there were elaborated sets of technical recommendations for breeders interested to develop bussinesses in pig breeding domain. The researches were effected during 2011 and 2012 on a number of 30 heads of pigs (19 sows and 11 young female pigs), which were artificially inseminated on Cluj County incidence. The obtained results give references to biological prolification of sows and young female pigs, to their economical prolification, as well to the technical recommendation sets, different from a farmstead to another one. Taken into consideration the study realized during two years we can give a general conclusion that put into evidence the necessity of genetic re-forcefulness of suina biological material bred in population farmsteads.

Diagnostic and therapeutic methods for perioperative children with congenital heart disease with airway stenosis in pediatric intensive care unit

To explore the diagnostic and therapeutic methods for perioperative children with congenital heart disease (CHD) with airway stenosis in pediatric intensive care unit (PICU). Fiberoptic bronchoscopy was used for the diagnosis of 100 CHD cases in PICU who were clinically considered to have possible airway malformation because of complicated difficult-to-control lung infection, atelectasis and failure with the ventilator after surgery from January 2010 to October 2011. Cases who were confirmed to have severe airway stenosis by bronchoscopy and weaning from the ventilator after surgery were treated with balloon expandable stents into the desired position in the bronchoscopy. There were 73 cases (73%) of CHD patients with airway abnormalities, including 31 cases of severe stenosis (31%), moderate stenosis in 29 cases (29%), mild stenosis in 13 cases (13%). Nine of the 10 children in whom the mechanical ventilation was hard to be stopped after surgery because of severe airway stenosis were weaned from mechanical ventilation successfully by fiberoptic bronchoscopy, while one case died from primary disease with severe sepsis after the placement of bronchial stents. CHD children with difficult-to-control lung infection, atelectasis and failure with ventilator after surgery are often complicated with airway abnormalities. The therapeutic bronchoscopy with airway stent can be used for cases with weaning from the ventilator because of severe airway stenosis.

Clinical study on value of the nasal tube post-pyloric feeding in preventing ventilator-associated pneumonia

Objective To investigate the efficacy of nasal tube post-pyloric feeding in preventing ventilator-associated pneumonia.Methods 67 patients were randomly divided into control group (33 cases) and observation group (34 cases),the control group was used conventional gastric tube,and the observation group was given nasal tube post-pyloric feeding,we compared the serum albumin,CRP,WBC,mechanical ventilation,SOFA and the incidence of reflux,the incidence of VAP,the success rate of weaning from the ventilator and mortality.Results The observation group was significantly higher than the control group in the level of serum albumin,P＜0.05,and was significantly lower than the control group in CRP,WBC,mechanical ventilation,SOFA and the incidence of reflux,the incidence of VAP,and had a higher off-line success rate and lower mortality.Conclusion Nasal tube post-pyloric feeding can satisfy the nutritional needs of critically ill patients.It has advantages of simple operation,safe and low cost,which should be applied widely Key words: Nasal tube post-pyloric feeding; Conventional gastric tube; Ventilator-associated pneumonia; Nutrition

Influence of breast milk on secretion of Ghrelin and Peptide YY in rats

Objective To study the effect of breast milk on secretion of Ghrelin and Peptide YY(PYY) during different periods in SD rats. Methods Sprague-Dawley(SD) rats were randomly divided into breast milk-fed group(BG) and formula-artificial fed group(FG) with 20 in each group.After 21 days both of the 2 groups were fed by same forage.Ten of each group were experimentized in day 21 equivalently weaning period, and rest rats were experi-mentized at the 50th day equivalently childhood.Real-time PCR was used to determine the mRNA of PYY, Ghrelin from gastric, colon.Immunohistochemistry was used to determine Ghrelin, PYY protein expression in the gastrointestinal tract tissues. Results There were no difference between body weight and gastrointestinal mucosal development of 2 rat groups in day 21 and day 50(P>0.05), mRNA and protein expression of Ghrelin and PYY in breast milk-fed group were higher than formula-artificial fed group in both day 21 and day 50(all P<0.05). Conclusions The Ghrelin and PYY levels of breast milk-fed rats is higher than formula-artificial fed ones, and this phenomenon continues to their childhood.Breast milk protects offspring from obesity by influencing the secretion of brain-gut peptide and has long-term consequences on the regulation of food intake and energy balance from neonatal period to their later life. Key words: Breast milk; Formula milk; Peptide YY; Ghrelin

Non genetic factors affecting calf growth traits in mashona cattle

The objective of thisstudy was to evaluate the effects of sex of calf, year of birth, age of calfand age of dam on growth traits of indigenous Mashona calves. The growth traitsunder study were weaning weight (W2), yearling weight (W4) and 600day weight(W6). Data from 1834 purebred Mashona calves were employed, which included calfidentity, year, sex, age, sire and dam, as well as age of dam. The data wasanalysed using the General Linear Models (GLM) procedure of the StatisticalAnalysis System. Tukey’s multiple range tests were performed for testingdifferences between least square means. Weaning weight increased as dam ageincreased up to 10 years after which growth tended to decline. Post-weaningcompensatory growth was apparent in calves of young dams. Male calves grewfaster and were heavier at all stages than female calves. Sex of calf and ageof dam significantly affected calf weaning, yearling and 600day weights. Anumber of years showed a significant difference from each other for all thetraits measured. Records of these traits should always be adjusted for sex ofcalf, year effects and age of dam so as to increase the accuracy of estimationof breeding values as well as rate of genetic gain per generation of selection.

Various factors influencing birth weight in animal production

This is a review article that looks at various factors that influence birth weight in animal production. Birth weight is an important indicator of potential growth of an animal and is affected by both genetic and non-genetic factor, and the birth size depends on their interaction. Environmental conditions such as kind and quality of feed and details of management may have an influence on birth weight in livestock production. In order to minimize the adverse effects of factors that influence birth weight, it is perhaps important to understand the implications of different mechanisms, how and why they affect birth weight. Low birth weight than optimum is the main factor that determine the pre weaning losses of young ones and large birth have been associated with difficult birth. Traditional measures to ameliorate birth associated negative effects should also focus on maternal dietary manipulation which may influence optimum birth weight. Nutritional programs designed to improve dam’s body condition during pregnancy will have a positive influence on birth weight of progeny. A good knowledge of genetic parameters is essential to develop accurate selection indices and to optimally design breeding programs and performance recording systems for maximum economic gain or profit from growth traits. Estimates of genetic parameters for birth weight is model dependent and ignoring of maternal genetic effect in the model leads to overestimation of direct heritability for birth weight. Estimates of direct and maternal heritability for birth weight in different species have been reported and vary from low to high. The review article therefore, concludes that the large variability of birth weight in livestock species suggests that many factors or conditions may be responsible for this variation. The reported low heritability estimates for birth weight may be explained by the poor nutritional levels of dams creating a large environmental variation.

Heritability estimates for weight gain in Nellore in Mato Grosso state, using model of infinite dimension

Abstract: We used 138,976 records of information of body weights ranging from 60 to 610 days of age, from 27,327 Nelore cattle of herds in the state of Mato Grosso. The random regression model with the covariance function of fourth order to describe the variability of the effects of additive genetic, animal and maternal permanent environment and maternal genetic effect and maternal, showed heritability estimates from 0.209 to 0.423 at the beginning by the end of the trajectory, respectively. There is enough genetic variability to promote genetic gain satisfactory performance for weight after weaning period the animals. Keywords : beef cattle, genetic parameters, selection.

Effects of environmental enrichment on maternal behavior of rats with early life stress

Objective To investigate the improve effects of environmental enrichment on maternal behavior in the adult female rats thatexperienced early-life stress, and to explore the molecular biological mechanism. Methods The newborn Wistar rats were divided into two groups randomly, the early life stress group and the control group. Pups from the former were separated from their mothers once per day for 4 hours from PND 2-21(day of birth was considered PND=0), and suffered vicious stimulus during the daily 4 hours maternal separation from PND 8-21. On PND 22(weaning), pups from the early life stress group were divided into two groups: 12 female pups were reared singly, refered to as isolated-rearing group; another 12 were placed in a big cage that was filled with all sorts of rodents toys, refered to as enriched-rearing group; control female pups were placed in groups of 4 per cage. Mating with male rats when female pups reached PND66, then being placed in cages singly when they were detected pregnant. Maternal behavior was evaluated on the second and sixth day after delivery, and the hypothalamic OTR mRNA levels were examined by RT-PCR. Results The results of maternal behavior observation showed that the total time of retrieve and the latency of licking were significantly longer in isolated-rearing rats compared with the normal and the enriched-rearing rats(P<0.01); total time of licking in enriched-rearing rats was longer than the normal and the isolated-rearing rats(P<0.01) on the sixth day after delivery; and the score of the nest building was obviously lower in isolated-rearing rats, especially on the sixth day after delivery(P<0.01). Hypothalamic OTR mRNA levels in the isolated-rearing rats showed strongly decreased compared with the normal rats(P<0.01), but which close to normal levels in enriched-rearing rats. Conclusion Early life stress can damage some components of maternal behavior, such as retrieval, licking, nest building, but it has no obvious effect on crouching behavior; it also decreases the hypothalamic OTR mRNA levels of the adult female rats; as a kind of early environmental intervention, groups-rearing could make hypothalamic OTR mRNA levels of the female rats that subjected to early life stress restore to normal, and thus reverse the disruptions of stress in maternal behavior. Key words: Maternal behavior; Early life stress; Oxytocin receptor mRNA; Environmental enrichment

Breastfeeding behavior among infants aged 6-24 months and difference between urban and rural areas in Southwest China

Objective To understand the status and difference of breastfeeding behavior in urban and rural areas of Southwest China.Methods From March to July in 2011,3659 infants aged 6-24 months were selected by stratified cluster randomized sampling method in urban and rural areas of three provinces of Southwest China (Sichuan,Yunnan and Guizhou),including 1801 (49.2％)infants from urban areas and 1858(50.8％) from rural areas.Basic information of these infants,their families and breastfeeding was obtained by a questionnaire for the mothers or baby-carers.Descriptive analysis and survival analysis (Kaplan-Meier method) were used to describe breastfeeding behavior.Chi-square test and Log-Rank test were used to identify the differences of breastfeeding behavior between urban and rural areas.Results Early breastfeeding initiation rate within one hour after birth was 10.7％(355/3315),and the numbers of urban and rural areas were 12.3％(198/1604) and 9.2％ (157/1711),respectively,x2 =8.691,P＜0.05.Totally,20.3％(725/3575) of all infants were initially fed by breast milk after delivery,and 25.1％ (440/1754) in urban areas and 15.7 ％ (285/1821) in rural areas,x2 =49.192,P＜0.05.The exclusive breastfeeding rate and breastfeeding rate within four months after birth were 35.5％ (27.4％ in urban and 43.6％ in rural areas,x2=88.678,P＜0.05)and 76.2％ (68.5％ in urban and 84.3％ in rural areas,x2 =124.702,P＜0.05),respectively.However,the exclusive breastfeeding rate and breastfeeding rate within six months after birth reduced to 11.3％ (7.9％ in urban and 14.4％ in rural areas,x22 =18.001,P＜0.05) and 65.0％ (54.0％ in urban and 76.3％ in rural areas,x2 =199.662,P＜0.05),respectively.The median breastfeeding duration was 8.0 months (7.0 months in urban and 9.0 months in rural areas,x2 =96.780,P＜ 0.05).The most common reason of weaning was insufficient breast milk which accounting for 48.7 ％ of families [56.9％ (1161/2385) in urban and 39.9％(462/1157) in rural areas,x2=68.840,P＜0.05].Conclusions In Southwest China,intervention program should be implemented to improve the breastfeeding status.Breastfeeding behaviors are different between urban and rural areas in Southwest China.The initiation of breastfeeding in urban area is better,but the sustainability of breastfeeding is better in rural area. Key words: Infant; Breast feeding; Maternal behavior; Cross-sectional studies

Study on factors influencing the failure of PiCCO on weaning from mechanical ventilation in ARDS patients

Objective To analyze and evaluate the variability and effects of extra-vascular lung water index (EVLWI),preload and cardiac function on weaning from mechanical ventilation in patients with ARDS.Methods All patients suffered from ARDS were treated with mechanical ventilation and monitored by pulse indicator continuous cardiac output (PiCCO) till they reached weaning criteria,then spontaneous breathing trial,weauing and extubation were performed in succession.The enrolled patients were divided into two groups,namely success group and failure group according to clinic outcome after weaning in 48 hours.EVLWI,preload markers such as global end-diastolic volume index (GEDI),intrathoracic blood volume index (ITBI),and cardiac function such as cardiac output and cardiac index were compared between two groups before weaning (T0),0.5 h after weaning (T1),0.5 h after extubation (T2),and observational endpoints (T3) (Observational eudpoint is defined as “ before re-intubation” in failure group or 48 h after extubation in succcss group).Results A total of 69 ARDS patients were enrolled from August 2010 to September 2012.Compared with variables before weaning,GEDI and ITBI were markedly higher observed at T1 and T2 (P ＜ 0.05).EVLWI was significantly increased at T1,T2 and T3 (P ＜ 0.01).Increased pulmonary vascular permeability index (PVPI) were also found at T3 (P ＜ 0.05).Compared with the success group,GEDI and ITBI in the failure group were higher at T1,T2 and T3 (P ＜0.05),and EVLWI were significant higher at T2 and T3 (P ＜ 0.05),and increased PVPI at 33 (P ＜0.05).Conclusions Additional volume load may result from weaning off mechanical ventilation and extubation in ARDS patients,and can induce high pulmonary vascular permeability causing pulmonary edema and weaning failure.Therefore,monitoring of EVLWI and preload markers could be valuable to predicting the prognosis of weaning from mechanical ventilation. Key words: Acute respiratory distress syndrome ; Mechanical ventilation; Pulse indicator continuous cardiac output ; Extravascular lung water index

EFFECT OF LACTIC ACID ADDITION IN DIET ON GROWTH PERFORMANCE OF PRE WEANING PIGLETS.

Several factors are likely to influence voluntary feed intake in pre weaning and post weaning piglets, including preweaning environment, age at weaning, creep feeding and health status etc. Various nutritional approaches for optimizing the weaning transition and minimizing enteric diseases have been tested in the past decade. Various organic acids are used to increase the feed intake in pre weanling and post weanling piglets. Organic acids normally used as an acidifier in animal feeds have been considered to be alternatives for improving nutrient digestibility and growth performance of weanling pigs (Risley et al., 1992). Hence an experiment was undertaken to study the impact of lactic acid supplementation in creeper diet on growth performance of pre weanling piglets.

Post weaning growth performance of Hyla F1 rabbits under the guinea savannah zone of Nigeria

Data on 144 successfully weaned Hyla rabbit kits consisting of 70 Hyla purebred and 74 crossbred Hyla rabbits were evaluated for postweaning growth performance at different ages (8, 10 and 12 weeks). Breed and sex effect differs significantly (P<0.05) at different ages studied. Crossbred male Hyla rabbits had the highest weight of 1314.57 g and 1771.52 g at 8 and 10 weeks, while the highest value (2232.88 g) at 12 weeks was observed in crossbred female Hyla rabbits. It is therefore concluded that crossbred Hyla rabbit would be suitable meat production in the guinea savannah zone of Nigeria.

POST-ZYGOTIC REPRODUCTIVE ISOLATION IN THE AFRICAN VLEI RAT OTOMYS IRRORATUS (MURIDAE: OTOMYINAE)

ABSTRACT Post-zygotic reproductive isolating mechanisms among three chromosomally distinct, allopatric populations (Committee's Drift, Hogsback, Karkloof) of the vlei rat Otomys irroratus (Brants, 1827) were studied by means of laboratory breeding trials. Data from intrapopulation pairings, all of which produced young, provided a baseline for assessment of the reproductive performance of interpopulation, backcross, and hybrid cross pairings. Although 83.3% of interpopulation cross pairings produced young, overall reproductive success tended to be impaired: progeny of both the Committee's Drift × Hogsback and Committee's Drift × Karkloof pairings experienced increased pre-weaning mortality, while the tertiary (weaning) sex ratio of Committee's Drift × Karkloof hybrids (10: 24) significantly favored females. Backcross and hybrid cross breeding were severely impaired: respectively, 26.4% and 11.1 % of pairs produced litters, and almost all of the Hogsback-cross hybrids that survived to sexual maturity were s...

Developmental changes in the expression of Kiss1 gene and estrogen receptor α gene in hypothalamus of female Sprague-Dawley rats

Objective To investigate the function of Kiss1 gene and estrogen receptor α gene (ERα gene) in puberty of rats, by detecting the expressions of Kiss1 mRNA and ERα mRNA in the hypothalamus and the serum luteinizing hormone(LH) and estradiol(E2) level of female Sprague-Dawley(SD) rats at various stage of development with Real-time PCR and enzyme-linked immunosorbent assay(ELISA). Methods Thirty-five female SD rats of 3 days were weaned on postnatal(PND)22 and then the vaginal opening condition was observed daily.The rats were sacrificed at PND 15(juvenile group, n=19) and PND 35(pubertal group, n=16). The hypothalamus were segregated and the serum were extracted from heart blood.All of the samples were stored at-80 ℃ prepared.Then the mRNA were extracted from the hypothalamus and the cDNA obtained by reverse transcription were tested with real-time PCR.The relative mRNA expression level of Kiss1 gene and ERα gene were calculated. Results 1.Entire level: it was found that the pubertal group vaginal opening time was (32.1±1.0) days, while the juvenile group was not found with vaginal opening until sacrificed.2.Real-time PCR: the expressions of Kiss1 and ERα gene were significantly increased in pubertal group(Kiss1 gene: 5.39±2.52, ERα gene: 1.57±1.87) compared with juvenile group(Kiss1 gene: 1.06±1.09, ERα gene: 0.59±0.68), and the differences were statistically significant(all P<0.001).3.ELISA: the serum LH and E2 in pubertal group[LH(11.61±0.95) IU/L, E2(167.53±31.09) ng/L]were significantly higher than LH[(5.46±1.89) IU/L]and E2[(58.59±29.96) ng/L]in juvenile group, and the differences were statistically significant(all P<0.001). Conclusion Kiss1 gene and ERα gene are involved in the start of the sexual development of female SD rat. Key words: Kiss1 gene; Estrogen receptor α; Hypothalamus; Sexual development; Female Sprague-Dawley rat