Effects of Brown Fish Meal Replacement with Fermented Soybean Meal on Growth Performance, Feed Efficiency and Enzyme Activities of Chinese Soft-shelled Turtle, Pelodiscus sinensis

A 120-day feeding experiment was conducted to investigate the effects of partial replacement of brown fish meal (BFM) by fermented soybean meal (FSBM) in diets of Chinese soft-shelled turtle (Pelodiscus sinensis). The turtles (initial mean body weight, (115.52 ± 1.05) g) were fed with three experimental diets, in which 0%, 4.72% and 9.44% BFM protein was replaced by 0%, 3% and 6% FSBM, respectively. Results showed that the feeding rate (FR), specific growth rate (SGR) and feed efficiency ratio (FER) of turtles fed with the diet containing 3% FSBM were not significantly different from the control group (0% FSBM) (P > 0.05). However, FR, SGR and FER of turtles fed with the diet containing 6% FSBM were significantly lower than those of the control group (P < 0.05). No significant differences were observed in the activities of serum glutamic-oxalacetic transaminase and glutamicpyruvic transaminase among dietary treatments (P > 0.05). However, the uric acid concentration in turtles fed with the diet containing 3% or 6% FSBM was significantly lower than that in the control group (P < 0.05). There were no significant differences in the activities of lysozyme, alkaline phosphatase and total superoxide dismutase among dietary treatments (P > 0.05). The results suggested that FSBM could replace 4.72% BFM protein in turtle diets without exerting adverse effects on turtle growth, feed utilization and measured immune parameters.

Effects of Dietary Vitamins A,B_2,and B_6 Supplementation on Growth and Feed Utilization of Juvenile Chinese Soft-shelled Turtle Pelodiscus sinensis according to an Orthogonal Array Experiment

An orthogonal experimental design OA9 （33） was used to evaluate the effects of vitamins （A, B2, and B6） on the growth and digestive ability of the juvenile Chinese soft-shelled turtle, Pelodiscus sinensis （initial weight, 5.9-0.2 g）. A total of 135 turtles were divided into 9 groups, which each included 15 individuals. The results revealed that vitamin A （VA） had the strongest impacts on the growth rate and feed utilization among the three vitamins; 35,000 IU kg^-1 VA had optimal effects on the feeding intake and specific growth rate, and 20,000 IU kg^-1 VA had optimal effects on protein digestibility and the feed conversion ratio. Vitamin B2 （VB2） was essential for regulating protein deposition and the energy efficiency for growth of the turtles; 120 mg kg^-1 VB2 resulted in increased protein and energy deposition, and 180 mg kg^-1 VB2 had greater beneficial effects on the growth rate. Vitamin B6 （VB6） had important effects on protein and feed efficiency; however, VB6 at an excessive level （120 mg kg^-1） restricted turtle growth. Based on the above growth results, dietary supplementation ofVA, VB2 and VB6 at levels of 35,000 IU kg^-1, 180 mg kg^-1 and 70 mg kg^-1, respectively, were recommended for the juvenile soft-shelled turtle.

Effects of ration level and feeding frequency on digestibility in juvenile soft-shelled turtle, Pelodiscus sinensis

The effects of ration level and feeding frequency on digestibility in juvenile soft-shelled turtle, Pelodiscus sinensis, were investigated. Four ration levels 1.5%, 2.5%, 4.0% and satiation （6.0% BW/d） were used. Apparent digestibility （AD） of dry matter （DMAD）, protein （PAD） and protein real digestibility （PRD） were significantly affected by ration level, but not by feeding frequency when the ration level was similar. However, the feeding frequency affected the AD, DMAD, PAD and PRD significantly when the turtles were fed to satiation. The relationship between fecal protein content （Y） and protein intake （At） can be expressed as a quadric equation： Y=-0.1742＋0.1476X-0.0003X^2 （r^2=0.876, n=27, F=93.92, P〈0.01）.

Effects of Feeding Time on the Growth Performance and Variation of RNA/DNA Ratio of the Chinese Soft-shelled Turtle, Pelodiscus sinensis

The present study was to investigate the effects of feeding time on growth of the Chinese soft-shelled turtle. The experiment was carried out with a photoperiod of 12L （light）： 12D （dark） with lights on at 06：00 and off at 18：00. Turtles were maintained at a temperature of 32 - 0.2 ℃ in tanks throughout the length of the experiment. The turtles in group 1 to group 6 were fed respectively at 00：00, 04：00, 08：00, 12：00, 16：00 and 20：00 with 60 turtles each （Initial body weight 88.27 - 0.09 g）. Acrophases of postprandial RNA/DNA ratio in liver in each group was shown between 5h and 7h after feeding. A positive linear correlation could be seen between specific growth rate （SGR） and RNA/ DNA：SGR=t.1586RNA/DNA-0.7097 （r = 0.9328, P = 0.0066）. The results indicated that the values at the acrophases of about 6h after feeding might be used as an instantaneous growth index in the Chinese soft-shelled turtle. The turtles in group 1 grew better than group 3, group 4, group 5, group 6, because they ate more, but they ate more and grew slower than group 2, whose feed conversion rate was also higher. Meanwhile, the SGR and feeding rate of turtles fed at 12：00 were the lowest from the six groups （P 〈 0.05）. Turtles fed in group 1, group 2 and group 6 developed more heavy final body weight （FBW）, higher feeding rate and SGR than the other three groups. This probably suggested that turtles fed in scotophase grew better than that fed at photophase in total.

Molecular Cloning and Characteristics of Catalase cDNA from Chinese Soft-shelled Turtle(Pelodiscus sinensis)

A catalase cDNA was cloned from the liver of the Chinese soft-shelled turtle （Pelodiscus sinensis） using reverse transcription-polymerase chain reaction （RT-PCR） with degenerate primers. Both 3＇-and 5＇-untranslated regions were isolated by the rapid amplification of cDNA ends method （RACE）. Analysis of nucleotide sequence revealed that the catalase cDNA clone consisted of 2173 bp with an open reading frame of 1587 bp encoding a protein of 528 amino acids. The calculated molecular mass of the mature protein is 59.8 kDa with an estimated pI of 6.84. The peroxisomal targeting signal SNL at the C-terminal and two putative N-glycosylation sites NLSV and NVSQ were found in the catalase. Sequence comparison showed that this catalase, deduced by the amino acid sequence, had high similarity and identity with those of vertebrates recorded in GenBank. Four functional domains and conserved amino acids responsible for binding heme and NAPDH including four essential residues were observed. The 3-D homology model of the turtle catalase was predicted by SwissModel based on the relative domains of bovine catalase structure （PDB ID： 3rgp）. The mRNA expression and enzyme activities in liver, brain, spleen, kidney, heart, gut, lung and muscle were investigated, and the results showed that the mRNA and enzyme activities of catalase in these tissues were species-specific.

Effects of Stocking Density on Water Quality,Growth and Economic Benefits of Chinese Softshelled Turtle Pelodiscus sinensis in Ponds

The Chinese soft-shelled turtle Pelodiscus sinensis is a high-valued freshwater species cultured in China.This study investigated the effects of stocking density on water quality,growth performance and economic return of Pelodiscus sinensis cultured in ponds.P.sinensis were stocked at densities of 1 ind./m^2(LD:low stocking density) and 2 ind./m^2(HD:high stocking density) in 3 000-m^2 ponds,with three replicate ponds for each density.P.sinensis juveniles were fed with a commercial dry pellet feed of 46% crude protein and minced fillet of silver carp ans cultured for 122 days.The results showed that the levels of total nitrogen(TN),total phosphorous(TP),Chlorophyll-a(Chl.a) and turbidity in LD treatment were significantly lower than those in HD treatment(P<0.05).The mean TN and TP concentration in LD treatment was 29.3% and 35.7% lower compared to the HD treatment at the end of the experiment,respectively.Mean survival rates,final weight,average growth rates and PER were significantly higher in LD treatment compared with the HD treatment(P<0.05),respectively.Production was significantly affected by stocking density,which was higher in HD treatment,but the net income was higher in LD treatment.The results suggest that turtles with mean weight 55.6 g rearing at a low stocking density(1 ind./m^2) in ponds had a positive effect on overall economic return and was effective at improving turtle growth performance and water quality.

De-novo characterization of the soft-shelled turtle Pelodiscus sinensis transcriptome using Illumina RNA-Seq technology

The soft-shelled turtle Pelodiscus sinensis is a high-profile turtle species because of its nutritional and medicinal value in Asian countries. However, little is known about the genes that are involved in formation of their nutritional quality traits, especially the molecular mechanisms responsible for unsaturated fatty acid and collagen biosynthesis. In the present study, the transcriptomes from six tissues from Pelodiscus sinensis were sequenced using an IIlumina paired-end sequencing platform. We obtained more than 47 million sequencing reads and 73954 unigenes with an average size of 754 bp by de-novo assembly. In total, 55.19% of the unigenes （40 814） had significant similarity with proteins in the National Center of Biotechnology Information （NCBI） non-redundant protein database and Swiss-Prot database （E-value 〈10-5）. Of these annotated unigenes, 9156 and 11 947 unigenes were assigned to 52 gene ontology categories （GO） and 25 clusters of orthologous groups （COG）, respectively. In total, 26496 （35.83%） unigenes were assigned to 242 pathways using the Kyoto Encyclopedia of Genes and Genomes pathway database （KEGG）. In addition, we found a number of highly expressed genes involved in the regulation of P. sinensis unsatu- rated fatty acid biosynthesis and collagen formation, including desaturases, growth factors, transcription factors, and extracellular matrix components. Our data represent the most comprehensive sequence resource available for the Chinese soft-shelled turtle and could provide a basis for new research on this turtle as well as the molecular genetics and functional genomics of other terrapins. To our knowledge, we report for the first time, the large-scale RNA se- quencing （RNA-Seq） of terrapin animals and would enrich the knowledge of turtles for future research.

Identification of a heat shock cognate protein 70 gene in Chinese soft-shell turtle (Pelodiscus sinensis) and its expression profiles under thermal stress

The heat shock cognate protein 70 (Hsc70) is a member of a 70-kDa heat shock protein (HSP70) family that functions as molecular chaperones.In this study,a novel Hsc70 gene from Chinese soft-shelled turtle (Pelodiscus sinensis) (tHsc70) was identified.The tHsc70 full-length complementary DNA (cDNA) is 2 272 bp long with a 1 941-bp open reading frame (ORF) encoding 646 amino acids.Three characteristic signature regions of the HSP70 family,two major domains of an adenosine triphosphate (ATP)/guanosine triphosphate (GTP) binding domain (ABD),and a substrate-binding domain (SBD) were present in the predicted tHsc70 amino acid sequence.The tHsc70 gene was expressed in Escherichia coli BL21 and the expression product reacted with the anti-Hsc70 mouse monoclonal antibody by Western blotting.Homology analysis revealed that tHsc70 shared identity from 53.9% to 87.7% at the nucleotide level,and 49.1% to 99.5% at the amino acid level with the known Hsc70s.Phylogenetic analysis showed that tHsc70 was clustered together with the Hsc70 gene of another reptile species (Alligator mississippiensis).The tHsc70 was expressed in the liver,lung,heart,and skeletal muscle.The expression patterns of tHsc70 messenger RNA (mRNA) differed among different tissues under different durations of heat stress at 40 °C.Adaptation at 25 °C for 1 h after heat stress was also different among tissues and length of heat stress.Irrespective of different profiles of expression under heat stress,tHsc70 may play roles in protecting turtles from thermal stress.

中华鳖卵黄蛋白原基因克隆与表达及外源E2的影响

为探究中华鳖(Pelodiscus sinensis)卵黄蛋白原Vtg基因的生物学信息与表达及其作为生理与毒理研究标志物的可行性,本实验克隆获得VtgAB1、VtgAB2、VtgAB3(GenBank登录号OK287927、OK287929、OK287928)基因序列,其cDNA长分别为5055、5537、5306 bp,分别编码了1684、1760、1725个氨基酸。三种亚型Vtg蛋白均由脂蛋白N-末端(Vitellogenin_N)、1943DUF、1944DUF、PV、D型血管血友病因子(VWD)5个保守结构域构成,为完整型Vtg。同源性分析发现皆与龟鳖目具有更近的亲缘关系,同时在3种亚型中VtgAB2与VtgAB3更相似。荧光定量PCR显示,3种亚型Vtg只在雌性肝脏中强烈表达。在60日龄、2龄、4龄雌性个体肝脏中,Vtg表达量随年龄呈上升趋势,VtgAB1、VtgAB2为主要表达亚型。原位杂交结果显示,3种亚型Vtg在卵原细胞内未发现杂交信号;在生长期卵母细胞胞质和滤泡细胞中发现杂交信号;成熟期卵母细胞胞质中未发现杂交信号,在滤泡细胞和周围的网状组织中发现杂交信号。信号在初级卵母细胞的细胞质中分布较为均匀且表达最强,随着卵母细胞的发育信号聚集在核周区且信号逐渐减弱。以雄性中华鳖为对象,注射雌激素E2,3种亚型Vtg表达量表现出明显的时间和剂量相关性。研究结果表明,在中华鳖卵黄积累过程中Vtg发挥重要作用,首次证实其Vtg存在内源性合成,并发现其可以作为雌激素暴露的生物标志物。

太湖花鳖和清溪乌鳖形态学、生物学指标和营养组成的比较研究

清溪乌鳖(Qingxi black strain of Pelodiscus sinensis)是基于太湖花鳖(Taihu strain of P.sinensis)体色黑化个体选育而成的新品种,为研究体色黑化对中华鳖群体分化的影响,通过测定太湖花鳖、清溪乌鳖的23项形态学指标、3项生物学指标及营养组成,对太湖花鳖和清溪乌鳖种质性状进行系统评估。结果显示:(1)形态学指标的主成分分析、聚类分析结果一致且两者形态差异主要表现在背甲、腹甲、四肢和头部的形态差异;差异系数分析结果显示两者尚未达到亚种分化水平。(2)太湖花鳖的可食净重占比显著高于清溪乌鳖;而背甲重占比,太湖花鳖显著低于清溪乌鳖。(3)太湖花鳖肌肉中的粗蛋白含量(♂:18.15%,♀:18.08%)显著低于清溪乌鳖(♂:18.85%,♀:18.89%);而粗脂肪含量,太湖花鳖(♂:0.56%,♀:0.56%)显著高于清溪乌鳖(♂:0.43%,♀:0.45%)。(4)清溪乌鳖肌肉中的必需氨基酸/非必需的含量比值(♂:84.44%,♀:85.54%)和呈味氨基酸/总氨基酸的含量比值(♂:38.65%,♀:38.35%)显著高于太湖花鳖(♂:80.59%,♀:81.82%)、(♂:37.88%,♀:37.36%);而必需氨基酸/总氨基酸的含量比值(太湖花鳖♂:50.46%,♀:50.70%;清溪乌鳖♂:51.01%,♀:51.44%),两者之间无显著差异;太湖花鳖裙边中的羟脯氨酸含量(♂:16.08%,♀:16.12%)显著高于清溪乌鳖(♂:15.77%,♀:15.69%)。(5)太湖花鳖和清溪乌鳖肌肉中饱和脂肪酸含量(太湖花鳖♂:31.89%,♀:30.92%;清溪乌鳖♂:31.64%,♀:32.88%)、单不饱和脂肪酸含量(太湖花鳖♂:30.50%,♀:30.160%;清溪乌鳖♂:30.55%,♀:30.71%)、多不饱和脂肪酸含量(太湖花鳖♂:30.94%,♀:30.58%;清溪乌鳖♂:31.98%,♀:32.72%)和EPA+DHA的含量(太湖花鳖♂:12.63%,♀:12.39%;清溪乌鳖♂:12.98%,♀:12.82%)基本接近,仅在个别脂肪酸的含量存在显著差异。

基于ISSR分子标记的中华鳖种群遗传多样性分析

利用简单重复序列间扩增(inter simple sequence repeat, ISSR)分子标记技术对5种中华鳖(Pelodiscus sinensis)种群的遗传多样性以及亲缘关系进行分析。结果显示:采用筛选出的10条ISSR引物对来自5个种群的中华鳖个体样本的基因组DNA进行PCR扩增,共获得123条清晰的扩增位点,平均多态性条带(PPB)比例为73.417%。5个居群的等位基因数(Na)、有效等位基因数(Ne)、Nei’s基因多样性指数(H)、Shannon多样性指数(I)分别为1.748 0、1.417 7、0.245 5、0.370 4,其中乌鳖群体的遗传多样性水平高于其他中华鳖,淮河鳖群体的变异程度最小。5个居群总遗传多样性指数(Ht)=0.240 0±0.037 1,居群内遗传多样性指数(Hs)=0.174 7±0.021 6,基因分化系数(Gst)=0.271 9,基因流(Nm)=1.339 0。总遗传变异结果显示:有27.19%的变异发生在居群间,72.81%的变异发生在居群内。杂交鳖与日本品系之间遗传一致度最高(0.937 1),遗传距离最小(0.064 9);中国台湾品系和乌鳖的遗传距离最大(0.127 5)。聚类分析表明,杂交鳖、日本品系和淮河品系聚为一类群,乌鳖与其他品系差异较大,单独为一类群。该研究结果丰富了中华鳖分子标记信息,分析当前中华鳖遗传资源形势,为新品种选育改良、种质资源管理等提供参考资料和理论指导。

一株中华鳖源维氏气单胞菌的分离鉴定及抗性研究

自保定阜平患病中华鳖(Pelodiscus sinensis)体内分离获得一株革兰氏阴性菌,对其形态特征、生理生化特性及16S rDNA序列进行分析,鉴定其为维氏气单胞菌(Aeromonas veroni);对分离菌株进行了29种抗菌药的药敏试验和15株益生菌的拮抗实验,得出此分离菌株对阿米卡星、头孢呋辛钠、左氧氟沙星、诺氟沙星、头孢曲松、头孢哌酮、环丙沙星和头孢他啶等8种药物高度敏感,对青霉素、苯唑西林、庆大霉素、万古霉素、氨苄西林等其它17种药物表现为不同程度的耐药性;解淀粉芽孢杆菌和枯草芽孢杆菌2种益生菌在一定浓度下对其具有拮抗作用。

甲砜霉素对中华鳖血清生化指标、抗氧化酶活性及组织结构的影响

为研究甲砜霉素(thiamphnicol,TAP)对中华鳖(Pelodiscus sinensis)血清生化指标、抗氧化指标及组织细胞结构的影响,设置16.7、50.1和83.5 mg/kg(体质量计)3个剂量组,每天口服灌喂中华鳖1次,连续给药4 d。于最后一次给药后24 h取样测定其血清生化指标、肝脾抗氧化酶活性并观察组织细胞的变化情况。结果显示:(1)与对照组相比,给药组血清中的谷丙转氨酶(ALT)和谷草转氨酶(AST)均有所增加,在83.5 mg/kg剂量组达到最高值,分别为对照组的7倍和3.7倍;碱性磷酸酶(AKP)、白蛋白(ALB)、总蛋白(TP)、钾离子(K)、及血糖(GLU)等血清生化指标在16.7 mg/kg剂量组显著升高,随着用药剂量增加,含量逐渐降低。Cl^(-)浓度随着TAP的使用有所降低,Ca^(2+)的浓度变化不显著。(2)16.7 mg/kg剂量组肝脏和脾脏中的超氧化物歧化酶(SOD)和一氧化氮合酶(NOS)活性增加,具有明显的诱导作用;而50.1和83.5 mg/kg剂量组活性逐渐降低,说明高剂量TAP对SOD和NO活性产生了抑制作用。肝脏中的过氧化氢酶(CAT)活性在50.1 mg/kg剂量组最高,83.5 mg/kg剂量组含量逐渐降低;脾脏中的CAT活性在16.7 mg/kg剂量组最高,50.1和83.5 mg/kg剂量组活性逐渐降低。16.7 mg/kg剂量组肝脏和脾脏中的丙二醛(MDA)含量均有所下降,50.1和83.5 mg/kg剂量组活性逐渐升高,在83.5 mg/kg剂量组最高。(3)从组织病理可以看出,TAP的使用对中华鳖的消化器官、排泄器官、循环器官、免疫器官、生殖器官均可造成严重的损伤,83.5 mg/kg剂量组对各组织结构影响最大。研究表明,在对中华鳖进行病害防治时,应严格按照TAP的科学用药规程,谨防过度用药和延长用药疗程,以免对机体造成损伤。

饲料中添加还原型谷胱甘肽对中华鳖生长性能、血清生化指标及肝脏超氧化物歧化酶基因表达的影响

本实验旨在研究饲料中添加还原型谷胱甘肽(GSH)对中华鳖(Pelodiscus sinensis)生长性能、血清生化指标和肝脏超氧化物歧化酶基因(sod)表达的影响。选用初始体重为(389.18±5.98)g的中华鳖,分别投喂添加0、100、200和400 mg/kg谷胱甘肽的试验饲料,并依次命名为G0(对照)、G100、G200和G400共4组,8周后测定相关指标。结果显示:中华鳖的增重率和饲料效率随着饲料GSH添加量的增加而升高,均在G200组达到最大值(P<0.05),而各组的肝体比无显著性差异。与G0组相比,G200和G400组肌肉粗蛋白含量和G200组粗脂肪含量显著升高。饲料中添加GSH对中华鳖血清总胆固醇、甘油三酯、血糖、总蛋白和谷丙转氨酶活性均无显著影响,但G400组血清谷草转氨酶活性显著高于G0组。此外,GSH可诱导中华鳖肝脏sod基因的表达,其中G200组sod1基因的相对表达量显著高于G0组;sod2基因表达量随着GSH添加量的增加呈不断升高的趋势,在G400组出现最高值,相比G0组上升1.32倍。研究结果初步表明:饲料中添加一定量的GSH可提高中华鳖的生长性能、肌肉粗蛋白和粗脂肪含量及肝脏sod1和sod2基因的表达。

中华鳖暗温室养殖水体理化因子及微生物多样性分析

暗温室是中华鳖(Pelodiscus sinensis)人工养殖的主要方式之一。为阐明中华鳖暗温室养殖过程中高氮水体和低氮水体中微生物多样性及其与环境因子的关系,在河北省鹿泉中华鳖暗温室养殖池挑选了总氮浓度较高的池塘和总氮浓度较低的池塘进行了水体理化因子监测和微生物多样性对比分析。水体理化因子检测结果显示两种水体的温度均在30℃左右,pH值为7左右,符合中华鳖的养殖要求。两种水体的溶解氧为0.25mg/L左右。高氮水体的总氮、氨氮、亚硝态氮、硝态氮的浓度相较于低氮水体均比较高。高氮与低氮水体在各分类水平上的优势菌群均存在差异,低氮水体绿屈扰菌门(Chloroflexi)占据主要优势,而高氮水体中变形菌门(Proteobacteria)占主要优势,属水平层次上低氮水体中的优势菌为束缚杆菌属(Haliscomenobacter)、亚硝化单胞菌属(Nitrosomonas)。高氮水体多核杆菌属(Polynucleobacter)、亮杆菌属(Leucobacter)占据优势地位,两种水体物种丰富度及相似度存在差异。结果表明高氮与低氮水体不仅在总氮和无机氮浓度上差别较大,微生物多样性也存在明显差距,微生物区系不同可能是造成氮浓度差异的原因之一。

饲料中酶解羽毛粉替代鱼粉对中华鳖生长性能的影响

为研究酶解羽毛粉部分替代鱼粉对中华鳖(Pelodiscus Sinensis)稚鳖的生长与饲料利用的影响,在中华鳖饲料中分别以0%(对照组)、2%、4%、6%、8%的酶解羽毛粉替代等量蛋白质的鱼粉,配制成5种试验饲料,每种饲料分别投喂4个养殖缸,每缸10只鳖,正式试验期30 d。研究结果表明:饲料中添加2%~8%的酶解羽毛粉没有显著影响中华鳖的摄食率和饲料系数(P>0.05),且对中华鳖的体比系数也无显著影响(P>0.05)。然而酶解羽毛粉替代鱼粉却显著影响了中华鳖的生长性能,8%组中华鳖的增重率和特定生长率显著低于对照组和6%组(P<0.05),其它各组之间均无显著差异。因此,饲料中添加6%的酶解羽毛粉不会对中华鳖的摄食、生长与饲料利用产生不利影响,中华鳖饲料中酶解羽毛粉的推荐添加量为6%。

Effect of thermal acclimation on thermal preference, resistance and locomotor performance of hatchling soft-shelled turtle

The significant influence of thermal acclimation on physiological and behavioral performance has been documented in many ectothermic animals, but such studies are still limited in turtle species. We acclimated hatchling soft-shelled turtles Pelodiscus sinensis under three thermal conditions （10, 20 and 30~C） for 4 weeks, and then measured selected body temperature （Tsel）, critical thermal minimum （CTMin） and maximum （CTM^x）, and locomotor performance at different body temperatures. Thermal acclimation significantly affected thermal preference and resistance of P sinensis hatchlings. Hatchling turtles accli- mated to 10~C selected relatively lower body temperatures and were less resistant to high temperatures than those acclimated to 20~C and 30~C. The turtles＇ resistance to low temperatures increased with a decreasing acclimation temperature. The thermal re- sistance range （i.e. the difference between CTM^x and CTMin, TRR） was widest in turtles acclimated to 20~C, and narrowest in those acclimated to 10~C. The locomotor performance of turtles was affected by both body temperature and acclimation tem- perature. Hatchling turtles acclimated to relatively higher temperatures swam faster than did those acclimated to lower temperatures. Accordingly, hatchling turtles acclimated to a particular temperature may not enhance the performance at that temperature. Instead, hatchlings acclimated to relatively warm temperatures have a better performance, supporting the ＂hotter is better＂ hypothesis.