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1.
不同贝龄栉孔扇贝数量性状的相关性和通径分析   总被引：5，自引：2，他引：3  
为深入了解栉孔扇贝形态性状与湿重之间的关系,为栉孔扇贝选育工作中亲贝的挑选提供策略,本研究使用来自同一家系的栉孔扇贝子代324只一龄个体以及生长到二龄的230只个体的性状数据进行通径分析。性状数据包括壳长(x_1/cm),壳高(x_2/cm),壳宽(x_3/cm),湿重(y/g)。结果显示,所有形态性状和湿重之间的相关系数均达到极显著水平。其中与一龄贝湿重相关系数最大的是壳长,为0.939,与二龄贝湿重相关系数最大的是壳高,为0.808。通径分析结果显示,壳长对一龄贝湿重的直接影响最大(0.532),壳高对一龄贝湿重的直接影响最小(0.163)。壳高对二龄贝湿重的直接影响最大(0.451),壳长对二龄贝湿重的直接影响最小(0.191),决定系数与以上通径分析结果的变化趋势一致。利用多元回归的方法构建了一龄贝和二龄贝形态性状与湿重间的回归方程,一龄贝:y=–10.527+0.287x_1+0.087x_2+0.409x_3,R~2=0.926;二龄贝:y=–68.609+0.254x_1+0.719x_2+2.008x_3,R~2=0.830。本研究结果为栉孔扇贝种贝的挑选提供了理论依据。  相似文献   

2.
To determine whether genetic improvement can be attained through a selective breeding programme, divergent selection for shell length was applied to two stocks of Haliotis diversicolor. Stock A was descended from the cross between males from a Japanese wild population and females from a Taiwan aquacultured population and Stock B was from the Taiwan cultured population, which had been successively cultured in mainland China for about 10 generations. The 10% largest and 10% smallest abalones for each of these two stocks were selected as parents for the large‐selected and small‐selected lines respectively. Equal numbers of abalone were randomly chosen from the two stocks to serve as parents for the control lines before the selection. The selected and control lines were reared under the same conditions at early juvenile, later juvenile and grow‐out stages. Stock A showed a significantly higher response to selection and realized heritability than Stock B (P<0.01). The large‐selected line of Stock A and Stock B grew 12.79% and 4.58% faster than their control lines on shell length respectively. The average realized heritability for shell length was 0.441±0.064 for Stock A and 0.113±0.013 for Stock B. Responses to selection were different at different ages in each stock and the body weights of the selected lines were significantly different from the control lines in both stocks at the grow‐out stage. Asymmetric responses to selection in the two directions were also observed in both stocks. Differences in response to selection and realized heritability between the two stocks are presumably due to genetic variability.  相似文献   

3.
ABSTRACT

Two generations of selection for increased body weight in Kansas (AU-KS-2) and Marion (AU-MS-2) lines of channel catfish, Ictaluruspunctatus, resulted in a 12% and 11% increase in body weight at market size, respectively. The second generation of selection produced no improvement in growth, and there was a slight negative response to selection for body weights during the second generation. Cumulative realized h2 was 0.17 ±0.03 and 0.15 ±0.03 for AU-KS-2 and AU-MS-2, respectively, based on growth performance measured against a randomly bred, Kansas control for the two generations. Relative size differences were established by the time the fish reached 80 g, and these relative size differences were maintained the remainder of the experiment. Growth rate of the channel catfish ♀ × blue catfish 6, I. furcatus, hybrid was 35% faster than the Kansas control, and better than all three groups of channel catfish. The growth improvement through interspecific hybridization was three times better than through mass selection.  相似文献   

4.
Red abalone Haliotis rufescens is one of the most valuable mollusks in the international market, but it has a low growth rate. A breeding program is being developed to increase its growth rate in Chile. We estimated the changes in direct heritability (h2), maternal/common environments heritability (m2) and genetic correlations (rG) of growth traits (shell length and width, total mass, flesh mass and foot protein as an indicator of meat quality) measured during 2 years (every 4 months) from the juvenile stage (27 months) to the adult harvesting age (51 months), in 60 full‐sib red abalone families. Heritabilities for growth traits measured in juveniles and young adults (27–35 months of age), were low (0.07–0.17) and not significant. Initial low h2 were associated with significant amounts of maternal/common environmental effects (m2 = 0.4). In young adults and abalone near the harvest age (39–51 months of age) h2 were much higher (0.32–0.75). These results emphasize the importance of multiple estimations of h2 over time. Among meat quality traits, only the h2 for the flesh mass for adults at harvesting age was significant (0.15). We observed strong positive rG (>0.9) between shell sizes (easy to measure) and total and flesh masses (trait more related to market value than shell sizes but harder to measure) for adults at harvesting age. Thus, if the 5% largest 51 month old abalone were selected from the population as broodstock we expect a positively correlated response on flesh mass of 23.4%.  相似文献   

5.
Unidirectional mass truncation selection for small‐sized cysts was carried out on brine shrimp (Artemia franciscana Kellogg 1906), Vinh Chau strain, Vietnam, through cyst sieving and then culturing the selected individuals (<5% of the population) under field and laboratory conditions over two successive generations (F1 and F2). The results showed that at both culture scales, the cyst size of the selected line was smaller (P < 0.05) compared with the control (non‐selected) line, illustrating that there was a response to selection. The cyst size decreased about 3% per generation and the accumulated gain on the target trait was in the range 5.82–6.07% at the end of the selection process compared with the base population. The realized heritability estimation (h2) for cyst size was 0.23 ± 0.06 and 0.74 ± 0.19 in the field trials and 0.34 and 0.51 in the laboratory test for the F1 and F2 generation respectively. The variations found between the respective trials may be explained as the result of environmental interaction with the selection process, but the results show that a selection program for small‐sized cysts in Artemia by mass selection is possible.  相似文献   

6.
Shell thickness in mollusks is generally considered adaptive because of their effects on fitness. However, little is known about the genetic basis of shell thickness. This is important, because the response to selection and the subsequent adaptive microevolution of a trait, such as thickness is only possible when that trait exhibits additive genetic variation. Here, we estimated the narrow‐sense heritability (h2: ratio between additive genetic variance and phenotypic variance) for the traits ‘shell thickness’ and ‘shell length growth’ in a 34‐month‐old cohort of the mussel Mytilus chilensis obtained by using a half‐full sib design and grown in the field. Also, phenotypic and genetic correlations were estimated between both traits. We found that h2 showed significant values for shell thickness (0.294 ± 0.194) and length (0.731 ± 0.379). The phenotypic correlation between both traits was positive and significant; however, the genetic correlation between these traits was not. These results suggest both traits can evolve adaptively by selection, but because these traits did not show genetic correlation, it is possible that selection pressure affecting one trait may not affect the other.  相似文献   

7.
熊本牡蛎多嵴和无嵴品系F3生长性状的连续选择效应   总被引：1，自引：1，他引：0  
为进一步检测熊本牡蛎(Crassostrea sikamea)多嵴和无嵴品系F3的连续选择反应,以2个品系F2上选组为材料,开展2个品系F3混合上选研究,评估2个品系F3生长性状的选择反应、现实遗传力及遗传改进量,解析选育过程中选择效应、品系效应及二者交互作用对生产性状的影响。结果表明:多嵴品系F3生长性状具有较高的现实遗传力,表现出较好的遗传改良效果;无嵴品系F3表现出中等现实遗传力水平,但仍具有一定程度的遗传改良潜能。养成期360日龄时,多嵴品系子代壳高、鲜重的选择反应分别为0.70、0.76;现实遗传力分别为0.40、0.43;遗传改进量分别为7.02%、12.29%;无嵴品系的选择反应分别为0.36、0.33;现实遗传力分别为0.20、0.19;遗传改进量分别为3.74%、5.72%。经过双因子分析模型检测发现:品系来源是影响F3生长性状的主要因子,选择效应是次要因子,二者间不存在明显的交互作用。由此可见,随着连续选择的进行,选择反应逐渐降低,品系来源作用增强,本研究为熊本牡蛎遗传改良和新品系培育奠定了基础。  相似文献   

8.
刘述锡  崔金元  林勇 《水产学报》2013,37(11):1513-1520
为了研究虾夷扇贝浮筏养殖自然稀疏效应和科学养殖密度,2009年8月—2010年7月,对不同密度梯度的3个贝龄虾夷扇贝进行浮筏养殖现场实验。在自然稀疏条件下,逐月调查浮筏养殖不同贝龄的虾夷扇贝壳长生长、湿重增长和累计死亡率,并估算了适宜的扇贝浮筏养殖密度。结果表明,在不同养殖密度条件下,3 个贝龄扇贝周年壳长生长都没有显著差异;1龄贝壳长增长最快,年均增长29.53 mm;2龄贝壳长年均增长23.50 mm;3龄贝壳长增长较慢,年均增长15.47 mm;3个贝 龄扇贝周年湿重增长都没有显著差异,3龄贝和2龄贝湿重增长较快,3龄贝的年均增长约54.07 g,2龄贝的年均增长约37.80 g,1龄贝的年均增长约14.69 g;2 龄贝、3龄贝各养殖密度梯度之间累计死亡率都没有显著差异,3龄贝死亡率介于76.30%～83.33%,2龄贝死亡率介于88.89%～91.78%,养殖密度为150个/层的1龄贝与80个/层和50个/层的1龄贝累计死亡率差异显著。依据自然稀疏模型,浮筏养殖适宜密度3龄贝为4～5个/层;2龄贝为8～16个/层,1龄贝为29～124个/层。  相似文献   

9.
为了检测缢蛏新品种"申浙1号"不同月龄数量性状间的相关性。随机选取4、9、11月龄缢蛏个体60个以上,测量其壳长(SL)、壳高(SH)、壳宽(SW)、活体质量(W),采用相关与通径分析方法分析壳形态性状对活体质量的作用效果。结果显示,各数量性状之间的相关关系均达到极显著水平,其中与4、11月龄质量相关系数最大的是壳长,分别为0.911、0.631,与9月龄活体质量相关系数最大的是壳高,为0.653。通径分析结果显示,对4、9、11月龄活体质量的直接影响最大的分别是壳长(0.562)、壳宽(0.433)、壳高(0.394),决定系数与以上通径分析结果的变化趋势一致。利用逐步回归的方法分别建立4、9、11月龄缢蛏活体质量(W)的最优回归方程:W4=–0.756+0.039SL+0.112SW,R2=0.849;W9=–10.622+0.095SL+0.404SH+0.644SW,R2=0.631;W11=–23.772+0.207SL+0.805SH+0.587SW,R2=0.909。研究结果为缢蛏人工选育过程中的亲贝选择和产量预测等提供了基础数据。  相似文献   

10.
Abilities of detection and preference of food by a Japanese whelk, Buccinum isaotakii, were investigated under laboratory conditions. Consumption per food item and the corresponding assimilation efficiency were also de termined. Whelks were more sensitive to fresh foods than boiled foods, detecting them in a short period of time varying between 3.8 (±0.8) and 23.1 (±3.1) minutes. B. isaotakii preferred fish, polychate and bivalves and the time spent on these foods was more than 10 min as compared with those of shrimp (2.0 min) and squid (1.0 min). The highest daily consumption rate was observed on sardine, followed by scallop, polychaete and oyster. The relationship between shell length and consumption of different food items was positive. The coefficients of determination were relatively high for sardine, scallop, polychaete and oyster (r 2, between 0.46 and 0.51) but not for clam, mussel shrimp and squid (r 2, between 0.003 and 0.176), suggesting that the former could be predators of consumption for B. isaotakii. Observed were relatively high assimilation efficiencies on sardine, scallop, polychaete, and oyster, ranging from 30 to 70%. The present results are the intial information pertaining to the feeding biology of this whelk, thus, in-depth studies like an energy budget are recommended to deepen the understanding about seed production and resource management.  相似文献   

11.
The effect of purified macronutrients on specific dynamic action (SDA) was assessed in juvenile southern catfish (39.81 ± 1.35 g) at 27.5 °C by stuffing iso‐energetic (5 kJ) casein, corn oil, corn starch in sections of grass carp intestine (0.25 g). A control (without filler) and mixed diets were also made (each macronutrient provide one‐third energy). The postprandial metabolic response, i.e. the oxygen consumption curve, was markedly different among fish fed different food. The peak postprandial metabolic rate of fish fed mixed diet (76.7 mgO2 h−1) was significantly higher than that of protein group (66.1 mgO2 h−1), while the latter was significantly higher than those of other groups (56.1 mgO2 h−1 for lipid, 54.0 mgO2 h−1 for carbohydrate and 56.1 mgO2 h−1 for control) (P < 0.05). The SDA durations were 32, 32, 30, 14 and 10 h for mixed, casein, corn oil, corn starch and control groups, respectively. The SDA coefficient (energy expended on SDA as per cent of ingested energy) of casein (9.41%) was significantly higher than that of mixed diet (7.43%) (P < 0.05), while the latter was significantly higher than those of corn oil (3.97%) and corn starch (0.84%) (P < 0.05). The results of this study suggested that the method of using casing on investigation of SDA in carnivorous fish was feasible. The SDA response of carnivorous southern catfish fed protein was higher than lipid while latter was higher than carbohydrate (nearly to zero). The result of this study may give interesting information for understanding the physiological mechanism under SDA.  相似文献   

12.
The Japanese scallop Mizuhopecten yessoensis is one of the most important aquaculture mollusca in Japan and China. In the present study, a high‐quality cDNA library of the Japanese scallop was constructed from the kidney tissue. A total of 2919 expressed sequence tags longer than 100 bp were generated from this library. A cluster of 1440 unique sequences, which consisted of 258 contigs and 1182 singletons, was revealed. Based on blast searches, 882 (61.3%) genes had significant (E‐value <1e–5) matches to known sequences in public databases. Among them, >70 genes were involved in stress response, immunity and apoptosis. These results expanded our knowledge of the genetics and physiology of the Japanese scallop, and provided a useful resource for gene discovery for further research of this species.  相似文献   

13.
In order to improve the yield of bay scallop Argopecten irradians by exploiting geographic subspecies heterosis, crosses between and within two subspecies, the northern A. i. irradians (Lamarck) and the southern A. i. concentricus (Say), were created and the offspring were cultured under the same environmental conditions. The two parental populations were collected from Bohai Bay in northern China and Beibu Bay in southern China, which were distinct in particular shell colours. The results indicated that the shell colour of bay scallop was inheritable and could be used as a morphological mark to distinguish hybrid and purebred individuals. At harvest, hybrid offspring always produced a significantly higher yield than purebred offspring. Positive heterosis was achieved for shell length, shell height, shell width, total weight and adductor weight, which was 5.02, 5.22, 3.88, 7.53 and 9.47 respectively. Hybrid gain was 10.86% for shell length, 10.48% for shell height, 9.77% for shell width, 34.90% for total weight and 41.69% for adductor weight, respectively, and all were significantly >5%. The present study reveals that it is effective for improving yield by hybridization between different geographic subspecies in the bay scallop.  相似文献   

14.
To investigate the effects of temperature and salinity on filtration and oxygen consumption rate of Scapharca broughtonii spat with different growth stages. This study was conducted under six different water temperatures and five different salinity conditions. The spat were divided into three groups of different shell sizes and filtration rates were estimated by Neutral red. The results showed that in all of the three groups, the highest filtration rates appeared at 20 °C, and the highest one was 1.89±0.12 L g h?1 in the group with the lowest shell length (11.8±2.1 mm). The filtration rates in every group increased with the rise of salinity in the range from 10 to 40 g L?1, and the highest one is 2.62±0.21 L g h?1 in the lowest shell length group. The trends of oxygen consumption rates were similar to filtration rates. The highest rates were 0.189±0.003 mg g h?1 at 20 °C and 0.308±0.018 mg g h?1 at a salinity of 40 g L?1 in the group with the lowest shell length. And the results showed that the smaller the shell size, the higher the filtration and oxygen consumption rate.  相似文献   

15.
The ivory shell, Babylonia areolata (Link 1807), has been exploited as an important aquaculture organism along the southern China coast. In order to obtain optimal culture conditions for ivory shell juvenile, the central composite rotatable design was used to estimate the combined effects of temperature, salinity and rearing density on accumulated growth rate (AGR) and survival rate (SR). The results showed that the linear effects of temperature and rearing density on both growth and survival were highly significant (P < 0.01), but there was no significant effect on salinity (P > 0.05). The quadratic effects of temperature, salinity and rearing density influenced growth significantly (P < 0.01). The quadratic effects of temperature and salinity on survival of juvenile snail were significant (P < 0.01), the combined effects between the quadratic effect of temperature and the linear effect of rearing density influenced survival significantly (P < 0.01); the interactive effects of temperature, salinity and rearing density played a significant role in survival (P < 0.01). As can be seen from the above experimental results, the effects of temperature and salinity on growth and survival of B. areolata were strengthened with enhanced rearing density in a certain range and vice versa. By optimization using the response surface method, the optimal point was found at a temperature of 26.81°C, a salinity of 28.76 ppt and a rearing density of 527.07 ind m?2. Under these conditions, the optimal AGR and SR were 36.84 mg day?1 and 99.99%, respectively, with a satisfaction function value of 99.71%.  相似文献   

16.
The thermoregulatory behaviour of green abalone Haliotis fulgens and pink abalone H. corrugata was investigated. Haliotis fulgens juveniles ranging in wet weight from 3.0 to 3.3 g and from 28.7 to 30.5 mm shell length and of H. corrugata 2.0 g and 25.7 mm in shell length were exposed to 19°C for 30 days in a flow‐through water system. Temperature preference was determined in a horizontal thermal gradient and was found to be 25.4°C for green abalone and 25.0°C for pink abalone. Displacement velocity was 4.3 cm h−1 for H. fulgens and 12.8 cm h−1 for H. corrugata. The optimum temperature for growth calculated for both abalone species was 24.6 and 24.5°C respectively. The critical thermal maxima (CTMax) of H. fulgens and H. corrugata were determined as a measure of thermal tolerance. Abalones were subjected to increasing water temperatures at a rate of 1°C on 30 min until they detached from the substrate. The CTMax at 50% were 33.6 and 32.0°C for green and pink abalone respectively. The results are discussed in relation to site selection and commercial rearing.  相似文献   

17.
The effect of dietary macronutrient composition on specific dynamic action (SDA) in southern catfish Silurus meridionalis Chen juveniles (39.0±2.8 g) was studied. A control diet (40% protein, 10% lipid and 15% carbohydrate) was the optimal dietary profile for growth in this catfish according to a previous study. Based on this, two diets were formulated by substituting protein and lipid for one another, referred to as LPHL (30% P:15% L) and HPLL (50% P:5% L), and two diets were formulated by substituting protein and carbohydrate for one another, referred to as LPHC (30% P:30% C) and HPLC (50% P:0% C). The results showed that dietary composition affected the peak metabolic rate, duration and SDA coefficient. The peak metabolic rate in the LPHC group (211.5 mgO2 kg?1 h?1) was significantly lower than catfish in the control (265.2 mg O2 kg?1 h?1) and the HPLC (257.7 mg O2 kg?1 h?1) group. The SDA duration in the control group (26.8 h) was significantly shorter than those of the HPLL (38.0 h), LPHC (33.8 h) and HPLC (33.8 h) groups. The SDA coefficient in the LPHL group (11.1%) was significantly lower than those of the control and the other groups (13.2–15.4%). The results suggest that in southern catfish, the SDA response to dietary carbohydrate is similar to that of dietary protein, and that the SDA may not be affected solely by an increase in the amount of protein ingested, but may be influenced by interaction of other dietary components.  相似文献   

18.

采用双性状选择方法在经群体继代大壳高选育的海湾扇贝(Argopecten irradians concentricus Say)南部亚种F3养殖群体中进行闭壳肌定向选育, 以评价闭壳肌的选择效果和现实遗传力, 为海湾扇贝南部亚种育种提供理论依据。结果表明, 在以壳高为第一选择性状、体质量为第二选择性状、壳高选择压力为10%、体质量选择压力为1%情况下, 正、负向选择组、对照组在产卵量、受精率、孵化率、幼虫期壳长增长率、中培期存活率、成体各形态参数等方面的差异不显著(P>0.05); 在稚贝育成率、养成期存活率、成体各质量性状等方面均存在显著差异(P<0.05), 各指标值均呈现正向选择组>对照组>负向选择组; 正、负向选择组中, 体质量与闭壳肌质量均出现较高的现实遗传力, 且正向选择组高于负向选择组; 双性状选择时, 体质量与闭壳肌质量的当代遗传获得明显高于单性状选择结果。壳高和体质量对闭壳肌质量均具有密切的遗传相关, 任何一个性状的选择均可对闭壳肌质量产生显著影响, 双性状同时选择可对闭壳肌质量产生叠加效应, 使闭壳肌质量性状的遗传进展达到最大。

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19.
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20.
Oxygen demand by all animals is driven primarily by their needs for sustaining metabolism. Typically, larger animals require more oxygen and cellular fuel to carry out respiration than smaller animals. This relationship in most cases is not linear and is usually described by a coefficient and exponent (e.g. axb): the exponent b showing the relationship between live‐weight and energy/oxygen demand and is often termed the metabolic body weight (MBW) exponent, while the coefficient (a) tends to be temperature specific and describes the relationship between MBW and maintenance metabolic energy and oxygen demand at that specific temperature. Across all temperatures (range 26.0–32.0°C), the relationship between barramundi (Lates calcarifer) live‐weight (x; g) and relative oxygen consumption as standard metabolic rate (y; mg O2 kg?1 h?1) at 29.4±1.5°C (mean±SD) was described by the exponential curve: y=710.19 x?0.3268, R2=0.6875 (n=222 assessments). Examination of the same data but on a gross oxygen consumption (mg O2 h?1) basis showed a relationship between live‐weight (x; g) and gross oxygen consumption (y; mg O2 h?1) that was described by the exponential curve: y=0.710 x0.6732, R2=0.9033. Evaluation of the combined relationship between fish live‐weight (y; g) and water temperature (x; °C) on gross oxygen consumption rate (z; mg O2 h?1) was described by the equation: z=(?20.7818+1.4017x?0.0227x2) ×y0.673.  相似文献   

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