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1.
A 95‐day feeding trial was conducted to quantify the methionine + cystine requirement for finishing lambari, Astyanax altiparanae (6.10 ± 0.11 g). Six extruded isoproteic (310.14 g/kg crude protein) and isoenergetic (19.76 MJ/kg gross energy) diets were prepared to contain 6.71, 8.31, 11.31, 13.12, 15.59 and 19.74 g/kg dry diet of methionine + cystine. Quadruplicate groups of female lambari were randomly assigned to 24 aquaria (70 L each) and fed to apparent satiety six times daily. The methionine + cystine requirement was determined by quadratic regression analysis of growth performance, whole body composition, muscle development, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity against dietary methionine + cystine concentrations, at 5% significance. Fish fed 6.71–11.31 g/kg dry diet of methionine + cystine showed increased weight gain, per cent weight gain, specific growth rate and protein efficiency ratio. There were no significant differences in whole body composition, muscle growth and activity of AST and ALT in fish fed the dietary treatments. In conclusion, according to the second‐order polynomial analysis of weight gain, the optimum dietary methionine + cystine requirements for finishing lambari were estimated to be 13.66 g/kg dry diet (4.40% dietary protein).  相似文献   

2.
The objective of this work was to evaluate the association between morphometric variables and carcass characteristics in Pirapitinga. We used a thousand specimens of Pirapitinga with an average weight of 1,200 g, which were stunned, slaughtered, weighed, measured, and processed for morphometric and processing yield analysis, to obtain weights, carcass and fillet yields. Initially, the linearity of the variables was verified. Pearson's simple and partial correlation tests were performed between all metrics. Track analysis was performed considering the weights and yields of carcass and filet as dependent variables and the others as independent variables. Ridge regression models were used to eliminate the effects of multicollinearity among the independent variables. Observations showed that the simple correlations between body weights and yields were superior to the partial ones in terms of magnitude. The length and circumference of the specimens were the measures most linearly associated with weight, carcass weight and fillet with rib weight. As for carcass yield and fillet yield, linear correlation coefficients were low and not significant when associated with body weights. With the path analysis, we could observe significant positive correlations between the morphometric measurements for weight, carcass weight and fillet with rib weight. The standard length, body circumference and body circumference/body height ratio are the most correlated. The latter are the most important variables in the evaluation of body weights in Pirapitinga fish. They can serve as criteria for indirect selection in searching for fish with better carcass characteristics. As for fillet and carcass yields, the morphometric variables have not shown to be efficient for indirect selection.  相似文献   

3.
This study aimed to evaluate the effect of different levels of conjugated linoleic acid (CLA) on growth performance, carcass chemical composition and fatty acid profile of lambari (Astyanax altiparanae). A completely randomized experimental design with six treatments, diets with graded levels of CLA (0.0, 5.0, 10.0, 15.0, 20.0 and 25.0 g kg?1) and five repetitions. Fish (n = 570; weight: 1.58 ± 0.23 g) were distributed into 30 (70‐L) aquaria and fed the experimental diets during 90 days. No effects of dietary supplementation with CLA on fish performance and carcass chemical composition were observed. CLA influenced carcass fatty acid profile, a positive relationship was found for 16:1 n‐9, 18:1 n‐9, 18:2(cis‐9, trans‐11), 18:2(trans‐10, cis‐12) and 20:1 n‐9, and a negative relationship was found for 15:1 n‐7, 16:0, 16:1 n‐5, 18:2 n‐6, 18:3 n‐3, 20:5 n‐3 and 22:4 n‐6. Total CLA and monounsaturated fatty acids (MUFA) linearly increased with the increase in dietary CLA, while saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) of n‐6 and n‐3 series linearly decreased. Dietary CLA can be incorporated into the lambari (A. altiparanae) muscle, and the fish can be used as functional foods, because CLA is related to the prevention of various diseases in humans.  相似文献   

4.
The anaesthetic potential of menthol was evaluated in lambari Astyanax altiparanae by exposing fingerlings to concentrations 50, 100, 150, 200, 250 and 300 mg L?1 and measuring the induction and recovery times to deep anaesthesia, the mortality rates during and 96 h after procedure and after 6 min of continuous exposure. The effect of menthol on stress responses were evaluated by comparing glucose and cortisol levels of juveniles subjected to anaesthesia (50 mg L?1), stress (air exposure) or pre‐anaesthesia associated to stress. All concentrations induced deep anaesthesia within 0.5 to 1 min, with recovery between 1.83 and 4.16 min, without mortality during the induction or up to 96 h after exposure. Induction time decreased and recovery time increased linearly as the menthol concentration increased. Continuous exposure to 50, 100 and 150 mg L?1 concentrations resulted in mortality rates of 0%, 20% and 80% respectively. Anaesthesia or air exposure increase blood glucose but prior anaesthesia with menthol suppressed the elevation of cortisol caused by stress. Menthol has an anaesthetic effect and attenuates the stress response in lambari and 50 mg L?1 is the most effective concentration for inducing deep anaesthesia in 1.0 min, safe for up to 6 min exposure.  相似文献   

5.
Meat yield of 233 individuals of giant freshwater prawn, Macrobrachium rosenbergii (de Man, 1879), and their morphometric relationships were examined. Morphometric parameters of different length and weight measurements were recorded for both the sexes separately and subjected to analysis. The meat yield of prawns was size and sex dependent with females showing significantly greater (P < 0.05) tail meat yield than males. The tail meat as a body weight percentage ranges from 26.12 to 40.75 and 32.97 to 42.11 in males and females, respectively. Much of the differences in yield are related to the size and weight of the head and claws. The head weight of males was observed to be higher compared to females in all the size classes. Regression slopes of total length versus body weight and total length versus head weight were significantly higher than critical isometric value indicating high positive allometric growth in both the sexes, with males showing significantly higher (P < 0.05) slope than females. The relationship parameters of total length versus tail weight and total length versus tail meat showed a positive allometric growth in females, whereas it is isometry and negative allometry in males. The morphometric relationship of tail length versus all weight measurements showed positive allometry and negative allometry in females and males, respectively.  相似文献   

6.
日本沼虾五群体形态性状对体质量的通径分析   总被引：4，自引：0，他引：4  
为筛选出影响日本沼虾体质量的主要形态性状,以便确定人工选育的理想测定指标,以太湖、鄱阳湖、白洋淀、微山湖及淀山湖的野生日本沼虾为研究对象,随机选取各群体90尾虾测定19个形态指标,采用简单相关分析和通径分析等多元回归分析方法分析各群体对体质量作用较为突出的形态性状,并进行聚类分析。通径分析结果显示,太湖群体体长、头胸甲宽、第二步足长、头胸甲高、尾扇长对体质量的通径系数达到极显著,逐步回归建立其对体质量的回归方程、回归截距及相应的回归系数分别为–9.878、0.075、0.314、0.011、0.320、0.222;鄱阳湖群体头胸甲长、尾扇长、尾节宽、头胸甲宽、头胸甲高、尾节高、体长性状对体质量的通径系数达到极显著,回归截距和相应的回归系数分别为–1.618、0.392、–0.280、0.703、0.524、–0.359、0.688、–0.061;白洋淀群体体长、头胸甲宽、第二步足长和尾扇长对体质量的通径系数达到极显著,其回归截距和相应的回归系数分别为–4.796、0.082、0.222、0.007、0.136;微山湖群体头胸甲长、腹节高、第二步足长、腹节宽对体质量的通径系数达到极显著,其回归截距和相应的回归系数分别为–7.644、0.248、0.329、0.025、0.301;淀山湖群体体长、第二步足长、头胸甲宽、尾节宽、腹节宽对体质量的通径系数达到极显著,其回归截距和相应的回归系数为–6.257、0.019、0.018、0.164、0.264、0.162。体长与头胸甲性状在不同群体中都对体质量的作用十分明显。聚类结果显示,地理位置越接近,形态上越相似。研究表明,各个地区被保留的性状与体质量的复相关系数为0.965、0.904、0.902、0.971、0.955,为影响各自群体体质量的主要自变量。  相似文献   

7.
This study aimed to evaluate the potential of oregano oil as a growth promoter for the yellowtail tetra, Astyanax altiparanae. The fish (1.46 ± 0.09 g) were distributed into twenty‐four 60‐L aquaria at a stocking density of 0.5 fish/L. Six isonitrogenous (350 g crude protein/kg) and isocaloric (4272 kcal gross energy/kg) diets containing 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 g/kg of oregano oil were evaluated. At the end of 90 d there was a quadratic effect of oregano oil levels for weight gain, specific growth rate, protein efficiency ratio and carcass weight, and the estimated values to maximize these variables were between 0.2 and 0.6 g/kg. There was also a quadratic effect on the feed conversion ratio, and the estimated value to improve this variable was 0.62 g/kg. A positive linear effect of the treatments was observed for muscle glycogen. With increased levels of oregano oil in the diet, there was a reduction in dry matter and ether extract and an increase in the protein content of the carcass. Thus, it can be concluded that oregano oil, at the level of 0.5 g/kg, acts as a growth promoter for A. altiparanae by improving growth performance and carcass composition.  相似文献   

8.
The effects of clove oil anaesthetic on mitigating the physiological responses to air exposure, a stressful and routine situation in fish farming, laboratory conditions and sport fishing (catch and release), were evaluated in lambari (A. altiparanae). Adult females (n = 80) were randomly sorted to receive one of four treatments: control, anaesthesia (clove oil 50 mg/L), stress (5 min air exposure) and pre‐anaesthesia associated to stress. Their cortisol, glucose, lactate and haematocrit levels, the hepatosomatic index (HSI), liver and muscle glycogen, lipid peroxidation and the enzymatic activity of lactate dehydrogenase (LDH), catalase (CAT) and glutathione reductase (GR), were recorded. Glucose levels increased (53.9%) after anaesthesia and/or stress. The stress situation increased plasma cortisol (146.6%), lactate (294.6%) and lipid peroxidation in white muscle (45%) and decreased glycogen in white muscle (40.1%). The haematocrit increased after stress or anaesthesia (7.9%) while the liver glycogen and HSI did not change. Anaesthesia or stress did not affect the LDH but reduced the activity of CAT (46.1%) and GR (30.3%). We concluded that the anaesthetic clove oil in the concentration 50 mg/L modulates the physiological responses to air exposure stress improving the welfare; air exposure and clove oil affect the antioxidant defences of lambari; the activity of CAT and GR and the concentration of MDA can be used as biomarkers of stress in A. altiparanae.  相似文献   

9.
The ontogeny of the tetra fish Astyanax lacustris, from embryogenesis through the larval and juvenile periods, is presented. The eggs and larvae were obtained through induced reproduction. The larvae were collected at hatching and daily, until all stages of development were obtained and, later, once a week, until the juvenile period. The eggs are small, slightly adhesive and demersal, and have a transparent chorion, yellowish calf and meroblastic cleavage. The larvae hatch 19 hr after fertilization (26ºC). The standard length during initial development ranges from 2.17 to 18.10 mm. The larvae have a subterminal mouth, simple nostrils, a pair of adhesive organs on the back of the head (newborn larvae), spherical eyes and medium‐length intestines. The initial pigmentation is scarce, concentrated in the anteroposterior ends of the yolk sac, but intensifies from the flexion stage, with chromatophores in the mouth and in the cephalic region; the humeral region and the caudal peduncle have a macula at the end of the larval development. The total number of myomeres: 32–38, 15–20 preanal and 14–20 postanal. Juveniles showed similar morphology and pigmentation to adults. The number of fin rays: pectoral 11–12; pelvic 6–7; dorsal 10–11; and anal 27–29.  相似文献   

10.
3月龄卵形鲳鲹形态性状对体质量的影响分析   总被引：3，自引：0，他引：3  
为了探明卵形鲳鲹(Trachinotus ovatus)幼鱼形态性状对体质量的影响程度,分别测定其全长(TL)、体长(SL)、头长(HL)等11个形态学指标和体质量(BW)。分别计算形态性状测量值和体质量数值之间的通径系数和决定系数,分析各形态性状对体质量性状的关联程度。分析结果显示,卵形鲳鲹被测量形态性状对体重的相关系数皆达极显著水平(P0.01);在通径分析中,3月龄卵形鲳鲹仅全长、体宽、体高和尾柄高的形态性状测量值对幼鱼体质量数据的通径系数达到极显著水平(P0.01),可将其确定为影响体质量的主要性状,其中全长对体质量的直接影响最大(P_2=0.493 6);决定系数分析显示,全长对体质量的决定系数最大,达到24.39%。卵形鲳鲹的4个形态性状与体质量性状的相关指数大小为R~2=0.888 1,说明该被选性状是与体质量关联的主要性状。设全长(X_2)、体高(X_3)、体宽(X_4)和尾柄高(X_(10))为自变量,设体质量(Y)为因变量,建立多元回归方程:Y=-32.217 8+0.252 4X_2+0.378 2X_3+0.440 8X_4+0.634 1X_(10),回归预测的估计值与实际值间差异不显著(P0.05),故该方程可被用于卵形鲳鲹的实际生产。本研究可为卵形鲳鲹选育工作提供理论依据和测量指标。  相似文献   

11.
为探讨卵形鲳鲹不同月龄选育群体主要形态性状对体质量的影响,跟踪测量了1月龄,4月龄,7月龄,10月龄和13月龄个体的全长(x1),体长(x2),体高(x3)和体质量(y),共测量2 635尾。运用相关分析、多元回归分析和通径分析的方法,计算了以体质量为因变量,其他形态性状为自变量的相关系数、通径系数和决定系数,剖分各性状对体质量的影响,建立最优多元回归方程。结果显示,在不同生长阶段,4个性状间的相关系数在0.017～0.960之间,除4月龄个体体高与其他性状间相关性不显著外,其他月龄群体各性状两两之间的相关性均达到了极显著水平;1月龄和4月龄个体全长对体质量的直接作用最大,7月龄、10月龄和13月龄个体则是体高对体质量的影响最大;各性状对体质量决定程度分析与通径分析变化趋势一致,各月龄群体全长、体长、体高估算体质量的多元线性回归方程的拟合度良好(86.9%～90.6%)。研究表明,影响体质量的主要形态因素已找出,选育时期不同,所选择的形态性状也应有所差异,为卵形鲳鲹选择育种提供了必要的技术参数。  相似文献   

12.
Relationships among total weight (W), and linear measures of body shape, visceral component weights, and fillet weight (Y) in market-size (>454 g) palmetto bass (Morone saxatilis female ×M. chrysops male, N= 138) and paradise bass (M. saxatilis female ×M. mississippiensis male, N= 134) were determined with the allometric equation: Y = aWb. Allometric analysis was used to compare traits of palmetto bass and paradise bass, and to identify factors influencing fillet yield. Paradise bass, an all female hybrid, had deeper, thicker, shorter bodies, and smaller heads than palmetto bass females. Male and female palmetto bass had similar body shapes. Values of growth coefficients (b) for body shape traits (range 0.21–0.48) indicated that shape was proportional across the weight range of fish used. Mean visceral fat and ovary weight were higher in paradise bass than in palmetto bass females suggesting the reproductive cycle was more advanced in paradise bass females. Whole fillet (skin and ribs intact) and skinless fillet (ribs intact) were larger for paradise bass than for palmetto bass, but trimmed fillet (skin and ribs removed) was not different between fish. Relative increases of whole and skinless fillet weights were greater than total weight in both groups indicating that the percentage of body mass attributed to fillet increases slightly as total weight increases. Therefore, small increases in fillet yield can be achieved by rearing fish to a larger size. Stepwise regression of whole, skinless, and trimmed fillet weight on body shape traits resulted in three parameter models with r2-values of 0.27–0.29 in palmetto bass, and of 0.37–0.43 in paradise bass. Addition of visceral components as independent variables in the models increased r2-values to 0.31–0.36 for palmetto bass and to 0.45–0.52 for paradise bass. Low phenotypic variation in fillet yield (CV = 3–5%) and poor predictability of yield from measures taken on live fish limit the potential for improving yield through individual selection. Identification of superior species or strain crosses or rearing fish to a larger size appear to be the best strategies for improving fillet yield of Morone hybrids.  相似文献   

13.
A single-generation dataset consisting of 1,730 records from a selection program for high growth rate in giant freshwater prawn (GFP, Macrobrachium rosenbergii) was used to derive prediction equations for meat weight and meat yield. Models were based on body traits [body weight, total length and abdominal width (AW)] and carcass measurements (tail weight and exoskeleton-off weight). Lengths and width were adjusted for the systematic effects of selection line, male morphotypes and female reproductive status, and for the covariables of age at slaughter within sex and body weight. Body and meat weights adjusted for the same effects (except body weight) were used to calculate meat yield (expressed as percentage of tail weight/body weight and exoskeleton-off weight/body weight). The edible meat weight and yield in this GFP population ranged from 12 to 15 g and 37 to 45 %, respectively. The simple (Pearson) correlation coefficients between body traits (body weight, total length and AW) and meat weight were moderate to very high and positive (0.75–0.94), but the correlations between body traits and meat yield were negative (?0.47 to ?0.74). There were strong linear positive relationships between measurements of body traits and meat weight, whereas relationships of body traits with meat yield were moderate and negative. Step-wise multiple regression analysis showed that the best model to predict meat weight included all body traits, with a coefficient of determination (R 2) of 0.99 and a correlation between observed and predicted values of meat weight of 0.99. The corresponding figures for meat yield were 0.91 and 0.95, respectively. Body weight or length was the best predictor of meat weight, explaining 91–94 % of observed variance when it was fitted alone in the model. By contrast, tail width explained a lower proportion (69–82 %) of total variance in the single trait models. It is concluded that in practical breeding programs, improvement of meat weight can be easily made through indirect selection for body trait combinations. The improvement of meat yield, albeit being more difficult, is possible by genetic means, with 91 % of the variation in the trait explained by the body and carcass traits examined in this study.  相似文献   

14.
圆斑星鲽(Verasper variegatus)作为中国鲽形目(Pleuronectiformes)养殖鱼类的重要代表种类,具有生长速度快,可食用部分多,肉质细嫩等特点。为了探究圆斑星鲽形态性状与体重的关系,本研究分别测定11月龄、14月龄和17月龄3个不同生长期圆斑星鲽的体重及全长(FL)、体长(BL)、体高(BH)、头长(HL)、头高(HH)、尾柄长(CL)、尾柄高(CH)、吻长(SL)共计8个形态性状,分别进行相关分析和通径分析,剖析形态性状对于体重的直接作用和间接作用;利用回归分析的方法,建立各个时期以形态指标为自变量,体重为因变量的最优线性回归方程。结果显示,1)不同生长阶段,影响体重的重点形态指标存在差异,影响11月龄圆斑星鲽体重的主要形态性状为体高和体长,14月龄阶段为全长、体高和头长,17月龄阶段为全长和体高;2)11月龄、14月龄和17月龄形态性状对体重(Y)的多元回归方程分别为:Y=-186.412+17.381XBH+10.517XBL,Y=-362.484+13.145XFL+20.172XBH+21.199XHL,Y=-816.147+24.121XFL+40.575XBH;3)除本研究所包括的形态指标外,体厚可能为另外一个影响圆斑星鲽体重的重要指标。本研究阐明了体重与形态指标间的相关关系,为圆斑星鲽的良种选育提供了生物学依据。  相似文献   

15.
Abstract. Based on a pooled sample of 367 specimens of juvenile Atlanlic salmon, Salmo salar L., from eight geographically distinct home rivers, stocks from Scotland and Newfoundland can be distinguished by meristic and morphometric character sets using discriminant analysis procedures. Reduced character sets require meristic counts of pectoral fin rays, dorsal fin rays, gill rakers and vertebrae, and morphometric measurements of standard length, pectoral and pelvic fin lengths, body depth and gape width. Regional differences based on these morphometric and meristic sets are substantiated by monomorphism at each MDH locus in Scottish fish in contrast to polymorphism at the MDH-1 and MDH-3 loci in Newfoundland fish. Only the morphometric discriminant function is highly accurate (>80%) in identifying home river origins of the fish examined with the discriminating power increasing with increased fish size. These findings for juvenile fish indicate that, while meristic, morphometric and electrophoretic criteria provide a likely means for distinguishing regional fish stocks, morphometric character sets would seem to offer the best possibility for identifying home river origins of adult Atlantic salmon in mixed fisheries.  相似文献   

16.
This study aimed to determine the lowest effective concentration (LEC) of 2‐phenoxyethanol (2‐Phe) and essential oils (EOs) of Melaleuca alternifolia and Ocimum gratissimum able to induce anaesthesia in Astyanax bimaculatus. LEC was assumed to be the required concentration to carry out anaesthesia in less than 3 min with recovery in <5 min and sufficient to carry out routine aquaculture procedures. The following concentrations were tested: 2‐Phe (100, 200, 300, 400, 500 and 600 µl/L); M. alternifolia (200, 300, 400, 500 and 600 µl/L); and O. gratissimum (10, 20, 30, 40, 50, 60, 70, 100, 150, 250 and 300 µl/L). Results show that all three agents evaluated have effective anaesthetic properties for use in Astyanax bimaculatus with LEC for 2‐Phe, M. alternifolia and O. gratissimum of 200, 300 and 60 µl/L respectively.  相似文献   

17.
The freshwater crayfish industry in Britain is based on two species, Pacifastacus leniusculus (Dana) and Astacus leptodactylus Eschscholtz, which were introduced during the 1970s and 1980s. The former is widely cultivated but both are also established in the wild, from where they are harvested. Very few studies have been made of the meat yield in these two species and none on British populations. Two essentially wild populations were assessed for their meat yield. Due to its more massive claws male P. leniusculus had a higher meat yield than male and female A. leptodactylus and female P. leniusculus in both winter and summer months. Less difference was found between the yield of tail meat between the sexes and species. Compared with other studies, meat yield in the two British populations of P. leniusculus (11–15%) and A. leptodactylus (9–13%) would appear to be lower; possible reasons for this are discussed. However, expressing meat yield as a percentage of wet body weight, although useful for comparative purposes, can give conflicting results – examples of this are given. Meat yields from the claws of the two species indicated that positive allometric growth continued after sexual maturity.  相似文献   

18.
Life history theory seeks to explain how environmental variation selects for patterns of investment in growth and survival relative to production and survival of offspring. Seasonal variations in rainfall and temperature provide environmental cues for spawning by many tropical freshwater fishes. To investigate environment–life history associations, we conducted a one‐year study of Astyanax intermedius in an Atlantic Forest stream of southeastern Brazil. Our analysis focused on temporal variation in feeding, body condition and reproduction in relation to rainfall and water temperature. For mature females, food intake was not significantly correlated with rainfall or temperature; however, body condition was negatively correlated with rainfall and water temperature. Female reproductive effort was positively correlated with water temperature, but did not vary with rainfall. For males and juveniles, there was no significant relationship between food intake or body condition and either environmental variable. Testis weight was negatively correlated with rainfall, but was not significantly correlated with water temperature. We detected a negative correlation between gonad mass with body condition and food intake for females but not for males. Our results differed from other studies in tropical and subtropical areas where rainfall has been shown to be positively correlated with fish reproductive effort. Our results indicate that reproductive effort of males is relatively constant throughout the year, whereas for females, it increases with increasing water temperature. This increase in reproductive investment in concert with an increasing temperature and metabolic rate may incur a trade‐off with somatic growth and survival for this small stream fish.  相似文献   

19.
This work aimed to evaluate the probiotic Lactobacillus spp. in the microbiota of Astyanax bimaculatus reared in a water recirculation system. The experiment was randomized, using 800 postlarvae distributed into eight polyethylene containers, separated into two treatments, in quadruplicate: supplementation with Lactobacillus spp. (Probiotic) and no supplementation (Control). After 90 days of culture, 13 fish per container were anaesthetized. Three of these underwent microbiological evaluation, and haematological analyses were carried out on five. Immunological assessment was performed on another five fish. Zootechnical parameters were evaluated for all animals. In the microbiological evaluation, the probiotic group presented higher counts of lactic acid bacteria, but lower counts of Vibrio spp., Pseudomonas spp., and Staphylococcus spp., when compared with control. After haematological analysis, the supplemented group presented low haematimetric indices of Mean Corpuscular Haemoglobin Concentration and Mean Corpuscular Haemoglobin (MCHC and MCH, respectively) and higher amounts of total leucocytes, thrombocytes and circulating monocytes when compared with control. The immunological profile did not differ between treatments. In the zootechnical performance, probiotic group presented higher productivity, survival and apparent food efficiency when compared with control. Therefore, when Lactobacillus spp. was supplemented in the diet of A. bimaculatus, immunocompetence and the zootechnical performance of animals increased.  相似文献   

20.
为研究罗氏沼虾(Macrobrachium rosenbergii)养殖群体表型性状间的相互关系及不同类群间的性状差异,本研究对人工养殖的罗氏沼虾雌、雄及“老头虾”3个类群共490个个体的体重、体长、全长等12个表型性状进行了相关分析、形态性状对体重影响的通径分析等。结果表明, 3个类群除上、下额刺数2个可数性状外,其他9个可量形态性状与体重都呈极显著的正相关(P<0.01);影响体重的关键形态性状在3个类群中各不相同,但体长、头胸甲长、第二步足长在3个类群中均是影响体重的关键指标;分别建立了各类群体重与关键形态性状的多元回归方程。聚类分析和主成分分析结果表明,雌、雄2个类群表型上更为相似,“老头虾”与雌性个体的差异最大。腹部轮廓特征(包括腹长、腹宽、腹高)、全长、体长及第二步足长对3个类群的差异贡献较大。雌性个体腹部发达,“老头虾”则第二步足尤为发达。本研究结果可为罗氏沼虾的选择育种、基础生物学及行业标准的制定提供数据资料。  相似文献   

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