The hearing abilities of the silver carp (Hypopthalmichthys molitrix) and bighead carp (Aristichthys nobilis)

Concern regarding the spread of silver carp (Hypopthalmichthys molitrix) and bighead carp (Aristichthys nobilis) through the Illinois River has prompted the development of a Bio-acoustic Fish Fence (BAFF) to act as an acoustic fish deterrent. The application of this technology has resulted in a need to understand the auditory physiology of the target species, in order to maximise the effect of the barrier in preventing the migration of the non-indigenous carp species into Lake Michigan, whilst minimising the effect on indigenous fish populations. Therefore, the hearing thresholds of 12 H. molitrix and 12 A. nobilis were defined using the Auditory Brainstem Response (ABR) technique, in a pressure-dominated sound field generated by submerged transducers of the type used in the construction of the BAFF system. The results clearly show that these fish are most sensitive to sounds in a frequency bandwidth of between 750 Hz and 1500 Hz, with higher thresholds below 300 Hz and above 2000 Hz.     

Sixteen polymorphic microsatellites in bighead carp (Aristichthys nobilis) and cross-amplification in silver carp (Hypophthalmichthys molitrix)

A (GT)(n) enriched partial genomic library of bighead carp (Aristichthys nobilis) was constructed by employing the (fast isolation by AFLP of sequences containing repeats) FIASCO protocol. Sixteen loci exhibited polymorphism with two to seven alleles/locus (mean 3.263) in a test population and the observed heterozygosity ranging from 0.100 to 0.690 (mean 0.392). Eleven of the 16 bighead carp microsatellites were found to be also polymorphic in silver carp. These polymorphic loci should provide sufficient level of genetic diversity to evaluate population structure of bighead carp.     

Polymorphisms in the ovine myostatin gene (MSTN) and their association with growth and carcass traits in New Zealand Romney sheep

Myostatin is a regulator of myogenesis and has been implicated in the regulation of adiposity and in controlling the structure and function of tendons. Polymerase Chain Reaction Single-Stranded Conformational Polymorphism (PCR-SSCP) analysis of intron-1 was used to identify five variants (designated A-E) of the myostatin gene ( MSTN ). The effect of this genetic variation on growth and carcass traits was investigated in 517 Romney male lambs from 17 sire-lines, born on a South Island New Zealand farm. General linear mixed effect models revealed that the presence of allele A in a lamb's genotype was associated with decreased leg, loin and total yield of lean meat, whereas the presence of allele B was associated with increased loin yield and proportion loin yield (loin yield divided by total yield expressed as percentage). The effect of the number of allele copies present was investigated, and it was found that the absence of A , or the presence of two copies of B , was associated with increased mean leg yield, loin yield and total yield. Two copies of B were also associated with a decrease in proportion of shoulder yield, whereas two copies of A were associated with a decrease in proportion of loin yield. Associations with allele C were not detected. No associations of MSTN variation with birth weight, weaning weight, pre-weaning growth rate, draft age and hot carcass weight (H-W) were detected. These results suggest that variation in ovine MSTN is associated with meat production, but not birth weight or growth rate in New Zealand Romney sheep.     

Comparative studies on the feeding selectivity of silver carp Hypophthalmichthys molitrix and bighead carp Aristichthys nobilis

Silver carp and bighead carp exhibited size-selection for food particles in aquarium experiments, but did not select their preferred species of plankton actively when they were distributed evenly in the water. They also possessed the capacity of selection for feeding area. The removal rates (% g⁻¹ fish weight) of silver carp for smaller plankton (phytoplankton) were higher than those of bighead carp. The removal rates by the latter for bigger plankton (zooplankton) were higher than those of silver carp, but for plankton about 70 μm dia. the rates by the two species were almost equal.     

Temperature preference and tolerance of hybrid carp (female grass carp,Ctenopharyngodon idella x male bighead,Aristichthys nobilis)

Synopsis This study examined the effects of various pH values on sperm motility times of white suckers,Catostomus commersoni, from two artificially acidified lakes in the Experimental Lakes Area (ELA), northwestern Ontario. White sucker sperm were active (motile) in water at all pH values tested (3.0–7.0). The maximum sperm motility time was 76.9 seconds and the minimum time was 51.9 seconds. Sperm motility times of fish from Lake 302N were similar to those of fish from Lake 223 at all pH values except pH 5.0 and 5.5. At these two pH values, sperm motility times of Lake 223 fish were longer than those of Lake 302N fish. In both lakes sperm motility at ambient lake pH levels (Lake 223 + 5.1, Lake 302N + 6.3) were similar to those at pH 7.0. Motility times of all fish tested were within the range of time during which fertilization normally occurs, indicating that reproductive failures in Lake 223 were probably not caused by impairment of sperm motility times.     

Suction volume and filtering efficiency of silver carp (Hypophthalmichthys molitrix Val.) and bighead carp (Aristichthys nobilis Rich.)

Experiments were conducted to measure the suction volume of silver carp and bighead carp of age 1 + with respiratory chamber, and to calculate the suction volume and the filtering efficiency with respect to changes in concentrations of food particles. Suction volume (B. ml/mouth) and filtering efficiency (E. %) were calculated using the following formula: C ₁=C₀(1-BE/v)ⁿ where C₀ and C₁ were the concentrations of specific food particles at the beginning and at the end of experiment, respectively, V was the volume (ml) of experimental water, and n was the total number of observation of suction made during the experimental period. The relationships between suction volume (ml/mouth) of age I+ silver carp (B_h) and bighead carp (B_a) and their standard lengths (L, cm) were: B _h=0.561L-8.94, B_a= 0.627L-7.48 while those of the fingerlings were: B _h= O.l70L-0.837, B_a= 0.157L-0.418. The suction volume of the fingerlings was mainly affected by fish size, the function of temperature between 15 and 25° C being negligible. However, temperature affected filtering rate (filtered volume per unit time) through its effect on filtering frequency. The filtering efficiency of the fishes for rotifers (Brachionus caliciflorus) was 100 per cent. The relationships between filtering efficiency and sizes of food particles smaller than or equal to that of a rotifer were: E _h=25.1 ln e.s.d. -13.6, E_a=22.2 In e.s.d. -33.1 where E_h and E_a were filtering efficiency of silver carp and bighead carp, respectively, and e.s.d. was the equivalent spherical diameter (μm) of food particles.     

Food intake and growth of hybrid carp (female grass carp, Ctenopharyngodon idella× male bighead, Aristichthys (Hypophthalmichthys) nobilis) fed on zooplankton and Chara

Hybrid carp were raised in 1651 indoor tanks. Two tanks were used in this study each stocked with five fish (average total length and weight = 235.7 mm; 116.1 g); one tank was provided with zooplankton and the other with zooplankton and Chara sp. The hybrids fed actively on zooplankton at an average daily rate of 39% and Chara at 2.6% by body weight. Growth was estimated as 0.36% (0.43 g) per day. The hybrids on the two food types showed no significant differences either in plankton consumption or growth rate.     

Development of microsatellite DNA markers of silver carp (Hypophthalmichthys molitrix) and their cross‐species application in bighead carp (Aristichthys nobilis)

Forty‐four microsatellite DNA markers were developed for silver carp, and used to investigate polymorphisms of 41 wild silver carps and seven wild bighead carps collected from Jingzhou fragment of Yangtze River. In silver carp, 40 markers were polymorphic. A total of 297 alleles were detected at 40 polymorphic loci. The number of alleles per locus varied from two to 16 with an average of 7.4 and the expected heterozygosities of each locus ranged from 0.07 to 0.91 with an average of 0.69. All markers amplified both silver carp and bighead carp DNAs.     

Development of silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) genetic maps using microsatellite and AFLP markers and a pseudo-testcross strategy

Silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) are two of the four most important pond-cultured fish species inhabiting the major river basins of China. In the present study, genetic maps of silver carp and bighead carp were constructed using microsatellite and AFLP markers and a two-way pseudo-testcross strategy. To create the maps, 60 individuals were obtained from a cross of a single bighead carp (female) and a single silver carp (male). The silver carp map consisted of 271 markers (48 microsatellites and 223 AFLPs) that were assembled into 27 linkage groups, of which 22 contained at least four markers. The total length of the silver carp map was 952.2 cM, covering 82.8% of the estimated genome size. The bighead carp map consisted of 153 markers (27 microsatellites and 126 AFLPs) which were organized into 30 linkage groups, of which 19 contained at least four markers. The total length of the bighead carp map was 852.0 cM, covering 70.5% of the estimated genome size. Eighteen microsatellite markers were common to both maps. These maps will contribute to discovery of genes and genetic regions controlling traits in the two species of carp.     

Food passage time and daily ration of bighead carp,Aristichthys nobilis,kept in cages

Synopsis The food passage time of bighead carp weighing 13 to 2850 g was 7.1 to 12.8 h and the daily food ration was 5.7 to 2% of body weight at water temperatures ranging from 21 to 28.5°C. Food passage time tended to be shorter for larger fish because the speed of passage was substantially higher for the larger fish: 323 mm h^–1 for the larger fish and 67 mm h^–1 for smaller fish. Gut length increased with increased body length. Relative gut length showed great variability. It increased with increasing fish body length up to about 250 mm and remained similar for larger fish.     

A second‐generation genetic linkage map for bighead carp (Aristichthys nobilis) based on microsatellite markers

Bighead carp (Aristichthys nobilis) is an important aquaculture fish worldwide. Genetic linkage maps for the species were previously reported, but map resolution remained to be improved. In this study, a second‐generation genetic linkage map was constructed for bighead carp through a pseudo‐testcross strategy using interspecific hybrids between bighead carp and silver carp. Of the 754 microsatellites genotyped in two interspecific mapping families (with 77 progenies for each family), 659 markers were assigned to 24 linkage groups, which were equal to the chromosome numbers of the haploid genome. The consensus map spanned 1917.3 cM covering 92.8% of the estimated bighead carp genome with an average marker interval of 2.9 cM. The length of linkage groups ranged from 52.2 to 133.5 cM with an average of 79.9 cM. The number of markers per linkage group varied from 11 to 55 with an average of 27.5 per linkage group. Normality tests on interval distances of the map showed a non‐normal marker distribution; however, significant correlation was found between the length of linkage group and the number of markers below the 0.01 significance level (two‐tailed). The length of the female map was 1.12 times that of the male map, and the average recombination ratio of female to male was 1.10:1. Visual inspection showed that distorted markers gathered in some linkage groups and in certain regions of the male and female maps. This well‐defined genetic linkage map will provide a basic framework for further genome mapping of quantitative traits, comparative mapping and marker‐assisted breeding in bighead carp.     

黄颡鱼MSTN基因多态性及其与生长性状的相关性分析

肌肉生长抑制素基因(Myostatin,MSTN)属于转化生长因子β家族,其主要功能是负向调控肌肉的生长发育。采用PCR-SSCP技术对黄颡鱼MSTN基因进行单核苷酸多态性检测和分型,并与其生长性状进行关联分析。结果表明,在第一内含子部分检测到1个缺失位点和2个突变位点(T1003del、G1022A和T1063G),基因型分别为:AA、AB、CC、CD和DD;在第三外显子部分检测到1个突变位点(T132C),基因型分别为:EE和EF。关联性分析表明,AA基因型个体的全长、体长、体高、体厚、头长和体重显著大于CD和DD基因型(P<0.05),AA基因型雌性个体的全长、体长、体高、体厚、头长、尾柄高、尾柄厚和体重也显著大于DD基因型(P<0.05)。由此推断,AA基因型是影响雌性黄颡鱼生长性状的有利基因型,DD基因型是影响雌性黄颡鱼生长性状的不利基因型,可以尝试利用这两个位点对雌性黄颡鱼进行标记辅助选育。     

Effect of nematode Panagrellus redivivus density on growth, survival, feed consumption and carcass composition of bighead carp Aristichthys nobilis (Richardson) larvae

The study aimed to determine the optimum density of free‐living nematodes in feeding bighead carp, Aristichthys nobilis, larvae. In the first experiment, carp stocked at 25 larvae L^?1 were fed varying levels of nematodes (50, 75, 100, 125 and 150 per ml) twice a day for 21 days from the start of exogenous feeding. Final body weight was significantly higher (P < 0.05) in larvae fed 125 and 150 nematodes per ml than in those fed 50 and 75 per ml, but survival was low (61.8 and 63.6%, respectively). Survival rate was highest in larvae fed 100 nematodes ml^?1 (81.3%). Carcass analysis showed that larvae fed 125 and 150 nematodes ml^?1 had significantly lower body protein and higher body lipid than those fed other nematode densities. Carcass ash was similar for larvae fed 50–100 nematodes ml^?1 but it decreased significantly at the higher nematode densities. Carp larvae in a subsequent experiment were given 50, 75 and 100 nematodes ml^?1 per feeding. Newly hatched Artemia was the control feed. Nematode consumption and growth of the larvae were determined. Larvae were sampled at intervals of 2–4 days and the nematodes in the gut were counted and measured. At each nematode density, the number of nematodes present in the gut of the larvae increased significantly with time. At each sampling day, the number of nematodes in the gut did not differ significantly among treatments (P > 0.05) although it tended to increase with nematode density at day 2 and day 4 but decrease at day 7 onward. The carp larvae consumed significantly shorter nematodes on day 2 and day 4 than on the succeeding sampling days regardless of nematode density. However, the length of nematodes in the gut of the larvae did not differ significantly among the nematode densities. The final body weight of larvae increased with increasing nematode density. The body weight of larvae fed 100 nematodes ml^?1 did not differ significantly from that of larvae given Artemia nauplii. Results show that bighead carp larvae should be fed 100 free‐living nematodes per ml at each feeding time.     

A note on the growth of two exotics in England; the silver carp (Hypophthalmichthys molitrix Val.) and the bighead (Aristichthys nobilis Rich.)

Observations were made on the growth of microphagous silver carp and bigheads in a tank housed under a horticultural polythene tunnel. It is suggested that the species may be of interest for cultivation and might also be useful in removing nutrients from eutrophic waters in the United Kingdom.     

Comparison of early developmental stages and adults of grass carp, Ctenopharyngodon idella, and hybrid carp (female grass carp × male bighead Aristichthys nobilis)

Hybrid carp and grass carp from the zygote to the prolarval stage and adults were compared to establish distinguishing characteristics. Zygote diameter, yolk sac and embryo length were not different between the fishes. Body pigmentation patterns showed distinct separation among the prolarvae of the hybrids and grass carp. Total and preanal myomeres were higher in grass carp larvae than in the hybrids. The grass carp and hybrid larvae also differed in 38% of the proportional morphometric characters.
Average meristic counts of adults were significantly higher in hybrids compared with grass carp. Adults of the two fishes showed significant differences in 63% of the proportional morphometric measurements. Gill raker counts showed no overlap and lateral line scales were smaller and more numerous in the hybrid adults.     

Biochemical genetic comparison of bighead (Hypophthalmichthys molitrix), silver carp (Aristichthys nobilis), and their hybrids reared in Czechoslovakia

Incidental and/or uncontrolled hybridization between silver carp ( Hypophthalmichthys molitrix ) and bighead ( Aristichthys nobilis ) represents a serious problem in Czechoslovak aquaculture. This fact affects fitness traits very negatively in successive generations of hybrids. To solve this problem, 1076 individuals in a total of both H. molitrix. A. nobilis , and their hybrids in 12 groups from six rearing facilities were analysed. Twelve protein systems representing 21 presumptive loci were studied to analyse the electrophoretic patterns of their products using horizontal starch gel electrophoresis of blood and tissue extracts. Both species displayed identical electrophoretic patterns in MYO-I* , LDH-A *, LDH-B *, sMDH-1 *, sIDHP-3*, GPI-1*, and CK-I * loci. For a reliable differentiation of both species products of the following nine loci are applicable ALB *, PA *, TF, sMDH-2 *, SOD *, NDH *, MYO-IF , MYO-III *, and CK-2 *. In addition, some polymorphic variants in slDHP-1 *, sIDHP-2 *, LDH-C *, EST-II *, and GPI-2 * loci are of use as auxillary markers while the other variants are common to both species. A high level of gene introgression was evident through hybridization between both species. All groups declared previously as ' H. molifrix ' were actually confirmed biochemically to be H. molitrix . However, all groups declared as ' A. nobilis ' were proved to be a mixture of A. nobilis and its hybrids of different level with H. molitrix . This suggests it is impossible to distinguish between A. nobilis and hybrids using their external morphology only.     

Molecular characterization of glutathione peroxidase gene from the liver of silver carp, bighead carp and grass carp

The cDNAs encoding glutathione peroxidase (GPx) were cloned and sequenced from the liver of three Chinese carps with different tolerance to hepatotoxic microcystins, phytoplanktivorous silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis), and herbivorous grass carp (Ctenopharyngodon idellus). Using genome walker method, a 750 bp 5'-flanking region of the silver carp GPx gene was obtained, and several potential regulatory elements were identified in the promoter region of the GPx gene. The silver carp GPx gene was widely expressed in all tissues examined. Despite phylogenetic analysis, assigning this newly described carp GPx to the group of mammalian GPx2, the carp GPx seems more similar to GPx1 from a physiological point of view. The constitutive expression pattern of the three carp liver GPx gene, shows a positive relationship with their tolerance to microcystins.