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Acipenser sinensis and Acipenser dabryanus are critically endangered species, so germplasm conservation via cryopreservation of sperm is necessary. Disaccharides can act as membrane‐impermeable cryoprotectants, and enolase3 (ENO3) and plasma membrane Ca2+ ATPase isoform (PMCA2) are proteins associated with sperm quality. We considered seven characteristics of sperm quality in cultured brood stock from A. sinensis and A. dabryanus. We tested use of sucrose or trehalose alone and in combination at different concentrations for cryopreservation of A. dabryanus sperm. A low concentration of sucrose plus trehalose (S15T15) was optimal. Mixing of the extender with sucrose, lactose, or trehalose alone or with pairwise mixtures revealed that a mixture of lactose and trehalose (L15T15) gave the best results for both A. sinensis and A. dabryanus. Enolase3 and PMCA2 expression levels were measured in cryopreserved A. sinensis sperm via Western blotting. Relative ENO3 and PMCA2 expression levels were examined, and the relationship between disaccharide composition, sperm quality and protein expression was explored in A. sinensis. The results showed that relative ENO3 and PMCA2 expression levels were the highest at L15T15 in cryopreserved A. sinensis sperm. There were significant positive correlations between ENO3 expression and percentage membrane integrity, and between PMCA2 expression and sperm motility parameters (percentage of motile sperm, curvilinear velocity, straight‐line velocity and average path velocity; p < .05) in cryopreserved A. sinensis sperm. Our results indicate the optimal disaccharide combination and concentrations for cryopreservation of A. sinensis and A. dabryanus sperm and suggest that ENO3 and PMCA2 expression levels could serve as a valuable indicator of sperm quality in A. sinensis.  相似文献   
2.
Effects on prediction of analysing a multi-line chicken population as one line were evaluated. Body weight records were provided by Cobb-Vantress for two lines of broiler chickens. Phenotypic records for 183 695 and 164 149 broilers and genotypic records for 3195 and 3001 broilers were available for each line. Lines were combined to create a multi-line population and analysed using a single-step procedure combining the additive relationship matrix and the genomic relationship matrix (G). G was scaled using allele frequencies from each line, the multi-line population, or 0.5. When allele frequencies were calculated from each line, distributions of diagonal elements were bimodal. When allele frequencies were calculated from the multi-line population, the distribution of diagonal elements had one peak. When allele frequency 0.5 was used, the distribution was bimodal. Genomic estimated breeding values (GEBVs) were predicted using each allele frequency. GEBVs differed with allele frequency but had ≥ 0.99 correlations with GEBVs predicted with correct allele frequencies. Means of each line and differences in mean between the lines differed based on allele frequencies. Assumed allele frequencies have little impact on ranking within line but larger impact on ranking across lines. G may be used to evaluate multiple populations simultaneously but must be adjusted to obtain properly scaled estimates when population structure is unknown.  相似文献   
3.
Genetic parameters of traits related to hepatic lipid metabolism, carcass composition, and product quality of overfed mule ducks were estimated on both parental lines of this hybrid: the common duck line for the maternal side and the Muscovy line for the paternal side. The originality of the statistical model was to include simultaneously the additive genetic effect of the common ducks and that of the Muscovy ducks, revealing a greater genetic determinism in common than in Muscovy. Plasma metabolic indicators (glucose, triglyceride, and cholesterol contents) were heritable, in particular at the end of the overfeeding period, and heritabilities increased with the overfeeding stage. Carcass composition traits were highly heritable in the common line, with values ranging from 0.15 for liver weight, 0.21 for carcass weight, and 0.25 for abdominal fat weight to 0.32 for breast muscle weight. Heritabilities of technological outputs were greater for the fatty liver (0.19 and 0.08, respectively, on common and Muscovy sides for liver melting rate) than for the pectoralis major muscle (between 0.02 and 0.05 on both parental sides for cooking losses). Fortunately, the processing industry is mainly facing problems in liver quality, such as too high of a melting rate, than in meat quality. The meat quality appraisal criteria (such as texture and cooking losses), usually dependent on pH and the rate of decline of pH, were also very lowly heritable. This study demonstrated that genetic determinism of meat quality and ability of overfeeding is not similar in the common population and in the Muscovy population; traits related to fattening, muscle development, and BW have heritability values from 2 to 4 times greater on the common line than on the Muscovy line, which is relevant for considering different selection strategies.  相似文献   
4.
Accurate prediction of breeding values depends on capturing the variability in genome sharing of relatives with the same pedigree relationship. Here, we compare two approaches to set up genomic relationship matrices for precision of genomic relationships (GR) and accuracy of estimated breeding values (GEBV). Real and simulated data (pigs, 60k SNP) were analysed, and GR were estimated using two approaches: (i) identity by state, corrected with either the observed ( G VR ‐O ) or the base population ( G VR ‐B ) allele frequencies and (ii) identity by descent using linkage analysis ( G IBD ‐L ). Estimators were evaluated for precision and empirical bias with respect to true pedigree IBD GR. All three estimators had very low bias. G IBD ‐L displayed the lowest sampling error and the highest correlation with true genome‐shared values. G VR ‐B approximated G IBD ‐L 's correlation and had lower error than G VR ‐O . Accuracy of GEBV for selection candidates was significantly higher when G IBD ‐L was used and identical between G VR ‐O and G VR ‐B . In real data, G IBD ‐L 's sampling standard deviation was the closest to the theoretical value for each pedigree relationship. Use of pedigree to calculate GR improved the precision of estimates and the accuracy of GEBV.  相似文献   
5.
The fatty liver of mule ducks (i.e., French "foie gras") is the most valuable product in duck production systems. Its quality is measured by the technological yield, which is the opposite of the fat loss during cooking. The purpose of this study was to determine whether biochemical measures of fatty liver could be used to accurately predict the technological yield (TY). Ninety-one male mule ducks were bred, overfed, and slaughtered under commercial conditions. Fatty liver weight (FLW) and biochemical variables, such as DM, lipid (LIP), and protein content (PROT), were collected. To evaluate evidence for nonlinear fat loss during cooking, we compared regression models describing linear and nonlinear relations between biochemical measures and TY. We detected significantly greater (P = 0.02) linear relation between DM and TY. Our results indicate that LIP and PROT follow a different pattern (linear) than DM and showed that LIP and PROT are nonexclusive contributing factors to TY. Other components, such as carbohydrates, other than those measured in this study, could contribute to DM. Stepwise regression for TY was performed. The traditional model with FLW was tested. The results showed that the weight of the liver is of limited value in the determination of fat loss during cooking (R(2) = 0.14). The most accurate TY prediction equation included DM (in linear and quadratic terms), FLW, and PROT (R(2) = 0.43). Biochemical measures in the fatty liver were more accurate predictors of TY than FLW. The model is useful in commercial conditions because DM, PROT, and FLW are noninvasive measures.  相似文献   
6.
Genomic relationships based on markers capture the actual instead of the expected (based on pedigree) proportion of genome shared identical by descent (IBD). Several methods exist to estimate genomic relationships. In this research, we compare four such methods that were tested looking at the empirical distribution of the estimated relationships across 6704 pairs of half‐sibs from a cross‐bred pig population. The first method based on multiple marker linkage analysis displayed a mean and standard deviation (SD) in close agreement with the expected ones and was robust to changes in the minor allele frequencies (MAF). A single marker method that accounts for linkage disequilibrium (LD) and inbreeding came second, showing more sensitivity to changes in the MAF. Another single marker method that considers neither inbreeding nor LD showed the smallest empirical SD and was the most sensible to changes in MAF. A higher mean and SD were displayed by VanRaden's method, which was not sensitive to changes in MAF. Therefore, the method based on multiple marker linkage analysis and the single marker method that considers LD and inbreeding performed closer to theoretical values and were consistent with the estimates reported in literature for human half‐sibs.  相似文献   
7.
In this study, the potential association of PrP genotypes with ewe reproductive traits and lamb growth traits was investigated. Data were included on ewes and lambs of the INRA 401 breed from the Bourges-La Sapinière INRA experimental farm. This breed was chosen because of good breeding (prolificacy and maternal abilities) and carcass qualities, and the large number of available animals with performance records and PrP genotypes. Ewes were categorized into 3 PrP genotype classes: ARR homozygous, ARR heterozygous, and animals without any ARR haplotype. Two analyses differing in the traits considered were carried out. Firstly, the potential association of the PrP genotype of ewes with their reproduction traits (fertility, litter size, and ovulation rate) was studied. The data included 801, 779, and 587 genotyped ewes for fertility, litter size, and ovulation rate, respectively. Secondly, the association of the PrP genotype of the ewes with growth traits of their lambs (birth weight, ADG between 10 and 30 d of age) was investigated. The data included 3,749 and 3,512 lambs for birth weight and ADG, respectively. The different traits were analyzed using an animal model, where the PrP genotype effect was included as a fixed effect. The reproductive traits were modeled under a probit or a threshold approach. The results of this study indicate no evidence of an association between PrP genotypes and reproductive and growth traits. It is unlikely that selection for scrapie resistance will have an effect on the reproductive or performance traits studied in the INRA 401 breed.  相似文献   
8.
High levels of reactive oxygen species (ROS), which may be associated with reduced sperm quality, can be detected during cryopreservation of sperm of some species. Our objective was to investigate whether the addition of antioxidants to cryopreservation extenders influenced post‐thaw sperm characteristics and fertility in Acipenser dabryanus, Acipenser sinensis and Acipenser baerii. Prior to freezing, sperm samples were diluted with a base extender as control or in extender supplemented with catalase (CAT), glutathione (GSH), cysteine (NAC), ascorbic acid (VC) or their paired combinations. Protective concentrations of CAT, GSH and VC in the three species were 25 U/ml, 0.25‐0.5 mg/ml and 0.5 mg/ml, respectively. Cysteine showed no protective effect against ROS. The addition of CAT, GSH and VC positively affected either acrosome or membrane integrity of post‐thawed sperm in the three species, as well as spermatozoan motility in A. sinensis. The combination of antioxidants did not show a positive synergistic effect. This study suggested that the use of antioxidants in the cryopreservation of sturgeon sperm has potential to decrease intracellular ROS, and consequently preserve acrosome and membrane integrity, as well as spermatozoan motility.  相似文献   
9.
KS Cheng  ZG Dai  DM Wei  T Lu 《Science (New York, N.Y.)》1998,280(5362):407-409
The unusual hard x-ray burster GRO J1744-28 recently discovered by the Compton Gamma-Ray Observatory can be modeled as a strange star with a dipolar magnetic field of 相似文献   
10.
In single‐step genomic evaluation using best linear unbiased prediction (ssGBLUP), genomic predictions are calculated with a relationship matrix that combines pedigree and genomic information. For missing pedigrees, unknown selection processes, or inclusion of several populations, a BLUP model can include unknown‐parent groups (UPG) in the animal effect. For ssGBLUP, UPG equations also involve contributions from genomic relationships. When those contributions are ignored, UPG solutions and genetic predictions can be biased. Options to eliminate or reduce such bias are presented. First, mixed model equations can be modified to include contributions to UPG elements from genomic relationships (greater software complexity). Second, UPG can be implemented as separate effects (higher cost of computing and data processing). Third, contributions can be ignored when they are relatively small, but they may be small only after refinements to UPG definitions. Fourth, contributions may approximately cancel out when genomic and pedigree relationships are constructed for compatibility; however, different construction steps are required for unknown parents from the same or different populations. Finally, an additional polygenic effect that also includes UPG can be added to the model.  相似文献   
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