[Research progress on early warning model of influenza].

Influenza is an acute respiratory infectious disease caused by influenza virus. It usually exhibits seasonal transmission, but the novel influenza strain can lead to a pandemic with severe human health and socioeconomic consequences. Early warning of influenza epidemic is an important strategy and means for influenza prevention and control. On the basis of reviewing the main influenza surveillance and early warning systems, this study summarizes the principles, applications, advantages and disadvantages, and development prospects of common influenza early warning models, in order to provide reference for research and application of early warning technology for influenza and other acute respiratory infectious diseases.

[Evaluation of demand of resources for laboratory testing and prevention and control of COVID-19 in the context of global pandemic].

Objective: To rapidly evaluate the level of healthcare resource demand for laboratory testing and prevention and control of corona virus disease 2019 (COVID-19) in different epidemic situation, and prepare for the capacity planning, stockpile distribution, and funding raising for infectious disease epidemic response. Methods: An susceptible, exposed, infectious, removed infectious disease dynamics model with confirmed asymptomatic infection cases and symptomatic hospitalized patients was introduced to simulate different COVID-19 epidemic situation and predict the numbers of hospitalized or isolated patients, and based on the current COVID-19 prevention and control measures in China, the demands of resources for laboratory testing and prevention and control of COVID-19 were evaluated. Results: When community or local transmission or outbreaks occur and total population nucleic acid testing is implemented, the need for human resources is 3.3-89.1 times higher than the reserved, and the current resources of medical personal protective equipment and instruments can meet the need. The surge in asymptomatic infections can also increase the human resource demand for laboratory testing and pose challenge to the prevention and control of the disease. When vaccine protection coverage reach ≥50%, appropriate adjustment of the prevention and control measures can reduce the need for laboratory and human resources. Conclusions: There is a great need in our country to reserve the human resources for laboratory testing and disease prevention and control for the response of the possible epidemic of COVID-19. Challenges to human resources resulted from total population nucleic acid testing and its necessity need to be considered. Conducting non-pharmaceutical interventions and encouraging more people to be vaccinated can mitigate the shock on healthcare resource demand in COVID-19 prevention and control.

Assessment of adrenomedullin and proadrenomedullin as predictors of mortality in septic patients: A systematic review and meta-analysis.

OBJECTIVE: To ascertain the ability of adrenomedullin (ADM) and proadrenomedullin (proADM) to predict mortality in sepsis patients. DESIGN: A systematic literature search was made of the PubMed, EMBASE, Cochrane and China National Knowledge Infrastructure (CNKI) databases before May 2017, supplemented by manual searches of references. A meta-analysis of high-quality clinical studies was subsequently performed to assess the association between ADM/proADM and mortality risk among patients with sepsis. PATIENTS: Thirteen studies involving 2556 patients were included in the study. INTERVENTIONS: Two reviewers independently identified articles, extracted data, assessed quality and cross-checked the results. The predictive values of ADM and proADM referred to mortality were assessed by relative risk (RR). The overall diagnostic accuracy of ADM and proADM in application to sepsis was pooled according to a bivariate model. Publication bias was assessed using Deek's funnel plot asymmetry test. RESULTS: Elevated ADM or proADM levels were associated with increased mortality (pooled RR=3.31; 95%CI 2.31-4.75). Subgroup analyses indicated the pooled RRs were 3.12 (95%CI 1.75-5.56) and 3.43 (95%CI 2.21-5.31) for ADM and proADM, respectively. The pooled sensitivity and specificity were 0.72 (95%CI 0.64-0.78) and 0.77 (95%CI 0.69-0.83), respectively. The overall area under the summary receiver operating characteristic (SROC) curve was 0.80 (95%CI 0.77-0.84). Publication bias was not statistically significant. CONCLUSIONS: Both ADM and proADM might serve as useful markers for predicting the prognosis of sepsis.

Isolation and characterization of polymorphic microsatellite markers for the chub mackerel (Scomber japonicus) and cross-species amplification in the blue mackerel (S. australasicus).

In this study, 10 polymorphic microsatellite markers were developed in Scomber japonicus and were examined on 30 individuals collected from the North Pacific. The number of alleles per locus ranged from 4 to 17. The observed and expected heterozygosities per locus ranged from 0.2759 to 0.8621 and from 0.43071 to 0.9177, respectively. The polymorphism information content (PIC) was from 0.3931 to 0.8939. One locus showed moderate polymorphism (0.25 < PIC < 0.5), while the rest were highly polymorphic (PIC > 0.5). Two loci showed significant deviation from Hardy-Weinberg equilibrium after Bonferroni corrections (P < 0.005). No linkage disequilibrium was detected among the loci. Results of cross-species amplification showed that 10 microsatellite markers were successfully amplified in 29 individuals of S. australasicus and 9 indicated polymorphisms. These markers will be useful for investigating the genetic structure, gene flow, and species identification of S. japonicus and S. australasicus, its closely related species.

RESEARCH ARTICLE Molecular cloning and expression analysis of a matrix Gla protein gene in the spinyhead croaker, Collichthys lucidus.

The matrix Gla (gamma-carboxyglutamic acid-rich) protein (MGP), a vitamin K-dependent and Gla-containing protein, is a calcification inhibitor that mainly functions in tissue calcification and mineralization. In this study, we obtained the complete cDNA sequence of MGP from the spinyhead croaker (Collichthys lucidus), which we named Cl-MGP. Cl-MGP was 923 bp long with a 384-bp open reading fragment that encoded 127 amino acids. The predicted MGP protein sequence contained a 19-residue hydrophobic signal peptide, suggesting that it possesses secretory characteristics. The Gla domain and the invariant unit ErraEtCedyspC, which has been identified in all known vitamin K-dependent vertebrate proteins, were highly conserved in Cl-MGP, suggesting that it uses the same mechanism to function as the known proteins. An alignment analysis revealed that Cl-MGP had the highest identity with Larimichthys crocea (93%), which had lost five amino acid residues in the C-terminal. A quantitative real-time polymerase chain reaction revealed that Cl-MGP expression was highest in the gill, followed by the cholecyst and spleen, with almost no expression in the blood, muscle, or testes. The high Cl-MGP expression in the gill is similar to that observed in other fish species, but the relatively high expression found in the cholecyst and spleen is not seen in all species. Future studies should investigate the tissue distributions of both mRNA and proteins in different species, in order to understand the function and evolution of MGP in different species.

Characterization of the complete mitochondrial genome and phylogenetic relationships of the three-spot swimming crab (Portunus sanguinolentus).

In this study, we determined the whole mitochondrial genome profile of the three-spot swimming crab (Portunus sanguinolentus) and elucidated phylogenetic relationships between representative species in the order Decapoda. The mitochondrial genome was 16,024 bp in length and consisted of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a putative control region. Of the 37 genes, 23 were encoded by the heavy strand while 14 were encoded by the light strand. Four types of start codons were identified; ATG initiated nine genes, ATT initiated two genes, and ATC and GTG each started one gene. Nine protein-coding genes ended with a complete TAA or TAG stop codon, and four genes ended with an incomplete T or TA codon. Fourteen non-coding regions were found, which ranged from 1 to 34 bp in length. Nine overlaps were observed, with lengths between 1 and 7 bp. Phylogenetic analysis suggested that P. sanguinolentus is genetically closest to P. trituberculatus and P. pelagicus. Charybdis feriata, C. japonica, and Thalamita crenata formed a single cluster, and were close to the genera Callinectes and Portunus. Therefore, the genera Charybdis and Thalamita should be classified into the subfamily Portuninae.

Characterization of the complete mitochondrial genome of Portunus pelagicus with implications for phylogenomics.

This study determined the mitochondrial genome structure of the blue swimming crab (Portunus pelagicus), and elucidated its phylogenetic relationships among the species within the order Decapoda. The complete mitochondrial genome was 16,155 bp long, and contained 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 DNA control region. The gene order of the genome was the same as that found within the family Portunidae. Twenty-three genes were on the heavy strand and 14 were on the light strand. Almost all of the protein-coding genes were initiated by an ATG codon, except for three genes (ATP6, ND1, and ND3) that started with a rare ATT codon. Of the 13 protein-coding genes, 10 ended with complete TAA or TAG stop codons and three ended with an incomplete T codon. Thirteen non-coding regions were identified that ranged from 1 to 30 bp in length. Nine overlaps were found, which ranged 1 to 7 bp in length. Phylogenetic analyses based on 12 concatenated protein-coding genes revealed that P. pelagicus formed a monophyletic group with Portunus trituberculatus, which were in a larger group with Callinectes sapidus, while the genera Charybdis and Thalamita formed another group. These two groups clustered together and grouped with the genus Scylla. The phylogenetic analysis supported the inclusion of Charybdis in subfamily Portuninae of the family Portunidae, and revealed a close relationship between Charybdis and Thalamita. We suggest that Thalamita should also be classified into the subfamily Portuninae. The results can be used in the study of phylogenetic, population genetic and conservation genetics of P. pelagicus.

Optimization of selective breeding through analysis of morphological traits in Chinese sea bass (Lateolabrax maculatus).

Determining correlations between certain traits of economic importance constitutes an essential component of selective activities. In this study, our aim was to provide effective indicators for breeding programs of Lateolabrax maculatus, an important aquaculture species in China. We analyzed correlations between 20 morphometric traits and body weight, using correlation and path analyses. The results indicated that the correlations among all 21 traits were highly significant, with the highest correlation coefficient identified between total length and body weight. The path analysis indicated that total length (X1), body width (X5), distance from first dorsal fin origin to anal fin origin (X10), snout length (X16), eye diameter (X17), eye cross (X18), and slanting distance from snout tip to first dorsal fin origin (X19) significantly affected body weight (Y) directly. The following multiple-regression equation was obtained using stepwise multiple-regression analysis: Y = -472.108 + 1.065X1 + 7.728X5 + 1.973X10 - 7.024X16 - 4.400X17 - 3.338X18 + 2.138X19, with an adjusted multiple-correlation coefficient of 0.947. Body width had the largest determinant coefficient, as well as the highest positive direct correlation with body weight. At the same time, high indirect effects with six other morphometric traits on L. maculatus body weight, through body width, were identified. Hence, body width could be a key factor that efficiently indicates significant effects on body weight in L. maculatus.

First genetic linkage map for the mud crab (Scylla paramamosain) constructed using microsatellite and AFLP markers.

The mud crab (Scylla paramamosain) is of economic importance for the fisheries and aquaculture industry in China. In this study, we constructed the first genetic linkage map for this species using microsatellite and amplified fragment length polymorphism (AFLP) markers. The map consisted of 65 linkage groups, including 34 triplets and 9 doublets. A total of 212 molecular markers were mapped, including 60 microsatellites and 152 AFLP markers. The linkage groups ranged from 7 to 102.5 cM and covered 2746.4 cM in length. The mean length was 42.3 cM per linkage group, and the mean spacing was 18.68 cM. The genome size was estimated to be 5539.62 cM, with 50% coverage by the present map. Moreover, we reported 5 transcriptome-derived polymorphic microsatellite markers and characterized their polymorphism in a first-generation family. This study will facilitate studies on high-density maps and molecular marker-assisted selection in S. paramamosain and related crustacean species.

Molecular cloning and gene expression analysis of cystatin C-like proteins in spinyhead croaker Collichthys lucidus.

Cystatins are natural tight-binding reversible inhibitors of cysteine proteases. In this study, a cDNA library was constructed from Collichthys lucidus using the SMART technique. A complete cDNA sequence with high identity to the conserved sequence of the cystatin C gene was cloned from the library using EST analysis and rapid amplification of cDNA ends (RACE), then subjected to further investigation. The full-length cDNA of cystatin C from C. lucidus (Clcys) was 699 bp long, including a 5'-terminal untranslated region (5'-UTR) of 52 bp, a 3'-UTR of 290 bp, and an open-reading frame of 357 bp. The gene encoded a polypeptide of 118 amino acids, constituting a predicted molecular weight of 12.875 kDa and a theoretical isoelectric point of 8.81. The amino acid sequence of Clcys possessed typical features of type II cystatins and had the highest identity with cystatin C of Pseudosciaena crocea (89%); therefore, it clustered with the cystatin C group in the UPGMA phylogenetic tree. Quantitative real-time reverse transcription analysis revealed that the highest expression was found in the kidney, followed by the liver, heart, and testis, with the lowest expression in muscle. Interestingly, Clcys had relatively low identity with cystatin C genes from other fish and mammals, and its expression pattern did not possess features of a housekeeping gene. Based on these findings, we suspect that the classification of cystatins in fish is somewhat confusing, and the identification of more cystatin gene sequences is needed before a definite conclusion can be drawn.

Spin-orbit coupling of light in asymmetric microcavities.

When spinning particles, such as electrons and photons, undergo spin-orbit coupling, they can acquire an extra phase in addition to the well-known dynamical phase. This extra phase is called the geometric phase (also known as the Berry phase), which plays an important role in a startling variety of physical contexts such as in photonics, condensed matter, high-energy and space physics. The geometric phase was originally discussed for a cyclically evolving physical system with an Abelian evolution, and was later generalized to non-cyclic and non-Abelian cases, which are the most interesting fundamental subjects in this area and indicate promising applications in various fields. Here, we enable optical spin-orbit coupling in asymmetric microcavities and experimentally observe a non-cyclic optical geometric phase acquired in a non-Abelian evolution. Our work is relevant to fundamental studies and implies promising applications by manipulating photons in on-chip quantum devices.

Characterization, molecular cloning, and expression analysis of Ecsit in the spinyhead croaker, Collichthys lucidus.

Evolutionarily conserved signaling intermediate in Toll pathways (Ecsit) is reported to play an essential role in innate immunity, embryogenesis, and assembly or stability of the mitochondrial complex I. In this study, the full-length cDNA of Ecsit was cloned from the spinyhead croaker Collichthys lucidus based on the expressed sequence tags from our cDNA library constructed using the SMART technique. The cDNA was 1669 bp long, including a 5'-terminal untranslated region (UTR) of 121 bp, a 3'-terminal UTR of 183 bp, and an open reading frame of 1365 bp encoding a 454-amino acid polypeptide. The estimated molecular weight of C. lucidus Ecsit (ClEcsit) was 52.50 kDa with an isoelectric point of 6.14, and contained a typical Ecsit domain that is conserved in other Ecsits. Multiple alignment of ClEcsit with other selected Ecsits suggested that some amino acid residues were highly conserved. Phylogenetic analysis indicated that ClEcsit was more similar to its identities in Sciaenidae and grouped with Ecsits from other Perciformes. Quantitative real-time reverse transcription PCR analysis revealed broad expression of ClEcsit and the transcript was strongly expressed in the gill and weakly expressed in other tissues.

Serum human epididymis protein 4 is associated with the treatment response of concurrent chemoradiotherapy and prognosis in patients with locally advanced non-small cell lung cancer.

AIM: To investigate the role of human epididymis protein 4 (HE4) in the diagnosis and prognosis of patients with locally advanced non-small cell lung cancer (LA-NSCLC) receiving concurrent chemoradiotherapy (CRT). METHODS: A total of 218 patients with LA-NSCLC were enrolled. All patients underwent CRT. The treatment response to CRT was evaluated. The prognosis analysis was performed using relapse-free survival (RFS) and overall survival [1]. RESULTS: Our data show that the serum HE4 can discriminate patients who respond well to CRT from those who respond poorly. Higher serum HE4 had dramatically increased risk of being non-responders to CRT. Serum HE4 level is also associated with prognosis of patients after CRT. Patients with high HE4 level had shorter RFS and OS compared to those with low HE4 level. CONCLUSION: Our data suggest that serum HE4 may be a useful prognostic biomarker for LA-NSCLC patients who underwent CRT.

Characterization of hemocyanin from the mud crab Scylla paramamosain and its expression analysis in different tissues, at various stages, and under Vibrio parahaemolyticus infection.

Hemocyanin is an important respiratory protein in many arthropod and mollusk species. Here, four cDNAs (SpHc1, SpHc2, SpHc3, and SpHc4), encoding distinct hemocyanin subunits from Scylla paramamosain were cloned using EST analyses and the rapid amplification of cDNA ends. The four full-length cDNA fragments (SpHc1-4) were 2281, 2002, 2184, and 2069 bp, respectively, and they encoded four putative proteins (570-676 amino acids) with a molecular mass of ~65.0-76.8 kDa. Quantitative real-time PCR analyses revealed that the four genes were mainly expressed in the hepatopancreas, testis, and hemocytes. SpHc mRNA expression during continuous developmental stages in zoeal phases (Z1, Z2, Z3, Z4, and Z5), megalopa, and juvenile crab I stages were also detected. The expression levels of SpHc3 and SpHc4 were higher than that of SpHc1 and SpHc2 during the first six stages, and they sharply declined during the juvenile stage. After infection with Vibrio parahaemolyticus, the temporal expression of both the four SpHc mRNAs in the megalopa stage rapidly declined during the first 3 h, followed by upregulation and peak expression at 12 h after the challenge. The expression levels of the four SpHc subunits were upregulated at 48 h after the challenge, and were then gradually downregulated. These findings suggest that hemocyanin may potentially be involved in the crab immune response, and that the role of the four subunits may differ in different tissues and during various developmental stages.

Discovery and characterization of a first set of polymorphic microsatellite markers in Siganus oramin.

Nine microsatellite DNA markers were developed and characterized for Siganus oramin by the 5'-anchored polymerase chain reaction technique. A total of 42 alleles were identified in 30 individuals, and the number of alleles per locus ranged from 3 to 7, with an average of 4.7. The observed and expected heterozygosity per locus ranged from 0.5333 to 1.0000 and from 0.5254 to 0.8474, respectively, with an average of 0.7422 and 0.6906, respectively. A significant deviation from the Hardy-Weinberg equilibrium was detected at one microsatellite locus after a Bonferroni's correction (P < 0.0056). No significant linkage disequilibrium was found between any of the pairs of the nine loci. The microsatellite loci developed in this study will improve our understanding of the genetic background of S. oramin.

Characterization and expression analysis of the prophenoloxidase activating factor from the mud crab Scylla paramamosain.

Prophenoloxidase activating factors (PPAFs) are a group of clip domain serine proteinases that can convert prophenoloxidase (pro-PO) to the active form of phenoloxidase (PO), causing melanization of pathogens. Here, two full-length PPAF cDNAs from Scylla paramamosain (SpPPAF1 and SpPPAF2) were cloned and characterized. The full-length SpPPAF1 cDNA was 1677 bp in length, including a 5'-untranslated region (UTR) of 52 bp, an open reading frame (ORF) of 1131 bp coding for a polypeptide of 376 amino acids, and a 3'-UTR of 494 bp. The full-length SpPPAF2 cDNA was 1808 bp in length, including a 5'-UTR of 88 bp, an ORF of 1125 bp coding for a polypeptide of 374 amino acids, and a 3'-UTR of 595 bp. The estimated molecular weight of SpPPAF1 and SpPPAF2 was 38.43 and 38.56 kDa with an isoelectric point of 7.54 and 7.14, respectively. Both SpPPAF1 and SpPPAF2 proteins consisted of a signal peptide, a characteristic structure of clip domain, and a carboxyl-terminal trypsin-like serine protease domain. Expression analysis by qRT-PCR showed that SpPPAF1 mRNA was mainly expressed in the gill, testis, and hemocytes, and SpPPAF2 mRNA was mainly expressed in hemocytes. In addition, SpPPAF1 and SpPPAF2 mRNA was expressed in a time-dependent manner after Vibrio parahaemolyticus challenge. The results showed that expression of both SpPPAF1 and SpPPAF2 was related to the bacterial challenge but the expression patterns differed. These findings suggest that SpPPAF is a serine proteinase and may be involved in the pro-PO activation pathway of the crab innate immune system.

Molecular identification of the genus Thryssa based on DNA barcoding.

DNA barcoding is an effective method for identifying species by analyzing one or a few short standardized DNA sequences. In this study, we examined the utility of mitochondrial cytochrome oxidase subunit I (COI) sequences as a DNA barcode for the identification of six species belonging to the genus Thryssa: T. dussumieri, T. hamiltonii, T. kammalensis, T. mystax, T. setirostris, and T. vitrirostris. We obtained an intraspecific distance of 0.000 for T. vitrirostris and T. hamiltonii, 0.006 for T. mystax, 0.002 for T. dussumieri, and 0.005 for T. kammalensis. The average intraspecific distance was 0.002, while the average interspecific distance was 0.137. Thus, the interspecific genetic distance was approximately 67-fold larger than the intraspecific genetic distance; the average genetic distance among species was greater than the minimum of 0.020 between species suggested elsewhere. The genetic distance between T. vitrirostris and T. mystax was 0.003. A maximum-likelihood phylogenetic tree constructed using best-fitting tree topology showed distinct clusters corresponding to the species (except for T. vitrirostris and T. mystax). The closest relationship was found between T. vitrirostris and T. mystax. These two species clustered together in the phylogenetic tree. This conclusion contradicts the evolutionary relationship based on morphological classification.

Molecular characterization of thioredoxin-1 and thioredoxin reductase activity in mud crab Scylla paramamosain.

The thioredoxin (Trx) system consists of thioredoxin reductase (TrxR), Trx, and nicotinamide adenine dinucleotide phosphate (NADPH). TrxR is an NADPH-dependent oxidoreductase. Trx is a ubiquitous small protein with a redox-active disulfide bridge that plays important regulatory roles in some vital metabolic reactions. In this study, a cDNA sequence (SpTrx1) showing high identity to the first Trx gene was isolated from a hepatopancreas cDNA library of the mud crab Scylla paramamosain. The full-length cDNA of SpTrx1 consisted of 672 bp and contained a complete open reading frame of 318 bp encoding a polypeptide of 105 amino acids. Quantitative real-time polymerase chain reaction analysis revealed that SpTrx1 expression was ubiquitous in various organs of S. paramamosain, including the gill, muscle, heart, hemolymph, testis, and hepatopancreas. SpTrx1 expression was upregulated significantly after Vibrio parahaemolyticus challenge: it obviously rose at 48 h and reached the highest level at 72 h. Furthermore, TrxR activity was detected in the gill, heart, muscle, hemolymph, and hepatopancreas. The relative TrxR activity in different tissues after V. parahaemolyticus injection had the same tendency in each tissue (P < 0.01) as SpTrx1 expression. The TrxR activity increased 2 h after injection, peaked at 8 h, slowly decreased from 12 to 24 h, and returned to normal levels at 48 h. The consistency of the expression between the Trx transcript and TrxR activity demonstrated that Trx was closely related to TrxR in the Trx system in S. paramamosain, suggesting that it may participate in the immune system of mud crabs.

Characteristics of growth traits and their effects on body weight of G1 individuals in the mud crab (Scylla paramamosain).

The mud crab (Scylla paramamosain) is considered a potentially important marine crab species for selective breeding. Here, we first examined sex ratio and differences in 16 growth traits between females and males in a G1 population of S. paramamosain, and we then analyzed the correlation between these growth traits and their effects on body weight (BW). Of these growth traits, nine were significantly different between sexes. In females, the correlation coefficients in all trait pairs ranged from 0.524 to 0.997. The traits carapace length (CL) and distance between lateral spine 2 (DLS2) significantly affected BW directly, with the path coefficients being 1.124 and -0.186, respectively. The determination coefficients of traits CL and DLS2 to BW were 1.263 and 0.035 with the total value being 0.951, indicating that the two traits were the key factors affecting BW. In males, the correlation coefficients in all trait pairs ranged from 0.881 to 0.999. The three traits body height (BH), fixed finger height of the claw (FFHC), and meropodite length of pereopod 2 (MLP2) significantly affected BW directly, with the path coefficients being 0.484, 0.300, and 0.225, respectively. The determination coefficients of traits BH, FFHC and MLP2 to BW were 0.234, 0.090 and 0.051, with the total value being 0.967, indicating that these three traits played a key role in affecting BW. Moreover, we constructed two best-fit linear regression equations, which were Y (BW) = 4.969 X1 (CL) - 0.758 X2 (DLS2) - 140.177 and Y (BW) = 3.806 X1 (BH) + 2.371 X2 (FFHC) + 1.725 X3 (MLP2) - 123.559 in females and males, respectively.

Correlation of growth-related traits and their effects on body weight of the mud crab (Scylla paramamosain).

In this study, we analyzed the correlation of 20 growth-related traits and their effects on body weight of Scylla paramamosain. The correlation coefficients in all trait pairs were significantly high, ranging from 0.551 to 0.999. Among 19 X-Y pairs, the correlation coefficient between traits X1 and Y was the highest, whereas that between X13 and Y was the lowest. Path analysis indicated that only two traits (X1 and X14) can significantly affect body weight (Y) directly, with the path coefficients being 0.800 and 0.198, respectively. The determination coefficients (di) of traits X1 and X14 to body weight were 0.640 and 0.039, respectively, and the total di was 0.965, indicating that both traits were the key factors affecting body weight. Moreover, traits X1 and X14 were confirmed to be significantly related to body weight. Finally, a best-fit linear regression equation was constructed as Y = 4.192X1 + 2.242X14 - 169.737.