Simulation of the distribution,growth,and survival rate of chub mackerel larvae and juveniles in the East China Sea

In the East China Sea(ECS),chub mackerel Scomber japonicus constitutes an important coastal-pelagic fishery resource that is mainly exploited by Chinese,Japanese,and Korean light-purse seine fisheries.Because the early life history of chub mackerel plays a significant role in its recruitment,we developed an individual-based model to study the distribution,growth,and survival rate of chub mackerel larvae and juveniles in the ECS to improve our understanding of the chub mackerel population structure and recruitment.Our results show that as body length rapidly increases,the swimming capacity of chub mackerel larvae and juveniles improves quickly,and their spatial distribution depends more on their habitat conditions than the ocean currents.Correspondingly,the juveniles from the central and southern ECS spawning ground are scarcely recruited into the Japan/East Sea(JES)or the western Pacific Ocean,but a significant proportion of juveniles from the northern ECS spawning ground still enter the JES and there are exchanges between the stocks in the ECS and JES.Thus,it seems more reasonable to assess and manage the chub mackerels in the ECS and JES as a stock.The water temperature and ocean primary production in the ECS are two important factors influencing the chub mackerel habitat conditions and their spatial and temporal distribution are significantly different as the spawning time changes.Therefore,the spawning time and location play an important role in the growth and survival rate of the larvae and juveniles.Generally,when chub mackerel spawns at the southern ECS spawning ground in March,the larva and juvenile growth and survival rate is relatively high;as spawning time moves forward,higher growth and survival rates would be expected for the chub mackerel spawned coastward or northward.For specific spawning sites,early or delayed spawning will reduce the survival rate.

Dietary calcium requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age

Background:The current calcium(Ca)recommendation for broilers is primarily based on studies conducted more than 30 years ago with birds of markedly different productive potentials from those which exist today.And the response indicators in these studies are mainly growth performance and bone ash percentage.Therefore,the present study was carried out to investigate the effect of dietary Ca level on growth performance,serum parameters,bone characteristics and Ca metabolism-related gene expressions,so as to estimate dietary Ca requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age.Methods:A total of 4201-day-old Arbor Acres male broilers were randomly assigned to 1 of 7 treatments with 6 replicates(10 birds per cage)and fed the corn-soybean meal diets containing 0.60%,0.70%,0.80%,0.90%,1.00%,1.10%or 1.20%Ca for 21 days.Each diet contained the constant non-phytate phosphorus content of about 0.39%.Results:The average daily gain decreased linearly(P<0.001)as dietary Ca level increased.The serum and tibia alkaline phosphatase(ALP)activities,tibia bone mineral density(BMD),middle toe BMD,tibia ash percentage,tibia breaking strength,and tibia ALP protein expression level were affected(P<0.05)by dietary Ca level,and showed significant quadratic responses(P<0.02)to dietary Ca levels.The estimates of dietary Ca requirements were 0.80 to 1.00%based on the best fitted broken-line or quadratic models(P<0.03)of the above serum and bone parameters,respectively.Conclusions:The results from the present study indicate that the Ca requirements would be about 0.60%to obtain the best growth rate,and 1.00%to meet all of the Ca metabolisms and bone development of broilers fed a conventional corn-soybean meal diet from 1 to 21 days of age.

WheatCENet:A Database for Comparative Co-expression Network Analysis of Allohexaploid Wheat and Its Progenitors

Genetic and epigenetic changes after polyploidization events could result in variable gene expression and modified regulatory networks.Here,using large-scale transcriptome data,we constructed co-expression networks for diploid,tetraploid,and hexaploid wheat species,and built a platform for comparing co-expression networks of allohexaploid wheat and its progenitors,named WheatCENet.WheatCENet is a platform for searching and comparing specific functional coexpression networks,as well as identifying the related functions of the genes clustered therein.Functional annotations like pathways,gene families,protein-protein interactions,microRNAs(miRNAs),and several lines of epigenome data are integrated into this platform,and Gene Ontology(GO)annotation,gene set enrichment analysis(GSEA),motif identification,and other useful tools are also included.Using WheatCENet,we found that the network of WHEAT ABERRANT PANICLE ORGANIZATION I(WAPOI)has more co-expressed genes related to spike development in hexaploid wheat than its progenitors.We also found a novel motif of CCWWWWWWGG(CArG)specifically in the promoter region of WAPO-Al,suggesting that neofunctionalization of the WAPO-AI gene affects spikelet development in hexaploid wheat.WheatCENet is useful for investigating co-expression networks and conducting other analyses,and thus facilitates comparative and functional genomic studies in wheat.

Metabolic utilization of intravenously injected iron from different iron sources in target tissues of broiler chickens

No information is available regarding the utilization of iron (Fe) from different Fe sources at a targettissue level. To detect differences in Fe metabolic utilization among Fe sources, the effect of intravenouslyinjected Fe on growth performance, hematological indices, tissue Fe concentrations and Fe-containingenzyme activities and gene expressions of Fe-containing enzymes or protein in broilers was investigated.On d 22 post-hatching, a total of 432 male chickens were randomly allotted to 1 of 9 treatments ina completely randomized design. Chickens were injected with either a 0.9% (wt/vol) NaCl solution(control) or a 0.9% NaCl solution supplemented with Fe sulphate or 1 of 3 organic Fe sources. The 3organic Fe sources were Fe chelates with weak (Fe-MetW), moderate (Fe-ProtM) or extremely strong (Fe-ProtES) chelation strength. The 2 Fe dosages were calculated according to the Fe absorbabilities of 10%and 20% every 2 d for a duration of 20 d. Iron injection did not affect (P > 0.05) ADFI, ADG or FCR duringeither 1 to 10 d or 11 to 20 d after injections. Hematocrit and Fe concentrations in the liver and kidney ond 10 after Fe injections, and Fe concentrations in the liver or pancreas and ferritin heavy-chain (FTH1)protein expression level in the liver or spleen on d 20 after Fe injections increased (P≤0.05) as injectedFe dosages increased. When the injected Fe level was high at 20% Fe absorbability, the chickens injectedwith Fe-ProtES had lower (P < 0.001) liver or kidney Fe concentrations and spleen FTH1 protein levelsthan those injected with Fe-MetW or Fe-ProtM on d 20 after injections. And they had lower (P < 0.05)liver cytochrome C oxidase mRNA levels on d 20 after injections than those injected with Fe-MetW or Fesulphate. The results from this study indicate that intravenously injected Fe from Fe-ProtES was the least utilizable and functioned in the sensitive target tissue less effectively than Fe from Fe sulfate, Fe-MetW or Fe-ProtM.