High Growth Family Breeding And The Molecular Mechanism Research Of Yellow Catfish

Taking the evaluation of the growth performance of different lake populations and breeding high growth families as the main research objective,combining with the indexes of disease resistance and feed utilization,analysed breeding superiority of different combinations.Furtherly,explored regulation mechanism of nutrition,gene and their interaction on family growth of yellow catfish.Insulin-like growth factor I(IGF-I)is a key factor in the growth and development of endocrine system,which plays an important role in the growth and nutrition of animal,as well as nutrition regulation of growth.Studies have shown that through direct or indirect pathways nutrition regulates the expression of IGF-I,as well as the growth and development of fish.So we can breed families which utilize dietary nutrition effectively.Further explore its molecular mechanism.Then through dietary nutrition regulates the expression of IGF-I in vivo of yellow catfish,and adjusts the growth performance.These will be significant for breeding fast growth families of yellow catfishThe study includes six chapters:1 Selection of high growth parent populations and the comparison of growth performance of the offspring families of yellow catfishTo selection high growth patent populations and the offspring families of yellow catfish,in 2012,we established 49 full-sib families from five lakes'(Chaohu,C;Gehu,G;Hongzehu,H;Shijiuhu,S;Taihu,T)yellow catfish parents,including 17 interpopulation breeding combinations and 5 intrapopulation breeding combinations.Offspring of the 49 families were cultured separately and mixed after implanting electronic fluorescent tags.Body weight(g)and survival rate of these families' juvenile were measured after 120 days and 460 days.Growth performance of different populations was evaluated by analyzing the least squares mean(LSM)and heterosis for families' body weight in yellow catfish.The results showed that the variation coefficient of body weight was 0.25-0.66.The LSM body weight of the G,T,S offspring were higher than average by 2.98%,2.99%and 0.98%respectively,indicating these three populaitons could be used as high quality cultivars'parents.The growth performance analysis showed the average LSM of interpopulation breeding combinations(105.48 g)was 3.58%higher than that of intrapopulation breeding combinations(101.83 g).The highest LSM occurred in the breeding combinations G(?)×S(?),G(?)×C(?),S(?)×T(?),and they were 125.55 g,121.76 g,120.08 g respectively.Heterosis analysis showed that,there were significant superiority between mid and remote-parents heterosis in the breeding combinations G(?)× S(?),G(?)× C(?),S(?)×T(?),mid-parent heterosis were 29.89%,22.36%and 20.99%respectively,remote-parent heterosis were 15.77%,11.50%and 4.62%respectively.Our study's results are benefit to improve the accuracy of genetic selection for growth performance of yellow catfish,they will be the foundation for breeding of improved variety.2 Comparison of growth,body composition and digestive enzyme activities on five family groups of yellow catfishTo compare growth,body composition and digestive enzyme activities on different family groups of juvenile yellow catfish,we established 5 breeding family groups:intrapopulation breeding groups ?(G ? × G ?),?(S ? × S ?),?(T ? × T ?)and interpopulation breeding groups ?(G ? ×S ?),?(S ?×T ?)respectively.The parents were wild yellow catfish that come from Ge hu(G),Shijiu hu(S)and Tai hu(T)lakes.When juvenile yellow catfish were on 70th days,we chose 600 yellow catfish individuals from each family group and set up 3 parallel groups.All test fish were fed to the same commercial feed.The culture experiment lasted 60 days.The body weight,Absolute growth rate of body weight(AGRW),Feed conversion ratio(FCR),Survival rate(SR)and gastrointestinal digestive enzyme activities data would be collected at 60th days.The results showed that:there were significant differences of AGRW,WGR,FCR and SR in different family groups(P<0.05).AGRW and WGR of family group ? were highest,with 0.126 ±0.005,316.11±15.67 respectively,which was significantly different with that of family group ?.The protease activity of stomach and intestine of family group ? were significantly higher than other family groups(P<0.05).There were not significant difference on amylase and lipase among the different family groups(P>0.05).To conclude,family group ?(G?×S?)utilize dietary protein better than other family groups.The feed utilization and growth rate are promoted.So ?(G?×S?)is a breeding conmbinaiton with breeding superiority.3 A comparative study of immune parameters on different family groups of yellow catfish by injecting Aeromonas hydrophilaIn order to explored the immunity performance of different family groups,five yellow catfish family groups:?(G ? × G ?),?(S ? × S ?),?(T ? × T ?),?(G ? × S ?)and ?(S? × T ?)were selected as research items.300 juveniles per family group of 130 days were injected Aeromonas hydrophila.At 0 h,6 h,24 h and 48 h points after injection,juveniles were observation and sampled for determined the Cumulative mortality rate(CM)and the biochemical parameters of serum and liver,containing Total protein(TP),Lactic acid(LA),Alanine aminotransferase(ALT),Aspartate aminotransferase(AST),Alkaline phosphatase(AKP)of serum and Superoxide dismutase(SOD),Malondialdehyde(MDA)of liver.The results showed that,all biochemical parameters except AKP were significantly different among the five groups after injection(P<0.05).At 48 hour-point after injection,CM in the order from high to low is family group ?>?>?>?>?.The serum TP level peaked at 24 hour-point after injection,and then gradually decreased.At 48 hour-point,TP levels of family group ? and ? were significantly higher than the others(P<0.05).After injection,the serum LA index of each group showed a trend of increasing first and then decreasing.At 48 hour-point,the serum LA of group ? and ? were significantly lower than others.The serum transaminase levels increased sharply after injection.At 24 hour-point,the ALT level of group ? and ? recovered to 0 h level.The liver SOD level peaked at 24 hour-point after injection.At 48 hour-point,the SOD of group ? was the highest among all test groups(P<0.05).At 6 hour-point,the liver MDA of group ? was significantly lower than others(P<0.05).At 48 hour-point,MDA of group ? was significantly higher than group ?,? and?(P<0.05).The results indecate that the family groups of yellow catfish have significant differences in immune levels.Family group ?(G ? × G?)in CM,TP,LA,ALT and MDA indicators shows strong anti-stress,nonspecific immunity,liver antioxidant ability,and shows resistance advantage in anti-Aeromonas hydrophila.4 Insulin-like growth factor-? of yellow catfish:cDNA characterization,tissue distribution and expressions in response to feeding regimesThe full length cDNA coding IGF-? was cloned from the liver of yellow catfish,and the tissue distribution was also analyzed.Furthermore,the effects of starvation(3 weeks)and subsequent re-feeding(3 weeks)on the compensatory growth performance and hepatic IGF-? mRNA expressions were also investigated.The cDNA obtained covered 884 bp including an open reading frame of 480 bp encoding 159 amino acids.It is composed of a signal peptide(41 amino acids(AAs)),a mature peptide comprising the B,C,A,and D domains(71 AAs)and E domain of 47 AAs.Sequence alignment and phylogenetic analysis revealed a high degree of conservation(71%-87%)among most Siluriformes and some relative species in GenBank.The highest IGF-I expression was observed in liver followed by brain,whereas relatively low expression were detected in muscle and stomach.Both body weight and length of catfish increased significantly with continuous feeding(P<0.05),while condition factor showed little difference(P>0.05).Body weight,body length,condition factor and hepatic IGF-I expression decreased remarkably with starvation(P<0.05),but increased significantly after re-feeding(P<0.05).The results indicated that the IGF-I gene of yellow catfish shared a high similarity with that of the other relative vertebrates,and its expressions was positively correlated with feed intakes.5 IGF-I DNA clone and SNPs detection of yellow catfishWe designed primer on basis of IGF-I cDNA,separating,sequencing and splicing DNA sequence of yellow catfish by polymerase chain reaction(PCR),then obtained sequence of IGF-I DNA.Its length is 5536 bp,including 4 extrons and 3 introns.The lengths of 4 extrons are 33 bp,351 bp,36 bp and 144 bp.The lengths of 3 introns are 1174 bp,1464 bp,2064 bp respectively.We operated PCR amplification and sequencing analysis to DNA pool of 40 yellow catfish and 20 individual,and found seven SNPs.They are g.2143G>C,g.2539A>G,g.2711A>G,g.3187A>G,g.4095A>G,g.4305C>A,g.4343C>T respectively.The g.2143G>C,g.2539A>G,g.2711A>G are located in the second intron and the g.3187A>G,g.4095A>G,g.4305C>A,g.4343C>T are located in the third intron.The 7 SNPs are all bi-allelic polymorphisms,including 5 transition and 2 transversion.6 Effects of families and feed protein contents on growth performance and hepatic expression of IGF-? mRNA of juvenile yellow catfishThis study was conducted to investigate the effects of families and feed protein contents in growth performance and hepatic expression IGF-I of juvenile yellow catfish.For each experimental family group(G(?)× S(?),S(?)×S(?))(Gehu,G;Shijiuhu,S),300 juveniles were randomly allocated to 2 groups with 3 replicates per group and 50 juveniles per replicate,and cultured with the experimental diet with protein contents 37%(P37)or protein contents 40%(P40)for 60 d.The results showed as follows:the final weight,weight gain,specific growth rate and the hepatic IGF-I expression were significantly affected by families and dietary protein contents(P<0.05).There was not interaction between the two factors in these indexes.P40/(G(?)× S(?))group obtained the maximum final weight,weight gain rate and the highest hepatic IGF-I expression level.It is concluded that juvenile yellow catfish can achieve better breeding effect through family breeding and feed protein nutrition regulation.(G(?)× S(?))in high protein diet feeding gains the best growth performance.