Analysis Of Nutrient Composition And Gene Expression Related To Growth Of Hybridization Between Larimichthys Polyactis ♀ And L.Corcea ♂

In this experiment,the nutrient composition and the growth-related gene expression analysis of the Larimichthys polyactis,L.crocea and their hybrid(L.polyactis ♀× L.crocea♂)were carried out.The main tasks were as follows:The muscle nutrients of the hybrid and their parents were compared and analyzed.The water content of the hybrid was 72.95%,lower than the moisture content of the parents(L.polyactis: 73.67%,L.crocea: 74.06%),indicating that the hybrid progeny had low moisture characteristics.The crude protein content in muscle of hybrid progeny was16.94%,significantly higher than those of the parents(L.polyactis: 15.98%,L.crocea:16.07%).The crude fat content(4.95%)was significantly smaller than that of the L.crocea(5.39%),and significantly larger than that of the L.polyactis(4.64%).The total amino acid content of the hybrid progeny(74.71%)was not significantly different from that of the L.crocea(71.44%),but significantly higher than that of the L.polyactis(71.11%);the total content of essential amino acids(30.76%)was significantly higher than that of the L.crocea(29.24%)and L.polyactis(29.28%).The results of nutritional value evaluation showed that the nutritional value of the three fish was hybrid > L.crocea > L.polyactis.The total amount of taste amino acids in the hybrid was as high as 28.86%,slightly higher than that of the L.crocea(27.69%),which was significantly higher than that of the L.polyactis(27.37%).The SFA content of the hybrid progeny was higher than those of the parents,while the MUFA and PUFA content were between the contents of the two parents;the PUFA/SFA(57.46%)of the hybrid progeny was also between the contents of the two parents(L.crocea: 56.54%,L.polyactis: 63.52%),both of which were higher than the recommended value of fatty acid composition(40%).The IGF-1 expression levels of the three tissues in the three kinds of 15 months old fish were: liver>brain>muscle,and the expression level of the gene in female individuals was generally higher than that in males.The expression levels of IGF-1 gene in the same tissue of three fish species were also significantly different.For the three fish,the order ofthe IGF-1 gene expression levels in liver and brain from high to low was L.polyactis >hybrids > L.crocea.The gene expression in muscle of the three kinds of female fish was: L.polyactis > hybrid > L.crocea,but the gene expression in muscles of the three kinds of male fish is L.polyactis > L.crocea > hybrids.The GH expression levels of the three tissues in the three kinds of 15 months old fish were: brain>muscle>liver,and the expression level of the gene in female individuals was generally higher than that in males.The expression levels of GH gene in the same tissue of the three fish species were also significantly different.For the three kinds of fish,the order of the IGF-1 gene expression levels in Muscle and brain from high to low was L.crocea> hybrids> L.polyactis.The gene expression in liver of the three kinds of female fish is L.crocea> L.polyactis>hybrids,but the male is L.crocea> hybrids> L.polyactis.The GHR1 expression levels of the three tissues in the three kinds of 15 months old fish were: liver> muscle > brain.Additionally,the expression level of the GHR1 gene in male individuals was generally higher than that in females.The expression levels of GHR1 gene in the same tissue of three species of fish were significantly different,and the expression levels of GHR1 gene in the three tissues of male and female individuals showed a trend as follows: L.crocea>hybrids > L.polyactis.