Comparative Analysis Of Differences In Growth,Disease Resistance And Meat Quality Of Different Geographical Populations Of Mylopharyngodon Piceus

Black carp（Mylopharyngodon piceus）is an important freshwater fish in our country.With the changes in the ecological environment and the transformation of breeding methods,the regional distribution of wild populations of black carp has changed greatly,and the number of wild populations of black carp is also decreasing.In addition,in the production process of black carp fry,the production units did not pay attention to the management of germplasm resources,which also resulted in the slow growth rate of black carp germplasm resources,the decline of disease resistance and the decline of meat quality and nutritional value.In order to ensure the healthy and stable development of black carp breeding industry,it is urgent to carry out breeding and genetic improvement of black carp,and cultivate varieties with good growth performance,excellent stress resistance and high nutritional value of meat quality.In this paper,the growth performance,disease resistance and meat nutritional value of three different geographical populations of black carp in the Yangtze River system were compared,and the populations with fast growth,strong disease resistance and high meat nutritional value were selected,so as to provide theoretical basis for the evaluation and utilization of black carp Germplasm Resources.The main contents are as follows:1.By evaluating the growth performance of different groups of black carp,the black carp from Xiangjiang in Hunan,Shishou in Hubei,and Hanjiang in Jiangsu used PIT markers and the same pond polyculture method in cages to compare the growth differences of three different geographic groups.One-way analysis of variance,correlation analysis,multiple comparisons were accustomed analyze the enlargement variations and also the correlation between traits of black carps within the same population.The results showed that among the 3 teams,the Hanjiang cluster grew well in terms of weight gain rate,rate of growth,growth index,etc.The Xiangjiang population has lower body weight gain rate and growth index,indicating that the Xiangjiang population grows slowly.The difference in weight gain between Shishou population and Hanjiang population was not significant,but there was an oversized degree of separate growth in body breadth and height.The correlation coefficients of assorted phenotypical traits and body mass are very vital（P<0.01）.Comprehensive studies have shown that the Hanjiang population has the best growth performance and can be used as the main target for selection of improved varieties.The results of the study will offer a basis for the breeding of elite black carp populations.2.In order to explore the disease resistance of different groups to Aeromonas hydrophila,the black carp of different geographical groups in the Yangtze River was infected with Aeromonas hydrophila,and the test water temperature was 27±1℃.First,30 black carps were infected through preliminary experiments,and the LC₅₀was calculated as 5.0ⅹ10⁷cfu/m L by referring to the Reed-Muench method.Then the black carps of the three groups were artificially infected,the additive mortality of every cluster was counted,and also the malady resistance performance of the 3 teams was compared.The results showed that the additive mortality of Hanjiang population was26.7%,that of Shishou population was 46.6%,and that of Xiangjiang population was63.3%.The analysis of variance showed that the three populations of black carp had differences in disease resistance to Aeromonas hydrophila.The order of disease resistance of the three populations of black carp was Hanjiang population>Shishou population>Xiangjiang population,and Shishou population and Xiangjiang population were different.Not obvious,the Hanjiang population is significantly different from the Xiangjiang and Shishou populations（P<0.05）.3.In order to explore the variations in muscle biological process quality of various geographic teams of black carp,the national commonplace organic chemistry technique was wont to confirm the content of standard nutrients,amino acids and fatty acids in black carp muscle,and also the biological process quality was evaluated in keeping with FAO/WHO standards.The results of the study showed that the mass fractions of water in conventional muscle nutrition of the three groups of black carp were 81.08%-82.2%,crude protein 16.86%-17.94%,crude fat 0.46%-0.52%,and crude ash content1.26%-1.34%.There is no vital distinction between them.sixteen amino acids were detected within the muscles of the 3 teams of black carp,together with seven essential amino acids.Essential amino acids accounted for thirty-nine.26%-40.25%of the full organic compound content,and savory amino acids were 38.55%-39.28%.In terms of carboxylic acid composition and content,eighteen fatty acids were detected in Hanjiang and Shishou populations,together with nine saturated fatty acids,three monounsaturated fatty acids,and six unsaturated fatty acids,all over Xiangjiang.The three black carp groups all contained high levels of DHA+EPA,which accounted for10.63%of the total fatty acids.Comprehensive research results show that the black carps of the three groups all contain high protein,richer amino acids and fatty acids,and high-quality aquatic products with high nutritional value.Among them,the Hanjiang group is more excellent.