| The purpose of this research was to study the early growth and development pattern of Yili geese and the difference of muscle fiber tissue structure in different growth periods,and to apply RNA-Seq technology to analyze the leg muscle tissue of Yili geese in different growth stages,to initially screen the candidate genes related to the regulation of muscle growth and development of Yili geese,and to explore the genetic mechanism of early growth and development of Yili geese.150 0 day old Yili geese with good health condition were selected in the beginning of the experiment.Half of them were male and half of them were female.The experiment period was 10 weeks.During the experiment period,the weight changes of male and female Yili geese were measured at each week of age,and the muscle tissues of the legs of Yili geese at different weeks of age were collected for muscle fiber histological observation and transcriptome sequencing.The results from experiment showed that:(1)The growth curves of male and female Yili geese are nearly “S” type,basically match with the general law of poultry growth and development.Female Yili geese reach the growth peak at age of 4 weeks,male Yili geese reach the growth peak at age of 5 weeks,and then the growth rate started to decrease gradually.Both male and female Yili geese gain weight slow at age of 8 weeks.(2)Based on the fitting analysis to male and female Yili geese aged 0-10 weeks old with Logistic,Gompertz and Bertalanffy models,the Gompertz model was having the best fitting result,and the inflection point ages of male and female geese under this model were 4.032 and 3.504 weeks.The inflection point weights of male and female geese were 1475.762 g and 1200.772 g,and the fitting estimates from Gompertz model were closer to the actual observed values of male and female Yili geese.(3)The results of the study on the histological characteristics of leg muscles showed that the muscle fiber density of male geese aged 4 weeks were significantly lower than that of female geese(P<0.01),the diameter and cross-sectional area of muscle fibers at age 6,8 and 10 weeks were significantly higher than female geese(P<0.01),myofiber density decreased when age increased,and were significantly higher than in females when males were at 4 and 6 weeks(P<0.01).At age 10 weeks the myofiber density for male geese were significantly lower than female geese(P<0.01).The muscle fiber diameter and cross-sectional area of male geese grew fastest from age 4 to 6 weeks,and the muscle fiber density decreased rapidly at age4 to 8 weeks.While the muscle fiber diameter and cross-sectional area of female geese grew fastest at age 2to 6 weeks,and the density decreased rapidly after age 6 weeks,and the muscle fiber growth rate gradually decreased.(4)The results of leg muscle m RNA expression profiling indicated that a total of 502,065,268 valid data,75.30 Gb data volume,were obtained from12 of Yili geese samples.Analysis of differential expressed genes between sample groups revealed 1700,1583 and 221 differential expressed genes in the three comparison groups of 4 weeks vs.2 weeks(T4 vs.T2),8 weeks vs.2 weeks(T8 vs.T2),and 8 weeks vs.4weeks(T8 vs.T4),respectively.GO annotation and KEGG enrichment analysis of differential expressed genes revealed that differential expressed genes were significantly enriched in GO terms including organelle organization,cytoskeletal protein binding,cation transport,myosin complex,and actin cytoskeleton.Among the significantly enriched signaling pathways,five pathways significantly associated with growth and development were identified: focal adhesion,ECM-receptor interaction,tight junction,TGF-β signaling pathway and MAPK signaling pathway.A total of 38 differential genes were included in those five pathways.It is hypothesized that these pathways and the DEGs in the pathways play an important regulatory role in the early growth and development of Yili geese.In conclusion,this research was conducted fitting analyze of weight data of Yili geese to study the growth and development pattern of Yili geese and provide the reference basis for the efficient production and scientific feeding management of Yili geese.Then according to the observation of muscle fiber histomorphology and muscle transcriptome sequencing analysis to screening the candidate genes related to the regulation of growth and development of Yili geese initially,and to provide a theoretical basis for revealing the genetic mechanism of muscle growth and development of Yili geese. |
