| China is one of the countries with the most abundant livestock and poultry genetic resources in the world.Livestock and poultry genetic resources are not only the material basis for promoting the innovation of modern seed industry,but also an important strategic resource for maintaining biodiversity,national ecological security and agricultural security.Weishan Partridge duck is one of the four famous ducks in China.It is a high-quality local variety cultivated for a long time in Weishan Lake area,and there are few related basic studies.The purpose of this study was to study the growth and development and cecal microbial diversity of Weishan Partridge duck from 1 to 56 days of age,preliminarily reveal the early growth and development characteristics of Weishan Partridge duck,improve the relevant basic data of Weishan ducks,and provide basic data and scientific basis for the protection,development and utilization of Weishan duck varieties.In this study,200 one-day-old male and female Weishan Partridge ducks with the same batch of chicks and good health were selected.Blood was collected at 1,7,14,21,28,49 and 56 days of age for body weight and body size measurement.After slaughter,the organ index and slaughter performance were measured,and liver,spleen,leg muscle,chest muscle and duodenum tissue samples were collected for total RNA extraction to determine the relative expression of candidate genes.Cecal contents were collected for 16 S microbial diversity detection.The leg muscle and breast muscle were collected and stored in 4%paraformaldehyde solution for paraffin section to observe the physicochemical properties of muscle fibers.(1)With the increase of age,the average weight of ducks increased gradually.From 1 to 56 days of age,the weight of male and female ducks increased with the increase of age,and the weight of male ducks was higher than that of female ducks.The difference was significant at56 days of age(P < 0.05);each body size index increased with age,and the body size changes of male and female ducks were similar.Gender mainly affected beak length,neck length,body oblique length,chest depth,chest width and semi-diving length(P < 0.05).(2)At 49 days of age,the slaughter rate,eviscerated rate,semi-eviscerated rate and abdominal fat rate of male ducks were slightly lower than those of female ducks,and the differences were not significant.The breast muscle rate and leg muscle rate were slightly higher than those of female ducks,and the differences were not significant(P > 0.05).(3)With the increase of age,the content of growth hormone,thyroid hormone in the serum of male and female ducks gradually increased,and the content of insulin-like growth factor I showed a ’ M ’change trend.The ratio of T3 to T4 was 0.03 in 1-day-old female ducks,and the other days were stable at 0.02.The expression pattern of GH m RNA in breast muscle and leg muscle of male ducks was opposite,and the expression pattern of GH m RNA in breast muscle and leg muscle of female ducks was the same.The expression pattern of IGF-I m RNA in male duck breast muscle and leg muscle was the same,and the expression pattern in female duck breast muscle and leg muscle was opposite.(4)With the increase of age,the contents of IgG,IgA and IgM in the serum of male and female ducks increased gradually.(5)In male ducks,the expression pattern of IL-8 in serum was the same as that in liver and duodenum,while the expression pattern in spleen was opposite.The expression pattern of IL-18 in serum was the same as that in liver,while the expression pattern in spleen and duodenum was opposite.In female ducks,the expression pattern of IL-8 in serum was the same as that in spleen and duodenum.The expression pattern of IL-18 in serum was the same as that in liver,spleen and duodenum.(6)With the increase of age,the cross-sectional area of muscle fibers increased,and the density of muscle fibers decreased.The cross-sectional area of leg muscle fibers was larger than that of chest muscle,while the density was smaller than that of chest muscle.The expression patterns of Myf5,Myf6,Myo G,Myo D1 and MSTN in male and female ducks and non-tissues were different.The expression of Myf5,Myf6,Myo G,Myo D1 and MSTN showed significant differences before and after 14 days of age.(7)There are some differences in the microbial structure in the cecum of male and female ducks,but the overall evolution process is consistent.With the increase of age,the microbial species richness and evenness in the cecum gradually increased,and the microbial structure in the cecum of 1 day old was significantly different from that of other days.At the phylum level,the dominant bacteria at 1 day old were Proteobacteria and Firmicutes,while the dominant bacteria at other days old were Firmicutes and Bacteroides.At the genus level,the dominant flora at 1 day old was Escherichia-Shigella,belonging to Proteobacteria,while the dominant flora at other days old was Bacteroides,belonging to Bacteroidota.In summary,from 1 to 56 days of age,the body weight and body size indexes of Weishan Partridge duck increased with the increase of age.The body weight of male ducks was higher than that of female ducks,and the difference was significant at 56 days of age.Sex mainly affected body size indexes such as proboscis length,neck length,body slope length,breast depth,breast width and half-diving depth.With the increase of age,the immune function of Weishan Partridge duck gradually increased,showing a nonlinear change.The richness and evenness of microbial species in the cecum gradually increased.Proteobacteria and Firmicutes were the dominant phyla at 1 day of age,and Firmicutes and Bacteroidota were the dominant phyla at 7-49 days of age.With the increase of age,the breast muscle and leg muscle gradually developed,and the rapid growth period was from 28 to 49 days old.The expression trends of Myf5,Myf6,MyoG,MyoD1 and MSTN showed significant differences before and after 14 days old. |
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