Effects Of Stocking Density And Population Size On Broiler And Analysis Of Liver Of Proteomics Broilers Of Different Population Sizes

The broiler stocking density is deeply concerned by the breeding industry.The stocking density not only affects the utilization rate of breeding facilities,but also directly affects the growth,health and welfare of broilers.It is one of the important process parameters for large-scale broiler production.Various factors affect the appropriate parameters of broiler stocking density,including:breed,sex,feeding method,group size,environmental conditions,etc.The welfare status of poultry is determined by the interaction between groups and the activity space.The reduction of activity space and the reduction of activity frequency may cause aggressive behavior and stress response of broilers,which makes broiler welfare status decline.At present,the research on the effects of stocking density and group size on broiler production and health status is mostly focused on the study of apparent performance,and there are few studies on the mechanism and interaction between the two.The liver can be used as a target organ for studying the metabolism of substances and an important organ involved in the immune and metabolism of poultry.Various physiological and biochemical reactions such as protein,fat and carbohydrate metabolism in the body require the participation of the liver.The overall study of the liver’s expression of all proteins is of positive significance for understanding its metabolic changes.This experiment uses a completely randomized trial design to study the effects of stocking density and group size on broiler growth,immunity,bone development,and intestinal microecology,and uses omics technology to explore the mechanism of group size on broiler liver.Adopt reasonable stocking density,increase poultry production,and improve animal welfare to provide a theoretical basis.A total of 480 healthy Ross 308 male broilers with similar body weights at 21 days of age in the same batch were selected.They were designed using a 2*2 factor and randomly divided into 4 treatments,each with 6 replicates.The small-scale low-density group repeated 7 chickens each,the small-scale high-density group repeated 9 chickens each,the large-scale low-density group repeated 28 chickens each,and the large-scale high-density group repeated 36 chickens each.The cage area is divided into two types:large and small:0.49 m2(0.70m*0.70m)and 1.96 m2(0.70m*0.70m*4),and high and low density:18/m2,14/m2.Adopting three layers of superimposed cages,according to NY/T 2003 to prepare diets,feeding in the form of powder,free to eat and drink water,the test period is 21d.Clean the house regularly every day,observe the flock,and record the temperature and humidity of the house.The test results are as follows:1:Effect of stocking density and group size on broiler performanceThe measurement results show that the survival rate is significantly affected by the group relationship(P<0.05),and the survival rate of the small group is significantly higher than that of the large group(P<0.05);the average daily feed intake is significantly affected by the interaction of stocking density and group relationship(P<0.05),and the daily average feed intake of the large-scale high-density group is significantly higher than that of the other groups(P<0.05),but the stocking density and group size have no significant effects on the broiler feed ratio and final weight.2:The effect of stocking density and group size on the immune function of broilersThe results of serum immune factors showed that IgA,IgG,IgM is not affected by group size and stocking density,but IgA is significantly affected by the interaction of group size and stocking density(P<0.01),and IgG and IgM are significantly affected by the interaction of stocking density and group relationship(P<0.05).Serum antioxidant index results show that the total antioxidant capacity is significantly affected by the group size(P<0.01).Under the same stocking density,the total antioxidant capacity of the large group is significantly higher than that of the small group.The contents of catalase,superoxide dismutase and malondialdehyde are not affected by the stocking density and group size and their interaction.3:Effect of stocking density and group size on bone development of broilersThe results of serum bone development related indicators showed that blood phosphorus was significantly affected by the interaction of stocking density and group relationship(P<0.05),and the content of blood phosphorus in the large-scale low-density group was significantly higher than that of other groups.Alkaline phosphatase is very significantly affected by the interaction of stocking density and group relationship(P<0.01),and the activity of the large-scale high-density group is significantly lower than that of other groups(P<0.01).Tibial calcium content was significantly affected by stocking density(P<0.01),phosphorus content was significantly affected by stocking density(P<0.05),and calcium content was significantly affected by stocking density and group size interaction(P<0.05).Tibia length,fresh weight,bone density and mineral salt content are not affected by group size and stocking density.Femur fresh weight was significantly affected by the interaction of stocking density and group size(P<0.05);bone mineral salt and bone density were significantly affected by the stocking density(P<0.01),affected by the interaction of stocking density and group size The effect is extremely significant(P<0.01);the difference of the femoral coarse ash content by the stocking density is extremely significant(P<0.01),and the group size is significantly different(P<0.05),but the interaction between the two is not significant.Humeral bone minerals were significantly affected by stocking density and group size(P<0.05),and the interaction between the two was significantly different(P<0.05).Crude ash content and phosphorus content were significantly affected by stocking density(P<0.01),and calcium content was significantly affected by stocking density(P<0.05),but not affected by the interaction between the two.4:Effects of stocking density and group size on the micro-ecology of broiler intestinesThe ileum counts the species abundance of each sample at the taxonomic level.The main dominant bacterial group in the four groups is Lactobacillus.TEST1(large-scale high-density group)was 98.53%,TEST3(large-scale low-density group)was 97.66%,TEST4 was(small-scale high-density group)96.42%,and TEST6(small-scale high-density group)was 99.60%.The ileal chyme samples of four different groups were analyzed for the significance of the difference between the dominant genus and species levels.The results showed that there was no significant difference in the composition of intestinal microbes between the four groups at the genus and species levels Kruskal-Wallis H test,P>0.05).The sobs index TEST1(large-scale high-density group)and TEST3(large-scale low-density group)detected in the cecum sample were significantly different(0.01<P≤0.05),and the large+low group was significantly higher than the large+high group;the sample detected The Sobs index TEST3(large-scale low-density group)and TEST6(small-scale low-density group)were significantly different(0.01<P≤0.05),and TEST3 was significantly higher than TEST6(P<0.05).TEST3(large-scale low-density group)has the highest diversity of intestinal flora.Sobs,Ace index,and Simpson index are significantly affected by the interaction of stocking density and group size(0.01<P≤0.05),indicating that both stocking density and group size affect the microbial diversity of cecum in broilers.At the phylum level,Proteobacteria phylum groups were significantly different(Kruskal-Wallis H test,P<0.05),P=0.04,other bacterial groups were not significantly different,but small-scale low-density group and small-scale high-density group Bacteroides abundance increased.At the genus level,there were significant differences between Parabacteroides group(Kruskal-Wallis H test,P<0.05),P=0.039.5:Proteomic analysis of livers of broiler chickens of different population sizesThe test results showed that the number of proteomics identified in the broiler liver was 3123,and the number of proteins containing quantitative information was 2923.Principal component analysis showed that there were differences in protein between groups.Comparing the treatment group with the control group,there were a total of 284 differential proteins,of which 157 proteins were up-regulated and 127 proteins were down-regulated.Inconsistent proteins may be key proteins that differ in expression at different population sizes.Comparing the differentially expressed proteins in the liver,ACSL,CPT-I,GST,APs,XDH,PMP70,and HPCL2 were the key proteins for the differences.These proteins can be used as candidate proteins to study the differences in liver metabolism of broilers of different population sizes.It can be seen that under different population-scale treatment conditions,liver tissue of broiler chickens may be more likely to cause damage and result in changes in functional protein expression under small-scale treatment.Sum up:1:Under this set of experimental conditions,it was found that the feeding density had no significant effect on the growth performance of broilers(feed ratio and terminal weight),but the effect on the bone development indicators of broilers was significantly or significantly different.low density:It is easier for the healthy development of bones under feeding conditions.2:The group size has a significant effect on the survival rate of broilers,and the survival rate of the small group is significantly higher than that of the large group.3:There is a certain interaction between the feeding density and the group size on broiler immunity and intestinal microecology.Under the current test conditions,the immune capacity of the large-scale low-density group and the abundance and diversity of intestinal microflora are the best.4:Through preliminary analysis of liver tissue proteomics of different groups of broiler chickens,it is concluded that ACSL,CPT-I,GST,APs,XDH,PMP70,HPCL2 are the key proteins of the difference between the two,which can be used as liver metabolism of different groups of broilers Candidate proteins for differences in pathways and signal transduction pathways.