| Fermentation feeds utilize the metabolism of probiotic strains and controlled fermentation conditions to the produce feeds that are rich in probiotic activity and their functional metabolites.The development of fermented feeds provides a feasible alternative to the use of antibiotics in animal husbandry.In this experiment,probiotic strains preserved in the laboratory were compounded into fermentation agents according to requirements.and poultry compound feed was fermented in a solid state.Fermentation conditions were optimized by comparing the pH,acid soluble protein/crude protein,and antibacterial activity of fermented feed under different conditions.Layers were fed fermented feed and the effects on the production status and egg quality improvement were observed.Layer intestinal flora diversity were also analyzed using high-throughput sequencing.The test results are as follows:1.The fermentation quality of feed is affected by the fermentation mode and technological conditions.In this experiment,SPSS software was used to design the orthogonal test to optimize the solid-state fermentation conditions of the compound feed with evaluations of feed pH,acid soluble protein/crude protein and antibacterial activity.The results showed that the main factors affecting feed fermentation quality were:fermentation temperature>fermentation time>fermentation water content>fermentation inoculation amount.The optimal fermentation conditions were as follows:aerobic fermentation in bags,40%water content of materials,natural pH,1.0×109 CFU/kg inoculum,closed aerobic fermentation in solid state at 37? for 14 days.2.In the process of fermentation,the water content of materials decreased from 40%to 36.64%:The number of effective viable bacteria kept increasing in the first six days,and reached the maximum of 2.93×109 CFU/g on the sixth day.then began to decline,and the content was 7.12×108 CFU/g on the 14th day:The pH value of fed decreased rapidly over the first six days of fermentation,then decreased slowly,and remained stable at about 4.5 at 14 days:During the fermentation period,antibacterial activity continued to rise,increases in the first 12 days were significant,and then entered a stable period.At 14 days,the antibacterial activity was about 1.2 U/g;During the fermentation,the content of lactic acid and acetic acid increased gradually.The content of lactic acid increased noticeably in the first 7 days and then slowed down,reaching 18.31 mg/g on the 14th day of fermentation.There was no obvious fluctuations in acetic acid content and was measured at 35 mg/g on the 14th day.The content of acid soluble protein increased significantly from the second day of fermentation.The content of acid soluble protein/crude protein reached 29.58%after 14 days of fermentation.During the fermentation process,the cellulase activity increased significantly from the 2nd day,and the protease activity and amylase activity increased relatively slowly.After 14 days,the cellulase activity was 290.50 IU/g,the protease activity was 28.66 IU/g,and the amylase activity was 2.61 IU/g.3.15%of the basic diet was replaced by compound feed that has fermented for more than 14 days,and layers that are 400 days old were fed for 2 months.The results showed that the production efficiency of the experimental group was significantly higher than that of the control group.At the beginning of the experiment,there was no significant difference in the egg production rate between the experimental group and the control group.At the end of the experiment,the average egg production rate of the experimental group increased from 72.83%to 75.56%,and the average egg production rate of the control group decreased from 72.73%to 69.83%:The average egg laying rate of the experimental group decreased from 6.12%to 5.86%.and that of the control group increased from 6.21%to 7.74%;The death rate of the experimental group decreased from 0.36%to 0.25%,while that of the control group increased from 0.37%to 0.44%;The egg quality of the experimental group was significantly improved,with an average Hastelloy unit of 78.22,while the control group reached 61.72.4.Immune factors including albumin,immunoglobulin and some cytokines were detected.The contents of albumin,immunoglobulin A,immunoglobulin G and immunoglobulin M all increased in the experimental group,especially IFN-r,IL-2,IL-6 and TNF-?.The thymus index of the experimental group was significantly higher than that of the control group,the pancreas index and spleen index were not significantly different between the two groups,while the liver index of the control group was higher than that of the experimental group.Observation of intestinal villi section showed that the height of ileum villi in the experimental group was higher than that in the control group.and the surface of villi was smoother and the crypt was deeper.In addition,the nitrogen excretion rate and phosphorus excretion rate decreased by 5.07%and 2.03%respectively.5.The diversity of intestinal flora was analyzed by high-throughput sequencing.The results showed that the OTU level of the experimental group was significantly lower than that of the control group.Ace and Chao1 of the experimental group were lower than that of the control group,and Shannon index of the experimental group was higher than that of the control group,which indicated that feeding fermented feed could reduce the intestinal flora abundance and diversity of the experimental layer.At the level of phylum,Firmicutes and Bacteroides,which are beneficial to the health of laying hens,are much higher than other phylum and belong to the dominant group.Bacilli and bacteroidia at the class level are the dominant compendium.At the genus level,Lactobacillus Beijerinck and Prevutella have the highest percentage.In general,the content of probiotics such as bacillus,Lactobacillus and Bacteroides increased in the experimental group compared with the control group,and the content of harmful bacteria such as Escherichia coli and Streptococcus decreased.Feeding fermented feed can improve the intestinal microenvironment of laying hens. |
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