| With the promotion of antibacterial ban and reduction policies,probiotics are gaining more and more attention as an alternative to antibiotics and their ability to improve animal productivity.However,relatively little research has been done in sheep farming,while coccidia,one of the most common parasitic diseases in production,are in the same intestinal environment as gut microbiota,so they are directly related.The aim of the experiment was to observe the effects of complex probiotics on coccidial infection,growth performance,blood physiological and biochemical indexs and immune index in lambs,and to provide practical reference and data support for the use of probiotics in lamb production.1 Investigation of coccidial infection in Hu sheep at different growth stages in a Ruzhou farmIn order to understand the coccidial infection of Hu sheep at different growth stages,179 fecal samples of Hu sheep at different growth stages were examined microscopically by applying saturated sucrose solution floating method and Mc Master counting method,and coccidia were collected and cultured for identification.The results showed that the total infection rate of coccidia in Hu sheep was 71.5%(123/172),and coccidia had a high infection rate at different growth stages,with the highest infection rate of 93.6%(30/32)in adult ewes and the lowest infection rate in lactating lambs.The infection intensity of lactating lambs,weaning lambs and perinatal ewes was higher than that of other production stages,with lactating lambs having the highest infection intensity with an average OPG of 153467.Based on the morphological and structural characteristics of coccidia,a total of 11 species of Eimeria were identified,among which Eimeria ovinoidalis and E.parva were dominant species in sheep of different age classes,and more species were infected in lambs than in adult sheep.The results of this survey provide a scientific basis for reasonable prevention and control of coccidiosis in sheep at different ages.2 Preparation of compound probioticA new compound cream probiotic was designed,screened and prepared by selecting Bacillus subtilis,Enterococcus faecalis,Saccharomyces cerevisiae and Clostridium butyricum.After screening of the cream matrix,the formulation was screened using orthogonal experiments.Finally,the tolerance of the compound probiotic cream and liquid formulation to acid and alkaline environment was determined.The results showed that the best formulation of the cream formulation was 1.5% CMC-Na,2% starch,10% triglyceride,1% soy lecithin,5% glycerol and 0.01% edible milk and apple flavoring.And the composite probiotic cream and liquid formulation were able to survive well in both acid and alkaline environment.3 Effect of compound probiotic on coccidial infection and gut microbiota of lambs84 newborn lambs were selected and fed different doses of cream or liquid probiotic for12 h.42 lambs were artificially infected with coccidia at the 30 th day,and were divided into natural and artificial infection groups.During the experiment,the discharge of coccidial oocysts and fecal status were recorded,and the changes of gut microbiota of lambs before and after coccidial infection were measured by high-throughput sequencing technology.The results showed that: 1)The oocysts of coccidia in lambs fed the probiotic complex were excreted at least as much as in the control group;after coccidia infection,the diarrhea index was lower in the test group fed the probiotic complex than in the control group,except for the CME and LME groups.2)Before infection with coccidia,feeding the compound probiotic improved the richness and diversity of the lamb’s gut microbiome.All experimental groups increased the number of beneficial bacteria to some extent,including Firmicutes,Bacteroides,Lachnospira,Ruminococcus,Parabacteroides,Lactobacillus,etc.3)For lambs naturally infected with coccidia,feeding the complex probiotic had no significant effect on the diversity and abundance of their gut microbiota.Feeding compound probiotic preparations could regulate the dysbiosis of flora caused by coccidia infection to different degrees,reducing Escherichia-Shigella,Succinovibrio and uncultured_Muribaculaceae,and increasing[Eubacterium]_coprostanoligenes_group,Akkermansia,etc.,among which medium and high doses of compound cream probiotic groups had the best effect.4)For lambs artificially infected with coccidia,feeding compound probiotic had no significant effect on the abundance of gut microbiota,but improved the flora diversity.There was a certain degree of dysbiosis in all treatment and control groups,and there was no significant difference in the species and abundance of flora,and there was a certain degree of decrease in Gram-positive bacteria and increase in Gram-negative bacteria in both groups.5)Feeding compound probiotics to newborn lambs can improve metabolic pathways related to cell metabolism,including amino acid metabolism,carbohydrate metabolism,lipid metabolism,etc,promoting body development and immunity.The results suggestted that probiotics can increase the number of beneficial bacteria and control the disorder of microbiome caused by naturally coccidial infection,thus reducing diarrhea symptoms,but the effect of artificial coccidial infection is not obvious,indicating that probiotic preparations are difficult to resist the one-off infection of larger doses of coccidia.4 Effect of compound probiotic on immune performance of lambsThe weight gain was recorded at the end of the experiment,and the blood serum physiological and biochemical indexs and immune index of sheep were measured using conventional immunization techniques and other methods.The results showed that 1)Daily gain in CH group was higher than control group,there was no significant difference between the other treatment groups and the control group.2)After natural infection,the number of leukocytes and neutrophils in the CH group,eosinophils in the CM group,neutrophils in the CH group was significantly higher than control group(P<0.05).After artificial infection,the hemoglobin in the LH group was significantly higher than control group(P<0.05),and the number of erythrocytes in the CH and LH groups was significantly lower than control group(P<0.05).3)The serum total protein content was higher and triglycerides content was lower in serum before coccidial infection than control group;after natural coccidial infection,creatinine was significantly higher in CL and LH groups than control group(P<0.05);after artificial coccidial infection,urea content was significantly lower in CL and CH groups than control group(P<0.05);4)The effects of feeding the compound probiotic on superoxide dismutase content,total antioxidant capacity and Ig G content had no effect;Compared with the control group,the treated group could increase CD4+ and CD8+ levels compared with the control group,with significant differences in the CH and LH groups(P<0.05).The results suggest that probiotics can improve the liver metabolism level,kidney metabolism level,lower cholesterol,and improve cellular immunity,but have no significant effect on antioxidant capacity and humoral immunity.In the natural coccidial infection,the high-dose compound cream probiotic had the best immune-enhancing effect.After artificial coccidial infection,probiotics can play a certain probiotic effect,but the effect was not significant.Comprehensive indicators showed that although feeding compound probiotics to newborn lambs could not reduce the excretion of coccidia oocysts,it could regulate the gut microbiota to some extent,improve hematological indicators and immune-related indicators.And the high-dose compound cream probiotic had a better immune enhancement effect. |
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