| A Pediococcus acidilactici strain was isolated from the intestine of cultured Macrobrachium rosenbergii,then M rosenbergii was fed with dietary microbial ecological agents,to investigate the effects of P.acidilactici,saccharomyces and beta-glucan single/compound on the growth performance,feed utilization,digestive enzymes,immune activity and intestinal health of.rosenbergii,the main results of the present study are shown as follows:1.the selection and identification of P.acidilactici.10 prawns(about 10g)were collected from the M rosenbergii pond,and the intestinal contents were separated and cultured on MRS.Three strains of dominant lactic acid bacteria were determined based on the results of physiological and biochemical experiments,then the inhibition experiment of Aeromonas hydrophila was carried out.The GYP with the maximum inhibitory zone was identified as P.acidilactici by 16S rDNA.2.Effects of microbial ecological agents on the growth,feed utilization,body composition and digestive enzymes of M rosenbergii.2560 juvenile M.rosenbergii(0.19±0.01 g)were randomly divided into eight groups,replicated in four,80 prawns each parallel.The experiment was carried out by feeding feeds containing different microbial ecological agents for 60 days.Among them,Gc group was the control group,Gs group was saccharomyce group,Gg group was beta-glucan group,Gp group was P.acidilactici group,Gsg group was saccharomyce +beta-glucan group,Gps group was saccharomyce +P.acidilactici group,Gpg group was beta-glucan+P.acidilactici group,Gpgs group was saccharomyce+beta-glucan+P.acidilactici group.Compared with the Gc group,the Gs group,the Gsg group,the Gps group and the Gpgs group could significantly increase the growth rate and specific growth rate of M.rosenbergii(P<0.05),and reduced the feed conversion rate(P<0.05).The amylase activity of the Gg group and the Gps group were highest(P<0.05),the lipase activity of the Gg group,the Gps group,the Gpg group and the Gpgs group were significantly increased(P<0.05),the protease activity of the microbial ecological agents groups were significantly higher than the Gc group(P<0.05),Except the muscle water in Gs group was significantly higher than the the Gc group(P<0.05),there were no significant difference in muscle moisture,crude protein,crude fat and ash content between the microbial ecological agents groups and the Gc group(P>0.05),the content of essential amino acids in M rosenbergii were significantly higher in the microbial ecological agents groups than the Gc group(P<0.05).3.Effects of microbial ecological agents on immune activity and Intestinal health of M.rosenbergii.The results showed that the addition of microbial ecological agents in feed could significantly improve phagocytosis activity of M rosenbergii(P<0.05),the total blood cell count(THC)in Gp,Gps,Gpg and Gpgs groups were significantly higher than other groups(P<0.05),the respiratory burst activity in Gg,Gpg and Gc groups were significantly lower than Gs and Gps groups(P<0.05);the results of serum immunoenzyme activity assay showed that the PO in Gsg,Gps and Gpgs groups were highest,there were no significant difference in LZM activity between Gsp,Gpg and Gpgs groups and the control group(P>0.05),while other microbial ecological agents groups were significantly higher than the control group(P<0.05),the CAT in Gs group,Gg group and GP group was highest,the NOS in Gpg group and Gpgs group were highest(P<0.05);the SOD in Gpgs group was highest(P<0.05;The results of hepatopancreas immunoenzyme activity assay showed that:Compared with Gc group,the LZM in Gs group,Gg group,Gp group and Gsg group were increased(P<0.05),the CAT in Gpgs group and Gg group were significantly higher than the Gc group(P<0.05),the NOS in Gp group,Gsg group and Gpgs group were highest(P<0.05),the SOD in Gp group,Gsg group,Gps group and Gpgs group were significantly higher than other groups(P<0.05);The results of A.hydrophila challenge showed that:there were significant difference in the cumulative mortality of M rosenbergii after 7 days(P<0.05),among them,the cumulative mortality of Gps group was significantly lower than the Gs,Gg and Gc groups(P<0.05),and there was no significant difference between Gs group,Gg group and Gc group(P＞0.05);The results of intestinal tissue sections showed that:the intestinal wall thickness,villus width and villus height of M.rosenbergii were significantly higher in the microbial ecological agents groups than the control group(P<0.05),and the intestinal wall thickness of Gpgs group was the largest(P<0.05),the villus width of Gs group and Gpgs group was the highest(P<0.05),and the villus height of Gpgs group was the largest(P<0.05). |
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