Study On The Application Of Selenium-Enriched Probiotics In Hen Production

Selenium is an essential trace element for animals and human. Its functions include improving immunity, preventing cancer, resisting free radicals, postponing aging, detoxification from some heavy metals, and preventing some local epidemic etc. In many countries, supplementation of selenium in animal diet is a routine step on animal husbandry. Adding sodium selenite as inorganic selenium in animal diet has been set limit in some countries because inorganic selenium has disadvantages of lower biological utilization ratio, higher toxicity and potential environmental pollution. Selenium-enriched probiotics(Se probiotics) is an organic selenium-enriched product which translated inorganic selenium into organic selenium by probiotics fermentation, act as not only organic selenium but also probiotics. The purpose of the present paper was to study the effect of Se probiotics on the production performance, antioxidative function, intestinal microflora, digestive enzyme activities and egg selenium and cholesterol concentrations of hen, and make a guide for the application of Se probiotics in hen production. The research contents were as follows:1. Effects of Se probiotics on the production performance, egg quality and egg selenium concentrations in hens were studied. Seven hundred 58-week old Rohman laying hens were randomly allocated into seven groups, with 5 replicates of 20 hens in each. Se probiotics, sodium selenite and probiotics were added into basal diet at 2 levels respectively. The basal diet was served as control. The experiment lasted for 35 days. During the experiment, production performance was recorded, two eggs per replicate from each group were randomly collected every 7 days for egg Se concentrations analyses, and another 12 eggs per replicate were collected on days 32 to evaluate egg quality parameters. The results showed that, supplementation of Se probiotics significantly increased laying rate(P<0.01), hen day egg production(P<0.01) and mean egg weight(P<0.01), decreased feed/egg ratio(P<0.05). Egg quality of fresh eggs was not affected by the supplementation(P>0.05), but haugh unit measured on eggs stored at room temperature for 5 days was significantly improved(P<0.01). Egg Se concentrations were linearly increased(P<0.01) for the supplementation of Se from either Se source, but at the same supplemental Se levels, eggs from hens fed Se probiotics had higher(P<0.01) Se concentrations than those fed sodium selenite.2. Effects of Se probiotics on antioxidative activities, intestinal microflora and digestive enzyme activities in laying hens were studied. One hundred and forty 65-week old Rohman laying hens were randomly divided into seven groups, with 5 replicates of 4 hens in each.Experiment treatment as before. During the experiment, blood was sampled on days 15 and 35 for whole-blood GSH-Px activity, plasma SOD and T-AOC activity assay. At the end of the experiment, two hens per replicate from each treatment were slaughtered for the quantitation of cecal microflora and estimation of digestive enzyme in intestinal contents. The results showed that the addition of Se probiotics or sodium selenite to the diet significantly increased(P<0.01) the whole-blood GSH-Px activity, plasma SOD activity and T-AOC in comparison to the control. There was a more significant increase(P<0.05) in whole-blood GSH-Px activity and T-AOC from hens fed Se probiotics than those fed sodium selenite. Supplementation with Se probiotics or probiotics significantly increased the amouns of cecal Lactobacillus(P<0.01) and Bifidobacterium(P<0.05), decreased the amouns of cecal Escherichia coli(P<0.01), Staphylococcus(P<0.01) and Enterococcus(P<0.05). Either Se pobiotics or probitics increased significantly the levels of amylase(P<0.01) and lipase(P<0.05) activties in duodenum contents. However, the trypsin and protease activities were not affected by addition of either Se-pobiotics or probitics.3. Effect of Se probiotics on lipid metabolism in hens were studied. Experiment animals and treatment as before. At the end of the experiment, two eggs per replicate from each treatment were collected for measuring yolk cholesterol, and blood was sampled from each of 2 hens in each replicate, the sera were separated for estimation of serum total cholesterol(TC), high density lipoprotein cholesterol(HDL-C), low density lipoprotein cholesterol(LDL-C) and total triglycerides(TG). The results showed that, the addition of Se probiotics significantly ruduced(P<0.01) the contaitions of serum TC, LDL-C and yolk cholesterol. However, no difference in these traits was observed between the groups receiving different levels of Se probiotics. Serum TG and HDL-C were less affected by Se probiotics.