Effects Of Dietary Protein And Zinc Level On Performance, Microbial Diversity And Their Metabolites In Intestinal Tract Of Early-weaned Piglets

When fed with high CP content diets, performance of early-weaned piglets is improved, which is always associated with high incidence of diarrhea. It is very important to settle this contrary for increasing economic returns. As a result, 32 crossbred piglets ([Yorkshire×Landrace]×Duroc), with an initial BW of 6.3±0.4kg and weaning at 21 days of age, were randomly allocated 4 dietary treatments according to a 2×2 factorial experiment, 2 levels of CP (23% or 17%) and 2 contents of Zn (100mg or 3000mg Zn/kg diet) from ZnO. It was conducted to evaluate the effects of different dietary CP and Zn level on performance, blood biochemical indicators, diversity of microbes and their metabolites in intestinal tract, the availabilities of nutrients and diarrhea of early-weaned piglets were also exzamed. The duration was 28 days. The results indicated that:1,Dietary protein and zinc regulated microflora in intestinal tract of weaned piglets. Data of PCR-DGGE analysis indicated that high-CP diets increased variety of microbes and pharmacological concentrations of Zn decreased it when piglets fed with high-CP diets. However, low-CP with 100mg/kg Zn might affect this stability.2,When fed diets with high CP, the concentrations of metabolites of microbes, such as volatile basic nitrogen, ammonia nitrogen and lactic acid were increased in intestinal tract of piglets. Diets supplemented with pharmacological concentrations of Zn decreased those metabolites, which indicated that Zn can inhibit metabolic activity of microbes.3,The effects of diets with different CP content supplemented with pharmacological concentrations of Zn on performance and diarrhea of early-weaned piglets were different. High-CP diets improved performance significantly, but caused much more serious diarrhea, compared to low-CP. Pharmacological concentrations of Zn increased growth performance, but also decreased frequency and incidence of diarrhea (P<0.01), which was due to the increase of availability of nutrients.In conclusion, supplementing pharmacological concentrations of Zn to diets with high CP content benefits to decrease diarrhea, increase availability of nutrients and improve performance of early-weaned piglets. The effects of Zn are due to its ability to change constitution of microbial population in intestinal tract and to inhibit metabolic activities of microbes to decrease the content of harmful metabolites. As a result, the availability of nutrients and gut health were improved in host.