Studies On Formulation Of Complex Acidifier And Its Effect In Weaned Pigs

Acidifiers are widely used in feed, especially in feed of weaned pigs. However, there are still disputes on effect and mechanism of acidifier. Therefore, the two experiments were hereby to set up to investigate the formulation of complex acidifier and its mechanism in weaned pigs.Experiment 1: Study on Formulation of Complex AcidifiersThe uniform design method was employed to study the formula of acidifier. The two kinds of acidifiers, i.e. phosphoric acid (acidifier A) and the lactic acid (acidifier B), with 6 different formulas each were formulated. The pH value, feed acid binging force, and the bacteriostasis effects among different treatments were determined. The stepwise regression method was used to deal with determined values of different treatments.The result indicated it had optimum effects when phosphoric acid, citric acid, fumaric acid, and calcium formiate accounted respectively for 30％, 20％, 20％, and 5％in acidifier A. However, it had best effects when lactic acid, eitric acid, and fumaric acid accounted respectively for 40％, 20％and 20％in acidifier B.Experiment 2: Mechanism of Acidifier on Promoting Growth of Weaned PigsThe experiment was conducted to study the effect of acidifier developed in experiment 1 and its mechanism in weaned pigs. Two-hundred weaned pigs were divided into five groups randomly. Group one (a negative control) was fed the diet without acidifiers, the other groups were fed the diets with 0.1％, 0.3％phosphoric acid type acidifier (acidifier A) and 0.1％, 0.3％lactic acid type acidifier (acidifier B). Feed intake, weight gain, average daily weight gain (ADG), feed efficiency, and occurrence of diarrhea of each group were measured. Three piglets were randomly selected from every treatment at the end of four week experiment for slaughter test to determine the pH of digestive tract, activities of digestive enzymes, small intestine morphology, large intestinal microflora, serum biochemical parameter, and immune index. The main results are as follows:①Two acidifiers added in the diets significantly increased average feed intake (P＜0.05), daily wight gain (P＜0.05), remarkably improved feed efficiency (P＜0.05) and decreased the diarrheoa rate (P＜0.05). Among all the treatments, it was the best one when 0.3％of acidifier B was added to the diet based on the performance;②Two acidifiers added in the diets significantly decreased the pH value in stomach and duodenum (P＜0.05), increased the activities of pepsin, trypsin in duodenum (P＜0.05), increased the length of intestinal villi (P＜0.05); Two acidifiers added in the diets significantly decreased E.coli counts and salmonella counts (P＜0.05), increased lactobacillus counts and bifidobacteria counts (P＜0.05). It seems that acidifier B was better than acidifier A based on the current measurements;③Two acidifiers added in the diets had no significant effects on the content of serum total protein (P＞0.05). The dietary addition of acidifier at 0.3％significantly decreased the content of serum urea nitrogen (P＜0.05). Both of two acidifiers added in the diets significantly increased the content of serum IgA and IgG (P＜0.05). However, the serum IgM content and the ratio of CD4~+/CD8~+ were not significantly affected by the types ofacidifiers (P＞0.05).In conlusion, two acidifiers added in the diet of weaned pigs improved growth performance. Aicidifier B was better than acidifier A. It seems that the optimum supplemental level of acidifier B was 0.3％.