Effects Of Benzoic Acid And Thymol On Growth Performance And Gut Health In Piglets

Animal food safety problem resulting from feeding antibiotic for animals become more and more serious. Development of antibiotic alternatives is the goal for animal scientists. Benzoic acid and thymol are among the potential alternatives, but there has been little research about them on piglets up to now. The experiment was conducted to investigate the effects of different concentrations/combinations of benzoic acid and thymol on growth performance and intestinal microecology in weaning piglets fed with barley-wheat-soybean-based diet. A total of180healthy DLY weanling piglets (weaned at day24) with an initial average body weight of (6.03±0.78) kg were allocated to5treatments with6replicates per treatment and6pigs per pen with randomized complete block design, with the respective treatments being basal diet(treatment1), basal diet+1000mg/kg benzoic acid+100mg/kg thymol (treatment2), basal diet+1000mg/kg benzoic acid+200mg/kg thymol (treatment3), basal diet+2000mg/kg benzoic acid+100mg/kg thymol (treatment4) and basal diet+5000mg/kg benzoic acid(treatment5) in the diets with no antibiotics. The whole trial was last for42days. On days39～42, digestion experiment was carried out with endogenous indicator. On day14and day42, one piglet chosen from each replicate was blood, killed and sampled. The results were as follows:1.When compared with treatment1, treatment4and treatment5decreased the feed:gain during days1～14,1～28and1-42(P＜0.05), treatment2, treatment4and treatment5decreased the diarrhea score (P=0.09).2.When compared with treatment1, the digestibility of CP, Ca and energy in other treatments and the digestibility of EE, P and crude ash in treatment4increased (P＜0.05).3.When compared with treatment1, treatment4and treatment5increased the activities of trypsin, lipase, amylase, maltase, sucrose and lactase of digesta in jejunum on14th day and lipase, lactase and sucrase of digesta in jejunum on42th day(P＜0.05). The activities of trypsin, lipase, amylase, maltase and lactase of digesta in jejunum on14th day in treatment2and the activities of lipase of digesta in jejunum on42th day in treantment3increased (P＜0.05).4.When compared with treatment1, the content of NH3-N (P＜0.01) in serum of other treatments decreased on14th day, the content of Ca (P＜0.05) in serum of other treatments increased on42th day. Treatment4and treatment5increased the content of T3in serum on14th and42th day(P＜0.01) and decreased the content of TG (P＜0.05) in serum on42th day. Treatment5decreased the content of NH3-N (P＜0.01) in serum on42th day.5.When compared with treatment1, other treatments decreased the pH of digesta in colon on14th day and treatment5decreased the pH of digesta in cecum on14th day (P＜0.05). Treatment5decreased the pH of digesta in colon on42th day (P=0.07).6.When compared with treatment1, treatment4increased the number of lactobacillus in ileum on14th and42th day (P＜0.05). Treatment2and treatment5increased the number of Bifidobacterium in ileum on14tt day (P＜0.05). The number of Bacillus in cecum in other treatment on14th day increased (P＜0.01). The number of Escherichia coli in ileum and cecum on42th day decreased (P＜0.05). Positive control group decreased the number of Enterococci in ileum on14th day(P＜0.01).7. When compared with treatment1, treatment4and treatment5increased the content of propionic acid and total VFA in cecum on14th day (P＜0.05). Treatment4increased the content of butyric acid in cecum on42th day (P＜0.05). The content of NH3-N in cecum on14th day and42th day decreased (P＜0.01).8.When compared with treatment1, treatment4and treatment5increased villous height and v/c in jejunum and v/c in ileum on14th day (P＜0.05). Treatment5increased v/c in duodenum and jejunum on42th day (P＜0.05). Treatment4increased villous height in ileum on14th day (P=0.07), treatment5increased villous height in jejunum (P=0.05) and v/c in ileum (P=0.08) on42th day.9. When compared with treatment1, other treatments decreased the content of MDA in serum on14th and42th day (P＜0.05). Treatment4and treatment5increased the content of IgG in serum on14th (P＜0.05). These data indicated that:1.Piglets fed diet supplemented with different concentrations/combinations of benzoic acid and thymol could improve growth performance through improving the apparent digestibility, activities of digestive enzymes and effecting serum biochemical, antioxidant and immune parameters.2. Piglets fed diet supplemented with different concentrations/combinations of benzoic acid and thymol could reduce gut pH, increase the number of lactobacillus, Bifidobacterium and Bacillus, reduce the number of Escherichia coli, maintain intestinal morphology, and thus improve gut health.3.The suitble diet for optimal growth performance and intestinal microecology of piglets (weaned at24d) was5000mg/kg benzoic acid group. Dietary (barley-wheat-soybean-based diet) supplementation with2000mg/kg benzoic acid+100mg/kg thymol for piglets could increase feed efficiency, decreases diarrhea incidence and improve gut microfloral composition to the extent close to that of5000mg/kg benzoic acid.