Effects Of HMB On Performance Of Piglets Weaned At D28 And The Buffer Capacity Of Diet

This thesis were composed of two experiments and studied the effects of HMB on pathogenic microbes, the buffer capacity of diets and the performance of piglets.Experiment one: the effects of HMB on pathogenic microbes were tested by the tubes dilution method and used the hydrochloric acid titration method to tested the the the buffer capacity of diets. The results showed :Esherichia coli 0157, 08 0149, salmonellosis,clostridium welchii, Aspergillus flavusjfusarium were tested by the tubes dilution method in the microbes test, the mininum inhibitory concentration (MIC) of HMB for the Esherichia coli, salmonellosis and clostridium welchii during were 1000-1400ppm and the minimum bactericidal concentration for them were 1200-1400ppm. the mininum inhibitory concentration (MIC) of HMB for Aspergillus flavus and fusarium during were 3500ppm and 2000ppm respectively,the minimum bactericidal concentration for them were 4000ppm and 2000ppm.During 1-6 weeks,compared to CON, both 0.114% HMB and 0.228% HMB enhanced ADG (average daily gain) and feed efficiency significantly (P<0.05). The effect of 0.228% HMB was the best in all the treatments . treatments of HMB were better than the 0.100%Met, increased the growth rate about 2.11%-12.14%, increase average daily feed intake about 1.16%-4.44% and decreased feed efficiency about 1.02%-8.24%; compared to 0.300% compound acidifier, increased the growth rate about 4.82%, treatments of 0.228%HMB increase average daily feed intake about 1.35% and decreased feed efficiency about 2.67%; in 7-8 week , The treatments had no improved effect on the performance except 0.114%HMB.When using HMB appropriately in the early-weaned piglets' diet, the diarrhea rate decreased significantly (p<0.05). The diarrhea rate of treatments of 0.114%HMB and 0.228%HMB decreased about 10.19% and 12.23% compared to CON respectively; compared to 0.100%DL-Met, treatments o f 0.114%HMB and 0.228%HMB decreased about 15.39% and 17.32% respectively; and had no difference when compared to 0.300% compound acidifier.The HMB (Rhodimet AT88, Adisseo) could be used as acidifier in the early-weaned piglets' diet. The effect on the performance in first few weeks is better than the later. When the supplementation time exceeded 6 weeks or the supplementation dosage higher, the effect of HMB on the performance or the growth of the piglets reduced, which showed that the use of HMB had a appropriate time phase when used as acidifier.