Dietary manipulation post weaning to improve piglet performance and gastro-intestinal health

Two experiments were conducted to investigate the use of dietary manipulation as a means of improving piglet postweaning performance and gastro-intestinal health. In experiment 1,144 piglets (24 days old) in a 3 x 2 factorial arrangement were offered diets containing 65, 170 and 280 g lactose per kg with or without lactic acid (16 g/kg) for 28 days. In experiment 2, 20 piglets ( 24 days old) in a 2 x 2 factorial arrangement were offered the following diets for 7 days and then sacrificed: T1) basal diet; T2) basal diet + 15 g inulin per kg; T3) basal diet + 16 g lactic acid per kg and T4) basal diet + 15 g inulin per kg + 16 g lactic acid per kg. After slaughtering, tissue samples were taken from the duodenum, jejunum and ileum for morphological measurements. Digesta samples were taken from the ileum, caecum and colon for microbiology and volatile fatty acid analysis. In experiment 1, pigs offered diets containing lactic acid had improved daily gain (P < 0.01) and food efficiency (P < 0.05) from days 0 to 7 compared with pigs offered diets containing no lactic acid. There was a linear increase (P < 0.05) in average daily gain (ADG) from days 0 to 28 and a linear decrease in faecal pH (P < 0.01) with increasing lactose levels. There was a quadratic effect of lactose on food conversion ratio from days 0 to 28 (P < 0.05). In experiment 2, there was a significant interaction between inulin and lactic acid in villous height in the jejunum (P < 0.001) and the concentrations of lactobacilli (P < 0.1) and E. coli (P < 0.05) in the colon. The inclusion of inulin and lactic acid resulted in a significant increase in villous height compared with the inulin only diet (P < 0.001). However, lactic acid had no effect on villous height in pigs offered diets without inulin supplementation. The inclusion of lactic acid and inulin caused a significant increase in both lactobacilli and E. coli concentrations compared with the inulin only diets (P < 0.05). However, neither inulin nor lactic acid had an effect on lactobacilli and E. coli numbers in isolation of the other. In conclusion, in experiment 1, lactic acid improved performance in the 1st week post weaning. There was a linear increase in ADG with increasing lactose levels. In experiment 2, the combination of lactic acid and inulin increased villous height in the jejunum and concentrations of lactobacilli and E. coli in the colon.