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Effects of dietary supplementation of direct fed microbial on growth performance, nutrient digestibility, blood profiles, fecal microflora and noxious gas emission in nursery pigs
A total of 128 weanling pigs [(Yorkshire × Landrace) x Duroc] with an average BW of 6.75 ± 0.59 were used in a 42-d experiment to investigate the efficacy of Bacillus spp. direct-fed microbial (DFM) on growth performance, indices of gut health and nutrient utilization in piglets. Pigs were allotted to experimental diets based on BW in a completely randomized block design. There were two dietary treatments: NC, basal diet (corn-soybean meal based diet); DFM, NC + DFM (1.5 x 105 cfu/g of feed). The DFM product was based on 1 strain of B. subtilis and 2 strains of B. amyloliquefaciens specifically selected and optimized for high enzyme production (Danisco Animal Nutrition, Marlborough, Wiltshire UK). The diets were fed during the experiment in 2 phases: d 0 to 14, and 15 to 42. All diets, in pelleted form, were formulated to meet or exceed the nutrient requirements (NRC, 1998) for weanling pigs. Feed intake and BW were monitored weekly. We used 0.20% chromium oxide as indigestible marker and fecal samples were collected via rectal massage. Incidences of diarrhea were monitored in phase using a fecal scoring system (1 hard to 5 watery). At the end of each phase two pigs/pen were bled for serum and fresh fecal samples were collected. At the end of the experiment, one pig/pen was killed to obtain small intestinal tissues for histomorphology and large intestinal digesta for select microbial counts. In the overall (d 0-42), pigs fed DFM had better G:F (0.694 vs. 0.680, P = 0.04) and tended to have a higher ADG (425 vs. 417 g/d, P = 0.08) compared to the NC fed pigs. Pigs fed DFM showed lower incidences of diarrhea (P = 0.01) than NC fed pigs on d 4. Duodenum and jejunum villi length of pigs fed DFM diets were longer (P < 0.01) than for pigs fed NC diet. Cecal digesta Lactobacillus counts tended to be higher (P = 0.06) in pigs fed DFM compared to the NC pigs, however, Lactobacillus and E. Coli counts in the colon digesta were unaffected by the dietary treatments. Pigs fed DFM tended (P< 0.09) to have higher apparent total tract digestibility of crude protein and lower fecal ammonia release coinciding with low blood urea nitrogen (BUN) concentration than the NC fed pigs. In conclusion, DFM supplementation improved growth performance and efficiency in nursery pigs linked to improved nutrients utilization and indices of gut health and function.
Keywords: weanling pigs; growth performance, gut health