Effect of Lactobacillus acidophilus on starter pigs fed a diet supplemented with lactose.

Seventy-two crossbred pigs (average initial weight 6 kg) were used to study the effect of L. acidopbilus (lactic acid-producing bacteria common in probiotics) in starter diets on gain, feed conversion, fecal lactobacillus and coli-form counts, hematology and serum proteins. The nonmedicated experimental diets were corn-soybean meal (18% crude protein) diets with two levels of lactose (0 and 10%). It has been theorized that lactose is necessary for lactobacilli to colonize in the digestive tract. One-half of the pigs received a 10-ml inoculum daily for 2 weeks via stomach tubes. Two inocula were used: water (control) and L. acidopbilus (LA) culture strain DDS 1 (2 x 101~ viable cells/ml). The pigs that did not receive an inoculum were assigned to a diet with or without Probios (4 x 106 viable cells/g), a LA feed additive. The experimental treatments were: (1) control, (2) Probios, (3) water inoculum, (4) acidophilus inoculum, (5) lac-tose + Probios, (7) lactose + water inoculum and (8) lactose + acidophilus inoculum. Gain and feed conversion were not significantly affected by treatments. There was a trend toward improved average daily gain (ADG) with lactose and Probios. The water inoculation reduced ADG by 14.4% in relation to the performance of pigs receiving the other diets. This reduction in ADG appeared to be related to the extrinsic stress caused by the inoculation process. Also, the stress of the inoculation affected fecal flora by reducing lactobacilli (P<.05) and increasing coliforms (P<.05). L. acidopbilus inoculum improved ADG (11.0%) and feed conversion (1.5%). Although the probiotic *Published as paper no. 5879, Journal Ser., Ne-braska Agri. Exp. Sta. 2 Dep. of Anim. Sci. Acknowledgement is made to Debbie Koester and Alice Teter for their assistance in products tended to improve ADG (7.2%), LA therapy may have been a function of the dietary carbohydrate source. The LA inoculum increased (P<.05) fecal lactobacillus counts. After the daily inocula were discontinued, an increase in lactobacilli was observed for the water-inoculated group, and a decrease in lactobacilli was noted for the microbe-inocu-lated group. Pigs receiving lactose in combination with the lactobacillus inoculum had the highest lactobacillus counts and the best ADG. Probios did not affect (P>.05) fecal lacto-bacillus counts. Neither L. acidopbilus inoc-ulum nor Probios was effective (P>.05) in suppressing E. coll. Lactobacillus treatments did not affect (P>.05) red or white blood cell counts, serum proteins (albumin and globulin) or blood urea nitrogen.