Effects on growth performance, feed efficiency, and health of weanling pigs fed fermented liquid whey inoculated with lactic acid bacteria that inhibit Escherichia coli in vitro

Objectives: To determine the fermentation dynamics of liquid whey-dextrose (FLWD) inoculated with lactic acid bacteria (LAB) and whether feeding FLWD inoculated with LAB and added to a basal dry diet without antibiotics affects growth, feed efficiency, and health of weanling pigs. Materials and methods: One hundred and forty newly weaned pigs were assigned to five dietary treatments (four pens of seven pigs per treatment). Three FLWD preparations inoculated with either human- or pig-origin LAB strains were added to a basal dry feed. The fourth FLWD preparation contained no LAB. The fifth diet was the basal dry feed containing 0.1% lincomycin (control). LAB strains were mixed with FLWD prior to fermentation. Dry matter (DM), pH, and LAB counts of diets were measured daily during the 5-day fermentation period and the first 2 days of storage. Growth performance was recorded and rectal swabs were collected weekly. Fecal consistency was evaluated daily. Results: The pH and DM of fermented feed decreased and total LAB increased over time. Average daily gain and feed intake were highest in controls. Prevalence and severity of diarrhea were greater in pigs consuming LAB-inoculated diets than in control pigs. Mortality did not differ among treatment groups. Fewer hemolytic Escherichia coli were recovered from pigs fed FLWD. Implications: Fermented liquid feeds do not consistently promote better growth performance and health in weanling pigs. Use of LAB in starter feed may inhibit enteric E coli; however, further studies are needed to determine whether specific strains of LAB may prevent postweaning diarrhea.