Effects of lactulose (lac) as feed additive on chyme and feces quality in pigs (reared piglets: n= 10; fattening pigs: n= 20) were tested.
Furthermore, fattening pigs were experimentally infected with Salmonella Derby (orally 2.6× 108 cfu/pig, single dose infection on 1 day)
to examine potential prophylactical effects. Pigs were fed a conventional diet ad libitum (in the control group without lac, in the
experimental group including lac: 28.6/26.9 g lac/kg dry matter). In piglets and fattening pigs lac intake did not alter fecal dry matter
(DM) content or feces pH. Contrary to findings in human beings only small amounts of lac reached the hindgut, although higher lac
concentrations were measured in ileal chyme (in piglets: 10–40 g, in fattening pigs 40–70 g lac/kg DM of chyme). Lac ingestion led
neither to increased concentrations of lactic acid or volatile fatty acids (vfa) nor to reduced pH data in chyme of small intestine, but in
cecum and colon contents higher vfa concentrations (significant effects in piglets) were measured. Furthermore, lac ingestion resulted in
reduced ammonia levels in small and large intestine contents. But no protective effects of lac ingestion were recognized when fattening
pigs were infected orally with Salmonella Derby. Due to the fact that only parts of lac reach the hindgut there are doubts, whether lac can
lead to comparable dietetic effects in pigs as known from human beings (laxation, forced elimination of bacteria a.s.o.). The obtained
results in pigs underline the necessity of experimental studies in the target species before substances are used and recommended for
dietetic purposes in feeding of pigs.
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