Effects of dietary oligosaccharides on the growth performance and faecal characteristics of young growing pigs

The effects of dietary fructo-oligosaccharides (FOS) and trans-galacto-oligosaccharides (TOS) were studied on growth performance and faecal characteristics of young growing pigs. FOS and TOS are non-digestible oligosaccharides (NDOs); they are not hydrolyzed by enzymes of endogenous origin, but are readily available as substrate for the gastrointestinal microflora. Dietary levels of NDO-rich products were 7.5 and 15 g kg(-1) diet for FOS, and 10 and 20 g kg(-1) diet for TOS. NDOs were included in an experimental corn-based control diet, which was low in NDOs (190 mg raffinose kg(-1)) and contained no additional copper, antibiotics or probiotics. NDO-rich products were included at the expense of glucose and purified cellulose. Resulting five experimental diets were fed ad libitum to 9-week old castrated male piglets (n = 10) with an initial body weight (se) of 15.6 +/- 0.3 kg. Rigs had received the control diet for 19 days before reaching this body weight. Individual body weights and feed refusals were recorded every 3-4 days during six weeks. Fresh faeces were rectally collected at day(0), day(14), and day(35), and analyzed for NDOs, pH, and dry matter content. Dry matter intake and body weight gain of the NDO-fed pigs were lower than the control pigs (P = 0.039 and P = 0.031, respectively) in week one through three. Dietary NDOs did not affect mean growth performance in week one through six. FOS and TOS could not be detected in the faeces. Dietary NDOs did not affect faecal pH. Faecal pH increased with time (P < 0.01). NDO-fed pigs had a lower faecal dry matter content than control pigs (P = 0.062). Pigs fed TOS-rich diets had a lower faecal dry matter content than pigs fed FOS-rich diets (P = 0.061). It is concluded from this experiment that exchanging cellulose for NDOs in young growing pigs' diet results in a temporary depressed feed intake with little or no effects on faecal dry matter content and pH. (C) 1998 Elsevier Science B.V.