The effects of several oligosaccharides on growth performance, nutrient digestibilities, and cecal microbial populations in young chicks

Two experiments were conducted with New Hampshire x Columbian chicks fed a corn-soybean meal diet and 1 experiment was conducted with chicks fed a dextrose-isolated soy protein diet to examine the effects of inulin, oligofructose, mannanoligosaccharide (MOS), short-chain fructooligosaccharide (SCFOS), and transgalactooligosaccharide on growth performance, ME_n, digestibility of amino acids (AA), and cecal microbial populations. Each diet was fed to chicks from 0 to 21 d of age, and excreta were collected at 3-4, 7, 14, and 21 d of age in both experiments. Neither 4 nor 8 g of oligosaccharides/kg had a significant effect on growth performance. The ME _n and AA digestibility values increased with increasing age. Feeding 8 g/kg of inulin and SCFOS had a negative effect (P < 0.05) on ME_n at most ages, and 8 g/kg of most of the oligosaccharides reduced (P < 0.05) digestibility of AA at various ages. In experiment 2, 4 g/kg of SCFOS, MOS, and transgalactooligosaccharide significantly reduced ME_n at 3 to 4 d, but most oligosaccharides increased (P < 0.05) ME_n values at 7, 14, and 21 d. The effects of oligosaccharides (4 g/kg) on AA digestibility were generally small and inconsistent. Feeding corn-soybean meal diets containing 4 g/kg of oligosaccharides had no significant effect on cecal Bifidobacterium, Lactobacillius, Clostridium perfringens, or Escherichia coli populations in 21-d-old chicks. In a third experiment, cecal populations of C. perfringens were reduced when SCFOS and MOS were supplemented at 4 g/kg into a dextrose-isolated soy protein diet. These results indicate that a low concentration (4 g/kg) of an indigestible, prebiotic oligosaccharide can be fed with no deleterious effects on ME_n and AA digestibility. Feeding a higher level of an oligosaccharide (8 g/kg), however, may depress ME_n and AA digestibility.