Acetic acid is not involved in enhanced intestinal protein synthesis by the presence of the gut microflora in chickens

Modification of energy metabolism by the presence of the gut microflora in the chicken

Whether the association with gut microflora modifies the energy metabolism of chickens was investigated by varying the metabolizable energy consumption level from zero to above the maintenance requirement in the germ-free and conventional states. Single comb White Leghorn chicks were either fasted for 3 d (Expt 1), or fed for 6 d at a fixed daily meal intake of 2, 5 or 8 g/d (Expt 2), or 5, 10 or 15 g/d (Expt 3). Changes in carcass energy deposition and heat production indicated that when no dietary energy was available the presence of the gut microflora could benefit the birds by reducing energy losses, whereas when dietary energy was supplied the efficiency of energy utilization was reduced by the presence of the gut microflora. It was concluded, therefore, that the heavy burden of the gut microflora modifies energy metabolism by exerting a buffering or a counter-productive action on the energy utilization of the chicken.

Research note: fructose feeding increases lower gut weights in germ-free and conventional chicks

The present study was conducted to investigate whether there was any effect of carbohydrate sources on the magnitude of differences in growth and tissue weights found between germ-free and conventional environments in the chicken. Germ-free and conventional birds were allowed free access to a purified diet in which glucose or fructose was used as a sole carbohydrate source from 7 to 17 days of age. Growth performance and visceral weights were measured at the end of the experiment. The results indicated that there was no difference in growth, feed intake, or feed efficiency between the two environments, but that feeding fructose increased feed intake and decreased feed efficiency compared with feeding glucose. The conventional birds had heavier visceral organ weights including liver, jejuno-ileum, and cecum than did the germ-free counterparts. Feeding fructose resulted in lighter liver weight and heavier weights of jejuno-ileum and cecum than feeding glucose. It was concluded that consuming fructose might increase the lower gut weight of the chicken, as was found by the association with normal microflora, but might not affect overall growth compared with consuming glucose.