Metabolizable energy content of fresh water plants in chickens and ducks. Poultry Sci

ABSTRACT Apparent and true metabolizable energy (AME, TME) contents of five species of dehydrated freshwater plants and dehydrated alfalfa were determined using White Leghorn roosters. True metabolizable energy was also determined using White Pekin ducks. The AME values of aquatic plants, except the duckweed were much lower than alfalfa. Duck-week contained lower but comparable levels of both AME and TME to alfalfa. Watermilfoil had no metabolizable energy value for the rooster. The TME values were higher than AME's for all species of plants. The TME values of aquatic plants in ducks were also lower than alfalfa but the differ-ences were not as great as with the roosters. The TME values of pondweed and Vattisneria in the two species of birds were similar while the differences fluctuated for other plants. Ducks metab-olized watermilfoil much better than roosters. The aquatic plants used in this study were very high in ash, thus reducing their potential energy and perhaps adversely affecting the ability of the birds to utilize the energy present. The AME value of each of the aquatic species and alfalfa at the various levels of substitution was calculated but the results obtained were very variable. In order to get reliable results AME values were obtained from regression equations; these equations would be useful in predicting the M.E. content of diets containing the species of plants studied; their use would, however, be limited only to plant materials with similar ash contents to those found in this study