Determination of the Nutritive Value of Tropical Biomass Products as Dietary Ingredients for Monogastrics Using Rats: 1. Comparison of Eight Forage Species at Two Levels of Inclusion in Relation to a Casein Diet

Phuc, Bui Huy Nhu; Lindberg, Jan Erik; Ogle, Brian; Thomke, Sigvard

doi:2001.14.7.986

Article

Swine Nutrition and Feed Technology

Asian-Australasian Journal of Animal Sciences 2001;14(7): 986-993.
https://doi.org/10.5713/ajas.2001.986 Published online July 1, 2001.

Determination of the Nutritive Value of Tropical Biomass Products as Dietary Ingredients for Monogastrics Using Rats: 1. Comparison of Eight Forage Species at Two Levels of Inclusion in Relation to a Casein Diet

Bui Huy Nhu Phuc, Jan Erik Lindberg, Brian Ogle, Sigvard Thomke

Abstract

In balance experiments with rats either 25 or 50% of the casein protein in the control diet was replaced with one of the following eight sun-dried tropical biomass products: water spinach plants (WS) (Ipomoea aquatica Forsk), leucaena leaves (LL) (Leuceana leucocephala), duckweed plants (DW) (Lemma minor L.), groundnut foliage (GF) (Arachis hypogaea L.), trichantera leaves (Tric) (Trichantera gigantea), indicago leaves (Ind) (Indigofera hirsuta), mungbean foliage (Mb) (Phaseolus aureus), and cassava leaves (CL) (Manihot esculenta Crantz). The experiment included 102 rats with six individuals per treatment group. In three of the 16 biomass treatment groups, feed intake and weight gain of the rats were unacceptably low, and therefore they were excluded from the statistical evaluation. The crude protein (CP) content of the biomass products varied between 20.9% (Tric) and 33.2% (DW), whereas the content of NDF varied between 18.5% (Ind) and 32.2% (DW) of dry matter (DM). The total content of essential amino acids (g/16 g N) was comparable with that of alfalfa meal, except for GF and Tric, which were inferior. Between plant species, differences in dietary digestibility of organic matter (dOM) and CP (dCP) were observed (p<0.001). Also, the replacement level negatively influenced dOM and dCP (p<0.001). The lowest values for dOM (p<0.001) were observed for diets including biomass products with the highest content of NDF (GF, Tric, Mb, LL). Digestibility of CP was negatively affected by level of protein replacement. Significant (p<0.001) differences were found in N-retention and biological value among diets with different biomass products. The most favourable overall results were obtained for DW, WS and CL. The main factors affecting the nutritive value of the diets tested were their NDF content, dCP and AA profile of the biomass. Also antinutritive component(s) may have influenced the process of digestion and metabolism of some of the biomass products.

Keywords: Tropical Biomass; Nutrient Digestibility; Product Quality; Biological Value; Rats