Sarria et al., 1995. Livest. Res. Rural Dev., 7 (3): 6
Three experiments using 120 day-old broiler chicks, were carried out using a method designed to evaluate quality of protein from non-conventional sources, such as aquatic plants and leaves of trees. This work was done at the senior author's home located in Cali (Colombia) from June to August of 1995. The area is 1000 m above sea level with 24 ?C daily mean temperature, 75% humidity and 1000 mm annual rainfall. A chick growth asay is an attractive biological test because results are obtained within two to three weeks after giving the test protein. Energy sources free of protein were used to ensure that the growth response reflected the quality of the test protein. The protein sources to be evaluated were included at levels that permitted replacement of between 0 and 15% of the protein in soya bean meal.
The first experiment compared a basal diet based on cereals with one in which the energy source was provided by raw sugar and palm oil; in both diets the protein source was soya bean meal. Intake and growth on the sugar/oil diet were low, compared with the cereal diet (21 vs. 38 g/d of intake; 4 vs. 24 g/d growth). In the subsequent experiments cassava starch was included in the test diet (21%). In the second experiment the treatments were 0, 10 and 15% replacement of the protein from soya bean meal with ground, oven-dried leaves of Trichanthera gigantea. There were no differences in intake (1.49, 1.43, 1.5 and 1.51 g/hour, respectively) nor in growth rate (0.39, 0.36, 0.45 and 0.36 g/hour). In the third experiment the test protein was derived from Azolla filiculoides included at the same levels as in Experiment 2. There were no differences in intake ( g/d) nor in growth rate (24.6, 29.4, 34.0 g/d).
It is concluded that: (i) leaf meals from Trichanthera gigantea and Azolla filiculoides can replace up to 15% of the protein normally derived from soya bean meal in diets of monogastric animals; (ii) the chick growth assay with protein-free energy sources is an appropriate biological test to assess the nutritional value of potential protein-rich supplements.