Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extracts¹

This study proposes a method of direct and simultaneous determination of the amount of Ca2+ and Mg2+ present in soil extracts using a Calcium Ion-Selective Electrode and by Complexometric Titration (ISE-CT). The results were compared to those obtained by conventional analytical techniques of Complexometric Titration (CT) and Flame Atomic Absorption Spectrometry (FAAS). There were no significant differences in the determination of Ca2+ and Mg2+ in comparison with CT and FAAS, at a 95 % confidence level. Additionally, results of this method were more precise and accurate than of the Interlaboratorial Control (IC)

Nutritional value of some feedstuffs used in the diet of captive capybaras

Five pen-raised adult female capybaras were used in five digestibility trials in a Latin square design, to determine, for capybaras, the nutritional values of Cameroon grass (Pennisetum purpureum cv. Cameroon); Napier grass (P. purpureum cv. Napier); corn grain; cassava hay, comprising leaves and stems; and palm kernel (Elaeis guineensis) cake. These feedstuffs were provided separately or mixed, in a completely randomized manner, in different experimental periods. The digestibility of each feedstuff not supplied alone was estimated by difference. The animals were individually introduced in metabolism pens. Following a 10-day period of adaptation to each diet, feed intake was recorded and total fecal output was collected over five consecutive days. Energy, crude protein and neutral detergent fiber digestibilities of Cameroon grass were, respectively, 0.88 (±0.07, standard deviation), 0.63 (±0.39) and 0.82 (±0.15). For Napier grass they were 0.84 (±0.05), 0.63 (±0.12) and 0.72 (±0.10); for corn grain, 0.92 (±0.05), 0.97 (±0.20) and 0.83 (±0.14); for cassava hay, 0.86 (±0.12), 0.84 (±0.14) and 0.43 (±0.16); and for palm kernel cake 0.94 (±0.05), 0.85 (±0.14), and 0.97 (±0.05). These digestibilities in capybaras were higher than the digestibilities of the same feedstuffs in other livestock. These results can be explained by the anatomical and physiological characteristics of the capybara, which lead to a high rate of nutrient digestion and absorption