Comparative evaluation of weaning foods from Glyricidia and Leucaena leaf protein concentrates and some commercial brands in Nigeria

Three studies were conducted to evaluate the nutritive potential of Glyricidia leaf protein concentrate (GLPC) and Leucaena leaf protein concentrate (LLPC) in infant weaning foods. The first two trials evaluated 10 laboratory-formulated weaning foods, in which soybean meal (SBM) was replaced at levels of 0, 25, 50, 75 and 100% with either GLPC or LLPC, and subsequently compared them nutritionally with three commercial weaning foods (coded CFB, CFC and CFN) currently on sale in Nigeria in a 28 day feeding trial using weanling albino rats. Thereafter the best GLPC- and LLPC-based weaning foods, in terms of animal performance consistent with low cost of the foods (designated GL50 and LL25 respectively), were compared with the best commercial weaning food (CFB) in a 14 day rehabilitative potential trial using rats that had previously been protein depleted. In the first trial the final weight was highest in rats fed the 50% GLPC-based food (159.8 ± 9.5 g) and lowest in rats fed CFN (114.7 ± 9.7 g), while the feed efficiency was best in rats fed the 50% GLPC-based food and CFC and worst in rats fed the 100% GLPC-based food and CFN. The nitrogen retention (NR) did not differ significantly (P greater than or equal to 0.05), while the apparent nitrogen digestibility (AND) and 'operative' protein efficiency ratio (PER) decreased with increasing level of replacement of SBM with GLPC (R2 = 0.61, P less than or equal to 0.05 and R2 = 0.67, P less than or equal to 0.05 respectively). In the second trial the highest weight gain was observed in rats fed the 25% LLPC-based food (3.4 ± 0.5 g day-1). Feed consumption was not significantly (P greater than or equal to 0.05) influenced by dietary treatment, but rats fed the laboratory-formulated diets containing 0 and 25% LLPC utilised their food more efficiently (3.0 ± 0.4/0.2 respectively) than rats fed the other diets, including the commercial foods. While NR did not differ significantly (P greater than or equal to 0.05), there was a decrease in AND and PER with increasing level of SBM replacement with LLPC (R2 = 0.96, P less than or equal to 0.01 and R2 = 0.89, P less than or equal to 0.05 respectively). Among all the organs weighed in the first two trials, only the relative weight of the lungs was significantly (P less than or equal to 0.05) affected. Neither the haematological variables nor the serum metabolites were significantly influenced by dietary treatment, except for the packed cell volume of rats fed the LLPC-based foods. The economics of food production showed that all the laboratory-formulated foods were cheaper than the commercial foods, with the 50% SBM + 50% GLPC (GL50) and 75% SBM + 25% LLPC (LL25) formulae proving to be the most nutritious. On rehabilitation, rats fed LL25 recovered lost weight faster than those fed GL50, followed by rats fed the best commercial diet (CFB), while the whole-body and liver protein contents were identical. The incorporation of LPC/SBM mixtures into local food formulae is suggested as a valid intervention strategy for tackling the endemic protein under-nutrition, especially among vulnerable groups, in sub-Saharan Africa.