Apparent Digestibility of Minerals from Several Ingredients for Tambaqui, Colossoma macropomum, Juveniles

Based on the importance of tambaqui, Colossoma macropomum, for Latin American aquaculture and the digestibility of minerals for the production of sustainable aquafeeds, we designed a series of trials to determine the apparent digestibility coefficients (ADCs) of phosphorus, calcium, magnesium, manganese, and zinc from six protein sources: soybean meal (SBM), corn gluten meal 60 (CGM60), cottonseed meal 40, fishmeal (FM), poultry byproduct meal (PBM), and meat and bone meal (MBM); four cereal grain products: corn, wheat middlings, broken rice (BR), and rice bran (RB); and dicalcium phosphate (DCP). Considerable variation in the ADCs of minerals was observed among the feed ingredients. In general, CGM60, PBM, and RB tended to show the highest ADC values, while SBM, MBM, DCP, and BR showed the lowest ADC values. ADC-P was markedly lower in animal protein sources and the phosphate source (DCP), while high P digestibility was observed for plant protein sources and cereal grain products. Interestingly, tambaqui seems to be able to digest and absorb minerals from plant ingredients more efficiently than animal proteins and DCP. In light of the correlation between nutrient levels and the ADCs of minerals, physiological mechanisms that regulate mineral uptake, and the nutritional ecology of the species, we hypothesize that tambaqui are able to digest minerals from plant proteins with high efficiency.