Effect of different diets on growth and survival of Greater rhea (Rhea americana) chicks

BAZZANO G,; NAVARRO J.L.; MARTELLA M.B.

European Poultry Science.

Verlag Eugen Ulmer, Stuttgart

Año: 2007 p. 117 - 121

0003-9098

Commercial breeding of Greater rhea (Rhea americana) isan alternative production activity of comparatively recentdevelopment, chick survival rate being one of the mainproblems encountered (NAVARRO and MARTELLA, 2002).One of the factors that may influence significantly chicksurvival is their nutritional status. Several studies havebeen conducted on nutrition in other ratites, mainly ostriches(Struthio camelus) (FLIEG, 1973; ANGEL, 1996; ULLREYand ALLEN, 1996; AGANGA et al., 2003; COOPER, 2004),which have provided a basis for Greater rhea management.However, information on specific nutrition requirementsof Greater rheas is limited, and no sound feeding managementstrategies have been adopted yet. Most of the producersuse pastures (Medicago sativa, Cichorium intybus, etc.)together with processed feed for chicken, although a processedfeed for rheas is available in the market. But it is notwidely used because of its comparatively high cost. Furthermore,this processed feed has not even been formulatedon the basis of nutritional studies for the species, but theinformation used has been extrapolated from other ratites.Therefore, there is a need to conduct studies to evaluatethe effect of alternative diets – easily available to producers– on chicks' survival and growth.Accordingly, soybean might represent a good dietarysupplement because of its great nutritional value and highcontent of unsaturated fatty acids, mainly linoleic and linolenicacids (MAESTRI et al., 1998), which are essential forbirds since they can only be obtained through food (BLESBOISet al., 2004). Soybean is also an excellent source of energyand proteins for poultry (LÁZARO et al., 2002). COOPERand BENSON, (2000) and COOPER, (2004) indicate thatheat-processed soybean provides high lipid and proteincontent, which may improve the amino acid balance in thediet of ostriches. These authors recommend incorporatingsoybean in the diet of ostriches, although care should betaken to avoid fat excess in the ration. Hence, a supplementof soybean may be capable of improving survival andgrowth of Greater rhea chicks. Furthermore, soybean iswidely used in poultry feeding (MONTY and ALLEE, 2003),which makes it accessible and easily available to producers.However, soybean has antinutritional factors, some ofwhich –those of proteic nature that inhibit pancreatictrypsin – are particularly relevant. Adequate chemical treatmentsor heating can inactivate or destroy those antinutritionalfactors; hence, deactivated soybean should not poseany risk to the birds fed on it (GIORDA and BAIGORRI, 1997).VITANCURT and LEITES, (1999), NAVARRO et al., (2000),VIGNOLO et al., (2001) and NAVARRO et al., (2005) have describedgrowth of captive-bred rheas, but none of theseworks have developed complete growth curves that allowus to compare results on growth of chicks fed on differentdiets. In this work survival was evaluated and completeGompertz growth curves were compared for captive-bredGreater rhea chicks fed on two different types of processedfeed commonly used in rhea farms, either alone or supplementedwith soybean.