Ileal digestibility of amino acids of cassava, sweet potato, cocoyam and erythrina foliages fed to growing pigs

Abstract

Ileal digestibility in growing pigs fed starch-based diets with inclusion of four tropical leaves in a meal form was studied in a 5 3 5 Latin square design. Five diets were formulated with only casein as protein source in the basal diet (CAS), and casein plus dry cassava (CA) leaves, casein plus dry sweet potato (SP) leaves, casein plus dry cocoyam (CO) leaves and casein plus erythrina (ER) leaves in the other four diets. All diets contained the same amount of CP (14%), either provided by only CAS or a combination of casein and 250 g of leaf meal per kg of diet in the other diets. Leaves were separated manually from stems, and only the leaf part was used. A protein-free diet was fed during a sixth period in order to estimate the endogenous protein losses and calculate the CP-and amino-acid (AA)-standardized ileal digestibility (SID) values. The values for the foliages were calculated according to the difference method, assuming no interaction between the foliage and the casein. The ileal tract apparent digestibility of CP, organic matter and energy was higher in diet CAS than in the other diets (P , 0.05). The SID of CP and AA was close to 0.950 for casein, whereas the SID of AA was markedly lower in the foliages; the SID of indispensable and dispensable AA was highest in CO (0.500 and 0.352) and lowest in ER (0.170 and 0.195); intermediate values were obtained for SPs (0.367 and 0.349) and CA (0.232 and 0.242) leaves. Accordingly, the SID of lysine was highest (0.538) for CO leaves and lowest (0.126) in ER leaves; intermediate values were measured for CA and SP leaves. These low SID values in foliage meals must be related to the high levels of dietary fibre and the presence of secondary metabolites (tannins). These results suggest that it is only possible to replace a fraction of the conventional protein sources such as soyabean meal by tropical foliages in growing pig diets with a preference for CO leaves.

Potential use of byproducts from cultivation and processing of sweet potatoes

“…A recent research on pigs, which compared ileal digestibility of amino acids using a diet comprised of 25% fresh sweet potato leaves versus a control diet with casein as the only protein source, concluded that sweet potato leaves could only replace a fraction of the protein typically derived from a more expensive plant-based source, such as soybeans, because of high fiber content and the presence of compounds that decreased amino acid digestibility. However, sweet potato leaves are still potentially quite useful as a protein-supplement for pigs in the tropics where there is a close association between local feed sources, local crops, and animals-small-scale, mixed-farming systems (REGNIER et al, 2012;REGNIER et al, 2013). Nguyen reported that ensiling the leaves resulted in a higher digestibility of nutrients compared to drying the leaves (NGUYEN et al, 2012).…”

Aliments protéiques dans les systèmes mixtes intégrés polyculture-élevage en régions tropicales

“…Les fanes de cultures énergétiques duales Ce sont des coproduits fibreux de certains fruits et tubercules amylacés disponibles après leur récolte et/ ou prélevés tout au long du cycle de végétation. Ils sont principalement consommés par les ruminants mais des travaux récents ont été consacrés à leur évaluation pour l'alimentation du porc (Kambashi et al, 2014 ;Régnier et al, 2012Régnier et al, , 2013Leterme et al, 2005Leterme et al, , 2012, (cf. encadré 1 qui résume les principes d'utilisation de ces ressources pour le porc).…”

Effect of graded levels of fiber from alfalfa meal on apparent and standardized ileal digestibility of amino acids of growing pigs

“…Over two 10-day periods, 6 pigs received a nitrogen-free diet in order to determine endogenous AA losses. The nitrogen-free diet was fed only at the end of the experiment in order to overcome the possible consequences of feeding a nitrogen-free feed on subsequent health and metabolism (Ré gnier et al 2012). At the conclusion of each sampling time, samples were thawed and mixed by individual animal, and a subsample was collected for chemical analysis.…”