In vitro Evaluation of the Nutraceutical Potential of Theobroma cacao pod Husk and Leaf Extracts for Small Ruminants.

Purpose: Some agroindustrial by-products could be used as nutraceutical materials for small ruminants helping with their nutrition while controlling their gastrointestinal nematodes. This study evaluated the potential in vitro nutraceutical value of pod husks and leaves of three varieties of Theobroma cacao using two Haemonchus contortus isolates with different polyphenol susceptibility.
Methods: Leaves and husks from three T. cacao varieties (AZT, CAL and CEY) were evaluated for their bromatological composition, in vitro dry matter digestibility and polyphenol content. Acetone:water extracts (70:30) of each plant variety were evaluated using the egg hatch and larval exsheathment inhibition tests, using two isolates (FESC and PARAISO) of H. contortus. Effective concentrations 50% (EC ₅₀ ) were determined for both tests. The role of polyphenols was confirmed using polyvinylpolypyrrolidone. L ₃ exposed to CAL leaf extract were submitted to transmission electron microscopy.
Results: Both plant materials showed a good nutritional value to complement protein-rich diets for small ruminants. Extracts inhibited exsheathment of H. contortus L ₃ more effectively than the egg hatching, and the leaf extracts were more active than husk extracts in the L ₃ exsheathment inhibition. The FESC isolate was more sensitive to extracts. Polyphenols blocked exsheathment inhibition of leaf extracts. Structural damage was observed in the sheath and muscles of L ₃ exposed to CAL leaf extracts.
Conclusion: The two T. cacao materials tested showed their potential to be used as ruminant feeds. Extracts affected H. contortus by blocking L ₃ exsheathment, particularly with the leaf extracts. The in vivo nutraceutical value should be confirmed in small ruminants.
(© 2021. Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)