REGULAR ARTICLES Gymnopodium floribundum fodder as a model for the in vivo evaluation of nutraceutical value against Haemonchus contortus F. A. Méndez-Ortiz 1 & C. A. Sandoval-Castro 2 & J. Ventura-Cordero 2 & L. A. Sarmiento-Franco 2 & R. H. Santos-Ricalde 2 & J. F. J. Torres-Acosta 2 Received: 29 November 2018 /Accepted: 20 February 2019 # Springer Nature B.V. 2019 Abstract This study validated a protocol to identify the nutraceutical value of Gymnopodium floribundum (GF) foliage based on its effects on sheep nutrition, production and health and its impact on adult Haemonchus contortus. Thirty animals (17.8 ± 3.44 kg BW) were distributed into five experimental groups (n = 6). Groups T1–T3 received feed including 20%, 30% and 40% GF content, respectively, and group T4 received feed with 0% GF. Groups T1–T4 were all infected with 6000 H. contortus infective larvae (L 3 ). Group T5 included six worm-free lambs fed a diet without GF. Feed intake, dry matter digestibility (DMD) and organic matter digestibility (OMD) were measured, in addition to the faecal excretion of eggs per gram (EPG) and total faecal egg count (TFEC) of H. contortus. On day 39 post-infection, lambs were humanely slaughtered to recover and count adult parasites and assess the length and fecundity of female worms. Higher levels of GF in the diet reduced DMD and OMD (P < 0.05), with the lowest values in T3 (40% GF) (P < 0.05). Body weight gain was similar for all groups (0.18 to 0.2 kg/day; P > 0.05). EPG and TFEC were lower in T1 and T3 than in T4 (P <0.05), and the number of adult female worms was lowest in T3 (P < 0.05). In conclusion, GF leaf meal can be considered a nutraceutical when included at 40% (T3) in the diet of lambs, based on its ability to decrease the EPG and TFEC of H. contortus by reducing the female worm burden. A 40% inclusion level had no negative impact on lamb diet intake, production and health, although a reduction of digestibility was observed. Keywords Digestibility . Nutraceutical . Gymnopodium floribundum . Haemonchus contortus Introduction Recent feeding behaviour studies have shown that sheep grazing tropical deciduous forests (TDFs) consume vari- able amounts of foliage from a variety of plant species. The nutritional quality and secondary compound (SC) con- tent of this foliage vary depending on the species (González-Pech et al. 2015). Several plants from TDFs have potential as nutraceutics (Torres-Acosta et al. 2016). Among the plant species consumed by sheep grazing TDFs, Gymnopodium floribundum has a high fibre content and a crude protein (CP) content of ~ 9%, resulting in low digestibility and energy content (Ventura-Cordero et al. 2019). Furthermore, G. floribundum contains high levels of condensed tannins (CTs) (c. 30%). A recent in vitro study showed that G. floribundum leaf extracts inhibited the development of eggs and the exsheathment of infective larvae of the abomasal parasite Haemonchus contortus; these effects were associated with the CT content of the extract (Castañeda-Ramírez et al. 2017). The foliage of G. floribundum is therefore an interesting candidate for in vivo nutraceutical evaluation as it is readily consumed by sheep, provides nutrients and contains SC with in vitro AH activity against GIN. However, it is unknown whether the consumption of G. floribundum foliage by sheep can provoke an in vivo anthelmintic (AH) activity against its gastrointestinal nematode (GIN) populations. In the ab- sence of a harmonization protocol for determining the nu- traceutical value of bioactive plants against GIN, Hoste et al. (2015) proposed the following criteria: (i) the plant * J. F. J. Torres-Acosta tacosta@correo.uady.mx 1 Escuela Superior de Ciencias Agropecuarias, Universidad Autónoma de Campeche, Calle 53 S/N, Col. Unidad, Esfuerzo y Trabajo #2, C.P. 24350 Escárcega, Campeche, México 2 Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, 97315 Mérida, Yucatán, México Tropical Animal Health and Production https://doi.org/10.1007/s11250-019-01855-9