Gymnopodium floribundum fodder as a model for the in vivo evaluation of nutraceutical value against Haemonchus contortus.

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 ± 3.44kg 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 6000H. contortus infective larvae (L3). 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 0.2kg/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.