Resumen:
Twenty Katahdin×Pelibuey crossbreed male lambs, 3 to 4 months of age and 24±0.3 kg of body weight, were used to study the anthelmintic effects of administering extracts of Salix babylonica L. (SB) and Leucaena leucocephala Lam. (LL). Lambs had not been treated with anthelmintics previously and were randomly allocated into four groups of five lambs each in a completely randomized design. Treatments were as follows: control (lambs fed on total mixed ration without extracts), SB (as control plus S. babylonica L. extract at 30 ml/day), LL (as control plus L. leucocephala Lam. extract at 30 ml/day), and SBLL (as control plus 30 ml/day of S. babylonica L. and L. leucocephala Lam. extracts in a 1:1 (v/v) mixture) for 63 days. Extracts were orally administered before the 8:00 a.m. feeding to each lamb. Rectal fecal samples were collected from each lamb at day 22 (P1), day 43 (P2), and day 63 (P3) of the experiment. Adult worm and egg counts were determined in each fecal sample immediately after collection. Plant secondary metabolites of total phenolics, saponins, and the aqueous fraction were 50 % lower in the SB versus LL extracts. Overall, the oral administration of extracts has improved the egg and worm count reductions in lamb feces by 54, 47, and 40 % for LL, SB, and SBLL, respectively, versus the control lambs. Reductions of worm egg counts in lamb feces were higher (P <0.05) in P2 and P3 versus P1. Extracts of SB and LL or possibly isolated bioactive compounds could be a promising alternative to conventional anthelmintics to treat gastrointestinal parasites of small ruminants. Such treatments could be used in control strategies against gastrointestinal nematodes in organic and conventional production systems.
Descripción:
In Mexico, small ruminant production has important social and economic functions, especially for small rural farmers who rely on these animals as a source of food and income. Production efficiency of ruminants has been limited by nutritional and sanitary problems with helminth infections being one of the major health conditions affecting humans and livestock. Exposure to nematode parasites depends on the husbandry system under which livestock are raised. In situations where Mexican farmers are almost entirely dependent on grazing, exposure to nematode larvae is continuous throughout the year. Gastrointestinal nematode parasitism is a major cause of sheep and goat mortality in tropical Mexico (Canul-Ku et al. 2012) and other tropical countries (Carvalho et al. 2012). The impacts of gastrointestinal nematode parasitism in practical systems has stimulated research into alternative medications, such as medicinal plants or tree leaf extracts, which are used in ruminants, donkeys, camels, and humans (Wabo-Pone et al. 2009; Carvalho et al. 2012).