Haemonchus contortus, Trichostrongylus colubriformis, humoral immunity, cellular immunity
Objective: Determine the productive and immune response of Blackbelly lambs infected
with gastrointestinal nematodes (GIN) and fed with saccharin.
Design/ methodology/ approach: A total of 18 Blackbelly lambs, with an initial live weight (LW) of 13.9 + 3.2 kg, were randomly assigned to three different treatments (T): T1, anthelmintic treatment + basal diet (CTah); T2, basal diet without anthelmintic treatment (STah); and T3, grazing lambs without anthelmintic treatment (STPS). This experiment followed a completely randomized design with repeated measures over time; mean values were compared using Lsmeans. The parameters evaluated included live weight (LW), fecal egg count per gram (FEC), packed-cell volume (PCV), plasma protein (PP), white blood cell
differential count (LEU), and IgA concentration by ELISA with Haemonchus contortus
and Trichostrongylus colubriformis antigens.
Results: STah and CTah lambs showed higher FEC (885 ± 142) and LW (29.73 ± 5.06
kg). Grazing lambs (STPS) had lower PCV (26.4 ± 0.5%) compared to the STah and
CTah lambs (27.4 to 28.4%) due to the high prevalence of H. contortus. The IgA
concentration in grazing lambs ranged from 20.2 to 24.5% of the positive standard
serum titer. The feedlot lambs (STah and CTah) showed values close to 5%.
Study limitations/ implications: Due to anthelmintic resistance problems, it was
impossible to maintain grazing lambs free of infection; therefore, this group was not
Findings/ conclusions: Saccharin increases sheep resilience and achieves adequate
weight gains in parasitized lambs.