The beneficial effect of dietary zinc supplementation on anaemia and immunosuppression in Trypanosoma brucei infected rats.

Zinc is an essential trace element crucial for normal development and function of cells mediating nonspecific immunity and protects bio-molecules from oxidative damage. This study was designed to assess the effects of dietary zinc supplementation on anaemia and immunity of trypanosome-infected rats. Thirty rats, divided into five groups (A-E) of 6 each, were used for the study. Parameters used to assess the effect of the supplementation are antibody response to Sheep RBC using direct haemagglutination test, parasitaemia using the rapid matching method, WBC count using the improved Neubauer haemocytometer method, haemoglobin concentration using the cynomethaemoglobin technique while PCV was determined using the microhaematocrit method. The pre-infection supplementation did not prolong the pre-patent period significantly (p > 0.05). However, it significantly (p < 0.05) increased the packed cell volume (PCV), haemoglobin (Hb) concentration, leucocyte count, and antibody titre by day 7 on the supplementation (OTS). Following infection on day 7 OTS, the PCV and Hb decreased but remained significantly (p < 0.05) higher than the infected not supplemented (INS) group, while on day 14 OTS, they maintained a significantly (p < 0.05) higher antibody titre as compared to other groups. On day 21 OTS, theweight of 8 ppm and not infected not supplemented (NINS) groups was significantly (p < 0.05) higher but the relative organ weight of their liver and spleen was significantly (p < 0.05) lower than 2 ppm, 4 ppm and INS groups. On day 21 OTS, the parasitaemia levels of INS group was significantly (p < 0.05) higher than the supplemented groups. From the results, dietary zinc supplementation can be useful in the management of anaemia and immunosupression caused by trypanosomes in rats.

Effects of dietary selenium supplementation on parasitemia, anemia and serum proteins of Trypanosoma brucei brucei infected rats.

Trypanosomosis has been associated with immunosuppression, anemia and oxidative damage while selenium possesses both immunostimulatory and antioxidative effects. This study was designed to assess the effect of dietary selenium supplementation on parasitemia, anemia, survival pattern and serum protein profiles of trypanosome-infected rats. Twenty five rats, divided into five groups (A-E) of 5 each, were treated as follows: 4, 8 and 16 ppm (ppm) of selenium in their feed, respectively throughout the experimental period and were infected with Trypanosoma brucei brucei on day 14 post supplementation, infected not supplemented and the negative control. Supplementation at 4 and 8 ppm increased the packed cell volume (PCV) and hemoglobin (Hb) concentration on day 7 of supplementation (PS) when compared with the unsupplemented groups. Following infection on day 14 PS, the PCV, Hb of 16 ppm and infected not supplemented groups were significantly (P < 0.05) lower than other groups on days 28 and 35 PS. Supplementation did not lead to significant (P > 0.05) changes on the total protein, albumin and globulin by day 14 PS. Infection, however, caused significant (P > 0.05) decrease in the total protein and albumin from day 28. The supplementation did not significantly (P > 0.05) increase the pre-patent period but caused a significant reduction in the parasitemia levels and increased survival intervals. Dietary selenium supplementation, from the results, may show promise in the management of African trypanosomosis as the supplementation was able to: reduce anemia and parasitemia and increase survival intervals of trypanosome infected rats.

Resistance and resilience of traditionally managed West African Dwarf goats from the savanna zone of northern Nigeria to naturally acquired trypanosome and gastrointestinal nematode infections.

A survey was conducted of gastrointestinal nematode infections and trypanosomosis in Nigerian West African Dwarf (WAD) goats from the savanna region of the country. Animals were screened at two markets, Gboko and Akpagher, from the beginning of April until the end of September, coinciding with the end of the dry season and the first 5 months of the wet season. Of 1054 goats that were examined, 80.5% carried gastrointestinal (GI) nematodes belonging to the genera Haemonchus (61.0%), Oesophagostomum (21.0%) and Trichostrongylus (17.9%). Faecal egg counts (FEC) increased very slowly but significantly from April to maximum levels in September, and varied marginally between the two market sources. The majority of goats (68.8 and 70.1% at the two markets) had low FEC not exceeding 50 eggs/g (epg). FEC did not differ significantly between the sexes or between age classes. Packed cell volume (PCV) also declined significantly with month of the study, but was affected by host sex (a significant month x sex interaction) being generally higher in male animals throughout the period. There was a highly significant negative correlation between log10(FEC+1) and PCV, when all other factors had been taken into account. Body condition scores (BCS) also declined with month of the study, but there was a marked difference between the two sexes, with male animals generally showing a greater stability of BCS across the months compared with females. Trypanosome infections were found in only 4% of the goats and only during the rainy season. Most infections (92.86%) were caused by Trypanosoma brucei alone although T. vivax and T. congolense were occasionally detected. Overall, the majority of goats sampled each month maintained generally good body condition (BCS 3.0-5.0), normal or slightly reduced PCV, even when concurrently infected with trypanosomes and GI nematodes. However, four concurrently infected goats showed signs of overt anaemia during periods of peak infection, during the late rainy season, with marked reductions in PCV (< 15%). Two of the infected goats were also in poor body condition with BCS of < 2.0. There was no evidence of additive or synergistic pathogenic effects of the two parasites. These results are discussed in the context of the unexpectedly strong resistance and resilience of the savanna WAD ecotype to its native strains of GI nematode and trypanosome parasites.