Some biochemical changes following Trypanosoma congolense infection in Djallonké ewe lambs and breeding ewes fed on two levels of nutrition

Abstract

The effects of artificial Trypanosoma congolense infection and dietary level on biochemical changes were observed in 24 ewe lambs (Experiment 1) and 42 breeding ewes (Experiment 2). All animals belonged to the Djallonké breed which is known to be trypanotolerant. For both experiments, there were four treatment combinations, of which two were kept on a restricted diet (L), the other two on an at libitum diet (H). Half of each dietary group was infected with T. congolense (LI, HI), while the remainder served as uninfected controls (LC, HC). Artificial T. congolense infection took place at the age of 200±7 days in Experiment 1 and at the peak of oestrus in Experiment 2. Irrespective of dietary levels offered, total proteins in lambs and ewes and albumin in lambs declined significantly ( P<0.001) post infection. Plasma glucose concentration was reduced by the low dietary level and not by infection. Although plasma urea concentrations were slightly increased in the infected ewe lambs, adult ewes in the HI group demonstrated increased plasma urea concentrations ( P<0.05) due to an interaction between infection and diet. Neither infection nor the imposed diet induced significant changes on plasma creatinine concentrations. Transitory peaks in non-esterified fatty acids (NEFA) and beta-hydroxy butyric acid (BHBA) levels in infected ewes on low dietary level indicated temporary changes in the energy metabolism of the host. It was concluded from this study that, inspite of their trypanotolerance, Djallonké lambs and ewes demonstrated an infection effect on host metabolism pattern due to T. congolense infection. These changes reflected to some extent trypanosome-induced alteration of the nutrient metabolism, which could not always be negated by diet supplements. Nutrition, as an independent factor, did confer added benefits against the debilitating effects of trypanosomosis under the conditions of the present study.