Animal Research International

1431 – 1438

Authors: IKELE, Chika Bright, MGBENKA, Bernard Obialo and OLUAH, Ndubuisi Stanley

The acute toxicity of diethyl phthalate to Clarias gariepinus fingerlings was investigated using static bioassays with continuous aeration for 96 h. The LD50 of DEP for Clarias gariepinus was determined at 95% confidence limit for log toxicant concentration after 24 h, 48 h, 72 h, and 96 h. The LD50 after 24 h, 48 h, 72 h, and 96 h were 2.22, 2.73, 3.44 and 3.93 μg/L, respectively. The LD50 for total death was estimated as 1.87 μg/L. During the exposure period, the test fish was restless, swam erratically and hemorrhaging of the gill filaments was evident. These observations are indicative of stress due to the effect of the diethyl phthalate on the fish. Subacute Diethyl phthalate concentrations (30 μg/L, 40 μg/L, 60 μg/L, and 80 μg/L) were obtained from the LC 50 of the acute study and the fish were exposed to the graded concentrations for 30 days. The fish were killed at 15-day intervals and the liver and kidney were excised and the histopathological changes of DEP on the liver and kidney were determined by light microscopy. Pyknotic nuclei, destruction or fusion of tubules, condensation of the glomeruli, and severe destruction of the tubule were observed in the kidney tissue of fish. Cellular proliferation, congestion, necrosis, sinusoid enlargement, parenchymatous degeneration, and fatty or glycogen degeneration were observed in the liver tissue of fish. The morphological changes of the tissues were dosage-dependent.

1445 – 1451

Authors: Nwosu, O. K. and Nwosu, N. G.

Available evidence shows that there are abnormalities in the metabolism of several trace elements in diabetes mellitus which may have contributed to the pathogenesis and progression of the disease. This study is aimed at investigating the levels of selected trace metals (zinc, copper, calcium, magnesium and lead) in the serum of type I and II diabetes mellitus patients. Thirty non-insulin-dependent diabetes mellitus (NIDDM), 30 insulin-dependent diabetes mellitus (IDDM) and 30 apparently healthy non-diabetic control subjects participated in the study. After an overnight fast, blood samples of all the subjects were collected and the serum concentrations of glucose and these trace elements were measured. Fasting blood sugar (FBS) was determined by glucose oxidase method to confirm the status of the patients and controls while the levels of the trace metals were measured by atomic absorption spectrophotometer (AAS). The mean levels of FBS for the diabetic patients were significantly higher (P<0.05) than those of the control group. Similarly, the mean serum concentrations of copper and lead were significantly higher (P<0.05) in the diabetic patients as compared to the controls. However, the mean values for zinc, calcium and magnesium were significantly lower (P<0.05) in the sera of diabetic patients when compared with the controls. These findings suggest that the altered metabolism of these elements may play a role in the development, pathogenesis and progression of diabetes mellitus.

1458 – 1466

Authors: NNADI, P. A. and ONYEYILI, P. A.

Thirty-six weaner Wistar rats were used to study the effect of protein nutrition on trypanosome isometamidium chloride prophylaxis. Two groups of rats A and B (n = 18 per group) were maintained on a 21% and 14.5% crude protein diet respectively for the twenty-eight days. Thereafter, group A was sub-divided into groups A1, A2, and A3 (n = 9) and group B into B1, B2 and B3 (n = 9) respectively. Concurrently, groups A2 and B2 were given isometamidium chloride at the dose of 1mg\ kg body weight intramuscularly. Fourteen days later, groups A1, A2, and B1, B2 were inoculated with 105 of a low virulent strain of Trypanosoma congolense organisms. Seven days later (before patency), the same groups were re-infected with 106 Trypanosoma brucei brucei organisms. Groups A3 and B3 were left as uninfected controls. Prepatent period and parasitaemia were determined using standard techniques. Also, rectal temperature and Packed Cell Volume (PCV) were determined using standard methods. Data collected were arranged according to days of activity and group means and standard deviation determined. Comparisons between groups for the investigation were done using one-way analysis of variance (ANOVA). There were inconsistent fluctuations in body temperature among all the groups. However, there was a positive correlation between treatment and nutrition on body temperature. The infections caused a significant and progressive reduction in PCV (p<0.05). Isometamidium treatment appeared to protect against reduction in PCV as well as the parasitaemia profile. Generally, the HPD group first appeared more vulnerable but as the infection became chronic, more serious pathology was observed among the untreated LPD group. Within the limits of our design, there were interactions between the drug and nutrition in the pathogenesis and pathology of T. brucei brucei infection.

1473 – 1479

Authors: ONWUBIKO, Henry Amaechi

The transmissible spongiform encephalopathies (TSEs) are characterized by the conversion of the normal cellular prion protein to its abnormal pathogenic isoform which has an increased beta-sheet structure, an increased absorbance at the 700nm region, and an enhanced capacity to form amyloids. Investigation on metal-induced structural perturbation in selected prion protein peptides from hamsters, mice, and humans had residues of 23 – 231, 23 – 144, 23 – 106, and 90 – 231 in non-fibrilar versus amyloid isoforms analyzed with UV-visible scanning and Fourier transform infrared spectroscopy. The proteinase K-resistant amyloid fragment (residues 90 – 231) exhibited a markedly high, broad absorbance at the 700nm region and an increase in beta-sheet character. The addition of copper to the corresponding non-fibrillar 90 – 231 peptides also markedly increased the absorbance of this segment at the 700nm region, and led to an infrared shifted reflecting an increase in beta-sheet secondary structure similar to that of the amyloid. The copper-prompted increase in beta-sheet structure and induced enhancement of the absorbance at the 70nm region when added to the monomeric isoform similar to the amyloid suggest the importance of this structure in the determination of amyloid nucleation, stabilization, formation and perhaps prion infectivity.