A Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of
Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of
Science and Technology
Potential of Tanzanian local materials was explored for alleviating aflatoxin-contamination of
feeds. Preliminarily, farmers’ awareness of aflatoxins was assessed using data collected from
a random sample of 258 households in Meru District in Arusha, Tanzania. An in-vitro
experiment, was used to evaluate aflatoxin-binding capacity of test materials (TMs); clays
from Arusha (AC), Kilimanjaro (KC), Coast (CC) and Morogoro (MC) and ash-materials
identified as volcanic ash (VA) and rice-husk ash (RA) in buffered solution. The TMs were
compared for binding capacity with a reference-binder (Mycobind
®
, R). An in-vivo complete
randomized experiment was used to evaluate aflatoxin-binding capacity of the TMs in
reducing bioavailability of dietary aflatoxins using 109 rats in unbalance eight groups. On
basal diet, dietary treatments DAC, DKC, DCC, DMC, DVA, DRA, each containing 2% of
one of the TMs, DR containing 2% of R and DC (control) were formulated. One rat-group
was fed one of the diets. Effects of the diets on feed intake (FI), growth rate (GR), feed
conversion efficiency (FCE), packed-cell-volume (PCV), serum-total protein, albumin,
globulin and albumin/globulin ratio (AGR) and parameters of liver, kidney and spleen of the
rats were assessed. About 52%, 8% and 32% of respondents were aware that fungal toxins
may occur in feeds, be transferred into foods of animal origin and are detoxifiable,
respectively. About 28% of the respondents had ever heard about aflatoxins. Significantly
(p<0.05), ≥secondary education, biological/life science exposure and short-time in livestock
industry, positively influenced farmers’ awareness of aflatoxins. Statistically, in-vitro
aflatoxin-binding capacity of RA (84.7%) or AC (72.6%) was comparable to that of R
(98.1%). Each of TMs could bind >94% of aflatoxin-B1.Statistically, FCE (16.6%) of DKC
and AGR of DVA (1.2) were comparable to that of DR (17.5%, 1.2), respectively. Relative
weight of liver of DRA (3.8%) was statistically normal comparable to that of DR (3.7%).
Only DVA showed normal tissues of liver, kidneys and spleen. Farmer’ awareness of
aflatoxins was low, calling for more sensitization. Based on the in-vitro and in-vivo
experiments, RA seems to be the best aflatoxin-binding material. Further testing of the TMs
using farm animals and their combined performance effect are recommended.