Heavy Metals in Selected Tissues and Organs of Slaughtered Goats from Akinyele Central Abattoir, Ibadan, Nigeria

Abstract

Meat and offal obtained from goat has been widely accepted as delicacy and serve as important source of protein consumed daily by all strata of the society. In contrast, consumers’ knowledge on the possible exposure to heavy metals in meat and its associated health risk in Nigeria is generally low. Therefore, this study aimed at assessing heavy metal levels in selected tissues and organs of slaughtered goats.An exploratory study design with observational and laboratory analysis component was adopted. Lead, cadmium and chromium in blood, muscle, liver and kidney of goat slaughtered in central abattoir, Akinyele, Ibadan were studied. Samples of blood from jugular vein at slaughter, external abdominus muscles, liver apical lobes and kidney cortices were collected. A total of twenty (20) goats were purposively selected over a period of 8 weeks. Samples were analyzed using Atomic Absorption Spectrophotometer (AAS). Statistical analysis was done using descriptive statistics, t-test and ANOVA.Male (60%) and 40% female goats with mean age of 28.8 months were included. Samples (4) comprising of blood, muscle tissue, liver and kidney were taken from each animal totaling 80 samples. Samples were analyzed for lead, chromium and cadmium. In the 80 samples, heavy metal levels found included cadmium in 52 samples (65.0%), lead in 8 samples (10.0%) and chromium in 8 samples (10.0%). Values were compared with Joint FAO/WHO guidelines. Mean chromium residual values in blood, muscle tissue, liver and kidney for the goats were (2.37±2.55, 0.00, 0.62±0.00 and 0.01±0.00 mg/kg). Chromium residue was only higher in the blood. Mean cadmium values in blood, muscle tissue, liver and kidney of goat were (6.75±3.03, 5.43±1.94, 5.51 ±2.92 and 4.77±1.93 mg/kg). These values were generally higher than permissible limit of 0.5-1.0mg/kg. Mean lead residual values in blood, muscle, liver and kidney were within the permissible limits. The goat meat contained levels of cadmium in all tissues sampled while chromium was only found in blood at a level that is above the tolerable limit; hence this could pose health risk to consumers. It is therefore recommended that goat be raised away from environment that is known for cadmium and chromium discharge or emission, so as to reduce their bioaccumulation.

Keywords: Goat, Cadmium, Lead, Chromium, Abattoir