Excessive dietary lead reduces growth performance and increases lead accumulation in pigs

The objective of this study was to investigate the influence of dietary lead (Pb) supplementation and feeding period on growth performance, organ weight, and Pb accumulation in pigs.

In a 56-day feeding experiment, a total of 48 barrows with initial body weight 10.4±0.6 kg were allotted to 2 dietary treatments (0 and 200 mg/kg of supplemental Pb) in a completely randomized design with 6 replicates. Body weight and feed intake were recorded to calculate growth performance. At the end of each 14 day-period (on days 14, 28, 42, and 56), an animal was randomly selected from each pen and slaughtered to collect blood samples, hair samples, left 5th rib, heart, liver, kidneys, lungs, and longissimus dorsi muscle samples.

Average daily gain and average daily feed intake were reduced (p<0.05) by supplemental Pb during the day 42 to 56. Relative kidney weight to body weight was linearly increased with increasing feeding period in pigs fed the Pb-supplemented diet, but not in pigs fed the control diet (p<0.05). The Pb concentrations in hair, left 5th rib, kidneys, and lungs were linearly increased with longer feeding period in pigs fed the Pb-supplemented diet, but not in pigs fed the control diet (p<0.01).

Dietary Pb supplementation caused growth retardation and Pb accumulation in most organs, particularly in hair, bone, and kidneys in a time-dependent manner.