It shall be unlawful for any weighman, grader, or auctioneer, licensed in accordance with the provisions of this article, to buy or trade in any livestock or other agricultural and horticultural products, graded, weighed, or auctioned by him either for himself or partnership at any public market in which he is employed, or to misweigh or falsely report any weights or otherwise fraudulently manipulate the scales to produce a weight other than the true and actual weight of any livestock, poultry, or other agricultural and horticultural products consigned to and sold at any public market.