Replacement of meat and bone meal with whale meal or whale solubles in pig diets and the accumulation of mercury in the carcase

Abstract

The effects of replacing all or part of the protein supplied by meat and bone meal with whale meal or whale solubles were studied in four experiments with growing pigs fed diets based on wheat and barley. The growth rate and feed conversion efficiency of pigs receiving whale meal were equal to those fed meat and bone meal, whereas the performance of pigs fed whale solubles was inferior. Both whale meal and whale solubles contained mercury which accumulated in the tissues of growing pigs. The level of mercury accumulated was related to the dietary concentration and type of whale product, the period of time during which it was fed, and the type of carcase tissue. Whale meal contained more mercury than whale solubles and produced higher concentrations of mercury in the tissues. The levels of mercury in the tissues of pigs at 45 kg liveweight were lower than those of pigs at 80-85 kg liveweight. When the diets included more than 1 per cent whalemeal or 3 per cent whale solubles, the carcases contained more mercury than is tolerated by the health standards.