Previous work (Blanchard et al, 1995) has suggested that the feeding of a high energy/low protein diet to finishing pigs produces pork of a superior eating quality compared to animals fed conventional energy and protein diets. It has been demonstrated in recent studies (Blanchard et al, 1995) that pork eating quality, particularly tenderness, can be influenced by a change of diet imposed at two weeks prior to slaughter. It has also been suggested (Warkup and Kempster, 1991) that both growth rate and fatness are positively correlated to pork eating quality and that proteolytic enzymes are involved in determining eating quality (Blanchard 1994). The objective of this study was therefore to test these various hypothesis.

Two diets were evaluated: CEP diet (DE 14.0 MJ/kg, Protein 200 g/kg, Lysine 10.0 g/kg) and HELP diet (DE 15.0 MJ/kg, Protein 160 g/kg, Lysine 7.0 g/kg). Treatment 1 animals (n=26) received CEP fed ad libitum 45 kg to 90 kg Iwt. Treatment 2 animals (n=23) received HELP fed ad libitum 45 kg to 90 kg lwt. Treatment 3 animals (n=23) received CEP diet until 14 days prior to slaughter following which they received HELP diet fed ad libitum. A range of carcass and meat quality characteristics were recorded. Grilled loin steaks from each animal were evaluated for eating quality characteristics by trained sensory panel and rated on a scale of 1-8 (increasing with intensity). Activity levels of calpain and calpastatin were measured in samples of LD muscle remove from each carcass 45 minutes after slaughter.