Lupinus albus cv. Ultra and Lupinus angustifolius cv. Unicrop as protein concentrates for growing pigs

Abstract

Lupinus albus cv. Ultra and Lupinus angustifolius cv. Unicrop were evaluated relative to soybean meal as sole protein concentrates in wheat-based diets for growing pigs. To ensure that this comparison was on an equal protein and lysine basis, small amounts of free lysine were added to the lupin diets. The digestible energy contents of the soybean, Ultra and Unicrop meals were 15.2, 15.0 and 15.3 MJ/kg (air-dry basis) respectively. The performances of pigs fed on diets based on the Unicrop and soybean meals were similar in all parameters, except that the Unicrop diet resulted in a significantly lower dressing percentage (P < 0.01) and a slightly higher feed conversion ratio (P < 0.05) when calculated on a carcass basis. Pigs fed on Ultra lupins showed significantly lower (P < 0.05) growth rates and significantly higher (P < 0.05) feed conversion ratios during the 20–45 kg growth phase; and significantly lower carcass gains (P < 0.01) and higher feed conversion ratios on a carcass basis (P < 0.05) during the 20–80 kg growth phase. The dressing percentage of pigs fed on Ultra lupins was similar to that of those fed on Unicrop lupins and significantly lower than for pigs fed on soybean meal (P < 0.01). The Ultra lupins contained 3750 ppm manganese, and this may have contributed to the depressed performance of pigs on Ultra meal.