Nutritional value of chickpea (Cicer arietinum) and pigeonpea (Cajanus cajan) meals for growing pigs and rats. 2. Effect of autoclaving and alkali treatment

Abstract

Four experiments were conducted with rats to investigate the effects of autoclaving and alkali treatment on the growth-promoting ability of pigeonpea meal. In the fifth experiment, the effect of autoclaving pigeonpea meal was evaluated with pigs. With rats, there was a quadratic response (P < 0.05) in growth and feed conversion ratio to autoclaving pigeonpea seed for 15 min at 100-140¦C, with maximum response occurring at c. 124¦C. However, growth rate was still lower and feed conversion ratio higher than those of rats fed soybean meal (P < 0.05). Imbibing pigeonpea seed in alkali and subsequently drying it to original weight did not reduce tannin content but did reduce the trypsin-inhibitor activity from 10.3 to 5.1 units mg-1. Although both alkali treatment and autoclaving of the alkali-treated seed improved the growth and feed conversion ratios of rats, these treatments did not overcome the differences in protein quality between the pigeonpea and soybean meal diets. Autoclaving pigeonpea seed for 15 min at 110, 124 and 140¦C reduced the trypsin-inhibitor activity of the meals from 11.2 to 0.7 units mg-'. Compared to pigs fed on unheated pigeonpea meal, pigs given autoclaved meal had higher (P < 0.05) growth rates and improved feed conversion ratios. These improved growth responses were similar to those produced by soybean meal.