Effect of bacterial protein meal grown on natural gas on growth performance and carcass traits of pigs

Abstract

Bacterial protein meal (BPM), a new protein feedstuff produced by bacteria (Methylococcus capsulatus, Alcaligenes acidovorans, Bacillus brevis and Bacillus firmus) grown on natural gas, was evaluated as a protein source for pigs. Two growth trials were conducted, one with growing-finishing pigs and one with pigs from weaning until slaughter. In Exp. 1, 18 pigs fed restrictively (26.0 and 109.4 kg initial and final weight) were used to determine the effect of dietary inclusion of BPM (0, 60, or 120 g kg-1), replacing protein from soybean meal on growth performance and carcass traits. Adding 60 and 120 g kg-1 BPM to diets reduced (P < 0.01) ADG and feed efficiency during the growing period, but had no effect on growth performance during the finishing or overall periods. Both levels of BPM improved amino acid and lysine utilization (P < 0.01) compared with the control. Fat firmness tended to increase with inclusion of BPM. When using orthogonal contrast, both levels of BPM tended to increase carcass meatiness. In Exp. 2, 48 pigs (11.4 and 107.2 kg initial and final weight) were used to evaluate increasing levels of BPM (0, 50, 100, or 150 g kg –1) on growth performance and carcass traits from weaning at 34.5 days of age until slaughter. Bacterial protein meal reduced ADG (linear P < 0.03) during the period from weaning until five weeks post weaning and during the period from weaning until slaughter. Increasing levels of BPM tended to increase overall feed/gain. Also, BPM increased backfat firmness (linear P < 0.01), but reduced percent carcass lean (linear P < 0.05) and carcass meatiness (linear P < 0.01), and increased P2 backfat thickness and fat area in cutlet (linear P < 0.05). All levels of BPM improved amino acid and lysine utilization (linear P < 0.05) compared with the control. In conclusion, up to 120 g kg –1 BPM in diets for pigs from 26 kg live weight until slaughter had no adverse effect on overall growth performance or carcass lean or fat content. Up to 150 g kg –1 BPM to diets for pigs from weaning until slaughter reduced growth rates during the piglet period and increased carcass fat content due to marginal dietary lysine levels. Bacterial protein meal gave a dose dependent improvement in the utilization of total amino acids and lysine and the quality of back fat determined as fat firmness and fat color.