|Yen, Jong Tseng|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 24, 2004
Publication Date: June 1, 2004
Citation: Yen, J. T., Varel, V. H., Nienaber, J. A. 2004. Metabolic and microbial responses in western crossbred and Meishan growing pigs fed a high-fiber diet. Journal of Animal Science. 82:1740-1755. Interpretive Summary: Chinese Meishan pigs were thought to have greater ability in utilizing fibrous diets than western breeds of pigs and might serve as a model for developing innovative approaches to increase use of fibrous by-products in pork production. In the present study, Meishan purebred and Duroc × White composite crossbred growing pigs were fed a high-fiber diet containing 35% dehydrated alfalfa meal, and measurements were conducted for the total tract nutrient digestibility, activity of fecal fiber-degrading bacteria, absorption of volatile fatty acids produced in the gut, and energy expenditure by the portal-drained viscera and by the whole body of pigs. Results of the study showed clearly that Meishan growing pigs were not superior to Duroc × White composite crossbred growing pigs in all measurements of dietary fiber utilization. Under our experimental conditions, there is no advantage in using Meishan growing pigs in the search for enhanced use of fibrous feed ingredients by swine.
Technical Abstract: Four Duroc x White composite crossbred (21.8 ± 1.0 kg) and four Meishan purebred (20.7 ± 1.6 kg) 12-wk old growing barrows were used to determine metabolic and microbial responses to a high-fiber diet. The pigs were trained to consume once daily 700 g of a diet containing 35% dehydrated alfalfa meal. The pig's daily intake of DM, N, GE, NDF and ADF were 610 g, 16.6 g, 2.64 Mcal, 150 g, and 88 g, respectively. On d 12 after surgical catheterization of the portal vein, ileal vein, and carotid artery in the pigs, a 3-d total urine and feces collection was conducted. On d 24 post-surgery, each pig was placed in an open-circuit calorimeter and its catheters were connected to a system for simultaneous measurements of the oxygen consumption by portal-drained viscera and by whole-body, and the net portal absorption of VFA after a 24-h fasting and during a 5-h postprandial period. The VFA measured included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. A second 3-d total urine and feces collection was conducted on d 30 post-surgery. There were no differences (P >/_ 0.13) between the first and second collections in apparent total tract digestibility coefficients for nutrients and N retention of pigs. Compared with crossbred pigs, Meishan pigs had lower (P < 0.05) apparent digestibility coefficients for DM, N, NDF, and hemicellulose, and N retention, but their portal-drained viscera used a greater (P < 0.05) fraction of whole-body oxygen consumption. No differences (P >/_ 0.12) were found between crossbred and Meishan pigs in total viable bacteria and cellulolytic bacteria from fecal samples, in vitro digestibility of alfalfa NDF fractions by fecal inocula, whole-body oxygen consumption, net portal absorption of VFA, total energy of absorbed VFA, and the potential of absorbed VFA for meeting energy needs for whole-body heat production. These results indicate that the ability of Meishan growing pigs to utilize a high-fiber diet is not superior to that of Duroc x White composite crossbred growing pigs.