Environmental Impacts of Feeding High-fiber Diet to Pigs

The concentration of volatile fatty acids （VFA） determined from a previous study was used to determine the concentration of carbon dioxide （CO2） and methane （CH4） in pig digesta using the model developed for ruminant animals. Digesta from the stomach, cecum and colon of pigs （n = 3 dietl） were used for the determination of VFA. The pigs were fed either a low fiber diet （LFD; 8.3% aNDF） as control, or one of the high-fiber diets （HFD, 22.4% aNDF; D1, D2 and D3） containing 1：2, 1：1 and 2：1, oats to barley ratios, respectively. Results indicated that the concentrations of CO2 and CH4 in pigs fed HFD were, on the average, 25.8 and 24.2%, respectively lower （P 〈 0.05） than pigs fed LFD. Pigs fed the highest oat to barley ratio also showed higher （P 〈 0.05） levels of CO2, （8.3%） and CH4 （5.1%）, compared to the average of the two lower ratios （CO2, 5.3% and CH4, 3.3%）. Molar proportions of VFA, CO2 and CH4 in the gut were in the order of VFA 〉 CO2 〉 CH4, at 53.0%, 28.6% and 18.4%, respectively, and CO2 and CH4 combined represented 47% of total gas.

Gut Fermentation and Growth Performance of Pigs Fed High Fiber Diet

Ninety six pigs average weight 9.15 kg were used to study the effects of feeding diets containing multiple sources of dietary fiber （DF） on weight gain and concentration of fermentation products in the digestive tract. The experiment employed four diets and four pens diet1. Diets included a low fiber diet （LFD）, as control and three antibiotic free high-fiber diets （HFD） containing a 1：2, 1：1 or 2：1 oats：barley ratios. At the end of the 70 d feeding trial three pigs of comparable weight diefI were slaughtered. Digesta taken from the stomach, cecum and colon were used for the determination of volatile fatty acids （VFA）. Results indicated that inclusion of HFD increased （P 〈 0.05） feed intake but not weight gain. As revealed by the higher feed intake the nutritional value of HFD was approximately 88% of LFD. Also, as the amount of oats in the diet was increased, VFA concentration was also increased while isobutyrate decreased （P 〈 0.05）. Lower concentration of isobutyrate may indicate parallel reduction in other putatively toxic products of protein fermentation in the digestive tract. Thus, inclusion of multiple sources of fiber in the diet impacted feed intake and the products of gut fermentation in growing pigs.

Impacts of High Fiber Diet on Digestion and Absorption of Minerals in Growing Pigs

The study was conducted to investigate the effects of feeding high-fiber diet （HFD） on apparent total tract digestibility （ATTD） and absorption of minerals in growing pigs. Sixteen barrows averaging 16.39 kg were randomly assigned to one of four diets after metabolic crate assignment with individual pig serving as experimental unit. Diets include： a corn-soybean meal based low-fiber diet （LFD）, as the control （CON） and 3 HFD （D1, D2 and D3）, each containing 5% sugar beet pulps and a 1：2, 1：1 and 2：1 oats to barley ratios, respectively, replacing 47% of the corn in the diet. Diets were formulated to meet nutrient requirements, however, the fiber content of the LFD was substantially lower than the average of the HFD （8.38% vs. 22.40%）. Feed allowance was limited to 10% of average body weight and fed twice/d. The study period was divided into 10 d of adjustment and 5 d of feces collection. Data collected were analyzed using SAS, GLIMMIX procedure where animals were considered random effects, and minerals were fixed. Results of the study show that digestibility of Ca in pigs fed HFD was lower （P 〈 0.05） than in pigs fed LFD. On the other hand, the apparent digestibility of P, K, Na, S and Zn in pigs fed D2 and D3 were higher （P 〈 0.05） than in pigs fed CON diet. It was also observed that digestibility of Ca, P, K, Na, S and Zn in pigs fed D1 were lower （P 〈 0.05） than in CON, D2 or D3 fed pigs. Therefore, it was concluded that while feeding HFD reduced availability of Ca, the availability of P, K, Na and S to pigs improved as the oat to barley ratio in the diet increased.