Influence of fiber type on enteric methane production from growing-finishing pigs and subsequent biochemical methane potential of excreted feces

Abstract

Three diets differing in type and amount of total fiber (TF) were formulated in order to investigate the effects of fiber type and amount on enteric methane (CH₄) production from growing-finishing pigs and subsequent biochemical CH₄ potential of the excreted feces. The experimental diets consisted of a control diet based on wheat, barley, and soybean meal, a diet with high content of insoluble TF based on wheat bran (WB), and a diet with high content of soluble TF based on sugar beet pulp (SBP). Eighteen female growing-finishing pigs were allocated to one of three experimental diets according to a replicated incomplete 3 * 2 Latin square design. After adaptation to the diet and metabolic cages, urine and feces samples were collected for 4 days, including 48 hours of gas exchange measurements in respiration chambers. Excreted feces were collected when pigs weighed 64.8 ± 3.8 kg and 89.7 ± 4.4 kg to determine the biochemical CH₄ potential (BMP) of the feces in batch experiments. The enteric CH₄ production expressed per TF intake was affected by the type of TF, with the lowest CH₄ production obtained when pigs were fed a WB diet (P < 0.02). However, the decreased methanogenesis in the hindgut of the pigs was counteracted by the increased BMP₉₀ of the feces. On the other hand, although feeding pigs with an SBP diet resulted in the highest enteric CH₄ production, the CH₄ derived from feces also remained high. In conclusion, the fiber type alters the methanogenesis in the hindgut of pigs and the subsequent BMP₉₀ of the feces, and, therefore, needs to be considered during diet formulation in the context of minimizing enteric CH₄ production and maximizing the BMP₉₀ of the feces.