Digestion of carbohydrates and utilization of energy in sows fed diets with contrasting levels and physicochemical properties of dietary fiber

¹ Department of Animal Health, Welfare and Nutrition, Aarhus University, Faculty of Agricultural Sciences, P.O. Box 50, DK-8830 Tjele, Denmark

^* To whom correspondence should be addressed. E-mail: anja.serena{at}agrsci.dk.

	Abstract

Three experimental diets were used to investigate the digestion of carbohydrates and utilization of energy in sows fed diets with different levels and physico-chemical properties of dietary fiber (DF). The low fiber diet (LF; DF, 16 %; soluble DF, 4.8 %) was based on wheat and barley. The high fiber 1 diet (HF1; DF, 41 %; soluble-DF, 11 %) was based on wheat and barley supplemented with the co-products: sugar beet pulp, potato pulp, and pectin residue, and the high fiber 2 diet (HF2; DF, 44 %; soluble-DF, 7.3 %) was based on wheat and barley supplemented with approximately one-third of the co-products used in diet HF1 and two-third of brewer's spent grain, seed residue, and pea hull (1:1:1, respectively). The diets were studied in 2 series of experiments. In Exp. 1, the digestibility and ileal and fecal flow of nutrients in 6 ileal cannulated sows placed in metabolic cages designed as a repeated 3 x 3 Latin square design was studied. In Exp. 2, energy metabolism using 6 sows designed as a repeated 3 x 3 Latin square design was measured in respiration chambers. The DF level influence the ileal flow of most nutrients in particular carbohydrates, which increased from 190 g/d when feeding the low DF diet to 538 to 539 g/d when feeding the 2 high-DF diets. This was also reflected in the digestibility of OM and carbohydrates (P < 0.05). The ranking of total excretion of fecal materials was HF2 > > HF1 > LF, which also was reflected in the digestibility of OM, protein and carbohydrates. Feeding high DF diets resulted in greater CH₄ production, which was related to the amount of carbohydrates (r = 0.79) and OM (r = 0.72) fermented in the large intestine, but with no difference in heat production (12.2 to 13.1 MJ/kg DM). Retained energy (MJ/kg DM) was decreased when feeding HF1 than LF and negative when feeding HF2. Feeding sows HF1 reduced the animals' activity (5.1 h/24h) comparing with LF (6.1 h/ 24h; P = 0.045).

Key Words: co-products, carbohydrates, digestibility, energy metabolism, sows, T-cannula