Apparent Precaecal Digestibility of Nutrients and Level of Endogenous Nitrogen in Digesta of the Small Intestine of Growing Pigs as Affected by Various Digesta Viscosities

Abstract

Sixteen male growing pigs of about 24 kg BW were fitted with both a duodenal re-entrant and a post-valve T-shaped cannula inserted in the caecum. The animals were divided into four groups. Each group received one of the following diets: corn starch-soybean protein isolate-based diet without (diet C) and with carboxymethylcellulose (diet CMC) or a rye-wheat-based diet without (diet RW) and with xylanase addition (diet RWX). The diets provided similar levels of apparent precaecal digestible crude protein (CP), lysine, methionine + cystine, threonine and tryptophan. Additionally, [15N]-yeast was given with the diets during the first 10 days of the experiment. For estimation of digesta viscosity, N-flow of dietary and endogenous origin, apparent precaecal digestibilities of dry matter (DM), CP, amino acids and non starch polysaccharides (NSP) (only in pigs fed diets RW and RWX), ileal and duodenal digesta were quantitatively collected on day 16 and 17, respectively. The endogenous N-proportion was measured by the ratio of 15N enrichment in the digesta and urine. The duodenal and ileal digesta supernatant viscosity increased as carboxymethylcellulose was included into the diet. Xylanase addition to the rye-wheat based diet reduced the viscosity in the ileal digesta. There were no differences in precaecal digestibilities of DM, CP and amino acids between diet C and CMC. The precaecal digestibilities of DM and soluble and insoluble NSP increased from 69.5% to 73.9%, from 1.3% to 47.9% and from 17.0% to 35.4%, respectively, as xylanase was added to the rye-wheat-based diet. The apparent precaecal digestibility of most essential amino acids increased by 2 to 5 percent units. The amounts of endogenous N at the duodenal level were estimated to be 158, 233, 313 and 276 mg per 12 h per kg0.75 BW of pigs fed diets C, CMC, RW and RWX, respectively. The corresponding values at the ileal level were 95, 107, 164 and 150 mg per 12 h per kg0.75 BW. For endogenous N amounts, significant differences were observed between diets C and CMC (duodenum) and also between semi-purified and cereal-based diets (duodenum and ileum). Methodological aspects for the estimation of endogenous N using the isotope dilution technique are discussed. Obviously, the digesta viscosity per se does not affect the nutrient absorption and endogenous N flow within the small intestine of pigs. Other properties of complex dietary fibre, digesta passage rate or bacterial activity probably contribute to the observed changes.

The effects of pectin and rye on amino acid ileal digestibility, threonine metabolism, nitrogen retention, and morphology of the small intestine in young pigs

“…Also in our experiment the considerable decrease of ileal protein digestibility at the lower P supplement was accompanied by an only minor increase of digesta viscosity and, in contrast, the high digesta viscosity induced by the greater amount of P was accompanied by a relatively small decrease of digestibility. This discrepancy between the effects of P on viscosity and ileal digestibility seems to confirm the assumption that the negative effect of P on ileal digestibility is also related to other factors, such as increased endogenous nitrogen losses and microbial fermentation in the gut (Schulze et al, 1995;McCullough et al, 1998) as well as digesta passage rate (Bartelt et al, 2002), which contribute to changes in the digestibility of nutrients, their absorption, and utilization.…”

“…Insoluble NSP reduce the transit time of digesta and are slowly degradable by the microflora in the large intestine (Buraczewska, 2001;Wenk, 2001). The study of Bartelt et al (2002) showed that not only the viscosity-enhancing property of soluble NSP, but also other properties of complex dietary fibre, influencing digesta passage rate or bacterial activity, may contribute to changes in intestinal morphology, nutrient absorption, and endogenous nitrogen losses.…”

The effect of pectin on amino acid digestibility and digesta viscosity, motility and morphology of the small intestine, and on N-balance and performance of young pigs

“…Schulze et al (1995) found that fibre induced higher ileal N flow and that this increase was composed of 59% endogenous and 41% indigested dietary N. The results of our previous study (Bartelt et al, 2002) suggest that probably not only digesta viscosity (in this study increased up to 88 mPa s) but also other properties of complex dietary fibre, digesta passage rate, or bacterial activity contribute to changes in nutrient digestibility, absorption an utilization. The results of Zhu et al (2005) confirmed increased ileal endogenous N losses in pigs fed increased dietary pectin.…”

“…Chromic oxide was used as a marker. The supernatant viscosity of digesta, amino acids and chromic oxide were determined according to the methods used by Bartelt et al (2002).…”

Metodologias de avaliação do valor nutricional do farelo de arroz desengordurado para suínos

“…Esses PNA aumentam a viscosidade da digesta, formam complexos com as enzimas endógenas e encapsulam os componentes nutricionais digestíveis (Bedford, 2000;Kim et al, 2005). Os arabinoxilanos também podem aumentar as perdas endógenas de N por promover o crescimento de microrganismos no intestino delgado, o que reduz a digestibilidade aparente da proteína (Bartelt et al, 2002).…”