Preileal digestibility of coconut fat and soybean oil in horses and their influence on metabolites of microbial origin of the proximal digestive tract¹⁾

Abstract

Three horses (approximately 190 kg BW) fitted with a permanent fistula at the end of the jejunum were used. To a control diet (1/3 hay, 2/3 mixed feed) one of two fat types (coconut fat or soybean oil) were added at 2 levels resulting in fat intakes of 0.1 g (control diet) to 0.5 or 1 g/kg BW 0.5 d, respectively. Each experimental period consisted of 2 weeks adaptation, 2 days of breath tests (before and hourly after the morning meal) and 5 days sampling of chyme. Crude fat, crude protein, concentrations of organic acids (SCFA, lactic acid), pH, and the minerals calcium, magnesium and phosphorus were determined in the chyme; H2 and CH4 in the expired air. The following results were obtained: 1) Fat feeding significantly (P < 0.01) stimulated (independent of amount or kind of fat) the jejunoileal flow of chyme. 2) Preileal fat digestibility increased significantly (P < 0.01) from 30-38% during the control periods to 73-80% (moderate fat intake) and 82-86% (high fat intake). Differences between the fat sources were not significant. 3) Fat addition resulted dose dependent in a reduction (P < 0.05) of lactic acid as well as SCFA concentrations of chyme (at 5th h postprandial). 4) Fat intake caused a reduction in the H2-concentration of the exhaled air (P < 0.05). Such effect was not found with the CH4-concentration, except the high soybean oil level which tended to reduce the concentration. 5) The addition of fat had no significant effects on preileal net absorption of magnesium and calcium, whilst the net secretion of phosphorus significantly increased (P < 0.01). 6) The preileal protein digestibility (control periods 48-53%) was slightly decreased (P < 0.05), due to the fat inclusion.

Linseed oil supplementation in diet for horses: Effects on palatability and digestibility

“…The inclusion of linseed oil did not influence this parameter by contrast to Meyer et al (1997) and Jansen et al (2002) who observed that fat supplement depressed the protein digestibility. According to Meyer et al (1997), a high fat intake may depress protein apparent digestibility in the small intestine due to a higher endogenous N-flow associated with stimulation of digestive secretions.…”

“…The inclusion of linseed oil did not influence this parameter by contrast to Meyer et al (1997) and Jansen et al (2002) who observed that fat supplement depressed the protein digestibility. According to Meyer et al (1997), a high fat intake may depress protein apparent digestibility in the small intestine due to a higher endogenous N-flow associated with stimulation of digestive secretions. On the other hand and although the fact that in normal conditions the true digestibility of fat approaches 100% (Kronfeld et al, 2004), a high lipid charge in diet may increase lipid levels in the large intestine and, owing to lower caeco-colic microbial growth, decrease faecal output in microbial nitrogen (Jansen et al, 2000).…”

Effects of feeding fat on nutrient digestion in cannulated ponies fed a forage diet

“…Estimates of apparent digestibility of fat by ponies were 42 to 49% for forage and 88 to 94% of supplemented fat and oil [16]. However, Meyer et al [17] and Webb et al [18] reported no effect of diet on fat digestibility when horses were fed similar fat amounts. Digestibility differences in previous studies could be due to overall diet composition, and thus, the use of a forage-based diet was selected for this study and recommendations are made for future studies that similar considerations are made in selection of diet composition.…”

Measurement for Breath Concentration of Hydrogen and Methane in Horses

“…Thus, measurement of breath concentrations of H2 and CH4 is useful in diagnosis of acute abdomen such as ileus or colic because it provides an effective indicator of bacterial growth. However, there have been few reports on H2 and CH4 concentrations in horse [3,6,14] because of the difficulty of measuring breath concentrations of H2 and CH4. Previously, such measurement required a large-scale measuring instrument, and thus too complicated for clinical application [2].…”