Influence of dietary beetpulp on the plasma level of triacylglycerols in horses.

In a cross-over study with six adult horses, the effect of isoenergetic replacement of dietary glucose by beetpulp on the concentration of plasma triacylglycerols was studied. The test ration contained 25% beetpulp in the dietary dry matter. The feeding of beet pulp lowered plasma triacylglycerol concentrations (p = 0.058) in the fasting state and raised the activity of heparin-released lipoprotein lipase (LPL) (p = 0.059) and the concentration of HDL2 cholesterol (p = 0.058). In the fasting state, the plasma concentrations of free fatty acids (p = 0.073) and those of beta-hydroxybutyrate (p = 0.043) were increased after feeding beetpulp. At 3 h after feed intake, consumption of beetpulp instead of glucose had produced higher plasma concentrations of both glucose (p = 0.014) and insulin (p = 0.040). It is suggested that beetpulp ingestion activates LPL followed by a drop in plasma triacylglycerols.

Production and clearance of plasma triacylglycerols in ponies fed diets containing either medium-chain triacylglycerols or soya bean oil.

The hypothesis was tested that feeding ponies a diet containing medium-chain triacylglcyerols (MCT) instead of soya bean oil causes an increase in the production of plasma triacylglycerols, which, under steady-state conditions, is associated with an increased clearance of triacylglycerols. Six ponies were fed rations containing either MCT or an isoenergetic amount of soya bean oil according to a cross-over design. The concentration of MCT in the total dietary dry matter was about 13%. When the ponies were fed the diets for 3 weeks, plasma triacylglycerol concentrations were 0.42 +/- 0.09 and 0.17 +/- 0.03 mmol/l (mean +/- SE, n = 6; p < 0.05) for the MCT and soya bean-oil treatment, respectively. Plasma triacylglycerol production was assessed using the Triton method and clearance with the use of Intralipid(R) infusion. Plasma triacylglycerol production was 2.91 +/- 0.88 and 0.50 +/- 0.14 micromol/l.min (means +/- SE, n = 4; p < 0.05) for the diets containing MCT and soya bean oil, respectively. It is suggested that the calculated rates of triacylglycerol production are underestimated, the deviation being greatest when the ponies were fed the ration of soya bean oil. Triacylglycerol clearance rates were calculated on the basis of group mean values for both the fractional clearance rate and the baseline levels of plasma triacylglycerols; the values were 4.28 and 3.52 micromol/l.min for MCT and soya bean oil feeding, respectively. The mean, absolute clearance rates as based on those found in individual ponies did not show an increase when the diet with MCT was fed. Nevertheless, it is concluded that the data obtained support our hypothesis.

The plasma level of triacylglycerols in horses fed high-fat diets containing either soybean oil or palm oil.

The influence of dietary soybean oil versus palm oil on the plasma level of triacylglycerols was determined in a crossover experiment with four horses. Based on published data for humans and laboratory animals it was expected that a diet rich in unsaturated fatty acids in the form of soybean oil compared to saturated fatty acids in the form of palm oil would lower the plasma triacylglycerol level. The feeding of soybean oil versus palm oil for a period of four weeks did not change the level of plasma triacylglycerols in horses. Mean levels of triacylglycerol, free fatty acids and 3-hydroxybutyrate were 0.17 (SE, 0.04), 0.44 (SE, 0.063) and 0.16 (SE, 0.008) mmol/l, respectively. The fatty acid composition of the plasma triacylglycerols reflected the fatty acid composition of the diets. The activity of lipoprotein lipase was not different between the treatments. It is concluded that, under the present experimental conditions, the feeding of soybean oil to horses does not affect triacylglycerol secretion into plasma and thus does not influence the concentration of plasma triacylgycerols, when compared to the feeding of palm oil.

Apparent digestibility of crude fibre in ponies fed either a low or high-protein diet.

The question addressed was whether apparent crude fibre digestibility in ponies would change after lowering protein intake from adequate to borderline deficient. Four adult ponies were fed a low- and high-protein diet according to a cross-over design. The diets consisted of grass hay and concentrates and provided either 1.5 or 3.6 g digestible crude protein/kg(0.75) per day. The two whole rations provided 2.4 g crude fibre/kg body weight per day. Apparent crude fibre digestibility was not affected by protein intake (low-protein diet: 42.9 +/- 4.03%; high-protein diet: 38.1 +/- 1.14%, means +/- SE, n=4). The low-protein diet caused a significant increase in the ratio of faecal: urinary nitrogen. It is suggested that, when the low-protein diet was fed, sufficient urea flew from the blood into the intestine and ammonia released in the hindgut was conserved so that microbial growth, and thus fibre fermentation, was maintained.

The concentration of plasma triacylglycerols in horses fed diets containing either medium chain triacylglycerols or an isoenergetic amount of starch or cellulose.

In a Latin square design, six horses were fed hay and concentrates with isoenergetic amounts of either starch, cellulose or medium chain triacylglycerols (MCT). The dietary variables provided on average 22% of total dietary net energy. Plasma triacylglycerols and other variables of lipid metabolism were determined. The experimental periods lasted 21 days. Blood samples were taken just before the morning meal and three and six hours later. The diet rich in MCT significantly raised the plasma level of triacylglycerols when compared to either the starch- or cellulose-rich diet. The plasma concentrations of 3-hydroxybutyrate, total cholesterol and phospholipids were significantly higher when the horses were fed the ration with MCT instead of either cellulose or starch. Postprandial insulin concentrations were lowest for the MCT diet, and concentrations of free fatty acids were highest. Lipoprotein lipase activity was not significantly different for the three diets. Our study does not support the idea that cellulose feeding generates sufficient acetic acid in the caecum and colon, so that it would enhance the provision of cytosolic acetyl-CoA which in turn would stimulate hepatic fatty acid synthesis and then raise plasma triacylglycerols.

A preliminary report on a fat-free diet formula for nasogastric enteral administration as treatment for hyperlipaemia in ponies.

A fat-free liquid diet was formulated to be administered by nasogastric tube as therapy for hyperlipaemia in ponies. The liquid diet provided energy, protein, minerals, trace elements, and vitamins in accordance with the requirements of ponies. As sole source of nutrition, the liquid diet fully counteracted fasting-induced hyperlipaemia in two healthy ponies. The liquid diet was also used in hyperlipaemic patients, but only in combination with conventional therapy, consisting of intravenous administration of glucose, insulin, and heparin. Although no patients were treated with the liquid diet alone, the liquid diet has potential in the treatment of hyperlipaemia - it is easy to prepare and to administer by nasogastric tube and it provides energy and nutrients to counteract the negative energy balance and low nutritional status of patients. Experience is needed with hyperlipaemic patients that are treated with the liquid diet only.

Effect of dietary medium chain triacylglycerols on plasma triacylglycerol levels in horses.

The hypothesis tested was that the feeding of medium chain triacylglycerols (MCT) to horses would raise the level of plasma triacylglycerols by increasing the availability of glucose as lipogenic substrate, implying that the MCT effect would be greater with glucose in the diet instead of cellulose. A Latin square experiment was carried out with 4 horses and 4 dietary treatments. The experimental periods lasted 21 d. Blood samples were taken 16 h after feeding. The diets consisted of hay and experimental concentrates, differing in fat source (MCT or soybean oil) and carbohydrate source (corn starch plus glucose or cellulose). The dietary variables, MCT or soybean oil, provided on average 27% of total dietary net energy, while glucose plus constarch or cellulose provided 33%. The feeding of MCT versus soybean oil raised the level of plasma triacylglycerols significantly from 196.7 +/- 30.2 to 427.3 +/- 85.7 mmol/l and that of VLDL cholesterol from 0.028 +/- 0.01 to 0.069 +/- 0.01 mmol/ml. As based on analysis of variance, for the four experimental diets there was no significant effect of carbohydrate source and no fat-carbohydrate interaction. Thus, the hypothesis was rejected. When the diets contained soybean oil, cellulose versus starch plus glucose produced significantly greater increase plasma triacylglycerols. This carbohydrate effect was not seen when horses were fed the MCT diets. The experimental concentrates did not differently influence the concentrations of plasma glucose, total serum cholesterol, phospholipids, insulin, free fatty acids and the activity of post-heparin lipoprotein lipase. We suggest that the MCT-induced increase in plasma triacylglycerols is related to an increase in hepatic VLDL secretion, with the extra substrate for increased synthesis of triacylglycerols being the acetyl-CoA derived from the hepatic oxidation of medium chain fatty acids.

[Energy and protein supply for event horses during training: comparison between intake and requirements]. / De energie- en eiwitvoorziening van militarypaarden in training: vergelijking van opname en behoeftenormen.

In horses that exercise intensively (for example, event horses in training) the intake and energy requirements were compared on the basis of a diet record and estimates of energy required for exercise. Daily net energy intake over a 7 days period was on average 30% (n = 15) higher than the net energy requirement. Since the horses had a constant body weight, and thus were in energy balance, the energy intake was overestimated and/or the energy requirement was underestimated. The intake of digestible protein was 92% higher than the protein requirement. This study illustrates the problems concerning ration assessment and evaluation in practice.

[Enteral, nutritional support for critically ill patients]. / Enterale, nutritionele ondersteuning van kritieke patiënten.

Critically ill patients are characterized by acute changes in their metabolism, which are described by the term 'hypermetabolism'. In combination with anorexia, hypermetabolism leads to a negative energy and nitrogen balance. Consequently, wound healing can be inhibited, resistance is reduced, and (multiple) organ failure can occur. With the aid of nutritional support these consequences can be counteracted. During hypermetabolism protein breakdown is increased, and it is necessary to supply extra protein in the diet of critically ill patients. The amino acid glutamine is an important source of energy for enterocytes, and extra glutamine can improve the protective function of the intestinal mucosa. Branched amino acids serve as energy source during the acute phase. Arginine can reduce symptoms of encephalopathy by improving the conversion of ammonia to urea. Extra arginine in the diet also improves resistance. Because of the increased energy demand, diets for critically ill patients should be rich in fat. Moreover, extra n-3 fatty acids can improve immune function. A diet supplemented with extra zinc seems warranted because of its beneficial effect on wound healing and its inhibitory effect on protein breakdown. The enteral route is preferred because it protects the mucosal barrier of the gut, and it is less expensive and easier than the parenteral route. An enteral diet for critically ill patients is presented. Various factors that determine the choice of technique for enteral feeding are discussed.

[Nutrition of horses: digestion, energy and protein evaluation and nutritional standards]. / Voeding van paarden: vertering, energie- en eiwitwaardering en voedernormen.

The diet of horses should cover the energy and nutrient requirements of these animals. The desired composition of the ration depends on its digestion in the equine gastrointestinal tract. Nutritional problems or diseases caused by incorrect composition of the ration or by incorrect feeding should be prevented. The digestion of carbohydrates, fats, and proteins in the different parts of the gastrointestinal tract is described. In addition, the recently introduced net energy and digestible protein evaluation systems for feeds, and the energy and protein requirements of horses are presented.

[Nutrition of horses: ration calculation and assessment]. / Voeding van paarden: rantsoenberekening en -beoordeling.

In various situations it is desirable to evaluate the diet of horses. Such situations occur when nutrition is considered as the cause of disease or symptoms or and when a diet or diet change raises concern about whether the animal is receiving sufficient nutrients. Ration evaluation consists of translating feed ingredients into nutrients supplied and comparing this with nutrient requirements. The basics of ration evaluation are illustrated by means of four examples of horse diets.