Antonius F. B. van der Poel

The effects of dietary fibre type on satiety-related hormones and voluntary food intake in dogs.

Depending on type and inclusion level, dietary fibre may increase and maintain satiety and postpone the onset of hunger. This 7-week study evaluated the effect of fibre fermentability on physiological satiety-related metabolites and voluntary food intake (VFI) in dogs. Sixteen healthy adult dogs were fed a low-fermentable fibre (LFF) diet containing 8.5 % cellulose or a high-fermentable fibre (HFF) diet containing 8.5 % sugarbeet pulp and 2 % inulin. Large intestinal fibre degradation was evaluated by apparent faecal digestibility of nutrients and faecal SCFA and NH3 concentrations. Postprandial blood samples were obtained to determine postprandial plasma glucose, insulin, total peptide tyrosine-tyrosine (PYY), total glucagon-like peptide-1 (GLP-1) and total ghrelin concentrations. At the end of the study, the dogs were given a single meal of a dry dog food to determine VFI. Dogs fed the HFF diet had a significantly higher large intestinal fibre degradation and production of SCFA compared with the dogs fed the LFF diet. The HFF-fed dogs tended (P = 0.058) to show a lower VFI at the end of the study. No treatment effects were found for postprandial plasma glucose, PYY, GLP-1 and ghrelin responses. The concentrations of these metabolites could not be related to the observed difference in VFI. The inclusion of fermentable fibre in canine diets may contribute to the prevention or mitigation of obesity through its effects on satiety. The underlying mechanisms require further investigation.

Effects of process conditions during expander processing and pelleting on starch modification and pellet quality of tapioca

In this study the effect of processing conditions during the manufacture of pelleted animal feed is related to the degree of gelatinization of tapioca starch as measured by the amyloglucosidase method (SGDAGS) and Differential Scanning Calorimetry (DSC). The process conditions used were related to some physical quality characteristics of the pelleted feeds as well. Physical pellet quality was evaluated for hardness and durability, which incorporated tests that are also used in the feed industry. The processing line used in the experiment consisted of a conventional barrel type conditioner where steam pressure (100–180 kPa) and tap water addition were varied (0–52 g kg−1 of the feed debit). Subsequently, expander processing was carried out and the screw speed of the expander was varied (60–140 rpm) as well as the amount of dissipated (expander) motor power (1.3–5.7 kW). Response surface regression methodology was used to assess the directions and relative magnitude of changes in processing conditions on starch modification, physical pellet quality and some system variables. The results show that no combination of independent factor levels can be found that satisfies one common maximum or one common minimum value for all of the dependent variables tested. Hardness and durability values of the pellets were most affected by steam pressure and the amount of expander motor power used, whereas starch modification was most affected by steam pressure and water addition. © 1999 Society of Chemical Industry

Extruding vs Pelleting of a Feed Mixture Lowers Apparent Nitrogen Digestibility in Dogs

The influence of extruding vs pelleting of a feed mixture on nitrogen, dry matter, fat and ash digestibility was investigated in six mature dogs. Extrusion decreased nitrogen digestibility, increased ash absorption and had no effect on dry matter and fat digestibility. After feeding the extruded diet, the pH of faeces was lowered and the faecal water content increased, suggesting that this diet stimulated bacterial fermentation in the intestine.

Effects of pretreatment of wheat bran on the quality of protein-rich residue for animal feeding and on monosaccharide release for ethanol production

The effects of hydrothermal conditions for pretreating wheat bran on the quality of residual protein for animal feeding, and on monosaccharide release for ethanol production were studied according to a 4×2×2 design with the factors, temperature (120, 140, 160, and 180°C), acidity (pH 2.3 and 3.9), and retention time (5 and 10 min). Temperature affected the quality of residual protein for animal feeding. Pretreatment at 120 and 140°C did not affect O-methylisourea-reactive lysine in protein-rich wheat bran residue, although total lysine decreased with increasing temperature at pH 2.3. At temperatures higher than 140°C, reactive lysine decreased and melanoidins, furfural and 5-HMF increased. Lower acidity during pretreatment at 120 and 140°C increased the digestibility of the residual wheat protein in vitro by 36%. Pretreatment conditions did not substantially affect the release of monomeric xylose and arabinose by hemicellulases, which suggests that arabinoxylans in wheat bran are well accessible for enzymes.

Effects of Water, Steam and Shear Conditioning on the Protein Quality of Soy Grits

The effect of adding steam (at 0·6 and 1·2 bar) and water (1·9% and 64% of the flux of soy grits) in a conventional barrel type conditioner and its effects on protein dispersibility index (PDI), nitrogen solubility in 0·2% KOH and trypsin inhibitor activity (TIA) of commercial soy grits was studied. In addition, conditioned soy grits were subjected to expander treatment at two different screw speeds (2 and 3 rps) and PDI, NSI and TIA were measured. Analysis of variance was used to determine the effects of steam pressure, water addition and screw speed on the mentioned protein quality parameters. In addition, resultant temperature from steam addition was used in an analysis of covariance to determine the effects of temperature as a covariate, water addition and screw speed on protein quality parameters. A significant interaction for steam pressure and water addition was found on all parameters. The highest denaturation or inactivation of the protein was found at the combination incorporating high steam and high water addition. Screw speed during expander treatment did not significantly affect protein quality parameters. It was concluded both from this study and from literature that PDI is a better parameter to evaluate technological treatments when low amounts of motor power are dissipated (<110 kJ kg-1) and that NSI in 0·2% KOH is a better parameter to discriminate between technological treatments when moderate to high amounts of motor power are dissipated in soy grits. TIA decreased with increasing water or steam content. The effect of trypsine inhibitor inactivation in soy grits was highest at higher temperatures and was not affected by screw speed of the expander.

Poultry by-Products

The tremendous growth of the poultry industry is creating a large amount of offal and waste. If sufficient care is taken, this offal may contribute to animal feed as essential diet ingredients, thus replacing parts of other expensive feed ingredients. Poultry industries now exist in many countries and generate large amounts of residues. The centralization of poultry processing has intensified the problem of disposal of poultry waste, the volume of which may be large enough to develop techniques of processing this offal or present possibilities for future use. The processing of poultry by-products will have a role in solving the protein needs and improving the human environmental struggle in countries where rendering plants are developing and animal proteins are not abundant.

The Effect of Extrusion Conditions on the Fermentability of Wheat Straw and Corn Silage

Wheat (Triticum aestivum L) straw and corn (Zea mays L) silage were extruded under variable conditions of temperature and screw speed. The resulting extrudates were then tested for their fermentability according to cumulative production of gas, and compared with each other and with the untreated material. VFA analysis was carried out at the end of fermentation, to assess the pattern of fermentation. Analysis of the cumulative gas curves showed significant differences between substrates. Extrusion treatment also led to significant differences, though the effect of screw speed and temperature were not always consistent. However, most differences in cumulative gas production were negative, particularly for wheat straw, which suggests that, under the conditions used, extrusion actually reduced the fermentability of the fibres.

Fruit, vegetable and brewers’ waste

Fruit and vegetable wastes as well as brewers’ dried grains are produced after processing. The processing of these wastes, being sources of plant protein and energy, is dependent on economic needs. For instance, the recovery of a useful material from processing wastes seems to be an ideal solution. However, the treatment cost of the waste stream will be increased, but a credit will be introduced owing to the sale or use of the recovered waste product, with its nutritive value as a feedstuff for farm animals and especially poultry. In developing market economics, however, the need for plant protein and energy is great while the production is never adequate. Waste residue from the vegetable, fruit and brewers’ industry is rarely identified or found in the developing market but as large-scale processing industries develop around the world, residues suitable for use as a feedstuff are bound to occur more often.

Dried poultry waste

The increased size of poultry units causes a tremendous accumulation of large amounts of manure. For instance, a flock of 100 000 layers kept in cages will produce more than 12 t daily or 4380 t a year. Because disposal of poultry manure as a fertilizer is not very promising, increased interest has developed in alternative methods of waste disposal. Alternative uses of poultry wastes are fuel production, fertilizers, fuel briquets and feedstuff ingredients. Recycling poultry waste after proper sterilization and processing has been advocated for two reasons: its useful nutrients can be used in a case of feedstuff shortage and to reduce pollution.

Apparent ileal digestibility of Maillard reaction products in growing pigs

The absorption of Maillard reaction products (MRP) from dietary origin has been linked to the occurrence of chronic diseases. The aim of the present study was to determine the effects of toasting time of rapeseed meal (RSM) and the processing method of the diets (pelleting and extrusion) that included RSM on the apparent ileal digestibility (AID) of total lysine, fructosyl-lysine (FL), carboxymethyl-lysine (CML), carboxyethyl-lysine (CEL), lanthionine (LAN) and lysinoalanine (LAL) in growing pigs. The study consisted of a 2×3 factorial design with toasting time of RSM (60, 120 min) and diet processing method (mash, pelleted, extruded) as factors. Fifty growing pigs were individually fed one of the experimental diets for 4.5 consecutive days. Following euthanasia, samples of digesta were collected from the terminal 1.5 m of the small intestine. Increasing the toasting time of RSM increased the contents of FL, CML and CEL, whereas the additional effects of the diet processing methods were relatively small. Lysinoalanine and lanthionine were not detected in the diets; therefore, digestibility of these compounds could not be determined. The contents of FL, CML and CEL in the ileal chyme were positively correlated to their contents in the diets. The AID of the MRP from thermally-treated RSM were overall low and were not related to their contents in the diets. The AID of FL ranged between -8.5 and 19.1%, whilst AID of CML and CEL ranged from -0.2 to 18.3 and 3.6 to 30%, respectively. In conclusion, thermal treatments have clear effects on the contents of MRP in the diets. These compounds have relatively low digestibility in growing pigs.