Apparent Digestibility Of Crude Fat Research Articles

Oscillating dietary crude protein concentrations increase N retention of calves by affecting urea-N recycling and nitrogen metabolism of rumen bacteria and epithelium.

The purpose of this study was to investigate the effects of oscillating crude protein (CP) concentration diet on the nitrogen utilization efficiency (NUE) of calves and determine its mechanism. Twelve Holstein calves were assigned randomly into static protein diet (SP, 149 g/kg CP) and oscillating protein diet (OP, 125 and 173 g/kg CP diets oscillated at 2-d intervals) groups. After 60 days of feeding, the weights of total stomach, rumen and omasum tended to increase in calves fed OP. The apparent crude fat digestibility, NUE and energy metabolism also increased. In terms of urea-N kinetics evaluated by urea-15N15N isotope labeling method, the urea-N production and that entry to gastrointestinal tended to increase, and urea-N reused for anabolism increased significantly in calves fed OP during the low protein phase. These data indicate that urea-N recycling contributed to improving NUE when dietary protein concentration was low. In addition, the differentially expressed genes in rumen epithelium and the rumen bacteria involved in protein and energy metabolism promoted the utilization of dietary protein in calves fed OP.

Dietary Supplementation of EGF Ameliorates the Negatively Effects of LPS on Early-Weaning Piglets: From Views of Growth Performance, Nutrient Digestibility, Microelement Absorption and Possible Mechanisms.

Simple SummaryThis study aims to investigate how epidermal growth factor (EGF) attenuates the effect of lipopolysaccharide (LPS) on the growth performance, nutrient digestibility, microelement absorption of early-weaned pigs. A total of 48 early weaned piglets were randomly distributed to four groups consisting of a 2 × 2 factorial design. The main factors were the level of LPS (HLPS = high LPS: 100 μg/kg body weight; ZLPS = low LPS: 0 μg/kg body weight) and EGF (HEGF = high EGF: 2 mg/kg diet; ZEGF = low EGF: 0 mg/kg diet). Each group had four replicates and each replicate consisted of three piglets. The results showed that HLPS level decreased the growth performance and the apparent digestibility of crude fat, while HEGF level increased the average daily feed intake. The concentration of most microelements in the gastrointestinal tract chyme and feces were increased by HLPS level and decreased by HEGF level. The expression levels of most microelement transport-relative genes in the mucosa of gastrointestinal tissues were decreased by HLPS level and increased by HEGF level. In conclusion, dietary EGF could attenuate the negative effect of LPS exposure on the apparent digestibility of crude fat and microelement absorption through changing the expression levels of microelement transport-relative genes. EGF can be used as an additive to increase the essential trace elements absorption in the early weaning piglets.Epidermal growth factor (EGF) plays an important role in nutrients absorption. However, whether it can be an effective additive to improve the growth performance and nutrients absorption in lipopolysaccharide (LPS) challenged early weaning piglets is still unknown. A 14-days trial was conducted to investigate how EGF attenuates the effect of LPS on the growth performance, nutrient digestibility, microelement absorption of early-weaned pigs, and study the underlying mechanism. A total of 48 early weaned piglets, aged 25 days, were randomly distributed to four groups (control, EGF, LPS and EGF + LPS groups) consisting of a 2 × 2 factorial design. The main factors were the level of LPS (HLPS = high LPS: 100 μg/kg body weight; ZLPS = low LPS: 0 μg/kg body weight) and EGF (HEGF = high EGF: 2 mg/kg diet; ZEGF = low EGF: 0 mg/kg diet). Each group had four replicates and each replicate consisted of three piglets. The results showed that piglets injected with HLPS level significantly decreased the average daily gain (ADG), and significantly increased the feed conversion ratio (FCR) compared with the piglets injected with ZLPS level, while piglets fed HEGF level significantly increased the average daily feed intake (ADFI) compared with the piglets fed ZEGF level (p < 0.05). Piglets injected with HLPS level significantly decreased the apparent digestibility of crude fat compared with the piglets injected with ZLPS level (p < 0.05). Piglets injected with HLPS level significantly increased the concentration of most microelements in the gastrointestinal tract chyme and feces, and significantly decreased the expression levels of most microelement transport-relative genes in the mucosa of gastrointestinal tissues compared with the piglets injected with ZLPS level (p < 0.05). Piglets fed HEGF level significantly decreased the concentration of microelement in the gastrointestinal tract chyme and feces, and significantly increased the expression levels of the microelement transport-relative genes in the mucosa of gastrointestinal tissues compared with the piglets fed ZEGF level (p < 0.05). In conclusion, dietary EGF could attenuate the negative effect of LPS exposure on the apparent digestibility of crude fat and microelement absorption of early-weaning piglets. EGF and LPS influenced the absorption of essential trace element through changing the expression levels of microelement transport-relative genes in the mucosa of gastrointestinal tissues. In the early weaning piglets, EGF can be used as an additive to increase the essential trace elements absorption.

Effect of dietary grape pomace on fats digestibility in horses

Effect of dietary grape pomace on fats digestibility in horses

Effects of Brewer's spent grain and carrot pomace on digestibility, fecal microbiota, and fecal and urinary metabolites in dogs fed low- or high-protein diets1.

Brewer's spent grain (BSG) and carrot pomace (CAP) were used as fiber sources in low- or high-protein diets in dogs. Ten adult Beagles were involved in 5 feeding periods of 19 d in a cross-over design. Experimental diets contained 7.5% of total dietary fiber (TDF) from BSG or CAP and 20% or 40% of crude protein in dry matter. A diet with 3.5% TDF from both fiber sources and 20% crude protein was used as reference. Fecal dry matter was 27% higher for diets with BSG compared to CAP (P < 0.001). Apparent fecal digestibility of crude protein was 7% to 11% higher in diets with 40% protein concentration (P < 0.001), while apparent digestibility of crude fat was 2% to 3% higher for diets with CAP (P < 0.001). Carrot pomace increased the apparent fecal digestibility of TDF, phosphorus, and magnesium (P < 0.001), while 40% protein diets had a positive impact on TDF and sodium and a negative effect on magnesium apparent fecal digestibility (P < 0.001). Inclusion of CAP increased fecal short-chain fatty acids (P = 0.010), mainly acetate (P = 0.001). i-butyrate (P = 0.001), i-valerate (P = 0.002), biogenic amines (P < 0.001), and ammonium (P < 0.001) increased with higher dietary protein levels. Diet-induced changes in the fecal microbiome were moderate. Relative abundance of Bifidobacteriales was higher for the low-protein diets (P = 0.001). To conclude, BSG and CAP can be used as fiber sources in canine diets and are well tolerated even at higher inclusion rates, the effect on microbial protein fermentation seems to be limited compared to the dietary protein level.

Effect of pectin extracted from citrus pulp on digesta characteristics and nutrient digestibility in broilers chickens

The experiment was carried out to evaluate the effects of continuous ingestion of pectin on intestinal viscosity, intestinal transit time, excreta moisture content, nutrient digestibility and energy metabolism of broilers at starter and growth phases. We used 240 one-day-old Cobb male broiler chicks, distributed in a completely randomized experimental design. Treatments consisted of four concentrations of pectin (0, 10, 30 and 50 g kg-1) with six replicates of 10 birds each. The ingestion of pectin supplied in the feed by broilers at the starter phase increased intestinal viscosity and intestinal transit time, reduced excreta moisture, improved the use of apparent metabolizable energy, nitrogen-corrected apparent metabolizable energy, coefficient of apparent metabolizability, coefficient of nitrogen-corrected apparent metabolizability, apparent digestibility coefficient of crude protein and organic matter; worsened calcium utilization and coefficients of apparent digestibility of dry matter; and did not influence the coefficients of apparent digestibility of crude fat, ash and phosphorus. Pectin ingestion during the growth phase increased intestinal viscosity and apparent digestibility coefficients of ash and organic matter, but decreased the dry matter, crude fat, crude protein and calcium. Intestinal transit time, energy metabolism and apparent digestibility coefficient of crude protein showed quadratic behavior according to pectin levels in the feed. Therefore, pectin ingestion by broilers at the starter phase increases intestinal viscosity and intestinal transit time, reduces excreta moisture and improves energy utilization, whereas at the growth phase nutrient digestibility is decreased.

The nutritive value and phosphorus availability of yellow- and dark-seeded rapeseed cakes and the effects of phytase supplementation in broilers

Three experiments on 242 Ross 308 broiler females were conducted to evaluate the nutritive value of expeller cakes cold-pressed from 3 yellow-seeded lines (YRC 041, 036, and 022) and black-seeded winter rape (BRC), and the effects of phytase supplementation. The total P content and phytase activity were similar in YRC and BRC and averaged 9.5 g/kg and 411 U/kg, respectively. Total glucosinolate contents in YRC were from 8.7 to 10.2 μmol/g dry matter (DM), in BRC, 12.6 μmol/g DM, in which progoitrin constituted 6% to 15% in YRC, and 35% in BRC. In the first experiment, the apparent metabolizable energy (AME N ) and nutrient digestibility of cakes were determined on 5 groups of 10, three-week-old chickens. Apparent protein digestibility did not differ between YRC and BRC and averaged 79.8%. Apparent crude fat digestibility and AME N were higher in YRC in comparison with BRC due to the lower fat content in the latter, but AME N averaged 8.95 MJ/kg of fat-free DM and did not differ between YRC and BRC. In the second experiment, a digestibility trial was conducted on 12 groups of 8 three-week-old chickens fed semisynthetic diets containing 45% cakes unsupplemented or supplemented with phytase (500 or 1000 U/kg). Phosphorus retention from YRC and BRC did not differ and averaged 39%. It increased due to phytase supplementation to 45.5% and 51.7%, on average. The third experiment was conducted on 8 groups of 12 chickens between 8-35 days of age fed low-phosphorus diets containing 30% cakes, unsupplemented or supplemented with 1000 U phytase/kg. Birds fed diets with BRC had a lower feed conversion ratio and higher thyroid weight in comparison with YRC-fed birds. Phytase supplementation increased feed intake (P<0.01), body weight gain (P<0.01) and tibia

Persistency of methane mitigation by dietary nitrate supplementation in dairy cows

Feeding nitrate to dairy cows may lower ruminal methane production by competing for reducing equivalents with methanogenesis. Twenty lactating Holstein-Friesian dairy cows (33.2±6.0kg of milk/d; 104±58 d in milk at the start of the experiment) were fed a total mixed ration (corn silage-based; forage to concentrate ratio 66:34), containing either a dietary urea or a dietary nitrate source [21g of nitrate/kg of dry matter (DM)] during 4 successive 24-d periods, to assess the methane-mitigating potential of dietary nitrate and its persistency. The study was conducted as paired comparisons in a randomized design with repeated measurements. Cows were blocked by parity, lactation stage, and milk production at the start of the experiment. A 4-wk adaptation period allowed the rumen microbes to adapt to dietary urea and nitrate. Diets were isoenergetic and isonitrogenous. Methane production, energy balance, and diet digestibility were measured in open-circuit indirect calorimetry chambers. Cows were limit-fed during measurements. Nitrate persistently decreased methane production by 16%, whether expressed in grams per day, grams per kilogram of dry matter intake (DMI), or as percentage of gross energy intake, which was sustained for the full experimental period (mean 368 vs. 310±12.5g/d; 19.4 vs. 16.2±0.47g/kg of DMI; 5.9 vs.4.9±0.15% of gross energy intake for urea vs. nitrate, respectively). This decrease was smaller than the stoichiometrical methane mitigation potential of nitrate (full potential=28% methane reduction). The decreased energy loss from methane resulted in an improved conversion of dietary energy intake into metabolizable energy (57.3 vs. 58.6±0.70%, urea vs. nitrate, respectively). Despite this, milk energy output or energy retention was not affected by dietary nitrate. Nitrate did not affect milk yield or apparent digestibility of crude fat, neutral detergent fiber, and starch. Milk protein content (3.21 vs. 3.05±0.058%, urea vs. nitrate respectively) but not protein yield was lower for dietary nitrate. Hydrogen production between morning and afternoon milking was measured during the last experimental period. Cows fed nitrate emitted more hydrogen. Cows fed nitrate displayed higher blood methemoglobin levels (0.5 vs. 4.0±1.07% of hemoglobin, urea vs. nitrate respectively) and lower hemoglobin levels (7.1 vs. 6.3±0.11 mmol/L, urea vs. nitrate respectively). Dietary nitrate persistently decreased methane production from lactating dairy cows fed restricted amounts of feed, but the reduction in energy losses did not improve milk production or energy balance.

Wheat‐ and barley‐based diets with or without additives influence broiler chicken performance, nutrient digestibility and intestinal microflora

To our knowledge, there is scant literature on comparative broiler response to cereal diets high in soluble non-starch polysaccharides without or with enzyme, prebiotic, probiotic or synbiotic supplementation. In the present study, the effects of a wheat- and barley-based diet with or without supplemental xylanase plus β-glucanase, inulin, Enterococcus faecium or inulin plus Enterococcus faecium, on bird performance, digesta viscosity, nutrient digestibility and intestinal microflora were compared to a maize-based diet. In comparison to a maize-based diet, the wheat- and barley-based diet reduced (P < 0.05) body weight gain and feed intake, but did not affect to the feed-to-gain ratio. Apparent digestibility of crude fat and various fatty acids were decreased (P < 0.05) as well as apparent metabolisable energy corrected to zero nitrogen retention content. There was an increase (P < 0.05) in the viscosity of jejunal digesta and in the caecal numbers of Escherichia coli and lactobacilli, and a decrease in the ileal numbers of E. coli and lactobacilli. Performance parameters and nutrient digestibility were not affected (P > 0.05) by dietary inclusion of the additives used, with the exception that exogenous enzyme improved (P < 0.05) the apparent digestibility of crude fat and decreased the viscosity of jejunal digesta. Enzyme and Enterococcus faecium supplementation increased intestinal lactic acid bacteria, whereas inulin addition reduced the number of E. coli (P < 0.05). Addition of inulin-Enterococcus faecium decreased E. coli and increased bifidobacteria numbers in the caeca. Enzyme supplementation to a wheat- and barley-based diet significantly improved the apparent digestibility of dietary fat. All four additives had a beneficial effect on the intestinal microflora of broilers.

Effect of partial replacement of oats with sugar beet pulp and maize oil on nutrient utilisation in horses.

The objective of the present work was to assess the influence of partial replacement of oats with dried unmolassed sugar beet pulp (SBP) and/or maize oil on nutrient utilisation in horses fed a traditional hay and concentrate diet. The total tract digestibility of nutrients, urinary excretion and plasma parameters were studied in a 4 x 4 Latin-square design experiment with purebred Arabian geldings. Horses fed the SBP diets responded with a reduced (P<0.05) apparent digestibility of crude protein and feeding of maize oil resulted in an increased (P<0.05) apparent digestibility of crude fat. The apparent energy digestibility was unaffected by the replacement of oats with SBP, but increased (P<0.05) when maize oil replaced part of the oats. The urinary excretion of nitrogen increased (P<0.05) when maize oil replaced oats and the excretion of energy was higher (P<0.05) on the diets where oats were replaced by maize oil and SBP. There was a significant (P<0.05) effect across treatments of postprandial blood sampling time on plasma glucose and insulin concentrations. Also, plasma concentrations of glucose and insulin tended to be higher on the oats than on the SBP diets. In conclusion, the limited effects on the digestibility of nutrients and energy suggest that it should be possible to partially replace oats with maize oil and/or SBP in diets for horses without any impairing effects on the overall nutrient utilisation. However, the dietary-induced changes in the urinary excretion of energy and on plasma glucose and insulin levels, indicate a possible influence of dietary carbohydrate composition on nutrient utilisation at the organ level, which requires further study.

Fat digestion and faecal bile acid excretion in veal calves fed milk replacers containing either coconut fat or tallow

Thirty eight veal calves aged 7 weeks were fed milk replacers containing either coconut fat or tallow for a period of 15 weeks. Body weight gain was 114.2 ± 10.3 and 115.7 ± 22.5 kg (mean ± SD, n = 19, P > 0.05) for the calves fed the diets with either coconut fat or tallow, respectively. Faeces were collected during the last week of the trial. Apparent digestibility of crude fat was 93.3 ± 4.9 and 91.4 ± 3.4% ( P = 0.17) for the calves fed on either coconut fat or tallow, respectively. Group mean of bile acid excretion was higher in the calves fed coconut fat instead of tallow, but the difference was not statistically significant. For individual calves a significant ( P = 0.001), negative correlation coefficient ( r = −0.54) was computed for the relation between faecal bile acid excretion and apparent fat digestibility.

Effects of lecithin on fat utilization by weanling pigs

Abstract One digestibility experiment (Exp. 1) and one growth experiment (Exp. 2) evaluated 2% soy-lecithin as an emulsifier of 6% rendered fat in a two-phase starter diet program (phase 1 = d 0 to d 14 postweaning; phase 2 = d 14 to d 35 postweaning). In Exp. 1, there was no interaction between lecithin and rendered fat. Lecithin improved gain/feed (G/F) (P 0.1) on average daily feed intake (ADFI) or gain/ME. Rendered fat significantly improved ADG, ADFI, and G/F during phase 2 and overall, but had no effect on gain/ME (P > 0.1). In Exp. 2, lecithin did not improve digestibility of rendered fat, but rendered fat increased apparent digestibility of crude fat (P 0.1) on the utilization of GE or N by the pigs. Lecithin did not improve the utilization of rendered fat by weanling pigs in this study.

Effect of lecithin on the apparent ileal and overall digestibility of crude fat and fatty acids in pigs.

Four barrows of approximately 40 kg initial body weight, fitted with post-valvular T-cecum cannulas, were used to study the effect of lecithin as an external emulsifier on apparent ileal and overall digestibility of crude fat, fatty acids, and other dietary nutrients (DM, N, GE, crude fiber [CF], P, Ca, and Mg), as well as the utilization of N, GE, Ca, P, and Mg. Two levels of lecithin (0 and .24%) and two levels of rendered fat (0 and 6%) in cereal-soybean meal-based diets were investigated according to a 4 x 4 Latin square design. No significant interactions were found between lecithin and rendered fat for apparent digestibility of crude fat as estimated at the end of the small intestine and the total digestive tract. Lecithin decreased the apparent ileal digestibility of C16:0 fatty acid (P < .1) and the apparent overall digestibility of C14:0 fatty acid (P < .05) and C18:2 fatty acid (P < .1). The apparent ileal and overall digestibility of crude fat (P < .001) and total fatty acids (P < .05) increased with the inclusion of rendered fat in diets. Furthermore, rendered fat increased the apparent ileal and overall digestibility of C14:0 (P < .01), C16:1 (ileal, P < .001; overall, P < .1), and C18:1 (P < .05) fatty acids and the apparent overall digestibility of C18:0 (P < .001) fatty acid. Lecithin had no impact on the apparent digestibility and retention (percentage of intake) of GE, N, total P, Ca, and Mg.(ABSTRACT TRUNCATED AT 250 WORDS)

The Effect of Ash Content on the Nutritive Value of Meat and Bone Meal for Growing Pigs

Abstract A balance experiment was conducted with 9 barrows at live weight from 25 to 75 kg. The experiment had a 9 × 6 cyclic change-over design and the treatments were arranged factorially. The factors were three protein sources: soya bean meal (SBM), low ash meat and bone meal [MBL, 208 g ash/kg dry matter (DM)], and high ash meat and bone meal (MBH, 330 g ash/kg DM); and three protein supplementation levels: 20, 45 and 70 g crude protein/kg DM. The apparent digestibility of crude protein was SBM 0.897, MBL 0.755 and MBH 0.748. The nitrogen (N) retention increased linearly (p<0.001) as N intake increased, but the rate of increase was steeper for SBM diets compared with MBL and MBH diets. The pigs given MBH diets retained more N than those given MBL diets (p < 0.05), but no differences were observed in the rate of increase. The apparent digestibility of crude fat was SBM 0.729, MBL 0.690 and MBH 0.279. The determined digestible energy contents were SBM 16.62, MBL 13.38 and MBH 9.47 MJ/kg DM. The calcium,...

The effect of a straw meal on the crude protein and amino acid metabolism and digestibility of the crude nutrients in broiler hen breeds. 2. Digestibility of crude nutrients of rations and 15N from a straw meal and wheat

In experiments with colostomized broiler hens apparent digestibility of the crude nutrients of the ration after straw meal supplements of 20, 30 and 40 g per animal was determined. In addition, the 15N digestibility of straw meal and wheat was ascertained on the basis of straw meal supplements. The digestibility of the crude nutrients of the rations decreased significantly (P less than 0.05) after the straw meal supplement. The adaptation of the test animals to the straw meal intake resulted, at a daily consumption of 20 g straw meal, in an increase of the apparent crude fat digestibility (P less than 0.05) in dependence on the time of straw meal feeding, in which the original values without straw meal supplement were not reached. The digestibility of the 15N excess (15N') of the wheat was, at 86 +/- 1%, largely independent of the straw meal intake. The apparent digestibility of the straw-15N excess in broiler hens of 42 +/- 8 to 55 +/- 2% is surprisingly high.

Nutrition physiology effects of dietary fats in rations for growing pigs. 5. Effects of soy bean oil and lard on protein retention in piglets

In two experiments with 30 and 26 castrated male pigs of the German Landrace breed, weight range 15-30 kg, the influence of isoenergetic changes in the carbohydrate and fat fractions of the diet were examined. The effect of the addition of soya oil (SO) and lard (LA) to the diet on the utilization of protein and on the blood urea concentration was also examined. The apparent digestibilities of the crude nutrients and energy were determined using different methods. The following were examined: experiment I: ration I (control), ration II (+7% SO), ration III (+7% LA) experiment II: ration I (control), ration II (+2% SO), ration III (+2% SO + 5% LA), ration IV (+7% LA) In all experiments the animals were fed a similar amount of digestible crude protein of constant quality at constant ME-intake. In both experiments the apparent digestibility of crude protein in the groups with 7% added fat was 4% higher (p less than 0,05) than in the corresponding control groups. The apparent digestibility of crude fat in experiment I and II (in groups II and III and in groups III and IV, respectively) was approximately 87%, when calculated on the basis of faecal fat which was determined by a simple ether extract procedure. When the faeces was treated with HCl before determination, these values for experiment I and II were approximately 6% (p less than 0,001) and 1% (NS) lower, respectively. In both experiments the utilization of protein and the blood urea concentration were not significantly influenced by the amount or form of fat included in the rations.

Untersuchungen über ernährungsphysiologische Wirkungen von Futterfetten in Rationen für wachsende Schweine

Rations containing 12% sunflower oil (Ration II) and 12% coconut fat (Ration III) were compared with a control ration (Ration I) in a 34 day experiment with growing boars of the German Landrace breed (12-30 kg body weight). The relationships between DP and ME were held constant for all 3 rations, and because of the higher ME contents of the two fat rations, this was achieved by reducing the feed intake, relative to that of the control ration. Parameters measured were growth, composition at slaughter, the apparent digestibility of the crude nutrients and energy, the N-balance and the concentrations of urea, insulin, glucose, triglyceride and cholesterol in the blood. In comparison to Ration I, the apparent digestibilities of crude protein in Rations II and III were 5 and 4% (p less than 0,05) higher, respectively. There was little difference in the apparent digestibility of crude fat between the Rations II and III. However, large differences in the values were determined depending upon method of extraction. There were little differences in the productive performance of the animals fed the fat diets. The control animals had, however, a 13% lower growth rate (p less than 0,05) when compared at similar ME-intakes. As the energy concentration and the growth rate were higher in groups II and III, the feed conversion efficiency and the ME required per kg growth were approximately 30 and 13% lower than that of the control animals. The efficiency of protein utilization of the animals in group III was 4% higher (p greater than 0.05) and the blood urea concentration 20% lower (p less than 0.05) than that in group II. The values for the control animals were intermediate. A similar result was obtained concerning the fat content of the animals. The fat content of the animals in group III was 15.9% and this was significantly lower (p less than 0.001) than that of 21.1% measured in group II. That of the control animals, 18.6%, was not significantly different from the above values. The differences in feeding over the relatively short period of 34 days lead to marked differences in the fatty acid pattern of the backfat. The contents of myristic acid and linoleic acid were significantly different between group II and III; for the former values of 0.8% and 16.9% were determined, respectively, with corresponding values of 48.7 and 11.3% for the latter.(ABSTRACT TRUNCATED AT 400 WORDS)

Feed digestibility and mineral balance of the diet of young mice kept in mouse cages inside or outside an isolator, using varied concentrations of sodium phytate.

Young male mice of the C3H inbred strain were kept inside or outside a Trexler vinyl isolator and fed on three autoclaved purified diets which contained 0%, 1% or 5% sodium phytate. The feed N efficiency, the apparent digestibility of gross components of the diet, the balances of N, Ca, Mg and P, and the ash, Ca, Mg and P contents of bone were investigated for each group of mice. No significant differences in these parameters were found with respect to the location of the mouse cages inside or outside an isolator. Mice fed on 5% phytate diet, as compared with mice fed on 0% or 1% phytate diet, had a higher apparent digestibility of crude fat, and a lower apparent digestibility and retention rate of Mg. Urinary excretion and apparent digestibility of P in mice fed on 5% phytate diet were higher than in other groups of mice.

The influence of diet composition on the apparent digestibility of crude fat and fatty acids at the terminal ileum and overall in pigs

ZusammenfassungDer Einfluß der Futterzusammensetzung auf die scheinbare Verdaulichkeit von Rohfett und Fettsäuren beim SchweinIn 5 Versuchen mit 3 × 3 Schweinen, die mit Umleitungskanülen versehen waren, wurde der Einfluß der Futterzusammensetzung auf die scheinbare Verdaulichkeit von Rohfett und Fettsäuren untersucht.Aus den Ergebnissen geht hervor, daß der größte Teil des Fettes vor dem terminalen Ileum absorbiert wird. Die Fettmenge, die aus dem Dickdarm absorbiert wird, ist begrenzt, so daß mehr Fett über den Kot ausgeschieden werden kann als durch das terminale Ileum passiert. Die einzelnen Fettsäuren verhalten sich im großen und ganzen wie das Rohfett. Die scheinbare Verdaulichkeit von ungesättigten Fettsäuren ist höher als die der gesättigten Fettsäuren. Es ist zu beobachten, daß der Kot mehr Stearinsäure enthält als der Darminhalt, der in den Dickdarm gelangt. Das könnte auf eine Neusynthese von Fettsäuren hinweisen. Es scheint aber wahrscheinlicher, daß es zu einer Hydrogenierung von Fettsäuren kommt.Die scheinbare Verdaulichkeit von Rohfett und Fettsäuren steigt mit zunehmendem Gehalt an Fett in der Ration und fällt mit steigendem Rohfasergehalt der Ration.Relativ hohe Konzentrationen an flüchtigen Fettsäuren, insbesondere an Essigsäure werden im ilealen Darminhalt gemessen. Die Konzentration der flüchtigen Fettsäuren im Ileum und im Kot variieren proportional mit dem Rohfasergehalt in der Ration.Unterschiedlich hohe tägliche Trockensubstanzaufnahmen haben keinen Einfluß auf die scheinbare Verdaulichkeit von Rohfett und Fettsäuren.

Apparent digestibility of crude fat determined in trials with calves and pigs in relation to analytical methods applied.

Apparent digestibility of crude fat determined in trials with calves and pigs in relation to analytical methods applied.