Prebiotics affect nutrient digestibility but not faecal ammonia in dogs fed increased dietary protein levels

An increased protein content and less digestible protein sources in the diet can induce bad faecal odour. The present study investigated the effect of adding prebiotics to dog diets enriched with animal-derived protein sources on apparent digestibilities and faecal ammonia concentration. In three subsequent periods eight healthy beagle dogs were fed a commercial dog diet that was gradually supplemented by up to 50 % with meat and bone meal (MBM), greaves meal (GM) or poultry meal (PM) respectively. Afterwards, 3 % fructo-oligosaccharides or 3 % isomalto-oligosaccharides were substituted for 3 % of the total diet. Supplementation with animal-derived protein sources did not decrease the apparent N digestibility significantly but oligosaccharides did. On the other hand the bacterial N content (% DM) in the faeces was highest in the oligosaccharide groups followed by the protein-supplemented groups and lowest in the control groups. When the apparent N digestibility was corrected for bacterial N no significant differences were noted anymore except for the GM group where the corrected N digestibility was still lower after oligosaccharide supplementation. The amount of faecal ammonia was significantly increased by supplementing with protein or oligosaccharides in the MBM and GM groups but not in the PM group. When apparent N digestibility is interpreted, a correction for bacterial N should be taken into account, especially when prebiotics are added to the diet. Oligosaccharides did not reduce the faecal ammonia concentrations as expected.     

Effects of feeding polydextrose on faecal characteristics, microbiota and fermentative end products in healthy adult dogs

Polydextrose is a potential prebiotic, but has not been well tested in dogs. Thus, the objective of the present study was to determine the effects of polydextrose on faecal characteristics, microbial populations and fermentative end products in healthy adult dogs. A total of eight adult hound dogs (3.5 (sem 0.5) years; 20 (sem 0.5) kg) were randomly allotted to one of four test diets containing the following concentrations of polydextrose: (1) 0 % (control); (2) 0.5 %; (3) 1.0 %; or (4) 1.5 %. A Latin square design was used, with each treatment period lasting 14 d (days 0-10 adaptation; days 11-14 fresh and total faecal collection). All dogs were fed to maintain body weight. Data were evaluated for linear and quadratic effects using SAS software. Although apparent total tract DM digestibility was unaffected, total tract crude protein digestibility tended to decrease (P < 0.10) linearly with increasing dietary polydextrose concentrations. Fresh faecal DM percentage tended to decrease (P < 0.10) linearly, while faecal scores increased (P < 0.05; looser stools) with increasing dietary concentrations of polydextrose. Faecal acetate, propionate and total SCFA concentrations increased (P < 0.05) linearly with increased dietary polydextrose. Faecal pH decreased (P < 0.05) linearly with increasing polydextrose. Faecal indole tended to decrease (P < 0.10) linearly with increasing polydextrose, but other faecal protein catabolites were not changed. Faecal Clostridium perfringens linearly decreased (P < 0.05) with increasing dietary polydextrose concentrations, but Escherichia coli, Lactobacillus spp. and Bifidobacterium spp. were not affected. Based on the present results, polydextrose appears to act as a highly fermentable fibre, but requires further research to test its potential as a prebiotic in dogs.     

Fiber-degrading enzyme increases body weight and total serum cholesterol in broiler chickens fed a rye-based diet

Broiler chickens were fed diets based on either outer or inner endosperm from rye. These diets were fed with or without a fiber degrading enzyme to study the effects of the dietary fiber fraction on production results, body composition, serum lipid concentrations and apparent ileal digestibility of nutrients. Elimination of the dietary fiber effect by the enzyme generally improved the production results and caused an increase in total serum cholesterol concentrations. On average, at d 21 of the experiment chickens fed the enzyme supplemented outer endosperm diet had body weights and serum total cholesterol concentrations -23% and 37% higher, respectively, than those of birds fed the corresponding unsupplemented diet. The body fat content tended to be higher and the protein content was generally lower in chickens fed enzyme-supplemented diets. Chickens fed the unsupplemented outer endosperm diet had a low apparent ileal crude fat digestibility of only 23%, and birds fed the enzyme-supplemented diet had crude fat digestibility that was 113% higher but still lower than that of birds fed the inner endosperm diet. Birds fed enzyme-supplemented diets generally had higher apparent ileal digestibilities of organic matter, crude protein, starch, crude fat and dietary fiber components.     

Gastrointestinal implications in the rat of wheat bran, oat bran and pea fibre.

The gastrointestinal (GI) effects of three different dietary fibre (DF) sources: wheat bran (WB), oat bran (OB) and pea fibre (PF), were compared with a low-fibre diet in a 4-week trial with rats (initial bodyweight 210 g). The DF sources varied widely in chemical composition, solubility and water-holding properties, and particle size. The DF sources were mixed into diets to comprise the same amount of non-starch polysaccharides (NSP; 135 g/kg dry matter (DM)). Compared with the control diet, all fibre-containing diets reduced apparent digestibility of DM, energy, and protein significantly but to different extents. The ranking order of faecal DM bulking followed that of NSP recovery in the faeces: WB > OB > PF > control. The elongating effect of the diets on the GI tract was most pronounced in the rats fed on the OB diet. The mean transit time (MTT) of the OB diet was similar to that of the control diet (approximately 37 h), which was significantly slower than the MTT of the WB and PF diets (approximately 23 h). The study confirms that no simple cause and effect relationship exists between chemical composition, physical properties, and physiological effects of dietary fibre and their effects along the GI tract.     

Nutritional studies on East African herbivores. 1. Digestibilities of dry matter , crude fibre and crude protein in antelope, cattle and sheep.

1. A series of digestibility trials was done using four animals of each of the following species: Friesian cattle (Bos taurus), Boran zebu cattle (Bos indicus), Corriedale sheep, fat-tailed sheep, eland (Taurotragus oryx Pallas), Coke's hartebeest (Alcelaphus buselaphus cokei Günther), Thomson's gazelle (Gazella thomsonii Günther) and bush duiker (Sylvicapra grimmia L.). 2. Two batches of pelleted food were prepared from ground maize cobs, cassava, whs (A-E) were prepared containing 65 (A)-135 (E) g crude protein (nitrogen times 6-25)/kg dry matter. The crude-fibre contents of all the diets were similar (120-138 g/kg dry matter). 3. The animals were given the high-protein diet (E), then given diets with decreasing protein contents finishing with the low-protein (A). The antelope and half the sheep were given diets from the first batch of pelleted food, the other four sheep and all the cattle were given diets from the second batch of food. 4. In sheep, there were significant differences in digestibility between the two batches of food. 5. There were no significant differences in the over-all mean digestibilities of all diets when given to cattle (both species) and sheep. However, with diet E, dry-matter digestibility was higher in sheep than in cattle (P smaller than 0-05): the reverse was true with diet A (P smaller than 0-001). Crude-fibre and crude-protein digestibilities followed a similar pattern. The differences between Corriedale and fat-tailed sheep were not significant. The only significant difference between the two species of cattle was the higher digestibility of crude protein in Borans given diet E (P smaller than 0-05). 6. The over-all mean digestibility of the dry matter was higher (P smaller than 0-001) in hartebeest and duiker than in sheep; in Thomson's gazelle (P smaller than 0-01) and eland (P smaller than 0-001) it was lower than in sheep. The values for crude-fibre digestibilities varied in a similar way. 7. The mean apparent digestibility of crude protein was higher (P smaller than 0-001) in eland, hartebeest and duiker than in sheep and gazelle. 8. The results are discussed in relation to the feeding habits and digestive physiology of the various species.     

Effects of viscosity and fermentability of dietary fibre on nutrient digestibility and digesta characteristics in ileal-cannulated grower pigs

Relative contributions of two functional properties, viscosity and fermentability of dietary fibre, on apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), digesta passage rate, N retention and SCFA concentration have not been established. Thus, eight ileal-cannulated pigs randomised in a double 4 × 4 Latin square were fed four diets based on maize starch and casein supplemented with 5 % of actual fibre in a 2 × 2 factorial arrangement: low-fermentable, low-viscous cellulose (CEL); low-fermentable, high-viscous carboxymethylcellulose (CMC); high-fermentable, low-viscous oat β-glucan (LBG); high-fermentable, high-viscous oat β-glucan (HBG). Viscosity and fermentability interacted to affect (P < 0·001) digesta viscosity and AID and ATTD of nutrients. These properties tended to interact to affect (P < 0·10) digesta passage rate and butyrate. Pigs fed the CMC diet had the lowest (P < 0·05) digesta passage rate and the highest (P < 0·001) AID of energy, crude protein and DM, and ATTD of energy and DM. Post-ileal DM digestibility was highest (P < 0·001) for pigs fed the CEL and HBG diets. Post-ileal DM digestibility had a negative, curvilinear relationship with the AID of energy and crude protein (R2 0·85 and 0·72, respectively; P < 0·001). Digesta viscosity had a less strong relationship with the AID of energy and crude protein (R2 0·45 and 0·36, respectively; P < 0·001). In conclusion, high-viscous, low-fermentable dietary fibre increases the proportion of a diet that is digested in the small intestine by reducing digesta passage rate.     

Associative effects between two fibre sources on ileal and overall digestibilities of amino acids, energy and cell-wall components in growing pigs

1. The associative effects of two fibre sources on ileal and overall digestibility of amino acids, energy and cell-wall components were studied by comparing wheat bran and soya-bean hulls in semi-purified diets given to growing pigs. 2. Castrated male pigs were prepared with ileo-rectal anastomosis to measure ileal digestibility, and overall digestibility was measured in pigs without anastomosis. 3. The three diets contained 190 g total fibre/kg dry matter (DM), derived from each fibre source or from a mixture of both fibre sources, so that each source provided half the amount of total fibre, and 170 g crude protein (nitrogen x 6.25)/kg DM by additions of casein. 4. The effects of fibre sources on the ileal digestibility of amino acids were additive for most amino acids; the only significant interactions were found for threonine, methionine and aspartic acid. In contrast with ileal digestibility, systematic negative interactions between fibre sources on overall digestibility of amino acids were noted. 5. There was no interaction between fibre sources in their effects on the digestibility of energy or of cell-wall components, irrespective of the site of digestion. The digestibility values were higher with soya-bean hulls than with wheat bran, especially at the faecal level. 6. It is concluded that ileal digestibility of amino acids provides a better estimate of amino acid availability, as ileal measurements allow a better discrimination between diets than faecal measurements when distinct fibre sources are used alone or in combination at the same total fibre content. In contrast, for energy, the measurement of digestibility at both faecal and ileal levels permits the estimation of the partition of available nutrients between the small and large intestines.     

Daily food intake and digestibility in rats.

The present work with growing rats was undertaken to study the effect of daily food intake (DFI) on true protein digestibility (TD), and apparent digestibility of dry matter (DM), energy (DE), starch, soluble dietary fibre (SDF) and insoluble dietary fibre (IDF). The design involved two different dietary combinations, barley + rapeseed meal (diet 1) and oats + wheat bran (diet 2). A slight but significantly negative relationship was seen between DFI and TD on diet 1 while no such relationship was found on diet 2. Although significant, DFI influenced DM digestibility of both diets only slightly. A similar situation could also be seen for the effect of DFI on DE. The digestibility of starch was significantly affected by DFI on both diets even though the lowest values were as high as 0.994. SDF digestibility (fermentability) was not influenced by DFI when the rats were given diet 1, while there was a significant negative effect of DFI on digestibility of SDF when diet 2 was given. The digestibility (fermentability) of IDF was not affected by DFI on either of the two diets. The results confirm the existence of a weak negative relationship between DFI and digestibility of a range of nutrients although the effect seems to be only marginal and of no importance under practical feeding conditions.     

The effect of abrupt changes in the concentration and frequency of feeding milk-substitute diets on the voluntary food intake of calves

1. To examine the relations between short- and long-term regulation of food intake in calves given milk-substitute diets, abrupt changes were made in the dry matter (DM) concentration of the diet (Expt 1) and in the frequency of feeding (Expts 2 and 3). 2. When calves, fed once daily, had the DM concentration of their diet changed, they drank the same volume of milk on the 1st day they received the new diet as they had on the previous days; so the DM intakes changed in proportion to the change in milk DM concentration. Over the subsequent 6 d, milk intake progressively increased when milk DM concentration was reduced. When the DM concentration of milk was increased the volume of milk drunk was reduced to a minimum value 2-3 d after the change in diet and increased thereafter. The size of the changes was dependent on the initial and changed DM concentrations of the milk. 3. In calves receiving milk-substitute diets containing 80-260 g DM/kg, milk intakes were reduced by up to 30% on the 1st day that calves were fed once daily instead of twice daily. Over the subsequent 13 d of once-daily feeding, milk intakes increased, particularly for calves given diets of low DM concentration. 4. Feeding the calves once daily reduced the digestibility of DM in Expt 2 but not the digestibility of crude protein (nitrogen x 6.25) and fat; diets containing lower concentrations of DM were particularly affected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of low-carbohydrate,high-fat diets on apparent digestibility of minerals and trace elements in rats

ObjectiveKetogenic low-carbohydrate, high-fat (LCHF) diets reduce growth and bone mineral density in children with epilepsy and in rats. Part of this effect might be due to a reduced availability of calcium in high-fat diets. The aim of this study was to determine mineral digestibility by total collection method in LCHF diets compared with a chow diet and a standard high-fat diet (HFD, high in fat and carbohydrates).MethodsTwelve-wk-old male Wistar rats were pair-fed isoenergetic amounts of either six different LCHF diets based on tallow and casein (crude fat 75%–50%, crude protein 10%–35%), with chow or with a HFD diet. Mineral-to-energy ratio was matched in all diets. Circulating parathyroid hormone was measured by immunoassay.ResultsThe apparent digestibility of calcium was reduced in all HFDs (high-fat diets, LCHF diets and the HFD diet) by at least 30% compared with the chow diet (P < 0.001). Fecal calcium excretion correlated positively with fecal fat excretion, presumably because of formation of calcium soaps. Apparent digestibility of phosphorous was higher in all HFDs. This resulted in a decrease of the ratio of apparently digested calcium to apparently digested phosphorous in all HFDs below a ratio of 1:1. Plasma parathyroid hormone was not affected by any diet.ConclusionThe alteration of apparent calcium and phosphorus digestibility may affect the impact of HFDs on bone metabolism.     

Water content of faeces is higher in the afternoon than in the morning in morning-fed dogs fed diets containing texturised vegetable protein from soya

Faecal moisture content can determine whether faeces appear soft or firm, and faecal character can influence whether owners are satisfied with a dog food. In a previous study, dogs appeared to produce softer faeces after noon. The purpose of the present study was to determine whether time of defecation affected canine faecal water content. A total of eight hound dogs were fed one of four canned diets as a single meal each morning for 1 week per diet in a Latin square design. All four diets contained approximately 77 % moisture and, on a DM basis, 24 MJ/kg gross energy, 23 % crude protein, 32 % crude fat, 31 % N-free extract and 1 % crude fibre. The proportion of dietary protein from soya-derived texturised vegetable protein (TVP):beef was 0:100, 14:86, 29:71 and 57:43, respectively. Soya carbohydrate partially replaced maize starch as TVP increased. Faeces were collected by direct catch during the sixth morning and afternoon of each diet period. Mean faecal moisture content was greater in the afternoon than in the morning (79 v. 71 %; P = 0.01) and increased with dietary TVP (P ≤ 0.0001), and there was an interaction between time of day and percentage TVP (P = 0.003). Faecal moisture content differed from morning to afternoon only with TVP in the diet. Faecal wet weight was similar from morning to afternoon. This suggests that time of day and presence of TVP from soya should be taken into account when evaluating the effect of a diet on faecal form and moisture content in dogs fed once daily.     

Interaction of soyasaponins with plant ingredients in diets for Atlantic salmon, Salmo salar L

The effects of combining soyasaponins with plant ingredients on intestinal function and fish health were investigated in an 80 d study with Atlantic salmon (270 g) distributed thirty each into twenty-four tanks with seawater. Soyasaponins were supplemented (2 g/kg) to diets with maize gluten (MG), pea protein concentrate (PPC) and sunflower (SFM), rapeseed (RSM) or horsebean meals. A diet with soyabean meal (SBM) and another with wheat gluten and soyasaponins served as reference diets. Marked soyasaponin effects were observed when combined with PPC. This combination induced inflammation in the distal intestine (DI) similar to SBM, reduced feed intake, apparent digestibility of lipid, most amino acids and ash, decreased bile salt levels in intestinal chyme and decreased leucine aminopeptidase (LAP) activity but increased trypsin activity in the DI. No enteritis was observed in other diet groups, but small consistent negative soyasaponin effects were seen on lipid and fatty acid digestibility, faecal DM and LAP activity of the DI. Soyasaponin combination with RSM reduced digestibility of all nutrients including minerals. The mineral effect was also seen for SFM, whereas with MG and SFM a positive soyasaponin effect on feed intake was observed. Caution should be exercised to avoid ingredient combinations giving high saponin levels, a condition that appears to be a key factor in diet-induced enteritis together with certain plant ingredients.     

The ratio of insoluble to soluble fiber components in soybean hulls affects ileal and total-tract nutrient digestibilities and fecal characteristics of dogs.

An experiment was conducted to evaluate the effects of soybean hulls (SH) containing varying ratios of insoluble:soluble fiber (I:S) on nutrient digestibilities and fecal characteristics of dogs. Ileally cannulated dogs (n = 6) were fed seven diets in a 6 x 7 Youden square arrangement of treatments. The seven diets included five SH-containing diets with I:S of 1.9, 2.7, 3.2, 5.2 or 7.2 and two diets containing either beet pulp (BP) or no supplemental fiber (control). Ileal digestibilities of DM, OM, CP, total dietary fiber (TDF), fat and gross energy (GE) were lower (P < 0.05) for dogs fed diets containing supplemental fiber compared with dogs fed the control diet. Fiber inclusion had a modest negative effect (P < 0.05) on total-tract DM, OM, fat and GE digestibilities compared with the control diet. Ileal digestibilities of DM and OM by dogs fed the SH treatments responded quadratically (P < 0.05) to I:S, with digestibility coefficients decreasing as the I:S approached 3.2. Highest ileal digestibilities were observed for diets with an I:S of 1.9 and 7.2. Similarly, a quadratic response (P < 0.05) was observed for digestibility of total amino acids at the ileum. Fecal outputs were lower (P < 0.001) when dogs consumed the control diet vs. fiber-containing diets. Among the SH-containing diets, there was a linear increase in fecal output as I:S increased (P = 0.031). The I:S in the diet affects DM and OM digestibilities at the ileum and affects fecal output, indicating that optimization of this ratio is desirable.     

Digestibility of a nutritionally-balanced cassava (Manihot esculenta Crantz) diet and its effect on growth in young male dogs.

Experiments were carried out to study the digestibility of a cassava (gari) diet and its effect on growth in young male dogs. Three groups of dogs were fed on diets with rice (control), cassava (gari), and rice + cyanide respectively as the carbohydrate source. Each diet contained 130 g crude protein (nitrogen x 6.25)/kg, was supplemented with vitamins and minerals, and was fed for 14 weeks. Variables measured were body-weight gain, bone growth, plasma alkaline phosphatase (EC 3.1.3.1) activity, total serum 3,5,3'-triiodothyronine (T3) and some plasma free amino acids. The apparent digestibilities of dry matter, protein and fat were not significantly different in the three groups, but the digestibility of gari fibre was significantly lower than the digestibility of rice fibre when fed to dogs (P less than 0.05). Proximate analysis of the faeces showed that the group of dogs fed on the gari diet had faeces which had a significantly higher moisture content than the faeces of the other groups (P less than 0.05), and also a significantly higher fibre content (P less than 0.05). There was no significant difference in body-weight gain and bone growth between the control and gari-fed groups of dogs, but these variables were significantly lower in the dogs fed on the rice + cyanide diet (P less than 0.05). At the end of the 14-week experimental period total serum T3 and plasma alkaline phosphatase activity were not significantly different between the control group of dogs and the gari-fed group, but were significantly lower in the rice + cyanide group. Plasma free methionine, leucine, isoleucine and valine concentrations were higher in the rice + cyanide group of dogs than in the control group and the gari group, indicating that these amino acids were accumulating and not being utilized for protein synthesis and growth to the same extent in the rice + cyanide group of dogs as in the other groups. It was concluded that the digestibilities of cassava starch and rice starch were the same in the dog but that rice fibre was more digestible in the dog than cassava fibre. It was also concluded that growth proceeded normally when a balanced gari diet or a balanced rice diet containing 130 g crude protein/kg was fed to dogs, but growth was retarded when a balanced rice + cyanide diet containing 130 g crude protein/kg was fed to dogs because total serum T3 concentration became greatly depressed.     

Carbohydrates digestibility and faecal nitrogen excretion in rats fed raw or germinated faba bean (Vicia faba)- and chickpea (Cicer arietinum)-based diets

Raw or germinated faba bean (Vicia faba minor var. Alameda) and chickpea (Cicer arietinum kabuli var. Athenas) seed meals were incorporated in essential amino acid-supplemented and energy-equalized diets for growing (65 (SD 1) g) male Wistar rats as the only sources of dietary protein. A lactalbumin-based diet was used as the control. Faecal dry weight and N excretion of animals fed legume-containing diets were greater (P<0.01) and DM digestibility lower (P<0.01) than controls. Apparent faecal digestibilities of amino acids were found to be not different or lower (P<0.01) than controls in rats fed diets containing legume seeds, either germinated or not. Total diaminopimelic acid (DAPA) and purine bases excretion were significantly (P<0.01) higher than controls in rats fed both legume seed meals. Faecal bacterial N calculated according to DAPA or purine bases values was similar and significantly higher (P<0.01) than controls in rats fed legume seed meals. Bacterial N accounted for 50 to 80 % of total faecal N in rats fed legume diets. Apparent faecal N digestibility values (53-65 %) of rats fed legume-based diets were lower (P<0.01) than controls, but became substantially higher (85-92 %) when calculated taking into account bacterial N values. Faecal NSP digestibility values for legume diets were 40-57 g/100 g ingested. Germination decreased starch faecal excretion (P<0.05) and increased (P<0.05) faecal starch and NSP digestibilities of faba bean seeds.     

两种玉米主食膳的人体表观消化率

<正> 在玉米仍占居民口粮比重较大的地区,一些主食制售与科研单位,正在研究玉米主食的加工制做方式。这种制品的营养价值,不能不引起人们的注意。包括玉米在内的粮食的营养价值,取决于其营养成分组成、在人体内的消化率和某些营养素的利用率。但就作为主食的制做方式而言,对其中营养素组成和利用率影响不大,因而此类工作的许多文献报告,均以其主要营养素的人体表观消化率为评价标志。     

The effects of a supplement of dietary fibre on faecal excretion by human subjects.

1. Four human subjects on strictly controlled diets were given a fibre supplement, 25 g Ispaghula husk (Isogel)/d, for 3 weeks. 2. Replicate diets and faeces were collected during two 5 d balance periods. The first period served as control for the second which occurred after the supplement had been fed for 2 weeks. 3. Diets and faeces were analysed for total solids, gross energy, total nitrogen, fat, available and unavailable carbohydrates. 4. Three of the four subjects showed a considerable increase in faecal bulk; total faecal weight was more than doubled in two subjects. In two subjects the increase was brought about mainly by extra fibre in the faeces accompanied by a higher proportion of faecal water whereas in one subject it was also an increased excretion of nutrients. One subject showed very little change in faecal bulk. 5. High values for the apparent digestibility of fibre were found during the control period; from 0.70 to 0.80. There was more variation during the experimental period when apparent digestibility of total fibre ranged from 0.47 to 0.82. Values arrived at for the minimum apparent digestibility of the fibre supplement were generally high; one subject appeared to digest Isogel completely. Isogel was degraded preferentially to the food-derived fibre; in particular, cellulose in the faeces was increased during the experimental period. 6. Only one subject showed distinct decreases in the apparent digestibility of energy, N and fat in the diet. The results do not therefore agree with the generally held view that increased fibre in the diet decreases the apparent digestibility of the other nutrients.     

Novel methodology allows simultaneous measurement of true phosphorus digestibility and the gastrointestinal endogenous phosphorus outputs in studies with pigs

Methodology was developed for measuring the gastrointestinal endogenous phosphorus (P) outputs and true P digestibility values in studies with piglets. Four barrows, average initial body weight 6.8 kg, were fitted with a simple T-cannula at the distal ileum and fed four diets according to a 4 x 4 Latin square design. Four cornstarch-based diets containing four levels of P (1.1, 2.1, 3.2 and 4.3 g/kg diet) on a dry matter (DM) basis were formulated from soybean meal (SBM). Each experimental period comprised 8 d with a 4-d adaptation and 4-d collection of ileal digesta and feces. The apparent ileal and fecal P digestibility values in SBM were affected (P < 0.05) by P levels in the assay diets. The ileal and fecal P digestibility values increased from -24.8 to 37.1% and from 18.8 to 42.5%, respectively, as P contents increased from 1.1 to 4.3 g/kg DM diet. Linear relationships (P < 0.05), expressed as g/kg DM diet intake, between ileal and fecal outputs and dietary inputs of P, suggested that the endogenous P outputs can be determined by linear regression analysis. The endogenous P output was higher (P < 0.05) in ileal digesta than in feces (0.86 +/- 0.09 vs. 0.31 +/- 0.06 g/kg DM diet intake). There was no difference (P > 0.05) between the true ileal (50.7 +/- 7.1%) and fecal (48.5 +/- 5.4%) P digestibility values in SBM. These results suggest that differences in P contents between assay diets are primarily responsible for the large variability in apparent P digestibility values reported within the same ingredient. Apparent digestibility values underestimate the true digestive utilization of P by approximately 25%. True rather than apparent P digestibility values should be determined and used in diet formulation for pigs. In addition, this study shows that the gastrointestinal endogenous P output is important in whole-body P requirement and homeostasis.     

Hydrolysed Formulas in the Management of Cow’s Milk Allergy: New Insights,Pitfalls and Tips

An allergy to cow’s milk requires the avoidance of cow’s milk proteins and, in some infants, the use of a hypoallergenic formula. This review aims to summarize the current evidence concerning different types of hydrolysed formulas (HF), and recommendations for the treatment of IgE- and non-IgE-mediated cow’s milk allergy and functional gastrointestinal disorders in infancy, for which some dietary intervention and HF may be of benefit to both immune and motor mechanisms. Current guidelines recommend cow’s milk protein (i.e., whey or casein) extensively hydrolysed formula (eHF) as the first choice for cow’s milk allergy treatment, and amino acid formulas for more severe cases or those with reactions to eHF. Rice hydrolysed formulas (rHF) have also become available in recent years. Both eHF and rHF are well tolerated by the majority of children allergic to cow’s milk, with no concerns regarding body growth or adverse effects. Some hydrolysates may have a pro-active effect in modulating the immune system due to the presence of small peptides and additional components, like biotics. Despite encouraging results on tolerance acquisition, evidence is still not conclusive, thus hampering our ability to draw firm conclusions. In clinical practice, the choice of hypoallergenic formula should be based on the infant’s age, the severity, frequency and persistence of symptoms, immune phenotype, growth pattern, formula cost, and in vivo proof of tolerance and efficacy.     

Cholesterol-lowering effects and utilization of protein, lipid, fiber and energy in rats fed unprocessed and baked oat bran.

The effects of the addition of 15% or 30% non-heated oat bran or 30% baked oat bran to a purified diet on apparent digestibility of dry matter, protein, lipid and fiber were measured in balance experiments with male Wistar rats. The effects of oat bran on dietary metabolizable energy, fecal bulking capacity and transit time of the ingested food were also studied. Heat processing of oat bran occurred in conditions of moisture and temperature similar to those of bread baking. Compared with the unprocessed oat bran, the baked product had a higher content of insoluble fiber, mainly due to higher Klason lignin content and a shift from soluble to insoluble beta-glucans. Relative to the fiber-free control diet, feeding the oat bran diets increased wet and dry fecal weight and decreased the transit time of the food. Fecal bulking capacity increased proportionally with oat fiber intake. Metabolizable energy of the diets, as well as apparent digestibility of dry matter and protein decreased with oat bran supplementation; on the other hand, lipid digestibility was not significantly changed. Baking of oat brain resulted in no statistically significant effects on dietary metabolizable energy or apparent digestibility of dry matter, protein, lipid and fiber. The measured metabolizable energy of oat bran ranged between 12.7 and 13.2 MJ/kg. Total plasma cholesterol concentration diminished with oat brain intake; non-heated and baked oat bran had comparable effects on plasma cholesterol. An inverse linear relationship (r = -0.80, P less than 0.1) was found between plasma cholesterol concentration and fecal excretion of bile acids.