Demonstration of uniformity of calcium absorption in adult dogs and cats

A meta‐analysis was conducted to understand quantitative aspects of calcium (Ca) and phosphorus (P) absorption in adult dogs and cats. 34 studies in dogs and 14 studies in cats met the criteria for inclusion in the meta‐analysis. Intake and faecal excretion values of Ca and P were subjected to a modified Lucas test and subsequent regression analyses. According to the current scientific consensus, Ca true digestibility (absorption) should increase at low Ca intake and decrease at high Ca intake. If true, this should result in a nonlinear relationship between the percentage of Ca excreted and dietary Ca intake. The present meta‐analysis showed a highly significant linear relationship (p < 0.0001) between Ca intake and Ca excretion suggesting a lack of systematic quantitative adaptation in true Ca digestibility. This finding suggests either that the time period covered by standard digestion trials is too short to induce adaptation mechanisms or that dogs and cats at maintenance will not efficiently alter quantitative Ca absorption percentage according to the amount ingested. If the latter is true, a dietary Ca supply differing greatly from the recommended dietary intake might impair the health of cats and dogs when fed long term. The data plots for P intake and faecal excretion were less uniform suggesting other factors not just dietary intake influence faecal P excretion. In adult cats, the dietary Ca:P ratio strongly influenced the true digestibility of P, whereas this effect was less marked in adult dogs. Faecal P excretion was significantly correlated to faecal Ca excretion in both species (p < 0.0001), and surprisingly, the level of P intake did not appear to be an important determinant of true digestibility of P.     

Digestive physiology of captive giant anteaters (Myrmecophaga tridactyla): determinants of faecal dry matter content

Giant anteaters (Myrmecophaga tridactyla) are specialized insectivores and consume mainly ants and termites in the wild. In captivity, giant anteaters are either fed a complete diet, or a combination of a domestic carnivore diet with leaf eater pellets, or a traditional gruel‐type diet. Soft faeces are a frequently encountered problem with this type of feeding. In the present study, we analysed diet and faeces composition, calculated digestibility and measured mean retention time on various diets in eight giant anteaters (total of n = 64 experiments). The results suggest that the digestive physiology of giant anteaters is similar to that of domestic dogs and cats in terms of nutrient digestibility and digesta retention. When testing correlations between faecal dry matter content and other variables, no relationship with dietary crude fibre content or mean digesta retention time could be detected. However, acid insoluble ash intake was significantly and positively correlated with faecal dry matter content. The amount of acid insoluble ash excreted with the faeces was higher than that ingested with the diet offered, indicating that the giant anteaters ingested soil from their enclosure of up to 93 g per day. This finding is consistent with observation of faeces of wild giant anteaters that contain soil or sand most likely due to indiscriminate feeding. It also corresponds to reports that indigestible materials such as peat, soil, chitin or cellulose contribute to a firmer faecal consistency in various carnivore species. Therefore, offering giant anteaters the opportunity to voluntarily ingest soil from their enclosure might be beneficial.     

Dietary lactulose decreases apparent nitrogen absorption and increases apparent calcium and magnesium absorption in healthy dogs

To study the effect of lactulose on the route of nitrogen excretion, we fed six healthy, adult dogs on diets containing either 0, 1 or 3 g lactulose/MJ metabolizable energy according to a 3 × 3 Latin square design. The results were analysed to identify statistically significant linear trend effects of lactulose. Faecal pH was significantly lowered by lactulose. Faecal ammonium and nitrogen excretion tended to be raised by lactulose feeding whereas urinary urea excretion was significantly reduced. Lactulose feeding significantly lowered apparent nitrogen digestibility. It is concluded that lactulose feeding shifts nitrogen excretion from urine to faeces in dogs which may be beneficial for liver patients. The data are in line with the concept that lactulose stimulates bacterial growth in the colon which in turn enhances faecal nitrogen excretion and lowers the entry of colonic ammonia into the bloodstream, leading to a lesser workload for the liver and less urinary nitrogen excretion. Lactulose consumption was also found to produce a dose-dependent increase in the apparent absorption of calcium and magnesium, but not phosphorus.     

Fibre analysis and fibre digestibility in pet foods--a comparison of total dietary fibre, neutral and acid detergent fibre and crude fibre

Six dry dog foods and six dry cat foods with different carbohydrate sources were investigated in digestion trials. Food and faecal samples were analysed for CF, TDF and starch. In dogs, also neutral detergent fibre (aNDFom) and acid detergent fibre (ADFom) were analysed. N-free extract (NfE) was calculated for CF, and similarly for all other fibre analyses. Linear regressions were calculated between fibre intake and faecal fibre excretion. True digestibility was calculated from the regression coefficients [true digestibility in % = (1 - regression coefficient)*100], with the intercept of the equation representing excretion of material of non-food origin. Crude fibre analyses gave the lowest values, and TDF the highest, while ADFom and aNDFom were in between. Variation between diets was lowest in CF and highest in TDF. Total dietary fibre, aNDFom and ADFom in food were positively correlated. Crude fibre in food did not correlate with any other method. The NfE analogue for TDF was closest to the starch content. Methods of fibre analyses in faeces did not agree very well with each other. Crude fibre had the lowest apparent digestibility, followed by ADFom, TDF and aNDFom. For all fibre analyses, there was a significant correlation between fibre intake and faecal fibre excretion. True digestibility was close to zero for CF, with a high uniformity in both species. In dogs, true digestibility of aNDFom was 53%, of ADFom 26% and of TDF 37%; in cats, true digestibility of TDF was 31%. Except for CF, the intercept of the regression equations suggest that faecal excretion of some material of non-food origin is analysed as fibre. A combination of TDF and CF analyses might give good information on the content of total (TDF), unfermentable (CF) and partially fermentable fibre (TDF-CF) in pet foods.     

Dietary effects on bifidobacteria and Clostridium perfringens in the canine intestinal tract

Dietary effects on the intestinal microflora have gained increasing interest because of the evidence that a balanced micro ecology in the gut is important for health and well being. The aim of the present study was to evaluate the effect of different diets on faecal counts of bifidobacteria and Clostridium perfringens in dogs. Two extruded, dry diets, one supplemented with 3% chicory (1.5% inulin), a non-digestible oligosaccharide (NDO) and the other with 3% glucose (GLU) were compared with a protein rich diet (PR+) based on low quality animal derived protein sources (NDO 265, GLU 259, PR+ 726 g crude protein/kg dry matter; greaves meal and bovine lung as protein sources in PR+). Nine adult beagles were subjected to a consecutive cross-over trial. All dogs started with diet PR+, after which groups of four dogs (group A) received GLU and the other five dogs (group B) received NDO. After an intermediate wash-out period with diet PR+ for 3 weeks the A dogs were switched to diet NDO and B dogs to GLU. In the final period all dogs were fed with diet PR+. Faecal samples were collected during each period for dry matter and pH measurements. Faecal bifidobacteria and Cl. perfringens were quantified in fresh samples at the end of each feeding period and additionally on the first days after feed change from the dry diets to diet PR+. Diets NDO and GLU increased faecal dry matter and reduced faecal pH from 6.9 to 7.4 with the high protein diet to 5.9-6.5. The dry diets induced a firmer faecal consistency and a lower faecal pH, with no significant difference between NDO or GLU. Clostridium perfringens was found in all faecal specimens after feeding PR+ with counts of log 8.2-8.8 colony forming units (cfu)/g faeces. Both dry diets reduced the counts of Cl. perfringens significantly (log 3.3-4.0 cfu/g faeces). Switching from the dry diets to the high protein diet induced an increase of Cl. perfringens within 1 day, independent of the previous diet. In dogs fed PR+, bifidobacteria were detected in only four faecal samples and exclusively in the initial feeding period. During the remainder of the experiment the counts fell below the detection limit (log 6 cfu/g faeces). The faecal concentrations of bifidobacteria increased with both dry diets. Slightly higher concentrations (log 9.6-9.7 cfu/g faeces) were obtained from dogs fed the dry diet containing NDO compared with the diet containing glucose (log 9.3-9.4 cfu/g faeces). The increase was small which may be related to the level of total fermentable carbohydrates in both diets which alone increase remarkably the total counts of bifidobacteria. In conclusion, distinct dietary effects on the faecal counts of Cl. perfringens and bifidobacteria with a clear antagonistic pattern were observed. The main factor was the protein source and level in the diet. In this case, NDO favoured the concentrations of bifidobacteria to a limited degree. Further studies are needed to evaluate time effects, metabolic consequences and the potential implication for health promotion in pets.     

The effect of salt and bentonite supplementation on feed and water intake, faecal characteristics and urine output in sheep

The effects of the addition of salt (sodium chloride) and sodium bentonite to hay-based pelleted rations on feed and water intake, digestibility, the output of urine and faeces, and faecal consistency were evaluated under conditions resembling those used for the shipment of live sheep. The addition of salt to the diet had no effect on dry matter intake but increased water intake relative to controls (P<0.01), with commensurate increases in urinary output of more than 1 litre/sheep/day. The diet with bentonite plus salt resulted in a higher dry matter intake than controls (P<0.01). The addition of bentonite increased the faecal dry matter percentage (P<0.05). The effects of the additives on faecal water evaporative loss and hardness were not significant. A large variation (52.1-62.6%) between sheep in dry matter digestibility of feeds was not affected by treatment and this requires further investigation. It is recommended that salt not be added to diets used for live sheep shipments.     

Evaluation of a microwave method for dry matter determination in faecal samples from weaned pigs with or without clinical diarrhoea

Microwave drying as a procedure for determination of faecal dry matter in weaned pigs was evaluated and clinical relevant cut-off values between faecal consistency scores were determined. Repeatability and reproducibility were evaluated. Overall coefficient of variation was 0.03. The 95% confidence limits for any future faecal subsample examined by any operator in any replica were ± 0.85% faecal dry matter. Robustness in relation to weight of wet faeces was evaluated. The weight categories were 0.5, 1.0, 1.5, 2.0 and 3.0 g. Samples of 0.5 g gave significantly different mean faecal dry matter content compared to weighing of 1.0-3.0 g. Agreement with freeze-drying was evaluated. Lin's concordance correlation coefficient was 0.94. On average the faecal dry matter values was 1.7% (SD=1.99%) higher in freeze dried compared to micro waved samples. Non-parametric ROC analyses were used to determine optimal faecal dry matter cut-off values for clinical faecal consistency scores. The 4 consistency scores were score 1=firm and shaped, score 2=soft and shaped, score 3=loose and score 4=watery. The cut-off values were score 1: faecal dry matter content >19.5%, score 2: faecal dry matter content ≤ 19.5% and >18.0%, score 3: faecal dry matter content ≤ 18.0% and >11.3%, score 4: faecal dry matter content ≤ 11.3%. In conclusion, the microwave procedure has an acceptable repeatability/reproducibility and good agreement with freeze drying can be expected. A minimum of 1.0 g of wet faeces must be used for analyses. Faecal dry matter cut-off values between 4 different clinical consistency scores were determined.     

藏猪对饲粮纤维的消化及其与肠道微生物的相关性研究

旨在研究藏猪对饲粮纤维素和半纤维素的消化及其与粪便细菌的相关性,探索藏猪具备较强纤维降解能力的潜在因素。采用消化试验测定150 d放牧藏猪、舍饲藏猪和商品猪（杜×长×大猪,DLY猪）对饲粮纤维的表观消化率。采集粪便样品利用单分子实时测序技术,测定粪便细菌16S rRNA基因全长序列,分析粪便细菌群落的结构和多样性,采用Spearman相关分析获取饲粮纤维表观消化率与粪便中细菌群落的相关性。结果表明,放牧藏猪对饲粮纤维素和半纤维素的表观消化率显著高于舍饲藏猪与DLY猪（P<0.05）。在放牧藏猪、舍饲藏猪与DLY猪粪便细菌中共鉴定出15个门、26个纲、48个目、87个科、190个属、419个种。放牧藏猪粪便细菌中有1个门纤维杆菌门（Fibrobacteres）、3个属拟普雷沃菌属（Alloprevotella）、纤维杆菌属（Fibrobacter）与琥珀酸弧菌属（Succinivibrio）、3个种（Alloprevotella rava、Fibrobacter intestinalis、Succinivibrio dextrinosolvens）相对丰度显著高于舍饲藏猪与DLY猪（P<0.05）,并与饲粮纤维表观消化率呈显著正相关（P<0.05）。综上所述,放牧藏猪具备较强的纤维消化能力,这种能力与粪便中的纤维降解菌密切相关。     

Cellulose fermentation capacity of the hindgut and nitrogen turnover in the hindgut of sows as evaluated by oral and intracecal supply of purified cellulose

Adult sows fed a constant amount of a basal diet received purified cellulose either orally at levels of 0 and 475 g/animal.d (Experiment 1) or intracecally at levels of 0, 285, 570 and 855 g/animal.d (Experiment 2). Each experiment consisted of subsequent periods of faeces and urine collection with the animals re-allocated to the treatments each time. With that, a total of 36 observations on each parameter was achieved. The faecal samples were analyzed for the contents of organic matter, cell wall carbohydrates and various nitrogen fractions such as bacterial N and undigested dietary N. Furthermore, N balance, urinary allantoin excretion and plasma urea concentrations were determined. In a preliminary study, the effects of freeze-drying and of shaking of the faecal samples as suspensions with water (in order to release bacteria from fibre) on content and composition of faecal nitrogen had turned out to be reproducible. Cellulose significantly enhanced faecal nitrogen loss whereas N retention was not affected due to the counteraction of urinary N loss. Plasma urea concentration reflected the situation with urinary N. The proportion of undigested dietary N and of water-soluble protein in total faecal N was somewhat increased by cellulose at cost of the bacterial N proportion which accounted for about 72% of total N on average. Urinary allantoin did not respond to the higher bacterial activity in the hindgut in the presence of supplementary cellulose. Cellulose significantly decreased the apparent N digestibility by on average about 3 percentage units per 100 g of supplementary cellulose. True N digestibility was also reduced by cellulose but did not go below 95%. The supplementary cellulose was fermented in the hindgut at similar rates of on average about 60% regardless of the route of administration. The almost 100 g of native cellulose incorporated in the basal diets were lignified by about 20%, and that is why they were fermented at a rate of only about 30%. The rate of fermentation was only slightly decreasing with increasing amounts of supplementary cellulose, and a daily quantity of 564 g (11 g/W0.75) cellulose was fermented on average if the highest level of cellulose was provided. This was within a range exclusively reported for easily-fermentable carbohydrates but was achieved in the case of cellulose only at a consistently higher level of supply. The true efficiency of bacterial protein synthesis was 5.2 g bacterial protein/100 g supplementary cellulose on average. The apparent efficiency was 60% higher averaging 8.4 g bacterial protein/100 g further apparently fermented organic matter.     

Effect of type of starch and quantity in rations on apparent and true digestibility of nitrogen and nitrogen balance in sheep

In a digestibility trial 5 semisynthetic rations were fed in 3 periods to 10 male sheep to examine the effects on N balance, components of faecal nitrogen and N digestibility. The rations contained constant amounts of nitrogen but different contents of cellulose and two different types of starch (untreated and steamflaked). Content and type of starch did not show any noticeable effect neither on excretion of undigested dietary nitrogen nor on true digestibility. There could not be noticed any effects on the apparent N digestibility by changing contents of cellulose or untreated starch. If the rations contained steamflaked corn starch, the animals excreted more faecal nitrogen and therefore showed a lower apparent N digestibility. Especially the water soluble N fraction of the faecal nitrogen was clearly higher. Compensation took place through a lower N excretion with the urine. The reason for increased faecal N excretion may be higher microbial protein synthesis in the rumen. This was accented by the allantoin excretion with the urine.     

Adaptation to the digestion of nutrients of a starch diet or a non-starch polysaccharide diet in group-housed pregnant sows

A trial was conducted with twenty group-housed pregnant sows to study the adaptation in nutrient digestibility to a starch-rich diet or a diet with a high level of fermentable non-starch polysaccharides (NSP) during a time period of 6 weeks. The starch-rich diet was primarily composed of wheat, peas and tapioca, whereas soya bean hulls and sugar beet pulp, which both are highly fermentable NSP sources, were used to formulate the NSP-rich diet. The starch-rich diet and the NSP-rich diet were formulated to contain different levels of starch (298 vs. 78 g/kg) and fermentable NSP (100 vs. 300 g/kg), but a similar level of net energy (NE) (8.36 MJ/kg). The trial consisted of a 1-week adaptation period followed by a 5-week collection period. Weekly apparent faecal digestibilities of dry matter (DM), crude protein (CP), crude fat, ash and NSP were measured by using the acid-insoluble ash marker method. Apparent faecal digestibilities of DM and organic matter (OM) of both diets were similar. Faecal digestibility of CP and crude fat was lower (p < 0.001) whereas that of NSP was higher (p < 0.001) for sows that received the NSP-rich diet. Calculated NE values of both diets were similar. Sows fed the NSP-rich diet produced faeces that contained a lower (p < 0.001) DM content compared with sows that were fed with the starch-rich diet. The quantity of dry faeces was the same on both diets, therefore total faeces production (as-is basis) was higher (p < 0.01) for the sows fed the NSP-rich diet. During the 5-week collection period, no changes were observed in the digestibility of DM, OM and NSP in the NE value of the diets. Digestibilities of CP and fat, however, were lower in week 1 (p < 0.05) compared with weeks 2-5 for both diets. The DM content of the faeces and the quantity of dry faeces did not change from weeks 1-5. Diet by time interaction was not observed for any of the response variables indicating that sows adapt as quickly to a diet with a high level of fermentable NSP as to a starch-rich diet. The present trial shows that, with regard to digestibility of nutrients, pregnant sows completely adapt to a NSP-rich diet (i.e., NSP from sugar beet pulp) in 2 weeks and that the time period necessary to adapt to a starch-rich diet or a diet with a high level of fermentable NSP is similar.     

Effect of different fibre types on the digestibility of nutrients in cats

In this study the effect of different fibre types was investigated on the acceptance of foods (in a short-term study) and on the nutrients' digestibility by using 10 adult, castrated cats. Peanut hull (PH, source of lignin), dried sugar beet pulp (SBP, source of hemicelluloses and pectin) and alfalfa meal (ALF, source of cellulose) were mixed to a poultry meat based cat food in 10% on dry matter (DM) basis. The average DM intake did only slightly differ according to the type of fibre added. Supplementation of basal food by dried SBP did not influence the digestibility of DM and crude protein (CP) significantly. Using ALF as a fibre source decreased the digestibility of DM (85.8% vs. 78.6%) and CP (93.8% vs. 92.0%) significantly. More severe decline could be observed in the digestibility of DM (85.8% vs. 63.4%) and CP (93.8% vs. 83.7%) when using PH as a fibre source. Fibre sources also influenced the stool DM content significantly. While application of PH increased the DM content of the faeces (45.0% vs. 49.6%), the use of dried sugar beet or ALF reduced the faecal DM content (45.0% vs. 24.1% and 39.0%, respectively). According to these results the less digestible fibre source (PH) increased the DM content of the faeces while by improving the digestibility of the fibre sources the DM content of the faeces decreased. It can be concluded, that not only the absolute fibre content of the food but also the type of fibre must be taken into account when evaluating its possible role as a component of weight loss products.     

The effect of oligofructose on urea metabolism and faecal odour components in cats

The effect on urea metabolism by the supplementation of oligofructose to a reduced protein diet was evaluated in cats by the use of labelled urea. The effect on faecal odour was also evaluated. Four cats were tested in a crossover study with two treatments: control and fructo-oligosaccharide (FOS). The FOS was supplemented at 3.11% on dry matter (DM) basis to a reduced protein diet (28.9% DM). After an adaptation period of 3 weeks, faeces and urine were collected during a 5-day collection period. Fresh faecal samples were collected for determination of odour components. On the first day of the collection period, labelled urea was injected subcutaneously. Urine production was estimated by potassium excretion. The fresh faecal samples were incubated in an air-closed recipient with two solid-phase micro extraction (SPME) fibres to bind the produced sulphur (S)-containing components. The reduced protein diet decreased plasma urea concentration but FOS supplementation had no effect. The tendency for a higher faecal output by FOS supplementation was the consequence of both an increased moisture content and faecal DM production. Supplementation of FOS showed tendencies to increase total faecal nitrogen (N) excretion and faecal (15)N excretion and tended to decrease urinary (15)N excretion. Twenty-seven different odour components were detected but were not affected by FOS supplementation.     

The effects of Buscopan compositum on calf nutritional diarrhoea

Nutritional diarrhoea was induced in male Friesian calves by the addition of sucrose to their milk replacer diet in two experiments. In each study the calves were paired on the basis of the severity of the diarrhoea and each of a pair of calves was assigned at random to receive a course of six intramuscular injections (5 ml/50 kg body weight) of either a placebo or Buscopan compositum (morning and evening) over a period of 3 days. In an initial study, which involved 10 pairs of calves, daily faecal and urine output were collected separately for each calf on the day prior to the start of treatment and on each day of the 3 treatment days. The daily output of fresh faeces was reduced as a result of treatment with Buscopan compositum and the overall reduction for the complete 3 day period was 18.7%. This was also reflected in a reduced output of faecal water (18.4%) during the same period. The digestibility of the dry matter component of the diet was significantly increased by 5.8%.In a second experiment, which involved 24 pairs of calves, faecal samples were collected daily, commencing before initiation of treatment, for determination of faecal dry matter content. The pattern of change in the faecal dry matter content during the course of the study differed clearly for the two treatments. Faecal dry matter increased from its lowest level (11.7%), immediately prior to first treatment, to its maximum (21.8%) on the second day of treatment in the Buscopan compositum-treated calves. In the placebo-treated calves, however, the faecal dry matter content increased gradually until the end of the study, at which time it was still 9.8% lower than that of the Buscopan compositum-treated calves on the second day of treatment.The results of these studies show that Buscopan compositum has a useful role to play in the management of nutritionally induced calf scour.     

Yttrium oxide (Y2O3) as an inert marker in digestibility studies with dogs, blue foxes and mink fed diets containing different protein sources

The study evaluated the use of yttrium oxide (Y(2)O(3)) as an inert marker in studies of apparent total tract digestibility in dogs, blue foxes and mink. Comparison was made with total faecal collection, and use of chromic oxide (Cr(2)O(3)) as marker respectively. Four experimental diets were added 0.1 g/kg yttrium oxide and 10 g/kg chromic oxide and fed to four animals of each species. Faecal recovery of yttrium oxide was 94.4% (SEM +/- 1.0), and of chromic oxide 105.8% (SEM +/- 1.5). The digestibilities of dry matter, crude protein, crude fat, starch and total carbohydrates obtained by total collection and yttrium oxide as marker showed close similarity, and in most cases not significant differences, independent of species and diets. In dogs, overall digestibilities of main nutrients with chromic oxide as marker were not significantly different from overall means obtained with yttrium oxide (p > 0.05). Overall digestibility of dry matter, crude protein and total carbohydrates in blue foxes and mink was significantly higher with chromic oxide than with yttrium oxide (p < 0.05). In dogs and blue foxes, digestibilities of individual amino acids determined by use of yttrium oxide were not different from values obtained using total collection of faeces, both within diets and for overall mean (p > 0.05). Overall amino acid digestibilities in dogs determined with chromic oxide as marker were similar to corresponding figures for yttrium oxide, whereas use of chromic oxide resulted in significantly higher digestibilites for a number of amino acids compared with yttrium oxide in foxes and mink (p < 0.05). The digestibilities of most main nutrients and amino acids revealed no interaction between diet and method (p > 0.05). The study showed that yttrium oxide can be used in low concentration in the feed, and allows high accuracy of analyses and thereby precise digestibility determination. It is concluded that yttrium oxide is an alternative inert marker to chromic oxide in the studied species.     

Effect of thermal treatment of potato products on nutrient decomposition in the digestive tract of swine. 1. Passage and digestibility of nutrients in the various portions of the intestine

In addition to a basic ration (barley, dried green fodder, fishmeal) pigs (castrated males, 100 ... 130 kg live weight) received a supplement of raw potato starch, raw ensiled potatoes, cooked potato starch or steamed ensiled potatoes; nutrient and amino acid passage and digestibility (absorption) were measured in the small intestine, the upper large intestine and the total digestive tract with the help of simple cannulae at the distal ileum and the middle of the hind gut and the estimation of the HCl insoluble ash as an indicator. In addition, the amounts of bacteria in faeces were determined and the influence of raw and cooked potato starch on N retention was ascertained. When raw potato products were fed, distinctly higher amounts of dry matter, organic matter and starch pass the ileum, which get into the colon undigested, i.e. the digestibility of these substances is low at the end of the ileum (raw potato starch 24%, starch of raw ensiled potatoes 36%). Up to the middle of the colon there is intensive bacterial starch degradation so that in this place the difference between raw and thermically treated potatoes is only small. No matter what the previous treatment of the potatoes was, there is hardly any starch in faeces, i.e. it was nearly 100% digested up to the end of the digestive tract. The passage and digestibility resp. of ash and crude cellulose from the basic ration is not influenced by the supplement of raw or thermically treated potato products in the individual sections of the digestive tract. At the end of the ileum there are no differences between the apparent digestibility of the crude protein and absorption of amino acids of supplemented raw or cooked potato starch or steamed ensiled potatoes; after the use of raw ensiled potatoes they are, however, significantly more reduced than the comparison of analyses of faeces shows. In the large intestine the high amount of potato starch stimulates the metabolism and the reproduction of faecal bacteria as is shown by an increase by 20-30% in bacteria N excretion in faeces. Apparent crude protein digestibility and amino acid absorption are diminished by that. The increased N excretion in faeces after the supplement of raw potato starch to the basic ration is-in comparison with the supplement of heated starch-compensated by a commensurately lower N excretion in urine so that N retention practically remains uninfluenced by the supplement of variously treated potato starch.(ABSTRACT TRUNCATED AT 400 WORDS)     

Dietary carbohydrates affect caecal fermentation and modify nitrogen excretion patterns in rats. II. Studies with diets differing in protein quality.

In 2 two-factorial experiments, each conducted on 80 growing male rats, the effects of substituting 10% raw potato starch (PS), pectins (PEC), or cellulose (CEL) for wheat starch (WS) and the addition of tannic acid to WS (WSTA) were studied using diets differing in protein quality. Casein unsupplemented or supplemented with DL-methionine and gluten unsupplemented or supplemented with lysine, methionine and tryptophan were used as protein sources in Experiment 1 and 2, respectively. Parameters indicative of caecal fermentation intensity (pH, acetic, propionic and butyric acid contents, digesta and tissue weight) and of protein metabolism (urea blood concentration, faecal and urinary nitrogen excretion) were determined. Ten-day balance experiments were preceded by a 10-day adaption period to respective carbohydrates given in a diet containing balanced protein. In both experiments the type of carbohydrates affected the caecal concentration of individual and total SCFA and other parameters of fermentation intensity. Pectins and potato starch were fermented more intensively than cellulose. Faecal N excretion was increased by all carbohydrates substituted for cereal starch, and by tannic acid. Urinary excretion was greater on CEL than on PEC and WSTA containing casein and on other diets containing gluten. In both experiments urinary N excretion was the lowest on PEC diets. Protein quality had the greatest effect on apparent biological value and net protein utilization but all indices of protein utilization were also affected by carbohydrates. It is concluded that not only the amount of N excreted in faeces but also in urine is affected by the type and fermentability of carbohydrates.     

Influence of age and body size on the digestibility of a dry expanded diet in dogs

The objectives of the study were (i) to evaluate the effects of age and body size on the apparent digestibility of a dry expanded diet and (ii) to determine whether poor faecal quality could be related to lower nutrient utilization. Four breeds of dogs were used: six Miniature Poodles (MP), six Medium Schnauzers (MS), six Giant Schnauzers (GS) and six Great Danes (GD). Digestive trials were performed at 11, 21, 35 and 60 weeks of age. Faecal moisture and scoring were recorded at the same periods. Digestibility coefficients of all macronutrients increased significantly (p < 0.05) with age in all four breeds. Organic matter digestibility increased from 80.2 +/- 1.5 to 85.5 +/- 1.5% in MP; from 80.2 +/- 0.9 to 86.3 +/- 0.5% in MS; from 79.6 +/- 4.2 to 88.9 +/- 0.5% in GS and from 85.7 +/- 1.5 to 88.4 +/- 0.8% in GD. Crude protein digestibility increased from 74.5 +/- 4.0 to 81.5 +/- 1.9% in MP; from 74.3 +/- 3.9 to 82.6 +/- 0.9% in MS; from 71.8 +/- 6.0 to 85.9 +/- 0.9% in GS and from 80.8 +/- 4.6 to 84.8 +/- 1.3% in GD between 11 and 60 weeks of age, respectively. Mean faecal moisture also increased over the growth, except in GS. Nutrient digestibility was significantly higher in large dogs at all age periods. However, larger dogs showed lower faecal scores and increased faecal moisture. In conclusion, these results show (i) an effect of age and body size on nutrients digestibility and (ii) that the lower faecal quality observed in healthy large breed dogs does not appear related to lower nutrient utilization.     

Association between average daily gain,faecal dry matter content and concentration of Lawsonia intracellularis in faeces

Background

The objective of this study was to investigate the association between average daily gain and the number of Lawsonia intracellularis bacteria in faeces of growing pigs with different levels of diarrhoea.

Methods

A longitudinal field study (n = 150 pigs) was performed in a Danish herd from day 29 to 47 post weaning. Every third day all pigs were weighed, subjected to a clinical examination and faecal samples were obtained. Faecal samples were subjected to dry matter determination and absolute quantification by PCR for L. intracellularis and porcine circovirus type 2 (PCV2). Association between average daily gain, faecal dry matter content, numbers of L. intracellularis bacteria and PCV2 genome copies in faeces was investigated in a multilevel mixed-effects linear model.

Results

Increasing numbers of L. intracellularis log₁₀ bacteria/g faeces were significantly associated with decreasing average daily gain (P < 0.001). The association was decreasing with increasing faecal dry matter content (P < 0.01). The number of PCV2 log₁₀ copies/g faeces was not significantly associated with average daily gain of the pigs (P > 0.5).

Conclusion

The results suggest a potential application of a PCR quantifying L. intracellularis in growing pigs. Faecal dry matter content must be taken into consideration in interpretation of such test results.     

Dietary carbohydrates affect caecal fermentation and modify nitrogen excretion patterns in rats. I. Studies with protein-free diets.

In a two-factorial experiment on 96 young male rats, the effects of substituting 10% raw potato starch (PS), pectins (PEC), or cellulose (CEL) for corn starch (CS) were studied using an unsupplemented protein-free (PF) diet or a PF diet supplemented either with DL-methionine or urea. The pH and the short chain fatty acids (SCFA) content in caecal digesta, as well as caecal digesta and tissue weights were determined and used as the criteria of caecal fermentation intensity. Blood urea level, amount of N excreted via faeces and urine, DAPA content, and amino acid composition of faecal protein were analyzed as indices of protein metabolism. A 10-day adaptation period to the carbohydrates fed with the casein diet preceded the experimental period of feeding the respective carbohydrates with protein-free diets. Dietary carbohydrates significantly influenced total and individual SCFA content in caecal digesta, as well as other parameters related to the intensity of fermentation. Potato starch and pectins were more intensively fermented than cellulose. Supplementation of the PF diet with methionine and urea affected only caecal isobutyric and valeric acid content in a way dependent on the carbohydrates present in the diet. Carbohydrates significantly altered the routes of N excretion. Faecal excretion was increased by all carbohydrates studied compared to corn starch, pectins had the most marked effect. Urinary excretion was significantly increased by cellulose (as compared with the PEC and PS groups) and decreased by pectins as compared with all other groups. There was an interaction between the effects of carbohydrates and type of protein-free diet on faecal and urinary excretion. The sum of amino acids in faecal protein was the lowest on the PEC diet, but the amino acid composition expressed as a per cent of total amino acid content was similar in all groups. It can be concluded that dietary carbohydrates alter the excretion patterns of endogenous nitrogen in rats in different ways and that this effect is related to the intensity of their fermentation in the hind gut.