15 years of facts and figures on veterinary disciplinary measures in the Netherlands.

In most countries, a veterinary disciplinary system is in force to ensure the quality of the veterinary profession and to offer an objective platform for complaints. We present an analysis of 15 years of veterinary disciplinary verdicts (2001-2016) to compare facts and figures and identify which factors are of major influence on the outcome of the verdicts. Rulings were collected from both paper files and the digital database of the veterinary disciplinary council (VDC), categorized, and used to create a database that enabled a statistical analysis. The results showed that complaints pertaining to companion animals are filed predominantly by owners, whereas complaints about livestock are mostly filed by the governmental civil servant (CS). CS complaints mostly address compliance issues. For the complaints made by owners (client complaints, CCs), reporting, communication, and veterinary mistakes appeared to be of statistical significance. Further studies are needed to investigate the impact of the complaints on veterinarians in general and how we can improve the veterinary disciplinary system.

Meta-analysis of effects of microbial phytase on digestibility and bioavailability of copper and zinc in growing pigs.

A meta-analysis was conducted to determine the effect of microbial phytase in pig diets on digestibility and bioavailability of Cu and Zn. Studies (n = 22) into effects of microbial phytase on digestibility and plasma levels of Cu and Zn were included in a dataset and regression analysis was performed to quantify the effect of Aspergillus niger derived 3-phytase in studies (n = 14) with a maximum dietary Zn content of 100 mg/kg and a maximum Cu addition of 20 mg/kg. Phytase inclusion increased digestibility of Zn (P = 0.003) and plasma Zn content (P < 0.001) without affecting digestibility and plasma level of Cu. Based on a comparison with dose-response studies with Zn, we estimated 500 phytase units (FTU) of microbial phytase is equivalent to 27 mg of Zn from ZnSO(4).

Phytase inclusion in pig diets improves zinc status but its effect on copper availability is inconsistent.

Complexation of dietary phytate with cations is a major cause of reduced bioavailability of Zn and possibly Cu in pig diets. We conducted 2 studies with 2 treatments in young growing pigs (8 to 40 kg) to estimate potential contributions of phytase to availability and supply of Zn and Cu, respectively. Each treatment comprised 10 pens with 8 pigs each as experimental units. In Exp. 1, 500 phytase units (FTU)/kg of microbial phytase (Natuphos 5000G; BASF) was added to a diet containing 15 mg Zn from ZnSO(4) and 160 mg/kg Cu from CuSO(4) in addition to Cu and Zn from feed ingredients. In Exp. 2, 500 FTU/kg was added to a diet containing 45 mg Zn from ZnSO(4) without added CuSO(4). Feces were collected to determine nutrient digestibility, blood was collected, and pigs were killed to determine Cu and Zn in the liver. In both experiments, phytase inclusion increased (P < 0.001) Zn digestibility by on average 10% units, serum Zn level (P < 0.001) by 0.4 mg/L, and liver Zn content (P < 0.001) by 129 mg/kg DM. In Exp. 1 phytase increased (P = 0.03) Cu digestibility by 6% units but reduced (P = 0.04) liver Cu content by 35 mg/kg DM. In Exp. 2 phytase reduced (P < 0.001) Cu digestibility by 16% units without affecting liver Cu content. Results indicate that the effect of phytase on Cu availability depends on dietary Cu and Zn content and the response variable studied. In conclusion, the consistent effects of phytase on indices of Zn status allow a reduction of Zn inclusion in phytase-supplemented diets.

Effects of crystalline amino acid supplementation to the diet on odor from pig manure.

The objective of this study was to determine the effects of specific crystalline AA supplementation to a diet on odor emission, odor intensity, odor hedonic tone, and ammonia emission from pig manure, and on manure characteristics (pH; ammonia N; total nitrogen; sulfurous, indolic, and phenolic compounds; and VFA concentrations). An experiment was conducted with growing pigs (n = 18) in a randomized complete block design, with 3 treatments in 6 blocks. Treatment groups were (1) a 15%-CP basal diet with 3 times the requirement of sulfur-containing AA (14.2 g/kg of diet, as-fed basis); (2) the basal diet with 2 times the requirement of Trp and Phe+Tyr (2.9 and 20.4 g/kg of diet, respectively, as-fed basis); and (3) the basal diet with AA supplementation to levels sufficient for maximum protein gain. Pigs with an initial BW of 41.2 +/- 0.8 kg were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 times the maintenance requirement for NE (293 kJ/kg of BW(0.75)). Feed was mixed with water at 1:2.5 (wt/wt). Feces and urine of each pig was allowed to accumulate in separate manure pits under the slatted floor. After an adaptation period of 2 wk, and after cleaning the manure pits, manure was subsequently collected. In wk 5 of the collection period, separate samples were collected directly from each manure pit for odor, ammonia, and manure composition analyses. Air samples were analyzed for odor concentration and for hedonic tone and odor intensity above the odor detection threshold. Results showed that supplementing crystalline S-containing AA in surplus of the requirement increased odor emission (P < 0.001) and odor intensity (P < 0.05) and reduced odor hedonic tone (P < 0.05) from the air above the manure pits. Supplementing crystalline Trp, Tyr, and Phe in surplus of the recommended requirements did not affect odor emission, odor intensity, or odor hedonic tone. Regardless of dietary treatment, all pigs had similar performance levels. No differences were observed in ammonia emission from manure of pigs fed different levels of AA supplementation (P = 0.20). To reduce odor from pig manure, dietary S-containing AA should be minimized to just meet the recommended requirements.

Effects of dietary crude protein level on odour from pig manure.

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, hedonic tone, and ammonia emission from pig manure and on manure composition (pH, total nitrogen, ammonium, volatile fatty acids, indolic, phenolic and sulphur-containing compounds). An experiment was conducted with growing pigs (n = 18) in a randomised complete-block design with three treatments in six blocks. Treatment groups were 12%, 15% and 18% CP diets. Barley was exchanged for soya-bean meal. Crystalline amino acids (AA) were included in the 12% CP diet up to the level of pigs' requirement; the same amount of AA was added to the 15% and 18% CP diets. Pigs with an initial body weight (BW) of 36.5 ± 3.4 kg (mean ± s.d.) were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 × maintenance requirement for net energy (NE: 293 kJ/kg BW0.75). Feed was mixed with water, 1/2.5 (w/w). Faeces and urine of each pig were accumulated together in a separate manure pit under the slatted floor. After an adaptation period of 2 weeks, the manure pits were cleaned and manure was collected. In the 5th week of the collection period, air samples for odour and ammonia analyses, and manure samples were collected directly from each manure pit. Air samples were analysed for odour concentration and for hedonic value and intensity above odour detection threshold. Manure samples were analysed for volatile fatty acids, and indolic, phenolic and sulphurous compounds, ammonium and total nitrogen concentrations. Reducing dietary CP from 18% to 12% lowered odour emission ( P < 0.05) and ammonia emission ( P = 0.01) from pig manure by 80% and 53%, respectively. Reduced dietary CP decreased total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 4-ethyl phenol, indole and 3-methyl indole concentrations in the manure ( P < 0.05). Volatile fatty acids and cresols concentrations in the manure of pigs fed different dietary CP levels were similar. A reduction of dietary CP and at the same time providing essential AA is an option to reduce odour emission as well as ammonia emission from pig manure.

Effect of graded doses and a high dose of microbial phytase on the digestibility of various minerals in weaner pigs.

An experiment with 224 weaner pigs (initial BW of 7.8 kg) was conducted to determine the effect of dose of dietary phytase supplementation on apparent fecal digestibility of minerals (P, Ca, Mg, Na, K, and Cu) and on performance. Four blocks, each with 8 pens of 7 pigs, were formed. Eight dietary treatments were applied to each block in the 43-d experiment: supplementation of 0 (basal diet), 100, 250, 500, 750, 1,500, or 15,000 phytase units (FTU) or of 1.5 g of digestible P (dP; monocalcium phosphate; positive control) per kilogram of feed. The basal diet, with corn, barley, soybean meal, and sunflower seed meal as the main components, contained 1.2 g of dP per kilogram of feed. Fresh fecal grab samples were collected in wk 4 and 5 of the experiment. Average daily feed intake, ADG, G:F, and digestibility of all of the minerals increased (P < 0.001) with increasing phytase dose. Digestibility of P increased from 34% in the basal diet to a maximum of 84% in the diet supplemented with 15,000 FTU, generating 1.76 g of dP per kilogram of feed. At this level, 85% of the phytate phosphorus was digested, compared with 15% in the basal diet. Compared with the basal diet, digestibility of the monovalent minerals increased maximally at 15,000 FTU, from 81 to 92% (Na) and from 76 to 86% (K). In conclusion, phytase supplementation up to a level of 15,000 FTU/kg of a dP-deficient diet improved performance of weaner pigs and digestibility of minerals, including monovalent minerals. Up to 85% of the phytate-P was digested. Thus, dietary phytase supplementation beyond present day standards (500 FTU/kg) could further improve mineral use and consequently reduce mineral output to the environment.

Performance of male pigs immunized against GnRH is related to the time of onset of biological response.

In this study, the performance of male pigs immunized against GnRH was determined in relation to the onset of their biological response to the immunization. Pigs were immunized at 9 and 17 wk of age and were housed in a pen together with both a surgically castrated and an intact boar littermate. Feed intake was restricted to 2.8 to 3.2 times maintenance requirement for energy. Animals were weighed weekly and slaughtered at 108 kg BW. Depending on the time of onset of the response after immunization in terms of biological effects, immunized pigs were retrospectively grouped into two categories. One category consisted of the immunized pigs, which had undetectable or low levels of LH and testosterone at the time of booster immunization-known as "early" responding immunocastrates (E-IM, n = 8), whereas the "late" responding immunocastrates (L-IM, n = 7) had substantial LH and testosterone levels at that time. This dichotomy of the response to immunization also was reflected in testis weight, with 17 g and 40 g for E-IM and L-IM pigs, respectively. At slaughter, testis size and weight were reduced (P < 0.001) in the immunocastrated pigs as compared to the intact boars. Androstenone concentrations in backfat of all immunocastrated pigs were undetectable. Growth performance (i.e., ADG and feed efficiency [FE, g gain/kg feed]), was better in boars and L-IM pigs than in surgical castrates and E-IM pigs (P < 0.05). Average daily gain and FE did not differ between E-IM pigs and the surgical castrates, but intact boars performed better than L-IM (P < 0.02). There were no significant differences in carcass quality (backfat thickness and meat percentage) between boars and surgical castrates at slaughter. However, for both characteristics L-IM pigs and intact boars performed better (P < 0.03) than E-IM pigs. Thus, growth performance in L-IM is better than in either E-IM or surgical castrates.

Nutritive value of the meat and bone meals from cattle or pigs in broiler diets.

The nutritive value of meat and bone meals (MBM) was assessed for broilers. The MBM was produced according to the revised (pressure) processing system ordered by the European Union (EC 96/449). Three batches of MBM from cattle (MBMcattle) and three from pigs (MBMpig) with different ash contents (224, 306, 387, and 209,293, 430 g/kg, respectively) were tested for digestibility at a 10% inclusion level. The MBMcattle and MBMpig with the lowest ash (224 and 209 g/kg, respectively) were tested also at 20% inclusion. A basal diet (corn-soybean meal) was used as a control. Two-week-old broiler chickens were used in four replicates per treatment (14 to 32 d of age). The AMEn of MBM was high (10.51 to 13.04 MJ/kg DM). Species origin had no significant effect, whereas more ash and a higher inclusion level decreased the AMEn. The factors investigated showed no significant effect on the excretal digestibility of CP or on total AA. Excretal digestibility of total amino acids (AA) ranged from 60 to 65%. The ileal digestibility of CP and AA of MBMpig with 209 g/kg ash was also tested at 10 and 20% inclusion. Excretal digestibility was significantly higher than ileal digestibility of CP (63.8 and 55.8%, respectively) and total AA (60.9 and 56.2%, respectively). The 20% inclusion level resulted in a lower digestibility for both methods. The digestibility of CP was measured by four different in vitro techniques, based on pepsin digestibility. The data showed a large variation and did not correlate at all with the in vivo digestibility values.

[Organic pig farming: what about parasitic infections?]. / Biologische varkenshouderij: hoe staat het met de parasitaire infecties?

The parasitological problems that may arise in organic pig farming are discussed. The rearing of pigs outdoors increases substantially the chances that several parasite species will complete their life cycle. Moreover, zoonoses may play an important role. Parasite species that may cause problems are discussed, as are control measures, when possible.

The effects of calcium benzoate in diets with or without organic acids on dietary buffering capacity, apparent digestibility, retention of nutrients, and manure characteristics in swine.

Eight barrows (Yorkshire x [Finnish Landrace x Dutch Landrace]), initially 30 kg BW, were fitted with ileal cannulas to evaluate the effects of supplementing Ca benzoate (2.4%) and organic acids (OA) in the amount of 300 mEq acid/kg feed on dietary buffering capacity (BC), apparent digestibility and retention of nutrients, and manure characteristics. Swine were allotted in a 2 x 4 factorial arrangement of treatments according to a cyclic (8 x 5) changeover design. Two tapioca-corn-soybean meal-based diets were formulated without and with acidogenic Ca benzoate. Each diet was fed in combination with OA (none, formic, fumaric, or n-butyric acid). Daily rations were equal to 2.8 x maintenance requirement (418 kJ ME/BW(.75)) and were given in two portions. Chromic oxide (.25 g/kg) was used as a marker. On average, Ca benzoate lowered BC by 54 mEq/kg feed. This salt enhanced (P < .05) the ileal digestibility (ID) of DM, OM, arginine, isoleucine, leucine, phenylalanine, alanine, aspartic acid, and tyrosine (by up to 2.4 percentage units). Also, the total tract digestibility (TD) of DM, ash, Ca and GE, and Ca retention (percentage of intake) was greater (P < .05) in swine fed Ca benzoate, whereas N retention remained unaffected. Addition of all OA (formic and n-butyric acid, in particular) exerted a positive effect (P < .05) on the ID of amino acids (except for arginine, methionine, and cysteine). A similar effect (P < .05) was found for the TD of DM, OM, CP, Ca and total P and for the retention of N and Ca. In swine fed Ca benzoate, urinary pH decreased by 1.6 units (P < .001). In conclusion, dietary OA have a beneficial effect on the apparent ileal/total tract nutrient digestibilities, and Ca benzoate increased urine acidity, which could be effective against a rapid ammonia emission from manure of swine.

Effects of dietary carbohydrates and buffering capacity on nutrient digestibility and manure characteristics in finishing pigs.

A 2 x 3 factorial experiment was conducted with 24 finishing pigs (Yorkshire x [Finnish Landrace x Dutch Landrace]) to determine the effects of dietary buffering capacity (BC) and carbohydrate sources on apparent total tract digestibility (TD), N retention, and manure characteristics. Twelve of these pigs were fitted with steered ileo-cecal value cannulas to measure the apparent ileal digestibility (ID) of N. Experimental variables were two levels of BC (High = 600 mEq/kg and Low = 530 mEq/kg) and three dietary carbohydrates (tapioca [28%], soybean hulls [25%], and sugar beet pulp [25%]). The two levels of BC were achieved by adjusting the amounts of alkalogenic limestone and acidogenic Ca sulfate in the diet. Pigs were fed twice daily at 2.4 x maintenance requirement for metabolizable energy (418 kJ ME/BW(0.75)). Chromic oxide was used as an indigestible marker. Feces and urine were collected over 5 d for nutrient balance and in vitro measurements of pH and ammonia emission over 7 d. No significant interactions between BC and dietary carbohydrates on the ID, TD, N retention, or manure characteristics were observed. Lowering BC with Ca sulfate did not affect digestibility of most nutrients, except for a negative impact on the TD of Ca (P = 0.015) and Mg (P = 0.003). Although all pigs receiving Ca sulfate had more acidic urine (by 0.49 pH units; P = 0.001), ammonia emission from manure was not lowered, irrespective of the carbohydrate source. Carbohydrates affected significantly the ID and TD of most nutrients, whereas N retention remained similar (P > 0.10). Urinary N:fecal N ratios in manure of pigs fed diets with tapioca, soybean hulls, and beet pulp were 2.09, 1.35, and 1.67, respectively. These ratios corresponded with in vitro ammonia emission (169, 125, and 148 mmol/7 d; P = 0.023). In conclusion, these results indicate that the acidification of urine in pigs fed Ca sulfate in the presence of NSP-rich carbohydrates was achieved. However, acidity of manure and ammonia emission were not affected. The addition of NSP from soybean hulls and(or) sugar beet pulp reduced ratios of urinary:fecal N, and thereby ammonia emission.

Quantification of inositol phosphates using (31)P nuclear magnetic resonance spectroscopy in animal nutrition.

A (31)P NMR method for quantitative determination of inositol phosphates in simple incubation samples of sodium phytate and Aspergillus niger phytase and in different types of complex samples, such as diets, digesta, and feces, is described. The inositol phosphates in complex samples were extracted with HCl, concentrated, and purified using freeze-drying and filtration and subsequently determined at pH 12.6 in aqueous solution using a (31)P NMR method. The (31)P NMR technique has as its main advantages over the HPLC techniques that it does not necessitate standards that may cause background matrix effects and that the spectra of inositol phosphates and orthophosphate appear in the same run without further sampling errors. The results of inositol hexaphosphate analysis with HPLC can be confirmed by this (31)P NMR method. Contents of inositol tetra-, tri-, di-, and monophosphate in the biological samples appear to be quantitatively not important. The (31)P NMR method can be applied for use in animal nutrition in general and studies of using phytase in diets for farm animals in particular, by measuring the content of inositol phosphates in feed ingredients, complete feeds, ileal contents, and feces of pigs and poultry.

Effect of the ratio between essential and nonessential amino acids in the diet on utilization of nitrogen and amino acids by growing pigs.

In 36 growing pigs (30 to 60 kg), N balance and amino acid (AA) composition of weight gain were measured to evaluate the interactive effect of the ratio between N from essential amino acids (EAA(N)) to nonessential amino acids (NEAA(N)) and total N level (T(N)) in the diet on N retention and utilization of N, EAA(N), NEAA(N), and AA. Nine diets composed from ordinary feedstuffs and supplemented with crystalline AA were used (three EAA(N):NEAA(N) ratios of 38:62, 50:50, and 62:38 at three T(N) levels of 18.8, 22.9, and 30.0 g/kg). Pigs were fed restrictedly, at a level of 2.8 x energy for maintenance. In all diets, EAA (including arginine) supply was according to or slightly above the recommended ratios to lysine. Measurements were done in four blocks of nine pigs each. In a concomitant slaughter experiment, the AA composition of deposited body protein was determined to estimate AA utilization. The effects of T(N) and EAA(N):NEAA(N) and their interaction for N retention and utilization were significant. Nitrogen retention increased with higher T(N) in the diet. Increasing EAA(N):NEAA(N) from 38:62 to 50:50 improved N retention only at the two lower T(N) levels. Increasing EAA(N): NEAA(N) above 50:50 failed to improve N retention significantly at any of the three T(N) levels. Lowering T(N) improved the utilization of total and digested N and of EAA(N) and NEAA(N). The increase in EAA(N): NEAA(N) consistently resulted in a lower utilization of EAA(N), but this was compensated by a higher utilization of NEAA(N). The utilization of T(N) was improved by increasing EAA(N):NEAA(N) from 38:62 to 50:50 at the two lower T(N) levels and was relatively unaffected by EAA(N):NEAA(N) at the highest T(N). However, a lower utilization of N was observed at a ratio of 62:38 at a T(N) level of 22.9 g/kg. The effects were similar for utilization of individual EAA and NEAA. Utilization of alanine, aspartic acid, and glycine was close to or >100% at the highest EAA(N):NEAA(N), which was expected because all of these AA are synthesized in pigs. Also, the utilization of arginine was >100% in most of the treatments, which confirms the semiessential character of this AA for maintenance. We concluded that the required ratio of EAA(N):NEAA(N) for optimal N retention and utilization is approximately 50:50. The EAA(N):NEAA(N) is more important at lower dietary protein levels. This study indicates that EAA(N): NEAA(N) can be increased up to 70:30 without lowering the utilization of N. Thus, deaminated EAA(N) was efficiently utilized for the synthesis of NEAA(N).

Environmental concerns about animal manure.

The structure of swine production has changed dramatically in the last four decades. Raw materials for swine feeds are often grown in regions other than where swine production takes place. Swine manure is mostly spread in the neighborhood of the facilities, which may lead to soil accumulation of minerals such as P, Cu, and Zn. Moreover, soil nitrate may leach and result in enhanced nitrate levels in ground and surface water. Large swine units generate odors, ammonia, and dust that can exceed tolerable levels. Negative effects of swine production on the environment have already led to new legislation that limits the use of animal manure or the expansion or localization of pig operations in some countries. The consequences of intensive swine production on the environment and possible solutions by means of nutrition are outlined. Also, discussed are experiences from the Dutch situation, forthcoming legislation, and environmental constraints on pig production in the future. Our approach centers more on the system level.

Non-starch polysaccharides in pig feeding.

In pigs and humans, the nutrients starch, protein, fat and some minerals need to be digested prior to the terminal ileum for optimal use of these nutrients. In contrast, the non-starch polysaccharides (NSP) are mainly fermented by microbes in the hindgut. Results of experiments in pigs showed that NSP negatively affected apparent digestion of protein, fat and some minerals. In addition, large amounts of fermented NSP increased the empty weight of the hindgut. Because tissue of organs like the intestinal tract are metabolically very active, it may have required more energy for maintenance, hence leaving less energy for growth. Despite all the negative effects as mentioned above, including NSP-rich ingredients in pig diets also has quite a lot of advantages. Their energy supply can cover the energy requirements for maintenance. In addition, positive effects on the well-being and health of pigs, and on the excretion of ammonia are claimed. In conclusion, in future pig diet formulation not only the nutritional aspects of NSP-rich ingredients should be taken into account, but also their non-nutritional aspects. This might be realized by developing nutrient based feed evaluation systems, rather than the energy based systems which are presently used.

Effect of dietary vitamin E supplementation on pork quality.

The purpose of this experiment was to examine the effect of dietary vitamin E supplementation on pork quality, and in particular on colour stability. Crossbred pigs (n = 72) at a mean weight of 44 kg were assigned to one of two treatments. One group received, during a period of 84 days prior to slaughter, a tapioca based diet, which contained 8 mg vitamin E per kg feed. The other group received during this period the same diet, except it was supplemented with 200 mg vitamin E per kg feed. Muscle samples of longissimus thoracis and lumborum (LL) and psoas (PM) were collected at 24 hr post mortem and meat quality was assessed: pH, drip and cooking loss, shear force and intramuscular fat content. Colour stability was evaluated in fresh muscle (LL and PM) and after freezing (LL only) by measuring redness (a(∗)-values) during 6 days of storage at 7 °C. TBA-values and microbiological counts were also determined during storage. Results showed that extra dietary vitamin E had no effect on pig performance (daily gain, feed efficiency, lean meat percentage) nor on meat quality traits. The vitamin E levels were five times higher in the muscles of the treated group than the control group. In comparison with fresh LL muscle, colour stability was lower in PM and after freezing. In both muscles, the vitamin E treatment reduced TBA-values, in particular after frozen storage. No effect was found on microbiological counts. Colour stability was improved in LL after 6 days of storage, but not in PM. The effect in LL is too late to be of practical significance, since pork is usually sold well before that time in The Netherlands. It is suggested that variation in feedstuff composition of the diet may possibly explain part of the variable results reported in literature for the effect of vitamin E supplementation on colour stability of pork.

Impact of nutrition on reduction of environmental pollution by pigs: an overview of recent research.

This paper focuses on research with pigs carried out primarily at the ID-DLO in the Netherlands with the aim to reduce environmental pollution with nitrogen and phosphorus by changing the diet of the animals while maintaining their health and performance. The excretion of phosphorus (P) per growing pig has been more than halved in the last 20 years as a result of intensive nutritional research on P digestibility, requirements for P, and on the efficacy of microbial phytase in pig feeds. Also, nitrogen (N) excretion can be reduced substantially, but this knowledge has not been put into practice as yet. Preliminary results show that ammonia production can be reduced considerably by altering the diet. Studies to reduce the overproduction of sow manure (up to 98% water) showed that voluntary water consumption by non-pregnant sows under thermal neutral conditions was approximately 1.4 higher than the requirements. A water:feed ratio of 2:1 for pregnant sows kept at an ambient temperature of 18-20 degrees C had no detrimental effect on health and nutrient digestibility, but diminished urine production by 3.6 L/day, as compared to that with ad libitum water consumption.

Effect of resistant starch on net portal-drained viscera flux of glucose, volatile fatty acids, urea, and ammonia in growing pigs.

Net portal-drained viscera (PDV) flux of glucose, VFA, ammonia, and urea was determined in pigs fed diets with or without resistant starch. Diets consisted of 65% cornstarch (diet CS), 32.5% cornstarch and 32.5% raw potato starch (diet CPS), or 65% raw potato starch (diet PS); the remaining 35% supplied all amino acids, fat, fiber, minerals, and vitamins. The diets contained twice the maintenance requirement for energy and were fed twice daily to four barrows (initial BW 56 kg) in three periods in a crossover design. The pigs were fitted with catheters in a mesenteric vein, a mesenteric-artery, and the portal vein, and net PDV flux was calculated by multiplying portal-arterial concentration differences and corresponding portal vein flow. Net PDV flux of glucose was significantly less after feeding diets CPS and PS, and portal absorption of ileally digested glucose was 89, 66, and 41% for diets CS, CPS, and PS, respectively. Net PDV flux of VFA was lowest after feeding diet CS and three to four times higher after feeding diets CPS and PS. Net PDV flux of ammonia was highest for diet CS and almost halved after feeding diets CPS and PS. There was a small negative net PDV flux of urea for diets CS and CPS, which significantly increased after feeding diet PS. These results suggest that excretion of nitrogen is shifted from urine to feces primarily by reduction of the net PDV flux of ammonia when resistant starch is fed.