Studies on the secretion of amino acids and of urea into the gastrointestinal tract of pigs. 3. Secretion of urea determined by continuous intravenous infusion of 15N-urea

Three pigs, of 34 kg live weight, were each fitted with re-entrant cannulas both in the duodenum and terminal ileum and catheters in the jugular vein and in the carotid artery. Pigs received a diet based on wheat and dried skimmed milk in equal amounts at 12 h intervals. During the preliminary period the digesta flowing from both duodenal and ileal cannulas were collected over 12 h after feeding on two consecutive days and half of them were reintroduced into the gut and half were stored at -20 degrees C. During the experimental period 15N-urea was infused into the jugular vein for 12 hours starting with the morning meal. Total amount of urea infused was 5 g containing 1.22 g 15N-excess. The digesta from both proximal duodenal and ileal cannulas were collected and stored, while the digesta from the preliminary period were reintroduced into the respective distal cannulas. Blood samples were taken at different time of infusion. At the end of infusion period the animals were sacrificed and samples of the contents of the digestive tract and tissues were taken. Urea flux calculated according to atom-% 15N-excess of urea N in plasma was 1.23 to 2.37 g/kg body weight/day. In the duodenal digesta 94.5 +/- 0.2 and in ileal digesta 57.1 +/- 7.39 per cent of 15N were in the TCA soluble fraction. The total amount of 15N in the duodenal digesta was 1.7 to 6.3 times greater than in the ileal digesta. Only small amount of 15N was found in the caecum and almost none in the contents of colon and rectum. It is concluded that urea is secreted into all parts of the digestive tract, the main sites of urea secretion being pancreatic juice and/or bile as well as the small intestine. The total amount of urea secreted is assumed to be similar to the daily urea excretion.     

Endogenous nitrogen metabolism in 15N-labeled swine. 1. Course of 15N-labeling and 15N excretion in urine and feces under 4 different diets

Four male castrated pigs (55-65 kg) either received a wheat--fish meal diet (1 and 2) or a wheat--horse bean diet (3 and 4) without straw meal supplement (1 and 3) or with a supplement of 20% DM partly hydrolysed straw meal to the DM of the ration (2 and 4). In order to investigate whether a 15N-labelling of the pigs is also possible with a protein excess in the ration, the animals 1 and 2 received 24.8 g and the animals 3 and 4 = 11.6 g crude protein/kg0,75 live weight. During a 10-day 15N-labelling 385 mg 15N-excess (15N') per kg0,75 were applied in a mixture of ammonia acetate and ammonia chloride in the feed. During the period of 15N-labelling the following quotas of the applied 15N-amount were incorporated: 1 = 10.2%, 2 = 7.2%, 3 = 18.7%, 4 = 14.4%. 15N-excretion in both TCA fractions of faeces showed a highly significant positive correlation to the increasing content of crude fibre in the 4 diets. The immediate 15N-incorporation into the TCA-precipitable fraction of faeces (from the 2nd of the beginning of the 15N-application onwards) proves that 15N enters the large intestine endogenously (probably as 15N-urea) and serves bacterial protein synthesis. Three days after the last 15N-application the pigs were killed. The following values of atom-% 15N' could be determined in the TCA-precipitable blood plasma and in the TCA-precipitable fraction of the liver: 1 = 0.18 and 0.19 resp., 2 = 0.22 and 0.27 resp., 3 = 0.22 and 0.23 resp. and 4 = 0.24 and 0.26 resp. The other examined organs and tissues showed smaller differences between the test animals. The following atom-% 15N' were measured in the TCA-precipitable fractions on an average of the 4 test pigs: kidney = 0.20, pancreas = 0.18, intestinal wall tissue, duodenum = 0.18, jejunum (beginning) = 0.17, jejunum (end) = 0.15, ileum = 0.15, caecum = 0.16, colon (beginning) = 0.15, colon (middle) = 0.14, colon (end) = 0.13, stomach (cardia) = 0.11, stomach (fundus) = 0.12, spleen = 0.13, heart = 0.12, skin = 0.07 and skeleton muscles = 0.06. The results show that the 15N-labelling of tissues and organs of pigs is also possible at a high level of protein supply by means of an oral application of 15N ammonia salts.     

Nitrogen metabolism in the large intestine of ruminants. 3. Microbial utilization of intracecally administered 14C- and 15N-marked urea in the large intestine of sheep in simultaneous intracecal administration of partially hydrolyzed straw meal

Two experiments were performed on sheep, receiving on maintenance level a pelleted straw ration high in crude fibre (straw, 70.5%; dried sugar beet pulp, 12%; cereals, 10%; urea, 2%; ammonium hydrogen carbonate, 3%; minerals 2,5%). The animals were fitted with ileo-caecal re-entrant cannulas. The effects of the introduction of HC1-partly hydrolysed straw meal into the digesta of the large intestine on the digestion processes in that segment were studied. Under these conditions the metabolism of 14C and 15N labelled urea, which was given into the caecum, was estimated. In experiment 1 (E 1; 2 animals) unlabelled, precollected digesta were hourly reintroduced together with 14C and 15N labelled urea via the caecal cannula. In experiment 2 (E 2; 3 animals) the digesta were supplemented with partly hydrolysed straw meal (10% of the mean daily DM-intake with the ration). The supplement of partly hydrolysed straw meal caused an increase of the 15N excretion with faeces from 13.4% (E 1) to 19.8% (E 2) of the dose. The 15N was mainly incorporated in the bacterial fraction (98% E 1; 96% E 2). As a reason for the increased 15N incorporation into the bacterial fraction of 106.4 mg15N' in E 2 vs. 67.3 mg15N' in the experiment without straw meal supplement the higher supply of energy as fermentable carbohydrates was assumed.     

Studies on in vitro degradation and in vivo digestion of a slow ammonia releasing urea product

a slow ammonia releasing urea product (Uromalt) has been produced by autoclaving and drying of germinated barley and urea. In vitro degradability of nitrogen (IVDN, Raab et al., 1983) was in average 62 +/- 9% in 4 hours, compared to 76 +/- 8% with an autoclaved and dried mixture of urea and not-germinated barley. Mixtures of urea with Leucaena l. or Azadarichta indica (Neem cake) showed degradabilities of about 80 and 93%, respectively, when dried at 39 degrees C, but of 65% when dried at 100 degrees C. For comparison, degradabilities of proteins of ground nut, guar, sunflower, mustard, rape and sesame cake/meal have been determined. When growing lambs were fed a ration containing 15% Uromalt, faecal N-excretion was significantly higher on the expense of urinary N-excretion, compared with groups fed isonitrogenous rations containing soya bean meal with or without urea and molasses. N-retention was not significantly affected. It is concluded that this slow ammonia releasing urea product can be used in cases where molasses or other feedingstuffs rich in rapidly fermentable carbohydrates are not available.     

Studies with 15N-labeled lysine in colostomized hens. 1. 15N excretion in urine

0.2% L-lysine with an atom-% 15N-excess (15N') of 48% were given per day through a throat probe in an experiment to three colostomised laying hybrids in addition to a pelleted ration of 120 g per animal and day. In the following 4 days unlabelled L-lysine was given. As the labelled lysine was given three times a day, the development of 15N'-excretion could be pursued. 80 minutes after the 15N'-lysine dose a distinct atom-% 15N' could be detected in urine. 6 hours after the 15N'-application we rediscovered 2.9% (hen 1), 4.2% (hen 2) and 2.7% (hen 3) of the applied 15N'-amount in urine. 8 days after the beginning of the experiment the excretion of 15N' in urine averaged 17.5% of the consumed 15N'-amount. 44% of the nitrogen in the ration, however, was excreted in urine. The results showed that the lysine-N is excreted to a considerably lower extent in urine than the nitrogen in the remaining ration.     

The effect of straw meal on the crude protein and amino acid metabolism and digestibility of crude nutrients in broiler hen breeds. 1. Problems, experimental review and N-excretion in the urine

The metabolization of the straw N and the influence of the straw on N excretion in urine were studied in 2 experiments with colostomized broiler hens and with 15N labelled wheat straw as well as 15N labelled wheat. In experiment 1 the test animals divided up into 4 groups received 0 g, 20 g, 30 g and 40 g straw meal per animal and day in addition to 120 g mixed feed. The daily 15N-excess (15N') intake from the straw was 18.4 mg, 27.5 mg and 36.7 mg. The amount of 15N' daily consumed with the labelled wheat in experiment 2 was 119.7 mg. 40 g straw meal resulted in a significantly increased amount of urine (p less than 0.05). The amounts of urine N and uric acid N were only increased as a tendency. On average the productive N decreased as a consequence of the straw meal supplement from 1070 mg/animal and day (control) to 764 mg/animal and day after 40 g straw meal supplement. The productive 15N' of the labelled wheat was not influenced by the straw meal supplement. The productive 15N' of the straw increased from 3.8 mg/animal and day (20 g straw) to 13.4 mg/animal and day (40 g straw). In contrast to 15N wheat, straw as a 15N source resulted in a lower labelling of uric acid N in comparison with urine N. It can be assumed that the changed metabolization of the straw N is influenced by microbial processes in the intestines.     

Studies on nitrogen metabolism in the large intestine of ruminants. 5. Metabolism of intra-cecally infused 15N-urea without and with fermentable material in heifers

Six heifers with a live weight of 215, 227 and 238 kg (experiment 1) and 220, 227 and 233 kg, resp. (experiment 2), were supplied with ileocaecal re-entrance cannulae, jugular venous catheters and bladder catheters. The ration consisted of 4 kg maize silage and 4 kg wheat straw pellets per animal per day. Up to 3.5 kg of the straw pellets, consisting of 73% wheat straw, 10% barley, 12% molasses, NPN salts and a mineral mixture, were consumed per animal per day. In a preliminary period 50% of the digesta flow was collected over 12 h/d on 5 consecutive days and stored in a deep-freeze. During the main trial the re-entrance cannula was disrupted and the flowing digesta were quantitatively collected at the end of the ileum; previously collected digesta were supplemented with 15N urea and every hour over 24 h infused into the caecal part of the re-entrance cannula. Between the 24th and 30th hours the digesta were infused without 15N urea supplement. In trial 2 the digesta were also supplemented with partly hydrolysed straw meal between the 1st and 30th hours (approximately 10% straw meal DM related to digesta DM). There were no differences between trials 1 and 2 with regard to the increase of atom-% 15N excess (15N') in the plasma urea. The 15N labelling decrease of the plasma urea N shows that the half-life is 7.9 h in trial 1 and 7.0 h in trial 2. The NH3 nitrogen in faeces was distinctly higher labelled in trial 2 after the supplement of straw meal than in trial 1. The total N in faeces was also twice as highly labelled as in trial 1. Atom-% 15N' in urine was significantly higher in trial 2 than in trial 1 between the 6th and 16th hours after the beginning of 15N urea supplementation. In the decrease curve of atom-% 15N' (after the 26th hour of trial) the values in trial 1 were generally higher than in trial 2. The higher bacterial protein synthesis in the large intestine in trial 2 (after the supplement of partly hydrolysed straw meal) had the effect that 13.6% of the supplemented 15N' was excreted in faeces by the 30th hour of trial, in contrast to this only 4.7% in group 1. Up to the 4th day after the 15N urea infusion these values increased to 16.2 and 6.1%, resp., only.     

Effect of the content of crude plant protein in the ration on the utilization of urea in dairy cattle. 2. 15N-urea metabolism

The metabolism of 15N-urea in the rations of dairy cows was investigated in dependence on the crude protein content of the rations. With energy concentration remaining unchanged, the rations contained 10.7 (I), 13.7 (II) and 17.1 (III)% plant crude protein and, after the supplementation of 150 g urea per animal and day, a total of 13.8, 16.7 and 20.2% crude protein in the dry matter. The urea was intraruminally infused during the feeding in the morning and the evening. In the morning feeding of each 1st measuring day it was labelled with 27.5 atom-% 15N-excess (15N'). The degree of labelling with 15N' of the N-fraction of rumen fluid, contents of the duodenum, faeces and milk, precipitable with trichloric acetic acid (TCA) decreased with the rising protein level of the ration. This effect was bigger than could be expected considering the low 15N'-quota in the total-N of the ration. In the sequence I ... III, 52.7, 32.2 and 30.6% of the 15N'-amount taken in passed the duodenal re-entrant cannula in TCA-precipitable form within 72 hours after the 15N-application. 33.3, 21.9 and 22.6% were apparently absorbed in the intestines as TCA-precipitable N within 120 h after the 15N'-application. In the same period 31.7, 43.1 and 72.8% of the 15N' taken in were excreted in urine. 12.3, 9.6 and 5.8% of the applied 15N' were found in milk protein. One can conclude that the utilisation of urea-N decreases with the rising level of crude protein in the ration and that, however, urea-N is still biochemically utilised when there is an excess of plant-N in the ration.     

Urea utilization of growing lambs. 2. Growth experiments

In two growth experiments with 30 lambs per group the influence of urea (1-2% of the ration) and straw (20-30% of the ration) on the performance was studied under conditions of intensive fattening. The content of native crude protein in the rations varied between 10.1 and 18.4% of the DM. In experiment 1 the lambs of the two groups which received mixed feed for fattening lambs without urea on average consumed with 1.02 and 1.11 kg DM resp., 696 and 757 EFUcattle resp. and 173 and 189 g crude protein resp. per animal and day. The groups with wheat or barley and urea consumed 1.06 and 0.96 kg DM resp., 714 and 627 EFUcattle resp. and 209 and 155 g crude protein resp. Their weight gain of 247 g/animal and day was 24% and that of 230 g resp. 26% higher than that in the control groups without urea. The lowest dry matter intake (0.91 and 0.82 kg resp.) was shown by the animals of the groups which received wheat or barley without urea. In the second experiment the control group achieved an average daily weight gain of 327 g at an expenditure of 2.24 kEFUcattle/kg weight gain. Despite a partly higher dry matter intake, the daily EFUcattle intake was between 12.2 and 24.5% lower in the straw groups and energy expenditure increased between 12.0 and 27.8%. Urea supplements of between 1 and 2% improved dry matter, EFUcattle and crude protein intake and thus weight gain.     

Nitrogen exchange in the large intestine of ruminants. 4. Exchange and isotope balance of intracecally administered 14C- and 15N-urea in sheep with simultaneous intracecal dose of a partly hydrolyzed straw meal

Two experiments were performed with wethers (Body weight 34 to 44 kg) receiving a ration rich in crude fibre at maintenance level. The animals were fitted with ileocaecal cannulas into which 14C-, 15N-labelled urea together with digesta was introduced hourly for a 24 hours period (V1; 2 animals). In experiment two (V2; 3 animals) in addition HCl-partly hydrolysed straw meal was introduced. After ureolytic degradation the intracaecal applied urea entered mainly the intermediary metabolism. The resulting ammonia was resynthesized to urea without any time lag. The rate constant for the increase in 15N labelling of urea was 3.2 d-1 in both experiments. Urea leaves the plasma with half lives of 10.6 (V1) and 5.2 (V2) hours. More than 60% of the applied urea were excreted with urine. Formed 14CO2 appeared at proportions of 66% (V2) and 71% (V1) in the respiration gases. Both, the decline of the 14C-activity in blood plasma and the specific 14C-activity of CO2 in the respiration gases after the end of the labelling period do not follow a kinetic of first order. The 15N-labelling of the NH3-N in ileal digesta was very high and reached plateau values similar with those of plasma urea (2.54 vs. 2.56 atom-% 15N-excess). A direct entry of plasma urea into the small intestine was concluded.     

Endogenous nitrogen metabolism in 15N-labeled swine. 3. Endogenous excretion of 15N- and 14C-labeled secretions following a 14C-leucine injection

Four pigs (59-65 kg live weight) were labelled over a period of 10 days with 15N in the feeding of a fishmeal diet (1), a fishmeal diet + partly hydrolysed straw meal (2), a horse bean diet (3) and a horse bean diet + partly hydrolysed straw meal (4). After a 24-hour fasting the animals were provided with simple cannulae in the upper part of the small intestines. After a fasting period of 24 h all four pigs received a 14C-leucine injection and the cannula secretion was collected in the subsequent 24 h. After the feeding of the diets without straw meal supplement (1 and 3) there were distinct differences in the secretion in comparison with the feeding with straw meal supplements (2 and 4) despite the long fasting period (48-72 h). 14C-activity could already be detected in the TCA-precipitable fraction of the secretion after 3-6 min of the injection in 1 and 3 but only 20 to 25 min after the 14C-leucine injection in 2 and 4. The specific 14C-leucine activity of the TCA-soluble fraction of the secretion was, after the straw meal supplementation to the fish meal diet, 15 times higher 25 min after the 14C-leu-injection, 25 times higher after 70 min, 36 times after 2 h and 1.8 times after 4 h than without straw meal supplementation. For all four diets a specific correlation (r = 0.96) could be ascertained between the increase of 14C-activity/mg N in the TCA-soluble fraction and the increasing crude fibre content in the diet between 25 and 180 min after the injection. Furthermore, a distinctly decreased N-secretion/h could be ascertained (correlation coefficient r = 0.84) with the increasing crude fibre content in the diet. The influence of the crude fibre on the parameters mentioned is seen in the changed osmotic conditions in the secretion, which may be caused by the changed regulation by hormones of the gastro-intestinal tract. The atom-% 15N' in both TCA-fractions of the secretion underwent big rhythmic variations, which is explained by different ratios of the components pancreatic juice, bile, and intestinal juice.     

Nitrogen metabolism in the large intestine of ruminants. 6. Metabolism of intracecally administered 14C and 15N urea in sheep with simultaneous intracecal doses of heat-damaged hay

Two wethers (28 kg and 33 kg) were supplied with ileocaecal re-entrance cannulae and received a straw pellet ration rich in crude fibre (70.5% straw, 12% chopped sugar beet, 10% cereals, 2% urea, 3% NH4HCO3 and 2.5% of a mineral mixture). In a preliminary period 50% of the digesta flow was collected on 6 successive days for 18 h each. An amount of digesta sufficient for 24 h was apportioned for hourly application and stored at a temperature of -20 degrees C for the main trial. In the main trial the two animals received intracaecally the collected digesta with a supplement of ca. 6 g hay damaged by heat/kg LW(0.75) in hourly portions over 24 h (hay made up ca. 15 and 20% resp. of the DM amount). In addition, each digesta sample was supplemented with 14C and 15N labelled urea (19.7.10(6) Bq 14C urea and 364 mg 15N excess from 15N urea). About 9% of the applied 15N amount was microbially utilized; the utilization quota was thus lower than after the application of partly hydrolyzed straw meal (16% in a previous trial). The 14C activity from 14C urea was quickly eliminated in the form of CO2 in the respiratory gases (at the 18th hour after the end of the infusion 70% excreted as CO2). The half-lives for the urea resulting from the semi-logarithmic decrease of the atom-% 15N excess in the blood plasma were 7.9 and 7.7 resp. 23% and 34% resp. of the applied 15N excess were excreted in urine. The excretion of radioactive carbon in urine, however, was at 2.8% and 4.3% resp. of the applied amount very low 120 h after the beginning of the trial (96 h after the end of the infusion). On the whole one can conclude from this trial that hay damaged by heat has only a low stimulating effect on microbial activity in the large intestine.     

Urea utilization in growing lambs. 4. N balances with unprocessed rations

N balance experiments were carried out with lambs of the ages of 8, 12 and 15 weeks fed with wheat rations with and without 2% urea supplement (N 1 and N 2) as well as with 3% urea and 20% straw (N 3) or with a soya bean meal supplement (N 4). There were no significant differences in the digestibility of the crude nutrients and in per cent of N retention between the individual ages. The straw supplement decreased the digestibility of organic matter, crude protein, crude fibre and NfE. The supplements of soya bean meal or urea increased the crude protein content in comparison to the wheat ration without supplements by 6% in the dry matter and resulted in N intakes 55 ... 60% higher and in 23 ... 38% higher N retention, which was, however, lower in relation to N intake. There were no significant differences with regard to N retention between N 2, N 3 and N 4. Consequently urea supplement to the feed mixture with 14% native crude protein resulted in increased N retention, which was not lower than with a soya bean meal supplement.     

Urea utilization in growing lambs. 6. N balance with 15N urea

Lambs of an age of 2 or 4 months and of an average live weight of 14.7 and 27.4 kg resp. received rations consisting of 44% cereals, 46% dried sugar beet pulp, 6% wheat starch, 2% urea and 2% mineral-vitamin mixture. The crude protein content was 17.1 and 15.9% resp. in the dry matter, that of native crude protein 10.6 and 9.4% resp. During a 6-day N balance period 8 and 16 g 15N urea resp. with a 15N excess (15N') of 9.26 and 9.40 atom-% were fed orally instead of commercial feeding urea. There were no significant differences between the two age groups with regard to the digestibility of the organic matter and the crude nutrients. The average N balance of 372 +/- 85 mg/kg LW 0.75/day were in the intermediate range of N retention capacity and accounted for 26 +/- 5% of the consumed N. N retention in per cent. was slightly lower in younger lambs. Projections of urea utilization in a quasi stationary state resulted in an efficiency of the utilization of 33 +/- 4%. The dismembering of the lambs at the end of the main period showed between 0.02 and 0.22 atom-% 15N' in the total N, TCA precipitable N and amino acid N of the meat. At between 0.24 and 0.38 atom-% 15N' they were highest in the heart and jaw muscles. The quota of 15N' amounts found in the total N of the meat were 10.6 +/- 3% of the 15N-intake and 20.1 +/- 5.1% of the 15N' amount remaining in the body. The bones contained 7.7 +/- 1.7% and the fleece 7.9 +/- 3.1% of the 15N'-intake. Generally seen, the total N and urea utilization was slightly lower in younger lambs than in older ones.     

The replacement of skim milk in the diet of young pigs with an extremely short suckling period. 1. Report. A comparison of skim milk, fish meal and extracted soy beans as a protein source in conjunction with whole wheat meal in a liquid feed]

40 piglets were reared in separate cages from the 13th to the 28th day of age and received a liquid milk diet (controls) or a substituted liquid diet. Half of the protein requirements of the young pigs were covered from skim milk, the other half was supplied through fish meal, extracted soya bean meal or a combination of both meals. Whole wheat meal was used as source of substitution energy. The ration containing extracted soya bean meal reduced all the digestibility coefficients with the exception of NFE. As a result, the levels of energy and nutrient intake and the rates of weight increase were lower in the experimental groups receiving the soya bean meal diet than in the control group. The same performance level as with the control diet was achieved when 50% of the skim milk in the experimental diet were replaced by wheat and fish meal.     

Utilization of 15N marked urea by the laying hen. 2. Incorporation and metabolism of 15N for the synthesis of egg protein

In an N-metabolism experiment 3 colostomized laying hybrids received 2870 mg 15N-excess (15N') per animal in 6 days in the form of urea with their conventional feed rations. During the 8-day experiment the 21 eggs laid were separated into eggshell, white of egg and yolk. Weight, N-content and 15N' were determined of the individual fractions of the eggs. On an average of the 21 eggs 4.6% of the heavy nitrogen was in the egg-shells, 50% in the white of egg and 45.5% in the yolk. 2.8%, 4.5% and 5.5% (hens 1...3) of the 15N' consumed were detected in the eggs. The maximum 15N'-output in the white of egg was reached on the 6th day, whereas 15N'-output in the yolk showed a nearly linear increase in the time of the experiment. The results show that labelled nitrogen from urea is incorporated into the egg to a lower degree than after the feeding of 15N-labelled proteins and that the development of its incorporation into the white of egg and the yolk differ from that after the feeding of 15N-labelled native proteins.     

Low phosphorus intakes by beef suckler cows in late pregnancy and early lactation

Two groups each of 10 suckler cows were given a basal diet of oat straw and pressed unmolassed sugar beet pulp for the last 19 weeks of pregnancy and the first 6 weeks of lactation. One group received 0.88 kg extracted soya bean meal (SBM) in pregnancy and 1.03 kg in lactation. The other was given 0.27 kg of a liquid supplement (LS) (containing inter alia urea and phosphoric acid) in pregnancy increasing to 0.33 kg in lactation. Both diets provided about the same amounts of digestible crude protein and about 10 g phosphorus (P) per day in pregnancy and 12 g P per day in lactation. Cows given SBM consumed marginally more straw but there were no differences in total diet digestibility. Cows given LS lost significantly more liveweight but their calves grew equally well. There were indications that cows given LS had slightly higher mean blood inorganic P and lower mean blood calcium (Ca) concentrations. Mean blood inorganic P concentrations were not below 1.4 mmol/l in pregnancy or 1.2 in lactation. There were no signs of reduction in voluntary straw intake or depraved appetite. When transferred to grass with a bull at the end of the experiment all cows were served within 24 days. It is concluded that these amounts of dietary P were adequate over the 25 weeks.     

Use of partly hydrolyzed and untreated straw meal in the feeding of breeding sows. 4. Influence on embryonic mortality and fertility

The influence of a supplement of variously treated straw materials to a ration to dry concentrate (= 1), (untreated = 2, steamed = 3, HCl-treated = 4 and partly hydrolysed = 5) during gestation on fertility and rearing performance, the embryonic survival quota of fertilized ova as well as on some selected metabolites in the blood serum was studied in 3 experiments. The integration of untreated straw meal resulted in significantly diminished performances in comparison to test groups 1 and 5 in all tested parameters of fertility and rearing performance (weight of litter). The best results were achieved in all experiments with rations of concentrate and partly hydrolysed straw meal. The individual test groups the following performance values (number of piglets born alive, weight of litter in kg) were achieved: 1 = 9.3, 12.3; 2 = 6.5, 8.2; 3 = 7.5, 9.6; 4 = 8.6, 12,4; 5 = 10.6, 14.4). Ration specific reactions could only be proved for the parameters glucose and urea out of the metabolites (insulin, glucose, cholesterol, urea tri-iodine thyronine and thyroxine).     

Effect of diet composition and feeding pattern on the prececal digestibility of starches from diverse botanical origins measured with the mobile nylon bag technique in horses

This trial was conducted to determine the extent of prececal starch digestibility depending on the botanical origin of starch and on diet characteristics (i.e., composition and feeding pattern). The prececal disappearance of six substrates (oats, barley, corn, horse bean, potato, and wheat) was measured in four cannulated horses fed (as-fed basis) 11.8 g/kg BW of a high-fiber (HF) or high-starch (HS) pelleted feed and 10.0 g/kg BW of meadow hay using the mobile bag technique (MBT). The daily feeding pattern was either three meals (two meals of pellets and one meal of hay) or five meals (three meals of pellets and two meals of hay). The experimental procedure was a 2 x 2 factorial arrangement tested in a Latin square design. After 2 wk of adaptation to the diet, collections were made on 5 d. Thirty nylon bags, composed of five bags of each substrate, were intubated to each horse during the ingestion of the morning meal. Bags were collected in the cecum, using a magnet, at 9 h postintubation. In spite of strong interindividual differences, approximately 80% of the intubated bags were collected. On average, the mean retention time of the bags was 6.2 h (+/-0.17). Regardless of the feeding pattern, the transit of the bags was faster when the fiber content of the diet was higher (P = 0.003). Likewise, regardless of the meal composition, transit was also faster when the ration was split into five daily meals (P = 0.001). The DM disappearance, corrected with particulate losses (DMD(c)), differed depending on the substrate tested (33.5, 57.1, 63.8, 67.7, 78.6, and 86.2% for potato, horse bean, oats, barley, corn, and wheat, respectively; P = 0.001). The DMD(c) of corn, barley, and potato was higher when HS was fed (P = 0.020); regardless of the substrate, DMD(c) was higher with five daily meals (P = 0.001). The starch disappearance (StarchD(c)) was different depending on the substrate (P = 0.001; 36.1, 71.2, 86.6, 89.2, 99.0, and 99.7% for potato, horse bean, barley, corn, wheat, and oats, respectively). Whatever the substrate, StarchD(c) was higher when HS was fed (P = 0.007), but it was not affected by the feeding pattern of the diet. Although passage rate was modified and feed intake was different, the botanical origin of starch was the main factor that affected prececal starch disappearance in horses.     

Estimation of the endogenous N proportions in ileal digesta and faeces in 15N-labelled pigs

Four 40 kg castrated male pigs fitted with simple 'T' cannulas in the terminal ileum were given 15N-labelled ammonium salts, added to a low protein diet, for 6 days. Excretion of 15N in urine and faeces was monitored daily throughout the labelling and subsequent experimental periods. During the experimental period the pigs were given a diet based on wheat and fish meal, supplemented with varying levels of partially hydrolysed straw meal to give crude fibre contents ranging from 40 to 132 g/kg. After adaptation to the particular levels of straw meal, faeces and ileal digesta were collected during successive 24 h periods. N digestibility values were determined by the chromic oxide ratio method. The retention of 15N labelled non-specific N was 0.46 of the dose given. The validity of using urine values as a measure of 15N abundance in endogenous N was demonstrated by the similarity of 15N abundance in urine immediately before slaughter at the end of the experiment and in the digestive secretory organs thereafter. The average amount of endogenous N passing the terminal ileum was 3.4 g/day or 0.30-0.50 of total ileal N flow. This was not affected by dietary fibre level. The proportion of faecal N which was of endogenous origin was similar to that in ileal digesta, suggesting similar utilization of endogenous and residual dietary N by hindgut bacteria. Half the endogenous N entering the large intestine was reabsorbed there. Increasing dietary crude fibre from 40 to 132 g/kg increased faecal endogenous N excretion from 1.3 to 2.0 g/animal and day.