The use of a partly-hydrolysed straw meal for the feeding of weaned piglets. 1. Increased production and feed expense as well as nutrient digestibility and buffer capacity in rations with various high portions of partly-hydrolysed straw meal

In studies with weaned piglets of the land race the usability of partly hydrolysed straw meal (PSM) in concentrate - straw meal mixtures was tested over a period of 56 days (42nd-98th day of life; 1st-8th week of feeding. The hydrolysed straw product was there tested in a parallel experiment each without and after neutralization (by means of CaCO3) in quotas of 5, 10 and 15% as supplement to the concentrate feed (based on dry matter) in comparison to a sole concentrate feeding. Daily weight gain and feed and energy expenditure as well as nutrient digestibility and the buffer effect of the PSM rations were ascertained. Measured by weight gain, feed intake and concentrate- and energy expenditure related weight gain, a 10% quota of partly hydrolysed straw meal in a period near weaning (1st-4th week of feeding) had the highest effect and was far superior to traditional concentrate feeding. Lower quotas of PSM in this period did not show a sufficient dietetic effect (diarrhea symptoms), higher reduced the effect on the performance parameters. In the period more remote from weaning (5th-8th week of feeding) the effect of the straw meal integration was generally reduced, a quota of about 5% proved optimal. The registered higher daily weight gains in the total test period (1st-8th week of feeding in which concentrate - straw meal mixtures (relative 106-130%) were closely related to the daily intake of digestibility organic matter. The decrease in digestibility of organic matter in the total ration remained small with the use of the well fermentable crude fibre from the hydrolysed straw product and the balance was overcompensated by higher feed intake. A pH-value decrease of the feed mixtures and a physiologically suitable influence on the pH-value in the stomachs of the test animals could be ascertained due to the buffer capacity of the hydrolysed straw products used. With regard to this, the non-buffered hydrolysed straw product had a higher effect, which was, among other things, reflected in higher performances.     

The use of partly-hydrolyzed and untreated straw meal in the feeding of breeding sows. 5. Concentration, production and absorption of volatile fatty acids in the large intestine

In 2 experiments with a total of 28 breeding sows of the country species studies were made of the fermentation, production and absorption of volatile fatty acids (VFA) in the large intestine after feeding variously treated straw materials in concentrate--straw meal mixtures. Experiment 1 ascertained that supplements of untreated (I), HCl treated (II) and partly hydrolysed straw meal (III, treatment with subsequent steaming) caused a decrease of the VFA concentration as well as considerable molar changes of the VFA in the caecal and colonal digesta in comparison of the sole feeding with concentrate (IV). The straw fibre integration increased the molar acetate quota at the expense decreased propionate and butyrate fermentation. Considering the straw meal variants this effects was least distinct after the feeding of partly hydrolysed straw meal (III). In experiment 2, which comprised the simultaneous ascertainment of VFA production in the feeding variants I and III and which was based on a representative number of animals per test group (n = 10), there were significant differences between the production quotas (I = 992; III = 1,300 mmol/animal.d) and in the absorption quotas of VFA (I = 63; II = 78%). The digestible energy from the VFA in the large intestine amounted to 711 kJ/d (I) and 1,183 kJ/d (III). The derived higher net energy gain from the hydrolysed straw product (III) was calculated at 590 kJ (40EFUpig/kg DM) and discussed together with results of feed value increase from the digestibility experiments.     

The use of partly-hydrolyzed straw meal in the feeding of weaned piglets. 3. The concentration of several parameters of protein, fat, carbohydrate and mineral metabolism in the blood serum during the use of rations with different portions of partly-hydrolyzed straw meal

Rations containing varied quotas of partly hydrolysed straw meal (PHS) were provided in mixtures of concentrate and straw meal, and selected parameters of the protein, fat, carbohydrate and mineral metabolism were registered in the blood serum at intervals (2nd and 8th week of keeping) in studies with weaned piglets of the country species. In a parallel experiment the straw hydrolysis product was provided without or after neutralization (with CaCO3) in quotas of 5, 10 and 15% in the mixed feed in comparison to the sole feeding of concentrate. Only some out of the total of 16 parameters ascertained in the blood serum showed reactions of the intermediary metabolism in the test groups caused by feeding. In general, straw crude fibre integration decreased the cholesterol level in the blood serum. Urea concentration in the blood decreased with the growing quota of PHS in the feed mixture. Deviations from the norm of various metabolites, which were mainly reflected in the period near weaning (2nd week of keeping) in an increased concentration of free glycerol and urea in the blood serum, could predominantly be registered after the sole feeding of concentrate. On the whole, there were thus certain interactions with growth performance, which clearly advocate the use of quotas of 10% of the hydrolysed straw product in the feed mixture.     

The feeding of differently treated straw materials to piglets after various weaning times. 2. Fatty acids in the large intestine and parameters of protein, fat, carbohydrate and mineral metabolism in the blood serum during the feeding of untreated, HCl-treated and partly-hydrolysed straw meal

In feeding experiments with piglets of the country species variously treated straw materials were used in concentrate--straw meal mixtures after the traditional weaning date (49th day of life) and studies were made of the fermentation of volatile fatty acids (VFA) in the large intestine (colon) and of the concentration of selected parameters of the protein, fat, carbohydrate and mineral metabolism in the blood serum of the animals. The concentrate--straw mixtures with a 10% straw quota contained untreated (II), HCl treated (HCl treatment without steaming, without (III) and with neutralization, IV) as well as partly hydrolysed straw meal (HCl treatment with subsequent steaming, without (V) and with neutralization with CaCO3, VI) were tested in comparison with sole feeding of concentrate (I) and its combination with wheat bran (VII). With regard to the fermentation processes in the large intestine in a comparison of the feeding groups (I-VII) the highest concentration and production quota of VFA was registered in I and the lowest in II. The straw treatment variants (III, IV, V and VI) took a medium position with regard to this and did not differ from each other. After their application of a significant increase in the molar acetate quota was ascertained in comparison with the sole feeding of concentrate (I), which was also characteristic of the other crude fibre sources (II and VII) and was reflected in the extension of the C2: C3 relation. Only few of the total of 15 selected parameters in the blood serum showed reactions of the intermediary metabolism of the test groups caused by feeding. The decrease of the urea concentration in the serum after the feeding of the treated straw materials (III, IV, V and VI) is particularly remarkable. In general, the urea concentration in the serum was negatively related to growth performance of the test groups. The use of HCl treated straw materials (III-VI) proved to be advantageous in comparison to the sole feeding of concentrate (I) and the use of other crude fibre sources (untreated straw meal (II) and wheat bran, VII) in the feeding regime of the keeping stage 'weaned pigs'.     

The applicable merit of untreated, HCl-treated and partly-hydrolysed straw meal in the feeding regimen of piglets after early weaning. 4. Histological findings in the digestive epithelium of the piglet

In studies with piglets of the country race the applicability of variously treated straw materials was tested in comparison with conventional concentrate feeding (I) after an early weaning date (30th-35th day of life) over an 8-week period (1st-8th week of keeping). In the rations containing 10% straw (straw-concentrate mixtures), untreated (II), HCl treated (III: HCl treatment without steaming) and partly hydrolyzed straw meal (IV: HCl treatment with subsequent steaming) were used in the feeding. Samples were taken of 4 killed animals each in the 2nd and 8th weeks of keeping for the qualitative histologic assessment of palatum durum, oesophagus and stomach, duodenum and caecum, colon ascendens, colon descendens and rectum. Although significantly lower pH values in the stomach were registered after the feeding of feed mixtures III and IV due to increased acidity (pH value decrease by 1.3 to 1.5 units) in comparison to the values in I and II, the lamina epithelialis of the palatum durum remained intact in all groups and without any signs of cauterization. Equally, considerable changes in the comparison of the feeding groups could not be detected in the structures of the oesophagus and the stomach walls or in the qualitative histologic assessment of the duodenum and the caecum. However, there were clearly distinguishable group specifics with regard to the formation of lymphoreticular tissue in the stomach and for the colon ascendens.(ABSTRACT TRUNCATED AT 250 WORDS)     

The microflora and concentrations of volatile fatty acids in the rumen of cattle fed on single component rations

The composition of the rumen microflora and the volatile fatty acids were examined in cattle free-grazing on grass or stall-fed on hay, grass pellets, oats or dried beet pulp with molasses. Total and viable counts of anaerobic bacteria were highest on the grass feeding, but viable counts as a percentage of total counts were highest when oats or beet pulp with molasses were fed. Counts of cellulolytic bacteria were lowest on these latter 2 diets, and highest on grass or grass pellet diets. Studies of the anaerobic flora showed that the composition in animals fed on grass pellets resembled more that found in animals free-grazing on grass than in those fed on hay. Counts of aerotolerant bacteria were only a small percentage of the total count, but were highest on the hay diet. On this latter diet and on grass-feeding the streptococci (identified as Streptococcus bovis) were predominant, but contrary to expectation, streptococci were found only in small numbers on the oats diet, where coryneform rods were the major type present. Although a period of 4–6 weeks was allowed for the animals to adapt to the feeds, the 2 periods of feeding on oats and dried beet pulp with molasses markedly affected the composition of the rumen flora in the subsequent periods of feeding grass pellets and hay. Ruinen volatile fatty acid analysis showed a propionogenic effect of oats and the highest percentage of butyric acid when beet pulp with molasses was fed. The expected propionogenic effect of grass pellets was not observed.     

The dynamics of the content of ammonia and volatile fatty acids in the rumen fluid during the use of dry feed rations in the cow

The development of the pH-value, the molar quota of volatile fatty acids and of the NH3 content in the change from silage rations to dried rations on the basis of pelleted feed and in dependence on the time after the beginning of feeding was tested in studies of the rumen fluid of four cows in order to explain the causes of the very low NH3 content of the rumen fluid in feeding experiments with rations based on pelleted straw-concentrate mixtures. An influence of the ration type and the time after the beginning of feeding on the molar quota of the individual volatile fatty acids and the NH3 content was ascertained. The ration type tested can cause an NH3 content in the rumen fluid below 1 mmol/l.     

Effect of different types of rations on various characteristics of ruminal and intermediary metabolism in sheep. 1. Formation of volatile fatty acids]

Studies on Ruminal Physiology were made with 15 growing female Merino sheep to investigate the influence of different types of rations on the fermentation of volatile fatty acids. The rations were constructed of green feed, straw and concentrates (type 1) or chemically treated straw pellets + concentrates (type 2). One ration (type 3) consisted of concentrates only. With regard to the total concentration of acids ration 3 was significantly superior to the 2 other types of rations. Moreover, ration 3 produced a specific fermentation pattern of the volatile fatty acids. This was characterized by a significant reduction in the molar proportion of acetate compared with ration 1 and 2 and a significant increase in the level of propionic and valeric acid relative to ration 1. Differences in the fermentation pattern between rations 1 and 2 were mainly limited to differences in the absolute and molar proportions of propionate where the straw pellet rations in each case produced the significant higher values. The acetate to propionate ratio was narrowed in the order of ration 1-3 (4.1 :1, 3.1:1, 2.6-2.9 :1). Statistically wellestablished negative correlations were found to exist between the concentrations of volatile fatty acids and the pH values which were established simultaneously.     

The effect of types of rations on a straw basis on fermentation and volatile fatty acid production in the rumen of lactating cows. 2. Ruminal fermentation and milk yield criteria after use of a high-fiber straw pellet batch as a basic ration component

Lactating Black-Pied (DSR) cows were used to study, over a period of 100 days, the influence of different basal ration types (experimental group - straw pellets; control group - dried forage + fodder root crops) on fermentation response and daily production rate of volatile fatty acids (VFA) as well as on some criteria of milk yield. Whilst only slight differences were found between the experimental groups in the molar proportions of VFA, the straw pellet-concentrate ration resulted in a lower VFA production as compared to the conventional ration. The control group's VFA production relativated to energy intake, was found to be of the same level (4.1, 4.3 and 3.9 Mol/1 kilo energetic feed equivalents/cattle) after 30, 60 and 100 days of feeding, respectively. The corresponding values in the experimental group declined from 3.3 to 2.3 and 1.9 Mol/1 kilo EF/cattle when feeding a high-fibre straw-pellet batch as basal ration component. The VFA production rates rather diverging between both groups were not found to have a uniform effect on the milk synthesis processes. Both the daily and the first 100-day milk yields did not differ between the groups but within the range of statistical error. Statistically secured positive correlations were found to exist between concentration and production of VFA which, however, depend on the basal ration type and revealed a relatively wide deviation.     

Extent and effect of fermentation in the large intestine of swine. 2. Extent of fermentation, pattern of volatile fatty acids and in vitro formation rate

After adaptation to 8 extremely different rations 40 pigs with 108 to 125 kg LW and 6 lactating sows with 183 kg were slaughtered to obtain digesta of the hindgut. From digesta of caecum and three sections of the colon microbial metabolites and in vitro-VFA-production rates were determined. pH-values increased from 5.5 to 6.3 from caecum to the end of colon. VFA-concentrations and -production-rates decreased along the bowel to one third. Highest fermentations came from rations with 50% dried beet pulp. Daily VFA-production per animal were placed between 799 and 3,134 mmol. Concerning VFA-Mol-%, ileal influx of cellulose increased acetate, high intakes raised butyrate and valeriate. By several reasons the IMOTO-method of in vitro-measuring was censured.     

The development of microflora and production of short-chain fatty acids in the digestive tract of suckled piglets and replacer-fed piglets

The objective of this study was to obtain knowledge about the postnatal development of microflora and the production of short-chain fatty acids in 24 piglets suckled by sows and 26 piglets fed on milk replacement. On day 14 piglets which had received no colostrum had higher counts of Enterobacteriaceae (p < 0.001) and coliform bacteria (p <0.001) in the jejunum contents than piglets suckled by their mother sow. Depending on age, concentrations of both lactic and acetic acid were higher in the contents of the small intestine of piglets suckled by sows compared to milk replacer-fed piglets. Replacement of maternal milk by artificial feeding adversely affected the postnatal development of the piglets. This resulted in higher morbidity and mortality in those piglets.     

Ammonia, pH and volatile fatty acids in the bovine rumen after feeding with hay.

The effect of feeding level and interval between feedings on the fermentation pattern in the bovine rumen have been investigated in experiments with hay. The animals were completely adapted heifers fitted with rumen cannulas, and the parameters measured were ammonia, pH, volatile fatty acids (VFA) and non-glucogenic/glucogenic ratio (NGGR) in the VFA mixture.Increasing feeding levels, ranging from 2/3 to 4/3 of maintenance level, resulted in higher average concentrations of VFA and lower pH in the rumen fluid. Further the highest level of intake caused a considerable diurnal variation in the pH and the concentration of total VFA, and increased the variation in the molar composition of the VFA mixture.Three feeding intervals ranging from 8 to 16 hrs., with hay administered at maintenance level, caused no changes in the fermentation pattern.Typical variations in the concentrations of ammonia and valeric acid as related to time after feeding were demonstrated, but the concentrations of the branched-chain fatty acids in the rumen fluid were found to be quite constant.It may be concluded that a representative mean value of the parameters measured, except for ammonia and valeric acid, may be based on relatively few samples when feed intake does not exceed maintenance level, whereas sampling every hour is required at higher feeding levels.     

Influence of meal frequency on postprandial variations in the production and absorption of volatile fatty acids in the digestive tract of conscious pigs

Five Large White pigs of 62.2 +/- 1.4 kg mean body weight were fitted with permanent catheters in the portal vein and carotid artery and with an electromagnetic flow probe around the portal vein to study the absorption of volatile fatty acids (VFA) by measuring the concentration of these metabolites in hourly blood samples, and by determining the portal blood flow rate for a period of 12 h after intake of a single 800-g meal (6% crude fiber) preceded by 12 or 24 h of fasting. The portal concentration of VFA mixture always highly exceeded the arterial concentration. The arterial concentrations of propionic, butyric, valeric and isovaleric acids were nearly null, accounting for an almost complete uptake of these VFA by the liver. Acetic acid also was taken up, but to a lesser extent. Total VFA absorption during 12 h was 64% higher (P less than .05) after 12 h (1,160 +/- 100 mmol/12 h) than after 24 h of preprandial fasting (740 +/- 83 mmol/12 h). It increased after the meal (P less than .05) from 82.3 +/- 7.8 mmol/h between the first and fourth hour to 107.8 +/- 7.5 mmol/h between the fifth and tenth hour when the preprandial fasting lasted 12 h; a nonsignificant increase also was found when fasting prior to the meal lasted 24 h. The composition of the VFA mixture was not modified by the length of preprandial fasting. With this type of diet there was a large predominance of acetic acid (52%) followed by propionic and butyric acids (36 and 8.5%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

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

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

Studies on rumen fermentation with special reference to the volatile fatty acid production rate in ewes during reproduction. 2. Production rate of volatile fatty acids and rumen volume

Methods and results of the measuring of the rumen volume and the passage rate as well as the dependence of the production of volatile fatty acids on the parameters mentioned are described. The correlative relations between rumen volume on the one hand and feed passage on the other hand to the production quotas are investigated. Passage rates and rumen volumes were determined with the help of the isotope dilution method. In the course of reproduction rumen volumes of 7.81, 6.41, 8.91, 7.11 in experiment 1 and 5.41, 5.81, 9.51 and 4.71 in experiment 2 were measured in the sequence early stage of gestation, late stage of gestation, lactation and the period between pregnancies. The average total production of volatile fatty acids within 12 hours amounted to 475 mmol, 265 mmol, 313 mmol and 351 mmol in experiment 1 and 155 mmol, 175 mmol, 271 mmol and 144 mmol in experiment 2 in the same sequence. The average passage duration of the feed through the digestive tract of the ewes was 32.4 h in experiment 1 and 33.6 h in experiment 2. The relatively high feed intake of the ewes resulted in a short passage duration and could be a cause of the low production quotas of the volatile fatty acids.     

Food value of straw meal in the nutrition of pigs. 1. Digestibility of the nutrients and N-balance after feeding with partially hydrolized straw meal]

Straw Meal was mixed with concentrated HCl at a mass proportion of approximately 10 : 1. After a one-hour duration of action the mixture was diluted with water (in proporation to the added HCl volume the double amount of water) and steamed in an electric steaming caldron for one hour. The partially hydrolised final product was neutralised with calcium hydroxide (3,5 kg per 10 kg HCl). In a digestibility experiment 4 pigs were fed according to the differential method with barley (supplemented with lysine and methionine) without straw meal resp. with straw meal (717 g barley dry matter+386 g straw meal dry matter per animal and day for pigs with an average live weight of 64.3 kg). In this test 21.0% of the organic matter of partially hydrolised straw meal, 0.5% of the crude fibre and 42.3% of the N-free extractives were digestible. When the animals were fed with barley exclusively (1045 g dry matter per day and animal of an average body weight of 61,4 kg), 17,1% of the 26,0 t N per animal and day were excreted in feces. After the feeding with straw meal admixtures, 34,5% of the 20,9 g N per animal and day were excreted in feces. When the feed consisted of 1,99 kg barley, 220 g fish meal and 565 g straw meal (dry matter in each case) per animal and day for the same pigs with an average body weight of 97,1 kg a digestibility of the organic matter of the partially hydrolised straw meal of 24,6% was achieved. 24.3% of the nitrogen consumed (72.9 g) by each animal per day were excreted in feces. After slaughtering, the pH-value in the caecum sould be ascertained as 6.0 to 6.5. The conclusion of this is that partially hydrolised straw meal contains approximately 20% utilisable carbohydrates and has a positive dietic effect in the digestive tract.