TRUE ILEAL AVAILABILITY OF AMINO ACIDS IN CEREAL GRAINS FOR ADJUSTING PIGLETS RATIONS

The faecal and true ilealavailability (IIDs)of amino acids from wheat, barley, triticale, and maize was studied by applying a T-shaped cannula in the lower ileum. When calculating the amino acid score of cereals, it was found that the first limiting acid is ‒ lysine, the second threonine, the third ‒methionine+cystine (for wheat, barley and corn) and for triticale ‒ isoleucine and valine. The obtained estimates of the amino acids of feed components should be used in the development of complete feed for pigs.

Hydrolysis of phytate and formation of inositol phosphate isomers without or with supplemented phytases in different segments of the digestive tract of broilers

The objective was to characterise degradation ofmyo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) and formation of inositol phosphate (InsP) isomers in different segments of the broiler digestive tract. Influence of anAspergillus niger(PhyA) and twoEscherichia coli-derived (PhyE1 and PhyE2) phytases was also investigated. A total of 600 16-d-old broilers were allocated to forty floor pens (ten pens per treatment). Low-P (5·2 g/kg DM) maize–soyabean meal-based diets were fed without (basal diet; BD) or with a phytase added. On day 25, digesta from different digestive tract segments were pooled per segment on a pen-basis, freeze-dried and analysed for P, InsP isomers and the marker TiO2. InsP6degradation until the lower ileum (74 %) in BD-fed birds showed a high potential of broilers and their gut microbiota to hydrolyse InsP6in low-P diets. Different InsP patterns in different gut segments suggested the involvement of phosphatases of different origin. Supplemented phytases increased InsP6hydrolysis in the crop (P < 0·01) but not in the lower ileum. Measurements in the crop and proventriculus/gizzard confirmed publishedin vitrodegradation pathways of 3- and 6-phytases for the first time. In the intestinal segments, specifically formed InsP4–5isomers of supplemented phytases were still present, indicating further activity of these enzymes.Myo-inositol tetrakisphosphate (InsP4) accumulation differed between PhyE1 and PhyE2 compared with PhyA in the anterior segments of the gut (P < 0·01). Thus, the hydrolytic cleavage of the first phosphate group is not the only limiting step in phytate degradation in broilers.

Estimation of endogenous amino acid losses in growing chickens given soya-bean meal supplemented or not with DL-methionine

An experiment was carried out in growing chickens to study the effect of supplementation of a semi-synthetic diet containing soya-bean meal as the sole protein source with DL-methionine, to improve its biological value, on the excretion of endogenous protein and amino acids measured in lower ileum and total tract using traditional methods. Thirty-two White Rock male broilers (10 days old) were randomly divided into eight groups each of four birds, of similar body weight (mean live weight: 142·8 (s.e. 0·68) g), and individually housed in metabolism cages. Following a paired-feeding design based on metabolic body weight (kgM0·75), each group of birds was given, for an experimental period of 20 days, each of four levels of protein (60, 120, 180 or 240 g/kg; 5 days each) in two groups of isoenergetic (14·5 kJ metabolizable energy per g dry matter) and semi-synthetic diets based on soya-bean meal, either not supplemented or supplemented with 2 g/kg DL-methionine (diets S and SM, respectively). After 3 days of each treatment excreta were collected for 48 h, frozen and stored at –20ºC. At the end of the fourth treatment three chickens of each group were killed and their lower ileal contents collected. The remaining chick of each treatment was fasted for 24 h and given a protein-free diet for 8 days and excreta were collected for the last 4 days. Then (day 39 of age), chickens were killed and lower ileum contents removed and stored at –20ºC. Samples of excreta and lower ileum contents were subjected to nitrogen (N) analysis by Kjeldahl procedure and amino acid (AA) analysis by high-performance liquid chromatography. Supplementation with DL-methionine of the soya-bean meal-based diets halved total tract endogenous AA losses. Regression analysis produced a higher estimation of ileal and faecal endogenous AA excretion than feeding a protein-free diet. Endogenous AA excretion determined in the lower ileum was higher than in excreta no matter which estimation procedure was utilized. In conclusion, supplementation of dietary protein with the first limiting AA to improve its protein quality, causes an important drop in endogenous AA losses, that may have an important effect on the N economy and energy requirements in poultry. The use of regression analysis on excreta data where graded amounts of protein are given to growing chickens, seems a suitable method for determining endogenous AA losses provided that good quality proteins are used.

Gastrointestinal Tract Location of Escherichia coli O157:H7 in Ruminants

ABSTRACT Experimentally inoculated sheep and cattle were used as models of natural ruminant infection to investigate the pattern of Escherichia coli O157:H7 shedding and gastrointestinal tract (GIT) location. Eighteen forage-fed cattle were orally inoculated with E. coli O157:H7, and fecal samples were cultured for the bacteria. Three distinct patterns of shedding were observed: 1 month, 1 week, and 2 months or more. Similar patterns were confirmed among 29 forage-fed sheep and four cannulated steers. To identify the GIT location of E. coli O157:H7, sheep were sacrificed at weekly intervals postinoculation and tissue and digesta cultures were taken from the rumen, abomasum, duodenum, lower ileum, cecum, ascending colon, descending colon, and rectum. E. coli O157:H7 was most prevalent in the lower GIT digesta, specifically the cecum, colon, and feces. The bacteria were only inconsistently cultured from tissue samples and only during the first week postinoculation. These results were supported in studies of four Angus steers with cannulae inserted into both the rumen and duodenum. After the steers were inoculated, ruminal, duodenal, and fecal samples were cultured periodically over the course of the infection. The predominant location of E. coli O157:H7 persistence was the lower GIT. E. coli O157:H7 was rarely cultured from the rumen or duodenum after the first week postinoculation, and this did not predict if animals went on to shed the bacteria for 1 week or 1 month. These findings suggest the colon as the site for E. coli O157:H7 persistence and proliferation in mature ruminant animals.

The role of the ileum in the control of food intake and intestinal adaptation

Studies on animals that drastically reduce their food intake after having a jejunoileal bypass or an ileal transposition surgery suggest that the lower ileum may play a major role in the control of daily food intake. In this study, eight rats were given slow continuous infusions of either 18, 28, or 38 mL of their normal liquid diet directly into their upper ileum. They reduced their daily intake in a compensatory way for the two smaller infusions and in a more than compensatory way for the large infusion. The later result suggests that the large infusion may have caused the rats some discomfort, which led to a lower food intake. This was tested in a conditioned aversion paradigm with an ileal infusion of 26 mL of the diet into eight naive rats. These rats showed a strong aversion to the ileal infusion. Infusion of the same amount of diet into the stomach of eight other rats failed to demonstrate an aversion and showed that the procedures of the experiment did not produce the aversion. The infusion of relatively small amounts of liquid diet into the ileum produces an internal signal that reduces intake and is regulatory. A second process in which ileal infusion causes discomfort leads eventually to a more than regulatory decrease in daily intake.Key words: food intake, intestinal infusion, ileal, conditioned aversion.

Apparent amino acid absorption from feather meal by chicks

1. The apparent absorption values of individual amino acids from two samples of feather meal (FM) were determined in the lower ileum of chicks fed on diets containing magnesium ferrite as a marker.2. The average absorption values for FM amino acids were low, approximately 0.50, as compared with approximately 0.85 for soya bean, used as a control. Values for individual amino acids from FM differed distinctly, ranging from 0.20 to 0.70. Low values were obtained for aspartic acid, histidine, lysine, glutamic acid and cystine.3. An indication of the low absorption of the previously-mentioned amino acids was obtained by analysing the amino acid composition of the FM residues undigested by pepsin or pancreatin.4. The reasons for testing the apparent rather than the true absorption are discussed.

Structural and Functional Alterations in the Mucosa of Self-Filling Intestinal Blind Loops in Rats

1. Self-filling blind loops of jejunum were constructed in three groups of rats; in the first, blind loops were created without further manipulation; in the second the bile was diverted permanently into the lower ileum below the blind loop, whereas in a third neomycin was added to the drinking water throughout the experiment. Two weeks after the creation of the blind loops, they were used for structural and functional studies. 2. Morphometric and microdissection techniques demonstrated that the surface area of the individual villi of the mucosa of ‘ordinary’ blind loops had increased fourfold in comparison with corresponding control jejunum, whereas the increase was only twofold in rats with bile diversion or in the series treated with neomycin. There were proportional increases in crypt length and mitotic activity of the crypts in all three series, which suggest that the alterations in the mucosa were due to hyperplasia in both villus and crypt compartments. 3. Sucrase, succinate dehydrogenase, alkaline phosphatase and non-specific esterase activities, determined biochemically or histochemically, were reduced in the mucosae of all blind loops, though the changes were most pronounced in the ‘ordinary’ blind loops. The accumulation of l-phenylalanine by mucosal slices in vitro was depressed, although the decrease was less marked in the series treated with neomycin. 4. These results suggest that both bacteria and deconjugated bile acids play a role in the development of the hyperplastic changes of the blind-loop mucosa, but that another factor might also be involved: as a possible candidate, stasis of the intestinal contents was considered. 5. To test this hypothesis, loops of rat colon were transposed into the jejunum. Above the transposed loop, the jejunal mucosa developed hyperplasia of both villus and crypt compartments, with a reduction in its ability to accumulate l-phenylalanine. It is argued that these changes, probably caused by stasis of the intestinal contents, are triggered off by the dilatation of the gut, which may also be implicated in the mucosal alterations in blind loops.

Changes in the Distribution and Chemical Composition of Hymenolepis diminnta, and the Intestinal Nutritional Gradients of Uninfected and Parasitized Rats following a Glucose Meal

1. The protein nitrogen, carbohydrate and amino acid contents of the rat duodenum, jejunum, upper and lower ileum have been determined for up to 3 hr following the feeding of a glucose-containing test diet.2. The changes in distribution of Hymenolepis diminuta within the intestine and the changes in worm total nitrogen and carbohydrate have been followed over the same period following the same diet.3. The glucose and TCA-soluble carbohydrate contents of the uninfected gut were approximately double those of the parasitized animals.