Invited review: Use of butyrate to promote gastrointestinal tract development in calves.

Promotion of microbial butyrate production in the reticulorumen is a widely used method for enhancing forestomach development in calves. Additional acceleration of gastrointestinal tract (GIT) development, both the forestomach and lower parts of the GIT (e.g., abomasum, intestine, and also pancreas), can be obtained by dietary butyrate supplementation. For this purpose, different sources (e.g., butyrate salts or butyrins), forms (e.g., protected or unprotected), methods (e.g., in liquid feed or solid feed), and periods (e.g., before or after weaning) of butyrate administration can be used. The aim of this paper was to summarize the knowledge in the field of butyrate supplementation in feeds for newborn calves in practical situations, and to suggest directions of future studies. It has been repeatedly shown that supplementation of unprotected salts of butyrate (primarily sodium salt) in milk replacer (MR) stimulates the rumen, small intestine, and pancreas development in calves, with a supplementation level equating to 0.3% of dry matter being sufficient to exert the desired effect on both GIT development and growth performance. On the other hand, the effect of unprotected butyrins and protected forms of butyrate supplementation in MR has not been extensively investigated, and few studies have documented the effect of butyrate addition into whole milk (WM), with those available focusing mainly on the growth performance of animals. Protected butyrate supplementation at a low level (0.3% of protected product in DM) in solid feed was shown to have a potential to enhance GIT development and performance of calves fed MR during the preweaning period. Justification of this form of butyrate supplementation in solid feed when calves are fed WM or after weaning needs to be documented. After weaning, inclusion of unprotected butyrate salts in solid feed was shown to increase solid feed intake, but the effect on GIT development and function has not been determined in detail, and optimal levels of supplementation are also difficult to recommend based on available reports. Future studies should focus on comparing different sources (e.g., salts vs. esters), forms (e.g., protected vs. unprotected), and doses of supplemental butyrate in liquid feeds and solid feeds and their effect not only on the development of rumen, abomasum, and small intestine but also the omasum and large intestine. Furthermore, the most effective source, form, and dose of supplemental butyrate in solid feed depending on the liquid feed program (e.g., MR or WM), stage of rearing (e.g., pre- or postweaning), and solid composition (e.g., lack or presence of forage in the diet) need to be determined.

Effect of method of delivery of sodium butyrate on rumen development in newborn calves.

The effect of sodium butyrate (SB) supplementation in milk replacer (MR) or in starter mixture (SM) or in both MR and SM on performance, selected blood parameters, and rumen development in newborn calves was determined. Twenty-eight male calves with a mean age of 5 (±1) d were randomly allocated into 1 of 4 groups (7 animals per group) and fed (1) MR and SM, both without SB (MR(-) and SM(-), respectively); (2) MR(-) and SM supplemented with SB encapsulated within a triglyceride matrix (SM(+), 0.6% as fed; 30:70 butyrate-to-triglyceride matrix); (3) MR supplemented with crystalline SB (MR(+), 0.3% as fed) and SM(-); or (4) MR(+) and SM(+). The MR was offered in an amount equal to 10% of the initial body weight (BW) of each calf. The SM was blended with whole corn grain (50/50; wt/wt) and offered ad libitum as a starter diet (0.3% encapsulated-within-triglyceride matrix SB when SM(+) was fed) from the first day of the trial. Calves were slaughtered at d 21 of a trial (mean age 26±1 d). Addition of SB into MR (MR(+)) positively affected BW and average daily gain, tended to decrease the number of days with electrolyte therapies from d 0 to 7, and tended to positively affect fecal consistency from d 8 to 14 of the trial. Inclusion of SB into SM (SM(+)) increased starter diet intake from d 15 to 21, decreased the number of days with scours, and tended to decrease the number of days with electrolyte therapies in the whole trial period. Both MR(+) and SM(+) increased plasma glucose in the whole trial period and MR(+) increased total serum protein at d 14. The SM(+) increased plasma glucagon-like peptide-2 (GLP-2) concentration at d 7 of the trial when compared with the concentration at d 0. Both MR(+) and SM(+) increased reticulorumen weight and papillae length and width. Based on these results, it can be concluded that addition of SB in MR positively affected BW gain, health, and some metabolic intermediates of calves and it stimulated rumen development indirectly, whereas SB supplementation in SM stimulated rumen development directly. Addition of SB both in MR and SM could be recommended for rearing calves.

Dietary sodium butyrate supplementation increases digestibility and pancreatic secretion in young milk-fed calves.

The aim of this study was to test, in 8 calves fed milk formula based on soybean protein, the ability of sodium butyrate (SB) supplementation to improve nutrient digestibility and daily pancreatic secretions and to modify the kinetics of these secretions. Additionally, effects of duodenal SB infusion were evaluated. Plasma levels of gastrin, secretin, and cholecystokinin were measured. Butyrate supplementation in milk formula increased nutrient digestibility and total daily pancreatic secretions. For juice volume, this increase was most important from 12 to 17h after the morning meal. During the 3-h postprandial period, oral SB supplementation reduced the physiological decrease of postprandial pancreatic secretion (while duodenal digesta flow rate was maximal) and had a minor effect on plasma gut regulatory peptide concentrations. Compared with the diet without SB, ingestion of SB stimulated pancreatic secretion. Taken together, these results could explain the measured increase in nutrient digestibility. The data obtained after duodenal SB infusion did not indicate an effect on pancreatic secretion, apart from elevated lipase output compared with control. The mechanisms responsible for these events are not known and circulating gut regulatory peptides do not seem to be implicated. Our work brings new results regarding SB as a feed additive in young calf nutrition.

Morphology, proliferation, and ribonucleic acid and fractional protein syntheses in the small intestinal mucosa of young goats fed soy protein-based diets with or without amino acid supplementation.

The study was designed to examine whether feeding soy protein isolate as partial replacement of casein (CN) affects jejunal protein synthesis and whether effects may be ameliorated by supplementation of those AA known to be at lower concentrations in soy protein isolate than in CN. Goat kids (14 d) were fed comparable milk protein diets, in which 50% of the crude protein was CN (CAS), soy protein isolate (SPI), or soy protein isolate supplemented with AA (SPIA) for 43 d (n=8 per group). On d 42, plasma concentrations of protein, urea, and AA were measured before and after morning feeding. In the morning of d 43, [15N]RNA from yeast [13 mg/kg of body weight (BW)] was given with the diet to measure the reutilization of dietary RNA precursors for mucosal RNA biosynthesis. Four hours later, an oral dose of l-[1-(13)C]leucine (180 mg/kg of BW) was administered and blood samples were collected between -15 and +45 min relative to tracer administration for analysis of plasma 13C alpha-ketoisocaproic acid and 13C recovery in blood CO2. Kids were killed 60 min after the tracer application, and jejunal tissue was collected to determine mucosal morphology, cell proliferation, enzyme activities, RNA synthesis, and fractional protein synthesis rate. Plasma protein concentrations were higher in CAS than in SPI and SPIA. Plasma concentrations of Thr were higher in CAS than in SPI and SPIA, and those of Met were lower in SPI than in CAS and SPIA. In mid-jejunum, villus circumferences were higher in CAS than in SPI and SPIA, and villus height and villus height:crypt depth ratio were higher in CAS than in SPI. In mid-jejunum, mucosal protein concentrations were higher in CAS than in SPI and SPIA and mucosal activities of aminopeptidase N tended to be higher in CAS than in SPI, whereas activities of dipeptidyl peptidase IV tended to be lower in SPI than in SPIA. Activities of 5' nucleotidase and xanthine oxidase were lower in CAS than in SPI. The 13C recovery in blood CO2 tended to be higher in SPI than in CAS. In mid-jejunum, 15N enrichment of RNA tended to be higher in CAS than in SPI, and 13C enrichment of protein-bound Leu was higher in SPI than in CAS. In mid-jejunum, the fractional protein synthesis rate tended to be higher in SPI than in CAS. Our results revealed changes in intestinal growth after soy protein feeding that were associated with effects on intestinal RNA and protein synthesis but that were not ameliorated by AA supplementation.

Effect of sodium butyrate supplementation in milk replacer and starter diet on rumen development in calves.

Rumen development is an important factor determining early solid feed intake and performance in cattle. A popular trend towards early weaning of newborn dairy calves necessitated looking for ways of accelerating the gastrointestinal tract (GIT) development. The present study aimed to determine the effect of sodium butyrate (NaB) supplementation in milk replacer and starter diet on rumen development in rearing calves. Fourteen bull calves (5-day-old) were randomly allocated to two groups: Control (C) and NaB. The later received 0.3 % NaB in milk replacer and starter diet. Animals were in experiment up to age of 26 days. Addition of NaB to milk replacer and starter diet had no effect on daily growth rate, but reduced the weight loss observed in C calves in first 11 days of age. Additionally, the NaB calves weighed more at the end of the study and tended to have higher growth rate in the whole trial period (P<0.15). The NaB calves showed a tendency toward higher reticulorumen weight (P=0.13) and higher reticulorumen weight expressed as a percent of whole stomach weight (P=0.02) as compared to control. Histometry analysis indicated larger rumen papillae length and width (P<0.01) in NaB group, and no change in muscle layer thickness, as compared to control. Plasma glucagon-like peptide-2 relative increase was higher in NaB group than in C group, and may be involved in rumen development. In conclusion, supplementation of the diet (milk replacer and starter diet) with NaB may enhance rumen development in neonatal calves.

Control of development of gastrointestinal system in neonates.

Our recent studies of structure and function of gastrointestinal tract mucosa revealed that the domestification of Sus scrofa corresponds with the significant slowing of the organ development. On top of genetic potential, the nutritional factors (or more precisely - lack of certain biologically active substances in the feed of pregnant sows) are responsible. Moreover, feeding neonates with milk replacers instead of mother's milk further slows down the development. This is manifested by reduced mitotic activity in the crypts and enhanced apoptosis of enterocytes. The negative effects consist of slower replacement of fetal type, vacuolated enterocytes to adult type enterocytes, modified profile of brush border enzymes, alterations in intestinal mucosa barrier, higher susceptibility to infectious agents, and many others. On the other hand, farmers in order to intensify the production, shorten the suckling period imposing the neonatal piglets to be weaned at 3-4 weeks of life and even earlier. Altogether, it makes the weaning disorders one of the most important problems in pig husbandry, and the mortality of piglets in the leading pig-producing countries still reaches 10%. A number of strategies have been developed to counteract the post-weaning problems. One of them is to stimulate the development of the gastrointestinal tract of the neonate by supplementation of the sow diet with certain biologically active substances and plants. The other idea is to speed up the postnatal development of the gut mucosa for example by plant lectins. Lessons from pig studies can be also useful in human nutrition and medicine since the development of porcine gastrointestinal tract shows a great similarity to that of humans.

Preterm as compared with full-term neonatal calves are characterized by morphological and functional immaturity of the small intestine.

Intestinal diseases in neonatal calves may be due to morphological and functional immaturity. We have studied histomorphology, crypt cell proliferation rates (based on incorporation of 5-bromo-2'-deoxyuridine into DNA), presence of apoptotic cells (based on terminal deoxynucleotidyl transferase-mediated X-dUTP nick end labeling), and brush border enzyme activities in preterm calves (277 d of gestation), euthanized on d 1 (P0) or 8 (P8), and in full-term calves (290 d of gestation), euthanized on d 1 (F0) or 8 (F8). Vacuolated epithelial cells were present in ileum of P0 and F0 but not in P8 and F8. During the first 8 d, villus sizes, crypt depths, and proliferation rates of crypt cells in the small intestine of preterm calves did not significantly change. In contrast, in full-term calves during the first 8 d, villus sizes in jejunum decreased, crypt depths increased in small intestine and colon, and crypt cell proliferation increased in duodenum and jejunum. Submucosal thickness in jejunum was highest in P0, but in ileum it increased with gestational age and feeding. Gestational age x feeding interactions indicated increased activities of aminopeptidase N and reduced lactase activities only in F8 and reduced dipeptidylpeptidase IV activities only in P8. In conclusion, in preterm calves the small intestinal epithelium was immature and brush border enzyme activities differed in part from those in full-term calves.

Intestinal development in neonatal calves: effects of glucocorticoids and dependence of colostrum feeding.

The neonatal development of the gastrointestinal tract around parturition in precocious mammals is greatly affected by endocrine factors like glucocorticoids as well as by nutritional factors. We have studied the effects of glucocorticoids and colostrum supply on intestinal morphology, cell proliferation, digestive enzyme activities, and xylose absorption in neonatal calves to test the hypothesis that the intestinal development in neonatal calves is influenced by glucocorticoids, dependent on colostrum feeding. Calves designated GrFD(-) and GrFD(+) were fed a milk-based formula, whereas those designated GrCD(-) and GrCD(+) received colostrum. Dexamethasone (DEXA; 30 microg/kg/day) was injected at feeding times to calves of GrFD(+) and GrCD(+). On day 3, the D-xylose absorption was measured. The calves were euthanized on day 5 of life. Colostrum feeding increased villus sizes in jejunum and ileum, enhanced xylose absorption capacity, and increased peptidase activities in the ileum. DEXA treatment diminished sizes and cell proliferation rates of Peyer's patches in the ileum, yet increased proliferation of crypt cells in the ileum of formula-fed calves. DEXA reduced aminopeptidase N activities in the jejunum of formula-fed calves, but increased the peptidase activities mainly of colostrum-fed calves in the ileum. Thus, DEXA effects depended on intestinal segment and on different feeding, resulting in stimulation of crypt cell proliferation in the less mature ileum (of formula-fed calves) and in stimulation of peptidase activities in the more mature ileum (of colostrum-fed calves). We conclude that the effects of DEXA were related to the developmental stage of the neonatal intestine and promoted the intestinal development, depending on the developmental stage.

Feeding colostrum, its composition and feeding duration variably modify proliferation and morphology of the intestine and digestive enzyme activities of neonatal calves.

We studied the effects of amounts of colostrum consumed on intestinal morphology and proliferation and digestive enzyme activities in neonatal calves. Group GrCmax calves were fed colostrum from the first milking undiluted on d 1-3 and diluted with 25, 50, 75 and 75 parts of a milk replacer on d 4-7. Group GrC1-3 calves were fed colostrum from milkings 1-6 up to d 3 and then a milk replacer up to d 7. Group GrF1-3 calves were fed a milk-based formula (containing only traces of growth factors and hormones) up to d 3 and then a milk replacer up to d 7. Calves were killed on d 8. Differences in feeding affected villus sizes and villus height/crypt depth ratios in the duodenum (GrCmax > GrC1-3), villus areas and villus height/crypt depth ratios in the jejunum (GrC1-3 > GrF1-3) and crypt depths in the colon (GrF1-3 > GrC1-3). Furthermore, different feeding protocols affected the proliferation rates of epithelial cells in the duodenum (GrC1-3 > GrCmax; GrC1-3 > GrF1-3) and the jejunum (GrF1-3 > GrC1-3; based on Ki-67 labeling). Lipase activities in the pancreas were influenced by colostrum feeding (GrC(max) > GrC(1-3)). Colostrum intake differentially affected intestinal epithelial surface and proliferation and enzyme activities. Feeding high amounts of first colostrum seemed to enhance the survival of mature mucosal epithelial cells in selected parts of the small intestine, whereas the lack of colostrum seemed to decrease epithelial growth.

Digestion of wheat gluten and potato protein by the preruminant calf: digestibility, amino acid composition and immunoreactive proteins in ileal digesta.

Three milk substitute diets, in which the protein was either provided exclusively by skim milk powder or partially (52%) substituted by a native wheat gluten or a potato protein concentrate, were given to intact or ileo-caecal cannulated preruminant calves. The apparent faecal nitrogen digestibility was lower (P < 0.05) with the potato than with the gluten and control diets (0.90, 0.93 and 0.95, respectively). The same trend was observed at the ileal level (0.83, 0.87 and 0.91, respectively). Apparent digestibilities of most amino acids were lower with the potato than with the control diet (P < 0.05 for glutamic acid, proline, cystine, methionine, isoleucine, leucine, tyrosine and lysine). The same trend was observed with the gluten diet. Apparent digestibilities of glutamic acid and cystine were also lower (P < 0.05) with the potato than with the gluten diet. Protein fractions of Mr 43,000 and below 14,000 were detected immunochemically in ileal digesta corresponding to the potato diet, but no immunoreactivity was found in digesta with the gluten diet. However, the considerable enrichment of digesta in glutamic acid and proline with gluten indicates that dietary protein fractions rich in these 2 amino acids escaped digestion in the small intestine. With the potato diet, the undigested fractions contained high levels of aspartic acid, glutamic acid and cystine.

Digestibility, blood levels of nutrients and skin responses of calves fed soyabean and lupin proteins.

Three milk substitute diets in which the protein was provided either by skim milk only (control diet) or mainly (71%) by a commercial soyabean or lupin concentrate (soyabean or lupin diet, respectively) were given to intact or ileo-caecal-cannulated preruminant calves. In vitro tests showed that both concentrates were partially proteolysed and had low antigenic and antitryptic activities. The low antigenicity was confirmed in vivo since none of the calves produced specific plasma antibodies against dietary proteins, and skin reactions following the injection of these proteins were minor. Postprandial plasma level of triglycerides was higher with the 2 legume diets, suggesting faster abomasal emptying of fat and probably protein. Apparent faecal nitrogen digestibility was lower (P < or = 0.05) with the soyabean and lupin diets than with the control diet (0.86, 0.88 and 0.95, respectively). At the ileal level, the differences were smaller and non-significant (0.90, 0.88 and 0.92) for nitrogen, but remained significant for valine and tyrosine with the soyabean diet, and for proline, valine, methionine, leucine and lysine with the lupin diet. However, the differences were small enough to conclude that proper denaturation of soyabean and lupin proteins by processes including partial hydrolysis can suppress their antigenicity and render them very digestible.

Effects of raw pea flour on nutrient digestibility and immune responses in the preruminant calf.

Two milk substitute diets for which the protein was provided either exclusively by skim milk powder (control) or partially (34%) by dehulled raw pea flour were given for 2 and 4 wk, respectively, to five preruminant calves, each fitted with a reentrant ileocecal cannula. Ileal apparent digestibility was lower with the pea diet during wk 1 than with the control diet. Four of the cannulated calves exhibited significant intolerance to the pea diet, resulting in lower digestibility during wk 4. In contrast, fecal digestibility of the pea diet, measured in four additional calves without reentrant cannulas, did not significantly decrease between wk 1 and 4. The AA composition of ileal digesta from the first group of calves did not vary greatly, suggesting that the differences observed in their apparent digestibility of proteins were due mainly to changes in the loss of endogenous proteins. However, pea legumin survived digestion in the small intestine in amounts generally equivalent to 1 to 3% of intake. Most of that undigested fraction was smaller than the native legumin: 40 to 200 kDa instead of 360 kDa. Also, a 45-kDa fragment was detected in the urine. Increased intestinal permeability could have favored the development of the high systemic anti-pea antibody titers that were observed in all of the calves.

[Digestion of pea proteins in the abomasum and the small intestine in preruminant calves: preliminary results]. / Digestion des protéines de pois dans la caillette et l'intestin grêle du veau préruminant: résultats préliminaires.

In preruminant calves given a milk-substitute diet containing raw pea flour, the amounts of immunoreactive legumin leaving the abomasum and the ileum were found to be equivalent to about 24 and 3% of intake, respectively. This long-term presence along the digestive tract could favor its allergenic effects.

[Digestion of pea and soya proteins in the preruminant calf. I. Circulating levels of nutrients, antibody formation and intestinal permeability to macromolecules]. / Digestion des protéines de pois et do soja chez le veau préruminant. I. Taux circulants de nutriments, formation d'anticorps et perméabilité intestinale aux macromolécules.

Three milk-substitutes (control, pea and soya-bean)were given to 6 preruminant calves. In the control diet protein was almost entirely provided by skim milk powder. In the pea diet a pregelatinized dehulled pea flour provided 33.5% of the protein, the remainder being supplied by skim milk powder. In the soya-bean diet, 73.2% of the protein were provided by a soya-bean isolate and the remainder by whey powder. The concentrations of plasma triglycerides and the free alpha-amino nitrogen in the peripheral blood were lower with the pea and soya-bean diets than with the control diet before the morning meal, but became higher after feeding. That suggested a faster abomasal emptying of fat and protein with the pea and especially the soya-bean diet. Systemic antibody responses were induced against pea protein but not against soya-bean protein. No effect of the diet on the plasma concentration of immunoreactive beta-lactoglobulin was apparent after 6 days, suggesting there was no important change in gut permeability at least at that time.

[Digestion of pea and soya proteins in the preruminant calf. II. Apparent digestibility at the end of the ileum and the digestive tube]. / Digestion des protéines de pois et de soja chez le veau préruminant. II. Digestibilité apparente à la fin de l'iléon et du tube digestif.

Three milk substitutes (control, pea and soya-bean) were given to 6 preruminant calves fitted with re-entrant canulas in the terminal ileum. In the control diet, protein was almost entirely provided by skim milk powder. In the pea diet, a pregelatinized dehulled pea flour provided 33.5% of the protein, the remainder being supplied by skim milk powder. In the soya-bean powder diet 73.2% of the protein were provided by a soya-bean isolate and the remainder by whey powder. The apparent digestibility of total nitrogen was significantly lower with the pea and soya-bean diets. than with the control diet (0.92, 0.91 and 0.95 at the end of the ileum, 0.92, 0.94 and 0.97 at the end of the whole digestive tract, respectively). Also the ileal digestibility of most amino acids decreased with the pea and soya-bean diets; the differences were greatest for cystine (-0.6; non significant) with the pea diet and for threonine (-0.7; P less than 0.01) with the soya-bean diet. Irrespective of the diet the protein escaping digestion in the small intestine appeared to be mainly from endogenous and bacterial origin. Although small amounts of partially degraded dietary protein could be present in ileal digesta with the pea and soya-bean diets, their true digestibility was probably very high.