Histamine receptors mediate contraction of reticular groove smooth muscle of adult goats.

The present study was conducted to evaluate the effect of histamine and to characterise its receptor subtypes in reticular groove (RG) smooth muscle of adult goats. The studies were done using floor and lip regions of RG. We used tension experiments on smooth muscle of RG isolated from adult goat for functional characterisation of H1 and H2 receptors. Western blotting and immunohistochemistry experiments were conducted for molecular characterisation of these receptors. Histamine evoked concentration-dependent contraction of isolated RG circular and longitudinal smooth muscle preparation. Pyrilamine antagonised the action of histamine. Histamine did not induce any relaxant effect on RG preparations. Additionally, cimetidine did not produce any significant effect on histamine-induced response. Non-selective histaminic receptor antagonist cyproheptadine attenuated the contraction response to histamine in the smooth muscle. Molecular characterisation and localisation of H1 and H2 receptor proteins confirmed the presence of these receptors in RG. It is most likely that histamine-induced contractile effect in RG smooth muscle of goats is mediated by H1 histaminic receptors.

Effect of increasing the proportion of dietary concentrate on gastrointestinal tract measurements and brush border enzyme activity in Holstein steers.

The aim of this study was to determine the time course for adaptation of the reticulo-rumen, omasum, abomasum, and small intestine in response to an abrupt increase in the proportion of grain in the diet. Adaptive responses include tissue and digesta mass, small intestinal length, and brush border enzyme activity in the duodenum, proximal jejunum, and ileum. Twenty-five Holstein steers (213 ± 23 kg; 5 to 7 mo of age) were blocked by body weight, and within block were randomly assigned to 1 of 5 treatments: the control diet (CTRL; 92% chopped grass hay and 8% mineral and vitamin supplement on a dry matter basis) or a moderate grain diet (MGD; 50% chopped grass hay, 42% rolled barley grain, and 8% mineral and vitamin supplement) that was fed for 3 (MGD3), 7 (MGD7), 14 (MGD14), or 21 d (MGD21). Dry matter intake was limited to 2.25% of body weight to ensure that changes in dry matter intake did not confound the results. On the last day of the dietary exposure, steers were slaughtered 2 h after feeding. Reticulo-rumen tissue mass and ruminal epithelium mass in the ventral sac of the rumen were not affected by the MGD. Wet reticulo-ruminal digesta mass decreased from CTRL to MGD7 and then increased, but reticulo-ruminal digesta dry matter mass did not differ between treatments. Omasal mass, omasal tissue mass, and omasum digesta mass decreased linearly with the number of days fed MGD, but abomasal tissue mass tended to increase linearly. Duodenal tissue mass tended to increase linearly, and ileal length increased linearly with the number of days fed MGD. Lactase activity in the proximal jejunum increased linearly and maltase activity in duodenum tended to increase linearly with days fed MGD. Aminopeptidase N activity in the proximal jejunum increased cubically with days fed MGD, and dipeptidylpeptidase IV activity in ileum tended to decrease from CTRL to MGD14 and then tended to increase. Adaptation to a diet with a greater proportion of concentrate involves changes in the mass and length of regions of the gastrointestinal tract and brush border enzyme activity. These changes take place gradually over at least 3 wk.

Defining risk for low reticuloruminal pH during the diet transition period in a commercial feedlot in western Canada.

The objective of the current study was to measure reticuloruminal pH in cattle in a commercial feedlot setting to determine the incidence and extent of low reticuloruminal pH for steers and heifers as they transition to a high-concentrate finishing diet. Reticuloruminal pH was measured in 16 "mixed breed" steers (4 steers/pen with 4 pens) and 16 "mixed breed" heifers (4 heifers/pen with 4 pens) housed in commercial feedlot pens, with 227 ± 13 and 249 ± 6 cattle/pen cohort steers and heifers, respectively, for the diet transition period. Cattle were transitioned from a diet of 53.5% forage and 46.5% concentrate to a diet of 9.5% forage and 90.5% concentrate on a DM basis using a 40-d transition with 5 dietary steps with the diets containing 41.4, 44.8, 49.8, 52.5, 55.1, and 64.0% nonfibrous carbohydrate. In addition, wheat replaced barley as the grain source during the dietary transition. Reticuloruminal pH was measured using orally administered pH measurement devices that were retrieved at slaughter. Data were analyzed using a mixed model including the fixed effects of sex, diet, and the 2-way interaction to evaluate the effect of diet and sex and with the fixed effects of sex, diet, and day relative to each dietary change along with the 2- and 3-way interactions to evaluate temporal responses as a result of diet change. A repeated measures statement was included for the effect of day. Both the mean and minimum reticuloruminal pH values decreased as the proportion of concentrate in the diet increased ( < 0.001). The area and duration that pH was <5.6 increased with greater inclusion of concentrate in the diet ( < 0.001). The number of cattle experiencing low reticuloruminal pH, defined as pH < 5.6 for >180 min, increased with increasing concentrate, and by the end of the 40-d dietary transition, 83% of the cattle had experienced at least 1 bout of low reticuloruminal pH, with most experiencing between 1 and 3 bouts/diet. These data are interpreted to suggest that cattle are at high risk for experiencing low reticuloruminal pH during the dietary transition but that the extent of low reticuloruminal pH is mild. Moreover, the data suggest that the risk for low reticuloruminal pH increases with increasing proportion of concentrate in the diet. The results also suggest that susceptibility to low reticuloruminal pH may differ between steers and heifers.

Behavior of sheep fed babassu cake (Orbygnia speciosa) as a substitution for elephant grass silage.

This study aimed to evaluate the behavior of sheep fed babassu cake as a substitution for elephant grass silage. The experiment was conducted at the Federal Rural University of Amazonia (Universidade Federal Rural da Amazônia - UFRA), Brazil, using 45 sheep housed in individual stalls, with unlimited access to feed and distributed in a completely randomized design with five treatments (0, 12.5, 25, 37.5 and 50% inclusion of babassu cake) and nine replications. All of the treatments contained a roughage-to-concentrate ratio of 40:60. No differences were observed in the time spent feeding (P > 0.05), regardless of the source of roughage used. However, there was a reduction in the time spent in rumination (P < 0.05) and an increase in time spent idling (P < 0.05) when babassu cake was included in the diet. Although there was a reduction in the time spent chewing the ruminal bolus (P < 0.05), the total daily chewing time was the same for all animals (P > 0.05). However, the sheep fed babassu cake showed higher feeding and rumination efficiency (P < 0.05). Therefore, the substitution of elephant grass silage with babassu cake can be performed at up to 50% without compromising the total time spent eating and chewing, which allows increased feeding and rumination efficiency.

Pathophysiological evaluation of subacute ruminal acidosis (SARA) by continuous ruminal pH monitoring.

Evaluation of the radio-transmission pH-measurement system for monitoring the ruminal pH and subacute ruminal acidosis (SARA) in cattle is described. This is done in order to reveal the possible application of this system for detection and pathophysiological research of SARA by continuous ruminal pH measurement. The possibility of using this system for assessment of the ruminal pH in SARA cattle, and the presence of negative correlation between the ruminal pH and ruminal temperature in heathy and SARA cattle were determined. In addition, the 16S rRNA gene pyrosequencing analysis showed that the ruminal microbial community was simpler in SARA cattle, and the bacterial numbers in SARA cattle were lower than those in healthy hay-fed cattle. Concentrate feeding might have reduced the diversity of the ruminal microbial community. Changes in the ruminal microbial community of SARA cattle might be related to the changes in ruminal pH followed by the decrease in the number of some bacteria. Continuous monitoring of the ruminal pH using the radio-transmission pH-measurement system would be applied for detection and prevention of SARA in the field and pathophysiological research of SARA, including ruminal zymology and bacteriology, which have been determined previously by sampling of the ruminal fluid and measuring of ruminal pH.

Excretion patterns of solute and different-sized particle passage markers in foregut-fermenting proboscis monkey (Nasalis larvatus) do not indicate an adaptation for rumination.

Behavioral observations and small fecal particles compared to other primates indicate that free-ranging proboscis monkeys (Nasalis larvatus) have a strategy of facultative merycism(rumination). In functional ruminants (ruminant and camelids), rumination is facilitated by a particle sorting mechanism in the forestomach that selectively retains larger particles and subjects them to repeated mastication. Using a set of a solute and three particle markers of different sizes (b2, 5 and 8mm),we displayed digesta passage kinetics and measured mean retention times (MRTs) in four captive proboscis monkeys (6­18 kg) and compared the marker excretion patterns to those in domestic cattle. In addition, we evaluated various methods of calculating and displaying passage characteristics. The mean ± SD dry matter intake was 98 ± 22 g kg−0.75 d−1, 68 ± 7% of which was browse. Accounting for sampling intervals in MRT calculation yielded results that were not affected by the sampling frequency. Displaying marker excretion patterns using fecal marker concentrations (rather than amounts) facilitated comparisons with reactor theory outputs and indicated that both proboscis and cattle digestive tracts represent a series of very few tank reactors. However, the separation of the solute and particle marker and the different-sized particle markers, evident in cattle, did not occur in proboscis monkeys, in which all markers moved together, at MRTs of approximately 40 h. The results indicate that the digestive physiology of proboscis monkeys does not show typical characteristics of ruminants, which may explain why merycism is only a facultative strategy in this species.

Anaerobic digestion of corn stovers for methane production in a novel bionic reactor.

To improve the biogas production from corn stovers, a new bionic reactor was designed and constructed. The bionic reactor simulated the rumen digestion of ruminants. The liquid was separated from corn stovers and refluxed into corn stovers again, which simulated the undigested particles separated from completely digested materials and fed back again for further degradation in ruminant stomach. Results showed that the bionic reactor was effective for anaerobic digestion of corn stovers. The liquid amount and its reflux showed an obvious positive correlation with biogas production. The highest biogas production rate was 21.6 ml/gVS-addedd, and the total cumulative biogas production was 256.5 ml/gVS-added. The methane content in biogas ranged from 52.2% to 63.3%. The degradation of corn stovers were greatly enhanced through simulating the animal digestion mechanisms in this bionic reactor.

Morfologia dos pré-estômagos e de papilas ruminais de cordeiras Santa Inês em crescimento submetidas a dois planos nutricionais / Morphology of pre-stomach and ruminal papillae of growing Santa Inês female lambs under two nutritional schemes

Para se avaliar o efeito do plano nutricional e crescimento sobre a massa dos pré-estômagos, morfologia e quantificação de papilas ruminais, trinta e seis cordeiras da raça Santa Inês foram submetidas a dois planos nutricionais (ad libitum ou restrito) sendo abatidas em diferentes pesos vivo (20, 30 ou 40 kg de peso vivo), em um delineamento inteiramente casualizado balanceado em arranjo fatorial 2x3. Feito o abate, as vísceras foram pesadas livres de seu conteúdo em seguida mediu-se o volume de repleção do rúmen e retículo. Amostras do tecido ruminal oriundas dos sacos cranial e ventral foram coletadas para posteriormente serem realizadas com auxílio de lupa estereoscópica as medidas morfométricas das papilas ruminais, altura, largura da base, área, papilas por cm² e área absortiva por cm². Os resultados obtidos foram submetidos a análise de variância e as médias resultantes por tratamento foram comparadas por meio de teste de Student Newmann Keuls. Os diferentes planos nutricionais não influenciaram a massa das vísceras rúmen, retículo e omaso (P>0,05), no entanto, observou-se crescimento dessas vísceras em função do aumento do peso ao abate. O volume dessas vísceras foi afetado pelo peso ao abate, e observou-se menores volumes para animais com alimentação ad libitum (P<0,10). O número de papilas por cm² foi reduzido com o aumento do peso ao abate, sendo que altura e área foram aumentadas quando em pesos maiores. O plano nutricional afetou apenas a área e altura das papilas ruminais oriundas do saco cranial. A área absortiva não foi afetada pelos tratamentos. Plano nutricional e diferentes pesos vivos influenciam a morfologia dos pré-estômagos de cordeiras da raça Santa Inês.

For the evaluation of nutritional schemes and change on the pre-stomach morphology and quantification of rumen papillae, 36 Santa Inês female lambs were submitted to two nutritional schemes (ad libitum or restrict) and slaughtered with different live weights (20, 30 or 40 kg) in a completely randomized factorial design 2x3. After slaughter, the viscera were weighed empty and their volume was measured. Samples of ruminal wall from the cranial and ventral sacs were collected and with a stereomicroscope photographed and analyzed regarding height, basal width, area, papillae per cm² and absorptive area per cm². The results were submitted to analyses of variance and the means were compared by Student Newman Keuls test. The different nutritional schemes did not influence the weight of rumen, reticulum or omasum (P>0.05), although, growth of the viscera was observed by increase in live weight. The viscera volume was affected by live weight, and smaller volume was observed in the animals fed ad libitum diet (P<0.10). The number of papillae per cm² was reduced by the increase in live weight. Height and area of papillae were larger in heavier animals. The nutritional scheme only affected height and area of papillae of the cranial sac. The absorptive area was not affected by the treatments. Different nutritional schemes and live weights affect the pre-stomach morphology of Santa Ines female lambs.

Avaliação das características do líquido ruminal, hemogasometria, atividade pedométrica e diagnóstico de laminite subclínica em vacas leiteiras / Evaluation of the characteristics of ruminal fluid, hemogasometry, pedometer activity and subclinical laminitis diagnosis in dairy cows

Este estudo objetivou avaliar as características do líquido ruminal, hemogasometria, atividade pedométrica e ocorrência laminite subclínica, por meio da presença de enfermidades podais secundárias, em vacas leiteiras de alta produção, provenientes de um rebanho comercial. Foram avaliadas 200 vacas holandesas, oriundas da mesma propriedade, localizada na região de Araçatuba, SP, divididas em quatro grupos, sendo estes estabelecidos a partir da produtividade diária. Inicialmente procedeu-se o exame clínico dos animais, seguido da colheita de amostras do líquido ruminal, por meio de sondagem esofágica, sendo este avaliado quanto ao pH, cor, odor, consistência, sedimentação, flutuação e prova de redução pelo azul de metileno. Também foram colhidas amostras de sangue venoso para hemogasometria, além da coleta dos dados da pedometria (número de passos) e produção de leite diária das vacas. Os dados obtidos foram tabulados e submetidos à análise de correlação. Nenhum animal avaliado apresentou alterações no pH ruminal, bem como não foram encontrados distúrbios do desequilíbrio ácido básico, pois os valores de pH sanguíneo, PCO2, TCO2, HCO3- e EB estavam dentro da normalidade, durante a análise hemogasométrica. A pedometria foi efetiva como método de triagem para as vacas acometidas de afecções podais, pois se observou a redução no número de passos devido à dor, correlacionada a menor produção leiteira. Contudo, a identificação destas afecções, somente foi possível mediante exame clínico específico dos dígitos. A ocorrência das afecções podais em 49,5% do rebanho deveu-se aos fatores de riscos presentes na propriedade, como o concreto abrasivo e instalações inadequadas, associados também a possível ocorrência de acidose ruminal subaguda, não diagnosticada pela metodologia utilizada. A correlação entre os valores do pH ruminal, pedometria e hemogasometria se mostrou eficiente para o diagnóstico precoce das afecções podais e também no estabelecimento da etiologia destas enfermidades. A laminite subclínica acometeu primariamente as vacas do rebanho, considerando a etiologia multifatorial desta afecção, ocorrência e distribuição das enfermidades podais diagnosticadas.

The objectives of this study were to evaluate the characteristics of ruminal fluid, blood gas analysis, pedometer activity and suclinical laminitis occurrence, through the presence of secondary foot diseases in high production dairy cows, from a commercial herd. 200 Holstein cows originating from the same farm, located in Araçatuba/SP, Brazil, were divided into four groups, which are established from the daily milk production. Initially clinical examination of the cows was procedure, followed by sampling of rumen fluid, by esophageal tube. Fluid was evaluated for pH, color, odor, consistency, sedimentation, flotation and methylene blue reduction test. Venous blood samples were also collected for blood gas analysis, in addition to collecting data from pedometrics (number of steps) and daily milk production. Data were tabulated and submitted to correlation analysis. No animal had reported changes in rumen pH. Non-acid base imbalance were found, since the values of blood pH, PCO2, TCO2, HCO3- and BE were normal during hemogasimetric analysis. The pedometric was effective as a screening method to cows with foot diseases. It demonstrated reduction in the number of steps due to pain, correlated with lower milk production. However, the identification of foot lesions was only possible through specific digital clinical examination. The occurrence of 49.5 % of herd foot problems was due to the risk factors present in the farm. The abrasive concrete and inadequate facilities, also associated with the possible occurrence of sub-acute ruminal acidosis, were observed as risk factors. However, sub-acute ruminal acidosis was undiagnosed by the methods used. The correlation between the values of ruminal pH, and blood gas analysis pedometrics showed efficient for the early diagnosis of foot diseases and also in establishing the etiology of these diseases. Subclinical laminitis occurred primarily in cow's herd, considering the multifactorial etiology of this disease, occurrence and distribution of foot diseases diagnosed.

Effects of the feeding sequence of concentrate and forage and the feeding ratio of sake cake to grass hay on the characteristics and the entrapment effect of the ruminal mat in non-lactating dairy cows.

The effects of the feeding sequence of concentrate and forage, and of the feeding ratio of sake cake (SC) to grass hay (GH) on the ruminal mat characteristics and the entrapment effect for steamed flaked corn (SFC) by the mat were evaluated. Three non-lactating, rumen-cannulated Holstein cows were offered SC and GH using a ratio of 35:65 (SC35) or 65:35 (SC65). For SC35, SFC was fed at 1 h after or immediately before offering SC and GH, while for SC65, SFC was only fed at 1 h after. To estimate the degree of SFC entrapment in the ruminal mat, the location of SFC in the rumen and two types of mean retention time (MRT) were measured, that is, MRT for the SFC marker placed directly on the mat or taken orally. The ruminal mat was formed even when SC65 diet was consumed. The entrapment effect was not affected by the feeding sequence or the ratio. However, a more interesting finding is that the entrapment effect of the ruminal mat may not be as absolute as previously considered because of the large amount of SFC particles which precipitated at the bottom of the rumen 1 h after feeding.

Sulfated gastrin stimulates ghrelin and growth hormone release but inhibits insulin secretion in cattle.

This study was designed to determine the effects of gastrin on the circulating levels of ghrelin, growth hormone (GH), insulin, glucagon and glucose in ruminants. Two experiments were done in eight Holstein steers. Animals were randomly assigned to receive intravenous bolus injections: (1) 0.1% bovine serum albumin in saline as vehicle, 0.8, 4.0 and 20.0 µg/kg body weight (BW) of bovine sulfated gastrin-34; (2) vehicle, 0.53 µg/kg BW of bovine sulfated gastrin-17 alone or combined with 20.0 µg/kg BW of [D-Lys(3)]-GHRP-6, the selective antagonist of GHS-R1a. Blood samples were collected from -10 to 150 min relative to injection time. Concentrations of acyl and total ghrelin in response to gastrin-34 injection were significantly increased in a dose-dependent manner. Concentrations of GH were also markedly elevated by gastrin-34 injection; however, the effect of 20.0 µg/kg was weaker than that of 4.0 µg/kg. The three doses of gastrin-34 equally decreased insulin levels within 15 min and maintained the level until the time of last sampling. Gastrin-34 had no effect (P > 0.05) on the levels of glucagon and glucose. Levels of acyl ghrelin increased after administration of gastrin-17 alone or combined with [D-Lys(3)]-GHRP-6; however, [D-Lys(3)]-GHRP-6 did not block the elevation of GH by gastrin-17. The present results indicate that sulfated gastrin stimulates both ghrelin and GH release, but the GHS-R1a may not contribute to the release of GH by gastrin. Moreover, sulfated gastrin seems to indirectly maintain the homeostasis of blood glucose through the down-regulation of insulin in ruminants.

Identification of differentially expressed proteins in ruminal epithelium in response to a concentrate-supplemented diet.

Ruminal epithelium adapts to dietary change with well-coordinated alterations in metabolism, proliferation, and permeability. To further understand the molecular events controlling diet effects, the aim of this study was to evaluate protein expression patterns of ruminal epithelium in response to various feeding regimes. Sheep were fed with a concentrate-supplemented diet for up to 6 wk. The control group received hay only. Proteome analysis with differential in gel electrophoresis technology revealed that, after 2 days, 60 proteins were significantly modulated in ruminal epithelium in a comparison between hay-fed and concentrate-fed sheep (P < 0.05). Forty proteins were upregulated and 20 proteins were downregulated in response to concentrate diet. After 6 wk of this diet, only 14 proteins were differentially expressed. Among these, 11 proteins were upregulated and 3 downregulated. To identify proteins that were modulated by dietary change, two-dimensional electrophoresis was coupled with liquid chromatography electrospray ionization mass spectrometry. The differential expression of selected proteins, such as esterase D, annexin 5, peroxiredoxin 6, carbonic anhydrase I, and actin-related protein 3, was verified by immunoblotting and/or mRNA analysis. The identified proteins were mainly associated with functions related to cellular stress, metabolism, and differentiation. These results suggest new candidate proteins that may contribute to a better understanding of the signaling pathways and mechanisms that mediate rumen epithelial adaptation to high-concentrate diet.

Dose response to cinnamaldehyde supplementation in growing beef heifers: ruminal and intestinal digestion.

The objective of this study was to determine if cinnamaldehyde (CIN) could be used to improve feed intake, digestion, and immune status in growing beef heifers fed high-concentrate diets. The experiment was designed as a 4 x 4 Latin square using 4 ruminally and duodenally cannulated beef heifers with 4 treatments: control (no CIN added), 400 mg/d of CIN (low), 800 mg/d of CIN (medium), and 1,600 mg/d of CIN (high), and four 21-d periods. Feed intake, rumen pH and fermentation characteristics, site and extent of digestion, microbial N synthesis, blood metabolites, and acute phase protein response were measured. The diets consisted of 15% barley silage, 80% dry-rolled barley grain, and 5% supplement (DM basis). Intakes (kg/d) of DM, OM, NDF, starch, and N were quadratically (P = 0.04) changed with increasing CIN supplementation. The amount of OM fermented in the rumen quadratically (P = 0.02) decreased with increasing CIN. Digestibilities (% of intake) of OM, NDF, and N in the rumen were not affected by supplementing with low and medium CIN, but they were reduced by 8% (P = 0.10), 31% (P = 0.05), and 17% (P = 0.05), respectively, with high CIN. Similarly, digestibilities of OM and NDF in the total tract also tended to be reduced by 7% (P = 0.10) and 20% (P = 0.10), respectively, with high CIN because supplementation of CIN had minimal effects on intestinal digestibility. Flows (g/d) of microbial N and other nutrients to the duodenum were not affected by CIN supplementation, even though the amount of ruminal fermented OM varied with level of CIN supplementation. Rumen pH, total VFA concentration, and molar proportions of individual VFA were not affected by CIN. Although concentrations of NEFA (P = 0.06) and triglyceride (P = 0.01) were quadratically changed with increasing CIN supplementation, blood concentrations of glucose and urea N, white blood cell counts, serum amyloid A, and lipopolysaccharide in plasma were not affected by CIN. Plasma haptoglobin numerically (P = 0.11) decreased with the medium dose of CIN fed compared with control. The results indicate that supplementation of a high-concentrate diet with a low dose of CIN resulted in small increases in nutrient availability in the rumen due to increased feed intake and greater ruminal digestion of OM. However, feed intake and ruminal digestion of feeds were adversely affected when a high dose of CIN was used.

Observations on the macroscopic anatomy of the intestinal tract and its mesenteric folds in the pampas deer (Ozotoceros bezoarticus, Linnaeus 1758).

We described the macroscopic anatomy of the intestines and their peritoneal folds of five adult pampas deer (Ozotoceros bezoarticus), a cervid species considered to ingest a high proportion of grass in its natural diet. The mean (+/-SD) body weight was 17 (+/-2) kg. The small intestine and the caecocolon measured 495 (+/-37) cm and 237 (+/-24) cm in length, respectively, with an average ratio (small intestine:caecocolon) of 1.9 (+/-0.1). The ascending colon had two and a half centripetal gyri, a central flexure and two centrifugal gyri. The spiral ansa, which was similar to an ellipse, was fixed to the whole left face of the mesenterium. Apart from the peritoneal folds described in the Nomina Anatomica Veterinaria, three additional, hitherto not described folds were found: a fold that fixed the caecum to the proximal ansa of the ascending colon, one that joined the terminal part of the proximal ansa to the last centrifugal gyrus of the spiral ansa of the ascending colon, and one that linked the ascending duodenum to the proximal ansa of the ascending colon. When compared with published data from other cervids of different feeding niches, it appears that, among cervids, the ratio of small intestine to the caecocolon length does not reflect the natural diet.

[The role of the forestomachs in the adaptation of the alimentary function in ruminants]. / Rol' predzheludkov v adaptatsii alimentarnoi funktsii u zhvachnykh zivotnykh.

Dietary character of ruminants in the north is principally different between "nonselective" (cattle, sheep) and "selective" (reindeer, moose) species. Due to the developed polyfunctioning, forestomach in ruminants, primarily rumen and reticulum, are involved in the homeostasis formation in enteral and interior mediums, nutrients deposition and recirculation. That provides efficiency in utilization of deficient in nutrients forage and body reserves of wild ruminants during the winter. The original functional organization of absorption processes and nutrients recirculation across the multilayer epithelium of forestomach also promotes realization of the two levels metabolism during the year and adaptation of wild ruminants to season dynamics of nutrition.

Forestomach motility in llamas and camels.

Major aspects of forestomach anatomy in llamas and camels are described. The pattern of forestomach motility is a succession of motoric cycles, consisting of A- and B-contraction sequences and a pause. Respective differences between llamas and camels are discussed. Observations on regulation of motility are mentioned. Occurrences and courses of rumination and eructation within the motility cycles are emphasized. Motility of the forestomach achieves a selective retention of feed particles in the forestomach; a long retention time is a prerequisite for an effective microbial digestion, especially of poor quality feed.

Comparative study of forestomach digestion in llamas and sheep.

To compare digestion in the forestomach of llamas and sheep, the animals were fed four different diets: hay alone (H), low in nitrogen; the same hay with soybean meal (HS), with barley (HB) and with both soybean meal and barley (HSB). The sheep intakes were restricted to obtain about the same intake level in the two species. On average, the digestibilities of DM, OM and NDF were significantly higher in llamas: respectively, +2.7, 3.6 and 5.3 for the four diets. Added barley impaired hay digestion in the sheep, but very little in the llamas. The llamas retained nitrogen better than the sheep owing to very low urine losses. For hay alone, the retention time of digesta in the forestomach was higher in the llamas than in the sheep. In contrast, there was no difference between species for the other diets. The pH and ammonia levels were higher in llamas. In contrast, the SCFA levels were lower. In all cases the in-situ rate of digestion was greater in llamas. The low intake of llamas generally observed in the literature does not account for their better digestion. The stability of the two first compartment pH levels and an excellent cellulolytic activity are determining factors in the better digestion efficiency of plant cell walls in the llamas. However, higher NH3 levels were observed in llamas, although the urinary N excretion was lower.

[Comparative ontogenic analysis of the epithelium of the non-glandular stomach compartments of merino sheep]. / Estudio ontogenico comparativo de la lamina epitelial de los compartimentos gastricos no glandulares en ovinos merinos.

A total of 74 embryos and fetuses were used in a comparative analysis of the epithelium of the non-glandular stomach compartments of merino sheep during development. The mechanical protection showed by the tegumentary epithelium in the superficial layers of the rumen, reticulum and omasum is supported by a buffer system of neutral mucopolysaccharides secreted by the deeper strata. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Growth curves and formulas were constructed for the epithelial layers.

The ruminant digestion model using bacteria already employed early in evolution by symbiotic molluscs.

The purification and some molecular properties of six lysozymes from the gills of different mytilids and vesicomyids are described: they belong to the previously described Invertebrate lysozyme family. The predominance of the bacterial nutrition in these organisms seems to necessitate the presence of a lysozyme as in the case of the ruminant digestion model.

[Motor, digestive and secretory processes of the forestomach and the abomasum--a short review]. / Motorik, Verdauungs- und Sekretions- prozesse der Vormägen und des Labmagens--eine kurze Ubersicht.

This short review deals with some basic aspects concerning the physiology of the ruminant forestomachs and the abomasum. Following the discussion of the motoric activities, the major aspects of microbial carbohydrate and nitrogen metabolism within the reticulorumen are treated. Thereafter, some functions of the abomasum are presented in some more detail. These include the composition of abomasal contents, the mechanisms and regulation of hypochloric acid and enzyme secretion, and the mechanisms responsible for protection of the mucosa against digestion by gastric secretions.