Pattern of motility and flow of digesta in the forestomach of the Llama (Lama guanacoe f.glama)

An Alkaline Foregut Protects Herbivores from Latex in Forage, but Increases Their Susceptibility to Bt Endotoxin

About 10% of angiosperms, an estimated 20,000 species, produce latex from ubiquitous isoprene precursors. Latex, an aqueous suspension of rubber particles and other compounds, functions as an antifeedant and herbivory deterrent. It is soluble in neutral to alkaline pH, and coagulates in acidic environments. Here, I propose that foregut-fermenting herbivores such as ruminants, kangaroos, sloths, insect larvae, and tadpoles have adapted to latex in forage with the evolution of alkaline anterior digestive chamber(s). However, they consequently become susceptible to the action of Bacillus thuringiensis (Bt) δ-endotoxin and related bioinsecticides which are activated in alkaline environments. By contrast, hindgut-fermenting herbivores, such as horses and rabbits, have acidic anterior digestive chambers, in which latex coagulates and may cause gut blockage, but in which Bt is not activated. The latex-adapted foregut herbivore vs. latex-maladapted hindgut herbivore hypothesis developed in this paper has implications for hindgut-fermenting livestock and zoo animals which may be provided with latex-containing forage that is detrimental to their gut health. Further, ruminants and herbivorous tadpoles with alkaline anterior chambers are at risk of damage by the supposedly "environmentally friendly" Bt bioinsecticide, which is widely disseminated or engineered into crops which may enter animal feed streams.

The topographic and systematic anatomy of the alpaca stomach

The gastric anatomy of the alpaca (Vicugna pacos) is adapted to the physiological process of ruminating and the degradation of plant cell wall contents to a great extent. Most alpaca husbandries consist of only few animals and with the still increasing number of alpacas worldwide the number of persons who are responsible for these animals is increasing as well. Despite this, little research has been done with regard to the clinical anatomy of the stomach of alpacas. Six animals were used for dissection. The vascular system of two alpacas was injected with latex milk to illustrate the course of the blood supply to the viscera. One stomach was used to prepare formalin-fixed preparations. The stomach consisted of three compartments (C1-C3) and showed two sacculated areas in C1 and another comb-like system in C2. The compartments were lined by a smooth mucosa. Only the deep cells of C2 were lined by a papillated mucosa. The main blood supply was provided by the coeliac artery which was divided into the hepatic artery and the left gastric artery, supplying abdominal organs like liver, spleen, pancreas, and the initial part of the duodenum. Literature research on the llama stomach showed that the alpaca stomachs that were used resembled each other to a very large degree. The specific design of the stomach together with its related functions and physiological processes confirm that the evolution of Tylopoda and Ruminantia took place in parallel and not in homology.

Physical characteristics of gastrointestinal content of llama (Lama glama)

Changes in digesta dry matter (DM) and mean digesta particle size (MPS) along the gastrointestinal tract are well known in ruminants, but not in camelids. We collected digesta from the dorsal (d) and ventral (v) first forestomach compartment (C1), the second forestomach compartment (C2), three proximal segments and the subsequent glandular part of the third compartment (C3A-D), the caecum and the faeces twelve llamas (Lama glama). DM analysis indicates the presence of digesta stratification in the C1, the presence of fluid in the C2 to facilitate the sorting function of this compartment, the fluid-absorbing function of the proximal parts of the C3, the secretion of enzymes and digestive acids in the C3D, and the water-resorbing function of the lower intestinal tract. These findings illustrate the functional resemblance between the gastrointestinal tract of camelids and cattle-like ruminants (C1 equivalent to the rumen with stratified contents, C2 to the reticulum, C3A/B/C to the omasum and C3D to the abomasum). MPS analysis revealed a progressive reduction in MPS from the C1 to the distal C3. This gradual transition is different from the clear-cut threshold in ruminants between the reticulum and the omasum and had so far only been described in dromedaries (Camelus dromedarius). These findings indicate that regardless of the convergent property of rumination and resemblance of general mechanisms involved in contents stratification and particle sorting, differences between ruminants and camelids exist that could be interpreted as a more efficient functionality of the ruminant forestomach.

Degradation parameters of amaranth, barley and quinoa in alpacas fed grass hay

This study was conducted to determine the compartment 1 (C1) characteristics of alpacas (fistulated male, 7 ± 1.5 years old, 61 ± 5 kg BW) fed grass hay (GH) supplemented with amaranth (AM), quinoa (Q) and barley (B) grains. Alpacas were provided water ad libitum while housed in metabolism crates. The GH and GH plus treatments were fed at 0700 every day. Treatment periods were for 14 days in which GH or GH plus one of the grain treatments were randomly allocated. On day 14, volatile fatty acids (VFA), pH and ammonia nitrogen (NH3 -N) were determined at 1, 3, 6, 10, 14, 18 and 24 h post-feeding. C1 degradation of each feed component was also determined with the alpacas being fed GH only and the samples incubated for 0, 2, 4, 8, 14, 24, 48 and 72 h. Dry matter (DM), neutral detergent fibre (NDF) and crude protein (CP) were determined and were divided into three categories: a = immediately soluble; b = the non-soluble but degradable; and u = non-degradable/unavailable, potential extent of degradation (PE), degradation rate (c) and effective degradation (ED). C1 passage rate was determined using acid detergent insoluble ash as a marker and was calculated to be 5.5%∙h-1. Total DM intake was highest (p < 0.05) for B and resulted in a higher (p < 0.05) CP intake. GH and AM were different in mean pH (6.81 and 6.66, respectively). B NH3 -N was greater (p < 0.05) than the other treatments. Total VFA was greatest (p < 0.05) for AM, with the greatest composition differences being a shift form acetate percentage to butyrate. DM, NDF and CP degradation was different across the treatments, where PE and ED were higher (p < 0.05) for the grain treatments. The pseudo-grains AM and Q had similar C1 degradation characteristics to B.

Energy metabolism and methane production in llamas, sheep and goats fed high- and low-quality grass-based diets

This study aimed to test whether the digestive and metabolic characteristics of pseudo ruminants provide superior ability to utilise low-quality diets compared to true ruminants. A total of 18 mature, non-pregnant, non-lactating female animals, including six llamas (Lama glama), six Danish Landrace goats and six Shropshire sheep, were used in a crossover design study. The experiment lasted for two periods of three weeks. Half of the animals were fed either high-quality grass hay (HP) or low-quality grass seed straw (LP) during each period. Animals were placed in metabolic cages during the last 5 d, and gaseous exchange was measured by open-circuit indirect calorimetry for 22 h. Metabolisable energy for maintenance (MEm) and fasting energy expenditure (FEExp) were estimated by regression approach. Dry matter (DM) intake per kg(0.75) was substantially reduced in llamas and sheep, but not in goats, on the LP compared to HP diet. Llamas had lower daily energy expenditure (324 kJ · kg(-0.75)) than sheep (416 kJ · kg(-0.75)) and goats (404 kJ · kg(-0.75)) on the LP diet. Llamas in comparison with sheep and goats had lower methane emission (0.83 vs 1.34 and 1.24 l · d(-1) · kg(-0.75), p < 0.05), lower MEm (328 vs 438 and 394 kJ · d(-1) · kg(-0.75), p < 0.05) and lower FEExp (246 vs 333 and 414 kJ · d(-1) · kg(-0.75), p < 0.05), respectively. In conclusion, llamas had lower basal metabolic rate and hence maintenance requirements for energy.

A comparison of voluntary intake and in vivo digestion in guanacos (Lama guanicoe) and sheep given fresh grass

An experiment was conducted to compare the voluntary intake and in vivo digestion for guanacos and sheep when offered perennial ryegrass at three different growth stages: vegetative growth (VG), emerging inflorescence (El) and mature inflorescence (MI). Dry-matter (DM) intake ranged from 1·19 to 2·12 kg/day for the guanacos and 0·79 to 1·52 kg/day for the sheep. When expressed on a metabolic live-weight (M0·75) basis, the intake of the guanacos (55·8, 43·1 and 44·1 g DM per kg M0·75 daily on the VG, El and MI grasses respectively) and the sheep (54·4, 45·7 and 47·4g DM per kg M0·75 daily respectively) were similar (s.e.d. = 3·70). Apparent digestibilities of all food constituents were also similar. In terms of food choice, the response of the two species to grass stem differed; the guanacos selected (El) or tolerated (MI) this fraction, while the sheep tolerated (El) or avoided (MI) it.

Diversity and abundance of the bacterial 16S rRNA gene sequences in forestomach of alpacas (Lama pacos) and sheep (Ovis aries)

Two bacterial 16S rRNA gene clone libraries were constructed from the forestomach of alpacas and sheep fed alfalfa. After the amplification using the universal 16S rRNA gene primers, equal quantities of PCR products from the same species were mixed and used to construct the two libraries. Sequence analysis showed that the 60 clones from alpacas were divided into 27 phylotypes with 25% clones affiliated with Eubacterium sp. F1. The 60 clones from sheep were divided into 21 phylotypes with 7 phylotypes affiliated with Prevotella ruminicola (40% clones). Clones closely related to Clostridium proteoclasticum, Eubacterium sp. F1, Clostridium cellobioparum, Mogibacterium neglectum, Eubacterium ventriosum, Clostridiaceae bacterium WN011, Clostridium coccoides, Clostridium orbiscindens, Eubacterium sp. F1, Cytophaga sp. Dex80-37, Treponema bryantii and Pelotomaculum sp. FP were only found in the forestomach of alpacas, and those to Anaerovorax odorimutans, Treponema zioleckii, Bifidobacterium indicum, Paludibacter propionicigenes, Paraprevotella clara, Eubacterium siraeum, Desulfotomaculum sp. CYP1, Clostridium bolteae, Clostridium termitidis and Clostridiaceae bacterium DJF_LS40 only in the rumen of sheep. Quantitative real-time PCR revealed that the forestomach of alpacas had significantly lower density of bacteria, with bacterial 16S rRNA gene copies (6.89 [Log10 (copies per gram of wet weight)]), than that of sheep (7.71, P<0.01). The two clone libraries also appeared different in Shannon index (library from alpacas 3.30 and from sheep 3.04). Our results showed that there were apparent differences in the bacterial diversity and abundance in the forestomach between alpacas and sheep.

Nutritional requirements and assessing nutritional status in camelids

It has been nearly 30 years since the first imported llamas and alpacas have been commercially raised in the United States. Nutritional requirements for these animals have not been well understood and most feeding practices were based on extrapolated and experiential information. Only recently has a National Research Council committee reviewed the available published information relative to nutrient requirements of llamas and alpacas. This article summarizes current nutrient requirement recommendations and provides some practical feeding recommendations and methods to assess nutritional status.

Chewing activities and oesophageal motility during feed intake, rumination and eructation in camels

It was the aim of this study to characterize rumination behaviour, eructation and oesophageal motility in camels to identify similarities and differences between camels and domestic ruminants. Recordings were carried out in five camels fed on a hay-based diet. On an average, the duration of rumination, feeding and resting was 8.3, 5.6 and 10.1 h per 24 h, respectively. Rumination activity peaked in the morning between 9:00 and 11:00 and in the night between 02:00 and 04:00 a.m. During rumination periods, on an average 67 boluses were regurgitated per hour. Each bolus was chewed for an average of 45 s with 68 chews per min. The pause between two rumination cycles lasted on an average 9 s. Hay intake took 61 min/kg dry matter (DM), rumination lasted 71 min/kg DM of hay consumed. The regurgitation of a bolus started with a contraction of cranial compartment 1 (C 1) during a B-sequence, followed by a deep inspiration with closed glottis. Digesta enters the oesophagus, and an antiperistaltic wave transported the bolus orally. Eructation starts with a contraction of the caudal C1 during a B-sequence when the cranial C1 is relaxed. After entering the oesophagus, a rapid antiperistaltic wave transports the gas orally. Results revealed that the parameter values obtained in the camels were remarkably similar to those in domestic ruminants despite profound morphological differences and different patterns of forestomach motility.

Third compartment ulcers in the llama

The diagnosis of third compartment ulcers in the llama and alpaca is largely one of exclusion. Clinical signs may include mild to severe colic, inappetence, decreased fecal output, bruxism, and depression. Abdominocentesis results are usually unremarkable if C3 perforation has not occurred but reflective of a generalized peritonitis if full thickness ulceration has occurred. The H-2 receptor antagonists cimetidine and ranitidine do not suppress C3 acid production for a significant period of time and are of questionable efficacy in the management of C3 ulcers.

Retention of fluid and particles in the digestive tract of the llama (Lama guanacoe f. glama)

The retention times of fluid and particles of different lengths were measured in the digestive tract of the llama. PEG was used as a fluid marker; hay particles were labelled with cerium or samarium and the samples were determined by neutron activation analysis. In compartments 1 and 2 the retention time of fluid (9.7 hr) was significantly shorter than that of particles having a length of 0.2-1.0 cm (19.2 hr) and 2.5-4.0 cm (25.0 hr). In the intestine slightly significant differences in the retention times of fluid (20.1 hr) and particles (26.2 hr) were seen. In the whole digestive tract retention times were 36.2 hr for fluid, 52.0 hr for smaller particles and 59.9 hr for larger particles.

Forestomach motility in the camel (Camelus dromedarius)

There is a cyclical pattern of motility in compartments 1 and 2 of the forestomach of the camel which can be categorized into A- and B-contractions. An average motility cycle is composed of 7 A- and 5 B-contractions and lasts 5 min, including a pause of 2.3 min. The glandular sacs within the caudal sac of compartment 1 contract 1.7 sec earlier than the caudal sac. The proximal part of the canal between compartment 2 and 3 contracts 1.2 sec prior to the distal part. Forestomach motility is stimulated by distention of the cranial sac of compartment 1 and inhibited by distention of the tubiform portion of compartment 3.