Post by angelwyche - ADMIN on Feb 29, 2008 19:06:07 GMT
Guinea Pig Essentials
The Digestive System
Guinea pigs are probably one of the smallest grass-eating mammals. They are well-developed at birth and within a short time are able to eat an adult diet. Guinea pigs are strict herbivores, and are hind-gut fermentors. Grass digestion requires a special digestive system: whereas most grass-eating mammals are quite large and have a long digestive tract, guinea pigs use a more unusual method: they practice a type of coprophagy, the eating of one's own faeces. However, they do not consume their faeces indiscriminately. They produce special soft pellets, called "cecotropes," cecotrophy may be a source of B vitamins, recycles essential gut bacteria and a means of optimizing protein utilization,
Cecotrophy may be performed 150–200 times daily. Young cavies initially populate their intestinal tract by eating the sow’s cecotrophs and pellets. Gut flora is primarily gram-positive bacteria with anaerobic actobacillus. Coliforms, yeasts, and clostridia may be present in small numbers
The mouth
The Guinea pig has 20 teeth in all, 4 incisors at the front, which can be clearly seen, and a further 16 at the back which need special equipment to observe. These teeth grow throughout life grinding away at the surface as the guinea pig eats.
From the mouth the food is moved by peristalsis in the oesophagus to the stomach.
Stomach
The stomach of a guinea pig is approximately J shaped, and lies slightly to the left. The well-developed cardiac sphincter (the valve at the top of the stomach) is lined with nonglandular stratified squamous epithelium which is what prevents vomiting. The fundus contains parietal cells that secrete acid and intrinsic factor which is essential to the absorption of Vitamin B12, further on in the ileum. as well as chief cells that secrete pepsinogen, a precursor to the enzyme pepsin involved in the break down of proteins to amino acids.. The pylorus sphincter at the bottom of the stomach allows food to move on to the duodenum
Small intestine- Duodenum, jejunum and ileum.
The bile duct enters into the duodenum and pancreatic secretions are excreted in to the food mass.
Digestion, in the stomach began with hydrochloric acid and pepsin and continues into the proximal small intestine. Amylase from the pancreas is added, although amylase is also present from saliva. The pancreas also contributes proteolytic enzymes and chymotrypsin through the accessory duct as well as most likely through small ducts connecting directly to the duodenum. Bicarbonate is secreted by the proximal duodenum to neutralize the acidity of substances leaving the stomach. The jejunum is the longest section of small bowel and appears convoluted. Proteins are absorbed in small intestine. Bacteria within the small intestine produce amylase that converts glucose to carbon dioxide and lactic acid. These products along with amino acids and vitamins are absorbed primarily in the small intestine. The bicarbonate is absorbed in the jejunum.
Fibre and Hind Gut Digestion
Guinea pigs digest much of their food in the cecum and colon (large intestine) which are at the end of the digestive tract. The cecum, a large thin-walled sac located at the junction of the small and large intestine, contains up to 65 percent of gastrointestinal contents. Within the cecum, bacteria and protozoa aid digestion of foods taken in by the guinea pig. In addition to Bacterial species, there may also be ciliated protozoa, yeasts, and small numbers of E coli and clostridia species in the gut flora. The fermentation process in the cecum results in volatile fatty acids that are absorbed across the cercal epithelium.
The colon has mucosal folds on the mesenteric side that forms a longitudinal furrow. The furrow aids in separating high protein and smaller particles from the poorer quality material that will pass out of the colon as dry fecal pellets. Antiperistalsis transports the bacteria and higher protein particles back to the cecum for further fermentation.
Fibre is needed for these bacteria and protozoa to stay in balance and function properly. Fibre also aids in maintaining normal gut motility. Without fibre the gastrointestinal tract slows down, resulting in subsequent changes in the cecum pH, fermentation, and bacterial population.
Cecotrophy, not coprophagy
Cecotrophs are formed in the colon and cecum. Fibrous material greater than 0.5 mm does not enter the cecum but transits to be formed and passed as hard fecal pellets. The smaller particles and fluid remain in the cecum or are returned to the cecum via antiperistalsis to form high nutrient particles that become coated with mucus as they pass through the colon. These are then re ingested.
This is a process that requires a high fibre diet to function properly.
Hay is essential to a pet guinea pigs diet, It plays a very important part in keeping you pets digestive tract in good order, it is important for healthy wear on their teeth. Plus guinea pigs need to chew, they enjoy it, they love playing in it
What can go wrong?
A sick guinea pig will pick up its pen mates dropping in an attempt to reset the balance in its gut
Gastrointestinal ileus
(Malfunction of the digestive tract due to gut slowdown problems) is commonly seen in guinea pigs on low fibre diets. Many times pet owners do not notice the signs associated with gastrointestinal slowdown until it is too late.
High carbohydrate diets cause several problems. Excessive glucose allows Clostridium spiroforme and E coli to colonize. This causes a drop the gut pH that inhibits normal flora and allows pathogens to proliferate and colonize. Gas and toxins can be produced by pathogenic bacteria, and motility and nutrient production and absorption are interrupted.
Other factors that may cause change to the gut environment:
Sudden change in diet.
Infection
Veterinary procedures
Pregnancy problems and delivery
Transportation
Symptoms
Decreased appetite, a bloated or tense abdomen, along with lethargy and a decrease in the volume and size of faeces passed are all signs of gastrointestinal ileus.
Treatments
If your vet has determined that there is no intestinal obstruction, there are several treatments s/he may wish to use to help your guinea pig. As always, do not perform any of these procedures or try to administer any of these medications without the supervision of a veterinarian experienced with Guinea pig disorders and treatments.
Abdominal massage one of the single most effective ways to stimulate a lazy gut into action is with gentle massage. Place the guinea pig on a secure countertop on a towel (or in your lap, if the guinea pig feels secure there), making sure he or she can't jump down and hurt themselves. With your hands and fingertips, gently massage the abdomen, but back off immediately if they express pain
Probiotic. To help re-balance the gut flora.
Simethicone (liquid, paediatric suspension or tablets) is essential for the relief of gas pain which usually accompanies ileus. For relief of acute gas pain, 1-2 cc (20mg/ml suspension) can be given as often as every hour for three doses, then 1 cc every three to eight hours. This substance has no known drug interactions, is not absorbed through the intestinal lining and acts only on a mechanical principle: it changes the surface tension of the frothy gas bubbles in the gut, joining them into larger, easier-to-pass bubbles. Simethicone is practically inert, and is safe to give, even as a precaution, as long as it is not given long term.
An intestinal motility agent, such as cisapride (Propulsid) or metoclopramide (Reglan) will help get a static intestine moving again.
Enteritis,
Intestinal inflammation associated with toxin production, is a problem commonly associated with diets that contain high levels of energy (starch and glucose). A low fibre, high starch diet promotes gut hypo motility and changes the intestinal environmental pH that allows pathogens (bad bacteria) to propagate.
The guinea pig with enteritis may have soft droppings, inactive, possibly bloated due to increased GI gas production and be hunched with the resulting abdominal pain.
This could be due to Infected, toxic or polluted food substances.
Bad bacteria will cause disease and produce toxins that can kill a guinea pig.
Some causes of Digestive Tract disease in cavies
Citrobacter
Clostridial tythlitis & dysiosis
Coccidiosis
Colbacillosis
Coranovirus
Cryptosporidiosis
Salmonella
Tyzzer’s
As some of this disease causing organisms are bacteria they can be treated with antibiotics. But care has to be taken as many antibiotics will cause diarrhoea by also killing any good gut flora in the hind gut, as well as the disease causing bacteria. It helps to give a Probiotic at a different time to the antibiotic.
‘Safe’ Antibiotics for use with guinea pigs.
These listed are less likely to cause problems.
Enrofloxacin (Baytril)
Trimethropim,
Doxycycline,
Cholamphenical.
Best to avoid
Penicillin and related antibiotics
Tetrocycline,
Amoxycillin,
Amphicillin,
Cephalexin,
Cephalosporins,
Chlortetracycline,
Erythromycin,
Penicillin,
Streptomycin
Torsion (Twisted Gut)
This can happen very quickly and is very difficult to treat.
This can cause a section of gut to loop, twist or collapse on itself. Then the gut may loose its blood supply, or it affects the guts supply of blood, causing death and necrosis to the tissues.
This can then go on to form abscesses or pockets of infection which maybe were the cause of the smelly, bloody discharge. The gut may also rupture, which causes death very quickly.
Treatment for torsion is using a painkilling relaxent such as Buscopan, to see if the muscles of the gut will relax out of the twist, Charcoal to help with gas build up, and observation using Xray or ultra sound.
But if the Gut inverts onto itself an operation is required, a very difficult operation for a guinea pig.
Angelwyche UKPCC 2008.
