Page 1040 - Small Animal Clinical Nutrition 5th Edition

1080 Small Animal Clinical Nutrition

VetBooks.ir Box 58-1. Medium-Chain Triglycerides.

Triacylglycerides (TAG) are the most common form of fat found in
foods and stored in body fat depots.TAG are primarily composed of kJ/g); one tablespoon (15 ml) weighs 14 g and provides 115 kcal
(481 kJ). The oil can be included in commercial foods, homemade
long-chain fatty acids (i.e., 16 to 24 carbons long). Medium-chain recipes or used to supplement commercial foods. Empiric recom-
triglycerides (MCT) are eight to 10 carbons long and are typically mendations are to provide 25 to 30% of calories as MCT.
minor constituents of a food. Increased levels of dietary MCT have MCT are also available as part of a nutritionally complete formu-
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theoretical advantages over long-chain triglycerides (LCT) for the la for human infants and children (Portagen ). This dry powder is
treatment of some forms of gastrointestinal disease. composed of corn syrup solids, MCT oil, casein, sucrose, corn oil,
The most striking difference between MCT and LCT is the former soy lecithin, vitamins and minerals. Caloric distribution is 14% pro-
are more water-soluble than the latter. MCT are normally absorbed tein, 40% fat and 46% carbohydrate. The fat content is 95% MCT.
by mechanisms independent of those used by LCT. MCT are The powder is mixed with water to produce a solution providing 1
hydrolyzed more rapidly and can rely on the small amount of intes- kcal (4.2 kJ) per ml. Alternatively, the powder can be included in a
tinal lipase available, rather than on pancreatic lipase.The products homemade food or mixed with a commercial pet food.
of hydrolysis are easily dispersed and absorbed in the absence of Potential side effects of using supplemental MCT in foods for
bile acids. Like short-chain fatty acids, medium-chain fatty acids patients with gastrointestinal disease include reduced palatability,
are absorbed at a faster rate, are not re-esterified with glycerol in vomiting and osmotic diarrhea. In cats, experimental MCT oil
enterocytes and are primarily transported from the gut via the por- administration has been linked to hepatic lipidosis. MCT products
tal vein directly to the liver. However, some MCT also appear to be are expensive and their use supplementally is generally reserved
incorporated in chylomicrons and transported to some degree in for those patients that are refractory to more traditional dietary
the thoracic duct. approaches.
MCT may have a place in the nutritional management of patients
with defects in intraluminal hydrolysis of fat (e.g., decreased pan- ENDNOTE
creatic lipase, decreased bile salts), fat malabsorption or defective a. Mead Johnson Nutritionals, Evansville, IN, USA.
lymphatic transport of fat (lymphangiectasia). MCT are prepared
commercially by hydrolysis and fractionation of coconut oil to cre- The Bibliography for Box 58-1 can be found at
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ate an oil (MCT Oil ) that contains approximately 67% caprylic acid www.markmorris.org.
(C8) and 23% capric acid (C10). The oil provides 8.3 kcal/g (34.7

1988; Remillard,1989; Sherding,1987).Higher levels of dietary Other Nutritional Factors
fiber bind digestive enzymes and bile acids, decrease pancreatic Vitamins
secretion of lipase and reduce pancreatic enzyme activity. Vitamin supplementation is rarely necessary when feeding
Insoluble fiber, through these mechanisms, decreases intralumi- commercially prepared foods. Dogs and cats usually have body
nal fat digestion and micelle formation, which selectively in- stores of vitamins A, D, E and K to last several months. How-
hibits long-chain fatty acid absorption (Remillard, 1989). ever, parenteral supplementation with fat-soluble vitamins may
Therefore, fiber may play a secondary role in reducing long- be needed if marked steatorrhea persists. Fat-soluble vitamin
chain fatty acid absorption and decreasing lymphatic flow and supplementation is warranted in cases of long-term fat malab-
subsequent lymph fluid losses. However, increased levels of fiber sorption. It is simple and cost effective to administer 1 ml of a
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(>10% DM) also reduce the caloric density and digestibility of a vitamin A, D and E solution, divided into two intramuscular
food; both factors are deemed important to the appropriate sites. This should supply fat-soluble vitamins for approximate-
management of patients with PLE. Thus, lower fiber levels ly three months. Patients with vitamin K deficiency should be
(≤5% DM), which support higher caloric density and improved treated appropriately. Vitamin K , at a dosage of 0.5 to 1
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digestibility are recommended for foods for these patients. mg/kg, subcutaneously, is recommended if a vitamin K-respon-
sive coagulopathy is suspected.
Digestibility
Feeding highly digestible (fat and digestible [soluble] carbohy- Minerals
drate ≥90% and protein ≥87%) foods provides several advan- Patients with fat malabsorption fed foods containing higher
tages for managing lymphangiectasia in dogs and cats.Nutrients levels of fat may have increased divalent cation losses (i.e., cal-
(including the energy-supplying nutrients just mentioned) in cium, magnesium, zinc and copper) because of intraluminal
highly digestible foods are more completely absorbed in the saponification. Calcium supplementation is generally not need-
proximal gut. Furthermore, highly digestible foods are associat- ed because serum calcium levels usually increase in conjunction
ed with: 1) reduced osmotic diarrhea related to fat and carbohy- with serum albumin concentrations. However, intravenous cal-
drate malabsorption, 2) reduced production of intestinal gas due cium supplementation should be instituted if hypocalcemic
to carbohydrate malabsorption and 3) decreased antigen loads tetany develops. Hypomagnesemia has been reported to occur
because smaller amounts of protein are absorbed intact. in Yorkshire terriers with lymphangiectasia (Kimmel et al,