Nutritional Care for Digestive Organs in Dogs and Cats

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Nutritional Care for Digestive Organs in Dogs and Cats

1. Wastewater Treatment Plant - The Kidneys

  • Main Functions of the Kidneys
The kidneys filter metabolic waste products such as urea and uric acid from the blood and excrete them through urine. They also reabsorb essential substances and regulate the body's water balance, pH levels, and osmotic pressure. Additionally, the kidneys secrete hormones such as erythropoietin (EPO), which promotes red blood cell production, and renin, which helps constrict blood vessels. They also regulate phosphorus and calcium levels, which are crucial for activating vitamin D.
  • Kidney Disease Classification
Kidney disease is classified into acute and chronic forms. While acute kidney disease can sometimes be cured, it often progresses to chronic kidney disease (CKD). Unlike the liver, the kidneys lack strong regenerative abilities and cannot restore lost function once damaged.
  • Importance of Early Detection
Regular health checkups are essential for early detection of kidney disease in cats. Annual comprehensive exams from the age of one are recommended. Many pet owners only conduct blood tests, overlooking urinalysis and imaging diagnostics, which are critical for early detection. In CKD's early stages, symptoms are often absent. By the time creatinine (CREA) levels rise,over 75% of kidney function may already be lost. Even with more than 25% kidney function remaining, blood tests might still appear normal, masking severe damage that could lead to kidney failure and death.

Veterinary Tip
Three key markers to monitor in pets with kidney disease are BUN (Blood Urea Nitrogen), CREA (Creatinine), and PHOS (Phosphorus). Advancements in veterinary medicine have introduced an additional marker, SDMA (Symmetric Dimethylarginine), which allows for earlier detection of kidney issues.

  • Common Causes of Kidney Disease
By the time symptoms appear, the root cause is often unclear, but possible factors include:
     1. Congenital kidney abnormalities
     2. High blood pressure
     3. Infections
     4. Immune-related diseases
     5. Acute kidney failure (caused by lilies, bacterial infections, kidney dysplasia (polycystic kidney disease), or aging)
  • Dietary Management for Chronic Kidney Disease
     1. Ensure adequate hydration to prevent dehydration.
     2. Provide sufficient energy intake—malnutrition can worsen uremia. Carbohydrates and fats are essential energy sources for kidney disease patients.
     3. Limit protein intake: Not lower than 20% DMB (Dry Matter Basis).
     4. Restrict phosphorus intake
         ◆ Stage 1, 2: 0.5-1% DMB
         ◆ Stage 3, 4: <0.5% DMB
     5. Supplement with Omega-3 fatty acids to help reduce kidney-related hypertension.
     6. Add antioxidants (Vitamin E, β-Carotene, Vitamin C) to protect kidney cells and reduce clinical symptoms.
Maintain acid-base balance using buffering agents like potassium citrate, calcium bicarbonate, and calcium carbonate to prevent metabolic acidosis, which can accelerate kidney disease progression.

2. The Silent Chemical Factory - The Liver

  • Main Functions of the Liver
The liver is one of the body's most important metabolic organs and the second-largest organ in the body. It has remarkable storage and regenerative abilities. Its primary functions include: Maintaining homeostasis by regulating metabolic processes. Transforming nutrients into usable forms for the body. Detoxifying and eliminating waste, drugs, and toxins. Producing and storing essential compounds, such as albumin (protein synthesis) and glycogen (energy storage). Participating in digestion and metabolism of food-derived nutrients.
  • Liver Disease
Liver disease occurs when a portion of liver function is compromised, leading to metabolic abnormalities. Hepatic Lipidosis (Fatty Liver) in cats is a life-threatening condition that commonly affects cats, regardless of breed, sex, or age. It is strongly associated with obesity and occurs when excess triglycerides accumulate in liver cells, leading to bile stasis and
liver dysfunction.
  • Common Causes of Liver Disease
Drug toxicity, Poisoning, Pancreatitis, Diabetes, High-fat diets, Infections, Trauma, Genetic predisposition
  • Causes of Fatty Liver Disease
Diabetes, Prolonged fasting or anorexia
  • Symptoms of Liver Disease
Dogs : Early Symptoms: Vomiting, loss of appetite Advanced Symptoms: Diarrhea, constipation, weight loss, jaundice, excessive drinking and urination, bleeding, hepatic encephalopathy, ascites
Cats : Early Symptoms: Lethargy, slow reactions Advanced Symptoms: Yellow vomit, jaundice
Fatty Liver Disease : Vomiting, diarrhea, constipation, loss of appetite, lethargy, inactivity, obesity, often associated with pancreatitis, kidney disease, tumors, and other liver diseases, jaundice
  • Dietary Management for Liver Disease
The goal of dietary management is to support liver function and reduce metabolic stress:
     1. Protein intake should be >40% ME, while carbohydrate intake should be <20% ME.
     2. Reduce liver workload: Opt for high-quality, highly digestible proteins with low ammonia production (e.g., soy, eggs) to ease detoxification.
     3. Increase water-soluble dietary fiber (e.g., lactulose) to promote bowel movements and reduce ammonia buildup in the intestines.
     4. Support liver function by supplementing branched-chain amino acids (BCAA: leucine, isoleucine, and valine).
     5. Choose energy-dense foods to provide sufficient calories, preventing muscle breakdown and excessive gluconeogenesis in the liver.
     6. Limit copper intake, as copper accumulation can damage liver cells.
     7. Supplement with Vitamin B-complex, C, A, E, K, Arginine, L-carnitine, taurine (especially for cats), and zinc.
     8. Cats with fatty liver disease often suffer from hypokalemia (low potassium) and vitamin B12 deficiency, requiring additional supplementation when necessary.

3.Dual-Function Organ - The Pancreas

  • Main Functions of the Pancreas
Although relatively small compared to other digestive organs, the pancreas plays a critical role in the body's metabolic and digestive systems. It is the only organ that has both endocrine and exocrine functions : 
Endocrine Function : The pancreas contains islets of Langerhans, which secrete insulin to regulate blood sugar levels, ensuring cells can utilize glucose as an energy source. Imbalances in insulin secretion can lead to diabetes.
Exocrine Function : The pancreas produces digestive enzymes (pancreatic juice) that are secreted into the duodenum, aiding in food breakdown and digestion.
  • Pancreatitis
Pancreatitis can be acute (reversible with treatment) or chronic (irreversible due to pancreatic atrophy or fibrosis). Diagnosing pancreatitis is particularly challenging, especially in cats, as they often show mild or no obvious symptoms. Most cases of feline pancreatitis are chronic and idiopathic (spontaneous without a clear cause). However, certain conditions—such as inflammatory bowel disease, liver disease, gallbladder disease, and diabetes—can increase the risk of pancreatitis.
  • Main Causes of Pancreatitis
Unknown causes (most cases are idiopathic), Consumption of fatty, high-salt, or high-sugar foods.
  • Contributing factors
Underlying endocrine disorders (Hyperlipidemia, hypercalcemia, diabetes), Nutritional imbalances (High-fat or low-protein diets), Obesity and excessive intake of fatty foods, Other factors: Medications, toxins, infections, pancreatic ductobstruction, trauma (e.g., abdominal surgery, accidents)
  • Symptoms of Pancreatitis
Dogs : Prayer posture (front legs stretched forward, chest lowered), vomiting, diarrhea, abdominal pain, lethargy, loss of appetite
Cats : Highly variable; generally lethargy, loss of appetite, occasional vomiting
  • Dietary Management for Pancreatitis
Managing pancreatitis through diet is complex and controversial, as different approaches exist. The primary goal is to minimize pancreatic stimulation by adjusting nutrient intake.
     1. Early nutritional support: If vomiting subsides, nutritional intervention should begin as soon as possible.
     2. Protein intake should be 30-40% DMB (dry matter basis): High-protein diets can stimulate cholecystokinin (CCK) release, which promotes pancreatic enzyme secretion and should be carefully managed.
     3. Fat intake should be adjusted based on concurrent conditions:
         ◆ Pancreatitis with kidney disease: Fat should be 20-25% DMB
         ◆ Obesity or concurrent intestinal disease: Fat should be <15% DMB
     4. Reduce fiber content to around 5% DMB.
     5. Supplement vitamin B12, as deficiencies are common in pancreatitis patients.
     6. Avoid strongly aromatic foods, as dogs and cats stimulated by the smell of protein-rich or fatty foods may experience increased pancreatic enzyme secretion.

 
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