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A Seminar on Taurine Deficiency in Cats Group 10 March 3, 2014 1.

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Presentation on theme: "A Seminar on Taurine Deficiency in Cats Group 10 March 3, 2014 1."— Presentation transcript:

1 A Seminar on Taurine Deficiency in Cats Group 10 March 3,

2 Biochemistry of Taurine Figure 1. Chemical structure of taurine IUPAC name: 2-aminoethanesulfonic acid Taurine is an sulfonic acid containing an amino group, yet it is not an amino acid as it is often called one, because it lacks a carboxyl group. 2

3 BiosynthesisBiosynthesis of Taurine Biosynthesis A dietary deficiency of vitamin B6 shows a depressing effect on taurine biosynthesis. 3 Methionine Cystein Cysteine sulfunic acid Cysteic acid Hypotaurine Cysteamine Taurine Phosphopantothenate Transulfuration Vit Cysteine sulfinate decarboxylase Hypotaurine decarboxylase Cysteamine dioxygenase Cysteine dioxygenase (CDO) Cysteine sulfinic acid dehydrogenase Cysteine sulfinate decarboxylase Cysteine sulfinic acid pathway

4 Taurine Transport in the Body Taurine transport across cell membrane Na + - dependent taurine transporter Taurine release from the cell via three mechanisms - Exocytosis occurs at basal membrane - Energy-dependent transporter - Ca 2+ - dependent transport 4

5 Taurine system Visual system Immune system Renal system Cardiovascular Physiological Function of Taurine Bile acid conjugation Nervoussystem 5

6 Roles of Taurine in Nervous System Taurine acts as a neurotransmitter. - Its ability to elicit neuronal hyperpolarization. - The presence of specific taurine synthesizing enzymes (CSAD), taurine-specific receptor, and a taurine transporter system. 6 CSAD = Cysteine sulfinic acid decarboxylase

7 Taurine as a neuroprotective agent. 7

8 Roles of Taurine in Cardiovascular System Taurine acts as positive inotropes by promoting calcium-ion release from sarcoplasmic reticulum in cardiac myocytes by modulates calcium transportation during the excitation- contraction coupling. 8

9 Roles of Taurine in Cardiovascular System 9 Excitation-contraction coupling of cardiac myocyte.

10 Roles of Taurine in Visual System Taurine is found in high concentration at the retina, particularly in photoreceptor cell bodies of outer nuclear layer. Kittens are more prone to taurine depletion in photoreceptor cells compared to adult cats. 10

11 outer segment Inner segment Synaptic terminal

12 CNG channel Na + /Ca 2+ exchanger disks Ca 2+ Na + Ca 2+ Na + taurine depolarization Intracellular Ca 2+ reopening Ca 2+ Na + Outer segment

13 Roles of Taurine in Immune System 13 Myeloperoxidase Taurine can eradicate free radicals generated from specific myeloperoxidase reaction, i.e. hypochlorous acid (HOCl) and hypobromous acid (HOBr), thus it can reduce oxidative stress.

14 Roles of Taurine in Renal System Renal vascular resistance Taurine aids in renal blood flow regulation. Glomerulus Elimination of reactive oxygen species (ROS) Proximal tubule Taurine affects sodium transportation. Regulation of taurine body pool size. Medullary collecting duct Taurine acts as osmoregulator, thus it can control the cell volume. Taurine may prevent glomerulonephritis, diabetic nephopathy, chronic renal failure, and acute kidney injury (AKI) 14

15 15 Roles of Taurine in Renal System Taurine transport in renal tubular cell

16 Taurine Deficiency in Cats Why are cats more likely to develop taurine deficiency? -CSAD CSAD -Bile conjugation How does taurine deficiency affects cats health? 16

17 17 Bile acid conjugation Cholesterol 7αHydroxyCholesterol Cholic acid (primary bile acid) Chenodeoxy (primary bile acid) Glyconolic acid Taurocholic acid Taurochenodeoxycholic acid Linthocolic acid (secondary bile acid) 7αHydroxylase Taurine Glycine

18 Cardiac Function Visual System Immune System Reproductive System & Development Taurine Deficiency on Cats Health 18

19 Cardiac Function 19 Decrease Ca 2+ influx Impaired sensitivity of contractile protein to Ca 2+ Cell Apoptosis Impaired systole and diastole Feline Dilated Cardiomyopathy (DCM) Heart failure

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23 Immune system 1. Leucopenia 2. Decrease respiratory burst of neutrophils 3. Decrease phagocytic activity of phagocytes 23

24 Reproductive System & Development Taurine-deficient pregnant queen 1. More incidences of fetal death (resorption), abortion, or stillbirth. 2. Reduction of taurine concentration in feline maternal milk. Kittens born from taurine- deficient female cats 1. Low survival rate 2. Low birth weight 3. Growth retardation 4. Bone malformation 5. Impaired nervous and visual system development. 24

25 25 Kittens born from taurine-deficient female cats. a. A premature kitten with congenital hydrocephalus. b. A stillbirth kitten with anencephaly. c. Severe congenital hydrocephalus, a brain from 1-year old kitten.

26 26 Nutritional Aspects Commercial diets Recommended amount Bioavailability Ingredients Processi ng Effects on digestive physiology Processing

27 27 Taurine Requirement for Cats Growth and Reproduction Adult Maintenance NutrientMinimum Maximum Taurine (extrude,%) 0.10 Taurine (canned,%) 0.20 The Association of American Feed Control Officials (AAFCO)

28 28 How to prevent taurine deficiency in cats? Processi ng Nutritional Aspects Commercial diets Homemade meal

29 Taurine amount labelled on Hills commercial cats diets 29

30 30 Taurine amount in food (mg/kg, wet weight)

31 Case study Case study Feline Dilated Cardiomyopathy History taking Domestic male cat, 4 years old, 3.8 kg. body weight Signs of depression, poor appetite, cough, and dyspnea since 3 weeks ago. The cat has muffled cardiac sound. The owner had fed the cat with commercial dog food for 1 year and 6 months. 31

32 Examination Thoracic radiograph shows severe fluid accumulation in pleural space. Electrocardiography shows decrease in 'R' wave amplitude Echocardiography shows incress in EDV = End diastolic volume or LVIDd, ESV = End systolic volume or LVIDs and shortening fraction Hematology and Serum biochemical parameter are normal Direct opthalmoscopic is normal 32

33 Shortening fraction 33 MeasurementNormal LVIDd (cm) ± 0.19 LVISd (cm) ± 0.14 D (%) ± 5.3

34 Thank you for your attention 34


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