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December 9, 2016

為何老貓體重會減輕:解釋貓的新陳代謝


The Skinny on Senior Cats: Metabolism Explained
為何老貓體重會減輕:解釋貓的新陳代謝

Last Updated on Sunday, March 20, 2016 08:07 PM
Published on Saturday, March 19, 2016 09:21 PM
Written by Mark E. Peterson, DVM, Dip. ACVIM
 
最近更新:2016年3月20日
原文刊出日:2016年3月19日
作者:獸醫馬克.彼得森 (Mark E. Peterson, DVM, Dip, ACVIM)
 
文章出處連結:
http://feline-nutrition.org/nutrition/the-skinny-on-senior-cats-metabolism-explained
 

In this article, my mission is to review energy and protein metabolism in cats. I will attempt to explain why, unfortunately, increasing the amount of fat or carbohydrate fed to an older or hyperthyroid cat generally cannot compensate for a diet deficient in an optimal protein content. As I discussed in in my previous article, energy requirements sharply and progressively increase in older cats starting at ten to twelve years of age.¹⁻³ If daily caloric intake is not increased, progressive weight loss will result, due in large part to the loss of lean body mass, i.e., muscle mass, a phenomenon referred to as sarcopeniaof aging.⁴⁻⁷ In addition to this increased caloric intake, older cats also require higher amounts of protein to maintain protein reserves compared with younger adult cats.³ ⁸⁻¹¹ As cats age, they absorb and metabolize protein less efficiently.¹⁰ Therefore, it's extremely important to feed high-quality protein, i.e., animal source rather than grain-based, as well as an adequate quantity of protein to aging cats.
 
本文目的在於探討貓的熱量和蛋白質新陳代謝。我會試著解釋為什麼提高老貓或甲亢貓所攝取的脂肪或碳水化合物,很可惜的並無法取代優質的蛋白質。如同我在之前的文章所討論(見以下譯註連結),當貓的年紀到達十至十二歲時,身體對熱量的需求會有很明顯的增加(註1到3)。如果沒有提高每日的熱量攝取,貓的體重會因為肌肉消失而減輕,這是一種被稱之為肌肉減少症的老化現象(註4到7)。除了要提高熱量攝取以外,和年輕成貓比較起來,老貓還需要比較多的蛋白質以維持蛋白質的存量(註3以及註8到11)。隨著年紀的增加,貓吸收以及代謝蛋白質的效率會減低(註10)。因此餵貓優質的蛋白質極為重要,也就是來自動物的蛋白質,而不是穀物蛋白質,此外還要提供適量的蛋白質給老貓。
 
譯註:之前的文章 http://blog.sina.com.tw/fabulous/article.php?pbgid=3388&entryid=642036
 
Animals derive energy from the oxidation of the macronutrients carbohydrate, fat, and protein.¹² Most animals, including rats and humans, generally adapt to the diet being fed and can oxidize whatever fuel mixture is contained in their prevailing diet.¹³ ¹⁴ This enables most animals, especially omnivores, to use widely differing (vary) diet compositions to satisfy their energy requirements.
 
動物獲得熱量的方式來自於氧化主要營養素,即碳水化合物、脂肪和蛋白質(註12)。大部分的動物,包括老鼠和人類,基本上身體都能適應所獲得的食物並進化氧化,不管其中主要的熱量為何(註13和14)。因此大部分的動物,尤其是雜食動物,可以安全食用三大主要營養素組合各不相同的食物,以達到熱量需求。
 
A number of veterinarians have contacted me with concerns about the potential problems associated with feeding a high protein diet to the geriatric cat, especially in those cats with kidney disease. Basically, the questions come down to the following:
 
關於餵老貓高蛋白質食物可能造成的問題,許多獸醫向我表達關切之意,尤其是有腎臟問題的貓。基本上這些獸醫的問題歸納如下:
 
·        If animals can adapt their energy intake based on a wide variety of feeding regimens, why can't we just increase the amounts of fat and carbohydrate fed to compensate for the increasing energy requirements in our senior and hyperthyroid cats? Won't that help prevent loss of muscle mass?
 
·        Can cats as obligate carnivores adapt to the same extent?
 
  • 如果動物的身體可以適應眾多不同的三大養分組合以獲得熱量,為什麼不能提高脂肪和碳水含量,給需要較多熱量的老貓和甲亢貓呢?這麼做會無法預防肌肉流失嗎?
  • 貓是絕對肉食動物,他們的身體可以適應如此的做法嗎?
 
Overview of the Body's Energy Production - Nutritional Biochemistry 101
瞭解身體如何製造熱量-營養生化學
 
Let's start with a brief review of nutritional biochemistry and the metabolic pathways an animal uses for energy production. The initial biochemical reactions by which energy is derived from carbohydrates, fats, and proteins are different. However, all three macronutrients eventually go through a final common pathway for energy generation called the citric acid cycle- also known as the tricarboxylic acid cycle, the TCA cycle or the Krebscycle.¹² ¹⁵ Please see Figure 1.
 
我們先來簡單看一下營養生化學,以及動物用來製造熱量的代謝途徑。來自於碳水、脂肪和蛋白質的熱量,其初步生化反應各不相同。不過這三大主要營養素,最後都會進入一個相同的熱量源途徑,也就是檸檬酸循環,也稱三羧酸循環或克雷布斯循環(註12&15)。請見表一。
 
Carbohydrates: Glucose derived from dietary carbohydrates is first oxidized through the glycolysis pathways to yield pyruvate and then acetyl-CoA. The acetyl-CoA is then oxidized in the citric acid cycle.¹² ¹⁵ High-energy electrons produced in the citric acid cycle enter the electron transport chain to generate adenosine triphosphate, ATP, which transfers its energy from chemical bonds to energy-absorbing chemical reactions within the cell.
 
碳水化合物:來自食物碳水化合物的葡萄糖,經由糖解作用途徑被氧化,先產生丙酮酸,然後產生乙醯輔酶A。接著乙醯酶A在檸檬酸循環中被被氧化(註12和15)。檸檬酸循環中被製造出來的高能量電子進入電子傳遞鏈,製造出三磷酸腺苷,簡稱ATP。ATP將其能量從化學鏈轉成細胞中的熱量吸收化學反應。
 
Fats: Fatty acids from dietary fats are initially oxidized to acetyl-CoA by the beta-oxidation. pathway, which then enter the citric acid cycle and subsequently generate ATP via oxidative phosphorylation in the electron transport system.
 
脂肪:來自食物脂肪的脂肪酸一開始先藉由β-氧化途徑,被氧化成乙醯輔酶A,接著進入檸檬酸循環,然後在電子傳遞系統中,透過氧化磷酸化而製造出ATP。
 

表一:中間代謝途徑
譯註:中間代謝指的是物質代謝過程中,從開始物質A到最終產物X的中間各種反應。

Protein: Once protein synthesis is maximized, excess amino acids can be used for energy by undergoing transamination and deamination. In oxidative deamination, an amino group is removed from the amino acid and converted to ammonia.
 
蛋白質:一旦蛋白質合成被最大化,過量的氨基酸可以被用來當作熱量,藉由進行轉氨基作用和脫氨基作用。在氧化去胺的過程中,氨基酸中的氨基群被除去並轉化成氨。
 
The remaining carbon skeletonfrom these deaminated amino acids, organic ketoacids,, can be recycled to make nonessential amino acids, or they can be oxidized for energy.¹² ¹⁵ If used for energy, the catabolized amino acids enter either the glycolysis pathway or the citric acid cycle to ultimately form ATP in the electron transport system. The carbon skeletons of catabolized amino acids can also be converted to glucose or ketone bodies in the liver.
 
脫去氨基的氨基酸,即酮酸,所留下的碳骨架可以被回收製造出非必需氨基酸,或是被氧化後當作熱量(註12和15)。如果是被當作熱量,異化的(也就是分解代謝過的)氨基酸進入糖解作用途徑或是檸檬酸循酸,最後在電子傳遞系統中被形成ATP。異化氨基酸的碳骨架,也可以在肝臟中被轉成葡萄糖或酮體。
 
Ammonia is toxic to the body, so enzymes convert it to urea by addition of carbon dioxide in the urea cycle, which takes place in the liver. Urea can safely diffuse into the blood and then be excreted into the urine. Please see Figure 2.
 
氨對身體是有毒的,所以酵素把氨轉成尿素,藉由在尿素循環中增加二氧化碳,這個動作是在肝臟中進行。尿素可以被安全的擴散進入血液,然後從尿液中被排出。見表二。
 
Interconversion of nutrient molecules: In metabolism, there commonly is interconversion of nutrient molecules. Excess glucose is stored as glycogen, this is known as glycogenesis; when glycogen stores are filled, glucose and amino acids are used to synthesize lipids, this is lipogenesis. Therefore, glycogen and adipose tissue both serve as long-term forms of energy storage in the body.
 
營養分子的互相轉換:在新陳代謝中,普遍存在養分互相轉換。過量葡萄糖以糖原(肝糖)的形式被貯存起來,也就是所謂的糖質新生;當糖原存量足夠時,葡萄糖和氨基酸被用來合成脂類(脂質),也就是所謂的脂質生成。因此糖原和脂肪組織兩者都以熱量的形式長期被貯存在身體中。
 
In contrast, amino acids are not "stored" in the body, other than that found in muscle and other structural proteins. Although amino acids can be converted to either fat or glucose, the opposite does not occur - fat and carbohydrates cannot be directly converted to amino acids to be made into protein.¹² ¹⁵
 
相反的,除了肌肉中的蛋白質和其他的結構蛋白之外,氨基酸是不會「貯存」在身體中的。雖然氨基酸可以被轉成脂肪或葡萄糖,但反過來的狀況並不會發生-也就是脂肪和碳水化合物無法直接轉成氨基酸以形成蛋白質(註12&15)。
 
Protein Structure, Functions & Metabolism
蛋白質的結構、功能和新陳代謝
 
Proteins, from the Greek proteios meaning "first,” are important biological molecules that consist of strings of amino acids linked together in sequence as polypeptide chains.16 Proteins vary in shape and size, some consisting of only 20-30 amino acids and others of several thousands.¹² ¹⁵
 
蛋白質一字來自希臘文的「proteios」,意思是「第一」。蛋白質是重要的生物分子,由一連串的氨基酸連結組合而成,形成多肽鏈(註16)。蛋白質的形狀和大小各不相同,有些是有二十到三十個氨基酸組合而成,有些則是好幾千個氨基酸(註12&15)。
 
Proteins are present in every living cell. In the skin, hair, cartilage, muscles, tendons, and ligaments, proteins hold together, protect and provide structure to the body. As enzymes, hormones, antibodies and globulins, they catalyze and regulate body chemistry. In addition, protein is required for growth and tissue repair, as well as for maintaining muscle mass and tone.
 
蛋白質存在每一個活細胞之中。在皮膚、毛髮、軟骨、肌肉、筋和韌帶中,蛋白質結合在一起,保護身體,提供身體結構。酵素、激素(荷爾蒙)、抗體和球蛋白都是蛋白質,作用是催化/促成以及規律身體內的化學作用。
 

表二:蛋白質的代謝分解
 
Essential and Nonessential Amino Acids
必需和非必需氨基酸
 
More than 20 amino acids are involved in the synthesis of protein in the body. Essential amino acids are those that cannot be formed in sufficient amounts to meet the requirements for growth and maintenance and must be supplied in the diet. Nonessential amino acids are those that the body can produce in sufficient amounts from other nutrients and metabolites and thus do not need to be supplied in the diet.
 
體內合成蛋白質需要二十個以上的氨基酸。必需氨基酸指的是身體無法自行合成到足夠分量,以達到成長及維持健康所需,而必需從食物獲得的氨基酸。非必需氨基酸則指的是身體可以從其他的養分和代謝物,自行製造分量足夠的氨基酸,因此不需要從食物中獲得。
 
Even with the nonessential amino acids, however, fat and carbohydrates cannot be directly converted to amino acids to be made into protein.¹² ¹⁵ Although all mammals can synthesize ten nonessential amino acids from precursor carbon skeletons, if adequate nitrogen and energy are available, there is no direct way that amino acids can be synthesized directly from either fat or carbohydrates.
 
然而即使是非必需氨基酸,脂肪和碳水化合物都無法將其直接轉成氨基酸以製成蛋白質(註12&15)。雖然在適量的氮和熱量可取得的狀況下,所有哺乳類可以從碳骨架前體合成十種非必需氨基酸,但不管是從脂肪還是碳水化合物,氨基酸皆無法被直接合成。
 
Amino Acid Catabolism & Synthesis - Protein Turnover
氨基酸的分解代謝與合成-蛋白質更新
 
Although essential amino acids are not stored as such in the body for any significant period of time, all body proteins are continuously being broken down and resynthesized in a process known as protein turnover.¹² ¹⁵ ¹⁷ During protein turnover, some amino acids enter catabolic pathways and are permanently lost. Therefore, adequate amounts of high-quality dietary protein, containing all the essential amino acids, must be consumed each day to replace both the essential and nonessential amino acids lost to catabolism.
 
雖然必需氨基酸沒有被貯存在體內一段相當的時間,不過所有的身體蛋白質在一個名為蛋白質更新的過程中,被不斷的分解和重新合成。蛋白質更新時,有些氨基酸進入代謝途徑而且永遠的流失,所以身體每天一定要消耗適量的高品質蛋白質,也就是包含所有必需氨基酸的蛋白質,以補充因為分解代謝而流失的必需和非必需氨基酸。
 
Hypermetabolic states, such as hyperthyroidism or other illness, increase both protein turnover and nitrogen losses and therefore increase the daily protein requirements.¹⁸ ¹⁹
 
當身體處於高代謝的狀態,例如罹患甲亢或其他疾病,蛋白質更新和氮的流失會變快,因此需要提高每日蛋白質攝取量(註18&19)。
 
Protein as an Energy Source
蛋白質為熱量來源
 
Unlike fat or carbohydrate, protein cannot be stored as such in the body, other than as muscle protein itself. In animals fed diets containing more protein than is needed, the extra protein is metabolized and used for energy. See Figures 1 and 2.
 
不同於脂肪和碳水化合物,蛋白質無法被貯存在體內,除了肌肉蛋白質本身以外。如果動物吃下去的食物含有超出身體所需的蛋白質,多餘的蛋白質會在被新陳代謝後當作熱量使用。見表一和二。
 
In all species, but most importantly in cats, ingested amino acids are converted to carbohydrates via gluconeogenesis.¹² ¹⁵ ¹⁷ ²⁰⁻²² This pathway is also used under starvation conditions to generate glucose and energy from the body's own proteins, particularly those found in muscle.
 
在所有的物種中,尤其是貓,攝取的氨基酸經過糖質新生轉成碳水化合物(註12、15、17、20-22)。這個途徑也會在動物挨餓的狀況下被使用,身體自身的蛋白質製造出葡萄糖和熱量,尤其是肌肉中的蛋白質。
 
Factors That Determine How Dietary Proteins are Used
決定食物蛋白質如何被使用的因素
 
·        All or None Rule: To make a certain protein, the necessary amino acids must be present in the cell in the right amounts, or the protein will not be made. Essential amino acids that are not used to make proteins are not stored.
 
全有或全無規則:要製造某一特定蛋白質,細胞中的必需氨基酸必須有正確的數量,否則蛋白質無法被製造出來。沒有被用來製造蛋白質的必需氨基酸,不會被貯存在體內。
 
·        Adequacy of Caloric Intake:  If the diet fails to provide sufficient calories as carbohydrates and fats, proteins will not be synthesized; instead the ingested amino acids will be used as a source of energy.
 
適量的熱量攝取:如果食物沒有提供適當的熱量,因為其中的碳水和脂肪的緣故,蛋白質無法被合成;相反的,被吃下去的氨基酸會被當成熱量來源。
 
·        Nitrogen Balance:  Normally, the amount of protein synthesis is equal to the amount of protein breakdown.¹² ¹⁷ If there is more protein synthesis than breakdown, then we have a positive nitrogen balance, e.g., recovery from injury. If there is greater protein breakdown than synthesis, then there is a negative nitrogen balance, e.g, starvation, illness, hyperthyroidism.
 
氮平衡:在正常的狀況下,蛋白質合成的量等於分解的量(註12&17)。如果蛋白質的合成大於分解時,那麼我們會有一個正氮平衡,例如修復受損傷的身體。如果蛋白質的分解大於合成時,則為負氮平衡,例如挨餓、疾病、甲亢。

·        Hormonal Controls:  Anabolic hormones, e.g., insulin, growth hormone, sex hormones, stimulate the production or maintenance of proteins. Catabolic hormones, e.g, glucocorticoids, thyroid hormone, stimulate the breakdown of proteins.¹⁸ ¹⁹
 
控制激素(荷爾蒙):蛋白同化激素(荷爾蒙),例如胰島素、生長激素、性激素,刺激蛋白質的製造或維持。分解代謝激素(荷爾蒙),例如糖皮質素(腎上腺皮質激素)、甲狀腺激素,刺激蛋白質的分解(註18&19)。
 
Cats Do Not Need Carbohydrate, But Have High Protein Requirements
貓不需要碳水化合物,但是對蛋白質需求高
 
The cat, as a strict carnivore, has evolved to depend on protein as a major energy source. The natural diet of cats in the wild is based upon the consumption of small mammals, birds, and insects - the composition of this diet is high in protein and fat but low in carbohydrate.²⁰⁻²² This natural diet high in animal protein contains all of a cat's essential amino acids, which is not the case for plant-based proteins.
 
貓是嚴格的肉食動物,進化使然仰賴蛋白質為主要熱量來源。貓在野外的自然食物主要是小型哺乳動物、鳥和昆蟲-皆是高蛋白質和脂肪,但碳水含量很低的獵物(註20-22)。高蛋白質的獵物包含所有貓需要的必需氨基酸,不是植物蛋白質所能提供的。
 
Cats have no dietary requirement or need for carbohydrate but are adapted physiologically and metabolically for high protein intake.²³ In support of that, normal cats do well when fed diets containing 70 percent protein.²⁴⁻²⁷ The lack of a need for dietary carbohydrates is related to the fact that cats have developed a tremendous ability to synthesize their needed glucose from protein catabolism via hepatic gluconeogenesis.²⁴ ²⁵ ²⁸
 
貓對碳水沒有需求或需要,生理結構和代謝皆是為了適應攝取高蛋白質(註23),因此一般正常貓吃下蛋白質含量百分之七十的食物時,身體表現良好(註24到27)。貓不需要碳水化合物,因為他們早已具備極佳的能力,藉由肝臟的糖質新生(註24、25和28),將蛋白質分解,合成身體需要的葡萄糖。
 
Cats have a much higher protein requirement than other species, such as dogs and humans. The protein requirement for the adult cat is 2-3 times as much as the adult dog, and their protein requirement increases even further as cats reach old age.³ ⁸⁻¹¹²³ This high protein requirement of cats is primarily related to the fact that cats have a limited ability to decrease the hepatic enzymes responsible for amino acid catabolism, even when fed a lower than optimal protein intake.²⁴ ²⁹ ³⁰
 
和其他物種比起來,例如狗和人類,貓的蛋白質需求高出許多。成貓的蛋白質需求是成犬的二到三倍,而且隨著年紀的增加,蛋白質的需求也跟著提高(註3,8-11,23)。高蛋白質需求是因為,在降低負責分解氨基酸的肝臟酵素活動力時,貓的能力有限,即使所攝取的蛋白質低於身體所需。
 
註:貓的肝臟酵素活動力一直都是高的,以下有解釋。
 
The Domestic Cat: A Metabolically Inflexible Carnivore
家貓:代謝固定的肉食動物
 
When most omnivores, e.g., humans, rats, pigs, dogs, ingest a diet high in protein, the activities of the amino acid-catabolizing enzymes in the liver increase to cope with the higher flux of amino acids.³¹⁻³³ The activity of the urea cycle enzymes also increase to metabolize the increased ammonia generated upon the catabolism of the amino acids. On the other hand, when fed a diet low in protein, omnivores accommodate by lowering the hepatic activity of these catabolic enzymes of amino acid metabolism, as well as decreasing hepatic urea production.³¹⁻³³
 
當大部分的雜食動物,例如人類、老鼠、豬和狗,吃下高蛋白質食物時,肝臟內分解氨基酸的酵素活動力會提高,以因應比較高的氨基酸流量(註31-33)。尿素循環酵素的活動力也會提高,以代謝因為分解氨基酸而提高的氨含量。另一方面,當雜食動物吃下蛋白質比較低的食物時,肝臟內分解氨基酸的這些代謝酵素的活動力也會跟著降低,肝臟尿素的製造也會減少(註31-33)。
 
By contrast, cats have a very limited ability to down-regulate these hepatic catabolic enzymes when fed a low-protein diet. In a classic study, Rogers, et al, compared the activity of several catabolic enzymes of amino acid metabolism in adult cats fed either a high- or low-protein diet or fasted for five days.29 Results showed little changes in the hepatic enzyme activities between the three groups of cats, with hepatic enzyme activities remaining set at high levels to cope with a high protein diet, even when they weren't being fed!
 
相反的,餵貓吃低蛋白質食物時,貓在降低肝臟分解酵素的活動力這方面,能力非常有限。羅傑斯等人做了一項研究,針對三組貓研究分解氨基酸的代謝酵素活動力,這三組貓分別餵的是高蛋白食物、低蛋白食物,以及斷食五天的貓(註29)。結果顯示這三組貓之間,肝臟酵素的活動力變化非常少,皆是維持在處理高蛋白的高活動力,即使沒有餵食時也是如此。
 
Why would cats be so different? Well, compared to other carnivores, cats may not be so strange after all. A similar degree of metabolic "inflexibility" has also been reported in other carnivores such as barn owls and the rainbow trout.³⁴ ³⁵
 
為何貓會如此不同?和其他肉食動物比較起來,貓並非特別奇怪。在其他肉食動物身上,例如倉鴞和虹鱒 ,也可以看到類似的代謝能力「缺乏彈性」。
 
This limited metabolic flexibility in cats and other obligate carnivores likely represents an evolutionary adaptation to a consistently abundant supply of dietary protein. The moderately high and fixed activity of the urea cycle provides a safeguard against ammonia toxicity after ingestion of a high-protein meal. In addition, the high rate of amino acid catabolism allows for a readily available source of energy via direct oxidation or as a substrate for hepatic gluconeogenesis.
 
貓和其他絕對肉食動物的代謝彈性如此有限,可能代表的是進化適應力,因為環境中有穩定供應的高蛋白食物。相當高且固定的尿素循環活動力,提供安全保護以免氨毒素太高,在貓吃下高蛋白的肉之後。此外,高氨基酸分解率讓貓隨時可取得熱量,藉由直接的氧化,或是肝臟糖質再生的基質。
 
It is only when a cat is fed a lower protein diet - a condition that would never happen in the wild - that the high rate of protein catabolism becomes a disadvantage.
 
只有當貓吃下低蛋白質食物時-這種狀況永遠不會發生在野外的貓身上-高蛋白質分解率才會變成缺點。
 
Bottom Line
底線
 
·        Unlike omnivores such as dogs, pigs, rats or humans, cats have a limited ability to decrease the activity of the hepatic enzymes responsible for removing amino groups from the amino acids when fed a low protein diet.
 
不同於雜食動物,例如狗、豬、老鼠或人類,當你餵貓吃低蛋白食物時,貓降低肝臟酵素活動力的能力有限;肝臟酵素負責移除氨基酸中的氨基群。
 
·        Because these feline hepatic enzyme systems are constantly active, a fixed amount of dietary, or muscle, protein will always be catabolized for energy no matter how much energy in the form of carbohydrate or fat the cat ingests.
 
因為這些貓科的肝臟酵素系統一直都是處於高活動力,固定分量的食物或肌肉蛋白質會被分解以做為熱量,不管貓從食物中吃下多少來自於碳水和脂肪的熱量。
 
·        In addition, neither fat nor carbohydrates can be directly converted to amino acids to be made into protein. In this regard, the carnivorous cat is similar to omnivores.
 
此外,脂肪和碳水都無法被直接轉換成氨基酸以製造出蛋白質。就這點而言,肉食動物和雜食動物是類似的。
 
·        Overall, this explains why muscle wasting can occur so quickly in the older, geriatric cat, which becomes ill or develops a poor appetite or is fed a low-protein diet.
 
整體而言,本文解釋了為什麼老貓生病、胃口不好,或是吃低蛋白質食物時,肌肉流失可能會很快發生的原因。
 
Dr Mark E. Peterson has been deeply involved in clinical research for over 35 years, and remains at the forefront of the science that advances the study and knowledge of endocrine diseases of cats. He was the first veterinarian to document hyperthyroidism in cats (1979) and the first to treat hyperthyroid cats with radioiodine (in 1980). In addition to hyperthyroidism, Dr. Peterson was the first to document a number of "new" diseases in cats, including acromegaly, hypoparathyroidism, insulinoma, and Addison's disease. Dr. Peterson is director of the Animal Endocrine Clinic in New York City, a specialty referral hospital devoted exclusively to the care of cats and dogs with endocrine disease.
 
本文作者獸醫馬克.彼得森(Mark E. Peterson)醫生積極投入臨床研究已經超過三十五年,是貓的內分泌疾病研究和知識的權威。他是第一位記錄貓甲狀腺亢進的獸醫(1979),也是第一個用放射性碘治療甲亢貓的獸醫(1980). 除了甲亢以外,彼得森醫生也是第一個記錄貓的「新」疾病的醫生,包括肢端肥大症、副甲狀腺功能低下、胰島素瘤和愛迪生氏病。彼得森醫生是紐約市動物內分泌診所負責人,那是一間專科轉診醫院,只有照顧內分泌疾病的貓和狗。
 
  1. G Perez-Camargo, “Cat nutrition: What is new in the old?” Compendium for Continuing Education for the Practicing Veterinarian 26, Suppl 2A, 5-10.
  2. D Laflamme, “Nutrition for Aging Cats and Dogs and the Importance of Body Condition,” Veterinary Clinics of North America: Small Animal Practice 35, 2005, 713-742.
  3. G Pérez-Camargo, “Feline Decline in Key Physiological Reserves: Implication for Mortality,” Proceedings of the Nestlé Purina Companion Animal Nutrition Summit: Focus on Gerontology, St. Louis, MO, 2010, 6-13.
  4. S Fujita and E Volpi, “Nutrition and Sarcopenia of Ageing,” Nutrition Research Reviews 17, 2004, 69-76.
  5. D Paddon-Jones, KR Short, WW Campbell,  et al, “Role of Dietary Protein in the Sarcopenia of Aging,” The American Journal of Clinical Nutrition 87, 2008, 1562S-1566S.
  6. KR Short and KS Nair, “Mechanisms of Sarcopenia of Aging,” Journal of Endocrinological Investigation 22, Suppl 5, 1999, 95-105.
  7. RR Wolfe, “Sarcopenia of Aging: Implications of the Age-related Loss of Lean Body Mass,” Proceedings of the Nestlé Purina Companion Animal Nutrition Summit: Focus on Gerontology, St. Louis, MO, 2010, 12-17.
  8. SE Little, “Evaluation of the Senior Cat with Weight Loss,” In: SE Little, (ed), The Cat: Clinical Medicine and Management, Philadelphia, Elsevier Saunders, 2012, 1176-1181.
  9. AH Sparkes, "Feeding Old Cats - An Update on New Nutritional Therapies," Topics in Companion Animal Medicine, no. 26, 2011, 37-42.
  10. AR Patil, C Cupp and G Pérez-Camargo, “Incidence of Impaired Nutrient Digestibility in Aging Cats,” Nestlé Purina Nutrition Forum Proceedings 26, 2003, Suppl 2A, 72.
  11. JJ Wakshlag, "Dietary Protein Consumption in the Healthy Aging Companion Animal," Proceedings of the Nestlé Purina Companion Animal Nutrition Summit: Focus on Gerontology, St. Louis, MO, 2010, 32-39.
  12. KL Gross, RM Yamka, C Khoo, et al, “Macronutrients,” In: MS Hand, CD Thatcher, RL Remillard, R Roudebush, BJ Novotny, (eds), Small Animal Clinical Nutrition, Mark Morris Institute, 2010, 49-105.
  13. KP Davy, T Horton, BM Davy, et al, “Regulation of Macronutrient Balance in Healthy Young and Older Men,” International Journal of Obesity and Related Metabolic Disorders 25, 2001, 1497-1502.
  14. J Galgani and E Ravussin, “Energy Metabolism, Fuel Selection and Body Weight Regulation,” International Journal of Obesity 32, Suppl 7, 2008, S109-119. 
  15. T Brody, Nutritional Biochemistry. Second Edition, Academic Press. 1998.
  16. New Oxford Dictionary of English, Oxford University Press, 2001.
  17. JM Berg, JL Tymoczko and L Stryer, “Protein Turnover and Amino Acid Catabolism,” Biochemistry, 5th edition, New York, WH Freeman, 2002.
  18. WE Mitch, “Mechanisms Accelerating Muscle Atrophy in Catabolic Diseases,” Transactions of the American Clinical and Climatological Association 111, 2000, 258-269.
  19. AL Riis, JO Jørgensen, S Gjedde, et al, “Whole Body and Forearm Substrate Metabolism in Hyperthyroidism: Evidence of Increased Basal Muscle Protein Breakdown,” American Journal of Physiology: Endocrinology and Metabolism 288E, 2005, 1067-1073.
  20. A Myrcha and J Pinowski, "Weights, Body Composition and Caloric Value of Post-juvenile Molting European Tree Sparrows," Condor, no. 72, 1970, 175–178.
  21. JF Vondruska, "The Effect of a Rat Carcass Diet on the Urinary pH of the Cat," Companion Animal Practice, no. 1, 1987, 5-9.
  22. SD Crissey, KA Slifka and BA Lintzenich, "Whole Body Cholesterol, Fat, and Fatty Acid Concentrations of Mice (Mus domesticus) Used as a Food Source," Journal of Zoo and Wildlife Medicine, no. 30, 1999, 222-227.
  23. National Research Council, “Proteins and Amino Acids,” In: Nutrient Requirements of Dogs and Cats, Washington, DC: National Academies Press, 2006, 111-145.
  24. ML MacDonald, QR Rogers and JG Morris, "Nutrition of the Domestic Cat, A Mammalian Carnivore," Annual Review of Nutrition, no. 4, 1984, 521-562.
  25. JG Morris, "Idiosyncratic Nutrient Requirements of Cats Appear to be Diet-induced Evolutionary Adaptations," Nutrition Research Reviews, no. 15, 2002, 153-168.
  26. WH Hendriks, “Protein Metabolism in the Adult Domestic Cat (Felis catus),” PhD Thesis, 1996.
  27. B Hamper, J Bartges, C Kirk, et al, “The Unique Nutritional Requirements of the Cat: A Strict Carnivore,” In: SE Little, ed., The Cat: Clinical Medicine and Management,St. Louis: Elsevier Saunders, 2012, 236-242.
  28. IC Kettelhut, MC Foss and RH  Migliorini, “Glucose Homeostasis in a Carnivorous Animal (Cat) and in Rats Fed a High-protein Diet,” American Journal of Physiology 239, 1980, R437-440.
  29. QR Rogers, JG Morris and RA Freedland, “Lack of Hepatic Enzymatic Adaptation to Low and High Levels of Dietary Protein in the Adult Cat,” Enzyme 22, 1977, 348-356.
  30. AS Green, JJ Ramsey, C Villaverde, et al., "Cats are Able to Adapt Protein Oxidation to Protein Intake Provided Their Requirement for Dietary Protein is Met," The Journal of Nutrition, 2008, 1053-1060.
  31. JC Waterlow JC, “The Mysteries of Nitrogen Balance,” Nutrition Research Reviews 12, 1999, 25-54.
  32. RW Rosebrough, NC Steele and JP McMurtry, “Effect of Protein Level and Supplemental Lysine on Growth and Urea Cycle Enzyme Activity in the Pig,” Growth 47, 1983, 348-260.
  33. RT Schimke, “Adaptive Characteristics of Urea Cycle Enzymes in the Rat,” Journal of Biological Chemistry 237, 1962, 459-68.
  34. ML Walton, “Metabolic Effects of Feeding a High Protein/low Carbohydrate Diet as Compared to a Low Protein/high Carbohydrate Diet to Rainbow Trout Salmo Gairdneri,” Fish Physiology and Biochemisty 1, 1986, 7-15.
  35. MR Meyers and KC Klasing, “Low Glucokinase Activity and High Rates of Gluconeogenesis Contribute to Hyperglycemia in Barn Owls (Tyto alba) After a Glucose Challenge,” Journal of Nutrition 129, 1999, 1896-1904.


 


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