: 大多数猫咪都比较喜爱半生熟，甚至是全生的蛋黄（其实是OK的，因猫咪肠胃内的酸性特
: 别高，所以牠们对沙门氏菌的抵抗力比人类强）。但切记一定要将蛋白煮熟，因蛋白中含
: 有抗生物素蛋白质（Avidin），若未经煮熟就进食，可能会破坏猫咪体内的生物素（
: Biotin，即维生素B群的一种）。
回应有人说ok，我实在很懒得去翻教科书…
以下内容节自：
《Canine and Feline Nutrition 3 edition： A Resource for Companion Animal
Professionals (2010)》
首先是p.33谈biotin的部分：
"Eggs provide a very rich source of biotin,
but egg white contains a compound called avidin,
which binds biotin and makes it unavailable for absorption.
Thoroughly cooking eggs destroys avidin and
allows the biotin in the yolk to be used."
这里明白说到avidin会造成biotin无法被吸收，
将蛋白煮熟则会破坏avidin，让biotin可以被吸收。
(小弟注：因为avidin对biotin具高亲和力，
蛋黄中的biotin会被生蛋白中的avidin绑住，造成蛋黄中的biotin无法被吸收。
而如果猫摄入的avidin可以绑住的biotin量大于蛋黄中含有的biotin量时会发生什么事，
我想就不用我解释了。
所以有人说什么蛋黄中含有大量biotin可以一并吃就没问题，听听就好)。
同时，在p.283中提到：
"Although egg is a high-quality food ingredient, the white of the egg
(albumen) contains several inhibitory substances that alter the metabolism
of specific nutrients.The two most important are avidin, an inhibitor of
biotin absorption, and a compound that interferes with the action of the
pancreatic protease, trypsin (trypsin inhibitor). The antitryptic activity
of egg white is a characteristic that is much less well documented in
current literature than avidin, yet one that has the potential for
causing severe nutritional imbalances."
这里明白说明了虽然鸡蛋是高营养价值食物，但蛋白(白蛋白)含有数种抑制物质，
可以改变特定营养素的代谢，其中最重要的两个，一个就是avidin，
另一个就是trypsin(胰蛋白酶抑制蛋白)，而trypsin可能导致严重的营养失衡。
在p.283中，对avidin进一步做叙述：
"Avidin is a protein that is a secretory product of the hen’s oviduct
and is subsequently deposited in the albuminous portion of the egg.
When consumed, avidin combines with dietary biotin in the intestine
and prevents its absorption."
这里是说明avidin会在肠道内阻碍biotin被吸收(因为被avidin绑走了)。
同时，在p.283中说明到：
"Practically speaking, potential risk for biotin deficiency will only
occur if an owner supplements the pet’s food with only the white of
the raw egg. As in other species, signs of biotin deficiency in dogs
and cats include dermatitis, loss of hair and poor growth rate."
这里特别说明了“如果饲主‘只有将’蛋白作为宠物食物的‘补充’”，
才有可能出现biotin缺乏的问题，
但这里有个重点是，因为这里的“宠物食物”已经拥有足量的biotin了，
而生蛋白只是作为“补充”(蛋白质上的补充)，
但若饲主是在做自制生鲜食时，“同时加入了生蛋白和生蛋黄”呢？
换言之，若生蛋白不是作为补充，而是作为“主要提供蛋白质的材料之一”，
那么仍然要担心宠物可能出现biotin缺乏的问题。
p.283继续谈到蛋白中含有的trypsin(胰蛋白酶抑制蛋白)：
"EGG WHITE TRYPSIN INHIBITOR
The white of the egg also contains another potentially damaging
inhibitory substance. This substance is actually a group of proteins that
have antitryptic activity. The antitryptic effect of feeding raw egg white
has received less attention than avidin, yet its capacity for causing
nutritional problems in pets is potentially much greater."
这里提到胰蛋白酶抑制蛋白通常比avidin少被关注，
但胰蛋白酶抑制蛋白可能会引起比avidin更严重的营养问题。
"Early studies reported that dogs fed as little as two raw egg whites
per day in their food exhibited loose stools, and when the amount was
increased further, chronic diarrhea and weight loss developed. Dried
(uncooked) egg white was found to be just as active in causing diarrhea
and weight loss as was fresh, raw egg white. The utilization
of raw egg white protein (as determined by apparent digestibility)
was reported to be only 58.6%."
这里提到对狗的早期研究发现(没有提到样本体重与数量)，
每天喂狗吃两颗生蛋白，就会开始出现排稀便的情况，
如果数量再增加，就会开始出现慢性腹泻与体重减轻的情况，
即便是干燥的生蛋白，也和新鲜生蛋白一样具有导致体重减轻和腹泻的作用。
而生蛋清蛋白质只有58.6%的利用率(小弟注：熟蛋白通常有88%以上的利用率)
"Subsequent feeding studies and in vitro tests of protein digestibility
confirmed that the factor responsible for these effects was a group of
trypsin inhibitor proteins found in the white of the egg. Egg white trypsin
inhibitor reduced a food’s protein digestibility when included at just 7% of
the diet, and a linear relationship was reported between the amount of egg
white trypsin inhibitor and loss of protein digestibility."
这里提到随后的研究证实了生蛋白中的一组胰蛋白酶抑制蛋白，
会降低食物中的蛋白质消化率。
同时，在p.284中继续提到：
"Similar to avidin, heat treatment denatures the trypsin inhibitor of egg
white and allows utilization of the protein in the egg white and of other
protein sourcesin the food.
For example, the most recent study with dogs confirmed that the inclusion of
raw (dried) egg in the diets of growing puppies impaired diet digestibility
and caused chronic diarrhea and weight loss in all of the puppies during a
14-day feeding period.However, when the same amount of heat-treated dried egg
white was included in the food, stools were normal, the puppies showed
healthy growth rates, and diet digestibility coefficients were improved.
Laboratory analysis of each diet showed that trypsin inhibitor activity was
significantly reduced in the heat-treated egg white, when compared with raw
egg white."
这里提到胰蛋白酶抑制蛋白和avidin一样，会因为热处理而变性，
而使得蛋白中的蛋白质和食物中的其他蛋白质可以被正常利用。
后续提到最近对狗的研究亦表明，在连续14天对狗喂食含有干燥生蛋的食物时，
所有狗都出现慢性腹泻以及体重减轻的情况，
但若是喂食煮熟的同等量干燥生蛋白时，所有狗的排便都正常，
成长速率、消化速率也都获得改善。
实验室针对每一次饮食的分析也都呈现了，
经热处理的蛋白在胰蛋白酶抑制蛋白比生蛋白具有胰蛋白酶抑制蛋白活性的显著降低。
"Again, the practical relevance of this knowledge to the feeding of companion
animals is that if an owner insists on adding egg products to a pet’s food,
the eggs should always be cooked thoroughly before feeding.This is necessary
to denature both avidin and the trypsin inhibitors present in the egg white.
In addition, feeding raw eggs is not recommended due to the risk of bacterial
contamination. A general guideline is to limit eggs to just one or two cooked
eggs per week for a medium or large dog. This level should not result in a
dietary imbalance and will not affect energy consumption to the degree of
causing weight problems."
这里提到，如果饲主坚持要将鸡蛋加入宠物的饮食中，
鸡蛋则应该得煮熟，这对avidin和胰蛋白酶抑制蛋白的变性是必须的。
同时也提到“对中型犬或大型犬的指导方针是，每周只提供1~2颗煮熟鸡蛋。”
教科书上从来没提到生蛋白和生蛋黄一起吃就没关系，
而若对中型犬和大型犬来说，每周1~2颗的煮熟鸡蛋才适量，
那么对通常没有中型犬体型的“猫”来说，
如果我们在每周(或每月)的自制生食中对应应加入的生蛋黄颗数，
加入同等量的生蛋白，会发生什么事，应该大家心里都明白了。
总结以上，生蛋白中对猫来说具有风险的不止是avidin，
还有胰蛋白酶抑制蛋白，无论如何，请不要喂猫咪吃生蛋白。