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玛氏宠物护理学院

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Science Head
科研主管

Dr Lucille Alexander has over 9 years experience working in the field of nutrition across a wide variety of pet species including cat, dog, horse, bird and fish at WALTHAM®. Since joining WALTHAM Lucille has been involved in research that has generated over 20 peer reviewed publications.
Lucille Alexander
博士在威豪®宠物中心从事营养学领域的研究已经有超过9年的历史,研究对象包括多种宠物,包括猫、狗、马、鸟与鱼等。加入威豪后, Lucille全心投入在科研领域,迄今已发表期刊论文20多篇。

Energy Requirements - Key Message
能量需求-关键信息

WALTHAM® has contributed to the understanding of the energy requirements of cats by:
通过以下方式,威豪®成功地促进了人们对猫的能量需求的认识:
• Showing that the energy requirements of cats are lower than previously thought, and the relationship between energy requirement and body size is not linear.
• Generating insight into the further reduction of energy requirements seen in neutered adult cats.
• Demonstrating that the energy requirement of kittens is less than previously thought, and is further reduced by neutering.
• Generating insight into energy storage in neutered kittens.
• 证明猫的能量需求比以前人们所认为的要低,并且猫的能量需 求量与其体积之间并不具有线性关系;
• 在阉割后成年猫能量需求更低这一方面形成创新性见解;
• 证明幼猫的能量需求量低于以前所认为的,并且在阉割后的能 量需求量进一步降低;
• 在阉割后幼猫的能量储备方面形成创新性见解。

 

Background
背景

The amount of dietary energy an animal needs to meet its energy requirement has to account for:
动物为满足其能量需求而需要的饮食能量必须满足下列各项需求:

Basal metabolic rate
基础代谢率
• The energy expended to maintain basic physiological functions (including heart beat, respiration, and kidney function). It is usually measured as resting metabolic rate – that is, the energy expended to maintain the body whilst lying down and awake.
• 动物为保持基本生理功能(包括心率、呼吸与肾功能)所耗费 的能量。基础代谢率通常通过休息代谢率测定——即动物在躺卧且清醒状态下维持正常身体功能所耗费的能量。
Thermogenesis
生热作用
• The energy expended to ingest, digest, absorb, and assimilate food.
• The energy expended to cope with stress, including changes in environmental temperature.
• 动物摄入、消化、吸收与同化食物所消耗的能量;
• 动物应对压力(包括环境温度变化)所消耗的能量

 

Activity
活动

• The energy expended during movement and exercise.
• 动物活动和锻炼所消耗的能量。

Basal metabolic rate depends on factors including body weight, body composition, age, and hormonal status. Thermogenesis can vary widely and results in daily fluctuations in energy requirement.

基础代谢率的决定因素包括体重、身体组成、年龄与体内激素状况。生热作用变化的 幅度可能非常大,并会导致动物每日能量需求量方面的波动。

Energy expenditure (or requirements) can be measured as heat production (using direct calorimetry). This is affected not only by body weight, but also by body surface area. Body weight that has been corrected mathematically to take account of surface area is known as metabolic body weight (MW), and this allows a comparison of the energy requirements of animals that differ in body size.

能量消耗(或需求量)可以通过热产生的方式测定(使用直接量热法)。能量消耗不 仅受到体重的影响,而且还受到身体表面积的影响。经过数学校正以反映身体表面积的体重被称为代谢体重,通过代谢体重可以比较不同体积的动物在能 量需求量方面的差异。

The body weight of healthy mature domestic cats varies from about 2.5 kg to 6.5 kg. For a long time it was assumed that, with such a narrow range of body weight, feeding cats of different sizes was straightforward and linear in nature.

健康成年家猫的体重约为2.5公斤-6.5公斤。在很长时间内,人们一直认为,由于家 猫的体重范围较小,因此喂食不同体积的猫是一件简单的事情,并且喂食量也与其体重呈线性关系。

 

Why WALTHAM® is Interested
为何威豪®有兴趣从事该领域的研究

A thorough understanding of energy requirements is essential in order to produce accurate feeding guidelines to help owners feed their cat appropriately and prevent under-nutrition or obesity.
全面认识猫的能量需求具有至关重要的意义,这有助于制定出准确的喂食指南以帮助 猫的主人能够以适当方式喂养猫,从而防止营养不良或肥胖的现象出现。

However, the energy requirements of the adult cat for maintenance are still largely uncharacterised and much debated. In 1986, the NRC recommended a linear allowance for relatively inactive cats that treated each kg body weight of small cats and large cats the same (NRC 1986). This was updated in 2006 to provide slightly less energy per kg bodyweight for overweight cats (NRC 2006). However, much variability was still evident in the available data.

但是,目前对成年猫在体重维持期的能量需求基本上尚未确定,而且仍存在诸多争议 。1986年,美国国家研究委员会针对相对不活跃的猫给出了线性建议能量供给量,该建议供给量不区分大猫和小猫,均以公斤体重的方式表示(美国国家 研究委员会, 1986年)。2006年,美国国家研究委员会对上述建议供给量进行了更新,从而略微下调了体重超重的猫的每公斤体重对应的建议能量供给量 (美国国家研究委员会,2006年)。然而,现有数据明确表明,在这方面仍然存在很大的不确定。

 

Approach
方法

Over time, WALTHAM® has undertaken a great many feeding studies of cats and routinely collects body weight data. This provides a unique and sizeable dataset for analysing the effect of body size on the amount of food required to maintain body weight, based on the premise that cats which are maintaining their body weight have an energy intake equivalent to energy requirement.

很长时间以来,威豪®已经开展了很多猫的喂养试验并在试验中例行性地收集了猫 的体重数据。这些数据为分析猫的体积对其维持体重所需食物量的影响提供了独特而充足的数据集(假设前提依据:猫在体重维持期的能量摄取量等于其 能量需求量)。

 

Discovery (Energy Requirement)
The energy requirement of cats is lower than previously thought, and the relationship with body size is not linear
发现与结论(能量需求量)
猫的能量需求量低于先前的观点,而且与能量需求量之间并不具有线性关系 。

Two studies have demonstrated a logarithmic (rather than linear) relationship between energy requirement and body weight in the cat.

两项研究均证明,猫的能量需求量与其体重之间呈现对数关系,而非线性关系。
Using the body weight data from 62 digestibility trials at WALTHAM®, a logarithmic relationship between energy requirement and body weight was found (Earle and Smith 1991). This research showed that larger cats have a lower energy requirement per unit of body weight than smaller cats (Figure 1. Earle and Smith 1991).

根据威豪®在62项消化性试验中所获得的体重数据,工作人员确立了猫的能量需求量与其体重之间的对数 关系(Earle与Smith, 1991年)。该研究显示,体积较大的猫的单位体积能量需求量低于体积较小的猫的单位体积能量需求量(图1:Earle与Smith, 1991 年)。

Reproduced from Earle KE, Smith PM. Digestible energy requirements of adult cats at maintenance. J Nutr 1991.121(11Supp):S45- 46
摘自Earle KE与Smith PM的“成年猫维持期阶段的消化能需求”;选自《营养学杂志》,1991年,121(11增刊): S45- 46

Figure 1: Mean ± SD digestible energy intake (kJ/kg body weight) of the adult cat at maintenance (Earle and Smith 1991)

 

图1:成年猫维持阶段的消化能摄入量(千焦/公斤体重)平均值 ±标准偏差(Earle与 Smith,1991年)

 

Subsequently, in collaboration with scientists in New Zealand, a meta- analysis of the data from 42 publications was conducted (Bermingham et al. 2010). The effect of body weight on maintenance energy requirements is shown in Figure 2. Energy requirements were found to be lower than those described by the NRC 2006 recommendations (Bermingham et al. 2010). The allometric equation for maintenance requirements in all cats was calculated with a back-transformed equation of 77.6 kcal/kg BW -0.711 (Bermingham et al. 2010). These data are important because meta-analysis is a powerful statistical tool, and the data were sourced from published literature (that is, not solely from the cats housed at WALTHAM®). This study therefore strengthens the body of data on the energy requirements of the cat.

2010年,威豪®与新西兰科学家共同合作对42份发表论文的数据进行了荟萃 分析(Bermingham等,2010年)。体重对维持阶段的能量需求量的影响如图2所示。上述分析的结果显示,猫的能量需求量低于美国国家研究委员会于2006 年所给出的建议值(Bermingham等,2010年)。所有猫为维持阶段所需能量的异速生长公式均采用逆转换公式77.6千卡/公斤体重-0.711进行计算 (Bermingham等,2010年)。荟萃分析是一种非常强大的统计工具,而且相关数据均系从各种出版文献(即并非只来自与威豪®所养护的猫的数据)中筛选出来,因此 上述数据具有非常重要的意义。该项研究也因而强化了身体的相关数据与能量需求之间的相互关系。

 

Reproduced from Bermingham EN, Thomas DG, Morris PJ, Hawthorne AJ. Energy requirements of adult cats. Br J Ntr 2010. 103 (8):1083-1093查看
摘自Bermingham EN、Thomas DG、Morris PJ与Hawthorne AJ的“成年猫的能量需求”;选自《英国营养学杂志》2010 年103(8):1083-1093。

Figure 2: Effect of body weight (BW) on the maintenance energy requirements of domestic cats (O; —), compared with the predicted requirements from the present study (– – –) and those predicted by the National Research Council (••••••) (Bermingham et al. 2010).

图2:体重对家猫在维持阶段的能量需求的影响(与当前研究以及 美国国家研究委员会所预测的能量需求量进行对比)(Bermingham 等,2010年)

 

Insight Generation (Neutered Cats)
The energy requirement of cats decreases after neutering
独特见解(阉割后的猫)
阉割后猫的能量需求量有所降低

Neutered cats are thought to be at particular risk of obesity. Data generated in a study at WALTHAM® showed that the energy requirement of adult female cats decreases after neutering. The 11 female cats (aged 2.6–6.2 years, mean 3.9 ± 1.5 years) were fed to maintain a constant body weight, and their energy intake decreased from a mean of 55.5 kcal/kg/day immediately post-neutering to 45 kcal/kg/day 12 months later (Harper et al. 2001).

阉割后的猫被认为特别容易出现肥胖现象。威豪®所进行的一项研究所得出的数据显示,成年雌猫在阉 割后的能量需求量有所降低。11只雌性猫(年龄为2.6–6.2周岁,平均年龄为3.9 ± 1.5周岁)在刚刚阉割后的能量摄取量平均值为55.5千 卡/公斤体重/天,但这一数字在12个月之后迅速降低为45千卡/公斤体重/天(Harper等,2001年)。

 

Discovery (Neutered Kittens)
The energy requirement of kittens is less than previously thought, and is further reduced by neutering

发现与结论(阉割后的幼猫)

幼猫的能量需求低于先前所设值,并且在阉割后进一步降低

Neutered cats are thought to be at particular risk of obesity. WALTHAM® undertook this post hoc analysis of data from a previous study to understand the effects of neutering on food intake, body weight, and changes in body composition in growing kittens.

阉割后的猫被认为特别容易出现肥胖现象。为了了解阉割对生长期的猫在食物摄取量 、体重以及身体组成变化方面所带来的变化,威豪®以先前一项研究所得出的数据为对象进行了此次事后分析。

In the study, the twelve pairs of 11-week-old female littermates were randomly assigned to either a neutered group (neutered at 19 weeks old) or an entire group (kept sexually entire) and offered free access to a dry diet until the age of 1 year (Alexander et al. 2011).

在该项研究中,研究人员将12对11周大的雌性同窝幼猫随机分配至阉割组(在19周大 时进行阉割手术)或未阉割组(保持完整性功能),然后在为期1年的试验过程中允许这些试验猫自由进食干猫粮(Alexander等,2011年)。
Food intake of the neutered kittens increased after neutering (P

阉割后的幼猫的食物摄取量在刚被阉割后有所增加(P<0.00001, 图3)。两组试验 猫在食物摄取量(每公斤体重)方面的差异在阉割后第10周达到最大值,此时阉割后的幼猫的平均食物摄取量比完整组小猫高17%(P=0.00014)。然后,被 阉割的幼猫的食物摄取量逐渐下降;到阉割后第18周,两组幼猫在食物摄取量方面的显著差异性已经消失。

Body weight of the neutered kittens increased after neutering (P

阉割后,被阉割幼猫的体重有所增加(P<0.00001, 图4)。在试验第52周时,被阉 割小猫的体重比完全组幼猫高24%(P<0.0001),前者的体况评分比后者高16.6%(P=0.0028)。

Reproduced from Alexander LG, Salt C, Thomas G, Butterwick R. Effects of neutering on food intake, body weight and body composition in growing female kittens. Br J Nutr. 2011 Oct;106 Suppl 1:S19-23. 查看

 

摘自:Alexander LG、Salt C、Thomas G与Butterwick R的“阉割对生长期雌性幼猫的食物摄取量、体重与身体组成的影响”。选自:《 英国营养学杂志》,2011年10月;106增刊1:S19-23。查看

Reproduced from Alexander LG, Salt C, Thomas G, Butterwick R. Effects of neutering on food intake, body weight and body composition in growing female kittens. Br J Nutr. 2011 Oct;106 Suppl 1:S19-23.查看

摘自:Alexander LG、Salt C、Thomas G与Butterwick R的“阉割对生长期雌性幼猫的食物摄取量、体重与身体组成的影响”。选自:《 英国营养学杂志》,2011年10月;106增刊1:S19-23。
网址:查看

Figure 3: Food intake and body weight of entire (open symbol) and neutered (shaded symbol) kittens, mean ± SD (Alexander et al. 2011). The time of neutering is shown by the vertical dotted line

图3:未阉割幼猫(以普通符号表示)与被阉割幼猫(以阴影符号表示)的食物摄取量与体重对比,平均值< style="line- font- family: arial, helvetica, sans-serif;">±< style="line- font-family: arial, helvetica, sans-serif;">标准偏差< style="line- font-family: arial, helvetica, sans-serif;">(Alexander< style="line- font-family: arial, helvetica, sans- serif;">等,< style="line- font-family: arial, helvetica, sans-serif;">2011< style="line- font-family: arial, helvetica, sans-serif;">年< style="line- font-family: arial, helvetica, sans-serif;">)

Whilst maintaining an ideal body condition score the entire kittens consumed 93% of their theoretical intake at 26 weeks of age, and 79% at 52 weeks of age. This suggests that the recommendations for energy requirement in kittens are inappropriate.

在保持理想体况评分的条件下,未阉割幼猫在年龄为26周与52周大时的食物摄取量分 别为理论摄取量的93%和 79%。这一结果表明,美国国家研究委员会所给出的小猫建议能量需求量值并不适当。

Neutered kittens consumed similar amounts of energy to the entire kittens from 18 weeks post-neutering, while their body weight, body condition score and percentage fat continued to increase. This suggests that neutered kittens have a reduced metabolisable energy requirement compared with entire kittens.

在被阉割后第18周,被阉割幼猫的能量消耗量与未阉割幼猫基本相同,但前者的体重 、体况评分与脂肪含量均继续增加。这表明,被阉割幼猫的代谢能需求量低于未阉割幼猫。

This study suggests that the current recommendation for the energy requirement of kittens appears to be too high. In particular, neutered kittens should not be fed ad libitum, rather they should be fed to maintain an ideal body condition score (Alexander et al. 2011).

该项研究表明,美国国家研究委员会所给出的幼猫的能量需求量值似乎过高。特别应 该指出,被阉割幼猫不应被随意喂食,而应以能够保持其理想体况的评分为标准进行喂养 (Alexander等,2011年) 。

 

Insight Generation (Neutered Kittens)
Neutered kittens store more energy and have lower energy requirements than entire kittens
形成见解(被阉割幼猫)
被阉割幼猫的能量储备高于、但能量需求量低于未阉割小猫。

Neutering of female kittens at 19 weeks of age resulted in higher energy intake (Alexander et al. 2011), but the weight gain and especially fat percentage seemed out of proportion with the differences in energy intake. This suggested reduced energy requirement for maintenance and/or tissue accretion after early neutering.

被实施阉割手术(19周大时)后,雌性幼猫的能量摄取量有所增加(Alexander等, 2011年),但其体重,特别是体内脂肪含量百分比似乎与能量摄取量差值之间不成比例。这表明,在低龄时被阉割,这些猫体内维持体重所需的能量和/或 组织生长有所降低。

Using factorial analysis, the metabolisable energy (ME) requirement for tissue accretion and maintenance was calculated in the same kittens from 11–52 weeks of age (Alexander et al. 2011). This analysis was a collaboration with Ludwig-Maximilians-Universität, Munich, Germany.

研究人员采用因子分析的方法对11-52周大同种小猫组织生长与体重维持的代谢能需 求量进行了计算(Alexander等,2011年)。该分析系与德国路德维希-马克西米利安-慕尼黑大学共同进行。

Dual energy x-ray absorptiometry (DXA) data were transformed to provide values for body protein and fat, then the energy content in the body was calculated from these data using 9.4 kcal/g fat and 5.7 kcal/g protein. The composition and energy content of the gained tissue was calculated using the difference in the amount of nutrient in the body at each consecutive DXA measurement and dividing it by the difference in body weight and time. The daily energy accretion in tissue was presumed to be the net requirement for tissue accretion. The utilisation efficiency of ME was taken from the data on fattening pigs (0.56 for protein; 0.74 for fat). The resulting values for each individual kitten were subtracted from the energy intake of the individual kitten in the study and the remaining values were assumed to represent the maintenance requirement.

研究人员对双能X射线法所得出的数据进行转换以获得猫体内的蛋白质与脂肪含量值 ,然后根据这些数据计算出猫的体内能含量(按照9.4千卡/克脂肪与5.7 千卡/克蛋白质的标准)。研究人员将通过双能X射线连续测定值所得出的体内营 养素含量之间的差值除以猫的体重以及时间的差值,从而计算出猫体内被研究的组织的构成与能含量。组织的每日能量增长值即被视为该组织生长的能量 需求净值。代谢能的利用效率采用商品猪的相关数据得出(蛋白质:0.56;脂肪:0.74)。然后,研究人员用研究期间每只小猫的能量摄取量减去其对应的 身体组织能量需求净值,所得出的值即表示维持体重的能量需求值。

Maintenance requirements and requirements for tissue accretion differed significantly between the neutered and entire kittens between 31 and 52 weeks of age. The mean daily ME requirement for tissue accretion and maintenance for neutered kittens was 180 ± 36 and 59 ± 18 kcal/day compared with 115 ± 41 and 99 ± 30 kcal/day for entire kittens (Alexander et al. 2011).

31-52周大的阉割幼猫与未阉割幼猫维持体重所需的能量需求量以及组织生长的能量 需求量之间均存在显著差异。阉割幼猫组织生长与体重维持每日所需的代谢能平均值分别为180 ± 36与59 ± 18千卡/天,而未阉割幼猫组 织生长与体重维持每日所需的代谢能平均值分别为115 ± 41与99 ± 30千卡/天(Alexander等,2011年)。

These neutered female colony cats stored more energy and had lower maintenance energy requirements than entire female colony cats and lower energy requirements than seen in the published literature (Alexander et al. 2011). Early neutering may decrease maintenance energy requirements even further than neutering of adults.

试验中的雌性阉割猫组的储备能量值高于未阉割雌性猫组,但前者的维持体重所需的 能量却低于后者,而且前者的能量需求量也低于已发表文献中的相应数据(Alexander 等,2011年)。低龄阉割可能比成年时阉割更有助于降低维持体重所 需的能量。

 

 

Protein - Key Message
蛋白质-关键信息

WALTHAM® has contributed to the understanding of protein metabolism and dietary protein requirement of the adult cat by:
通过以下方式,威豪®成功地促进了人们对成年猫的蛋白质代谢与饮食蛋白质需求 的认识:

• Showing that adult cats need about 10% protein energy in their diet to maintain nitrogen balance.
• Demonstrating that the protein metabolism of the cat adapts when fed above minimal requirements demonstrating a degree of metabolic flexibility.
• 证明成年猫维持体内氮平衡所需的蛋白质,大约等于其饮食能 含量的10%;
• 证明在被喂食上述最低需求量的蛋白质时,猫的蛋白质代谢作 用具有自动适应的能力,从而表现出一定的代谢灵活性。

 

Background
背景

Protein consists of amino acids that are classified as essential (because they can’t be synthesised by the body) or non-essential (because the body can synthesise them).
Dietary protein must provide sufficient amino acids to satisfy the body’s metabolic requirement. Aspects of this can be measured as:

蛋白质由必需氨基酸(因为身体无法合成这些氨基酸)和非必需氨基酸(因为身体能 够合成这些氨基酸)所组成。饮食中的蛋白质必须能够提供足够的氨基酸以满足身体的代谢需求。身体内蛋白质的代谢作用可以通过以下方式测定:

• Protein turnover (synthesis, breakdown, inter- conversions).
• Synthesis of other nitrogen-containing compounds and urea.
• Protein oxidation.
• Gluconeogenesis (the synthesis of glucose from non- carbohydrate carbon sources including amino acids).
• 蛋白质转换(合成、分解与相互转化)
• 其他含氮化合物与尿素的合成
• 蛋白质氧化
• 葡萄糖异生(非碳水化合物碳源(包括氨基酸)合成葡萄糖)

Dietary protein requirements are also dependent on energy intake, life- stage (growth increases the requirement), lifestyle (physical activity increases the requirement), and other factors such as disease.
饲粮中的蛋白质需求量还取决于能量摄取量、生命阶段(生长期的蛋白质需求量有所 增加)、生活方式(身体活动会导致蛋白质需求的增加)以及其他因素(如疾病)。

Compared with other species, the cat has a higher dietary protein requirement (NRC 2006). This has been attributed to a lack of metabolic flexibility, with less efficient adaption of feline hepatic nitrogen catabolic enzymes to dietary protein intake (Rogers et al. 1977).

与其他物种相比较,猫的饲粮蛋白质需求量较高(美国国家研究委员会,2006年)。 这是因为猫的身体的代谢灵活性较低以及猫肝脏中的但降解酶对通过饲粮摄取的蛋白质的适应效率较低的缘故(Rogers等,1977年)。

 

Why WALTHAM® is Interested
为何威豪®有兴趣从事该领域的研究

Understanding the protein requirements and protein metabolism of the cat, an obligate carnivore, is fundamental to providing the right nutrition.
了解猫(专性肉食动物)的蛋白质需求量与蛋白质代谢作用对于为其提供适当的营养 而言是必不可少的环节。

 

Approach
方法

WALTHAM® investigated the protein requirements of adult cats for maintenance using the nitrogen balance technique. The metabolic flexibility of the cat was examined by measuring aspects of its protein metabolism, in an effort to understand why the cat needs so much protein.

威豪®采用氮平衡技术研究成年猫维持体重所需的蛋白质量。为了了解猫对蛋白质需求量较大的原因 ,研究人员采用采用测定相关参数的方式对其蛋白质代谢进行研究。

 

Discovery (Protein Requirement)
Adult cats need about 10% of their dietary energy to be provided by protein
发现与结论(蛋白质需求量)
猫饮食能含量中,大约10%来自于蛋白质。

The nitrogen balance technique measures nitrogen intake and nitrogen excretion. When these are equal, the animal is considered to be consuming sufficient protein to meet its needs for maintenance. Nitrogen balance is negative during fasting or protein malnutrition, and is positive in growing animals.

氮平衡技术能够测量出氮摄取量与氮排泄量。当两者相等时,则认为动物所消耗的蛋 白质足以满足其维持需求。在空腹或蛋白质营养不良时,氮平衡为负数形式;生长期动物体内的蛋白质平衡为正数。

A study at WALTHAM® showed that when all essential amino acids were present at more than adequate concentrations, about 12.5% protein in the diet was required to maintain nitrogen balance in adult cats (Burger et al. 1984). This is equivalent to about 10% dietary energy as protein (Burger 1993). This study is pivotal to the literature on the crude protein requirement of the cat, and forms the basis of the NRC recommendation (NRC 2006).

威豪®所进行的一项研究表明,在所有必需氨基酸含量均大于适当浓度条件下,成年猫的饮食中大约 需要提供12.5%的蛋白质以维持其体内的氮平衡(Burger等,1984年)。该值相当于全部饮食能量的10%(应由蛋白质供应)(Burger 1993)。该项研究对 于了解猫对粗蛋白需求量具有至关重要的意义,并且成为美国国家研究委员会所制定的建议值的基础(美国国家研究委员会, 2006年)。

WALTHAM® also undertook some preliminary investigations on the amino acid requirements of the adult cat (Burger and Smith 1990).

同时,威豪®还就成年猫的氨基酸需求量进行了部分初步研究(Burger与 Smith,1990年)。

 

Discovery (Protein Metabolism)
The protein metabolism of the cat adapts to moderate-to-high levels of dietary protein as in other species
发现与结论(蛋白质代谢作用)
与其他物种相同,猫的蛋白质代谢作用能够使其对含量为中等至较高的饮食 蛋白质具有适应性。

Whole-body techniques often used in other species, including humans were applied to cats. These techniques included protein turnover (using a tracer), macronutrient oxidation (using indirect calorimetry), and urea kinetics (using a tracer). The nutritionally-complete diets were designed to provide moderate (20–35% of energy) and higher (52–70% of energy) levels of protein.

研究人员采用其他物种(包括人)常用的全身测量方法对猫进行检测。这些方法包括 蛋白质转换(使用示踪剂)、宏量营养素氧化(使用间接测热法)以及尿素动力学(使用示踪剂)。研究人员设计出营养成分完整的饮食以提供含量中等 (20–35%能量)至较高(52–70%能量)的蛋白质。

 

In collaboration with Prof Joe Millward (University of Surrey) and Dr Gerald Lobley (Rowett Research Institute, Aberdeen), feline protein turnover was found to adapt to dietary protein intake when fed above minimal requirements (Russell et al. 2003). This was the first time whole body protein turnover had been measured in the cat.

通过与英国萨里大学的Joe Millward教授以及亚伯丁罗维特研究所的Gerald Lobley 医生合作,威豪®确 定出了猫在以上述最低需求量标准喂食的条件下其体内为适应饮食蛋白质摄取量而进行的蛋白质转换量(Russell等,2003年)。这是首次对猫的全身蛋白 质转换情况进行测定。

Feline amino acid oxidation was also correlated with protein intake (Russell et al. 2002). This study was in collaboration with Peter Murgatroyd (University of Cambridge), and was the first time calorimetry had been used to measure protein oxidation in the cat.

猫的氨基酸氧化与蛋白质摄取之间也具有相关性(Russell 等,2002年)。该项研究由 威豪与剑桥大学Peter Murgatroyd共同实施,也是首次采用量热法对猫的蛋白质氧化情况进行测定。

A study of feline urea kinetics in collaboration with Prof Joe Millward (University of Surrey) and Dr Gerald Lobley (Rowett Research Institute, Aberdeen) found that urea production was related to dietary protein level (Russell et al. 2000). However, there was a low level and lack of nutritional sensitivity of urea entry and hydrolysis into the gut, and subsequent retention of urea nitrogen for anabolism (Russell et al. 2000). This was the first time urea kinetics had been measured in the cat.

威豪®还与英国萨里大学的Joe Millward教授以及亚伯丁罗维特研究所的Gerald Lobley医生合作开展 了猫的尿素动力学研究。研究结果发现,猫的尿素产量与其饮食中的蛋白质含量具有关联性(Russell等,2000年)。但是,研究发现,猫的肠道中的尿素 敏感度以及水解作用水平较低或缺失,并进而导致合成代谢的尿素氮含量的降低或缺失(Russell等,2000年)。这是研究人员首次对猫的尿素动力学特征 进行测定。

This research shows that, as with other species, these aspects of feline protein metabolism adapt to dietary protein intake when fed above minimal requirements demonstrating a degree of metabolic flexibility.
该研究表明,与其他物种相同,在被喂食上述最低需求量的蛋白质时,猫的蛋白质代 谢作用具有自动适应通过饮食摄入的蛋白质含量的作用。

 

 

Taurine - Key Message
牛磺酸-关键信息

WALTHAM® has contributed to the understanding of the taurine requirement of the cat by:
通过以下方式,威豪®成功地促进了人们对成年猫的牛磺酸需求的认识:

• Determining how much taurine is needed in canned and dry prepared pet foods.
• Demonstrating that kittens get taurine from the queen via the placenta.
• 测定了罐头与干性商业宠物饲粮中牛磺酸的含量;
• 证明幼猫能够通过胎盘从母猫身体中吸收牛磺酸。

 

Background
背景

Taurine (2-aminoethanesulfonic acid) is an end-product of sulphur amino acid metabolism that is widely distributed in animal tissues. Taurine is an essential nutrient for cats that must be present in the diet (Burger 1993). This is because the cat cannot synthesise sufficient taurine from dietary sulphur-containing amino acids, compounded by dependence on taurine for the formation of bile salts (being unable to conjugate bile acids to glycine) (Legrand- Defretin 1994).

牛磺酸(2-氨基乙磺酸)是含硫氨基酸(广泛分布与动物组织中)的终物质。牛磺酸是 猫的必需营养素,因此饮食中必须含有牛磺酸(Burger,1993年)。这是因为猫的体内无法通过饮食中的含硫氨基酸自行合成充足的牛磺酸,同时又需要牛 磺酸来合成体内的胆盐(缺少牛磺酸将无法实现胆酸与甘氨酸的连接)(Legrand-Defretin, 1994年)。

Taurine deficiency causes retinal degeneration (Hayes et al. 1975) as well as poor reproductive performance in breeding females, poor growth in kittens, and dilated cardiomyopathy in adult cats (Sturman et al. 1986; Pion et al. 1987; Pion et al. 1989).

牛磺酸缺乏会导致猫的视网膜变性(Hayes等,1975年)以及母猫的生殖能力减弱、小 猫的生长变差与成年猫的心肌病变(Sturman等,1986年;Pion等,1987年;Pion等,1989年)。

 

Why WALTHAM® is Interested
为何威豪®有兴趣从事该领域的研究

As an essential nutrient, taurine must be provided in prepared petfood at an adequate level, which requires an understanding of how much the cat needs.

牛磺酸是一种必需营养素,因此预制宠物饲粮中必须含有足够的牛磺酸,这就需要相 关人员对猫的牛磺酸需求量有比较详细的了解。
Initial studies into the taurine requirements of cats used semi-purified diets (Burger and Barnett 1982). Purified diets use simple ingredients in a highly available form (such as individual amino acids, soya protein, casein, dextrose) to enable the formulation of a diet with a defined nutrient profile – this is common practice when investigating the nutrient requirements of any species.

初期研究项目采用半纯化饲粮研究牛磺酸的需求量(Burger与Barnett ,1982年)。 纯化饲粮采用特别容易获得的简单营养成分形式(如单种氨基酸、大豆蛋白质、酪蛋白和右旋糖),从而是饲粮配方达到规定的营养成分标准 ——这是在研究任何物种的营养素需求时通常所采取的方法。

However, it became clear that prepared petfood needed separate consideration. Early data suggested that canned food needed to contain more taurine than dried diets to maintain normal plasma taurine concentrations (Pion et al. 1989).

然而,人们渐渐明确认识到,预制宠物饲粮在这方面还需要特别考虑。早期的研究数 据表明,罐头食品中需要含有的牛磺酸量应高于干性饲粮以保持血浆中正常的牛磺酸浓度(Pion等,1989年)。

 

Approach
方法

WALTHAM® investigated the taurine requirement of the cat by feeding diets containing various levels of taurine and measuring taurine status (plasma taurine concentration). The metabolism of taurine was also investigated, looking at taurine transport across the placenta.

威豪®通过向猫喂食各种牛磺酸含量的饲粮并测量其体内牛磺酸含量(血浆中牛磺酸浓度)的方式对 猫的牛磺酸需求量进行了研究。研究人员同时还研究了牛磺酸的代谢作用以及牛磺酸通过胎盘运输的方式。

 

Discovery (Taurine Requirement)
Canned cat food must contain more taurine than dry cat food
发现与结论(牛磺酸需求)
罐头猫粮中的牛磺酸含量必须高于干性猫粮。

The first study, in collaboration with the Animal Health Trust Small Animals Centre, Newmarket, investigated the adult cat’s minimum requirement for taurine using a semi-purified diet (Burger and Barnett 1982).

威豪在这一领域的首次研究系与纽马克特动物健康信托小动物中心合作进行。该研究 采用喂食半纯化粮的方式考察了成年猫对牛磺酸的最低需求量(Burger与Barnett,1982年)。

Subsequently, WALTHAM® investigated the taurine requirement of adult cats being fed canned or dry diets (Earle and Smith 1991). The results showed that to maintain normal plasma taurine levels, a canned diet must supply at least 39 mg taurine/kg body weight/day and a dry diet at least 19 mg/kg body weight/day (Figure 4) (Earle and Smith 1991). This was the first study to demonstrate the dietary taurine intake required from canned and dry diets. It is an important part of the literature on the taurine requirement of the cat, and contributes to the NRC recommendation for nutrient requirements in cats (NRC 2006).

后来,威豪®还对食用罐头与干性饲粮的成年猫的牛磺酸需求进行了研究 (Earle与 Smith ,1991年)。研究结果表明,罐头猫粮与干性猫粮的最低牛磺酸供应量必须分别达到39毫克牛磺酸/公斤体重/天和19毫克/公斤体重/天( 图4)才能够保持猫体内血浆中的牛磺酸浓度(Earle与Smith,1991年)。这是首例以确定罐头猫粮与干性猫粮应提供的牛磺酸含量为试验目标的研究。 该研究成果是关于猫的牛磺酸需求量方面的文献的重要组成部分, 也是美国国家研究委员会所给出的猫的营养素建议需求量的重要依据(美国国家研究 委员会,2006年)。

Reproduced from Earle KE, Smith PM. The effect of dietary taurine content on the plasma taurine concentration of the cat. Br J Nutr. 1991.66(2):227-235.查看
摘自:Earle KE与Smith PM的“饮食中的牛磺酸对猫的 血浆中牛磺酸浓度的影响”。选自:《英国营养学杂志》,1991年.66(2):227-235 查看

Figure 4: Taurine level required in diets of different formats to maintain the plasma taurine status of adult cats (Earle and Smith 1991)

继开展上述成年猫对牛磺酸的需求量研究之后,研究人员还进行了幼猫的牛磺酸需求 量研究。该项研究发现,小猫对罐头猫粮的牛磺酸生物利用度高于成年猫,但幼猫对罐头猫粮的牛磺酸生物利用度在差异性方面变化较大(Earle与Smith ,1994年)。

图4:< style="line- font-family: arial, helvetica, sans-serif;">保持成年猫体内血浆中牛磺酸浓度时不同形式猫粮 中应提供的牛磺酸含量(Earle与Smith,1991年)

Following on from these studies in adult cats, the taurine requirement of kittens was investigated. This study found that the bioavailability of taurine from canned food was higher for kittens than for adult cats, although they exhibited much greater variability in response (Earle and Smith 1994).

 

Discovery (Taurine Transport)
Studies of taurine transport across the placenta show that kittens obtain taurine from the queen
发现与结论(牛磺酸转运)
对牛磺酸通过胎盘的转运的相关研究结果显示,幼猫系通过胎盘从母体中吸 收牛磺酸。

In other species, the placenta provides the foetus with essential nutrients. The mechanism by which the queen supplied taurine to the kittens in utero was not known.
This work was conducted in collaboration with scientists at the University of Manchester (Champion et al. 2004; Champion et al. 2005). Taurine uptake was characterised in placental fragments obtained from queens during normal parturition. For the first time, it was shown that the cat placenta possesses amino acid transport systems that are functionally similar to the system β and system A transporters of the human placenta (Champion et al. 2004).

其他物种的母体胎盘能够向胎儿提供各种必需营养素。但关于母猫向其子宫内的胎儿 提供牛磺酸的机制仍不清楚。
该项研究系威豪与曼彻斯特大学的科学家共同合作开展(Champion等,2004年; Champion等,2005年)。通过对母猫正常分娩后的胎盘碎片的分析,研究人员对小猫在母猫体内对牛磺酸的摄取情况进行了研究。该研究第一次证明猫的 胎盘含有氨基酸运输系统,在功能上该系统与人类胎盘β系统和A系统转运蛋白相类似(Champion等,2004年)。

 

Iron - Key Message
铁-关键信息

WALTHAM® has helped to establish the iron requirement of cats by:
通过以下方式,威豪®成功地确定出猫对铁元素的需求量:

• Generating insight into the dietary iron content that supports normal growth of kittens.
• 得出了幼猫正常生长所需的饮食中铁元素量的结论

 

Background
背景

Iron is an essential nutrient that must be provided in the diet. It has multiple functions, being a constituent of haemoglobin and myoglobin as well as many enzymes (Burger 1993).

铁元素是饮食必须提供的一种必需营养素。铁元素具有多种作用,是血红蛋白、肌红 蛋白与多种酶的组成成分(Burger, 1993年)。
Iron deficiency typically manifests as anaemia (McCrown and Specht 2011), with abnormally low haemoglobin and haematocrit values reported in kittens (Chausow and Czarnecki-Maulden 1987).

根据相关报告,幼猫铁元素缺乏的通常表现包括贫血症(McCrown与Specht ,2011年) 、血红蛋白与红细胞压积值异常低下(Chausow 与Czarnecki-Maulden ,1987年)。
The amount of dietary iron needed to ensure normal iron metabolism in kittens was established using semi-purified diets (Chausow and Czarnecki-Maulden 1987). However, these diets were of high bioavailability (casein and dextrose) and were also phytate- and fibre-free (Chausow and Czarnecki-Maulden 1987); two constituents known to reduce iron bioavailability in other species (Lopez and Martos 2004).

研究人员采用喂食半纯化饲粮的方法确定出了在保持正常铁元素代谢条件下幼猫饮食 中应提供的铁元素量(Chausow 与Czarnecki-Maulden ,1987年)。但是,试验所采用的半纯化饲粮均具有较高的生物利用度(酪蛋白与右旋糖),并且不 含有己醇六磷酸和纤维(Chausow与Czarnecki-Maulden,1987年);饲粮中还含有两种已知能够降低其他物种体内铁元素生物利用度的成分(Lopez与Martos , 2004年)。

 

Why WALTHAM® is Interested
为何威豪®有兴趣从事该领域的研究

The iron requirement of kittens was established using semi-purified diets (with high bioavailability). However, when fed commercially available prepared petfoods the iron requirements of kittens were not known.

研究人员采用喂食半纯化饲粮(生物利用度高)的方法确定了幼猫的铁元素需求量。 但是,被喂食商业预制猫粮的小猫对铁元素的需求量仍不清楚。

 

Approach
方法

The health, growth, and development of kittens were monitored when fed standard commercial diets to confirm that the iron content was adequate.

为了确定为幼猫饲粮中的铁元素含量是否适当,研究人员对被喂食标准商业猫粮的幼 猫的健康、发育与发展情况进行了监测
Insight Generation (Iron)
Kittens consuming commercial diets with normal iron content grow and develop normally

独特见解(铁)
食用铁元素含量正常的商业饲粮的幼猫能够正常生长和发育。

In a study at WALTHAM®, two groups of 8-week-old kittens were fed for 10 weeks on nutritionally complete canned diets containing either 7.66 mg or 7.75 mg Fe/400 kcal (Harper et al. 2000). Both diets supported normal growth and development, and at the end of the study all haematological and clinical parameters were confirmed to be within the normal ranges (Harper et al. 2000). This study showed that the amount of iron present in these typical commercial diets was sufficient to support the growing kitten. These data were taken into account when formulating the NRC recommendation for iron (NRC 2006).

在威豪®进行的一项研究中,研究人员将8周大的小猫分成两组,并分别喂食营养成分完全的含铁量分别 为7.66毫克/400千卡和7.75毫克/400千卡的罐头猫粮(Harper等, 2000)。两种猫粮均能够支持小猫的正常生长与发育;在试验终点,两组小猫的全部血 液与临床参数值均处于正常范围内(Harper等,2000年)。该试验表明,上述常见商业猫粮中的铁元素含量足以支持小猫的正常发育。美国国家研究委员会 在制定铁元素建议供给量时也借鉴了上述试验数据(美国国家研究委员会, 2006)。

 

Calcium - Key Message
钙-关键信息

WALTHAM® helped establish the calcium requirement of cats by:
通过以下方式,威豪®成功地帮助研究人员确定了猫的钙需求量:

• Demonstrating that when receiving adequate dietary vitamin D, the calcium requirement of kittens is less than was thought.
• 证明在饮食中的维生素D含量适当的条件下,幼猫对钙的需求 量低于先前所知。

 

Background
背景

Calcium is an essential nutrient that must be provided in the diet. It is required for normal growth and development of the skeleton, and is mostly stored in bone. A small amount of extracellular calcium mediates functions including vasodilation, muscular contraction, and nerve transmission. The calcium concentration of plasma is kept under very tight homeostatic control, in part controlled by vitamin D which increases calcium absorption from the gut.

钙是饮食中必须含有的一种必需营养素。骨骼的正常生长与发育均需要钙;钙通常存 储于骨骼之中。少量的胞外钙具有多种介导功能,包括血管舒张、肌肉收缩与神经传递。机体通过非常严格的体内平衡控制保持血浆中的钙浓度,同时, 维生素D(能够促进机体从肠道中吸收钙)也能在一定程度上控制着体内的钙浓度。

Secondary hyperparathyroidism has been reported in cats (Krook et al. 1963; Tomsa et al. 1999), most often due to calcium deficiency caused by an all-meat diet.

在被报告的猫的继发性甲状旁腺机能亢进病例(Krook等,1963;Tomsa 等,1999年) 中,多数往往是由于进食全肉餐所引起的钙缺乏所导致。

For a long time the calcium requirement of kittens was set at 8–10 g/kg diet, based on very early calcium balance studies (see Morris et al. 1999a).

依据很早之前进行的钙平衡研究结果,很长时间以来,幼猫对钙的需求量被定为8-10 克/公斤饲粮(see Morris等,1999a)。

 

Why WALTHAM® is Interested
为何威豪®有兴趣从事该领域的研究

Because of their metabolic relationship, the adequacy of dietary calcium content can be affected by vitamin D status. Having established the vitamin D requirement of kittens (Morris et al. 1999b), the calcium requirement needed reassessing using diets containing an adequate level of vitamin D.

由于钙与维生素D之间存在代谢关系,因此饮食中的钙含量是否适当要受到维生素D的 影响。在确定出幼猫对维生素D的需求量之后(Morris 等,1999b),研究人员需要采用维生素D含量适当的饲粮对幼猫的钙需求量进行重新评估。

 

Approach
方法

The health, growth, and development of kittens were monitored when fed diets containing varying levels of calcium and a level of vitamin D confirmed to be adequate.

研究人员对被喂食钙含量不同且维生素D含量适当的饲粮的幼猫的健康、生长与发育 状况进行了监测。

 

Discovery (Calcium)
When receiving adequate vitamin D, the calcium requirement of growing kittens is less than was thought
发现与结论(钙)
在维生素D摄取量适当的条件下,发 育期幼猫对钙的需求量低于先前预期

This work was conducted in collaboration with Dr James G Morris, of the University of California, Davis.

该项研究系威豪®与加州大学戴维斯分校的James G Morris博士合作开展。

Kittens were fed a range of test diets from 9–18 weeks of age and their calcium status monitored by blood samples and dual-energy X-ray absorptiometry (Morris et al. 1999a). The five diets had a calcium:phosphorus ratio of 1:1.25 and 3.125 μg of cholecalciferol/kg, with calcium levels ranging from 3.8–8.1 g calcium/kg diet and a metabolisable energy content of about 20 kJ/g. Growth rate, energy intake, and plasma total calcium was normal on all these diets, with no clinical signs of calcium deficiency (Morris et al. 1999a). However, kittens on the lowest calcium diet had a lower bone mineral content than the others, showing that this level of calcium (3.8 g/kg diet) was suboptimal (Morris et al. 1999a). Other studies with 6 g calcium/kg diet showed that although a calcium:phosphorus ratio of 1:1.55 was adequate, an inverse ratio of 1:2.61 affected calcium and phosphorus metabolism (Morris et al. 1999a).

在试验中,研究人员向9-18个月大的幼猫喂食各种试验猫粮,并通过检测血样与双能 X线吸收测量法对其体内的钙含量进行监测(Morris等,1999a)。试验所采用的5种猫粮的钙磷比率均为1:1.25,其中的维生素D3含量为3.125微克/公斤, 含钙量范围为3.8–8.1克/公斤饲粮,代谢能含量约为20千焦/克。喂食上述饲粮的幼猫在生长率、能量摄取与血钙总浓度方面均表现正常,也并未 表现出临床缺钙的症状(Morris等, 1999a)。但被喂食钙含量最低的猫粮的幼猫的骨矿物质含量低于被喂食其他饲粮的幼猫,从而表明该种钙含量的饲粮 (3.8克/公斤饲粮)无法支持幼猫生长状况达到最佳标准(Morris 等,1999a)。采用钙含量为6克/公斤的猫粮的多项研究结果均表明,尽管1:1.55的钙磷 比被证明具有适当性,但达到1:2.61的钙磷比却对钙磷的代谢构成不良影响(Morris 等,1999a)。

This study concluded that the calcium requirement of kittens was no more than 6 g/kg diet – much less than previously thought to be required (Morris et al. 1999a) – and these data were subsequently taken into account when formulating the NRC recommendation for calcium (NRC 2006).

该项研究得出的结论是:幼猫对钙的需求量不超过6克/公斤饲粮——这一 数值远远低于人们先前的预期(Morris等,1999a)——后来,美国国家研究委员会在制定钙供给量建议值时也参考了上述数据(美国国家研究委 员会, 2006年)。

 

Vitamin D - Key Message
维生素D-关键信息

WALTHAM® helped establish the vitamin D requirement of cats by:
威豪®通过以下方式帮助研究人员确定了猫对维生素D的需求量:
• Demonstrating the dietary vitamin D content that meets the needs for growth of kittens.
• 证明了满足幼猫生长需要所需的猫粮中维生素D含量。

 

Background
背景

The main function of vitamin D is to increase calcium and phosphorus absorption from the gut, and mobilise calcium from bone.

维生素D的主要功能是提高机体从肠道中对钙与磷的吸收并促进骨骼的钙化。
Most animals can synthesise vitamin D in the skin. However, vitamin D synthesis by growing kittens exposed to ultraviolet light is ineffective (Morris 1999). This means they need a dietary source of vitamin D, which is ordinarily provided in the wild by prey items (Morris 1999).

多数动物均能够通过皮肤合成维生素D。但发育期幼猫即使采用紫外线照射的方式也 无法合成维生素D(Morris ,1999年)。这表明,幼猫需要从猫粮中获取维生素D源(在野生条件下,猫通过捕获猎物获得维生素D源)(Morris ,1999年) 。

Vitamin D deficiency classically causes rickets, and has been previously reported in cats (Gershoff et al. 1957).

维生素D缺乏通常会导致佝偻病;猫因缺乏维生素D所导致的佝偻病此前已有报道 (Gershoff等,1957年)。
The vitamin D requirement of kittens was established in very early studies (Gershoff et al. 1957). However, these data are questionable due to the high mortality rate (Morris et al. 1999).

较早期的研究已经确定了幼猫对维生素D的需求量(Gershoff等,1957年)。但由于该 需求量会导致较高的死亡率,因此该试验数据的有效性仍然值得怀疑(Morris ,1999年)。

 

Why WALTHAM® is Interested
为何威豪®有兴趣从事该领域的研究

Vitamin D is an essential nutrient for kittens, and it is important to understand how much they need in order to provide food that supports growth and healthy development.

维生素D是幼猫的必需营养素。确定出幼猫对维生素D的需求量有助于为其提供能够支 持其生长与健康发育的饲粮,因此具有重要意义。

 

Approach
方法

The amount of dietary vitamin D (as cholecalciferol) necessary to maintain adequate plasma levels of 25-hydroxyvitamin D (25-OHD) was investigated.

研究人员以保持血浆中25-羟基维生素D的适当浓度为标准对饮食中应提供维生素D( 维生素D3)含量进行了研究。

 

Discovery (Vitamin D)
The vitamin D requirement of growing kittens is less than was thought
发现与结论(维生素D)
发育期幼猫的维生素D需求量低于人 们先前的预期。

This work was conducted in collaboration with Dr James G Morris, of the University of California, Davis.

该项研究系威豪®与加州大学戴维斯分校的James G Morris博士共同开展。

Kittens aged 9 weeks were fed diets (20 kJ/g metabolisable energy) containing 12 g calcium and 8 g phosphorus, and 0–25 μg of cholecalciferol/kg diet (Morris et al. 1999). There were no adverse clinical effects nor radiographic abnormalities observed at 22 or 34 weeks of age (Morris et al. 1999). Plasma concentrations of 25-OHD were highly correlated with dietary cholecalciferol (Morris et al. 1999). At 22 weeks of age, the kittens fed 6.25 μg cholecalciferol/kg diet had plasma 25-OHD concentrations greater than 50 nmol/L – the level which is considered replete for humans – and this was identified as the vitamin D requirement for kittens (Morris et al. 1999).

在试验中,研究人员向9周大的幼猫喂食钙、磷与维生素D3含量分别为12克/公斤、8 克/公斤与0–25微克/公斤的猫粮(代谢能为20千焦/克)(Morris 等,1999年)。在幼猫22周和33周大时,研究人员未观察到幼猫出现任何临床不良 反应,幼猫的放射学检查结果也未见异常(Morris 等,1999年)。血浆中的25-羟基维生素D浓度与幼猫饮食中的维生素D3含量存在高度相关性(Morris 等 ,1999年)。在22周大时,被喂食维生素D3含量为6.25微克/公斤的饲粮的幼猫的血浆中的25-羟基维生素D浓度超过50纳摩/升(这一浓度被视为人的充分 浓度),研究人员即以该维生素D3含量作为幼猫的维生素D需求量(Morris ,1999年)。

This study showed that the vitamin D requirement of kittens was much less than previously thought (Morris et al. 1999), and these data were subsequently taken into account when formulating the NRC recommendation (NRC 2006).

该项研究表明,幼猫的维生素D需求量低于人们先前的预期值(Morris ,1999年);美 国国家研究委员会在制定维生素D建议供给量时也参考了上述试验数据。

本文为玛氏宠物护理学院原创内容,转载请注明出处。