The authors wish to acknowledge funding from UL1TR000071 (NCATS), P30DK079638 (NIDDK), P30DA028821 (NIDA) and T32DA07287 (NIDA).

All experimental procedures are in accordance with the Guide for the Care and Use of Laboratory Animals (Institute of Laboratory Animal Resources (U.S.), 1996) and with the approval of the Institutional Animal Care and Use Committee at the University of Texas Medical Branch.
1. Subjects
<ol>
	<li>Single house male Sprague-Dawley rats weighing 225-250 g at 21 &#176;C and 30-50% relative humidity with a 12 hr light-dark cycle (lights on 6:00 am-6:00 pm).</li>
	<li>Maintain rats on a low fat fo...

<ol>
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The authors have nothing to disclose.

The Fat Preference model is an informative and easy to perform assay of feeding behavior. This assay offers an opportunity to identify neural and molecular mechanisms which underlie food preference, which is an important yet understudied area of obesity research. Changes in fat preference from genetic differences or pharmacological manipulations could be visualized as rightward or leftward shifts in the preference curve (Figure 3B). It is important to include the middle fat foods (15%, 17.5%, and 20%) to...

Obesity is a prevalent problem in the United States1, with the Centers for Disease Control and Prevention estimating that over a third of American adults are obese. Obesity has also been identified as a risk factor for numerous health concerns, including type 2 diabetes, high blood pressure, and high cholesterol2. While many factors have been shown to influence the increase in obesity rates, there is ongoing interest and controversy in the role macronutrients play in obesity3,4.
One contributing factor to obesity is high dietary fat intake5. Increased dietary fat is correlated with increased human energy consumption6 and significant increases in body fat content7,8. Additionally, dietary fat has reward value both during and after consumption7,9. Therefore, determining what factors influence preference for high fat foods can both guide pharmacotherapeutic design and promote understanding of the underlying dietary choices that can lead to obesity. The Fat Preference model described here tests for rats&#8217; preference between foods of differing fat content, but similar nutritional value. Specifically, this model presents the rats with a choice of two different foods simultaneously thus enabling the quantification of preference based on grams consumed of the lower fat food verses the higher fat food. Pharmacological and genetic effects can be measured as a change in preference for the food with higher fat content.
The Fat Preference model serves to complement the widely used palatable food intake models10 but also offers several advantages. This model allows the experimenter to specifically assess feeding behavior in a controlled environment in which two food options are available. Traditional high fat feeding models only offer one food which eliminates the capacity to study food choice, an important aspect of human food intake. Some assays do offer multiple food types and are often referred to as &#34;cafeteria&#34; type feeding studies11. These studies suffer from reproducibility because human food is often used in the assay and is not well suited to the laboratory environment due to nutrient variability. We use defined diets which contain individual purified ingredients thus greatly improving reproducibility and flexibility to change macronutrient content such as dietary fat. With higher dietary fat intake associated with obesity in humans5 and the natural human preference for higher fat foods12, treatments that alter rat preference for high fat foods can provide valuable insight into obesity.

<table border="0" cellpadding="0" cellspacing="0" width="673">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">&#160;Rodent diet with 10 kcal% fat&#160;</td>
			<td style="width:111px;">Research Diets</td>
			<td style="width:119px;">D12450B</td>
			<td style="width:167px;">10 % fat rat food</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">&#160;Rodent diet with 12.5 kcal% fat&#160;</td>
			<td style="width:111px;">Research Diets</td>
			<td style="width:119px;">D07040501</td>
			<td>12.5 % fat rat food</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">&#160;Rodent diet with 15 kcal% fat&#160;</td>
			<td style="width:111px;">Research Diets</td>
			<td style="width:119px;">D07040502</td>
			<td>15 % fat rat food</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">&#160;Rodent diet with 17.5 kcal% fat&#160;</td>
			<td style="width:111px;">Research Diets</td>
			<td style="width:119px;">D07040503</td>
			<td>17.5 % fat rat food</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">&#160;Rodent diet with 20 kcal% fat&#160;</td>
			<td style="width:111px;">Research Diets</td>
			<td style="width:119px;">D07040504</td>
			<td>20 % fat rat food</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">&#160;Rodent diet with 45 kcal% fat&#160;</td>
			<td style="width:111px;">Research Diets</td>
			<td style="width:119px;">D12451</td>
			<td>45 % fat rat food</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:277px;">Rat feeders (3.75&#34;W x 2.875&#34;D x 5.25&#34;H)</td>
			<td style="width:111px;">Labex of MA</td>
			<td style="width:119px;">2528</td>
			<td>Food hoppers</td>
		</tr>
	</tbody>
</table>

fat preference: a novel model of eating behavior in rats

Obesity is a growing problem in the United States of America, with more than a third of the population classified as obese. One factor contributing to this multifactorial disorder is the consumption of a high fat diet, a behavior that has been shown to increase both caloric intake and body fat content. However, the elements regulating preference for high fat food over other foods remain understudied.
To overcome this deficit, a model to quickly and easily test changes in the preference for dietary fat was developed. The Fat Preference model presents rats with a series of choices between foods with differing fat content. Like humans, rats have a natural bias toward consuming high fat food, making the rat model ideal for translational studies. Changes in preference can be ascribed to the effect of either genetic differences or pharmacological interventions. This model allows for the exploration of determinates of fat preference and screening pharmacotherapeutic agents that influence acquisition of obesity.

Rats had physical access to both food hoppers simultaneously (Figure 1) in order to demonstrate preference for available food choices with differing fat content (Table 1). Rat food was weighed daily and any food spillage was easily found and accounted for (Figure 2). Spillage of fine food particles was found to be minimal and does not substantially influence the data. Using the Fat Preference model, a clear preference between foods containing 12.5% fat and higher fat foo...

Watch this Scientific Journal Video about Fat Preference: A Novel Model of Eating Behavior in Rats at JoVE.com

Fat Preference: A Novel Model of Eating Behavior in Rats

Dietary fat content influences both energy intake and body fat composition in mammals. By examining rats&#8217; preference for high fat food in a series of choice experiments, it is possible to test genetic differences and pharmacological interventions on their preference for high fat food.

Obesity is a growing problem in the United States of America, with more than a third of the population classified as obese. One factor contributing to ...

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13.0K Views.  University of Texas Medical Branch.  Influenze tenore di grassi alimentari, sia l'apporto energetico e composizione corporea grasso nei mammiferi. Esaminando la preferenza ratti di cibo ricco di grassi in una serie di esperimenti di scelta, è possibile testare le differenze genetiche e interventi farmacologici sulla loro preferenza per il cibo ricco di grassi. 