Effect of a Lard Diet and Fish Oil Diet during the Growth Period on Preferential Fat Intake in Adult Rats

Sato

Saito

2009

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Summary These studies aimed to compare the effects of ␣ -linolenic acid (ALA) ϩ eicosapentaenoic acid (EPA) ϩ docosahexaenoic acid (DHA) on plasma-lipid concentrations and preferential fat intake of rats fed a lard diet (LD). Each of 2 groups of 4-wk-old male rats was used in studies 1 and 2. In studies 1 and 2, two groups of rats received the LD (LD group) and the fish-oil diet (FD; FD group), and the LD and the perilla-oil diet (PD; PD group), respectively (dietary treatment period). After 6 wk, 6 rats per group were sacrificed. The remaining rats in studies 1 and 2 were placed on a self-selection regimen of the LD and the FD, and the LD and the PD, respectively, for 3 wk (self-selection period). After the dietary treatment period, plasma lipid concentrations in the FD group were lower than those in the LD group. However, no significant difference in the concentrations was observed between the LD group and the PD group. At the beginning of the self-selection period, the ratio of the FD intake of the LD group was higher than that of the FD group. As the the ratio of the LD group decreased and that of the FD group increased no significant difference in the ratio was observed after the 9th day during the self-selection period. No significant difference in the ratio of the PD intake was observed between the LD group and the PD group during the selfselection period. Thus, although the FD decreased plasma lipid concentration and increased the preferential FD intake of the LD group at the beginning of the self-selection period, the PD did not. Our studies clearly show that dietary EPA ϩ DHA and ALA have different physiologic effects.

Section: Discussionmentioning

confidence: 99%

Effect of Plant- and Fish-Oil Derived n-3 Polyunsaturated Fatty Acids on Counteraction of n-3 Fatty Acid Shortage in Adult Rats Fed a Lard Diet

Sato

Saito

2009

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“…It appears that the odor or the flavor associated with a mother's diet is transmitted via her milk to nursing pups, and that these cues influence pups' initial choice of diet ( 4 -7 ). The large variations that exist in food choice, especially for fat preference, can be linked to animal strain, age, environment, genetic background or prenatal nutrition, diet history, and modifications of energy expenditure such as exercise and food deprivation (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Although determinations of food choice are still a matter of conjecture, it is likely that rats select macronutrients according to their need and in order to achieve optimal adaptation ( 9 ).…”

Section: Discussionmentioning

confidence: 99%

Preferential Fat Intake of Pups Nursed by Dams Fed Low Fat Diet during Pregnancy and Lactation Is Higher than That of Pups Nursed by Dams Fed Control Diet and High Fat Diet

Tsukita

Yokoyama

2008

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SummaryTo investigate the effect of dams' dietary fat type during pregnancy and lactation on fat choice of pups, three groups of dams were fed one of three diets: a low fat diet (LFD), a control diet (CTD) or a high fat diet (HFD). After weaning their pups were offered a self-selection regimen of both a fat protein diet (FPD) and a carbohydrate protein diet (CPD) for 3 wk. Although the ratio of FPD intake [FPD intake (g)/total intake (g)] by pups nursed by dams fed LFD during the self-selection period was higher than that by pups nursed by dams fed CTD and HFD, no significant difference in the ratio was observed between pups nursed by dams fed CTD and HFD. It was considered that pups nursed by dams fed CTD and HFD self-selected FPD and CPD in an adequate fat energy ratio (F ratio) compared to that of AIN-93G and AIN-93M. The ratio of FPD intake by pups of these three groups was 16-21% within the first week after weaning. Although pups nursed by dams fed CTD continued to consume the same ratio of FPD during the self-selection period, the ratio of pups nursed by dams fed LFD increased and that of pups nursed by dams fed HFD decreased. These findings indicate that: [1] pups nursed by dams fed CTD and HFD have the ability to consume FPD and CPD in an adequate F ratio, and [2] preferential fat intake of pups nursed by dams fed LFD is stronger than that of pups nursed by dams fed CTD and HFD. Key Words prenatal nutrition, dietary self-selection, fat preference, weaning pup Recently, young people in Japan prefer a Westernstyle diet, and now more than 25% of the energy consumed by young people is provided by fat ( 1 ). Specifically, animal products such as meat, fish, milk, milk products, and eggs contribute about half of the total fat in Japanese diets. Although the physiological factors contributing to fat diet selection are unknown, it is clear that greater consumption of fat is associated with higher caloric intake as well as increased body weight and adipose tissue depositions ( 2 ). The risk and incidence of obesity, type-2 diabetes, atherosclerotic vascular disease and coronary heart disease are increasing in rapid proportion to the increased intake of animal fat intake ( 3 ).Triacylglycerols are the principal lipid component of food and can enhance palatability by absorbing and retaining flavors and by influencing the texture of foods. Some empirical studies have shown that weaning pups are strongly influenced in their initial choice of diet by dietary preferences learned from adult rats. It appears that the odor or the flavor associated with a mother's diet is transmitted via her milk to nursing pups, and that these cues influence pups' initial choice of diet ( 4 -7 ). The large variations that exist in food choice, especially for fat preference, can be linked to animal strain, age, environment, genetic background or prenatal nutrition, diet history, and modifications of energy expenditure such as exercise and food deprivation (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Although dete...

“…In addition, the fish-oil HFD guarded against the overeating of fats ( 10 ). Although fish-oil is nutritionally less desirable than lard and soybean-oil, when rats were placed on a self-selection regimen of a lard diet and a fish-oil diet they had the ability to consume both diets to obtain an adequate ratio of essential fatty acids ( 11,12 ).…”

mentioning

confidence: 99%

Zinc's Role in Rat Preference for a Low-Fat Diet in a Two-Choice Diet Program of Low- and High-Fat Diets

2011

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SummaryTo investigate the change in preference for a low-fat diet (LFD) and a high-fat diet (HFD) under disorders induced by a zinc (Zn)-deficiency, two groups of 4-wk-old male rats were fed a two-choice diet of Zn-deficient (ZnD; 0.75 mg/kg) and Zn-adequate (ZnA; 30.75 mg/kg) LFD and HFD. After 21 d, 10 rats in each of the two groups were sacrificed. The remaining ZnD rats were switched to ZnA diets for 7 d. Intakes of the LFD and the HFD were measured to determine the diet preferences of the ZnD, the ZnA and the Zn-recovered groups. Energy intake of the ZnD group was significantly lower than that of the ZnA group and showed cyclical 3-to 4-d patterns of decrease. In the ZnD group, although the LFD intake decreased parallel to the reduction in the energy intake, the HFD intake did not show the cyclical pattern of decrease. The reduced intake of the LFD in the ZnD rats was accompanied by a low carbohydrate intake and a low plasma insulin concentration. When the ZnD group recovered sufficient amounts of Zn, the energy intake was restored to normal levels and the difference in the LFD intake and the plasma insulin concentration disappeared between the ZnD and the ZnA groups. It was supposed that the specific change in the LFD intake patterns during development and recovery from Zn-deficiency might be related to Znmediated changes in impaired synthesis and the release of insulin from the pancreas. Key Words zinc-deficiency, self-selection, preference for a low-fat diet, two-choice diet program, high-fat diet Zinc (Zn) is essential for animals and humans, and is required for many physiological functions. A Zn-deficiency in both animals and humans causes anorexia, a taste disorder, a poor appetite, impaired growth and dermatitis ( 1-3 ). Within 3 to 5 d after giving rats a Zndeficient (ZnD) diet, food intake is suppressed ( 3,4 ). This decrease in food intake is the first sign of Zn-deficiency, followed by other symptoms associated with Zndeficiency ( 3 ). Therefore, Zn may play an important role in the regulation of food intake.From a whole-body perspective, ZnD rats have significantly reduced body weight and carcass fat, and lower circulating leptin and insulin concentrations that play key roles in energy nutrient metabolism compared to the Zn-adequate (ZnA) rats ( 4-7 ). Leptin is produced by adipose tissue and has potent effects on body weight and food intake regulation. Another adiposity signal is insulin, which is the controller of blood glucose levels, and chronically high levels of insulin consequently lead to obesity ( 8 ). Arora and Anubhuti reported that leptin and insulin are ideal candidates for lipogenic function because their levels are closely related to adiposity, and their central administration decreases food intake ( 9 ). However, feeding is a complex behavior and the mechanisms by which Zn-deficiency induces anorexia are unclear. Zn-deficiency results in a reduction of food intake, suggesting that Zn status may affect the complex mechanisms underlying normal food intake.In a previous paper, we re...