Regulation of lipid metabolism by dietary sorbose in laying hens

Rare mono- and disaccharides as healthy alternative for traditional sugars and sweeteners?

Obesity and type 2 diabetes are major health problems affecting hundreds of millions of people. Caloric overfeeding with calorie-dense food ingredients like sugars may contribute to these chronic diseases. Sugar research has also identified mechanisms via which conventional sugars like sucrose and fructose can adversely influence metabolic health. To replace these sugars, numerous sugar replacers including artificial sweeteners and sugar alcohols have been developed. Rare sugars became new candidates to replace conventional sugars and their health effects are already reported in individual studies, but overviews and critical appraisals of their health effects are missing. This is the first paper to provide a detailed review of the metabolic health effects of rare sugars as a group. Especially allulose has a wide range of health effects. Tagatose and isomaltulose have several health effects as well, while other rare sugars mainly provide health benefits in mechanistic studies. Hardly any health claims have been approved for rare sugars due to a lack of evidence from human trials. Human trials with direct measures for disease risk factors are needed to allow a final appraisal of promising rare sugars. Mechanistic cell culture studies and animal models are required to enlarge our knowledge on understudied rare sugars.

Changes in gonadal weights, serum lipids, and glucose during maturation in the juvenile northern bobwhite quail (Colinus virginianus)

Changes in serum lipids, serum glucose, and gonadal development during maturation of Colinus virginianus were determined in two trials. In Trial 1, sex, BW, and serum concentrations of total cholesterol, high, low, and very low density lipoprotein cholesterol, triglycerides, and glucose were determined every 2 d from 2 to 14 d and weekly from 21 to 49 d. Relative ovary or testis weights between 14 and 49 d were determined weekly. Body weight increased and all measured serum constituents changed in males and females between 2 and 49 d; however, relative testis weight decreased between 14 and 49 d. In Trial 2, sex, BW, cholesterol, and relative ovary and testis weights were determined in birds at 56 and 63 d of age. The distinctness of external sexual phenotype and its relationship to BW, cholesterol, and relative gonadal weight were also determined at 56 and 63 d. Body weight increased and serum cholesterol decreased in both sexes between 56 and 63 d, but had no association with the distinctness of external sexual phenotype. It was concluded that the development of external sexual identity in male and female Northern Bobwhite quail prior to sexual maturity was not related to changes in BW, gonad weight, serum lipids, or serum glucose before 63 d of age.

Reduced plasma cholesterol and lipoprotein in laying hens without concomitant reduction of egg cholesterol in response to dietary sorbose

Experiments were conducted to determine the effect of sorbose on feed consumption, egg production and size, and cholesterol metabolism of laying hens. In Experiment 1, 87-wk-old laying hens (10 per treatment) were fed diets containing 0, 10, or 20% sorbose for 4 wk. In a second experiment, 108-wk-old laying hens (eight per treatment) were fed a control diet, a diet with 10% added sorbose, or the control diet with intake restricted to the level of sorbose-treated hens for 4 wk. Feed consumption and egg production were recorded daily. Plasma and egg cholesterol levels were determined at 0, 2, and 4 wk. Plasma and egg very low density lipoprotein (VLDL) concentrations were determined after 4 wk. Egg production, feed intake, and body weight gain were significantly reduced by dietary sorbose. Egg and yolk weight and percentage yolk decreased in response to sorbose. Sorbose significantly reduced plasma cholesterol and VLDL by approximately 50%, compared with the hens fed a control diet. Egg cholesterol concentration (milligrams per gram of yolk) was significantly increased, although the reduction in yolk size resulted in similar total egg cholesterol (milligrams per egg). Restricting feed intake of laying hens significantly lowered plasma cholesterol, but not to levels comparable to that of sorbose-treated hens. The data indicate that substantial reduction of plasma cholesterol and VLDL by dietary sorbose was not accompanied by reduced egg cholesterol.

Influence of dietary sorbose on lipogenesis in gold thioglucose-injected obese mice

1. The influence of dietary sorbose on food intake and fatty acid synthesis of the liver and epididymal white adipose tissue (EWAT) was investigated in gold thioglucose (GTG)-injected obese mice from 12 to 14 weeks of age. 2. Sorbose was supplemented to a semi-purified diet at a level of 200 g/kg diet at the expense of sucrose. 3. On the last day of the experiment, fatty acids synthesis in the liver and EWAT was measured using an i.p. injection [1-14C]sodium acetate. 4. The decreases in body weight and food intake by dietary sorbose in GTG-injected obese mice were greater than those in control mice. 5. Lipid content and fatty acid synthesis in the liver and EWAT of control mice were not influenced by dietary sorbose. 6. In GTG-injected obese mice, the reduction of food intake by dietary sorbose suppressed fatty acid synthesis and lipid deposition in both liver and EWAT.

Effect of gamma-linolenic acid on lipid metabolism in laying hens

1. Single comb white leghorn laying hens were given diets with additional mould, Mucus circineloides, containing gamma-linolenic acid (GLA) at levels of 0, 2.59 and 5.06 g GLA/kg diet ad lib. for 2 weeks and serum lipid contents were determined in experiment 1. 2. Serum low density lipoprotein and chylomicron levels were significantly reduced with the increase of dietary GLA levels. Serum triglyceride and cholesterol tended to be lowered by dietary GLA, but not significantly different. 3. Effects of mould GLA and extracted oil GLA on the egg yolk cholesterol concentration and fatty acid composition were compared in experiment 2. Both mould GLA and extracted oil GLA diets containing 5.32 and 4.71 g GLA/kg diet were given ad lib. for 2 weeks. 4. Yolk cholesterol content was not affected by dietary GLA sources. Content of GLA in the yolk was not altered, although that of arachidonic acid was enhanced by dietary GLA supplementation, particularly by the extracted oil GLA. 5. It is suggested that GLA is rapidly metabolized to arachidonic acid in the body and incorporated into the yolk.

Effect of dietary sorbitol on the performance of broilers

1. The effect of dietary sorbitol on the performance of broilers was investigated. Male and female broilers were given a control diet or a sorbitol diet (100 g/kg diet) ad libitum from 29 to 57 d of age. 2. Body weight gain, food intake, food efficiency and the ME values of the diets were not significantly different. Absolute and relative weights of abdominal fat were significantly reduced in birds given the sorbitol diet. 3. Compared to the control diet, the diet containing sorbitol lowered the serum glucose, total cholesterol and very low density lipoprotein concentrations.

Energy utilisation in germ-free and conventional chicks fed diets containing sorbose

1. In experiment 1, growing conventional (CV) chicks were fed on diets containing graded amounts (0, 100, 200 and 300 g/kg diet) of sorbose from 4 to 14 d. Protein, fat and energy deposition were determined after carcase analysis. The values for growth, food efficiency, metabolisable energy (ME) and fat and energy depositions declined as the dietary sorbose content increased. 2. In experiment 2, the performances of germ-free (GF) and CV chicks fed on diets with (100 g sorbose/kg diet) or without sorbose were investigated. On both diets, body weight gain, food consumption and protein accumulation in GF chicks were significantly higher than those in CV birds. No significant differences were observed between the dietary treatment except for ME values, which were significantly lower for the sorbose diet. 3. It is suggested that dietary sorbose decreased energy utilisation, and that the microbial contribution to the utilisation of dietary sorbose was negligible in the chicken.

Effect of dietary sorbose on lipid metabolism in male and female broilers

Male and female broilers were given diets (6 males and 6 females per diet) containing varying percentages of sorbose (0, 3, 6, and 9%) and fed for ad libitum access from 28 to 56 days of age. Body weight gain and feed intake were decreased with increasing dietary sorbose, particularly in male birds fed diets containing 9% sorbose, although feed efficiency and N retention rate were not influenced by dietary treatments. Absolute and relative abdominal fat weights were higher in females than in males and decreased with the increasing levels of dietary sorbose in both sexes. Fat content in the pectoral muscle also decreased as dietary sorbose increased. Dietary sorbose did not have significant effects on serum glucose, triglyceride, total cholesterol, low density lipoprotein, very low density lipoprotein, and chylomicron levels in either male or female birds. The ME values of diets decreased as dietary sorbose increased. Palmitic acid content of abdominal fat was significantly lower in birds fed the 9% sorbose diet than in birds fed the control diet. The reverse was true for linoleic acid content. It was concluded that dietary sorbose can be used as a potential regulator of lipid deposition in broilers.