Intestinal Permeability Measured by Urinary Sucrose Excretion Correlates with Serum Zonulin and Faecal Calprotectin Concentrations in UC Patients in Remission.

BACKGROUND AND AIMS: Ulcerative colitis (UC) is associated with an increased intestinal permeability, possibly through a dysbiosis of intestinal bacteria. We investigated which markers are most relevant to assess intestinal permeability in UC patients and whether probiotics had an effect on these markers. METHODS: In this twelve-week placebo-controlled randomized double-blind study, twenty-five subjects with UC in remission received either placebo or a multispecies probiotics. Samples of blood, urine, and faeces were taken at baseline, week 6, and week 12 to assess intestinal permeability and inflammation. Diaries and Bristol stool scale were kept to record stool frequency and consistency. Quality of life was scored from 32-224 with the inflammatory bowel disease questionnaire (IBD-Q). RESULTS: This group of UC patients, in clinical remission, did not show increased intestinal permeability at baseline of this study. During the study, no significant group or time effects were found for intestinal permeability measured by the 5-sugar absorption test, serum zonulin, and faecal zonulin. Likewise, the inflammatory markers C-reactive protein (CRP), calprotectin, and the cytokines IFNγ, TNFα, IL-6, and IL-10 were not significantly affected. Stool frequency and consistency were not significantly affected either. The IBD-Q score, 194 for the probiotics group and 195 for the placebo group, remained unaffected. Correlations were tested between all outcomes; urinary sucrose excretion was significantly correlated with serum zonulin (r = 0.62) and faecal calprotectin (r = 0.55). Faecal zonulin was not significantly correlated with any of the other markers. CONCLUSION: Serum zonulin may be a more relevant biomarker of intestinal permeability than faecal zonulin, due to its correlation with other biomarkers of intestinal permeability. UC patients in remission did not show an effect of the probiotic treatment or a change in gut permeability. This should not discourage further studies because effects might be present during active disease or shortly after a flare up.

Effects of chemically or technologically treated linseed products and docosahexaenoic acid addition to linseed oil on biohydrogenation of C18:3n-3 in vitro.

Rumen biohydrogenation kinetics of C18:3n-3 from several chemically or technologically treated linseed products and docosahexaenoic acid (DHA; C22:6n-3) addition to linseed oil were evaluated in vitro. Linseed products evaluated were linseed oil, crushed linseed, formaldehyde treated crushed linseed, sodium hydroxide/formaldehyde treated crushed linseed, extruded whole linseed (2 processing variants), extruded crushed linseed (2 processing variants), micronized crushed linseed, commercially available extruded linseed, lipid encapsulated linseed oil, and DHA addition to linseed oil. Each product was incubated with rumen liquid using equal amounts of supplemented C18:3n-3 and fermentable substrate (freeze-dried total mixed ration) for 0, 0.5, 1, 2, 4, 6, 12, and 24h using a batch culture technique. Disappearance of C18:3n-3 was measured to estimate the fractional biohydrogenation rate and lag time according to an exponential model and to calculate effective biohydrogenation of C18:3n-3, assuming a fractional passage rate of 0.060/h. Treatments showed no differences in rumen fermentation parameters, including gas production rate and volatile fatty acid concentration. Technological pretreatment (crushing) followed by chemical treatment applied as formaldehyde of linseed resulted in effective protection of C18:3n-3 against biohydrogenation. Additional chemical pretreatment (sodium hydroxide) before applying formaldehyde treatment did not further improve the effectiveness of protection. Extrusion of whole linseed compared with extrusion of crushed linseed was effective in reducing C18:3n-3 biohydrogenation, whereas the processing variants were not different in C18:3n-3 biohydrogenation. Crushed linseed, micronized crushed linseed, lipid encapsulated linseed oil, and DHA addition to linseed oil did not reduce C18:3n-3 biohydrogenation. Compared with the other treatments, docosahexaenoic acid addition to linseed oil resulted in a comparable trans11,cis15-C18:2 biohydrogenation but a lesser trans10+11-C18:1 biohydrogenation. This suggests that addition of DHA in combination with linseed oil was effective only in inhibiting the last step of biohydrogenation from trans10+11-C18:1 to C18:0.

Effect of dietary fat sources on fatty acid deposition and lipid metabolism in broiler chickens.

The hypothesis tested was that dietary vegetable fats rich in saturated fatty acids, when compared with a vegetable oil rich in linoleic acid, increase fat deposition in broiler chickens and affect synthesis or oxidation, or both, of individual fatty acids. Diets with native sunflower oil (SO), a 50:50 mix of hydrogenated and native SO, palm oil, and randomized palm oil were fed to broiler chickens. Intake of digestible fat and fatty acids, whole body fatty acid deposition, hepatic fatty acid profile, and hepatic enzyme activities involved in fatty acid oxidation and synthesis were measured. The fat deposition:digestible fat intake ratio was significantly lower for the SO group in comparison with the groups fed the vegetable fats rich in saturated fatty acids. The difference between digestible intake and deposition of C18:2, reflecting its maximum disappearance rate, was highest for the SO group and lowest for the palm oil- and randomized palm oil-fed birds. The calculated minimal rate of de novo synthesis of monounsaturated fatty acids (MUFA), calculated as deposition minus digestible intake, was more than 50% lower for the SO group than for the other 3 dietary groups. Based on the fatty acid profiles in the liver, it would appear that increasing contents of C18:2 decrease the desaturation of saturated fatty acids into MUFA. It is concluded that a diet rich in C18:2 in comparison with different kinds of vegetable saturated fatty acids decreases the deposition of fat, especially of MUFA. It appears to be caused by a higher ß-oxidation and a reduced de novo synthesis of MUFA, but this conclusion is not fully supported by the measured activities of enzymes involved in fatty acid synthesis and oxidation.

Digestion and deposition of individual fatty acids in growing-finishing pigs fed diets containing either beef tallow or sunflower oil.

The apparent digestibility and deposition in carcass of individual dietary fatty acids (FA) were determined in growing-finishing pigs fed diets containing either beef tallow or sunflower oil. The beef tallow was rich in saturated FA (SFA) and the sunflower oil had a high content of polyunsaturated FA (PUFA). A total of 39 barrows was used. The experimental diets contained 5% (w/w) of the variable fat source and were fed ad libitum. The dietary fat type had no effect (p > 0.05) on growth performance, even though the apparent digestibilities of crude fat and crude protein were higher (p < 0.05) in the animals fed sunflower oil. The pigs fed the sunflower oil diet showed higher apparent digestibilities (p < 0.05) of the sum of SFA, monounsaturated FA (MUFA) and PUFA, but had a lower digestibility (p < 0.05) of stearic acid. The intakes of individual digestible FA were derived feed intake data, FA contents of the diets and the digestibility of individual FA. For the entire feeding period of 13 weeks, the ratio of deposition in carcass to intake of digestible FA was increased (p < 0.05) for palmitic and stearic acid in the pigs fed sunflower oil, but the ratios for oleic acid and linoleic acid were decreased (p < 0.001). In the pigs fed sunflower oil instead of beef tallow, the deposition:intake ratio was raised for the SFA (p < 0.001), but diminished for the MUFA (p < 0.05). The calculated minimum de novo synthesis of SFA was increased (p < 0.05) and that of MUFA decreased (p < 0.05) in the pigs fed sunflower oil. It is concluded that the feeding of a diet with sunflower oil instead of beef tallow improved apparent digestibility of SFA, MUFA and PUFA, increased the deposition:digestible intake ratio for SFA, but lowered that for MUFA and PUFA.

Fatty acid digestion and deposition in broiler chickens fed diets containing either native or randomized palm oil.

The hypothesis tested was that randomization of palm oil would increase its digestibility, especially that of its palmitic acid (C16:0) component, with subsequent changes in the fatty acid composition in body tissues. Broiler chickens were fed diets containing either native or randomized palm oil. Diets with either native or a 50/50 mix of native and hydrogenated sunflower oil were also fed. Randomization of palm oil raised the fraction of C16:0 at the sn-2 position of the glycerol molecule from 14 to 32%. Hydrogenation of sunflower oil reduced fat and total saturated fatty acid digestibility, whereas no change in digestibility of total unsaturated fatty acids was found. Randomization of palm oil raised the group mean apparent digestibility of C16:0 by 2.6 and 5.8% units during the starter and grower-finisher phase, respectively. On the basis of the observed digestibilities in the grower-finisher period, it was calculated that the digestibility for C16:0 at the sn-2 and sn-1,3 position was 90 and 51%, respectively. The feeding of randomized instead of native palm oil significantly raised the palmitic acid content of breast meat and abdominal fat and lowered the ratio of unsaturated to saturated fatty acids. It is concluded that randomized palm oil may be used as vegetable oil in broiler nutrition with positive effect on saturated fatty acid digestibility when compared with native palm oil and positive effect on firmness of meat when compared with vegetable oils rich in unsaturated fatty acids.

Body composition and heat expenditure in broiler chickens fed diets with or without trans fatty acids.

The effect of a diet containing trans fatty acids (TFA) on the fatty acid composition and fat accumulation was investigated in broiler chickens. Female broilers were fed a control or a TFA-containing diet. The difference between the diets was that a part of cis 18:1 in the control diet was replaced by the TFA. Body composition, energy balance and the fatty acid composition were examined. Over the time-period studied (15 days), the body fat content and the protein content did not differ significantly between the TFA-fed group and the control. In energy balance studies, total energy intake, energy loss in excreta, energy expenditure and energy storage did not differ between the treatments. Compared to the control diet, the TFA diet resulted in significantly higher amounts of 14:0 and 18:1n-7 and lower amounts of 18:1n-9 and 20:4n-6 in the body. In conclusion, the data suggest that feeding TFA for 15 days to female broilers had no effect on energy retention, energy expenditure and energy loss in excreta or in body composition in terms of fat and protein. Only the fatty acid composition in the body was affected by the treatment with TFA. In addition, 50% of ingested TFA was incorporated into the body fat. This may have a negative effect on the dietetic value of chicken meat.

Effect of dietary fat type on meat quality and fatty acid composition of various tissues in growing-finishing swine.

Thirty-six castrated male growing pigs were used to study the effect of dietary beef tallow (BT) versus sunflower oil (SO) on meat quality and fatty acid composition of various tissues. The diets used contained either 5% (w/w) of the variable fat source. The fat type had no significant effect on carcass traits (carcass weight, back-fat thickness, fat-lean ratio) and meat quality (colour, pH(1), pH(U), drip losses, cooking losses, shear force, sacromere length, loin moisture, loin marbling). The diet with SO instead of BT significantly increased the incorporation of polyunsaturated fatty acids in adipose tissues, loin and liver at the expense of the sum of saturated and monounsaturated fatty acids. In erythrocytes, the diet containing SO raised the contents of saturated and polyunsaturated fatty acids and lowered that of monounsaturated fatty acids. In particular, the SO diet produced an increase in the content of linoleic acid (C18:2n-6) in the various tissues. It is concluded that feeding a diet with SO instead of BT altered the fatty acid composition of tissues without simultaneously affecting various characteristics of meat quality.

Plasma lipids and fatty acid composition in parrots in relation to the intake of alpha-linolenic acid from two feed mixtures.

The main objective of this study was to find out whether the content of alpha-linolenic acid (ALA) in plasma cholesteryl-esters (CE) or triglycerides (TG) in parrots might serve as an index of ALA intake. The intake of ALA might be a risk factor for atherosclerosis, but on the basis of the fatty acid composition of seed mixtures the intake is difficult to assess due to selective eating of seeds. Parrots were fed two seed mixtures that differed in ALA content according to a cross over design. The macronutrient composition of the diets supplied differed from that of the diets consumed. The diets consumed had higher levels of dry matter, crude protein, crude fat and energy, and lower levels of crude fibre and crude ash. The ALA content, expressed as g/kg diet, was similar for the diet supplied and that consumed, irrespective of the type of diet. The diets had no systematic effect on plasma lipid concentrations. There were marked differences in plasma cholesterol concentrations between parrot species. When the diet with the low ALA content was fed (0.8% ALA of total fatty acids consumed, 1.1 g ALA/kg of diet consumed), the plasma CE and TG did not contain detectable ALA amounts. When the diet with the high ALA content was fed (4.2% ALA of total fatty acids consumed, 6.1 g ALA/kg of diet consumed), the plasma CE and TG contained about 1% ALA of total fatty acids. It is suggested that the content of ALA in plasma CE and TG might be used as an indicator of ALA intake.

Qualitative risk assessment of chronic renal failure development in healthy, female cats as based on the content of eicosapentaenoic acid in adipose tissue and that of arachidonic acid in plasma cholesteryl esters.

A study was carried out to assess the qualitative risk of development of chronic renal failure (CRF) in young healthy, female cats as based on the content of arachidonic acid (AA) in plasma cholesteryl esters (CE) and eicosapentaenoic acid (EPA) in adipose tissue. It has been suggested that the content of AA in CE should be <10% of total fatty acids (TFA) and of EPA in adipose tissue be >1.4% of TFA. Subcutaneous adipose tissue and blood samples were obtained from 48 female cats. There was a statistically significant correlation between linoleic acid content of adipose tissue and that of plasma CE. In all cats the EPA content of adipose tissue was lower than 1.4% of TFA and in 30 cats that of AA in plasma CE was higher than 10% of TFA. The EPA content of adipose tissue and the AA content of plasma CE are determined by the contents of these fatty acids in the diet. It is concluded that the fatty acid composition of cat foods should be determined and that, if deemed necessary, the ingredient composition should be altered so that the content of EPA is raised and that of AA is lowererd.

The effect of six different C18 fatty acids on body fat and energy metabolism in mice.

We studied the effects of five high-fat semi-purified diets varying at a 4% (w/w) level in either stearic, oleic, linoleic, alpha-linolenic, or gamma-linolenic acid on body fat and energy metabolism in BALB/c mice. A diet containing caprylic, capric, lauric, and myristic acid was used as a reference diet and a diet with 4% conjugated linoleic acid (CLA) was used as a positive control as it is known to effectively lower body fat in mice. The diets were fed for 35 d. Body fat was significantly lower in the CLA group than in the other groups but was not significantly different among the non-CLA groups. Among the non-CLA groups, the linoleic acid group tended to have the highest and the alpha-linolenic acid group the lowest proportion of body fat. In energy-balance studies, the percentage of energy intake that was stored in the body was significantly lower in the CLA group compared with the other dietary groups. The percentage of energy intake eliminated in excreta was highest in the stearic acid group followed by the gamma-linolenic acid group. These results were reflected in apparent fat digestibility, which was lowest in the stearic acid group. The percentage of energy intake expended as heat was highest in the CLA-fed mice. The results of the present study suggest that body fat and energy accretion in mice fed diets containing different C18 fatty acids is by far the lowest with CLA and that linoleic acid produced the highest fat intake and energy accretion.

Interactions of dietary polyunsaturated fatty acids and vitamin E with regard to vitamin E status, fat composition and antibody responsiveness in layer hens.

1. Effects of dietary polyunsaturated fatty acids (PUFA) and vitamin E (VE) on an immune response may interact because VE may protect PUFA from in vivo oxidation. The present study was designed to study the presence of such an interaction in growing layer chickens. 2. Three dietary concentration of linoleic acid (LA, 3.3, 6.6 and 10%), in combination with 4 concentration of dietary VE (5, 20, 40 and 80 mg/kg) were used. Effects of LA and VE on circulating VE concentration, fatty acid composition of bursal and adipose fat, and antibody kinetics against keyhole limpet hemocyanin and Mycobacterim butyricum were established. 3. At high dietary LA concentration, bursal and adipose LA were higher but bursal arachidonic acid and long chain n-3 PUFA decreased. The dietary VE level did not consistently affect the deposition of PUFA in tissue. Plasma VE concentrations were affected by the dietary VE and LA content, but not by their interaction. Antibody responses before and 7 d after immunisation were affected by the dietary treatments. Antibody concentration were not affected by tissue fatty acid content. 4. In conclusion, the interaction effects of dietary PUFA and VE on fat deposition and immune responses are of minor importance compared to separate PUFA and VE effects. This implies that, within the studied range, adding extra VE to preserve or affect the effects of dietary PUFA on antibody responsiveness is unnecessary.

Effects of the flavonoids quercetin and apigenin on hemostasis in healthy volunteers: results from an in vitro and a dietary supplement study.

Intake of dietary flavonols and flavones was inversely associated with risk for cardiovascular disease in several epidemiologic studies. This may have been due to effects on hemostasis because flavonoids have been reported to inhibit platelet aggregation in vitro. We indeed found that 2500 micromol/L of the flavonol quercetin and the flavone apigenin significantly inhibited collagen- and ADP-induced aggregation in platelet-rich plasma and washed platelets by approximately 80-97%. However, lower concentrations, such as might occur in vivo, had no effect. To test this in vivo we fed 18 healthy volunteers 220 g onions/d providing 114 mg quercetin/d, 5 g dried parsley/d providing 84 mg apigenin/d, or a placebo for 7 d each in a randomized crossover experiment with each treatment period lasting 2 wk. Onion consumption raised mean plasma quercetin concentrations to 1.5 micromol/L; plasma apigenin could not be measured. No significant effects of onions or parsley were found on platelet aggregation, thromboxane B2 production, factor VII, or other hemostatic variables. We conclude that the antiaggregatory effects of flavonoids seen in vitro are due to concentrations that cannot be attained in vivo. Effects of dietary flavonols and flavones on cardiovascular risk are possibly not mediated by hemostatic variables.

Diterpenes from coffee beans decrease serum levels of lipoprotein(a) in humans: results from four randomised controlled trials.

OBJECTIVE: Unfiltered coffee raises serum LDL cholesterol in humans, owing to the presence of the diterpenes cafestol and kahweol. Norwegians with a chronic high intake of unfiltered coffee also has elevated serum levels of lipoprotein(a), an LDL-like particle which is insensitive toward dietary interventions. We now experimentally studied the influence of coffee diterpenes on lipoprotein(a) levels. DESIGN: Four randomised controlled trials. SUBJECTS: Healthy, normolipidemic volunteers. INTERVENTIONS: Coffee, coffee oil, and pure diterpenes for 4-24 weeks. MAIN OUTCOME MEASURES: The circulating level of lipoprotein(a). RESULTS: In 22 subjects drinking five to six strong cups of cafetiere coffee per day, the median fall in lipoprotein(a) was 1.5 mg/dL after two months (P = 0.03), and 0.5 mg/dL after half a year (P > 0.05), relative to 24 filter coffee drinkers. Coffee oil doses equivalent to 10-20 cups of unfiltered coffee reduced lipoprotein(a) levels by up to 5.5 mg/dL (P < 0.05) in two separate trials (n = 12-16 per group). A purified mixture of cafestol and kahweol, as well as cafestol alone, were also effective in reducing Lp(a) levels (n = 10). Averaged over the four trials, each 10 mg/d of cafestol (plus kahweol)--the amount present in two to three cups of cafetiere coffee--decreased Lp(a) levels by 0.5 mg/dL or 4% from baseline values after four weeks (n = 63). CONCLUSIONS: Coffee diterpenes are among the few dietary exceptions shown to influence serum lipoprotein(a) levels. However, the Lp(a)-reducing potency of coffee diterpenes may subside in the long run, and their adverse side effects preclude their use as lipoprotein(a)-reducing agents.

Chronic consumers of boiled coffee have elevated serum levels of lipoprotein(a).

OBJECTIVES: Lipoprotein(a) consists of an LDL-particle attached to apolipoprotein(a), which is made by the liver. Diterpenes present in boiled coffee raise serum levels of LDL cholesterol and of the liver enzyme alanine aminotransferase in man. We investigated the association between intake of boiled coffee and serum levels of lipoprotein(a). DESIGN, SETTING AND SUBJECTS: Healthy Norwegians 40-42 years of age, who habitually consumed five or more cups of boiled coffee per day (n = 150) were compared with matched filter coffee consumers (n = 159) in a cross-sectional study, as part of the Norwegian National Health Screening in 1992. RESULTS: The median lipoprotein(a) level was 13.0 mg dL-1 (10th and 90th percentile: 2.5 and 75.0 mg dL-1, respectively) on boiled and 7.9 mg dL-1 (10th and 90th percentile: 1.9 and 62.5 mg dL-1, respectively) on filter coffee (P = 0.048). Means +/- SE were 25.8 +/- 2.4 mg dL-1 and 19.6 +/- 2.0 mg dL-1, respectively (P = 0.04). Although not statistically significant, subjects consuming nine or more cups of coffee per day had higher lipoprotein(a) levels than those drinking five to eight cups per day in both coffee groups. CONCLUSION: Chronic consumers of unfiltered, boiled coffee have higher serum levels of lipoprotein(a) than filter coffee drinkers.

Supplemental vitamin A enhances the recovery from iron deficiency in rats with chronic vitamin A deficiency.

Studies with anaemic children and pregnant women from areas where vitamin A deficiency is endemic have shown a beneficial effect on Fe status of supplemental vitamin A in addition to Fe supplementation. This suggests a relationship between vitamin A and Fe status, which we attempted to mimic in rats with anaemia and chronic vitamin A deficiency. Male rats were fed on Fe-adequate diets (35 mg Fe/kg) containing different levels of vitamin A (1200, 450, 150, 75 and 0 retinol equivalent (RE)/kg feed) until they were 5 weeks old. These diets were identical to the diets fed to their mothers. Then the young male rats were transferred to diets containing the same levels of vitamin A but no added Fe. After another 2 weeks the rats were repleted with Fe (35 mg/kg feed) without or with vitamin A to a level of 1200 RE/kg feed. Increased vitamin A intake by the groups previously fed on diets with either 0 or 75 RE/kg produced a reduction in blood haemoglobin concentration, packed cell volume and erythrocyte count. In the group which had been fed on the diet without vitamin A, supplemental vitamin A raised mean cell volume, plasma Fe concentration and total Fe-binding capacity. Vitamin A supplementation during the period of Fe repletion produced a decrease in splenic and tibia Fe concentration, the effect being greater with increasing severity of previous vitamin A deficiency. The paradoxical effect of supplemental vitamin A on haemoglobin, packed cell volume and erythrocyte count can be explained by a decrease in the degree of haemoconcentration. Thus, the positive effect of supplemental vitamin A seen in humans is also observed with rats under controlled experimental conditions. We speculate that supplemental vitamin A during Fe repletion contributes to optimum erythropoiesis and Fe mobilization when baseline vitamin A status is impaired.

Evaluation of a two-generation rat model for vitamin A deficiency and the interrelationship with iron metabolism.

In order to induce a range of vitamin A-deficient states in young growing rats and to study the effect of vitamin A deficiency on Fe status, we designed the following two-generation experiment. Dams were fed on diets with one of five vitamin A levels from 2 weeks before and throughout pregnancy and lactation. The pups received the same diets as their mothers both before and after weaning. The five dietary levels of vitamin A were 1200, 450, 150, 75 and 0 retinol equivalents/kg feed. Vitamin A intake did not affect reproduction outcome, nor were body and liver weights of the pups affected when they were 3.5 weeks old. Male pups with normal vitamin A status had higher plasma retinol levels than female pups. Vitamin A status of the offspring was affected from 3.5 weeks onwards. Body and liver weights were decreased in the male pups given the lowest dietary vitamin A levels from week 6.5 onwards but not in the female pups. Fe status was marginally affected. Haemoglobin levels were increased and total Fe-binding capacity was decreased in the groups given no dietary vitamin A at week 9.5. Splenic Fe was increased only in the male pups given the lowest levels of dietary vitamin A. However, as a whole, Fe status was only mildly affected and subject to considerable variation. We conclude that the two-generation rat model described here is not suitable for studying effects of vitamin A deficiency on Fe metabolism.

Repeatability of taste panel tenderness scores and their relationships to objective pig meat quality traits.

Repeatabilities of 12 meat quality measurements were calculated as a value for the accuracy of those measurements. Sixty-four Duroc and Dutch Yorkshire boars and gilts were slaughtered during 8 wk. The repeatabilities between carcass halves within animals were .53 for repeated taste panel tenderness scores based on 12.4 observations of different panelists per mean, .08 for two repeated tenderness scores of different panelists within one animal, .50 for two repeated tenderness scores of one panelist within one animal, and 41 for repeated measurements of maximum shear force. Repeatabilities of other meat quality traits ranged from .29 for cooking loss to .76 for the Minolta L* color coordinate. The phenotypic correlation between tenderness assessed by a panel and maximum shear force was -.50. The phenotypic correlation between those traits corrected for measurement errors was -.74. A correlation of zero was found between the total amount of collagen and meat tenderness, between amount of intramuscular fat and tenderness, and between ultimate pH and tenderness. The other correlations with meat tenderness ranged from -.00 for Minolta b* color coordinate to -.44 for drip loss. It was concluded that the measurement of maximum shear force can be used as an effective indicator of pig meat tenderness.

Economic values of optimum traits: the example of meat quality in pigs.

In this paper a method is outlined to derive marginal-income functions and to calculate economic values for traits with an intermediate optimum such as meat-quality traits. A normal distribution of the quality trait was assumed, but the method can be used for other distributions as well. The parameters necessary to use this method are distribution of the quality trait, population mean and the standard deviation of the quality trait, optimum range, and price differences between products within and outside the optimum range. Especially, the optimum range for the quality trait and the price differences to be used have to be derived from consumer and processing research. Some alternative methods that can be used for selection on quality traits, such as restricted selection index, desired-gains index, and indices based on a quadratic aggregate genotype, are discussed.