Protein retention, growth performance and carcass traits of individually housed immunocastrated male- and female- and surgically castrated male Iberian pigs fed diets of increasing amino acid concentration.

Immunocastration (IC, vaccination against gonadotropin releasing hormone (GnRH)) is one alternative to surgical castration (SC) for preventing sexual development and boar taint in male pigs. A temporal increase in performance has been described for IC pigs before the second vaccination against GnRH. The objective of this work was to assess the effects of IC on Iberian male and female pigs (fed diets of increasing CP content) on performance, nitrogen retention (NR) and digestibility, and carcass traits. Fifty-four pure Iberian pigs individually housed were allocated to a 3 × 3 factorial arrangement with three sex groups (IC males, IC females and SC males), three diets (153, 137 and 119 g CP/kg DM; 14 MJ metabolisable energy/kg DM) and six pigs per treatment combination. Pigs were vaccinated at 18 weeks of age (40 kg BW) and seven weeks later (70-80 kg BW) and fed at 0.9 × ad libitum on BW basis. Two digestibility and nitrogen balance assays were performed before and after the second vaccination, respectively. Pigs were slaughtered at 105 kg BW. Before the second vaccination, Iberian IC males showed higher growth rate (g/day), feed efficiency, NR (g/day) and efficiency of NR than the other groups (P < 0.001). The NR and efficiency of NR was 40% greater in IC v. SC males (P < 0.001). After the second vaccination, no differences in performance between sex groups were detected (P > 0.05). Growth rate and feed efficiency were higher in IC males than in the other groups for the whole experimental period (from the first vaccination to slaughter; P < 0.001). After the second vaccination, differences among sex groups in NR and the efficiency of NR disappeared (P > 0.05). NR efficiency was 0.177 on average. No significant effects of dietary CP were detected on performance. The NR was greater in pigs fed the 153 CP diet (17 to 37%; P > 0.05). Lean components of carcass (sirloin, loin and butt lean) were greater in IC males than in the other groups (0.001 < P < 0.05). There were no significant sex group×dietary CP interactions. Iberian IC males grew at higher rate, deposited more protein, and more efficiently, than Iberian SC males before the second vaccination against GnRH. Iberian IC females showed similar growth performance to SC males and intermediate protein deposition efficiency between IC and SC males. Despite the higher growth performance, protein deposition rate, and efficiency of protein deposition of IC males v. SC males, no significant differences in amino acid requirements were detected between them.

Effects of lysine deficiency on carcass composition and activity and gene expression of lipogenic enzymes in muscles and backfat adipose tissue of fatty and lean piglets.

The purpose of this study was to investigate potential mechanisms involved in fat deposition promoted by dietary lysine deficiency, particularly intramuscular fat (IMF), and differential responses between fatty and lean pigs. Carcass traits and lipogenic enzyme activities and gene expression levels in muscles and adipose tissue were investigated in Iberian (fatty) and Landrace × Large White (LDW) pigs under identical feeding level (based on body weight (BW)) and management conditions. Twenty-eight barrows of 10 kg initial BW, 14 per breed, were fed two isoproteic (200 g CP /kg DM) and isocaloric (14.7 MJ metabolizable energy/kg DM) diets with identical composition except for the lysine content (1.09% for diet adequate in lysine and 0.52% for diet deficient in lysine). At a BW of 25 kg, pigs were slaughtered. Compared with pigs fed the lysine-adequate diet, in both genotypes lysine-deficient diet led to lower carcass protein concentration, lower relative proportions of leaner components (loin, ham and shoulder; P < 0.01), and higher carcass fatty components and carcass lipid concentration (P < 0.001). Irrespective of diet, the activity and gene expression of lipogenic enzymes (fatty acid synthase (FAS), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH)) were greater in Iberian than in LDW pigs, particularly in adipose tissue where transcriptional regulators involved in the control of adipogenesis and lipogenesis were also upregulated in Iberian animals. In backfat tissue, there was a small decrease induced by or no effects of lysine-deficient diet on the activity and gene expression of lipogenic enzymes, nor in gene expression levels of upstream regulators of lipogenesis and adipogenesis. In longissimus muscle, the activity of FAS, G6PDH and ME increased with lysine deficiency in both genotypes (P < 0.01) and an upregulation of gene expression of lipogenic enzymes was specifically observed in Iberian pigs (P < 0.05 to P < 0.001). In biceps femoris muscle of lysine-deficient pigs, the activity of FAS and ME enzymes increased, ME1 gene was upregulated (added to FASN gene in the case of Iberian pigs; P < 0.01 to P < 0.001) and PPARA gene was downregulated (P < 0.05). The results show that in both fatty and lean pigs, the effect of lysine deficiency on lipid metabolism was tissue-specific, with an activation of lipogenesis in longissimus and biceps femoris muscle but no apparent stimulation in backfat adipose tissue. Suitable feeding protocols including lysine-deficient diets should be designed for each pig type in order to increase intramuscular lipids without penalizing the growth of lean carcass components.

Similar effects of lysine deficiency in muscle biochemical characteristics of fatty and lean piglets.

The main objective of this work was to investigate the effects of feeding Lys-deficient diets on muscle biochemical characteristics, particularly intramuscular fat concentration and fatty acid profile, in a fatty (Iberian) and a conventional pig genotype (Landrace × Large White [LDW]) maintained in identical experimental conditions. Performance and plasma metabolite changes were also monitored. Twenty-eight barrows of 10 kg initial BW, 14 of Iberian and 14 of LDW breed, were randomly assigned to each of 2 experimental diets in a 2 × 2 factorial arrangement (2 breeds × 2 diets). Seven pigs were allocated to each treatment combination. Diets (isonitrogenous and isoenergetic; 200 g CP/kg DM and 14.7 MJ ME) based on barley, corn, corn gluten meal, and soybean meal, with identical composition, except for their Lys content (10.9 g/kg for the diet adequate in Lys and 5.2 g/kg for the diet deficient in Lys), were assayed. Pigs were housed in individual 2 m pens and fed at 85% of ad libitum intake of the Iberian genotype, of greater intake capacity. Daily feed allowance was based on BW individually measured each week. At 25 kg BW, pigs were slaughtered by exsanguination after electrical stunning. Blood samples were taken and longissimus dorsi and biceps femoris muscles were rapidly dissected and stored frozen prior to analysis. Performance was reduced in both pig breeds when fed Lys-deficient diets, particularly in LDW pigs (breed × diet interaction, < 0.05). Intramuscular fat content increased in longissimus dorsi of Iberian ( < 0.05) and in biceps femoris of both pig genotypes ( < 0.01) when fed Lys-deficient diets. Oleic acid increased ( < 0.05) and PUFA acid decreased ( < 0.01) in longissiumus dorsi and biceps femoris of pigs of both genotypes fed Lys-deficient diets. The proportion of oxidative fibers ( < 0.001) and free carnitine content ( < 0.05) increased in longissimus dorsi of both pigs types fed Lys-deficient diets. Plasma creatinine was greater in LDW pigs compared with Iberian pigs ( < 0.01). Urea and total cholesterol increased in pigs consuming Lys-deficient diets ( < 0.01). The plasma free carnitine concentration was higher in Iberian pigs than in LDW pigs ( < 0.059). No changes in plasma carnitine status due to dietary Lys supply were detected. Feeding Lys-deficient diets could be a suitable strategy for increasing intramuscular fat content in fatty and lean pigs.

Effects of intermittent suckling on body composition of Iberian piglets weaned at 35 days of age.

Piglet body composition at weaning could be a determinant for pig's viability and may be influenced by factors such as the nutritional management followed during suckling. An experiment was conducted to study whether intermittent suckling (IS) affects body composition at weaning and nutrient and energy retention during a 34-day lactation period in Iberian piglets. Litters were subjected to conventional suckling (CS) or IS (n=10 litters of six piglets per treatment) in two trials. All piglets had ad libitum access to creep feed from day 15 onwards. In IS, piglets were progressively separated from the sow for 6, 8 and 10 h daily during the last week of lactation, whereas in CS piglets had continuous access to their dams. Creep feed intake in litters and BW development of individual piglets were measured throughout the 34-day lactation. Within each litter, both at birth and at weaning (day 35), one piglet was used to assess nutrient retention and body composition by the comparative slaughter approach. During days 29 to 35 of the experiment, daily creep feed intake was greater in IS piglets (IS 124, CS 67 g/piglet, P=0.040), and average daily gain differed significantly between groups (IS 190, CS 150 g/day, P=0.010). BW at weaning was higher in the IS than in the CS piglets (IS 8.19, CS 7.48 kg, P=0.011). Empty-body fat and energy content at weaning were higher in the IS compared with CS litters, as well as fat content in the carcass (P=0.04). The IS treatment did not affect empty-body protein deposition, but significantly increased daily retention of fat, energy, ash and calcium, compared with CS litters (P<0.05). Thus, IS in Iberian piglets seems to enhance feed intake, growth rate and retention of some body components, which may contribute to a higher body fat content at weaning and facilitate the weaning process.

Dietary protein excess does not influence calcium and phosphorus absorption and retention in Iberian pigs growing from 50 to 100 kg body weight.

Effects of apparent total tract digestible dietary protein [expressed as apparent ileal digestible (AID) Lys in parentheses] from excessive to marginally deficient [110 (7.9), 92 (6.6), 73 (5.3) and 54 (3.8) g/kg DM] and feeding level (FL; 0.80 and 0.95 × ad libitum) upon fractional absorption and retention of Ca and P was studied in 48 purebred Iberian barrows from 50 to 100 kg BW to investigate possible detrimental effects of protein over supply on Ca and P metabolism. The diets were prepared by diluting a high-protein diet, formulated according to the ideal protein concept, with a protein-free mixture. The diets provided (per kg DM) 11.6 to 10.7 g Ca, 6.67 to 6.25 g total P, and 13.9 to 14.8 MJ ME. Intake levels with free access to feed were calculated according to individual BW and were adjusted weekly. A digestibility and balance trial was performed at 75 kg BW. The ADFI was 3104 and 2643 g for 0.95 and 0.80 × ad libitum FL. The ADG reached a maximum at 854 g (18.87 g/MJ ME intake) with the diet containing 5.3 g AID Lys/kg DM. Dietary AID Lys content did not alter Ca and P fractional apparent absorption, which attained average values of 0.417 ± 0.0109 and 0.545 ± 0.0106. The Ca and P retention as a fraction of intake remained unaffected at 0.403 ± 0.0114 and 0.403 ± 0.0120. The Ca urinary losses were not elevated by excess of dietary protein supply, remaining at 0.260 ± 0.0212 g/d. High feeding level increased (P < 0.05) the flow of absorbed Ca and P. In conclusion, long-term, high-protein (Lys) intake did not affect Ca intestinal absorption and renal excretion in the pig.

Assessing the effects of severe heat treatment of milk on calcium bioavailability: in vitro and in vivo studies.

Thermal processing of milk is a common practice. As milk is the main source of dietary calcium, this study aimed to assess the effects of overheating milk on calcium availability. Thus, thermally damaged milk (overheated, OH, milk; 3 cycles of sterilization at 116 °C, 16 min) was compared with UHT milk (150 °C, 6s) in 2 types of assays: in vitro and in vivo (rats). In addition, the greater Maillard reaction rate associated with thermal treatment in OH milk was confirmed by determining specific (furosine) and unspecific markers (CieLab color). A negative effect on calcium solubility was observed after in vitro digestion of OH milk compared with UHT milk. Feeding rats the diet containing OH milk as the protein source led to significantly lower values of apparent calcium absorption and retention than those found among animals fed the UHT milk diet. Whereas reducing the absorption appears to result mainly from the decreased food intake, the negative effect on retention seems to be due to factors derived from milk thermal damage, such as the formation of Maillard reaction products. It was concluded that milk-processing conditions warrant special attention to prevent impaired dietary calcium utilization. This may be especially important in situations where milk and dairy products are the main dietary components, such as in early infancy.

Ingesta de sodio en la dieta de un colectivo de adolescentes / Sodium intake in the diet of a group of adolescents

Los cambios en los hábitos alimentarios de la población han conducido a un incremento en la ingesta de sodio, debido, fundamentalmente, al aumento del consumo de alimentos de fabricación industrial, en detrimento de los preparados en el hogar. Estos cambios se acentúan especialmente en el colectivo adolescente, ya que frecuentemente incluyen en su dieta refrescos, snacks o fast-food, con elevado contenido de sal o aditivos con sodio. Es conocida la relación directa entre la ingesta dietética de sodio y la presión sanguínea, asociándose una ingesta elevada a hipertensión y a enfermedades cardiovasculares. Además, el sodio puede incrementar la eliminación de calcio en la orina, potenciando las pérdidas óseas, por lo que puede ser un factor de riesgo importante para el desarrollo de osteoporosis. En este estudio se realizó una encuesta alimentaria a 21 adolescentes varones de 11-14 años, con el fin de estimar la ingesta de sodio en su dieta habitual y la contribución de los distintos grupos de alimentos. Para ello se evaluó la ingesta de tres días, mediante recordatorio de 24 horas y registro de ingesta de dos días. Los datos del consumo de alimentos fueron transformados en valores de energía y nutrientes mediante tablas de composición de los alimentos. Los adolescentes consumieron una media de 4558 mg de sodio/día, superando en gran medida las recomendaciones actuales del micronutriente. Las conservas y precocinados fueron los alimentos que proporcionaron el mayor porcentaje del elemento en la dieta (23,5%). Debido al elevado consumo de sodio entre los adolescentes, se recomienda disminuir su ingesta, evitando especialmente un consumo excesivo de alimentos procesados, ricos en sodio. Con esto se pretende prevenir posibles problemas de salud en el futuro, como hipertensión u osteoporosis(AU)

Changes in the dietary habits of the population have led to an increase of sodium intake, mainly due to the great intake of manufactured products and the low consumption of homemade foods. These changes are especially important among adolescents, since they frequently include soft drinks, snacks or fast-food in their diets, foods with a high salt content or including sodium-rich additives. It is known the strong relationship between dietary sodium intake and blood pressure: a high sodium intake is related with hypertension and also with cardiovascular diseases. Moreover, sodium intake is associated with increased urinary calcium, therefore increasing bone losses. This fact might be an important risk factor for osteoporosis development. In the present study a dietary questionnaire was realized to 21 male adolescents aged 11-14 years, in order to calculate the sodium intake under their habitual diet and the contribution of the different food sources. The food intake was monitored during a 3-day period, by combining a 24-hour diet recall and two-days weighed dietary record. Data of food consumption were transformed into energy and nutrient vales using tables of food composition. Adolescents consumed an average of 4558 mg/day of sodium, overcoming in a great amount the current recommendations for this micronutrient. Canned and precooked foods contributed the highest percentage of the element in the diet (23.5%). According to these data, it would be extremely advisable to reduce sodium intake among adolescents, avoiding especially excessive processed food consumption, rich in sodium. These actions would be aimed to preventing possible diseases in adulthood such as hypertension and osteoporosis(AU)

Longitudinal study of the simultaneous secretion of melatonin and leptin during normal puberty.

BACKGROUND/AIMS: Pubertal changes are a consequence of the activation of the hypothalamic-pituitary-gonadal axis due to an increase in the frequency and magnitude of pulses of gonadotropin-releasing hormone (GnRH), which may depend on the intrinsic properties of the neurons of the hypothalamic arcuatus nucleus, or on the influence of neurotransmitters and/or neuromodulators. We evaluated the serum concentrations of melatonin and leptin in healthy prepubertal and adolescent subjects of both sexes, to define their participation at the initial stages and during the progression of pubertal development. METHODS: 80 pediatric subjects (47 females and 33 males), aged 6-18 years, were divided into 2 groups, prepubertal (n = 25) and adolescent (n = 55), according to the absence or presence, respectively, of physical signs of pubertal development. The subjects were assessed on two occasions: at the time of their inclusion in the study, and 12-18 months later when the subject had advanced one pubertal stage according to the Tanner classification. Blood was obtained in fasting for clinical purposes and for the hormonal study. Melatonin and leptin were measured by radioimmunoanalysis. RESULTS: As described previously, melatonin decreases at the onset of puberty and during pubertal development. Both the absolute melatonin value and the decrease between evaluations tended to be greater in females; the variations were correlated with neither an increase in body weight nor with the degree of pubertal development. The concentration of leptin increased in both sexes with the progression of puberty, this value being 40% greater in women, and correlated with the indicators of an increase in body volume and fat accumulation. Although its concentration remained stable between evaluations for both sexes, among the males the association between leptin and pubertal development took place at the start of the process, while for the females we observed a significant overall association between pubertal stage and leptin concentration, this association being stronger at more advanced Tanner stages. Neither at the onset of puberty nor during its course did we observe any significant relation between melatonin concentration and any of the Tanner stages, whether for males or for females. Neither was there any correlation between the absolute values or rates of modification of melatonin and leptin. CONCLUSION: According to the evolutionary dynamics of their respective concentrations, both initially and during pubertal progress, melatonin and leptin do not interact in the initiation or progression of human pubertal development, and do not seem to play a key role in this process.

Dietary calcium utilization among a group of Spanish boys aged 11-14 years on their usual diets.

Adolescence constitutes a period of nutritional vulnerability due to increased dietary requirements for growth and development and special dietary habits. A pilot trial was performed to evaluate the dietary calcium utilization among a sample of Spanish boys on their usual diets, in which the calcium intake and consumption of dairy products were as well examined. Nutrient and food intake was recorded using a 24-h dietary recall and a 2-d food consumption record for 21 subjects aged 11-14 years. Dietary calcium utilization was assessed by means of calcium intake in food and calcium output in faeces and urine as measured by flame atomic absorption spectrophotometry. Overall intake of dairy products was 399.3 +/- 22.1 g/d, and the single most consumed item was milk (72% of the total). An inverse relationship was found between dairy product consumption at breakfast (55% of the total) and BMI (p = 0.016, r = -0.5168). Dairy products contributed the majority of dietary calcium (66.9%). Mean calcium intake was 881.7 +/- 39.9 mg/d, 88% of the recommended value for Spanish adolescents. Net calcium absorption (271.7 +/- 51.7 mg/d) and retention (170.6 +/- 50.9 mg/d) seemed not to be sufficient to meet growth demands during puberty. The results shown that adolescents of the study absorbed 31% of dietary calcium and retained nearly 20% of the total intake, but dietary calcium intake and consumption of dairy products failed to meet recommended values. Optimizing calcium intake is of crucial importance among adolescents, to maximize calcium retention and to help prevent osteoporosis in later life.

Dietary calcium utilization among a group of Spanish boys aged 11-14 years on their usual diets

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Adolescence constitutes a period of nutritional vulnerability due to increaseddietary requirements for growth and development and special dietary habits. A pilottrial was performed to evaluate the dietary calcium utilization among a sample ofSpanish boys on their usual diets, in which the calcium intake and consumption ofdairy products were as well examined. Nutrient and food intake was recorded usinga 24-h dietary recall and a 2-d food consumption record for 21 subjects aged 11-14years. Dietary calcium utilization was assessed by means of calcium intake in foodand calcium output in faeces and urine as measured by flame atomic absorption spectrophotometry.Overall intake of dairy products was 399.3±22.1 g/d, and the singlemost consumed item was milk (72% of the total). An inverse relationship was foundbetween dairy product consumption at breakfast (55% of the total) and BMI(p=0.016, r=-0.5168). Dairy products contributed the majority of dietary calcium(66.9%). Mean calcium intake was 881.7±39.9 mg/d, 88% of the recommended valuefor Spanish adolescents. Net calcium absorption (271.7±51.7 mg/d) and retention(170.6±50.9 mg/d) seemed not to be sufficient to meet growth demands duringpuberty. The results shown that adolescents of the study absorbed 31% of dietarycalcium and retained nearly 20% of the total intake, but dietary calcium intake andconsumption of dairy products failed to meet recommended values. Optimizing calciumintake is of crucial importance among adolescents, to maximize calcium retentionand to help prevent osteoporosis in later life

[Effects of intake of heated mixtures of glucose-lysine and glucose-methionine on bone calcium]. / Repercusiones del consumo de mezelas calentadas de glucosa-lisina y glucosa-metionina sobre el calcio óseo.

During food thermal treatment Maillard's reaction may occur, which implicates mainly the carbonyl groups of reductory sugars and amino protein groups. Maillard's reaction products (MRP) may interfere with mineral bioavailability because of modifications of their physical-chemical moiety in the food or the lumen, disrupting the absorption process or its normal metabolism. In this study, we sought to investigate MRP influence on issues related to Ca bioavailability in vitro and in vivo. Equimolar mixtures of glucose-lysine (GL) and glucose-methionine (GM) (40% moisture) were heated at 150 degrees C for 90 minutes (samples GL90 and GM90, respectively). In vitro solubility was measured by additioning each samples to a 3.75 mM Ca solution at intestinal pH and ionic strength; after shaking and centrifugation, soluble and insoluble calcium was determined. Three percent of GL90 and GM90 were individually added to the AIN93-G diet to obtain D-GL90 and D-GM90 diets. Three Wistar rats groups were fed for 21 days with both diets and with AIN93-G as control, carrying out calcium balance during last week and extirpating various organs after sacrifice. GM90 did not affect calcium solubility; GL90 reduced it slightly, remaining in both cases more than 94% soluble. D-GL90 and D-GM90 did not modify calcium bioavailability, with as effective usage as with the control diet (57.6 +/- 1.3%, 57.8 +/- 2.3% and 63.9 +/- 2.6% in control diet, D-GL90 and D-GM90, respectively). MRP intake produced, however, metabolic changes that decreased bone calcium, accumulating compensatorily in other organs.

Repercusiones del consumo de mezclas calentadas de glucosa-lisina y glucosa-metionina sobre el calcio óseo / Effects of intake of heated mixtures of glucose-lysine and glucose-methionine on bone calcium

Durante el tratamiento térmico de los alimentos puede desarrollarse la reacción de Maillard, que tiene lugar, fundamentalmente, entre los grupos carbonilo de azúcares reductores y los grupo amino proteicos. Los productos de la reacción de Maillard (PRM) pueden afectar la biodisponibilidad mineral por modificaciones de su forma físico-química en el alimento o en el lumen, alterando el proceso de absorción o su normal metabolismo. En este trabajo se estudió la influencia de PRM sobre aspectos de la biodisponibilidad del Ca in vitro e in vivo. Mezclas equimolares de glucosa-lisina (GL) y glucosa-metionina (GM) (40% humedad) fueron calentadas a 150º C durante 90 minutos (muestras GL90 y GM90, respectivamente). La solubilidad in vitro se midió adicionando cada muestra a una solución 3,75 mM Ca con pH y fuerza iónica del intestino; tras agitación y centrifugación se determinó el calcio soluble e insoluble. Un 3% de GL90 y GM90 se añadieron individualmente a la dieta AIN93-G para la obtención de las dietas D-GL90 y D-GM90. Con ellas y con la AIN93-G, como control, se alimentaron durante 21 días tres grupos de ratas Wistar, realizándose balance de calcio en la última semana y, tras sacrificio, extracción de distintos órganos. La presencia de GM90 no afectó a la solubilidad del calcio; GL90 la disminuyó ligeramente, quedando en ambos casos más del 94% soluble. El consumo de D-GL90 y D-GM90 no modificó la biodisponibilidad del elemento, utilizándose tan eficazmente como en la dieta control (57,6 ± 1,3%, 57,8 ± 2,3% y 63,9 ± 2,6% en las dietas control, D-GL90 y D-GM90 respectivamente). Sin embargo, la ingesta de los PRM produjo cambios en el metabolismo que disminuyeron el calcio óseo, acumulándose de forma compensatoria en otros órganos (AU)

During food thermal treatment Maillard's reaction may occur, which implicates mainly the carbonyl groups of reductory sugars and amino protein groups. Maillard's reaction products (MRP) may interfere with mineral bioavailability because of modifications of their physical-chemical moiety in the food or the lumen, disrupting the absorption process or its normal metabolism. In this study, we sought to investigate MRP influence on issues related to Ca bioavailability in vitro and in vivo. Equimolar mixtures of glucose-lysine (GL) and glucose-methionine (GM) (40% moisture) were heated at 150º C for 90 minutes (samples GL90 and GM90, respectively). In vitro solubility was measured by additioning each samples to a 3.75 mM Ca solution at intestinal pH and ionic strength; after shaking and centrifugation, soluble and insoluble calcium was determined. Three percent of GL90 and GM90 were individually added to the AIN93-G diet to obtain D-GL90 and D-GM90 diets. Three Wistar rats groups were fed for 21 days with both diets and with AIN93-G as control, carrying out calcium balance during last week and extirpating various organs after sacrifice. GM90 did not affect calcium solubility; GL90 reduced it slightly, remaining in both cases more than 94% soluble. D-GL90 and D-GM90 did not modify calcium bioavailability, with as effective usage as with the control diet (57.6 ± 1.3%, 57.8 ± 2.3% and 63.9 ± 2.6% in control diet, D-GL90 and D-GM90, respectively). MRP intake produced, however, metabolic changes that decreased bone calcium, accumulating compensatorily in other organs (AU)

Effects of heat treatment of casein in the presence of reducing sugars on calcium bioavailability: in vitro and in vivo assays.

Casein-glucose-fructose mixtures unheated (C) or after heating (HC) were added to a solution of ionic calcium to study calcium speciation and included in diets (C-D, HC-D) for rats. Samples and diets were digested in vitro. Supernatants of digested samples were used for transport experiments with Caco-2 cells. Total soluble and ionic calcium levels were lower and precipitated calcium levels higher with HC compared to C. Dialyzed calcium from the diets was highly ionic and lower in HC-D compared to C-D. Nondialyzed soluble calcium was also lower, whereas precipitated calcium was higher, in HC-D. HC increased calcium transport in Caco-2 cells compared to C, but transport efficiency decreased due to lower calcium solubililty after digestion. Urinary calcium increased with HC-D consumption without changes in calcium absorbed and retained. Maillard reaction products in HC decrease calcium solubility, but enterocyte metabolism and calcium absorption and retention seem to be unaffected. Nevertheless, urinary calcium losses increase.

Zinc transport in Caco-2 cells and zinc balance in rats: influence of the heat treatment of a casein-glucose-fructose mixture.

The effects of the heat treatment of casein in the presence of glucose-fructose on Zn bioavailability were studied. Changes in Zn speciation were compared after in vitro digestion of heated (HC) and unheated mixture (C) alone and as part of the diet. The uptake and transport of digested soluble Zn was investigated in Caco-2 cells grown in bicameral chambers; balance studies were done in rats fed diets containing the different samples. After in vitro digestion, the precipitated Zn was significantly higher in HC than in C. In assays with Caco-2 cells, the amount of Zn transferred from the apical to the basolateral chamber was significantly greater when the culture medium contained raw or heated casein. However, because a larger proportion of Zn was precipitated by in vitro digestion, Zn utilization was less efficient in the presence of casein. In biological experiments, food efficiency of the heated casein-glucose-fructose diet was lower, and feeding this diet increased the urinary Zn excretion and lowered Zn absorption and retention. The effects of browning products generated during food processing should be taken into account, especially in diets containing marginally adequate levels of Zn, to prevent possible deficiency.

Efectos de la intervención nutricional y de otros hábitos de vida en el metabolismo lipídico de pacientes con patología vascular, periférica (fontaine grado ii) / Effetcs of nutritional intervention and lifestyles on lipid metabolism of patients with peripheal vascular disease

La enfermedad vascular periférica (EVP) se caracteriza por arteriosclerosis e isquemia de extremidades inferiores que originan la claudicación intermitente. Los pacientes agrupados en el grado 11 de Fontaine tienen más del 75 por ciento de estenosis orgánica en arterias periféricas y presentan alteraciones en la coagulación y en los lípidos plasmáticos. El objetivo de este estudio fue evaluar de forma controlada la influencia de la ingesta de los aceites de oliva virgen, aceite de oliva refinado y sus mezclas con aceite de pescado, junto con un programa de intervención de hábitos de vida que incluyen recomendaciones dietéticas, ejercicio moderado y descenso del consumo de tabaco, sobre la composición lipidica del plasma, en una población de pacientes con EVP durante un período de 15 meses. El estudio se realizó mediante un diseño aleatorio cruzado en el que 24 pacientes ingerían alternativamente, en períodos de 3 meses, los aceite de oliva virgen, oliva refinado y sus mezclas con un suplemento diario de 16 g de aceite de pescado refinado. Además, se incluyó un grupo control con 13 pacientes que no ingerían de forma habitual estos aceites, aunque sí siguieron el programa de intervención nutricional y de hábitos de vida. Se realizó un estudio de ingesta de alimentos y hábitos de vida cada 3 meses, así como de las modificaciones en la composición lipidica del plasma. Los resultados obtenidos indican que la intervención nutricional individualizada de pacientes con patología vascular por arteriosclerosis consigue que los sujetos incorporen a sus hábitos de vida una alimentación cada vez más sana y equilibrada junto con una disminución del consumo de tabaco y aumento del ejercicio físico moderado, lo que provoca una mejora en su calidad de vida. El consumo del aceite de pescado, conjuntamente con el consumo habitual de aceite de oliva, disminuyó significativamente los niveles de TG plasmáticos comparado con el consumo de aceite de oliva exclusivamente (AU)

Influence of heat treatment of casein in presence of reducing sugars on Zn solubility and Zn uptake by Caco-2 cells after in vitro digestion.

The effect of the heat treatment of casein in presence of reducing sugars on some aspects of Zn availability was investigated. Samples were prepared by mixing casein with glucose-fructose, and were used unprocessed (C) or heated (HC). Changes in Zn speciation after the in vitro digestion of the samples, both as part of a diet and in isolation, were studied. The uptake of soluble Zn from the digested samples was investigated in Caco-2 cells. After in vitro digestion, the percentage of precipitated Zn was significantly higher with the HC sample, both when digested alone and as a part of the diet. In assays with Caco-2 cells, a significant decrease in Zn uptake was observed when the uptake buffer contained the sample C digest, by comparison with the control buffer, without casein digest. When the digested heated mixture was added, Zn uptake by the cells was significantly lower than in either of the two other cases. It may be concluded that the heat treatment of casein in the presence of glucose-fructose has a negative effect on Zn availability because, after in vitro digestion, Zn insolubilization was enhanced and Zn uptake by the enterocyte was impaired, compared with the unheated mixture. In addition, the usefulness of Caco-2 cells in this kind of research has been shown.

Blood platelet function in healthy individuals of different ages. Effects of exercise and exercise conditioning.

The influence of age, physical conditioning and physical exercise on platelet function on human being is still controversial. The aim of our study were to evaluate the effect of physical exercise on platelet activation measured by beta-thromboglobulin (beta-TG) levels and the number of platelets in sedentary and athlete subjects of different ages, and also to investigate the response of these parameters during the period of recover immediately after a bicycle exercise test. Our results show differences in platelet count and beta-TG levels among the experimental groups studied, in basal conditions, in response to the exercise test and during postexercise period. These results seem to indicate that regardless age, regular physical exercise diminish age negative effects on platelet aggregation.

Long-term effects on lipid metabolism in miniature swine (Sus scrofa) of diets enriched in saturated, monounsaturated and polyunsaturated (N-6 and N-3) fatty acids.

In this paper we study the effect of long-term adaptation (twelve months) of lipidic parameters of miniature swine to diets enriched in saturated (lard; L-group), monounsaturated (olive-oil; O-group) and polyunsaturated (sunflower and fish-oil; S- and F-groups respectively). The experimental group with the highest level of total cholesterol, free cholesterol and phospholipids was the S-group. This group had as well levels of HDL-C and LDL-C significantly higher when compared with the remaining groups. The L-group had the lowest value of HDL-C. In spite of that, the index of artherogenicity (HDL/LDL+VLDL) was significantly higher in the L-group, followed by the O-, F- and S-group respectively. On the other hand, after 12 months adaptation we observed that the fatty acid composition of serum lipids clearly reflects the quality of the dietary fats. The O-group had significantly higher serum oleic acid levels than all the other groups, and its content in saturated fatty acids was the lowest. The same happens with red blood cell (Rbcs) membranes fatty acids but the effect is less marked. Membranes of the L-group were found to have the highest saturation index (SI) in Rbcs membranes, while the F-group had the highest unsaturation index (UI), followed by the O-group. Taken together, our findings show that the diet enriched in olive oil produces a lipid pattern intermediate between that obtained with the fish-oil-diet and the sunflower-oil-diet but with the advantage of Rbcs membranes with a lower amount of PUFAS. As it is known, membranes with high percentages of PUFAS are more accessible for peroxidation, and the degree of peroxidation of lipids is directly related with changes in the membranes functionality.

Long-term influence of dietary fat (sunflower oil, olive oil, lard and fish oil) in the serum fatty acid composition and in the different lipidic fractions, in miniature swine.

A total of 24 miniature swine (sus scrofa) was fed with four diets of 9% fat content, differing only in the quality of the fat source (sunflower oil, olive oil, lard fat and fish oil) for a 12 months period. After the experimental period, the influence of the dietary fat on the serum fatty acid composition, and the distribution of those fatty acids in the different serum lipidic fractions was studied. The olive oil group had the lowest SI value (total sum of saturated fatty acids) and the highest MUFA value (total sum of monounsaturated fatty acids) in serum. The sunflower group had higher proportions of n6 polyunsaturated fatty acids in serum, when compared with the remaining groups. The lard group and the fish oil group had both the highest values of SI and n3 polyunsaturated fatty acids. The results show that fatty acid composition in serum reflected, but not in all cases, the fatty acid composition of the diet. The highest correspondence was found with sunflower oil and olive oil diets. The existence of interactions between the different fatty acid series was evident, especially with the lard and the fish oil diets, as well as endogenous synthesis mechanisms. In lipidic fractions, higher correspondence with diet was found in EC fraction, but, as well as in serum, the existence of interactions between fatty acid series was evident, and especially activity and biosynthesis of desaturases may have been affected.

The influence of dietary fat source (sunflower oil or olive oil) on LDL composition and serum lipid levels in miniature swine (Sus scrofa).

A total of 24 miniature swine (Sus scrofa) were fed with two diets of 9% fat content, differing only in the quality of the fat source (sunflower oil and olive oil). Two groups of animals were fed for a 12-week period, and the other two groups were fed for a 50-week period. After the two experimental periods, the influence of the dietary fat on serum lipids and protein and fatty acid composition of isolated LDLs was studied. In the short term, the serum cholesterol level was slightly higher in the olive oil group but, with the time of adaptation to the diet, serum levels of TC, FC and PL increased significantly in the sunflower group. In the long term, LDL and HDL were also significantly higher in the sunflower group when compared to the monounsaturated diet. In the sunflower group, PROT/TC and PROT/LIP ratios decreased significantly with the experimental period, while in the olive oil group they increased, due to the decrease in EC and TG fractions. The LDL particle in the olive group contained fewer saturated fatty acids and more monounsaturated fatty acids, specially oleic acid, than the LDL in the sunflower group. The changes found in chemical and fatty acid compositions of LDL, according to the saturation degree of the predominant fat of the diet, could alter its cellular metabolism.