High-sulfate water consumption determines intake and metabolic responses to protein supplementation in lambs consuming low-quality forage.

Twenty Hampshire lambs (31 ± 4 kg BW) in individual metabolism cages were used in a 10-treatment by 2-period ( = 4) trial to evaluate the interaction between protein supplementation and sulfate water on intake and metabolic responses when lambs were fed low-quality grass hay (; 6.4% CP, 79.5% NDF). The treatment structure was a 2 × 5 factorial: 2 water qualities (WQ; low-sulfate [LS] and high-sulfate [HS]; 442 and 8,358 mg/kg total dissolved solids, respectively) and 5 soybean meal levels (SBM; 0%, 0.25%, 0.50%, 0.75%, and 1.00% BW/d). After 15 d of adaptation, periods consisted of 5 d for determination of forage and water intake, nitrogen balance, and digestion measurements (d 16 to 20) and 1 d for blood sampling and determination of ruminal hydrogen sulfide (HS) concentration (d 21). Supplemental SBM × WQ interactions were significant for forage OM intake ( = 0.04) and total OM intake ( = 0.04), whereas a tendency was observed for total tract digestible OM intake ( = 0.07). Intake values of LS lambs were higher than those of HS lambs ( < 0.05) in only the first and second levels of SBM. Water intake increased linearly ( < 0.01) with SBM level but was not affected by WQ ( = 0.39). Water quality and SBM supplementation affected total tract OM digestibility (TTOMD; < 0.01); LS lambs had lower TTOMD than HS lambs ( < 0.01). Plasma urea N increased linearly in response to SBM ( < 0.01) but was not affected by WQ ( = 0.11). Nitrogen balance was not affected by SBM × WQ interaction ( > 0.12), except for N utilization (N retained/N intake ratio; < 0.01). Regardless of WQ, N intake ( > 0.01), N urine ( > 0.01), and N balance increased linearly ( > 0.01) with SBM level. Water quality adversely affected N intake and N balance, although at the highest level of SBM no differences in N balance were observed between LS and HS lambs ( = 0.85). No changes due to WQ were observed for either urea reabsorbed by kidneys ( = 0.63) or glomerular filtration rate ( = 0.30), but renal function was affected by SBM level ( < 0.01). There was a supplemental SBM × WQ interaction for ruminal HS concentration ( < 0.01) due mainly to a greater concentration from 0.25% BW SBM in HS than in LS lambs. In conclusion, these results confirmed the existence of an interaction between sulfate water and supplemental protein, which alters intake and metabolic responses when lambs are fed low-quality grass hay.

Effect of peanut skin extract on chemical stability and sensory properties of salami during storage.

BACKGROUND: Peanut skin extracts (PSEs) have proven antioxidant properties in different food products. The objective of this study was to evaluate the effect of peanut skin extract as natural preserving compounds on chemical stability and sensory properties of salami during storage. RESULTS: PSE was obtained with ethanol-water and added during the preparation of salami samples. Raw salami samples were cured and stored at 15 °C and 65% relative humidity. Moisture, peroxide value, conjugated dienes, free fatty acids and sensory descriptive attributes were evaluated on the samples. Peroxide values increased during storage in all samples and were 82.9 in control (salami without additives), 18.0 in salami with 0.2 g kg(-1) PSE (E0.02), 13.0 in salami with 1.0 g kg(-1) PSE (E0.1), and 0.63 meqO2 kg(-1) in salami with butylated hydroxytoluene (BHT) after 42 days of storage. BHT and E0.1 treatments resulted in a lower increase in the intensity of oxidized flavor and a lower decrease in the intensity of salami flavor. CONCLUSION: Chemical indicators and descriptive results indicated that PSE retards lipid oxidation and preserves sensory properties of salami, prolonging its shelf life.

Beneficial effect of goat milk on bioavailability of copper, zinc and selenium in rats.

We studied the effects of dietary inclusion of freeze-dried goat and cow milk on the utilization of copper, zinc and selenium, and on the metabolic fate of copper and zinc, in rats using a standard (non-milk) control diet recommended by the American Institute of Nutrition and diets based on goat or cow milk. For animals given the goat milk diet, the apparent digestibility coefficient (ADC) of copper is similar to that obtained with the standard diet and higher than that in animals given the cow milk diet. The copper balance was higher among the rats given the goat milk and the standard diets than among those given cow milk. The ADC and retention of zinc and selenium were higher for the goat milk diet than for the other two diets. The copper content in the kidneys and in the femur was greater when the animals consumed a goat milk diet than a cow milk diet. Zn deposits in femur, testes, liver, kidney, heart and longissimus dorsi muscle were greatest with the goat-milk diet, followed by the standard diet and were lowest for the rats given cow-milk diet. This study shows that the goat-milk has an important and beneficial effect on the bioavailability of copper, zinc and selenium.

Digestive utilization of goat and cow milk fat in malabsorption syndrome.

We studied the effects of goat and cow milk fat on the digestive utilization of this nutrient and on some of the biochemical parameters that are related to the metabolisim of lipids, using rats with a resection of 50% of the distal small intestine and control animals (transected). The fat content in all the diets was 10% but the lipid quality was varied: the standard diet was based on olive oil, while the other two diets included fat obtained from lyophilized goat milk and cow milk, respectively. The digestive utilization of the fat was lower in the resected animals than in the transected ones for all three diets studied. In both resected and transected animals. the apparent digestibility coefficient (ADC) of the fat was greater with the standard diet (olive oil) than with diets whose fat content was provided by goat or cow milk. The digestive utilization of the fat was greater in the transected and resected rats receiving a diet of goat's milk (rich in medium-chain triglycerides) than those given a cow-milk-based diet and more closely approached the values obtained for olive oil. The consumption of goat milk reduced levels of cholesterol while levels of triglycerides, HDL, GOT and GPT remained with in the normal ranges, for both transected and resected animals. The advantageous effect of goat milk on the metabolisim of lipids with respect to cow milk suggests that the former should be included in the diet in eases of malabsorption snydrome.

Beneficial effect of pollen and/or propolis on the metabolism of iron, calcium, phosphorus, and magnesium in rats with nutritional ferropenic anemia.

There has been considerable debate regarding the nutritional benefits of pollen and the propolis produced by bees, although most contributions have lacked scientific soundness. This paper describes the possible beneficial effect of their use in pharmacological products in cases of anemic syndrome. We studied the effect of these two natural products on the digestive utilization of iron, calcium, phosphorus, and magnesium, using control rats and rats with nutritional ferropenic anemia. The addition of these products to the diet produced a positive effect on weight gain; this fact could constitute a scientific basis for the application of pollen and propolis as fortifiers. They improve the digestive utilization of iron and the regeneration efficiency of hemoglobin, especially during recovery from an anemic syndrome. They also have a positive effect on phosphocalcic metabolism and maintain an appropiate level of magnesium metabolism. Furthermore, in iron-deficient rats, these natural products palliate, to a large extent, the adverse effects of iron deficiency on calcium and magnesium metabolism as a result of the improvement in the digestive utilization of these minerals.

Effect of processing methods on the calcium, phosphorus, and phytic acid contents and nutritive utilization of chickpea (Cicer arietinum L.).

The effect of chickpea (Cicer arietinum L.) processing methods on the nutritive utilization of calcium and phosphorus and on phytic acid, a seed component that affects mineral utilization, was studied. Chemical and biological methods were used for nutritional determinations in growing rats. The digestive utilization of calcium from raw chickpea was adequate for growing rats; however, processing resulted in a slight decrease. The metabolic utilization of chickpea calcium was low because of the low rates of net absorption. This was reflected in the decreased calcium levels in longissimus dorsi muscle in the absence of mobilization of calcium from the femur. Soaking in acid solution followed by cooking decreased phytic acid content, suggesting that processing made part of the phytic acid phosphorus available. The absorbed phosphorus was greater than the nonphytic phosphorus supplied by the diet. The digestive utilization of phosphorus was similar in processed and raw chickpeas, despite the loss of soluble anion as a result of processing. These results may indicate the contribution of phosphorus in the form of inositol hexaphosphate-phosphorus.

Alpha-lipoic acid prevents 3,4-methylenedioxy-methamphetamine (MDMA)-induced neurotoxicity.

A single administration of 3,4-methylenedioxymethamphetamine (MDMA, 20 mg/kg, i.p.), induced significant hyperthermia in rats and reduced 5-hydroxytryptamine (5-HT) content and [3H]paroxetine-labeled 5-HT transporter density in the frontal cortex, striatum and hippocampus by 40-60% 1 week later. MDMA treatment also increased glial fibrillary acidic protein (GFAP) immunoreactivity in the hippocampus. Repeated administration of the metabolic antioxidant alpha-lipoic acid (100 mg/kg, i.p., b.i.d. for 2 consecutive days) 30 min prior to MDMA did not prevent the acute hyperthermia induced by the drug; however, it fully prevented the serotonergic deficits and the changes in the glial response induced by MDMA. These results further support the hypothesis that free radical formation is responsible for MDMA-induced neurotoxicity.

Interactions among iron, calcium, phosphorus and magnesium in the nutritionally iron-deficient rat.

We studied the development of nutritional iron deficiency 0, 10, 20, 30 and 40 days after the intake of a semisynthetic diet lacking iron (diet 0) and the possible interactions with calcium, phosphorus and magnesium in both control rats and rats after 40 days of iron deficiency. During this period, iron deficiency was found to produce stress in the rats, as evidenced by high levels of cortisol in the serum. High levels of parathyroid hormone (PTH) were also found. There was a considerable increase in the absorption of calcium, phosphorus and magnesium, but the phosphorus and magnesium balance decreased and that of calcium remained practically unchanged, although there was an increase in calcium urinary elimination. Despite the noticeable degree of bone demineralization, which was evident in the femur, serum levels of calcium, phosphorus and magnesium remained constant. The present study shows that severe nutritional ferropenic anaemia provokes significant alterations in the metabolism of calcium, phosphorus and magnesium. We conclude that these alterations should be taken into account in the treatment of this pathology, given its prevalence and the fact that it may exacerbate other pathologies, particularly those related to the metabolism of calcium and phosphorus.

Effect of source of iron on duodenal absorption of iron, calcium, phosphorous, magnesium, copper and zinc in rats with ferropoenic anaemia.

We studied the effects of iron deficiency on the in vivo absorption (by using the intestinal perfusion technique in the duodenum) of different dietary sources of iron (haem, non-haem and equal parts of both forms) and investigated the interactions between iron and calcium, phosphorous, magnesium, copper and zinc in control and iron-deficient rats. Three perfusion solutions containing a different source of iron were used: solution 1, ferric citrate; solution 2, haemoglobin; solution 3, equal parts of ferric citrate and haemoglobin. We also tested the same perfusion solution with 2,4-dinitrophenol (2,4-DNP), an inhibitor or oxidative phosphorylation (solutions 1-I, 2-I and 3-I). In control rats we observed three mechanisms of iron absorption: passive for soluble iron salts, active receptor-mediated for non-haem iron complexes, and active receptor-mediated for haem iron. In anaemic rats iron absorption was greater than in controls, except after perfusion with solution 2 (containing haemoglobin). Absorption increased as a result of both the passive and active, receptor-mediated mechanism for non-haem iron complexes. The active component was influenced by the depletion of haem receptors under severe iron deficiency. The absorption of calcium, copper and zinc in iron-deficient animals was lower than in controls, whereas phosphorus and magnesium absorption were not significantly affected. After perfusion with solution 2 or 3, calcium, copper and zinc absorption were lower than after solution 1. We conclude that ferropoenic anaemia in the rat impairs the absorptive process of those minerals that are absorbed, at the duodenal level mainly via active transport (haem iron, calcium, copper and zinc), but does not affect the active component involved in non-haem iron absorption.

Calcium absorption in rats with distal intestinal resection: influence of type of dietary fat, cholecalciferol and nature of the adaptative response.

The effects of dietary fat and supplementation with cholecalciferol on calcium absorption at different luminal concentrations (2.07 mmol/l and 2.07 mmol/l with 0.5 mmol/l 2,4-dinitrophenol and 8.20 mmol/l) were studied in vivo in the perfused duodenum, residual jejunum and proximal colon of rats with resection of 50% of the distal small intestine, as well as the nature of the adaptative response (passive or active). Changing the source of dietary fat (diet B, containing 1/3 medium chain triglycerides, 1/3 olive oil, 1/3 sunflower oil) increased calcium absorption, preferentially via active transport, in both transected and resected rats. Supplementation of diet B with cholecalciferol further enhanced intestinal calcium absorption, especially in the colon. These results suggest the importance of diet in the adaptive processes and confirm that active mechanisms of transport adapt more readily to intestinal resection than do passive mechanisms.

Effects of iron replenishment on iron, calcium, phosphorus and magnesium metabolism in iron-deficient rats.

We investigated the effect of Fe deficiency on the nutritive utilization of Fe, Ca, P and Mg in rats. Aside from the well known depletion of Fe in liver, femur and sternum with low values of Hb, Fe deficiency impaired Ca, P and Mg metabolism at different degrees. Iron deficiency altered Mg absorption, lowered the concentration of Ca in the liver, femur and sternum, raised the concentration of P and Mg in the liver, and decreased P in the femur. The altered status was not completely rectified by iron supplementation as the animals were still slightly anemic at the end of the study. The second purpose of the study was to evaluate the ability of three iron compounds (ferric citrate, ferrous sulfate and ferrous ascorbate) to correct the undesirable effects of Fe deficiency. Ten days after treatment with these diets, Fe-deficient rats still had reduced Mg absorption, especially those fed ferric citrate. The concentrations of hemoglobin approached normal values in all groups; however, serum Fe remained low, indicating that Fe reserves were still depleted. Hepatic and femoral Fe concentrations were also lower in all Fe-deficient groups regardless of the diet given, compared with their respective controls, whereas Fe concentrations in the sternum increased significantly with all three diets, suggesting an increase in erythropoiesis. The concentration of Ca, P and Mg in liver approached normal values, and appeared to normalize in the femur, except that Ca and P concentrations remained low with the citrate diet. In the sternum, a site assumed to have higher requirements for these minerals, the concentrations of Ca, P and Mg also increased. These findings indicate that Fe is involved in the bone mineralization, and that in physiological terms, Fe interacts favorably with Ca, P and Mg metabolism, since Fe deficiency altered the status of these metals. These findings also suggest that ferrous ascorbate and ferrous sulfate were more effectively absorbed than was ferric citrate.

Supplementation of a cereal-milk formula with haem iron palliates the adverse effects of iron deficiency on calcium and magnesium metabolism in rats.

Aside from the well known alteration of Fe status in Fe deficiency, this condition has also a negative effect on the bioavailability of Ca and Mg. We studied the influence of the supplementation of a commercial cereal-milk formula with bovine blood on Fe, Ca, P, and Mg metabolism in control and Fe-deficient rats to investigate whether high Fe levels in diet produce some interactions and the possibility of decreasing these latter by a haem-Fe supplementation. The bioavailability in control and Fe-deficient animals was determined as the apparent digestibility coefficient and hemoglobin regeneration efficiency, both of which are accurate estimations of total Fe utilization. Non-fortified cereal-milk formula decreased the apparent digestibility coefficient of Ca and Mg in Fe-deficient rats; the concentrations of these minerals in liver, femur, and sternum were lower than in control animals. However, when the Fe content of the cereal-milk formula was doubled by supplementation with bovine blood, the adverse effects on the digestive utilization of Ca, and especially of Mg, were palliated, the concentration of these two minerals in the organs investigated increased, and the overall Fe status improved in Fe-deficient rats.

Effects of intestinal resection, cholecalciferol and ascorbic acid on iron metabolism in rats.

The effect of dietary supplementation with ascorbic acid or cholecalciferol on Fe utilization was studied using the metabolic balance technique, in rats in which 50% of the distal small intestine was removed, or in which the mid small intestine was transected and reanastomosed (controls). Three different diets were used. The first (basal diet) contained (g/kg dry wt): protein (casein + 50 mg D,L-methionine/g) 120 and fat (medium-chain triacylglycerols, olive oil and sunflower oil, in equal parts) 40. The other diets were obtained by adding ascorbic acid (150 mg/kg diet) or cholecalciferol (0.4 mg/kg diet) to the basal diet. Apparent digestibility coefficient (ADC) and Fe retention were significantly lower in resected animals than in their respective control groups (transected rats). However, the addition of ascorbic acid or cholecalciferol to the basal diet increased the ADC and Fe retention in both transected and resected rats. Five weeks after surgery, resection also resulted in a reduced concentration of Fe in the sternum, but did not reduce the concentration of haemoglobin or serum Fe total Fe-binding capacity or the concentration of Fe in liver, testes, femur or muscle (longissimus dorsi). Supplementation with ascorbic acid increased serum Fe concentration, while the concentration of Fe in muscle was reduced by supplementation with both ascorbic acid and cholecalciferol. Neither supplementation had any effect on the Fe concentration in other tissues, on haemoglobin concentration or plasma total Fe-binding capacity. Thus, supplementation with ascorbic acid or with cholecalciferol increased Fe absorption and reduced the concentration of Fe in muscle.

Copper malabsorption after intestinal resection in rats. Effects of cholecalciferol and ascorbic acid.

Dietary modifications can partly compensate for the alterations in copper homeostasis caused by distal intestinal resection, by improving biliary function. We studied the effects of resecting 50% of the distal small intestine (DSI) on copper status in rats fed three semisynthetic diets (basal diet, and basal diet with cholecalciferol or ascorbic acid). Intestinal resection significantly decreased the digestive (apparent digestibility coefficient; ADC) and metabolic utilization (balance) of copper 1 month after surgery. However, the supplementation of the basal diet with cholecalciferol attenuated the negative impact of surgery, leading to small differences in Cu ADC and Cu balance between transected and resected rats. Ascorbic acid also enhanced copper retention. Copper status was not as markedly affected by intestinal resection as digestive utilization 1 month after the operation. The beneficial effects of cholecalciferol and ascorbic acid at the digestive and metabolic levels suggest ways to lessen the impact of intestinal resection, and to avoid possible long-term postabsorptive alterations in copper distribution.

Effects of type of dietary fat and cholecalciferol on magnesium absorption in rats with intestinal resection.

We studied the effect of type of dietary fat and supplementation with cholecalciferol on magnesium absorption in the duodenum, jejunum and proximal colon in rats with resection of 50% of the distal small intestine. Magnesium transport against the concentration gradient was found to occur in all three intestinal segments, although transport increased significantly only in the proximal colon of intestinally resected rats fed a diet supplemented with cholecalciferol at a rate of 0.425 mg/kg diet and mixture of equal parts of medium chain triglycerides, sunflower oil and olive oil as the source of dietary fat (diet B), in comparison with magnesium absorption in control rats subjected to intestinal transection and fed diet B, and in resected rats fed a diet without cholecalciferol supplementation and in which olive oil was the sole source of dietary fat (diet A). Magnesium absorption due to active and passive transport together, was greater in resected than in transected rats in all three intestinal segments, although the difference was significant only in the jejunum (the segment closest to the anastomosis), because of the greater increase in mucosal mass in resected animals. When the three intestinal segments were compared, magnesium absorption in favour of and against the concentration gradient in the proximal colon was significantly greater than in the duodenum or the jejunum, in resected and transected animals fed diet A or diet B. These findings show that the colon is the segment that most efficiently absorbs magnesium in rats with intestinal resection, especially when diet B is given.

Effect of intestinal resection, type of dietary fat and time on biliary lipid secretion in rats.

The effects of time and the type of dietary fat on biliary physiology in rats with 50% resection of the distal small intestine were investigated. The effects of ursodeoxycholic acid as an exogenous source of bile acid added to the diet were also studied. The fat composition of all diets was the same in quantitative terms (4%), and differed only in the type of lipid supplied: olive oil (diet A) or one-third medium chain triglycerides, one-third sunflower seed oil and one-third olive oil (diet B). In resected rats given diet A for 1 or 3 months, there was a decrease in biliary secretion of cholesterol and phospholipids, and in the lithogenic index, with respect to the control group. Resected rats fed diet B for 1 or 3 months showed increases in biliary secretion of cholesterol and phospholipids, and in the lithogenic index, in comparison with resected rats fed diet A. The addition of ursodeoxycholic acid to diet B led to the decoupling of bile acid and bile lipid secretion.

Influence of dietary fat components and intestinal resection on iron, zinc and copper metabolism in rats.

The effect of resecting 50% of the distal small intestine (DSI) on iron, zinc and copper nutritive utilization was studied in rats fed two different types of diet: a standard diet containing 4% olive oil (A) and a diet containing different sources of fat (1/3 olive oil, 1/3 sunflower oil and 1/3 medium chain triglycerides) (B). One month and 7 days after surgery, intestinal resection led to a deterioration in digestive (ADC) and metabolic (balance) utilization of iron, zinc and copper. To assess trace metal postresectional homeostasis, we also measured these mineral concentrations in whole blood, plasma and several organs (liver, femur, sternum, longissimus dorsi muscle and testes). Our findings showed no significant differences in iron, zinc and copper concentrations between the organs, suggesting that the observed decrease in digestive and metabolic efficiency of these minerals was not markedly reflected at the postabsorptive level, since the distribution of the trace elements in the whole organism remained unchanged. We conclude that one month and 7 days after this surgical intervention, adaptive mechanisms are well developed in resected rats fed a diet with an adequate mineral supplement.

Effect of iron deficiency on the digestive utilization of iron, phosphorus, calcium and magnesium in rats.

The influence of the source of dietary Fe (ferric citrate alone or mixed with bovine blood at a proportion of 1:1 (v/v)) on the digestive utilization of Fe, P, Ca and Mg, and on haemoglobin regeneration efficiency (HRE) was investigated in control and Fe-deficient rats. Diet A contained (by analysis) 43.5 mg Fe/kg diet (as ferric citrate), and diet B contained 44.3 mg Fe/kg diet (ferric citrate-bovine blood). In Fe-deficient rats fed on diet A or B the apparent digestibility coefficient (ADC) of Fe increased by 42.3 and 45.7% respectively. The ADC of Ca and Mg decreased significantly in Fe-deficient rats regardless of the source of dietary Fe. The HRE increased by 72.9% in Fe-deficient rats fed on diet A, and by 91.1% in Fe-deficient animals fed on diet B. In Fe-deficient rats fed on Fe for 10 d the values of haematological variables approached normality. However, serum Fe remained low, indicating that Fe reserves were still depleted. A deficient dietary supply of Fe for 30 d did not significantly modify the numbers of circulating leucocytes.

Influence of intestinal resection and type of diet on digestive utilization and metabolism of magnesium in rats.

The influence of intestinal resection and type of diet on nutritive utilization of magnesium was studied in rats in which 50% of the distal small intestine was removed and in sham-operated controls. Nutritive parameters were analyzed after feeding the rats different diets for one or three months after surgery. Loss of 50% of the distal small intestine reduced digestive utilization of Mg as reflected in the mineral content of bone, however digestive and metabolic utilization of Mg were seen to recover by three months postsurgery. When dietary fat was supplied as equal parts of medium chain triglycerides, sunflower seed oil and olive oil instead of 100% olive oil, Mg absorption and retention were enhanced in resected rats after one month with the beneficial effects on Mg metabolism becoming even more marked after three months. One month after resection, dietary supplementation with vitamin D3 clearly stimulated digestive utilization of Mg. Although this effect was less notable at three months, nutritive utilization of Mg remained higher than in resected rats fed a diet lacking vitamin D3 supplementation. Dietary levels of vitamin D3 favored the deposition of Mg in bone tissue.

[The effect of intestinal resection and dietary fat quality on the nutritional utilization of fat]. / Influencia de la resección intestinal y de la calidad lipídica de la dieta sobre la utilización nutritiva de la grasa.

The influence of the quality of dietary fat on digestive and metabolic utilization of fat, serum levels of cholesterol and triglycerides and the relative percentages of serum fatty acids was studied in rats in which 50% of the distal small intestine (DSI) was resected and in sham-operated controls. Nutritive parameters were measured 1 month after surgery. The fat components of the diets were: olive oil, butter and equal parts of medium chain triglycerides (MCT), olive oil and sunflower seed oil. There was no changes in digestive utilization of fat in shamoperated controls with either dietary sources of fat, olive oil or butter. The removal of 50% of the distal small intestine led to a decline in the digestive utilization of fat (ADC) in both test diets. When dietary fat was supplied as equal parts of MCT, olive oil and sunflower seed oil instead of 100% olive oil (diet C), digestive utilization of fat was enhanced in resected rats. When ursodeoxycholic acid (UDCA) was added to diet C, digestive utilization of fat remained high, reaching values as elevated as those in sham-operated controls. At the metabolic level, resection of half the DSI led to a significant decrease in serum triglycerides and cholesterol levels, independently of type of dietary fat tested. The type of diet, as well as intestinal resection, do not led to an essential fatty acid deficiency in serum lipids; it is only a reflect of the supplemented diet fat contents.