Effect of inulin and oligofructose enrichment of the diet on rats suffering thiamine deficiency.

Thiamine deficiency resulted in inhibition of two main pathways supplying energy to the tissues: glycolysis and ß-oxidation. Glycolysis was found to be inhibited to 40% of initial value calculated on the basis of RBC trans-membrane transport of glucose. Prolongation of experiment cause lowering of uptake of this sugar. In rats, energy production from fatty acids (FA) seems to be less sensitive to thiamine deficiency than glycolysis. After 30 days of feeding, utilization of FA in rats was depressed to the 61% of initial value. Thiamine deficiency suppressed insulin secretion, and the changes were statistically significant. Feeding of rats with thiamine restricted diet for 1 month caused the reduction of serum insulin by 14%. In the same animals, trans-membrane glucose transport was reduced over two-times, what might suggest a decreased efficiency of insulin action in such conditions. The kind and concentration of non-digestible fructo-oligosaccharides (FOS) did not affect significantly serum insulin concentration in animals fed thiamine restricted diet. Substitution of a part of wheat starch with FOS has only insignificant compensatory effect on the uptake of glucose. A partial amelioration of the ß-oxidation inhibition caused by feeding rats with thiamine deficient diet was observed in animals supplemented with FOS. However, this effect was statistically significant only in rats receiving diet containing 10% of inulin. The effect of supplemented FOS and their concentration on trans-membrane glucose transport in RBC was statistically significant, when pulled supplementation groups were used for statistical evaluation.

The influence of alpha-tocopherol supplementation on plasma concentration of this vitamin and insulin in sedentary or physically trained rats.

Male young growing rats of Wistar strain (n = 54) were fed a vitamin E deficient diet for 3 days of adaptation period and then 10 days of experimental period. After adaptation half of the rats ran, once per a day, on a treadmill with a rate of 2.0 m/s for 15 minutes for the following 10 days. Animals were given orally 0, 0.5, 1.0 or 4.0 mg/d/rat of alpha-tocopherol. The aim of the study was to evaluate the influence of physical training on tocopherol and insulin concentrations in the blood plasma of rats treated with different doses of vitamin E. The concentrations of alpha-tocopherol (HPLC-UV method used) and insulin (rat insulin specific RIA method used) were estimated in the blood plasma. Lower concentration of vitamin E in physically trained animals was observed, which may suggest increased needs of organisms for antioxidants, as a result of increased free radical production. In trained rats a lower concentration of plasma insulin was also observed. This effect is probably related to improvement in insulin action observed in organisms under physical exercise. The most significant impact on plasma alpha-tocopherol was due to its supplementation level. The treatment of rats with different doses of alpha-tocopherol was found to be not related to insulin concentration in plasma. A significant increase in feed conversion factor was noted in vitamin E treated animals. The obtained results suggest that the increased requirement of trained rats for antioxidants might be covered by alpha-tocopherol supplementation.

The influence of dietary vitamin A supplementation on vitamin A and insulin levels in sedentary or physically trained rats.

Male rats of Wistar strain (n = 48) were fed a vitamin A deficient diet for 3 days of adaptation period and then a 10 day experimental period to reduce slightly the body stores of this vitamin. Half of the animals were subjected to physical training and/or oral vitamin A supplementation. Four different doses of supplementation were used--0, 7.5, 15 and 60 microg/d/rat, which is equivalent to 0, 25, 50 and 200 IU of vitamin A, respectively. Animals from the defined groups ran on a treadmill with a rate of 2.0 m/s for 15 minutes per day for 10 days. After overnight fasting, the rats were sacrificed, and insulin in blood serum and hepatic retinol concentrations were estimated. Daily feed intake and daily body gains were similar in groups of sedentary and physically trained rats. A moderate level of oral vitamin A supplementation (the highest supplemented dose was about 6 x the above recommended NRC level) did not cause any changes in these zootechnical parameters. Oral Vitamin A supplementation resulted in an increase in retinol concentration in the liver (F = 15.2, p < 0.001), but without significant difference between trained and untrained animals. Physical training of rats caused a statistically significant decrease of insulin concentration in blood serum (1.53 +/- 0.18 vs. 1.73 +/- 0.20). This difference was highly significant (F = 11.1, p < 0.001). Vitamin A supplementation was found not to influence the concentration of this hormone, which is responsible for energy metabolism regulation in the body. Based on estimated parameters, the necessity of vitamin A excessive use in physically trained subjects was not proven.

The influence of folic acid, vitamins B(2) and B(6) supplementation on feed intake, body and organs weight, and liver fatty acids composition of rats subjected to 3 months moderate protein deprivation.

This study was conducted to determine the effect of a 3-month dietary protein restriction - protein provided 9% of energy (20% in control group). In this dietary restriction folic acid, vitamins B(2) and B(6) were delivered in amount three times above the standard level. It was observed that animals fed a protein restricted (PR) diet weighed about 5% less than animals consuming adequate diet, but the difference was not statistically significant. Enrichment of PR diet with vitamin B or folic acid caused tendency to further suppression of weight gain, and in case of vitamin B(6) these differences were statistically significant. However, such body weight (BW) suppression was not observed when all studied vitamins were used together. Significant reductions in relative liver weight (vitamin B(2) addition), the heart (folic acid) and the lungs (vitamin B(6)) were observed. The PR diet, when all vitamins were added together, caused a decrease in weights of the lungs, heart and liver scaled to BW of rats, simultaneously with a significant increase in testis weight. Feed intake and feed conversion ratio were higher in animals given PR diet without a significant influence of vitamin supplementation (except vitamin B(6) causing further increase in feed conversion ratio). Hepatic fatty acids composition of rats was not affected by protein restriction, as well as by single vitamin supplementation. However, dietary supplementation of all examined vitamins together caused a decrease in monounsaturated fatty acids followed by an increase in polyunsaturated fatty acids participation in total fatty acids pool. It seems that enrichment of PR diet with a mixture of folic acid, vitamins B(2) and B(6) resulted in a partial reverse of growth suppression and reduction in testis size in rats.

Influence of folic acid, vitamin B2 and B6 supplementation on feed intake, body and organs weight, and liver fatty acids composition in rats subjected to severe protein deprivation.

Growing rats fed for 3 months a low-protein (LP) diet (4.5% of energy from protein), possessed about 29% lower body weight than animals consuming adequate-protein diet (20% energy from protein). The LP diet feeding caused an increase in daily feed intake followed by a decrease in feed conversion efficiency. The enrichment of LP diet with folic acid, vitamin B2 and B6 (3 times above the level applied in the control diet) did not have any impact on rats BW and supplementation with these vitamins minimize the effect of LP diet on feed intake. The use of examined vitamins had a tendency to diminish an increase in feed conversion ratio caused by the LP nutrition. This effect was significant when all vitamins were added together. Rats fed the LP diet had higher relative weights of lungs, heart, liver and testis. Vitamins enriching the LP diet were observed to decrease a relative weight of lungs (folic acid, vitamin B6 and vitamin mixture), and liver (vitamin B6 and vitamin mixture). A tendency of increasing relative testis weight was also revealed in rats given the LP diet enriched with vitamins. The lower content of hepatic polyunsaturated fatty acids (FA) and a tendency for monounsaturated FA content to be higher were found in rats fed the LP diet. The LP diet enrichment with folic acid caused that these changes were more pronounced and statistically significant. Enrichment of LP diet with vitamins tested may cause a partial reverse of changes observed in the hepatic FA composition.

Quantitative study of soybean-induced changes in proliferation and programmed cell death in the intestinal mucosa of young rats.

The use of soybean in human and animal nutrition is limited because of high content of bioactive compounds: enzyme inhibitors, polyphenols, goitrogens, phytates, saponins, sugars, and agglutinins. The damage of intestinal mucosa structure was previously observed in animals fed soybean supplemented diets. Hence, the objectives of the presented study were to compare intensity of epithelium remodeling processes in different intestinal segments, and to evaluate the influence of the 1% of soybean dietary supplementation on the processes in intestinal mucosa. The experiment was performed on 30 Wistar rats fed AIN-93 based diets. Animals were divided randomly into three groups: control (CTRL), with 1% of raw soybean (RS) and with 1% of soaked and boiled soybean (BS). The samples of: duodenum (DUO), proximal jejunum (PROX), mid-jejunum (MID), distal-jejunum (DIST) and ileum (ILE) were collected. The following processes in these samples were evaluated: mitosis (Ki-67), apoptosis (Cpp32), autophagy (MAP I LC3) and DNA damage (p53). Present data show that modification of soybean by soaking and subsequent boiling markedly influences the enterocyte turnover in the small intestine mucosa. Increased mitotic ratio in the intestine of rats fed with boiled soybean masks the negative effects of soybean on the small intestine structure.

Effect of dietary protein level and source on bone mineralization in rats.

Bone mineralization was studied in rats. Animals were divided into three feeding groups: LCP - diet with 13.5% crude protein in DM (5% of gluten, 10% of casein), HCP - diet with 21.2% CP in DM (8% of gluten, 10% of casein), and LSM - diet based on grain meals and meat-bone meal (21% CP in DM). After 28 days feeding, animals were euthanased by cervical dislocation and femur bones were collected, weighed and kept frozen until analyses. Diets with 21% protein (HCP, LSM) significantly increased weight of femur bones. Despite of the substantially higher ash level (7.1%) in the LSM diet than in the LCP diet (3.4%), rats of both groups had the similar bone concentration of Ca (15.7 +/- 1.1 vs. 17.4 +/- 1.1 g/kg) and Zn (178.7 +/- 7.9 vs. 173.0 +/- 8.5 mg/kg). However bone density in LSM rats was significantly higher than in LCP ones. Although rats fed HCP diet had intermediate bone density, the bone concentration of Ca (11.4 +/- 0.5 g/kg) and Zn (145.1 +/- 2.9 mg/kg) was significantly lower, than in animals fed LCP and LSM diets. This was related to the very wide protein/calcium (37:1 g/g) and protein/zinc (5.3:1 g/mg) ratios in HCP diet. Those ratios were narrowest in the LSM diet: 16.2:1 (CP/Ca) and 2.6:1 (CP/Zn). It can be conluded that protein/mineral ratio in a diet is a very important factor in bone development, besides dietary protein and ash contents itselves.

Diets containing leguminous seeds influence chromium content in the rat femur bone.

Leguminous seeds contain a lot of antinutritional factors (ANFs) such as protease inhibitors, lectins and condensed tannins which can affect bioavailability of nutrients. Detrimental effect of protease inhibitors can be decreased by sulphur amino acids addition. Moreover, most of the leguminous ANFs are thermolabile. Hence, legumes tested in our study were extruded and/or diets were supplemented with methionine and cystine (0.15% + 0.15%). The present experiment was performed for 28 days on 90 Wistar rats divided into nine feeding groups. Semipurified diets (10% casein) were supplemented (10%), except the control one, with soybean (S) or faba bean (F), raw (R) or extruded (E), with addition of sulphur amino acids (SAA) or without them. The Cr concentration was determined in the femur bone. Total feed intake during whole trial widely varied among the groups and was the lowest in SR (289 g) and FR (294 g) groups. There was no correlation between feed intake and Cr content in the femur bone. Generally, 10% soybean in the diet decreased Cr concentration in the bones, and faba bean increased it. The SAA addition to diets generally increased femur Cr content. However, there was a significant interaction between SAA supplementation and extrusion of faba bean, hence, the effect of their combination was unclear.

The influence of dietary sulphur loading on metabolism and health in young sheep fed low fibre and high starch diet.

The purpose of the experiment was to evaluate the long-term effect of a low roughage diet (7-8% CF) with or without sulphur (S) supplementation (elemental and sodium sulphate 1:1) on basal dietary components, Zn, Cu and S availability, rumen metabolism and health in growing sheep. The control diet contained 0.2% and the supplemented diet 0.8% of S on a DM basis. The experiment lasted 12 weeks. The intake of the diet with 0.8% of S resulted in an increase in rumen acetic acid concentration. Rumen lactic acid concentrations in S-supplemented versus control sheep were higher in the first and lower in the third month, and decreased at the end of the third month of the experiment in both groups. Blood plasma pyruvate was lower at the end of the experiment in S-supplemented sheep than in control sheep. In the 5th week of the experiment, the high S diet depressed basal nutritional components as well as Zn and Cu availability. After 12 weeks of feeding of this diet, polioencephalomalacia had developed in all sheep.

Rumen dry matter and crude protein degradability of extracted or untreated oilseeds and Leucaena leucocephala leaves.

A study was undertaken to determine the rumen DM and CP degradability characteristics of soyabean, canola seed, peanut, palm kernel and Leucaena leucocephala leaves. The oilseeds were either treated with n-hexane to extract the fat or left untreated. Nylon bags were incubated in each of four rumen cannulated sheep for 0, 2, 4, 6, 12, 24 and 48 h. Animals were fed on a diet consisting of meadow hay (ad libitum) and 150 g of concentrate twice daily. Fat extraction caused a decrease (P < or = 0.05) in DM disappearance of soyabean at 0, 2, 4, 6 and 12 h and of peanuts at all incubation times. CP disappearance from peanuts was reduced (P < or = 0.05) as a result of fat extraction at 0, 2, 4, 6 and 12 h. Fat extraction of canola seed increased CP disappearance at 0, 2, 4, 6 and 24 h (P < or = 0.05). However, in the case of defatted canola seed, an increase in DM disappearance (P < or = 0.05) was observed in the first 4 incubation times and a decrease (P < or = 0.05) in the later times. Fat extraction increased (P < or = 0.05) DM disappearance of palm kernel at 0 and 48 h, but reduced it at 4, 6 and 24 h. CP disappearance of palm kernel was improved by treatment (P < or = 0.05) at 0, 4, 24 and 48 h and decreased at 12 h. In the case of palm kernel the largest differences in DM and CP disappearance occurred between the 24 and 48 h incubation times. Degradability characteristics for DM and CP of full-fat soyabean, canola seed and peanut were comparable to those of the full fat samples. Effective DM degradability of soyabean, canola seed and peanuts was 72.2 and 71.9; 74.1 and 66.8; and 85.9 and 70.8 for full fat and extracted feeds, respectively. Effective CP degradability was similar in all oilseeds with the exception of the extracted canola seed. Therefore, the incorporation of full-fat soyabean, canola seed and peanut into ruminant rations can be considered as a means of increasing the energy balance. Both palm kernel DM and CP degradabilities were characterized by slow rates of degradation by negative values "b". This suggests the predominance of microbial colonization over disappearance during incubation. DM and CP disappearance of Leucaena leucocephala leaves originating from Cuba were lower than those from Nigeria. Degradability characteristics for CP and DM of Cuban leucaena leaves showed that the linear model resulted in a better fit than the exponential one.

Comparison of the influence of dietary fibre sources with different proportions of soluble and insoluble fibre on Ca, Mg, Fe, Zn, Mn and Cu apparent absorption in rats.

The 6 week experiment was performed on growing Wistar male rats. In the third and the sixth weeks digestibility trials were performed. The following high fibre preparations were supplemented to the control diet (C): high methoxylated citrus pectin (Cr); apple pomace (A), potato fiber "Povex" (P) and sugar beet pulp (B). Fibre supplementation, except Cr, significantly increased Ca, Mg, Fe, Mn, Zn, Cu excretion in faeces and decreased their apparent absorption in both trials. Significant correlations (P < or = 0.001) were found between crude, insoluble and total fibre intake and mineral excretion and apparent absorption. Apparent absorption of minerals increased from the third to the sixth week in group C and in group Cr, except Fe, while it decreased in groups P and B or showed tendency to decrease. In the sixth week the following differences (P < or = 0.05) in apparent absorption were observed between diets, in descending order: [equation: see text]

Rumen degradability of dry matter and crude fibre of irradiated and sodium hydroxide treated straws.

Wheat straw (WS) and triticale straw (TS) were treated with 2- and 4%-NaOH and/or 300- and 600-kGy radiation doses (accelerated electrons) for improvement of the nutritional value of these feeds. Beside the chemical composition of straws, the nylon bag rumen disappearance of dry matter and crude fibre was estimated. NaOH did not influence the chemical composition of straws, while irradiation significantly reduced the level of crude fibre (CF), neutral detergent fibre (NDF) and acid detergent fibre (ADF) proportionally to the dose. The level of nitrogen free extractives (NFE) and alpha-linked glucose polymers pronouncedly increased in the radiated straws. NaOH treatment raised potential rumen degradability of DM and irradiation did so in the case of potential as well as effective degradability. It was not able to prove the summarized influence of both treatments on DM and CF rumen degradability of the straws. The dynamics of the rumen disappearance of DM was different in the straws.