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Background: Maillard reaction products (MRP) improve food palatability and are linked to some positive biological actions. However, diverse negative consequences, some related to protein damage and mineral availability, have been established., Aim of Study: We investigated the effects of MRP, from a bread crust diet, on phosphorus bioavailability and tissue distribution in rats to determine whether these effects are related to the molecular weight of browning products., Methods: During a study period of 88 days, rats were fed either a control diet or one of the following: with bread crust as a source of MRP, or one with its soluble high molecular weight, soluble low molecular weight or insoluble fraction (bread crust, HMW, LMW and insoluble diets, respectively). In the final week, a phosphorus balance was performed, after which the animals were sacrificed and some organs removed to analyse phosphorus content. A second balance was carried out throughout the experimental period to calculate phosphorus retention., Results: Phosphorus balance in the last week was unchanged. However, considering the whole experimental period, a trend towards improved bioavailability, significant in the HMW group, was observed. Higher phosphorus concentrations were measured in the small intestine and bone., Conclusions: The consumption of MRP derived from bread did not alter phosphorus retention, due to increased bioavailability, especially concerning HMW compounds. The overall phosphorus body content remained unchanged and there were no changes in the bone, its principal metabolic destination. However, MRP consumption markedly raised phosphorus levels at the digestive level, especially when consumed as isolate fractions. The slower rate of stomach emptying is assumed to be related to this effect.

It was studied the levels of phosphorus in serum and urine in two groups of pregnant women. One group was advised to follow their usual intake and the other to supplement the diet with 750 ml of milk. A control group of healthy non pregnant women were conformed to the same protocol. Pregnant women that followed their usual intake had the same levels of serum phosphorus and maximum phosphate transport as controls. Pregnant women who had taken milk supplement showed in the second and third trimester of pregnancy significantly lower serum phosphorus and maximum phosphate transport levels than controls and also with respect to pregnant women in the first trimester. It suggests a possible influence of diet on these parameters. Both groups of pregnant women showed hyperphosphaturia through the three trimesters.

The effect of two Ca/P relations (2.1 y 4.5) in the diet on nutritive utilization of both minerals, egg production and egg characteristics (weight, size, resistence and shell Ca content) was studied. Nutritive utilization and absolute body retention of Ca were higher with a Ca/P relation of 4.5, while the lower Ca/P relation (2.1) produced a greater utilization of P, without differences as high as in the case of Ca. As a whole, the diet with a Ca/p relation = 2.1 was more efficiently utilized but egg production did not rise optimal levels got on the diet with a Ca/P relation = 4.5 Egg characteristics were similar with both treatments.

Five experiments were conducted in which various levels of calcium (Ca) and phosphorus (P) were fed to adult male quail (diets D-1: Ca = 1.54%, p = 0.80%; D-2: Ca = 3.20%, P = 0.81%; D-3: Ca = 1.57%, P = 1.66%; D-4: Ca = 3.40%, P = 1.71%; D-5: Ca - 2.20%, P = 0.81%). The interaction between Ca and P, and the effect on some nutritive hematic and osseous parameters were investigated for each diet. Feeding high P caused a body weight decrease in D-4 adult quail (P less than 0.05) and diminished food intake in the birds of trial D-3 (P less than 0.05). The results indicated that the excretion of Ca or P is a lineal function of its own intake. Neither the pattern of relationship between the intake and excretion of Ca was altered by the levels of phosphorus in the diets, nor the levels of calcium altered the pattern of P. With these levels of Ca and P interaction between both nutrients were not demonstrated. Plasma Ca levels and dry weight of femur as well as the ash content in them, were not significantly decreased, although the levels of the latter components were inferior in the groups fed non-adjusted diets in the Ca:P ratio (diets D-1, D-2, D-3 and D-4).

The influence of alimentary calcium deprivation on the nutritional utilization of phosphorus and its corporal retention, after ingestion of diethylstilbesterol has been studied in quail. When female quail are given a highly calcium-deficient diet, egg-laying stops and there follows a substantial decrease in phosphorus utilization and retention, as well as a clear drop in bone mineralization, with calcium and phosphorus content losses in the femur. In males, deprivation of alimentary calcium shows tangible effects on phosphorus retention only when this situation concurs with prior ingestion of diethylstilbestrol.

A study was made of the Ca and P balance, Ca and P content in the femur, physical characteristics of the egg, mineral structure of the shell, and the number of eggs in quails treated with dieldrin (20 mg/kg of diet) for 48 days. The diet contained 3.24% Ca and 0.72% P. The Ca and P balance, the bone contents of Ca and P and the calcemia in the males were not changed by the pesticide. In the females, the pesticide decreased the amount of excreted Ca and Ca in the egg, for which reason the coefficient of nutritive utilization (CNU), the coefficient of corporal retention (CCR), and the Ca level in the femur were greater in treated laying quails. The calcemia remained stable, and the balance of P was not significantly modified by the dieldrin. The study of weight, size, and strength of the egg did not reveal any influence of the dieldrin, and egg production fluctuated throughout the test period.