Study on the transport of serum iron in 2 species of palmiped birds

Abstract

Generally, studies on the Fe metabolism in birds consulted by us (1, 2, 3, 5, 12, 13) analize aspects different to the ones weare particulary interested. The mechanism of iron transport in blood constitutes, on the contrary, our principal purpose, and we have alreadjr analyzed this problem in turkey (6) and hen (7), aside from other similar studies in mammals (8, 9).

The special characteristics of the iron metabolism found

by us in the lien during the laying period (7), suggested future investigations in other birds in identical State.

We have studied two species of palmiped birds : the duck (Anas platyrhynca, var. Kaki-Canipbell) and the common white goose (Anser anser).

The blood samples have been obtained from the wing vein and taking the plasma by ways of centrifuging the heparinized blood.

Serum iron (S) and total iron-bindig capacity (TIBC) were determined in accordance with Ramsay (10, 11), and with these valúes, the saturation coeficient (SC) of siderophilin was cal­ culated.

The results statistically elaborated (Student’s t), assembled in the tables I (ducks) and II (geese) in three different groups : males, non-laying females and laying females.

The contents of serum iron in both males and non-laying females of both species show a certain uniformity (mean va­ lúes of 132 y and 163.8 y Fe %, tables I and II) and cannot be found significant differences either between sexes or between species. The laying females, on the contrary, constitute a clearly differentiated lot (mean of 1065 y Fe % in ducks and1260 y Fe % in the geese) with an increase of serum iron, this being much greater than that found in hens (7). It is evident that there is a relation between the beginning of the laying

period and the increase of serum iron (fig. 1) with a special increase at the beginning.

On the other hand, the valúes of the TIBC do not have significant differences, but it should be noted the average va­ lúes are clearly raised (472 and 635.5 y Fe %). The absolute concentraron of siderophilin calculated from them, gives valúes which range from 0.42 and 0.44 gr/100 and which are much more superior than those noted on men (4), and to those which can be calculated from cur observation with the turkejr (6) and the hen (7). The valúes of TIBC in each specimen also show a certain variation in relation with the laying (Fig. 2) and follow the in- dicated variations for the serum iron.

The siderophilin is found normally satured in a 25 to 29 %. Similar valúes are found in the turkeys. In laying females, the saturation coeficients (SC) exceed the 100 %, and it is more noticeable here (227.5 %) than what can be observed in the hen (7).

The inversión in the valúes of the serum iron and the TIBC which at first sight resembles abnormal, can also be noted in the females ducks and females geese. This abnor

mality can be explained by the knowledge of the technique of determination of the TIBC (11), in which CO3Mg is applied to absorb the Fe surplus. The determination of serum iron, previous to the treatment with carbonate, also determines a clear decrease in the Fe concentration (table III) of the serum from laying females, but does not affect the serum iron de- terminations in the samples from males and non-laying fe- males. It should be pointed out how the average valué of the serum iron, before the treatment with CO3Mg, is almost the same as that of the TIBC (table III). This shows us how* by following the Ramsav's technique the siderophilin should transport only 50 % of the circulating iron. The already published data on hens (7) have allowed us to reach a similar conclusión.

We must still elucídate if anyother protein fraction colla- borates in the transport or if it is the same siderophilin which has another iron-binding mechanism much more labile, so that the carbonate is capable of adsorbing it.