**4. Material and procedures**

Data in table 1 demonstrate the economic relevance of the products under consideration in this study for the Brazilian feed industry. Foreign products are also of concern, as long Brazilian crops and animal yields rely on a great amount of imported phosphate prod‐

184 Imaging and Radioanalytical Techniques in Interdisciplinary Research - Fundamentals and Cutting Edge Applications

Indeed, any phosphate mined worldwide may contain accessory-gangue minerals and

The United States Agency for Toxic Substances and Disease Registry [19] publishes the CERCLA Priority List of Hazardous Substances that includes substances, which have been determined to be of the greatest public health concern [19]. Uranium is the 97th substance

**Rank Substance Total Points\***

1 Arsenic *1665*

5 Polychlorinated Biphenyls *1344*

**97 Uranium** *832*

\*The ranking of hazardous substances on the CERCLA Priority List is based on three criteria (i,ii,iii). They form altogether the Total Score = Σ (i) Frequency of Occurrence + (ii) Toxicity + (iii) Potential for Human Exposure = Σ (i) up to 1.800 Points

This study deals with the uranium, since to face the main constraints low inherent P in soil and plants, rock phosphates are likely to be more extensively disseminated in the agriculture and these phosphorus sources carry uranium from their structures to the environment and

Uranium is the heaviest natural element in the nature; it is hazardous element in man and animal health, not just it presents radioactivity but also it presents metallotoxicity once it is a heavy metal. Furthermore, uranium presents many radionuclides with high radioactiv‐

Health implications of human exposure to uranium are well documented: cancer, liver and

Uranium in nature is more plentiful than silver (Ag) and about as abundant as arsenic (As). It is found in very small amounts in the form of minerals, especially in rocks, soil, water, air, plants and animal tissues that could be consumed as food containing varying

+ (ii) up to 600 points + (iii) up to [300 concentration points + 300 exposure points] [20]

kidney diseases and reproduction impairment [21,22].

**Table 4.** Compilation of some hazardous substances (including uranium) in the CERCLA List [19, 20]

impurities that can be hazardous to man and animal such: Cd, Hg, Pb and V [16].

ucts (tables 2 and 3).

ranked in the list (table 4).

human food chain as well [21].

ity and energy [22].

amounts of uranium [23].

*Phosphate sample preparation*: phosphates were acquired in the local market of Minas Gerais. Aliquots of 100 grams were randomly taken for each product pack to be grounded to obtain a particle size of 200 Tyler mesh (75 μm) establishing similar conditions for all samples (99% of conformity of the particle size of each product). Aliquot of 1000 mg of each grounded product was weighted and sealed in small polystyrene capsules.

*Animal breeding:* Two groups of twelve (6 females and 6 males) New Zealand white rabbits (30 days of life) were selected and separated in two groups housed individually receiving a different phosphorus source (dicalcium phosphate and bovine bone meal).

Two rabbit feeds were designed to allow the introduction of the P source and to offer sufficient nutrient intake to meet rabbit nutritive requirements. Each one of the feeds had the same 98 percent (dry basis) of fiber, energy, and amino acids. Both formulations were based in raw materials as %, dry basis: Alfalfa meal 34.63, Soy oil 1.00, Sugar cane 2.00, Salt 0.50, Lysine 0.25, Methionine 0.04, Limestone 1.0, Premix 0.40, Maize 6.05, Wheat straw 25.0, Soybean meal 12.13, Maize by products 15.00 and the remaining 2.0 from the selected P source – dicalcium phosphate and bone meal, both materials analyzed in first part of the experiment.

Feeds were processed in order to turn the mixed products into a compact mixture. After that, the meal was conditioned by mixing it on dry steam in a conditioner; this conditioned product was pressed by rolls to pass through the holes of the pelleting die which shapes the meal into the final pellet shape of 3.00 mm to permit a good balance between pellet quality and good intestinal motility.

Animals were housed in stainless steel cages with a fenestrated floor to allow feces to drop through into a pan. Absorbent material was placed in the pan to collect urine and minimize ammonia release due to the bacterial breakdown of urea.

Good quality water was provided through a nipple-drinking system that provides water at all times. Food was provided by a J-hopper attached to the front of the cage. J-hopper prevents the rabbit from defecating in their food. Animals were fed *ad libitum* from 30 to 72 days - age considered as ideal slaughtering that allows rabbit to reach its commercial live weight, i.e. 2.0 kilograms.

**6. Results**

a

**Phosphate Total U [μg.g-1] Ratio P:U**

Nuclear Analytical Techniques in Animal Sciences: New Approaches and Outcomes

http://dx.doi.org/10.5772/55071

187

**Phosphorus Source U Concentration [μg.g-1]** Dicalcium Phosphate 1.25 ± 0.45a Bovine Bone Meal 0.91 ± 0.29a

)

<sup>a</sup> The results were evaluated (p ≤ 0.05) by t-test using Microsoft Excel 2000 software [26]. Means with the same letter (a

**Table 6.** Uranium content in the *longissimus dorsi* muscle from rabbits fed with two different sources (as 2% in the

Concentrations of uranium are quite variable in the phosphate products. The average ratio of phosphorus to uranium in phosphates appeared not to be only related to their origin since all tested Brazilian phosphates are from igneous deposits (ratio varying from 1000-4000 atoms of phosphorus to 1 atom of uranium), instead the foreign data are related exclusively to sedi‐ mentary rocks (ratio varying from 300-2400 atoms of phosphorus to 1 atom of Uranium). Differences amongst tested products are the region of exploitation of phosphate ores that implies different ages of mineralization, deposit types and accessory minerals associated that may vary in phosphates of the same origin, and finally they are separated by the routes of

No significant difference was observed in uranium presence in the muscle tissues from rabbits (tab. 6) receiving dicalcium phosphate and those animals receiving bovine bone meal: average

Amm. polyphosphate, 45% P2O5 *, Brazil* 37 ± 4a 5580:1 Super-simple phosphate, 17% P2O5 *, Brazil* 49 ± 5a 1485:1 Dicalcium phosphate, 45%, P2O5 *, Brazil* 187 ± 9a 1050:1 Monoamm. phosphate, 51% P2O5 *, Brazil* 183 ± 9a 1215:1 Super-triple phosphate, 45% P2O5 *, Brazil* 34 ± 4a 3975:1 Israeli rock phosphate, 31% P2O5 *, Israel* 145 ± 7a 935:1 Rock phosphate, 31% P2O5, *Florida, USA* 59b 2300:1 Rock phosphate, 28% P2O5, *Tanzania* 390b 303:1 Rock phosphate, 29% P2 O5, *Mali* 123b 1030:1 Bovine Bone Meal 1.0 ± 0.8a 27650:1

U experimental results by Delayed Neutrons Technique, P by Colorimetric Method

**Table 5.** U content and the ratio [phosphorus: uranium] in the tested phosphates

feed) of phosphorus, n=12. The data are presented as mean ± SD, raw basis.

production of each final product for those are industrialized.

b U and P data extracted from FAO/IAEA [16]

are not significantly different.

**7. Discussion**

The 24 rabbits were slaughtered via humanitarian euthanasia and their *longissimus dorsi* muscles were extracted and prepared by freeze-dry process in order to be irradiated. Approximately 100 g of each specimen was frozen at –70°C and lyophilized. Each freezedried sample was powdered and homogenized and around 1000 mg was taken into polyethylene irradiation vials.

*Irradiation:* Each one of the full-filled capsules with samples was placed in a polyethylene container for the pneumatic transporting system. Individually, samples and standards in the vials were transported into the neutron flux using the pneumatic transport system of the reactor IPR-R1 in the CDTN/CNEN (Centre of the Nuclear Technology Development) in Belo Horizonte, Brazil. The reactor was operated at 100 kW-thermal power under a neutron flux of 6.6x1011 neutrons.cm2 .s-1. Additionally, phosphates were studied by the well-established Colorimetric Method to assess their phosphorus - P2O5 content, at the EC-4 Sector of the Nuclear Technology Development Centre, institute from the Brazilian Nuclear Energy Commission (CDTN/CNEN).
