Dorinha Miriam Silber Schmidt Vitti

Modelo do fluxo biológico do fósforo de fontes de fosfato em suínos, usando o 32P como marcador

The experiment was designed to simulate the mathematical models that relate to the phophorus (P) flow, considering the hypotheses that the endogenous phosphorus from digestive tract was absorbed in the same proportion of the dietary phosphorus and that the input and output flow of this mineral in the compartments was constant. The variables absorption, retention, endogenous P that returns to the gastrointestinal tract (GIT), dietary absorbed P, accretion, reabsorption and balance of P in bone and in soft tissues and P from bone and soft tissue and from the total absorbed that returns to GIT, in growing pigs fed diets containing P from different phosphate sources were evaluate. The model was deterministic and compartmental, in which the GTI (C1), bones (C2) and soft tissues, liver heart, kidney and muscle, (C3) represented the compartments. The information on metabolism and kinetics of the P in tissues obtained by isotopic dilution technique was used. It was concluded that: the hypotheses established in the model were coherent and the obtained values were adjusted to the P flow in pigs; the variables P intake, endogenous P that return to the GIT, P retention, dietary absorbed P, accretion, reabsorption and balance of P from bone and soft tissues and P from total absorbed that returned to the GIT were not influenced by the P from the phosphates sources; the dietary phosphorus could interfere on P distribution in the tissues after the process of absorption of that mineral; the P from total absorbed that return to the GIT was proportional to P intake.

Ação da fitase sobre a disponibilidade biológica do fósforo, por intermédio da técnica de diluição isotópica, em dietas com farelo de arroz integral para suínos

RESUMO - Esta pesquisa foi realizada para determinar as perdas endogenas fecais de fosforo e a acao da fitase sobre a disponibilidade biologica do P nas racoes e no farelo integral de arroz (FAI), para suinos em crescimento, por meio da tecnica de diluicao isotopica. Os leitoes foram distribuidos em delineamento inteiramente casualizado, com quatro tratamentos e tres repeticoes. Os tratamentos consistiram de duas dietas sem FAI (com ou sem 1250 FTU [Unidade de Atividade de Fitase]/kg racao), com 0,34% de P total, e outras duas com FAI (sem ou com 1250 FTU/kg racao), com 0,56% de P total. No 11o dia do experimento, foram aplicados em cada animal, por via endovenosa, 7,4 MBq de 32P. As perdas endogenas fecais nao foram influenciadas pela acao da fitase. A adicao de fitase reduziu o P total excretado nas fezes e melhorou a absorcao e a disponibilidade biologica do P das dietas com farelo de arroz integral.

Metabolismo de cálcio em ovinos em crescimento sob suplementação com diferentes fontes de cálcio: aplicação e comparação de dois modelos matemáticos

This research was conducted to compare the accuracy of two mathematical models to predict calcium (Ca) metabolism in sheep supplemented with different Ca sources. Twenty Brazilian male sheep averaging 7 to 8 months of age were fed a basal diet containing corn, soybean meal, hydrolyzed sugarcane bagasse, urea, mono-ammonium phosphate, mineral mixture and one of the following Ca sources: limestone (LM), alfalfa hay (AH), dicalcium phosphate (DP), oyster shell meal (SM), and citrus pulp (CP). On day 22 each animal received an intravenous injection of 7.7 MBq of radio-calcium (45Ca) followed by collection of blood, feces, and urine every 24 h for 7 days. Total Ca and radioactivity were measured in all samples. At the end of the collection period, animals were slaughtered and samples of liver, heart, kidney, muscles and 12th rib were taken for analysis. Calcium metabolism was evaluated by the models proposed by Vitti et al. (2000) and Fernandez (1995). A completely randomized design was used and means were compared by the Duncan test. No significant differences were observed for Ca intake among treatments. However, total fecal excretion of Ca differed and was lowest in animals fed LM. Calcium balance was negative in sheep receiving AH and CP because Ca absorption might have been compromised by the high contents of pectin and oxalate in these two supplements, respectively. Flows of Ca between the central pool and the digestive tract showed the greatest absorption of Ca on animals fed LM. Diets supplemented with LM, DP, and SM had highest Ca availability with values of 65.38, 34.12 and 32.43%, respectively. The models differed in the predictions of Ca flows among blood, bone and soft tissues but showed similar values for Ca balance in the different compartments. These discrepant results may be explained by structural difference between models.

Phosphorus kinetics in lambs fed different levels of dicalcium phosphate

The purpose of the current work was to study phosphorus (P) metabolism in growing sheep supplemented with different levels of dicalcium phosphate using an extant mathematical model. Twelve male non-castrated Santa Ines sheep, weighing 23 (±2·2) kg, received a basal diet unsupplemented or supplemented with dicalcium phosphate to provide 1-5, 3·0, 4·5 g of P/animal per day (treatments Tl to T4, respectively). After 3 weeks adaptation, 7·4 MBq of 32 P was injected into the jugular vein of each animal. Samples of blood, faeces and urine were collected every day during a 7-day period and thereafter the animals were sacrificed and samples from liver, kidney, heart, muscle and bone were collected for specific activity and inorganic P determinations. The flows between gut and plasma were similar for each treatment except for Tl, which showed the lowest values for both flows (P<0·05). The amount of P accreted to soft tissue (F 42 ) was different among treatments, however net tissue retention was similar for all treatments. Total P retained was highest for T4 and lowest as well as negative for Tl and T2. Phosphorus accreted to bone (F 32 ) was different among treatments and contributed to the different net bone retentions. The highest value of F 32 was reached by animals on T4, whilst the lowest values were found for animals on Tl. Despite having the highest value of F 32 , it should be noted that animals on T4 excreted the most P in faeces. Considering concerns about environmental P pollution, it is important to be aware that the treatment which provided the highest value for net bone P retention and for F 42 also led to the highest value of P excreted in faeces. Therefore, the current study suggests that T3 provided the best P level for this category of animal since P accreted to bone and tissue indicated that P absorption was adequate to attend to P requirements.

Determinação da biodisponibilidade do fósforo de diferentes fontes pela técnica de diluição isotópica, em suínos em crescimento

Twenty-eight male pigs averaging 28.95 kg were used to determine endogenous fecal losses, true absorption and phosphorus bioavailability in different phosphorus sources. The experiment was arranged in randomized blocks, with seven treatments and four repplicates and one pig/box. The diets were corn and soybean meal-based and the phosphorus (P) was supplemented through different phosphate sources: dicalcium (FBC), monodicalcium (MBC), triple superphosphate (ST), simple superphosphate (SS), Catalao rock (ROCHA) and phosphoric acid (AcF) and diet control without supplemental P (CONT). Phosphorus intake, excretion through feces and urine, retention and absorption were lower in the diet with smaller phosphorus level. Supplemental inorganic P did not affect intake, endogenous fecal P and retained P. However, the P excretion in the feces was smaller for the animals fed SS and greater for those fed ROCHA. P excretion in the urine was greater for the animals fed AcF and smaller for those fed ROCHA. It can be concluded P bioavailability was of 43.82, 89.44, 82.65, 76.90, 98.73, 90.03, and 63.26 for the treatments CONT, FBC, MBC, ST, SS, AcF and ROCHA, respectively.

Fluxo biológico do fósforo no metabolismo de suínos alimentados com dietas contendo fitase

The study was conducted to evaluate the biological flow of P in pigs fed diets based on corn, soybean meal, defatted rice bran (DRB) and soybean oil, with increasing phytase levels (253, 759, 1265 and 1748 PU/kg of diet), using mathematics models. The model was deterministic and compartimental, in which the gastrintestinal tract (GIT) (C1), the plasma C2, the bones (C3) and the soft tissues (liver, heart, kidney and muscle) (C4) represented the compartments. Metabolism data and kinetics of P in tissues were used in the model, obtained by the isotopic dilution technique. The parameters used were: absorption, retention, endogenous P that return to the gastrintestinal tract (GIT), dietary absorbed P, accretion, reabsorption, balance of P in bone and soft tissues and P from total absorbed that returned the GIT. The biomathematical model used is adequate to explain the P flow in growing pig. The phytase enzyme interfere in biological flow of P from compartment C1 to C3 and with the output flow of P from compartment C3 and C4 to C1. The level of 759 PU of phytase in diet of growing pig availability more efficientily the organic phosphorus for the pigs metabolism.

Misleading relationships between in situ rumen dry matter disappearance, chemical analyses and in vitro gas production and digestibility, of sugarcane bagasse treated with varying levels of electron irradiation and ammonia

Twelve samples of sugarcane bagasse, representing untreated material or bagasse irradiated with doses of 200, 400, 600, 800 and 1000 KGy in an electron accelerator and afterwards with or without 20 g/kg dry matter (DM) of NH3. These were analysed for changes in neutral detergent fibre (NDF), phenolic compound and reducing sugars content. DM disappearance was evaluated using both 48 h in situ and in vitro incubations, 0 h DM disappearance (washing losses) and in vitro volatile fatty acid (VFA) production. In situ disappearance was highly correlated with NDF (negatively), phenolic compound (positively) and reducing sugar (positively) content. However, washing losses were similarly correlated to NDF, phenolic compounds and reducing sugars, and little variation in either in vitro gas or VFA production was recorded. It is therefore concluded that the variations in situ disappearance observed were an artefact of washing losses and did not accurately reflect differences in rumen fermentability. These results may help to explain why the performance of animals, reported in the literature, offered treated bagasse is not as good as that anticipated from in situ analyses. # 1999 Elsevier Science B.V. All rights reserved.

Phosphorus kinetics in calves experimentally submitted to a trickle infection with Cooperia punctata.

Ten male Holstein calves (74.3+/-3.2 kg LW) were used for a trial with trickle infection with Cooperia punctata to evaluate phosphorus (P) kinetics. Five calves were inoculated with 10,000 L(3) stage larvae per week during 35 days, while the other group of five calves was kept as a control. On the 29th day each calf was intravenously injected with 29.6 MBq of a (32)P solution. Blood samples were taken at 24 h periods for 7 days, after which all calves were slaughtered and worms burdens. Faeces, urine and tissue samples were taken for analysis using isotopic dilution and modeling techniques. The number of eggs per gram of faeces (EPG) was 1920+/-168 on 28th day and the total number of worms burdens was 11,131+/-1500. Infected calves showed lower feed intake and live weight gain, as well as lower P intake, absorption and retention than control calves. The P flows between body compartments were lower for blood to gastrointestinal tract (TGI), TGI to blood, blood to soft tissues, bone balance and soft tissue balance in infected calves when compared to the control. The trickle infection of C. punctata affected P metabolism due to the decrease in P retained and live weight due to fall in feed intake.

IRRADIAÇÃO DE RESÍDUOS FIBROSOS COM FEIXES DE ELÉTRONS: EFEITOS NA COMPOSIÇÃO QUÍMICA E DIGESTIBILIDADE

Samples of sugarcane bagasse, rice and cotton residues were irradiated with various doses (200, 400, 600, 800 and l000kGy) in an electron accelerator with or without anhydrous gaseous NH3 post-treatment, to evaluate the effects of irradiation on dry matter digestibility and on their chemical and physical properties. After irradiation, samples were dried and ground for chemical analysis. Dry matter digestibility was determined with the nylon bag technique. Structural analysis was performed using light and electron microscopy. Crude fiber and neutral detergent fiber significantly decreased (P<0.01) for irradiated samples. Phenolic contents increased with the applied dose indicating that lignin was decomposed. Dry matter digestibility increased with increasing dose. An increase of 24 digestibility units was observed for bagasse at highest dose. Based on microscopy, fragmentation of sugarcane bagasse was observed at 800-1000kGy and some celular alterations occurred at 200kGy for rice and cotton residues. lt was concluded that irradiation caused significant changes on chemical and physical properties and on digestibility of fibrous residues. Utilization of irradiated biomass for animal feed appears promising.

Fisiologia digestiva de suínos alimentados com rações contendo diferentes fontes de fósforo

The source of phosphorus of better quality for use in the pig feeding and that cause less environment impact by the excretion of phosphorus in the enviroment was evaluated. Twenty-one male pigs weighting 34.94 ± 2.88 were fed corn-soybean meal based diets supplemented with different P sources: control without P supplementation P (Cont), dicalcium (FBC), monodicalcium (MBC), triple superphosphate (ST), simple superphosphate (SS), Catalao rock (Rocha) and phosphoric acid (AcF). The experiment was designed to evaluate the P availability and P excretion to environment. The experiment was arranged in randomized blocks, with seven treatments and three replicates and one pig/box. The model was deterministic and compartimental, in which the gastrointestinal tract (GIT) (C1), plasma C2, bones (C3) and soft tissues (liver, heart, kidney and muscle) (C4) represented the compartments. Metabolism data and kinetics of P in tissues were obtained by the isotopic dilution technique. The simple superphosphate is the phosphorus source with the smallest capacity for polluting the environment, best bioavailability and most efficient use for the metabolism of growing swine.