Phosphorus availability of rock phosphates as compared with feed-grade phosphates for swine Disponibilidade de fósforo em fosfatos de rocha em comparação à de fosfatos bicálcicos para suínos

One hundred ninety two swine were used in a trial to assess the relative bioavailability of phosphorus (RBP) in six phosphate sources. Phosphates were three feed grade phosphates (FP), two made in Brasil, and one USA made, and three rock phosphate samples (RP) originated from two mines sites in Brasil, and one mine site in Israel. Levels of calcium, phosphorus and fluorine in RP were 29, 12 and 1.7% (RP source 1), 33, 14 and 1.4% (RP source 2), and 30, 14 and 3.6% (RP source 3), respectively. Pigs were fed a corn-soybean meal basal diet (18% CP, 0.95% Lys, 0.75% Ca, 0.37% P) or the basal diet with 0.15% P from a standard purified grade calcium phosphate (SP), or with 0.15% P from experimental FP or RP. Each diet was fed to six pen replicates of four pigs per pen for 35 days (14.4 to 39.9 kg). Weight gain (WG), feed/gain (FG), plasma P (PP), bone ash (BA), and breaking strength of metacarpals and metatarsals (BS-MM) and femurs (BS-F) were improved by phosphorus addition. However, performance and bone parameters were depressed by RP, as compared to FP dietary supplementation. WG, BA, BS-MM and BS-F were regressed to P added, and slope-ratios were calculated to assess RBP in the FP and RP sources. The average bioavailability of P in the FP and RP sources, relative to SP, were 89 and 49% (WG), 112 and 49% (BA), 78 and 28% (BS-MM), and 101 and 52% (BS-F), respectively. Low animal performance and bone strength related to toxicity should be expected if rock phosphates are used to feed pigs.<br>Cento e noventa e dois leitões foram usados em um experimento para avaliar a biodisponibilidade relativa do fósforo (RBP) em seis fontes fosfáticas. As fontes foram três fosfatos de uso em nutrição (FP), dois fabricados no Brasil e um nos Estados Unidos, e três amostras de fosfatos de rocha (RP), originados de duas minas brasileiras e uma mina situada em Israel. Os níveis de cálcio (Ca), fósforo (P) e flúor (F) nos fosfatos de rocha foram 29, 12 e 1,7% (fonte RP 1), 33, 14 e 1,4% (fonte RP 2) e 30, 14 e 3,6% (fonte RP 3), respectivamente. Os suínos foram alimentados com uma dieta basal de milho e farelo de soja (18% PB, 0,95% Lis, 0,75% Ca, 0,37% P) ou dieta basal contendo 0,15% P a partir de um fosfato bicálcico purificado padrão (SP), ou com 0,15% P a partir das fontes experimentais FP ou RP. Cada dieta foi fornecida a seis baias (replicatas) com quatro leitões durante 35 dias (14,4 a 39,9 kg). O ganho de peso (WG), a conversão alimentar (FG), o P plasmático (PP), as cinzas ósseas (BA) e a resistência óssea à quebra de metacarpos e metatarsos (BS-MM) e fêmures (BS-F) melhoraram com a adição de fósforo às dietas. Contudo, o desempenho e os parâmetros ósseos pioraram com o uso dos fosfatos de rocha, em comparação à suplementação dietética de FP. A análise de regressão dos dados de WG, BA, BS-MM e BS-F em relação ao P adicional foi realizada e foram calculadas slope-ratios para avaliar a RBP nas fontes de FP e RP. A biodisponibilidade média do P nas fontes FP e RP, relativas ao SP (com valor atribuído de 100), foram 89 e 49% (WG), 112 e 49% (BA), 78 e 28% (BS-MM), e 101 e 52% (BS-F), respectivamente. Baixos desempenho e resistência óssea relacionados à toxicidade devem ser esperados se fosfatos de rocha forem utilizados na alimentação de suínos

Available phosphorus levels for 95 to 120 kg barrows genetically selected for lean gain

With the objective of evaluating available phosphorus (aP) levels in diets for barrows selected for lean meat deposition, eighty commercial hybrid pigs with initial weight of 94.05±1.05 kg were used in this experiment. Pigs were allotted in a completely randomized block design, with five treatments (0.092, 0.156, 0.220, 0,284, and 0.348% of aP), eight replicates and two pigs per experimental unit. The average daily weight gain of pigs increased and the feed conversion improved quadratically with increasing aP in the diets up to the estimated levels of 0.21 and 0.20%, respectively. There was no effect of the dietary aP on average daily feed intake. However, aP intake, bone strength and concentration of phosphorus in the bones increased linearly with increasing aP in the diets. The levels of aP did not affect carcass traits; however, the alkaline phosphatase activity was improved and the values of serum inorganic phosphorus increased quadratically up to the estimated levels of 0.26 and 0.27% of aP, respectively. The available phosphorus levels of 0.21, 0.27, and 0.35%, corresponding to daily aP intakes of 6.34, 8.13, and 10.44 g result, respectively, in greatest performance, blood and bone parameters of 95 to 120 kg barrows selected for lean gain

Available phosphorus in diets for 15 to 30 kg pigs genetically selected for meat deposition

With the objective to evaluate the effect of dietary available phosphorus levels (aP) on the performance, blood and bone parameters of castrated male and female pigs, genetically selected for meat deposition, 60 commercial hybrids pigs with initial weight of 15.54±0.68 kg were allotted in a completely randomized block design, with six treatments (0.103, 0.210, 0.317, 0.424, 0.531, and 0.638% aP), five replicates, and two animals per experimental unit. Pigs were fed ad libitum and water was provided until the end of the experimental period (21 days), when animals reached 31.31±2.94 kg. Daily weight gain and daily feed intake increased, while the feed conversion improved quadratically up to 0.534, 0.487, and 0.574% aP maximum responses, respectively. The aP intake and the values of inorganic phosphorus in serum increased linearly with increasing the levels of aP in the diets. Alkaline phosphatase activity increased quadratically up to 0.558% maximum response. Bone breaking strength and calcium, phosphorus, and ash contents in the bones increased linearly with increasing aP concentration in the diets. The available phosphorus requirement of castrated male and female pigs genetically selected for meat deposition from 15 to 30 kg for best results of performance is 0.574%, corresponding to a daily intake of 8.26 g of available phosphorus