The effects of dietary available phosphorus levels and phytase on performance of young and older laying hens

Abstract

In the first of two experiments (20 to 70 wk of age), eight treatments consisted of corn-soybean meal diets (0.34% total P, 3.8% Ca, 17% CP, 2,758 kcal ME/kg) containing 0.10, 0.15, 0.20, 0.25, or 0.45% available P (AP), with the three lowest AP diets supplemented with 300 units of phytase/kg of diet. A second experiment evaluated the effect of feeding the 0.10% AP diet with and without phytase on performance and time required for onset of P deficiency in older hens (70 to 76 wk of age). In Experiment 1, the 0.10% AP diet with no supplemental phytase depressed performance by 28 wk of age. No other significant differences in performance were observed among treatments for the entire 20- to 70-wk period except that the 0.15% AP diet with no phytase resulted in body weights and tibia ash that were lower (P < 0.05) than those of hens fed the 0.45% AP diet during the last 30 wk. The mean daily AP intake of hens fed the 0.10% AP, 0.15% AP, 0.45% AP, or 0.10% AP + phytase diets was 94,159, 499, or 108 mg, respectively. Excreta P concentration was decreased by approximately 50% in birds consuming 0.10% AP + 300 U/kg phytase compared with those consuming 0.45% AP. In the second experiment, P deficiency signs occurred within 3 wk of consuming the unsupplemented corn-soybean meal diet (0.10% AP) compared with 8 wk in Experiment 1. The results of this study indicate that phytase improves P utilization in corn-soybean meal diets for laying hens and that a corn-soybean meal diet containing 0.15% AP (159 mg AP/d) or containing 0.10% AP + 300 units of phytase/kg (108 mg AP/d) supported optimal egg production from 20 to 70 wk of age. Additionally, results suggested that older hens may exhibit P deficiency symptoms sooner than younger hens.

Reduction of the nutritional values of diets for hens through supplementation with phytase

“…Boling et al (2000) also found no significant differences in specific gravity of eggs of hens from 20 to 60 weeks of age fed 0.10% available phosphorus and 300 FTU of phytase/kg in the ration. The nutrient levels in the diet significantly influenced the Haugh unit, and the values improved as it reduced the supply of CP, ME, Ca and P in the diets.…”

“…Silva et al (2008) using 300 FTUof phytase supplemented in the diet of hens found no significant differences in food consumption. Accordingly, Boling et al (2000) and Liebert et al (2005) also reported no effect of phytase supplementation on this variable. Table 2 -Effect of nutrient levels (N) and phytase on egg production, weight, mass and conversion by egg mass a,b,c -Means in the columns followed by different lower case letters statistically differ by SNK test at 5% of probability.…”

Alternatives to the Use of Antibiotics in Egg Production

“…The enzyme xylanase, for example, is responsible for the degradation of non-amidic polysaccharides and is not produce by monogastric animals [13]. According to [14] the use of exogenous enzymes, such as phytase, allows alternative ingredients to be as efficient as corn and soy. In a study by [14], exogenous phytase supplementation for chickens, over 70 weeks of age increased the use of dietary phosphorus, and the birds maintained egg laying.…”

“…According to [14] the use of exogenous enzymes, such as phytase, allows alternative ingredients to be as efficient as corn and soy. In a study by [14], exogenous phytase supplementation for chickens, over 70 weeks of age increased the use of dietary phosphorus, and the birds maintained egg laying. On the other hand, birds that did not receive exogenous phytase in the diet had low posture indexes.…”

Exigência de fósforo disponível para frangos de corte machos e fêmeas de 1 a 21 dias de idade

“…aminoácidos sulfurados e da lisina (BOLLING et al, 2000). O fósforo, entre suas principais funções, é considerado elemento essencial para a formação da estrutura óssea, participa da formação de membranas celulares, é componente dos ácidos nucléicos envolvidos no crescimento e na diferenciação celular, participa na manutenção do equilíbrio osmótico e eletrolítico, é essencial para utilização e transferência de energia (na forma de ATP), necessário para a formação dos fosfolipídeos, o transporte de gorduras e a síntese de Rev.…”