Apparent digestibility of protein and amino acids in broiler chickens fed a corn-soybean diet supplemented with microbial phytase

Abstract

The effect of microbial phytase supplementation on CP and amino acid (AA) digestibility was investigated in a 28-d trial using 360 sexed, day-old broiler chickens fed corn-soybean meal diets. The experimental design was a completely randomized one with a 3 x 2 factorial arrangement of treatments. The variables included P and Ca levels and phytase: P and Ca levels were: normal P-normal Ca [0.45% available P (Pa), 1.0% Ca], low P-normal Ca (0.35% Pa, 1.0% Ca), and low P-low Ca (0.35 Pa and 0.6% Ca); and phytase at 0 and 600 U/kg diet. Phytase supplementation increased body weight gain (P < 0.014) and feed intake (P < 0.004) at 19 d in male chickens; in females, phytase increased (P < 0.012) only body weight gain at 19 d. The low P-normal Ca diet reduced (P < 0.05) feed intake and body weight gain in both sexes at 7, 14, and 19 d, compared to the normal P-normal Ca diet; the reduction of Ca in the low P diet prevented the above depression, resulting in body weight gain and feed intake to a level comparable to that of the normal P-normal Ca diet. Microbial phytase supplementation had no effect (P < 0.065) on the apparent ileal digestibility (AID) of CP or any AA except Met and Phe in male broiler chickens. In females, adding phytase increased the AID of all AA except Lys, Met, Phe, and Pro. The low P-normal Ca diet reduced (P < 0.05) the AID of Phe, Asp, and Ser in male chickens and reduced the AID of all the AA except Met and Pro in females compared to the normal P-normal Ca diet. The reduction of Ca in the low P diet prevented the depression of the AID of the AA caused by the low P-normal Ca diet, resulting in AID of AA having a level comparable to that of the normal P-normal Ca diet in both sexes. Phytase supplementation did not have any effect (P > 0.05) on apparent "fecal" digestibility (AFD) of CP or any of the AA in male chickens; however, in female chickens it increased the AFD of Thr, Asp, Glu, and Ser. In summary, phytase supplementation increased growth performance in both sexes; increased AID and AFD of most of the AA, particularly in female chickens. The optimum growth performance and AA digestibilities were obtained with the lowest input of resources, in the low P-low Ca diet supplemented with microbial phytase.

Estimating the requirement of dietary crude protein for growing blue-breasted quail (Excalfactoria chinensis)

“…With regard to the higher CP requirements computed by quadratic curvilinear regression and representing the maximum doses required to obtain the best response, Vedenov and Pesti (2008) pointed out that the minimum requirement would be chosen if it was important to avoid wasting dietary CP, whereas use of the maximum requirement would ensure that quails receive sufficient dietary CP. In this study, the minimum requirement results of the weight gain and feed efficiency indices were similar; this similarity was also observed in Japanese quails (Weber and Reid, 1967), Bobwhite quails (Wilson et al, 1977) and broilers (Sebastian et al, 1997). As BWs approached mature values after week 5, the weekly weight gains of quails fed dietary CP of more than 220 g/kg slowed down.…”

Avaliação da matriz nutricional da enzima fitase em rações contendo sorgo para poedeiras comerciais

“…Zootec., v.38, n.10, p. [1948][1949][1950][1951][1952][1953][1954][1955]2009 produzida principalmente por microrganismos do gênero Aspergillus e com capacidade de hidrolisar o fitato, uma molécula que complexa o fósforo (Sebastian et al, 1998), alguns cátions (Gordon & Roland, 1998), energia (Namkung & Leeson, 1999) e aminoácidos (Sebastian et al, 1997), disponibilizando esses nutrientes para aproveitamento dos monogástricos.…”

Efeito da adição de enzimas em dietas de frangos de corte à base de milho e farelo de soja sobre a digestibilidade ileal de nutrientes

“…A média dos valores de digestibilidade ileal da matéria seca e da energia bruta foram maiores (P<0,05) em rações com baixos níveis de Ca e P d , no entanto, para proteína bruta, os maiores valores foram observados nas dietas com baixo nível de Ca e P d (P>0,05). SEBASTIAN et al (1997) não observaram diferença estatística entre os níveis de Ca e P d , dentro do requerimento e dos níveis subótimos, para a digestibilidade da proteína bruta em frangos de corte, contudo, os maiores valores de digestibilidade foram encontrados para os níveis normais, concordando com estes achados.…”

“…O u t r o f a t o r a n t i n u t r i c i o n a l p a r a monogástricos, a molécula de fitato, possui em sua estrutura grupos ortofosfatos altamente ionizáveis, os quais afetam a disponibilidade de cátions como o cálcio, zinco, cobre, magnésio e ferro, no trato gastrointestinal, o que resulta na formação de complexos insolúveis (SEBASTIAN et al, 1997(SEBASTIAN et al, , 1998RIMBACH e PALLAUF, 1998;e SOHAIL e ROLAND, 1999). Os grupos ortofosfatos podem também unir-se a enzimas digestivas e proteínas dietéticas, reduzindo a digestibilidade de carboidratos e aminoácidos (FERKET, 1993;SEBASTIAN et al, 1996;e RAVINDRAN et al, 1999).…”