Influence of microbial phytase on apparent ileal amino acid digestibility of feedstuffs for broilers

Abstract

The influence of microbial phytase on the ileal amino acid digestibilities in three cereals (corn, sorghum, and wheat), four oilseed meals (soybean meal, canola meal, cottonseed meal, and sunflower meal) and two cereal by-products (wheat middlings and rice polishings) was determined using 5-wk-old broilers. Supplementation of microbial phytase (1,200 FTU/kg) improved (P < 0.001 to 0.10) the digestibilities of protein and amino acids in all feedstuffs, but the magnitude of response varied depending on the feedstuff and the amino acid considered. Mean digestibility of the 15 amino acids in the feedstuffs without and with phytase were: corn, 78.0 and 80.4%; sorghum, 74.7 and 79.4%; wheat, 77.7 and 84.6%; soybean meal, 82.2 and 85.5%; canola meal, 78.7 and 80.7%; cottonseed meal, 70.8 and 74.2%; sunflower meal, 76.7 and 80.2%; wheat middlings, 70.8 and 73.4%; and rice polishings 62.1 and 66.9%, respectively. When individual amino acids were considered, the increments in digestibility were relatively higher for threonine and valine. This effect was consistent across all feedstuffs. The observed variations in response among feedstuffs were influenced by the inherent protein digestibility, but not by dietary phytic acid concentration. No correlations were determined between the dietary concentrations of phytic acid and phytase responses in terms of protein digestibility (r = 0.20; P > 0.31) and mean amino acid digestibility (r = 0.12; P > 0.51); however a significant negative correlation was observed between inherent protein digestibility and phytase responses in protein digestibility (r = -0.42; P < 0.03). It appears that solubilities of phytate salts and protein, and their influence on the degree of phytate-protein complexing in different feedstuffs, may be more relevant than total phytic acid concentrations. Interestingly, dietary phytic acid concentrations were negatively correlated with inherent protein (r = -0.81; P < 0.001) and mean amino acid (r = -0.85; P < 0.001) digestibilities of the feedstuffs evaluated in this study.

Separate feeding of calcium improves performance and ileal nutrient digestibility in broiler chicks

“…Another possible outcome would be reduced substrate availability (Ca 2+ ) used in the formation of ternary protein-phytate complexes. The results of this study support previous findings that dietary Ca concentration influences the digestibility of N and amino acids (Ravindran et al 1999;Selle et al 2009). In the present study, the improvement of apparent digestibility of amino acids was broadly in keeping with the results of Cowieson et al (2006) who reported ingestion of fully phosphorylated phytate (IP 6 ) adversely affected the true digestibility coefficients of alanine, serine, aspartic acid and threonine to a greater extent than other amino acids.…”

Influence of L-lactic acid on the efficacy of microbial phytase in broiler chickens

“…In recent years, some researchers reported that microbial phytase had a beneficial effect on the utilization of nutrients other than phosphorus, such as amino acids (Yi et al, 1996;Namkung and Leeson, 1999;Ravindran et al, 1999Ravindran et al, , 2000. Furthermore, several studies showed that added phytase improved ileal amino acid digestibility in individual feed ingredients (Ravindran et al, 1999;Rutherfurd et al, 2002) and in complete diets (Yi et al, 1996;Namkung and Leeson, 1999;Ravindran et al, 2000).…”

“…Furthermore, several studies showed that added phytase improved ileal amino acid digestibility in individual feed ingredients (Ravindran et al, 1999;Rutherfurd et al, 2002) and in complete diets (Yi et al, 1996;Namkung and Leeson, 1999;Ravindran et al, 2000). However, this topic remains still controversial because in some other experiments only marginal or even no effects were observed (Sebastian et al, 1997;Biehl and Baker, 1997;Zhang et al, 1999;Peter et al, 2000).…”

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

“…Estes resultados confirmam o efeito benéfico da fitase microbiana sobre a hidrólise Tabela 1 -Composição das dietas experimentais (% matéria natural) do ácido fítico, incrementando a digestibilidade ileal de nutrientes nas dietas de frangos. As bases para estes achados estão se tornando evidentes e claramente relacionadas com a capacidade do ácido fítico em se ligar a proteínas, aminoácidos, amido e lipídios e da habilidade da enzima em liberar os nutrientes complexados à molécula, pela hidrólise do ácido fítico (RAVINDRAN et al,1999). 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).…”

“…No entanto, alguns estudos demostraram melhoras similares às encontradas neste trabalho (MARSMANN et al, 1997;RAVINDRAN et al, 1999;ZANELLA et al, 1999;e NAMKUNG e LEESON, 1999).…”