Response of broiler chickens to microbial phytase supplementation as influenced by dietary phytic acid and non-phytate phosphorous levels. II. Effects on apparent metabolisable energy, nutrient digestibility and nutrient retention

Abstract

1. Male broilers (n=900) were fed on wheat-sorghum-soyabean meal based diets containing 3 concentrations of phytic acid (10.4, 13.2 and 15.7 g/kg; equivalent to 2.9, 3.7 and 4.4 g/kg phytate P), 2 concentrations of non-phytate (or available) phosphorus (2.3 and 4.5 g/kg) and 3 concentrations of microbial phytase (0, 400 and 800 FTU/kg) from day 7 to 25 post-hatch. The dietary concentrations of phytic acid were manipulated by the inclusion of rice pollards. All diets contained celite (20 g/kg) as a source of acid-insoluble ash. 2. The apparent metabolisable energy (AME) concentrations of the diets were determined using a classical total collection procedure during the 3rd week of the trial. On d 25, digesta from the terminal ileum were collected and analysed for phosphorus, nitrogen and amino acids. Nutrient digestibilities were calculated using acid-insoluble ash as the indigestible marker. 2. Ileal digestibilities of nitrogen and essential amino acids were negatively influenced by increasing dietary levels of phytic acid but these negative effects were overcome by the addition of phytase. 3. Supplemental phytase increased AME, ileal digestibilities of phosphorus, nitrogen and amino acids and the retention of dry matter, phosphorus and nitrogen in broilers. There were no differences in the phytase responses between additions of 400 and 800 FTU/kg. 4. The responses in all variables, except AME, were greater in low non-phytate phosphorus diets. 5. In the case of AME, the response to added phytase was greater in adequate non-phytate phosphorus diets. Supplemental phytase increased AME values from 13.36 to 13.54 MJ/kg dry matter in low non-phytate phosphorus diets and from 12.66 to 13.38 MJ/kg dry matter in adequate non-phytate phosphorus diets.

Níveis de cálcio e fósforo disponível em rações com fitase para frangos de corte nas fases pré-inicial e inicial

“…Os resultados de desempenho obtidos neste ensaio (1 a 7 dias) sugerem que a fitase (500 ftu/kg de ração) foi eficiente em liberar parte do fósforo fítico presente nas rações. Isso concorda com vários autores que relataram a ação benéfica dessa enzima sobre os grupamentos fíticos (Ravindran et al, 2000;Kornegay, 2001;Choct, 2006 Tabela 3 -Desempenho de frangos de corte, no período de 1 a 7 dias de idade, alimentados com rações contendo fitase e diferentes níveis de fósforo disponível e cálcio resultados de desempenho, pois é preciso considerar também a adequada mineralização óssea. Se comparadas à ração controle sem fitase, as rações avaliadas não acarretaram diferença significativa (P>0,05) na porcentagem de cinzas ósseas (Tabela 4).…”

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

“…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).…”

“…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).…”

Gross responses and apparent ileal digestibility of amino acids and minerals in broiler chicken fed vegetable-based starter diets supplemented with microbial enzymes

“…Inclusion of enzymes in plant diets enables the birds to degrade the antinutritive feed components along with promoting the breakdown of starch, cell walls, and storage proteins (10). However, many previous researchers have reported that the efficacy of such enzymes seems to be unpredictable in some cases and depends partially on the substrate or the nature of the diet composition including many other factors (11)(12)(13). The current study was undertaken to assess the relative nutritional merits of the two leading vegetable protein sources, SBM and CM, when fed with or without carbohydrase (Avizyme) and phytase enzyme supplements.…”