An in vitro procedure for studying enzymic dephosphorylation of phytate in maize-soyabean feeds for turkey poults

Abstract

An in vitro method was developed to predict inorganic P release from maize-soyabean poultry feeds containing supplemental phytase (EC 3.1.3.8), and to quantify the effect of acid phosphatase (EC 3.1.3.2), fungal protease (EC 3.4.23.6) and Aspergillus niger cellulase (EC 3.2.1.4) on phytate dephosphorylation. Pepsin (EC 3.4.23.1) and panmatin digestion periods were preceded by a 30 min pre-incubation at pH 525 to simulate digestion in the crop of poultry. Pancreatin digestion was carried out in dialysis tubing, with a ratio of about 1 : 25 (v/v) between the digesta and dialysing medium, to simulate gradient absorption from the duodenum. The feed: water ratio was kept within physiological limits and a constant proportion of feed weight to digestive enzymes was maintained. There was a linear response to increasing dosages of phytase up to 1000 phytase units (FTU)/kg feed, and to increasing phosphate concentration in feeds. in vivo validation was performed with growing torkeys (1-3 weeks) fed on diets containing 12 g Ca/kg and 0,500 or 1000 FTU phytase/kg in a factorial arrangement with 0, 1,2 or 3 g supplemental phosphate/kg (from KH,PO& After a simple transformation (variablelin vitro P = f (in vitro P)), amounts of P hydrolysed from feed samples by in vitvo digestions correlated with 3-week body-weight gain ( R 0.986, P c O*OOOl), toe ash (R 0-952, P < O.OOOl), feed intake (R 0-994, P c 0.0001) and feed efficiency (R 0.992, P < O*OOOl). The dephosphorylating ability of phytase in vitro was significantly enhanced (P<OO5) by the addition of acid phosphatase. Fungal acid protease and Aspergifhs niger cellulase also enhanced the dephosphorylation process in vitro.

Effect of Citric Acid and Phytase on Growth Performance and Mineralization of Labeo rohita Juveniles Fed Soybean Meal Based Diet

“…Among these organic acids, citric acid (CA), due to its unique flavor and high buffering capacity, has been extensively used for diet acidification (Hossain et al, 2007). Its efficacy to dephosphorylate the phytate in vitro has also been reported (Zyla et al, 1995). Citric acid supplementation resulted in improved P contents in the scute of Huso huso fed on plant meal based diet (Khajepour and Hosseini, 2011;.…”

Necrotic enteritis: Effect of barley, wheat and corn diets on proliferation of Clostridium perfringens type A

“…In vitro digestion of the diets was performed according to previously published methods (Bedford & Classen, 1993;Zyla et al 1995), with minor modifications. All in vitro digestion steps were carried out at 40°C to simulate more closely avian body temperature, using a waterjacketed incubator (Forma Scientific Inc., Marietta, OH, USA) customized with bars that rotated the tubes horizontally at 19 r.p.m.…”

Effects of dietary propionic acid, sodium citrate, and phytase on growth performance, mineral digestibility, and tibia properties in broilers

“…Using citric acid has increased phytate dephosphorylation in vitro (Zyla et al 1995) and increased phytate-P utilization in broilers diet and reduced available P requirement by about 0.10% (Boling et al 2001). Esmaeilipour et al (2011) observed that citric acid supplementation to wheat-soybean meal-based diet (low in P) increases the P retention in broilers.…”