Phosphorus bioavailability, growth performance, and nutrient balance in pigs fed high available phosphorus corn and phytase.

Abstract

Three experiments were conducted to evaluate P bioavailability, growth performance, and nutrient balance in pigs fed high available P (HAP) corn with or without phytase. The bioavailability of P in normal and HAP corn relative to monosodiumphosphate (MSP) for pigs was assessed in Exp. 1. In a randomized complete block design, 96 pigs (average initial BW 9.75 kg) were fed eight diets for 28 d. The reference and test diets were formulated by adding P as MSP, HAP, or normal corn at 0, 0.75, or 1.5 g/kg to a corn-starch-soybean meal basal diet (2.5 g/kg P) at the expense of cornstarch. Plasma inorganic P concentration responded linearly (P < 0.05) to supplemental P intake. Estimates of P bioavailability from HAP andnormal corn when plasma P was regressed on supplemental P intake were 46 and 33%, respectively. In Exp. 2 and 3, pigs were fed corn-soybean meal-based diets containing HAP corn or normal corn and 0 or 600 units of phytase per kilogram in a 2 x 2 factorial arrangement (two corn sources and two levels of phytase). In Exp. 2, 48 crossbred pigs (barrow:gilt, 1:1) averaging 9.25 kg were used to evaluate growth performance. There were no detectable interactions between corn source and phytase for any of the performance criteria measured. Pigs receiving normal corn had the lowest (P < 0.05) BW and rate of gain. Feed efficiency was lower (P < 0.05) in pigs fed normal compared with those fed the HAP corn phytase-supplemented diet. In Exp. 3, 24 crossbred barrows averaging 14.0 kg were used to evaluate nutrient digestibility. There were no detectable interactions between corn and phytase for any of the N and Ca balance criteria. Nitrogen and Ca retention were improved in pigs receiving HAP corn with phytase (P < 0.05). Retention and digestibility of P was lowest (P < 0.01) for pigs on normal corn diet without phytase. The percentage of P digested and retained was improved and fecal P excretion lowered (P < 0.05) by feeding HAP corn. The results of this study indicate that the bioavailability and balance of P in HAP corn is superior to that of normal corn. The addition of 600 phytase units (Natuphos 600, BASF) to HAP corn-based diets further improved P digestibility and reduced P excretion in pigs.

Effect of microbial phytase and diet fermentation on ileal and total tract digestibility of nutrients and energy in growing pigs

“…Phytase supplementation significantly reduced faecal P excretion in both dry and liquid fermented diets (Table 6) and similar results were reported by other authors (Näsi, 1990;Cromwell et al, 1995;Sands et al, 2001). However, the effect of phytase on total P excretion may be diverse, depending on the dietary concentration of available P. In our previous study using P-adequate diets we found that the phytase-induced reduction in faecal P excretion was partly counteracted by an increased urinary P excretion.…”

“…The results of experiments studying the effect of phytase on Ca digestibility in pigs are controversial. Some reports showed no effect (Yi et al, 1996;Harper et al, 1997;Sands et al, 2001) while others showed that phytase increased both ileal (Traylor et al, 2001) and total tract (Kemme et al, 1997) Ca digestibility. There are even studies demonstrating a greater effect of added phytase on Ca digestibility than on P digestibility (Johnston et al, 2004).…”

“…total N (Sands et al, 2001;Walz and Pallauf, 2003;Pomar et al, 2008). The reasons for these ambiguous results are not known.…”

Body weight gain and nutrient utilization in starter pigs that are liquid-fed high-moisture corn-based diets supplemented with phytase

“…Upon entering the small intestine, phytase is quickly deactivated by rising pH or degraded by intestinal proteases (Kemme et al 2006). Values for P digestibility in the current trial are similar to those obtained in a previous trial that fed diets containing low-phytate corn to starter pigs (Sands et al 2001). The lack of a significant response in P digestibility with the addition of phytase during Phase II in the current trial, however, conflicts with previous observations in studies where pigs were fed dry cornand soybean-meal-based diets (Han et al 1997;Zhang et al 2000).…”

Animal production for efficient phosphate utilization: from optimized feed to high efficiency livestock

“…Transgenics has been used to develop low-phytate plants such as soybean meal [37], high available P corn [38] and canola seeds expressing a phytase gene [39] for inclusion in swine and poultry diets. Hill et al [37] fed growing pigs a diet containing low-phytate corn and soybean meal, and the total P digestibility increased from 34 to 48% compared to a conventional corn-soybean meal diet.…”