Effect of phytase addition and dietary calcium and phosphorus levels on plasma metabolites and ileal and total-tract nutrient digestibility in pigs1,2,3,4

Abstract

Two experiments were conducted to determine the effect of phytase on plasma metabolites and AA and energy digestibility in swine. In Exp. 1, eight barrows (surgery BW = 52 kg) were fitted with steered ileocecal cannulas. The experiment was a Latin rectangle and the treatments were 1) corn-soybean meal diet adequate in Ca and P (0.5% Ca, 0.19% available P [aP]), 2) corn-soybean meal diet with reduced Ca and P (0.4% Ca, 0.09% aP), 3) Diet 1 with 500 phytase units/kg, or 4) Diet 2 with 500 phytase units/kg. Pigs were fed twice daily to a total daily energy intake of 2.6 x maintenance (106 kcal of ME/kg of BW(0.75)). For each ileal digesta sample, digesta samples were collected for two 24-h periods and combined for each pig. The combination of supplementing with phytase and decreasing the concentration of dietary Ca and P increased average ileal AA (P < 0.02), starch (P < 0.02), GE (P < 0.04), and DM (P < 0.03) digestibilities. In Exp. 2, a feeding challenge was conducted with barrows (eight per treatment; average BW of 53 kg). The treatments consisted of a corn-soybean meal diet or corn-soybean meal diet + 500 phytase units per kilogram of diet. In the diet with no phytase, Ca and aP were at 0.50% and 0.19%, respectively, and, in the diet with phytase, Ca and aP were each decreased by 0.12%. A catheter was surgically inserted into the anterior vena cava of each pig 6 d before the start of the feeding challenge. The barrows were penned individually, and the diets were fed for 3 d before the challenge. The pigs were held without feed for 16 h, and blood samples were obtained at -60, -30, and 0 min before the pigs were fed (2% of BW). Blood samples were then collected at 10, 20, 30, 40, 50, 60, 75, 90, 105, 120, 150, 180, 210, 240, 270, and 300 min after feeding. Glucose area under the response curve and plasma glucose, insulin, urea N, and total alpha-amino N concentrations were increased (P < 0.05) in pigs fed the diet with reduced Ca and P and the phytase addition. Area under the response curve for insulin, urea N, and total alpha-amino N; insulin:glucose; and plasma NEFA concentration, clearance, and half-life were not affected by diet. In conclusion, the combination of Ca and P reduction and phytase addition increased nutrient and energy digestibility in diets for pigs and increased plasma concentrations of glucose, insulin, urea N, and alpha-amino N.

Phytate degradation, intestinal microbiota, microbial metabolites and immune values are changed in growing pigs fed diets with varying calcium–phosphorus concentration and fermentable substrates

“…In the present study, the effect of dietary CaP supply by adding different amounts of monocalcium phosphate has been studied. The increase in ATTD of P by adding a higher amount of dietary inorganic P was expected and is in agreement with other studies(Johnston et al, 2004;Stein, Kadzere, Kim, & Miller, 2008), and thereby increasing P availability for the microbes. However, the P digestibility might be negatively affected due to the formation of insoluble Ca-InsP 6 complexes and the entailed limited efficiency of mucosal phytase, in particular in the proximal gut.…”

Estimating equivalency values of microbial phytase for amino acids in growing and finishing pigs fitted with steered ileo-cecal valve cannulas

“…They estimated that 500 U of phytase added per kilogram of diet to a 10% CP diet could replace 1.01 percentage units of CP. Johnston et al (2004) observed an improvement in AA AID when phytase was added to the diet and dietary Ca and P concentrations were reduced but observed no effect of phytase on N AID. Variations in phytase equivalency values for CP reported in recent reports (reviewed by Adeola and Sands, 2003) occur because of differences in the basal CP content of the diet, differences in the concentration of phytate P and inorganic P in the diet, differences in the Ca:P ratio, and differences in the grain feedstuffs used in the basal diets.…”

“…Kemme et al (1995) reported an increase in ileal digestibility of AA, and Jongbloed et al (1995) and Christensen and Nielsen (1995) demonstrated an increase in apparent total tract digestibility (ATTD) of N. However, Lantzsch and Drochner (1995) showed no improvement in N digestibility when microbial phytase was added to the diets of breeding sows. More recently, Johnston et al (2004) reported a 4.4% increase in average AA digestibility, when 500 U/kg of phytase were added and Ca and P levels were each reduced by 0.10 percentage units. However, in a review, Adeola and Sands (2003) caution against the use of an equivalency value of microbial phytase from AA due to inconsistencies in the literature.…”

Nutrient utilization and manure P excretion in growing pigs fed corn‐barley‐soybean based diets supplemented with microbial phytase

“…2005). Johnston et al . (2004) fed a diet with available P reduced by 0.12% units to growing pigs, and concluded that the combination of P reduction and phytase addition increased nutrient digestibility.…”

“…1997; Sands et al . 2001; Johnston et al . 2004) and pea‐containing diets supplemented with enzyme (Nyachoti et al .…”