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

The present study assessed effects of diets containing varying calcium-phosphorus (CaP) concentration and fermentable substrates on digestibility of diets, intestinal microbiota and immune system using 32 crossbred pigs (initial BW 54.7 kg). In a 2 × 2 factorial arrangement, pigs were fed either a corn-soybean meal (CSB) or corn-field pea (CFP) diet with either low [-] (4.4 g Ca/kg; 4.2 g total P/kg) or high [+] (8.3 g Ca/kg; 7.5 g total P/kg; supplemented with monocalcium phosphate) CaP content for a period of 9 weeks. In week 8, blood samples were taken, and at the end of the trial, all pigs were euthanized to collect digesta and mesenteric lymphoid tissue. Apparent total tract digestibility (ATTD) of P was greater (p < 0.05) for pigs fed the CaP+ and CFP diets than CaP- and CSB diets. The myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6 ) concentration in jejunal digesta was higher (p < 0.05) for CaP+ than in CaP- fed pigs. In addition, caecal and faecal InsP5 isomer concentration were greater (p < 0.05) for CSB than CFP diets. In the caecum, gene copy numbers of saccharolytic bacteria, such as Eubacterium rectale and Roseburia spp., as well as SCFA concentration were higher (p < 0.05) for CaP+ than CaP- diets. In particular, innate immune cell numbers, such as natural killer cells, dendritic cells, monocytes and neutrophils, were greater (p < 0.05) for CaP+ than CaP- fed pigs. Diets high in CaP resulted in higher abundance of potential beneficial bacteria and might promote the first line of defence enhancing the activation of the cellular adaptive immune response, thereby possibly decreasing the risk for intestinal disturbances. These results strongly suggest that both, CaP supply and dietary ingredients differing in fermentability, may beneficially affect gut health through increase in SCFA-producing bacteria and/or bacteria with anti-inflammatory properties.

Heyer CME ，Schmucker S ，Burbach K ，Weiss E ，Eklund M ，Aumiller T ，Capezzone F ，Steuber J ，Rodehutscord M ，Hoelzle LE ，Seifert J ，Mosenthin R ，Stefanski V ... -  《-》

Effect of dietary calcium concentration and exogenous phytase on inositol phosphate degradation, mineral digestibility, and gut microbiota in growing pigs.

Variations in the dietary Ca concentration may affect inositol phosphate (InsP) degradation, and thereby, P digestibility in pigs. This study assessed the effects of dietary Ca concentration and exogenous phytase on InsP degradation, nutrient digestion and retention, blood metabolites, and microbiota composition in growing pigs with ileal cannulation. In a completely randomized row-column design with four periods, eight ileal-cannulated barrows (initial body weight 27 kg) were fed four corn-soybean- and rapeseed meal-based diets containing 5.5 or 8.5 g Ca/kg dry matter (DM), with or without 1,500 FTU of an exogenous hybrid-6-phytase/kg diet. No mineral P was added and the P concentration in the feed was 4.8 g P/kg DM. Prececal InsP6 disappearance in pigs fed diets containing exogenous phytase was lower (P = 0.022) with additional Ca than without. Concentrations of InsP2-4 isomers and myo-inositol in the distal ileal digesta and prececal P digestibility were greater (P < 0.001) with exogenous phytase than without exogenous phytase. In feces, InsP6 disappearance was lower (P < 0.002) and concentration of InsP5 and InsP4 isomers was higher (P ≤ 0.031) with additional Ca compared to without additional Ca. The prececal amino acid digestibility, energy digestibility, and hindgut disappearance of energy did not differ. The Shannon diversity index of the microbiota in the distal ileal digesta and feces was similar among the diets but was lower in the distal ileal digesta than in the feces (P < 0.001). Permutation analysis of variance revealed no dietary differences between the bacterial groups within the ileal digesta and fecal samples (P > 0.05). In conclusion, additional Ca reduced the effect of exogenous phytase on prececal InsP6 degradation. Endogenous InsP degradation was impaired by additional Ca only in the hindgut but the abundance of bacterial genera in feces was not affected.

Klein N ，Sarpong N ，Melzer T ，Feuerstein D ，Heyer CME ，Camarinha-Silva A ，Rodehutscord M ... -  《-》

Effect of dietary calcium source, exogenous phytase, and formic acid on inositol phosphate degradation, mineral and amino acid digestibility, and microbiota in growing pigs.

The choice of the calcium (Ca) source in pig diets and the addition of formic acid may affect the gastrointestinal inositol phosphate (InsP) degradation and thereby, phosphorus (P) digestibility in pigs. This study assessed the effects of different Ca sources (Ca carbonate, Ca formate), exogenous phytase, and chemical acidification on InsP degradation, nutrient digestion and retention, blood metabolites, and microbiota composition in growing pigs. In a randomized design, 8 ileal-cannulated barrows (24 kg initial BW) were fed 5 diets containing Ca formate or Ca carbonate as the only mineral Ca addition, with or without 1,500 FTU/kg of an exogenous hybrid 6-phytase. A fifth diet was composed of Ca carbonate with phytase but with 8 g formic acid/kg diet. No mineral P was added to the diets. Prececal InsP6 disappearance and P digestibility were lower (P ≤ 0.032) in pigs fed diets containing Ca formate. In the presence of exogenous phytase, InsP5 and InsP4 concentrations in the ileal digesta were lower (P ≤ 0.019) with Ca carbonate than Ca formate. The addition of formic acid to Ca carbonate with phytase diet resulted in greater (P = 0.027) prececal InsP6 disappearance (87% vs. 80%), lower (P = 0.001) InsP5 concentration, and greater (P ≤ 0.031) InsP2 and myo-inositol concentrations in the ileal digesta. Prececal P digestibility was greater (P = 0.004) with the addition of formic acid compared to Ca carbonate with phytase alone. Prececal amino acid (AA) digestibility of some AA was greater with Ca formate compared to Ca carbonate but only in diets with phytase (P ≤ 0.048). The addition of formic acid to the diet with Ca carbonate and phytase increased (P ≤ 0.006) the prececal AA digestibility of most indispensable AA. Exogenous phytase affected more microbial genera in the feces when Ca formate was used compared to Ca carbonate. In the ileal digesta, the Ca carbonate diet supplemented with formic acid and phytase led to a similar microbial community as the Ca formate diets. In conclusion, Ca formate reduced prececal InsP6 degradation and P digestibility, but might be of advantage in regard to prececal AA digestibility in pigs compared to Ca carbonate when exogenous phytase is added. The addition of formic acid to Ca carbonate with phytase, however, resulted in greater InsP6 disappearance, P and AA digestibility values, and changed ileal microbiota composition compared to Ca carbonate with phytase alone.

Klein N ，Sarpong N ，Feuerstein D ，Camarinha-Silva A ，Rodehutscord M ... -  《-》

Effect of phytate, microbial phytase, fiber, and soybean oil on calculated values for apparent and standardized total tract digestibility of calcium and apparent total tract digestibility of phosphorus in fish meal fed to growing pigs.

González-Vega JC ，Walk CL ，Stein HH 《-》

Cereal grain fiber composition modifies phosphorus digestibility in grower pigs.

Increased fermentable carbohydrates (e.g., β-glucan, amylose) may increase endogenous losses including for P, and thereby reduce apparent total tract digestibility (ATTD) of P. The present study assessed effects of barley cultivars varying in fermentable starch and fiber on apparent ileal digestibility (AID) and ATTD of P, myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate; InsP6) and Ca, and standardized total tract digestibility (STTD) of P and the presence of lower inositol phosphates (InsP) compared to wheat. In a 6 (period) × 5 (diet) Youden square, seven ileal-cannulated barrows (initial BW, 27.7 kg) were fed diets containing 80% of one of five cereal grains differing in amylose, β-glucan, and fiber content: 1) high-fermentable, high-β-glucan, hull-less barley (HFB); 2) high-fermentable, high-amylose, hull-less barley (HFA); 3) moderate-fermentable, hull-less barley (MFB); 4) low-fermentable, hulled barley (LFB); and 5) low-fermentable, Canadian Western Red Spring wheat (LFW). On dry matter (DM) basis, cereal grains contained between 0.32% to 0.53% total P and 0.24% to 0.50% InsP6-P. The InsP6-2-P was calculated as the sum of all detected InsP-P (InsP6-P to InsP2-P) in the sample. The P release of degraded InsP-P was calculated by using the following equation: sum InsP6-2-Pdiet (g/kg DM) × (AID or ATTD sum InsP6-2-P (%)/ 100). Data were analyzed using a mixed model with diet as fixed effect, and pig and period as random effects. On DM basis, diets contained 41.4% to 50.6% starch, 0.88% to 8.54% β-glucan, 0.81% to 0.89% total P, and 0.19% to 0.35% InsP6-P. The MFB, LFB, and LFW had greater (P < 0.05) diet AID of P than HFB and HFA, and MFB had greater (P < 0.05) diet ATTD and STTD of P than HFB. The ATTD of InsP6-P was greater (P < 0.05) for HFB than LFB and the ATTD of the sum InsP6-2-P was greater (P < 0.05) for HFB and HFA than LFB. Total tract P release was greater (P < 0.001) for HFB, HFA, and LFW than MFB and LFB. The LFW had greater (P < 0.05) ATTD of Ca than LFB. Diet β-glucan content was not correlated with STTD of P (R2 = 0.03) or ATTD of InsP6 (R2 = 0.05). In conclusion, cereal grains high in fermentable fiber, e.g., amylose and β-glucans included in specific hull-less barley cultivars, had lower diet AID, ATTD, and STTD of P, but greater ATTD of InsP6-P and sum InsP6-2-P. Carbohydrate fermentation, thus, results in greater total tract P release from InsP-P hydrolysis.

Heyer CME ，Fouhse JM ，Vasanthan T ，Zijlstra RT ... -  《-》