Exogenous phytase and xylanase exhibit opposing effects on real-time gizzard pH in broiler chickens

Production of fungal phytases in solid state fermentation and potential biotechnological applications

Phytases are important enzymes used for eliminating the anti-nutritional properties of phytic acid in food and feed ingredients. Phytic acid is major form of organic phosphorus stored during seed setting. Monogastric animals cannot utilize this phytate-phosphorus due to lack of necessary enzymes. Therefore, phytic acid excretion is responsible for mineral deficiency and phosphorus pollution. Phytases have been reported from diverse microorganisms, however, fungal phytases are preferred due to their unique properties. Aspergillus species are the predominant producers of phytases and have been explored widely as compared to other fungi. Solid-state fermentation has been studied as an economical process for the production of phytases to utilize various agro-industrial residues. Mixed substrate fermentation has also been reported for the production of phytases. Physical and chemical parameters including pH, temperature, and concentrations of media components have significantly affected the production of phytases in solid state fermentation. Fungi produced high levels of phytases in solid state fermentation utilizing economical substrates. Optimization of culture conditions using different approaches has significantly improved the production of phytases. Fungal phytases are histidine acid phosphatases exhibiting broad substrate specificity, are relatively thermostable and protease-resistant. These phytases have been found effective in dephytinization of food and feed samples with concomitant liberation of minerals, sugars and soluble proteins. Additionally, they have improved the growth of plants by increasing the availability of phosphorus and other minerals. Furthermore, phytases from fungi have played an important roles in bread making, semi-synthesis of peroxidase, biofuel production, production of myo-inositol phosphates and management of environmental pollution. This review article describes the production of fungal phytases in solid state fermentation and their biotechnological applications.

Accentuating the positive and eliminating the negative: Efficacy of TiO2 as digestibility index marker for poultry nutrition studies

Inert digestibility index markers such as titanium dioxide are universally accepted to provide simple measurement of digestive tract retention and relative digestibility in poultry feeding trials. Their use underpins industry practice: specifically dosing regimens for adjunct enzymes added to animal feed. Among these, phytases, enzymes that degrade dietary phytate, inositol hexakisphosphate, represent a billion-dollar sector in an industry that raises ca. 70 billion chickens/annum. Unbeknown to the feed enzyme sector, is the growth in cell biology of use of titanium dioxide for enrichment of inositol phosphates from extracts of cells and tissues. The adoption of titanium dioxide in cell biology arises from its affinity under acid conditions for phosphates, suggesting that in feeding trial contexts that target phytate degradation this marker may not be as inert as assumed. We show that feed grade titanium dioxide enriches a mixed population of higher and lower inositol phosphates from acid solutions. Additionally, we compared the extractable inositol phosphates in gizzard and ileal digesta of 21day old male Ross 308 broilers fed three phytase doses (0, 500 and 6000 FTU/kg feed) and one inositol dose (2g/kg feed). This experiment was performed with or without titanium dioxide added as a digestibility index marker at a level of 0.5%, with all diets fed for 21 days. Analysis yielded no significant difference in effect of phytase inclusion in the presence or absence of titanium dioxide. Thus, despite the utility of titanium dioxide for recovery of inositol phosphates from biological samples, it seems that its use as an inert marker in digestibility trials is justified-as its inclusion in mash diets does not interfere with the recovery of inositol phosphates from digesta samples.

Influence of Dietary Phytase Inclusion Rates on Yolk Inositol Concentration, Hatchability, Chick Quality, and Early Growth Performance

The aim of this study was to determine the influence of dietary phytase in breeder hens on yolk nutrients, hatchability, chick quality, and growth rate of their progeny, and their subsequent performance to 42 d post-hatch when fed diets with the same phytase concentrations. Breeder hens (n = 216) were divided into 3 groups receiving nutrient-adequate diets with reduced calcium (Ca) and phosphorus (P) (by 0.16% and 0.15%, respectively), supplemented with either 500, 1500, or 4500 FTU/kg phytase from 27 to 50 weeks of age. Eggs were collected at 38 weeks of age and incubated. On the day of hatch, the chick quality and hatchability were determined, and 18 chicks/group were euthanized for yolk sac collection and the determination of inositol and glycerol concentrations. The remaining chicks were divided into three groups, receiving different diets with reduced Ca and P (by 0.16% and 0.15%, respectively), supplemented with 0, 500, or 1500 FTU/kg phytase to 42 d post-hatch. Increasing the phytase concentration in the breeder hen diet linearly (p < 0.05) increased the number of early embryo deaths and decreased the number of late deaths and pips. The inositol concentration in the yolk sac at day of hatch increased (quadratic; p < 0.05) as the phytase dose increased in the breeder hen diet. The breeder hen diet (p < 0.05) influenced the body weight (BW), feed intake (FI), and feed conversion ratio (FCR) up to 21 days of age. The supplementation of breeder hen diets with 1500 FTU/kg phytase increased the concentration of sodium (Na), magnesium (Mg), potassium (K), manganese (Mn), and zinc (Zn) in the yolk sac. The inclusion of phytase doses up to 4500 FTU/kg appeared to influence embryo mortality, chick feed intake, and BW gain to 21 days and the FCR throughout the entire production phase.

Nutritional and Functional Roles of Phytase and Xylanase Enhancing the Intestinal Health and Growth of Nursery Pigs and Broiler Chickens

This review paper discussed the nutritional and functional roles of phytase and xylanase enhancing the intestinal and growth of nursery pigs and broiler chickens. There are different feed enzymes that are currently supplemented to feeds for nursery pigs and broiler chickens. Phytase and xylanase have been extensively studied showing consistent results especially related to enhancement of nutrient digestibility and growth performance of nursery pigs and broiler chickens. Findings from recent studies raise the hypothesis that phytase and xylanase could play functional roles beyond increasing nutrient digestibility, but also enhancing the intestinal health and positively modulating the intestinal microbiota of nursery pigs and broiler chickens. In conclusion, the supplementation of phytase and xylanase for nursery pigs and broiler chickens reaffirmed the benefits related to enhancement of nutrient digestibility and growth performance, whilst also playing functional roles benefiting the intestinal microbiota and reducing the intestinal oxidative damages. As a result, it could contribute to a reduction in the feed costs by allowing the use of a wider range of feedstuffs without compromising the optimal performance of the animals, as well as the environmental concerns associated with a poor hydrolysis of antinutritional factors present in the diets for swine and poultry.

Phytase dose-dependent response of kidney inositol phosphate levels in poultry

Phytases, enzymes that degrade phytate present in feedstuffs, are widely added to the diets of monogastric animals. Many studies have correlated phytase addition with improved animal productivity and a subset of these have sought to correlate animal performance with phytase-mediated generation of inositol phosphates in different parts of the gastro-intestinal tract or with release of inositol or of phosphate, the absorbable products of phytate degradation. Remarkably, the effect of dietary phytase on tissue inositol phosphates has not been studied. The objective of this study was to determine effect of phytase supplementation on liver and kidney myo-inositol and myo-inositol phosphates in broiler chickens. For this, methods were developed to measure inositol phosphates in chicken tissues. The study comprised wheat/soy-based diets containing one of three levels of phytase (0, 500 and 6,000 FTU/kg of modified E. coli 6-phytase). Diets were provided to broilers for 21 D and on day 21 digesta were collected from the gizzard and ileum. Liver and kidney tissue were harvested. Myo-inositol and inositol phosphates were measured in diet, digesta, liver and kidney. Gizzard and ileal content inositol was increased progressively, and total inositol phosphates reduced progressively, by phytase supplementation. The predominant higher inositol phosphates detected in tissues, D-and/or L-Ins(3,4,5,6)P4 and Ins(1,3,4,5,6)P5, differed from those (D-and/or L-Ins(1,2,3,4)P4, D-and/or L-Ins(1,2,5,6)P4, Ins(1,2,3,4,6)P5, D-and/or L-Ins(1,2,3,4,5)P5 and D-and/or L-Ins(1,2,4,5,6)P5) generated from phytate (InsP6) degradation by E. coli 6-phytase or endogenous feed phytase, suggesting tissue inositol phosphates are not the result of direct absorption. Kidney inositol phosphates were reduced progressively by phytase supplementation. These data suggest that tissue inositol phosphate concentrations can be influenced by dietary phytase inclusion rate and that such effects are tissue specific, though the consequences for physiology of such changes have yet to be elucidated.

Effect of phytase supplementation on plasma and organ myo-inositol content and erythrocyte inositol phosphates as pertaining to breast meat quality issues in chickens

‘Woody breast’ (WB) and ‘white striping’ in broiler meat is a global problem. With unknown etiology, WB negatively impacts bird health, welfare and is a significant economic burden to the poultry industry. New evidence has shown that WB is associated with dysregulation in systemic and breast muscle-oxygen homeostasis, resulting in hypoxia and anaemia. However, it has been observed that phytase (Quantum Blue (QB) a modified, E. coli-derived 6-phytase) super dosing can reverse dysregulation of muscle-oxygen homeostasis and reduces WB severity by ~5%. The objective of this study was to assess whether levels of Ins(1,3,4,5,6)P5, the main allosteric regulator of haemoglobin, are influenced by changes in plasma myo-inositol arising from super dosing with phytase. To enable this, methods suitable for measurement of myo-inositol in tissues and inositol phosphates in blood were developed. Data were collected from independent trials, including male Ross 308 broilers fed low and adequate calcium/available phosphate (Ca/AvP) diets supplemented with QB at 1,500 phytase units (FTU)/kg, which simultaneously decreased gizzard InsP6 (P<0.001) and increased gizzard myo-inositol (P<0.001). Similarly, male Cobb 500 broiler chicks fed a negative control (NC) diet deficient in AvP, Ca and sodium or diet supplemented with the QB phytase at 500, 1000 or 2,000 FTU/kg increased plasma (P<0.001) and liver (P=0.007) myo-inositol of 18d-old birds at 2,000 FTU/kg. Finally, QB supplementation of Cobb 500 breeder flock diet at 1,250 FTU/kg increased blood myo-inositol (P<0.001) and erythrocyte Ins(1,3,4,5,6)P5 (P=0.011) of their 1d-old hatchlings. These data confirmed the ability of phytase to modulate inositol phosphate pathways by provision of metabolic precursors of important signalling molecules. The ameliorations of WB afforded by super doses of phytase may include modulation of hypoxia pathways that also involve inositol signalling molecules. Elevations of erythrocyte Ins(1,3,4,5,6)P5 by phytase supplementation may enhance systemic oxygen carrying capacity, an important factor in the amelioration of WB and WS myopathy.

Interaction between xylanase and a proton pump inhibitor on broiler chicken performance and gut function

Three hundred thirty-six Ross 308 male broiler chicks were used in a 21-d study to explore performance and gut function when treated with a proton pump inhibitor (PPI; 0 or 89 mg/kg) in a 2 × 2 factorial arrangement with a xylanase (Xyl; 0 or 0.1 g/kg) to determine if the beneficial activity of arabinoxylan (AX) depolymerisation, through arabinoxylo-oligosaccharides (AXOS) production, starts in the upper gastrointestinal tract. Treatment with the PPI started from d 14, and by d 21 animal performance had deteriorated (P < 0.001). An interaction was observed between PPI and Xyl for feed conversion ratio (FCR) (P < 0.05), whereby the combination reduced the negative effect of PPI on FCR. Application of PPI raised digesta pH in the gizzard and caecum (P < 0.05), increased protein concentrations in the lower gut (P < 0.05) and reduced intake of digestible nutrients (P < 0.05). Caecal concentrations of indole, p-cresol, ammonia and the ratio of total volatile fatty acid (VFA) to butyric acid were increased with PPI (P < 0.05), indicating enhanced protein fermentation. Xylanase activity in the digesta were greatest in the caeca, especially when Xyl was supplemented (P < 0.001). The concentration of total soluble AX was greater in the gizzard and ileal digesta with Xyl supplementation (P < 0.05), supporting the depolymerisation action of xylanase even under acidic conditions. These data suggest xylanase may function in the gizzard even though pH is not optimal for activity and emphasises the importance of chlorohydric acid secretions in ensuring overall optimum gut function. AX depolymerisation benefits animal performance although it is still unknown how the AXOS produced with xylanase supplementation in the upper gastrointestinal tract influence the microbial populations and overall gut functionality.

Application of Creep Feed and Phytase Super-Dosing as Tools to Support Digestive Adaption and Feed Efficiency in Piglets at Weaning

A total of 64 piglets were used in a 35-day study to evaluate whether creep feeding piglets on the sow or super-dosing phytase to piglets post-weaning can be used as a tool to reduce stress and support adaption to weaning. Treatments consisted of creep or no creep feed being offered pre-weaning and with or without phytase supplementation at 2000 FTU/kg post-weaning. Blood samples were collected from eight piglets per treatment on days 0 (weaning), 7 and 21 post-weaning to determine plasma cortisol and myo-inositol concentrations. Four piglets per treatment (n = 16) were administered Heidelberg pH capsules 1 week prior to weaning, on the day of weaning, as well as 7 days and 21 days post-weaning, with readings monitored over a 3 h period. In the first week post-weaning, creep-fed piglets had higher daily gains (0.23 vs. 0.14 kg/d, p < 0.05) and a lower feed conversion ratio (FCR, 0.99 vs. 1.35, p < 0.01), compared to non-creep-fed pigs. At 21 days post-weaning, irrespective of creep feed, phytase supplementation reduced FCR (1.10 vs. 1.18, p = 0.05) of piglets. Average real-time stomach pH was lower in creep-fed piglets at 1 week prior to weaning (pH 3.2 vs. 4.6, p < 0.001) and on day of weaning (pH 3.1 vs. 3.7, p < 0.01). Following weaning, phytase reduced average stomach pH of piglets at days 7 (pH 2.6 vs. 3.3, p < 0.001) and 21 (pH 2.2 vs. 2.6, p < 0.01). Both cortisol and myo-inositol concentrations in plasma decreased with age; however, cortisol levels were unaffected by either treatment. Plasma myo-inositol concentrations were higher in creep-fed piglets at day of weaning (p < 0.05) and with phytase super-dosing on day 21 (p < 0.001). These findings demonstrate that both creep feeding and phytase super-dosing are useful practices to encourage better adaption to weaning and support piglet performance. This response was not related to reduced stress in piglets, as determined by cortisol levels, but instead appears to relate to improved gastric conditions for digestion, phytate degradation and myo-inositol provision in piglets.

Growth performance, real-time gizzard pH and calcium solubility in the gut of broiler chickens is dependent on the interaction between dietary calcium concentration and limestone particle size

1.The purpose of this study was to determine the effect of limestone particle size and dietary Ca concentration on performance, real-time gizzard pH, and Ca and P solubility in the gastrointestinal tract of 21d broiler chickens.2. A total of 576, one-day-old Ross 308 male broilers were randomly allocated among 4 treatments, with 8 replicate pens, and 18 birds per pen. Treatments were arranged as a 2 × 2 factorial consisting of two particle sizes of limestone (coarse, CL, 1200 µm; fine, FL, 44 µm) and two Ca concentrations (9.6 or 6.0 g/kg). On d 19 and 20, four birds per treatment were administered Heidelberg pH capsules and readings monitored for 3 h.3. Reducing Ca concentration from 9.6 to 6.0 g/kg had no effect on d 21 weight gain or FCR of birds fed CL; however, feeding FL at 9.6 g/kg Ca increased weight gain by 10% and reduced FCR by 5% compared to FL at 6.0 g/kg Ca (P < 0.001).4. Average gizzard pH readings ranged from pH 0.67 to 3.01 across all treatments. Birds fed CL at 6.0 g/kg Ca had lower average gizzard pH compared to birds fed 9.6 g/kg Ca, while birds fed FL at 6.0 g/kg Ca had higher gizzard pH than birds fed CL at both Ca concentrations, but was comparable to birds fed FL at 9.6 g/kg Ca (P < 0.001).5. For birds fed CL at 6.0 g/kg Ca, soluble Ca in the gizzard was approximately 40% lower (P < 0.05) than all other treatments, and reduced by 44% (P < 0.05) in the small intestine compared with birds fed FL at 6.0 g/kg Ca.6. These findings demonstrated that the effect of Ca concentration on gizzard pH, Ca solubility and broiler performance was dependent on limestone particle size and suggested that solubility per se had little relevance to performance.

Effect of two phytases at two doses on performance and phytate degradation in broilers during 1-21 days of age

The effect of two microbial phytases at two dose-levels on performance and apparent ileal digestibility (AID) of nutrients in broilers fed European-type diets was studied. A total of 1,200 d-old Ross 308 male broilers were randomly assigned to 5 treatments with 30 birds/pen and 8 pens/treatment. A nutritionally adequate positive control (PC) diet was tested against 4 experimental diets containing reduced total P, retainable P, Ca and Na as per the recommended nutritional contribution for Buttiauxella phytase (Phy B) at 1,000 FTU/kg (-1.87 g/kg, -1.59 g/kg, -1.99 g/kg and -0.4 g/kg vs. PC, respectively). Experimental diets were supplemented with Phy B at 500 FTU/kg or 1,000 FTU/kg, or Citrobacter phytase (Phy C) at 1,000 FTU/kg or 2,000 FTU/kg. Diets were based on corn, soybean meal, rapeseed meal and sunflower meal and formulated by phase (starter 1–10 d, grower 11–21 d) in crumbled or pelleted form. Overall (d 1–21), at 1,000 FTU/kg, birds fed Phy C exhibited lower BWG (-2.7%), FI (-3.4%) and tibia ash (-2.2%) vs. PC (P < 0.05), and reduced BWG (-3.6%), FI (-3.9%) and tibia ash (-1.8%) vs. Phy B (P < 0.05). Phy B at 1,000 FTU/kg and Phy C at 2,000 FTU/kg maintained performance equivalent to the PC. Digestibility of Ca did not differ among phytase treatments but at 1,000 FTU/kg AID P was greater with Phy B than Phy C (72.3% vs. 62.7%, P < 0.05). Ileal phytate (myo-inositol hexakisphosphate, IP6) digestibility was greatest with Phy B at 1,000 FTU/kg which was higher than Phy C at 1,000 FTU/kg (87.6 vs. 60.6%, P < 0.05). The findings indicate a higher phytate degradation rate of Phy B than Phy C at equivalent dose-level and this is correlated to the performance of the broilers.

Contrasting the effects of phytase and pure myo-inositol on the performance, digestibility, blood and egg yolk inositol levels and digestion physiology of laying hens

ABSRACT1. An experiment was designed to compare the effects of supplementing laying hen diets with phytase and myo-inositol (inositol).2. Five diets were formulated: high balanced protein (HBP - 840 mg of Dlys/hen/day), HBP with inositol (HBP+I - 0.16%), reduced balance protein (RBP - 672 mg of Dlys/hen/day), RBP with inositol (RBP+I - 0.16%) and RBP with phytase (RBP+P - 3000 FTU/kg).3. Laying hen production, inositol concentrations, digestive tract morphology, amino acid digestibility and intestinal inositol transporters transcript abundance were evaluated. Data were analysed with a one-way ANOVA in SAS 9.4. Contrasts were used to assess the effect of protein, inositol, phytase and phytase vs. inositol. Differences were accepted when P ≤ 0.05.4. No effect on hen-day egg production or feed efficiency was found. However, feed intake and the incidence of abnormally shaped eggs were 0.77 g/h/d and 0.17% higher, respectively, in inositol treatments. Inositol decreased egg specific gravity from 1.088 to 1.0865.5. Inositol concentration in egg yolk was similar among HBP+I, RBP+I and RBP+P, and higher than for the HBP and RBP diet groups. Both gizzard and ileal digesta were enriched in inositol in all supplemented treatments, and phytase supplementation decreased the level of IP5 and IP6 in the gizzard and ileum. Generally, neither phytase or inositol affected amino acid digestibility.6. Inositol increased transcript abundance of alkaline phosphatase in the ileum, while phytase upregulated duodenal alkaline phosphatase and SMIT1, jejunal SMIT2 and reduced ileal HMIT and SMIT1 abundance.7. In conclusion, no effect of phytase or inositol was found for laying hen production performance or amino acid digestibility, but egg quality was reduced by inositol supplementation. Inositol concentration in egg yolk was similar among supplemented treatments.

Dietary phytate has a greater anti-nutrient effect on feed conversion ratio compared to body weight gain and greater doses of phytase are required to alleviate this effect as evidenced by prediction equations on growth performance, bone ash and phytate degradation in broilers

Cobb 400, male broilers (n=4,752) were fed one of 12 diets, with 12 pens/diet and 33 birds/pen. Treatments consisted of 3 levels of phytate P (0.24, 0.345, or 0.45%) and 4 doses of phytase (0, 500, 1,000, or 2,000 phytase units (FTU)/kg). Diets were formulated with reduced Ca (0.22%), available P (0.20%), energy (80 to 120 kcal/kg), and amino acids (1 to 5%) when compared with breed requirements. Prediction equations suggested feeding dietary phytate P > 0.275, 0.295, or 0.319% reduced feed intake (FI) and body weight gain (BWG) and increased feed conversion ratio, respectively, from day 0 to 21. Supplementing phytase at 561, 1,285, or >2,000 FTU/kg resulted in the maximum FI, BWG, or feed efficiency, respectively. From day 0 to 42, maximum BWG or feed efficiency were achieved at phytate P concentrations <0.281 or 0.25%, respectively. Supplementing phytase at 449 or 2,000 FTU/kg maximized BWG or feed efficiency, respectively. Tibia ash weight, percent or Ca concentration were maximized at phytate P concentrations <0.24, 0.296, or 0.24%, respectively and phytase supplementation at 822 or >2,000 FTU/kg maximized tibia ash weight or percent respectively. In the absence of phytase, phytate (IP6) concentration in the gizzard was greatest in birds fed 0.45% phytate P and phytase supplementation between 1,132 to 1,285 FTU/kg resulted in the lowest IP6 concentration in the gizzard. There was no effect of dietary phytate P on the concentration of phytate esters (IP5 or IP4) in the gizzard, which were minimized at 1,208 FTU/kg of phytase. In the absence of phytase, the concentration of phytate ester (IP3) or inositol in the gizzard was greatest in birds fed 0.345% phytate P and phytase supplementation at ∼500 FTU/kg minimized IP3, whereas 2,000 FTU/kg maximized inositol, except in birds fed 0.45% phytate P, which was maximized at 202 FTU/kg of phytase. Prediction equations can be useful to determine the influence of phytase and phytate P on broiler performance, phytate degradation and bone ash.

Effect of phytase on intestinal phytate breakdown, plasma inositol concentrations, and glucose transporter type 4 abundance in muscle membranes of weanling pigs1

The objective of this present study was to determine the effects of phytase dosing on growth performance, mineral digestibility, phytate breakdown, and the level of glucose transporter type 4 (GLUT4) in muscle plasma membranes of weanling pigs. A total of 160 barrows were used in a randomized completely block design and assigned to 4 treatments for a 7-wk study. Depending on the feeding phase, diets differed in dietary calcium (Ca) and phosphorus (P) levels (positive control [PC]: 8 to 6.8g/kg Ca; 7.3 to 6.3 g/kg P; negative control [NC]: 5.5 to 5.2 g/kg Ca; 5.4 to 4.7 g/kg P). NC diets were supplemented with phytase at 0 (NC); 500 (NC + 500 FTU); or 2,000 FTU/kg (NC + 2,000 FTU) phytase units/kg. Blood was collected after fasting (day 48) or feeding (day 49) for measurement of plasma inositol concentrations. On day 49, 2 pigs per pen were euthanized, and duodenal and ileal digesta samples were collected to determine inositol phosphates (InsP6-2) concentrations. High phytase supplementation increased BW on days 21, 35, and 49 (P < 0.05). Over the entire feeding period, ADG, ADFI, and feed efficiency were increased by NC + 2,000 FTU compared with the other treatments (P < 0.05). Postprandial plasma inositol concentration was increased in NC + 2,000 (P < 0.01), but there was only a tendency (P = 0.06) of a higher fasting plasma inositol concentration in this group. Inositol concentrations in the portal vein plasma (day 49) were not different among treatments. Duodenal digesta InsP5 and InsP6 concentrations were similar in PC and NC, but higher in these 2 treatments (P < 0.05) than those supplemented with phytase. Phytase supplementation decreased InsP6-4, resulting in increased InsP3-2 and myo-inositol concentrations. Similar effects were found in ileal contents. Compared with NC, phytase supplementation resulted in greater cumulative InsP6-2 disappearance (93.6% vs. 72.8% vs. 25.0%, for NC + 2,000 FTU, NC + 500 FTU and NC, respectively, P < 0.01) till the distal ileum. Longissimus dorsi muscle plasma membrane GLUT4 concentration was increased by NC + 2,000 FTU (P < 0.01) compared with NC. In summary, high phytase supplementation increased growth performance of nursery pigs. The higher myo-inositol release from phytate could contribute to the increased expression of GLUT4 in muscle plasma membranes. Further investigation is needed to determine whether this is associated with enhanced cellular glucose uptake and utilization.

Response of broiler chickens to xylanase and butyrate supplementation

A 2 × 2 factorial experiment was used to evaluate the effect of xylanase and sodium butyrate supplementation on performance, intestinal fermentation, histology, and morphometry in broiler chickens. A total of 384 Ross 308 broiler chicks (1-day-old) were allocated to 4 experimental treatments: CTR (control diet), XYL (CTR diet with 16,000 BXU/kg of xylanase), BUT (CTR diet with 1 kg/t sodium butyrate), and XYL+BUT (CTR diet plus xylanase and sodium butyrate). Each treatment had 8 replicates of 12 animals. Starter and grower diets, based on wheat and soybean meal, and water were available ad libitum. Body weight gain and feed intake were measured from 0 to 42 D, and feed conversion ratio corrected for mortality (FCR) was calculated. The profile of short-chain fatty acids in the duodenum, jejunum, ileum, and ceca digesta on days 21 and 42 was analyzed in addition to the relative weights of the different portions of the gastrointestinal tract (GIT). The villus height (VH), crypt depth (CD), and villus to crypt (VH: CD) ratio from the ileal tissue on day 42 were also evaluated. Statistical comparisons were performed using a 2-way ANOVA. Xylanase supplementation improved 42-D FCR by 5 points (P = 0.006), while butyrate did not affect 42-D FCR. On day 21, birds fed butyrate had heavier total GIT (P = 0.024), duodenum (P < 0.001), and jejunum (P = 0.025). Xylanase did not influence the relative weights in any intestinal section except the crop which was smaller in xylanase supplemented birds. At day 42, the VH: CD ratio was increased with sodium butyrate (P = 0.005). Supplementation of broiler diets with xylanase improved performance but had little effect on intestinal measures, whereas sodium butyrate influenced many of the intestinal indices with no consequence on animal performance.

Quantum Blue Reduces the Severity of Woody Breast Myopathy via Modulation of Oxygen Homeostasis-Related Genes in Broiler Chickens

The incidence of woody breast (WB) is increasing on a global scale representing a significant welfare problem and economic burden to the poultry industry and for which there is no effective treatment due to its unknown etiology. In this study, using diffuse reflectance spectroscopy (DRS) coupled with iSTAT portable clinical analyzer, we provide evidence that the circulatory- and breast muscle-oxygen homeostasis is dysregulated [low oxygen and hemoglobin (HB) levels] in chickens with WB myopathy compared to healthy counterparts. Molecular analysis showed that blood HB subunit Mu (HBM), Zeta (HBZ), and hephaestin (HEPH) expression were significantly down regulated; however, the expression of the subunit rho of HB beta (HBBR) was upregulated in chicken with WB compared to healthy counterparts. The breast muscle HBBR, HBE, HBZ, and hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) mRNA abundances were significantly down regulated in WB-affected compared to normal birds. The expression of HIF-1α at mRNA and protein levels was significantly induced in breasts of WB-affected compared to unaffected birds confirming a local hypoxic status. The phosphorylated levels of the upstream mediators AKT at Ser473 site, mTOR at Ser2481 site, and PI3K P85 at Tyr458 site, as well as their mRNA levels were significantly increased in breasts of WB-affected birds. In attempt to identify a nutritional strategy to reduce WB incidence, male broiler chicks (Cobb 500, n = 576) were randomly distributed into 48 floor pens and subjected to six treatments (12 birds/pen; 8 pens/treatment): a nutrient adequate control group (PC), the PC supplemented with 0.3% myo-inositol (PC + MI), a negative control (NC) deficient in available P and Ca by 0.15 and 0.16%, respectively, the NC fed with quantum blue (QB) at 500 (NC + 500 FTU), 1,000 (NC + 1,000 FTU), or 2,000 FTU/kg of feed (NC + 2,000 FTU). Although QB-enriched diets did not affect growth performances (FCR and FE), it did reduce the severity of WB by 5% compared to the PC diet. This effect is mediated by reversing the expression profile of oxygen homeostasis-related genes; i.e., significant down regulation of HBBR and upregulation of HBM, HBZ, and HEPH in blood, as well as a significant upregulation of HBA1, HBBR, HBE, HBZ, and PHD2 in breast muscle compared to the positive control.

Sampling duration and freezing temperature influence the analysed gastric inositol phosphate composition of pigs fed diets with different levels of phytase

This experiment was conducted to determine the effects of time and freezing temperature during sampling on gastric phytate (myo-inositol [MYO] hexakisphosphate [InsP₆]), lower inositol phosphates (InsP_2–5) and MYO concentrations in pigs fed diets containing different levels of phytase. Forty pigs were fed 1 of 4 wheat-barley diets on an ad libitum basis for 28 d. The diets comprised a nutritionally adequate positive control (PC), a similar diet but with Ca and P reduced by 1.6 and 1.24 g/kg, respectively (NC), and the NC supplemented with 500 (NC + 500) or 2,000 (NC + 2000) FTU phytase/kg. At the end of the experiment, chyme were collected from the stomach, thoroughly mixed and 2 subsamples (30 mL) were frozen immediately: one snap-frozen at −79 °C and the other at −20 °C. The remaining chyme were left to sit at room temperature (20 °C) and further subsamples were collected and frozen as above at 5, 10 and 15 min from the point of mixing. There were linear reductions in gastric InsP₆ concentration over time during sampling (P < 0.001), irrespective of diet or freezing temperature. Moreover, InsP₆ concentration was influenced by a diet × freezing temperature interaction (P < 0.05), with less InsP₆ measured in chyme frozen at −20 °C than at −79 °C; however, this difference was greater in the control diets than the phytase supplemented diets. Freezing chyme at −79 °C recovered more ∑InsP_2–5 + MYO than freezing at −20 °C in pigs fed phytase supplemented diets; however, this difference was not apparent in the diets without phytase (diet × freezing temperature, P < 0.01). It can be concluded that significant phytate hydrolysis occurs in the gastric chyme of pigs during sampling and processing, irrespective of supplementary phytase activity. Therefore, to minimise post-slaughter phytate degradation and changes in the gastric inositol phosphate profile, chyme should be snap-frozen immediately after collection.