Evaluation of the efficacy of high levels of microbial phytase in broilers

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on April 22, 2009)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Animal sciences.Three experiments were conducted to evaluate the efficacy of high levels of microbial phytase in broiler diets. In experiment one (EXP 1), phytase was included in the diets at 0, 250, 500, 10,000, and 20,000 PU/kg diet. In experiments two and three (EXP 2 and 3), phytase was included in the diets at 0, 500, 2,500, 12,500, and 62,500 PU/kg diet. In all three experiments, dietary Ca and P were reduced to fit industry recommendations. In EXP 1, phytase supplementation improved (P [less than] 0.05) feed intake (FI), body weight gain (BWG), feed:gain (F:G), bone ash (BA), P digestibility (PD), and reduced (P [less than] 0.05) total litter P (TLP) by 53%. In EXP 2, phytase supplementation decreased (P [less than] 0.05) FI, had no effect (P [greater than] 0.05) on BWG, and improved (P [less than] 0.05) F:G, BA, and PD. In EXP 3, phytase supplementation decreased (P [less than] 0.05) FI, improved (P [less than] 0.05) BWG, F:G, BA, PD, and reduced (P [less than] 0.05) TLP by 33%. In young broilers (hatch to 21 days), high levels of dietary phytase improved BWG above the NRC and positive control diets (EXP 1 and 3). However, as broilers reached market weight there were no differences (P [greater than] 0.05) in BWG. Results of this research indicate that microbial phytase was efficacious in broiler diets. However, there were no added benefits to feeding high levels of dietary phytase (in excess of current recommendations) to broilers raised to market weight

Evaluating phosphorus release by phytase in diets fed to growing pigs that are not deficient in phosphorus

Microbial phytase is widely used to enhance digestibility of phytate-P. By tradition, diets with P content well below requirement are used to quantify phytate-P release by phytase, but P-adequate diets may be more physiologically relevant. The objective of this study was to investigate the effects of phytase on P digestion and metabolism and develop a P release curve for phytase in Padequate diets (above requirement according to NRC, 2012), and to compare these effects in a Pdeficient diet. Three replicates of 24 barrows each (BW = 23.0 ± 1.8 kg) were randomly assigned to 1 of 8 dietary treatments, housed in individual pens for 21 d, then moved to metabolism crates for 5 d urine and fecal collections. A basal corn-soybean meal diet (P-adequate, A) was formulated at 0.36% standardized total tract digestible (STTD) P and total Ca:STTD P of 1.83. Phytase was added to A at 200 (A200), 400 (A400), 600 (A600), and 800 (A800) phytase units (FTU)/kg. A positive control diet (PC) was formulated using monocalcium phosphate (MCP) to increase STTD P by 0.16% to 0.52%, the expected STTD P release of 800 FTU/kg. A P-deficient diet (D) was formulated by reducing MCP to achieve 0.21% STTD P, and 200 FTU phytase/kg was added to D for D200. Pig was the experimental unit, and replicate and dietary treatment were fixed effects. Orthogonal polynomial contrasts were used to test linear and quadratic effects of phytase within A, A200, A400, A600, and A800. Phytase increased percent apparent total tract digestibility (ATTD) and STTD of P (quadratic P \u3c 0.001), and quantity of absorbed P (linear P \u3c 0.001; quadratic P = 0.069). Urinary P increased linearly with phytase (P \u3c 0.001) and retained P also increased (linear P = 0.001, quadratic P = 0.094). Phytate-P release was estimated to be 0.049, 0.080, 0.093, and 0.09% STTD P for 200, 400, 600, and 800 FTU/kg, respectively. It appears that the effect of phytase may be lower in P-adequate diets as compared to P-deficient diets, given that there was a 12% improvement for A200 vs A, and a 28% improvement in STTD P for D200 vs D. In conclusion, phytase improved P digestibility and retention in P-adequate diets, and P digestibility was used to estimate the quantity of P released by phytase. Further research investigating P release by phytase in P-adequate diets, rather than Pdeficient diets, may be preferable

Ileal mineral digestibility and expression of nutrient transporter genes of broiler chickens in response to variable dietary total Ca and phytase supplementation are influenced by time on experimental diet and age of the birds

ABSTRACT: Two experiments were conducted to determine the impact of Ca, phytase, sampling time, and age on the digestibility (AID) of Ca and P and the expression of their transporters. Cobb 500 male chicks (N = 600) were used in each experiment and allocated to cages with 10 (Exp 1, 8–11 d) or 5 (Exp 2, 21–24 d) birds/cage and 10 (Exp 1) or 20 (Exp 2) reps/treatment. Treatments were a 2 × 3 factorial arrangement, with low (LOW) or standard (STD) Ca level and 3 phytase (PHY) levels (0, 300, or 3,000 FYT/kg). Ileal digesta were collected at 8, 12, 24, 48, and 72 h, and jejunum tissues at 12, 48, and 72 h after the start of feeding experimental diets. In Exp 1, there was no effect of Ca or phytase on the AID of Ca at 8, 12, or 24 h. Phytase increased the AID of P (P < 0.05) at all time points, and the magnitude was influenced by Ca. At 12 h, the mRNA level of P (NaPi-IIb) and Ca (CaSR) transporters was greatest in the LOW diets without phytase (Ca × PHY, P ≤ 0.06). In Exp 2, the STD diet decreased the AID of Ca and P (P < 0.05) at 8, 24, 48, or 72 h. Phytase increased the AID of Ca (P < 0.05) at 8, 12, and 24 h, and decreased the AID of Ca (quadratic, P < 0.05) in the STD diet (48 h). The AID of P (P < 0.05) increased with phytase at all sampling times. At 48 h, 3,000 FYT/kg decreased (P < 0.05) mRNA expression of NaPi-IIb and Ca transporter ATP2B1 in the STD diet (Ca × PHY, P < 0.05). In conclusion, to avoid adaptation of broilers to Ca and P deficiencies, the optimal time on experimental diets is ≤ 48 h for young broilers and ≤ 24 h in older birds due to up- or down-regulation of Ca and P transporters in response to dietary Ca, P, and phytase

Phosphorus utilization response of pigs and broiler chickens to diets supplemented with antimicrobials and phytase

Three experiments were conducted to evaluate the phosphorus (P) utilization responses of pigs and broiler chickens to dietary supplementation with antimicrobials and phytase and to determine if P digestibility response to phytase is affected by supplementation with antimicrobials. Experiment 1 used 4 diets (a basal negative control formulated to contain 0.41% total P and 0.71% calcium [Ca] without added antimicrobials, basal negative control with added carbadox, basal negative control with added tylosin, or basal negative control with added virginiamycin) and six 18-kg barrows in individual metabolism crates per diet. There was no effect of antimicrobials on P and Ca digestibility or retention. Carbadox supplementation increased (P < 0.05) digestibility and retention of gross energy (GE) and supplementation with tylosin increased (P < 0.05) N retention relative to the basal negative control diet. Experiment 2 used eight 19-kg barrows in individual metabolism crates per treatment and 9 dietary treatments arranged in a 3 × 3 factorial of antimicrobials (none, tylosin, or virginiamycin) and phytase (0, 500, or 1,500 FTU/kg). Phytase addition to the diets linearly increased (P < 0.05) apparent total tract digestibility or retention of P, Ca, nitrogen (N) and GE. Supplementation with antimicrobials did not affect apparent total tract digestibility or retention of P, Ca, N or GE. There were linear effects (P < 0.01) of phytase on Ca utilization in diets that were not supplemented with antimicrobials but only tendencies (P < 0.10) in diets supplemented with tylosin or virginiamycin. Phytase linearly improved (P < 0.05) N utilization in diets supplemented with tylosin or virginiamycin but not in diets without added antimicrobials. Experiment 3 was a broiler chicken experiment with the same experimental design as Exp. 2 but feeding 8 birds per cage and 10 replicate cages per diet. Antimicrobial supplementation improved (P < 0.05) feed efficiency and adding tylosin improved (P < 0.05) tibia ash but did not affect nutrient utilization. Dietary phytase improved (P < 0.01) growth performance, tibia ash and apparent ileal digestibility and retention of P regardless of antimicrobial supplementation. Overall, phytase supplementation improved growth performance and nutrient digestibility and retention, regardless of supplementation of diets with antimicrobials. Supplementation of diets with antimicrobials did not affect P digestibility or retention because of a lack of interaction between antimicrobials and phytase, there was no evidence that P digestibility response to phytase is affected by supplementation with antimicrobials

Dietary Oxidative Distress: A Review of Nutritional Challenges as Models for Poultry, Swine and Fish

The redox system is essential for maintaining cellular homeostasis. When redox homeostasis is disrupted through an increase of reactive oxygen species or a decrease of antioxidants, oxidative distress occurs resulting in multiple tissue and systemic responses and damage. Poultry, swine and fish, raised in commercial conditions, are exposed to different stressors that can affect their productivity. Some dietary stressors can generate oxidative distress and alter the health status and subsequent productive performance of commercial farm animals. For several years, researchers used different dietary stressors to describe the multiple and detrimental effects of oxidative distress in animals. Some of these dietary challenge models, including oxidized fats and oils, exposure to excess heavy metals, soybean meal, protein or amino acids, and feeding diets contaminated with mycotoxins are discussed in this review. A better understanding of the oxidative distress mechanisms associated with dietary stressors allows for improved understanding and evaluation of feed additives as mitigators of oxidative distress

Quantifying the effect of coccidiosis on broiler performance and infection outcomes in the presence and absence of control methods

A systematic review and meta-analysis was conducted to investigate the role of Eimeria species, dose and inoculation time, on performance and infection outcomes of different broiler strains infected for different study durations. The meta-analysis addressed E. acervulina, E. maxima, E. tenella, and mixed species infections, and involved data from 72 peer-reviewed articles, corresponding to 521 treatments performed on 20,756 broilers. A secondary objective was to investigate the effects of synthetic anticoccidials, ionophores, and vaccination against Eimeria on the above outcomes. Performance during infection was scaled (%) to that of the uninfected birds. Infection reduced scaled ADFI and ADG (P < 0.001) and increased feed conversion ratio (FCR; P < 0.05); there was a significant interaction between dose and species on scaled ADFI and ADG, suggesting that different species affected these variables to different extents (P < 0.001). There was a tendency for an interaction between dose and broiler strain on scaled ADFI (P = 0.079), and a significant interaction between these variables on scaled ADG (P < 0.01). A tendency for an interaction between oocyst dose and Eimeria species (P = 0.067) on maximum number of oocysts excreted was observed. Lesion scores were significantly affected by dose, species, and their interaction (P < 0.05), the latter caused by an increase in the lesion scores during E. maxima and E. tenella infections. Control methods significantly affected scaled ADG and FCR (P < 0.05) and there was an interaction between dose and control methods on ADFI (P < 0.001). Synthetic anticoccidial use improved scaled ADG (P < 0.01), whereas ionophores improved FCR compared with untreated birds (P < 0.01). An interaction between dose and control method on scaled ADFI was caused by the higher ADFI of vaccinated compared to untreated birds, as dose increased. There was a significant effect of control methods on lesion scores (P < 0.01). All findings advance our understanding of the factors that influence the impact of coccidiosis and its controls in broilers

Evaluating phosphorus release by phytase in diets fed to growing pigs that are not deficient in phosphorus

Microbial phytase is widely used to enhance digestibility of phytate-P. By tradition, diets with P content well below requirement are used to quantify phytate-P release by phytase, but P-adequate diets may be more physiologically relevant. The objective of this study was to investigate the effects of phytase on P digestion and metabolism and develop a P release curve for phytase in Padequate diets (above requirement according to NRC, 2012), and to compare these effects in a Pdeficient diet. Three replicates of 24 barrows each (BW = 23.0 ± 1.8 kg) were randomly assigned to 1 of 8 dietary treatments, housed in individual pens for 21 d, then moved to metabolism crates for 5 d urine and fecal collections. A basal corn-soybean meal diet (P-adequate, A) was formulated at 0.36% standardized total tract digestible (STTD) P and total Ca:STTD P of 1.83. Phytase was added to A at 200 (A200), 400 (A400), 600 (A600), and 800 (A800) phytase units (FTU)/kg. A positive control diet (PC) was formulated using monocalcium phosphate (MCP) to increase STTD P by 0.16% to 0.52%, the expected STTD P release of 800 FTU/kg. A P-deficient diet (D) was formulated by reducing MCP to achieve 0.21% STTD P, and 200 FTU phytase/kg was added to D for D200. Pig was the experimental unit, and replicate and dietary treatment were fixed effects. Orthogonal polynomial contrasts were used to test linear and quadratic effects of phytase within A, A200, A400, A600, and A800. Phytase increased percent apparent total tract digestibility (ATTD) and STTD of P (quadratic P This is a manuscript of an article published as Olsen, Kristin M., Stacie A. Gould, Carrie L. Walk, Nick VL Serão, Stephanie L. Hansen, and John F. Patience. "Evaluating phosphorus release by phytase in diets fed to growing pigs that are not deficient in phosphorus." Journal of animal science 97, no. 1 (2019): 327-337. doi:10.1093/jas/sky402. Posted with permission.</p

The Growth Performance, Nutrient Digestibility, Gut Bacteria and Bone Strength of Broilers Offered Alternative, Sustainable Diets Varying in Nutrient Specification and Phytase Dose

This study assessed the use of locally sourced sustainable feed ingredients, rapeseed meal (RSM) and maize dried distiller grains with solubles (DDGS) in diets over traditional ingredients on the growth performance, bone strength and nutrient digestibility of broilers. This work also investigated the effects of supplementing exogenous phytase in two doses (500 vs. 1500 FTU/kg). Using male Ross 308 chicks (n = 320) assigned to receive one of four experimental diets: (1) Positive control diet 1 (PC1), a wheat, soya-based diet + 500 FTU/kg phytase. (2) Positive control diet 2, RSM/DDGS diet + 500 FTU/kg phytase (PC2). (3) Negative control (NC) reduced nutrient RSM/DDGS diet, no phytase. (4) The NC diet plus 1500 FTU/kg phytase (NC+). PC1 birds displayed higher feed intake and body weight gain consistently throughout the trial (p &lt; 0.001) as well as increased body weight by 28 d and 42 d (p &lt; 0.001). Whole-body dual emission X-ray absorptiometry (DXA) analysis revealed PC1 birds also had higher bone mineral density (BMD), bone mineral content (BMC), total bone mass, total lean mass and total fat mass than birds offered other treatments (p &lt; 0.01). Diet had no significant effect on bone strength. Phytase superdosing improved the digestibility of dry matter (DM), neutral detergent fibre (NDF), gross energy (GE), calcium (Ca), potassium (K) and magnesium (Mg) compared to birds in other treatment groups. The phytase superdose also improved performance in comparison to birds offered the NC diet. Phytase superdosing increased the IP6 and IP5 degradation and increased the ileal inositol concentration of the birds. N excretion was lower for birds offered the traditional wheat&ndash;soya diet and highest for those offered the high-specification RSM/DDGS diet with a commercial dose of phytase. The addition of a phytase superdose to the negative control diet (NC+) reduced P excretion of birds by 15% compared to birds offered NC