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ABSTRACT: The objective of these studies was to evaluate the impact of dietary muramidase (MUR) on endogenous amino acids (AA) losses and digestibility of nutrients in wheat and corn-based broiler diets. In experiment 1, the effect of dietary MUR on the flow of endogenous AA (EAA) at the jejunum and terminal ileum of broilers were assessed using either the nitrogen (N) free diet method (NFD) or the highly digestible protein diet method (HDP; 100 g casein/kg diet). Sialic acid and muramic acid concentrations were measured in the jejunal content. In experiment 2, a 2x2x2 factorial arrangement of treatments with 2 base grains (wheat or corn), with low or high metabolizable energy (ME) levels, and without or with MUR supplementation was implemented. All diets contained phytase, xylanase, and cellulase. Apparent ileal digestibility (AID) of dry matter (DM), protein (CP), amino acids (AA), crude fat, and energy, as well as the apparent total tract metabolizability (ATTM) of DM, CP, and gross energy (GE) were determined. The standardized ileal digestibility (SID) of AA was obtained by correcting AID values for basal ileal EAA obtained from chicks fed with NFD or HDP in experiment 1, jejunal EAA flow of all AA was higher (P < 0.001) compared to the ileum, but this effect was method dependent. Jejunal, but not ileal, EAA flow measured with HDP was higher compared to NFD, as well as sialic acid (P < 0.001) and muramic acid (P < 0.004) concentrations. Muramidase inclusion had no effect on basal EAA flow, independently of the segment and the method used. In experiment 2, dietary MUR supplementation increased the AID of CP (P < 0.05), all AA, and tended (P = 0.07) to increase the AID of GE, independently of the cereal type used. However, ATTM of DM and GE, but not CP, increased with MUR inclusion compared with the control treatments, especially in wheat and low ME diets (P < 0.05). In conclusion, MUR supplementation improved AID of CP and AA without affecting EAA losses and increases energy utilization.

ABSTRACT: An experiment was conducted to compare the use of a total and digestible Ca formulation system in broilers from hatch to d 37 post-hatch. Ross 308 (n = 288) male broilers were obtained and allocated to one of 2 dietary treatments in floor pens. There were 18 birds per pen and 8 replicate pens per diet. One diet was formulated using ingredient and nutrient recommendations for total Ca and the second diet was formulated using ingredient and nutrient recommendations for standardized ileal digestible (SID) Ca. All diets were formulated to be nutrient adequate using a 2-phase feeding program and including 0.19% available P (avP) and 0.209% total Ca or 0.073% digestible Ca from 1,000 FYT/kg of phytase. On d 17 and 37, tibias and ileal contents were obtained. From hatch to d 37, birds fed diets formulated using digestible Ca gained (P < 0.05) more and were more efficient (P < 0.05) compared with birds fed diets formulated using total Ca. There was no impact of formulation system on tibia ash or minerals. Litter pH (P < 0.05) was greater and litter dry matter (P < 0.05) was lower in birds fed the diets formulated using digestible Ca compared with those fed diets formulated using total Ca. Apparent ileal digestibility (AID) of Ca (P < 0.05), AID of P (P < 0.05) and digestible P intake (P < 0.05) were lower in birds fed diets formulated using digestible Ca compared with those formulated using total Ca at d 17 or 37. However, apparent ileal digested Ca and digestible Ca intake were not different between the experimental diets on d 17 or 37. In conclusion, formulating diets using digestible Ca improved weight gain and feed conversion ratio, but reduced the AID of Ca and P compared with birds fed diets formulated using total Ca. These findings might be reflective of the higher total Ca concentration in the diets formulated using digestible Ca compared with those formulated using total Ca.

ABSTRACT: Three independent trials were conducted to evaluate the efficacy of a novel phytase in laying hens. Trial 1 used a total of 90 laying hens (Lohmann Brown, 33-wk-old) fed either a negative control (NC) diet with 0.09% non-phytate P (NPP) or NC supplemented with 187.5 or 375 FYT phytase/kg feed for 4 d before collection of excreta and ileal digesta to measure ileal digestibility and retention of Ca and P. In trial 2 and 3, a total of 108 laying hens (Hy Line Brown, 25-wk-old) and 360 hens (Lohman Brown, 25-wk-old) were used, respectively. In both trials, the hens were randomly assigned to 3 dietary treatments: NC with 0.1% NPP, positive control (PC) and NC plus 187.5 FYT phytase/kg feed, the experimental diets were fed for 12 wk, and egg production and bone mineralization were measured. The results showed that the ileal digestibility of P increased both linearly (P = 0.012) and quadratically (P = 0.01) with increasing supplementation of phytase in trial 1. In trial 2, phytase supplementation significantly improved egg production, egg weight, and feed conversion ratio and reduced the percentage of broken eggs during the overall trial duration compared with NC. In trial 3, phytase significantly improved egg production, egg weight, and feed intake and reduced the percentage of broken eggs during the entire trial duration. In addition, percentage and weight of bone Ca and P increased significantly with added phytase. In trial 2 and 3, there was no significant difference between PC and the phytase treatment. In conclusion, the novel phytase significantly increased the ileal digestibility of P in a short-term digestibility study and improved egg production and bone mineralization in a 12-wk laying cycle. Ileal digestibility of P rather than P retention in short-term digestibility studies as well as egg production and whole tibia mineralization in long-term studies should be measured to demonstrate the efficacy of phytase in laying hens.

The objective of the present study was to evaluate the effect of a precision biotic (PB; Symphiome®, dsm-firmenich) on the growth performance, nutrient digestibility, litter quality, blood uric acid (UA) concentration, cecal short-chain fatty acids (SCFA) concentration, and ileal and cecal microbiome of broiler chickens fed corn or wheat-based diets. One-day-old broiler chicks were placed in a completely randomized design (2 × 2 factorial scheme) in 4 treatments, 8 replicates/treatment, and 16 birds/replicate. The treatments were a corn or wheat and soybean meal-based diet without or with supplementation of 0.9 kg/MT of PB. All the birds were vaccinated against coccidiosis at the time of placement (Paracox 5). Growth performance was evaluated weekly and at the end of the experiment. At d 35, blood was collected to determine UA concentration and cecal content for SCFA concentration analysis. Ileal digesta was also collected for nutrient digestibility analysis, and ileal digesta and cecal content were collected for microbiome analysis. The data were submitted to two-way ANOVA (P ≤ 0.05), and LSM was used to separate the means in case of interaction. During the starter and grower phases of the study, a better body weight gain (P = 0.0008 and P = 0.04, respectively) was observed in birds fed wheat compared to corn-based diets. From 28 to 36 d of age, the supplementation of PB increased feed intake (P = 0.05), and tended (P = 0.06) to improve the feed conversion ratio by 4.3 points vs non-supplementated birds. Birds fed wheat-based diets had higher (P = 0.02) blood UA than corn based-diets fed birds, and the supplementation of PB led to a reduction (P = 0.02) of blood UA compared to non-supplemented birds. The supplementation of PB changed the abundance of core metabolic pathways of the microbiome, mostly related to protein metabolism, which led to a reduction in blood UA concentration and increase of cecal SCFA concentrations. In conclusion, by beneficially modulating the microbiome, the supplementation of PB was translated into improved growth performance of broiler chickens fed corn or wheat-based diets.