Novel 4th-generation phytase improves broiler growth performance and reduces woody breast severity through modulation of muscle glucose uptake and metabolism.

The objective of the present study was to determine the effect of a novel (4th generation) phytase supplementation as well as its mode of action on growth, meat quality, and incidence of muscle myopathies. One-day old male broilers (n = 720) were weighed and randomly allocated to 30 floor pens (24 birds/pen) with 10 replicate pens per treatment. Three diets were fed from hatch to 56- days-old: a 3-phase corn-soy based diet as a positive control (PC); a negative control (NC) formulated to be isocaloric and isonitrogenous to the PC and with a reduction in Ca and available P, respectively; and the NC supplemented with 2,000 phytase units per kg of diet (NC + P). At the conclusion of the experiment, birds fed with NC + P diet were significantly heavier and had 2.1- and 4.2-points better feed conversion ratio (FCR) compared to birds offered NC and PC diets, respectively. Processing data showed that phytase supplementation increased live weight, hot carcass without giblets, wings, tender, and skin-on drum and thigh compared to both NC and PC diets. Macroscopic scoring showed that birds fed the NC + P diet had lower woody breast (WB) severity compared to those fed the PC and NC diets, however there was no effect on white striping (WS) incidence and meat quality parameters (pH, drip loss, meat color). To delineate its mode of action, iSTAT showed that blood glucose concentrations were significantly lower in birds fed NC + P diet compared to those offered PC and NC diets, suggesting a better glucose uptake. In support, molecular analyses demonstrated that the breast muscle expression (mRNA and protein) of glucose transporter 1 (GLUT1) and glucokinase (GK) was significantly upregulated in birds fed NC + P diet compared to those fed the NC and PC diets. The expression of mitochondrial ATP synthase F0 subunit 8 (MT-ATP8) was significantly upregulated in NC + P compared to other groups, indicating intracellular ATP abundance for anabolic pathways. This was confirmed by the reduced level of phosphorylated-AMP-activated protein kinase (AMPKα1/2) at Thr172 site, upregulation of glycogen synthase (GYS1) gene and activation of mechanistic target of rapamycin and ribosomal protein S6 kinase (mTOR-P70S6K) pathway. In conclusion, this is the first report showing that in-feed supplementation of the novel phytase improves growth performance and reduces WB severity in broilers potentially through enhancement of glucose uptake, glycolysis, and intracellular ATP production, which used for muscle glycogenesis and protein synthesis.

Growth performance, organ attributes, nutrient and caloric utilization in broiler chickens differing in growth rates when fed a corn-soybean meal diet with multienzyme supplement containing phytase, protease and fiber degrading enzymes.

Growth performance, organ weight, ceca digesta short chain fatty acids (SCFA), jejunal histomorphometry, tibia ash, apparent retention (AR) of components and caloric efficiency were investigated in broiler chicken strains differing in growth rate fed diets with multienzyme supplement (MES). The strains differed in estimated time to reach 2.1 kg BW: 37, 43, 47, and 50 d and were designated C, F, J, and N, respectively. A corn-soybean meal diet was formulated for 2-phase program (starter and grower) and fed without or with MES containing phytase, protease and fiber-degrading enzymes. A total of 640-day-old chicks (42.3 + 0.01 g/bird) were housed in cages (5 cockerels and 5 pullets/cage) and allocated to give 8 replicates/ strain and diet combination. Equal amount of feed was fed based on observed ad-libitum intake of C strain in the starter (d 0-14) and grower (d 15-28). Body weight was monitored, grab excreta samples taken and at completion of allocated feed one bird per cage necropsied for samples. With exception of P, apparent metabolizable energy corrected for nitrogen (AMEn) and ceca digesta acetic acid, there was no (P > 0.05) interaction between strain and MES on examined responses. Strains differed (P < 0.01) on growth, FCR, gizzard weight, tibia ash, breast weight, ceca digesta concentration of lactic, propionic, and isobutyric acid and caloric efficiency. The final body weight (BW) was 1,344, 1,134, 959, and 916 g/bird for C, F, J, and N, respectively. Corresponding caloric efficiency was 4,930, 5,807, 6,680 and 7,199 kcal/kg BW gain, respectively. Birds fed MES had higher BW gain (P < 0.05) in grower phase, larger gizzard, higher AR of CP, crude fat, neutral detergent fiber, and Ca than non-MES birds. In conclusion, growth rate influenced organ attributes, nutrient, and caloric utilization. Enzyme supplementation improved growth in grower phase and nutrient utilization independent of strain, suggesting that effects of feed enzymes are not influenced by inherent growth rate.

Debranching enzymes in corn/soybean meal-based poultry feeds: a review.

This review discusses the complex nature of the primary nonstarch polysaccharide (NSP) in corn with respect to the merit of debranching enzymes. Celluloses, hemicelluloses, and pectins comprise the 3 major categories of NSP that make up nearly 90% of plant cell walls. Across cereals, the hemicellulose arabinoxylan exists as the primary NSP, followed by cellulose, glucans, and others. Differences in arabinoxylan structure among cereals and cereal fractions are facilitated by cereal type, degree and pattern of substitution along the xylan backbone, phenol content, and cross-linkages. In particular, arabinoxylan (also called glucuronoarabinoxylan) in corn is heavily fortified with substituents, being more populated than in wheat and other cereal grains. Feed-grade xylanases - almost solely of the glycoside hydrolase (GH) 10 and GH 11 families - require at least 2 or 3 contiguous xylose units to be free of attachments to effectively attack the xylan chain. This canopy of attachments, along with a high phenol content and the insoluble nature of corn glucuronoarabinoxylan, confers a significant resistance to xylanase attack. Both in vitro and in vivo studies demonstrate that debranching enzymes appreciably increase xylanase access and fiber degradability by removing these attachments and breaking phenolic linkages. The enzymatic degradation of the highly branched arabinoxylan can facilitate disassembly of other fibers by increasing exposure to pertinent carbohydrases. For cereals, the arabinofuranosidases, α-glucuronidases, and esterases are some of the more germane debranching enzymes. Enzyme composites beyond the simple core mixes of xylanases, cellulases, and glucanases can exploit synergistic benefits generated by this class of enzymes. A broad scope of enzymatic activity in customized mixes can more effectively target the resilient NSP construct of cereal grains in commercial poultry diets, particularly those in corn-based feeds.

Digestibility of amino acids, energy, and minerals in roasted full-fat soybean and expelled-extruded soybean meal fed to growing pigs without or with multienzyme supplement containing fiber-degrading enzymes, protease, and phytase.

Indigestible fiber-protein-phytate complexes reduce the feeding value of soy products. We investigated the effects of multienzyme supplement (MES, Victus) on standardized ileal digestibility (SID) of amino acids (AA) and apparent total tract digestibility (ATTD) of energy and minerals in roasted full-fat soybean (FFSB) seeds and expelled-extruded soybean meal (SBM) fed to growing pigs. The crude protein (CP) was 33.4% and 42.8% dry matter (DM) in FFSB seeds and SBM, respectively and corresponding values for crude fat were 17.4% and 11.8% DM. Semi-purified diets with 50% of either FFSB seeds or SBM as the sole source of AA were prepared without or with MES supplying phytase, protease, xylanase, and ß-glucanase at 2,200, 8,300, 400, and 100 U/kg of feed, respectively. Diets had TiO2 as an indigestible marker and the ratio of cornstarch to sucrose and corn oil was identical to calculate DE by the difference method. Eight ileal-cannulated barrows (22.1 ± 0.61 kg) were fed diets in a replicated 4 × 4 Latin square design to give eight replicates per diet. The period lasted for 9 d: 5 d for acclimation, 2 d for fecal, and 2 d for ileal digesta samples. There was no (P > 0.05) interaction between soy type and MES or MES effect on SID of AA; SBM had higher (P < 0.05) SID of CP, His, Leu, and Lys. There was no (P > 0.05) interaction between soy type and MES on energy digestibility. The FFSB seeds had higher ATTD of gross energy (GE, 80.2% vs. 76.6%; P < 0.01) than SBM. Pigs fed MES had higher (P < 0.05) ATTD of DM (91.3% vs. 87.7 %), GE (87.5% vs. 82.4%), CP (86.4% vs. 82.9%), crude fat (70.6% vs. 54.9%), Ca (63.2% vs. 60.2%), and P (67.5% vs. 63.2%). In conclusions, differences on AA and energy digestibility in soy products could be linked to processing and compositional differences. Although MES had no effect on SID of AA, the effects on the utilization of minerals and energy demonstrated the value of fiber-degrading enzymes, protease, and phytase in improving the nutritive value of soy products independent of processing.