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Romsey, Australia

Liu S.Y.,University of Sydney | Cadogan D.J.,Feedworks | Peron A.,DuPont Company | Truong H.H.,DuPont Company | Selle P.H.,DuPont Company
Animal Production Science

In order to examine the influence of an enzyme combination of xylanase, amylase and protease on growth performance and energy utilisation in boiler chickens offered maize-, sorghum- and wheat-based diets and also determine the impact of exogenous enzymes on digestive dynamics of starch and protein in the small intestine and their relativity to broiler performance, a 3 × 2 factorial array of dietary treatments were offered to 288 male Ross 308 chicks from 7 to 27 days post-hatch. Apparent digestibility coefficients of starch, protein and fat in the proximal jejunum, distal jejunum, proximal ileum and distal ileum were determined at Day 27. The digestion rates of starch, protein and energy were predicted by using exponential mathematical models to fit apparent digestibility coefficients with mean retention times in each small intestinal segment. Sorghum-based diets supported the highest weight gain (P < 0.05) and feed intake (P < 0.05) but feed conversion ratios (FCR) were similar across all three grain-based diets (P > 0.10). There were significant interactions between grain type and enzyme supplementation in FCR and the enzyme combination significantly improved FCR in maize-based diets only (P < 0.01). The enzyme combination significantly increased apparent metabolisable energy (AME) in all three grain-based diets (P < 0.05) and increased nitrogen-corrected apparent metabolisable energy (AMEn) in maize- and wheat-based diets (P < 0.05). Wheat-based diets had the lowest N retention (P < 0.01), relative gizzard weight (P < 0.001) and highest gizzard pH (P < 0.05). There were significant grain × enzyme supplementation interactions for starch (P < 0.01) and N (P < 0.05) digestibility coefficients in the four small intestinal segments. Starch digestibility responses to the enzyme combination were most pronounced in wheat-based diets with significant improvement in all segments. The enzyme combination significantly retarded starch digestion rates (P < 0.05) but did not influence protein (N) digestion rates (P > 0.25). In conclusion, feed conversion of sorghum-based diet (1.475) was significantly more efficient than those based on maize (1.518) and wheat (1.532) in non-supplemented diets. The enzyme combination significantly improved energy utilisation (AME) in all three grain-based diets and improved feed conversion efficiency in maize-based diets. © 2015 CSIRO. Source

Liu S.Y.,University of Sydney | Cadogan D.J.,Feedworks | Peron A.,DuPont Company | Truong H.H.,University of Sydney | Selle P.H.,University of Sydney
Animal Feed Science and Technology

To investigate the effects of phytase supplementation on growth performance, nutrient utilization and digestive dynamics of starch and protein, a study was conducted using 288 male Ross 308 chicks (6 treatments with 8 replicate cages of 6 birds). Birds were offered steam-pelleted diets based on maize, sorghum or wheat, without or with phytase supplementation, from 7 to 27 days post-hatch. Experimental diets were formulated to be equivalent for energy, protein/amino acids and were P-adequate. Digesta samples from proximal jejunum, distal jejunum, proximal ileum and distal ileum were collected in their entirety at day 27. Digestion rates of starch and protein were determined by fitting exponential mathematical model to apparent digestibility coefficients with mean retention times in each small intestinal segment. The growth performance of birds offered maize and sorghum were comparable but those offered wheat-based diets were inferior. Phytase improved weight gain (P<0.001), feed intake (P<0.001) and feed conversion (P<0.05) in maize-, sorghum- and wheat- based diets, although the most pronounced improvements tended to be for maize. There were grain type-phytase interactions (P<0.01) for nutrient utilization (AME, N retention, AMEn) where substantial phytase responses were observed for maize but not for sorghum- and wheat-based diets. Phytase did not influence digestion rates of starch and protein (P>0.05), but it significantly increased disappearance rates of starch in maize-based diets (P<0.05). In conclusion, phytase improved weight gain and feed conversion efficiency in maize-, sorghum- and wheat-based diets with more pronounced response in maize-based diets. Moreover, phytase also significantly enhanced nutrient utilization in maize-based diets. © 2014 Elsevier B.V. Source

Selle P.H.,University of Sydney | Cadogan D.J.,Feedworks | Li X.,University of Queensland | Bryden W.L.,University of Queensland
Animal Feed Science and Technology

Sorghum-based diets have been associated with inconsistent, and even sub-optimal, growth performance of broiler chickens. Sorghum is unique in that it contains kafirin, phytate and may contain condensed tannin; these factors can negatively influence the nutritive properties of sorghum. Both phytate and tannin have the capacity to complex proteins in the gut and depress protein digestibility and intestinal uptakes of dietary and endogenous amino acids (AA). A substantial proportion of sorghum protein is composed of kafirin, which is relatively poorly digested and contains a paucity of lysine (lys). Therefore, as kafirin proportions of sorghum protein increase, digestibility of AA and lys concentrations decline. Because of variable AA concentrations in sorghum protein, the accuracy with which intended dietary levels of AA are met in formulating sorghum-based diets may not be precise. Kafirin is also associated with harder grain textures and higher starch gelatinisation temperatures and the digestibility of starch in sorghum is generally inferior to other grains. The particle size and method of grinding sorghum influences broiler performance but the optimal particle size appears to be dependent on grain texture. Sorghum is vulnerable to 'moist-heat' because it induces disulphide cross-linkages in β- and γ-kafirin located in the periphery of protein bodies that represents a barrier to the more digestible, centrally located α-kafirin component. Starch granules are intimately associated with protein bodies and the protein matrix in sorghum endosperm and starch digestibility is also compromised by the formation of disulphide cross-linkages, which impede starch gelatinisation and enzymic degradation. This raises the possibility that steam-pelleting sorghum-based diets at high temperatures may constitute sufficient 'moist-heat' to compromise nutrient utilisation. The identification of the most appropriate processing methods of sorghum-based diets should prove advantageous and inclusion of exogenous proteases with the capacity to degrade kafirin may hold promise. In low-tannin, phytase-supplemented, sorghum-based diets the more important causes of inconsistent broiler performance may be the kafirin content, variable concentrations and digestibilities of AA and grain texture coupled with inappropriate processing methods. © 2010 Elsevier B.V. All rights reserved. Source

Selle P.H.,University of Sydney | Cadogan D.J.,Feedworks | Ru Y.J.,Danisco | Partridge G.G.,Danisco
International Journal of Poultry Science

The impact of two enzyme preparations in either sorghum- or wheat-based broiler diets on nutrient utilization and growth performance was determined. One preparation (Enzyme A) combined protease, xylanase and β-glucanase activities and the second (Enzyme P) contained xylanase activity. Sorghum- or wheat-based starter (1-14 days), grower (15-28) and finisher (29-42) diets without or with either Enzyme A or Enzyme P were offered to broilers from 1-42 days post-hatch. Each of the six dietary treatments was offered to six replicates of six birds per cage. Total excreta collections were completed in the grower and finisher phases to determine the effects of dietary treatments on nutrient utilization as assessed by Apparent Metabolizable Energy (AME), Nitrogen (N) retention and N-corrected AME (AMEn). Both preparations contained similar levels of xylanase activity and enhanced nutrient utilization in wheat-based broiler diets with more pronounced responses in the finisher phase. In this phase, Enzyme A significantly increased AME by 0.98 MJ, N retention by 4.80 percentage units and AMEn by 0.95 MJ/kg. Similarly, Enzyme P increased AME by 1.21 MJ, N retention by 4.25 percentage units and AMEn by 1.24 MJ/kg. In contrast, enzyme inclusions in sorghum-based grower and finisher diets did not influence nutrient utilization and this is reflected in significant treatment interactions (p<0.001) for AME and AMEn in the finisher phase. In broilers offered wheat-based diets, both enzymes similarly improved growth performance; Enzyme A and Enzyme P significantly improved feed efficiency by 7.0% and 7.1%, respectively, from 1-42 days post-hatch. In sorghum-based diets, Enzyme P numerically depressed feed efficiency; whereas Enzyme A marginally enhanced feed efficiency and increased weight gain by 6.7%, which closely approached significance (p<0.06). Kafirin is the dominant protein fraction in sorghum and the possibility that the protease component in Enzyme A, subtilisin, has the capacity to degrade kafirin is considered.© Asian Network for Scientific Information, 2010. Source

Truong H.H.,University of Sydney | Truong H.H.,University of New England of Australia | Yu S.,DuPont Company | Peron A.,DuPont Company | And 5 more authors.
Animal Feed Science and Technology

The effects of phytase supplementation on growth performance, nutrient utilisation, starch and protein digestive dynamics in broiler chickens offered maize-, sorghum- and wheat-based diets were determined in a previous study (Liu et al., 2014). Responses to phytase were most pronounced in maize-based diets, which suggest that more phytate was degraded in these diets. Relevant retained samples of grain, diets and digesta from four small intestinal segments were retrospectively analysed for concentrations of phytate, sodium and starch pasting properties to investigate the hypothesis that phytate in maize-based diets was more completely degraded by exogenous phytase. Exogenous phytase significantly (P<0.001) degraded dietary phytate in the proximal jejunum, distal jejunum, proximal ileum and distal ileum and increased distal ileal phytate digestibility coefficients from 0.238 to 0.631. There were significant differences (P<0.001) between diets based on maize (0.515), wheat (0.449) and sorghum (0.340) for distal ileal phytate digestibility coefficients. Phytase accelerated phytate disappearance rates from all four segments and increased distal ileal phytate disappearance rates from 201 to 535. mg/bird/day. This was significantly more pronounced in maize (459. mg/bird/day) than in diets based on sorghum (301. mg/bird/day) and wheat (343. mg/bird/day). Sodium digestibility coefficients were significantly improved (P<0.01) by exogenous phytase in proximal jejunum, distal jejunum and proximal ileum. Exogenous phytase significantly influenced starch properties of experimental diets determined by rapid visco-analysis (RVA). There were significant negative correlations between RVA setback viscosity of starch in experimental diets and starch digestibility coefficients at the distal jejunum (r = -0.438; P<0.01) and proximal ileum (r = -0.591; P<0.001) determined in the Liu et al. (2014) study. Distal ileal phytate digestibility coefficients appeared to be higher in non-supplemented, maize-based diets (0.349) than in diets based sorghum (0.128) and wheat (0.239) thus the likelihood is that phytate in maize-based diets was more readily degraded by endogenous, mucosal phytase in the small intestine. Consideration is given to the possibilities that location of phytate within grains influences phytate degradation and that the relatively low sodium concentrations in maize-based diets may have contributed to the more robust responses to exogenous phytase observed. © 2014. Source

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