The interactions of exogenous phytase with whole grain feeding and effects of barley as the whole grain component in broiler diets based on wheat, sorghum and wheat-sorghum blends

The objectives of this experiment were two-fold; the first was to evaluate exogenous phytase in either conventional or whole grain diets as a 2 × 2 factorial treatment array. Wheat-sorghum blended rations containing 12.5% ground or whole barley were offered without and with 1000 FTU/kg exogenous phytase. The second objective was to evaluate barley as the whole grain component in diets based on wheat, sorghum and equal wheat-sorghum blends as a 3 × 2 factorial treatment array. Rations based on wheat, sorghum and wheat-sorghum blends were offered as an intact pellet containing 12.5% ground barley or offered as a mix of 12.5% whole barley and a pelleted concentrate. Each of the dietary treatments was offered to 7 replicates (6 birds per cage) of male Ross 308 chicks from 7 to 28 days post-hatch. Treatment effects on growth performance, gizzard and pancreas weights, gizzard pH, bone mineralisation, nutrient utilisation, digestibility coefficients of starch and protein (N) and starch:protein disappearance rate ratios in four small intestinal segments (proximal and distal jejunum, proximal and distal ileum), excreta dry matter and incidence of dilated proventriculi were determined. In the 2 × 2 analysis there was a significant (

The handbook for standardized field and laboratory measurements in terrestrial climate change experiments and observational studies (ClimEx)

1. Climate change is a world‐wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil–plant–atmosphere continuum. An increasing number of climate change studies are creating new opportunities for meaningful and high‐quality generalizations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis and upscaling. Many of these challenges relate to a lack of an established ‘best practice’ for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change. 2. To overcome these challenges, we collected best‐practice methods emerging from major ecological research networks and experiments, as synthesized by 115 experts from across a wide range of scientific disciplines. Our handbook contains guidance on the selection of response variables for different purposes, protocols for standardized measurements of 66 such response variables and advice on data management. Specifically, we recommend a minimum subset of variables that should be collected in all climate change studies to allow data re‐use and synthesis, and give guidance on additional variables critical for different types of synthesis and upscaling. The goal of this community effort is to facilitate awareness of the importance and broader application of standardized methods to promote data re‐use, availability, compatibility and transparency. We envision improved research practices that will increase returns on investments in individual research projects, facilitate second‐order research outputs and create opportunities for collaboration across scientific communities. Ultimately, this should significantly improve the quality and impact of the science, which is required to fulfil society's needs in a changing world

Fishmeal and maize starch inclusions in sorghum-soybean meal diets generate different responses in growth performance, nutrient utilisation, starch and protein digestive dynamics of broiler chickens

This study comprised a 2 × 2 factorial array of dietary treatments offered to male Ross 308 broiler chicks from 15 to 28 days post-hatch. The dietary treatments consisted of a sorghum-soybean meal diet in which either sorghum was partially substituted by maize starch (200 g/kg) or soybean meal was partially substituted by fishmeal (175 g/kg). Growth performance, nutrient utilisation, digesta retention times in four small intestinal segments, starch and protein (N) digestibility coefficients and disappearance rates (g/bird/day) and starch:protein disappearance rate ratios in four small intestinal segments were determined. The partial substitution of soybean meal by fishmeal had the more profound effects on the parameters assessed as fishmeal inclusions improved weight gain by 12.1% (1260 versus 1124 g/bird,

Dietary starch influences growth performance, nutrient utilisation and digestive dynamics of protein and amino acids in broiler chickens offered low-protein diets

A total of 288 day-old, male Ross 308 chicks were offered six dietary treatments from 7 to 28 days post-hatch. A standard maize-soy diet was compared with five low protein diets containing high inclusions of maize starch and various combinations of supplemental amino acids. The assessed parameters included growth performance, nutrient utilisation, digestibility coefficients and disappearance rates of starch, protein and amino acids in four small intestinal segments. Also, the effects of three dietary treatments on free plasma amino acid concentrations in the anterior mesenteric vein or portal circulation were determined. The transition from standard to low protein diets elevated feed intakes and compromised FCR. Overall, tangible differences in responses were not observed in birds offered the five low protein diets which effectively precluded meaningful comparisons between the various combinations of crystalline amino acids. Maize starch inclusions in low protein diets enhanced starch digestibility coefficients and disappearance rates and parameters of nutrient utilisation. However, maize starch also depressed protein digestibility coefficients and disappearance rates. Moreover, amino acid digestibility coefficients were depressed in the three posterior segments of the small intestine. Instructively, proximal ileal starch digestibility coefficients were negatively correlated with digestibility coefficients of twelve amino acids in the proximal ileum to significant extents. Significant differences in concentrations of free amino acids in plasma from the anterior mesenteric vein were observed for histidine, lysine, methionine, threonine and valine in birds offered the standard and two low protein diets. The possibility that glucose and amino acids were effectively competing for intestinal uptakes, especially from the ileum, is discussed. Also, it appears that the metabolic fates of amino acids in enterocytes of the gut mucosa can be manipulated by dietary strategies and that crystalline amino acids may be less prone to undergo catabolism in the gut mucosa