Genotypes of cereal grains, including winter barley (n = 21), maize (n = 27), oats (n = 14), winter rye (n = 22), winter triticale (n = 21) and winter wheat (n = 29), were assayed for their chemical composition and physical characteristics as part of the collaborative research project referred to as GrainUp. Genotypes of one grain species were grown on the same site, except maize. In general, concentrations of proximate nutrients were not largely different from feed tables. The coefficient of variation (CV) for the ether extract concentration of maize was high because the data pool comprised speciality maize bred for its high oil content. A subset of 8 barley, 20 rye, 20 triticale and 20 wheat samples was analysed to differ significantly in several carbohydrate fractions. Gross energy concentration of cereal grains could be predicted from proximate nutrient concentration with good accuracy. The mean lysine concentration of protein was the highest in oats (4.2 g/16 g N) and the lowest in wheat (2.7 g/16 g N). Significant differences were also detected in the concentrations of macro elements as well as iron, manganese, zinc and copper. Concentrations of arsenic, cadmium and lead were below the limit of detection. The concentration of lower inositol phosphates was low, but some inositol pentaphosphates were detected in all grains. In barley, relatively high inositol tetraphosphate concentration also was found. Intrinsic phytase activity was the highest in rye, followed by triticale, wheat, barley and maize, and it was not detectable in oats. Substantial differences were seen in the thousand seed weight, test weight, falling number and extract viscoelasticity characteristics. The study is a comprehensive overview of the composition of different cereal grain genotypes when grown on the same location. The relevance of the variation in composition for digestibility in different animal species will be subject of other communications.

We studied the effects of increasing dietary concentrations of each of the following amino acids on growth, feed intake, feed conversion ratio and composition of gain in rainbow trout in six dose-response experiments: L-lysine, L-tryptophan, L -histidine, L-valine, L-leucine and L-isoleucine. Semipurified diets containing 20.1 MJ digestible energy/kg dry matter, with wheat gluten and crystalline amino acids as sole sources of amino acids, were fed to rainbow trout [initial mean body weight (BW) 40–51 g, depending on the amino acid studied]. In one series of 24 diets, lysine concentration ranged from 4.5 to 58.0 g/kg dry matter; in five further series of 12 diets each, concentrations ranged from (in g/kg dry matter): tryptophan, 1.3 to 5.6; histidine, 2.6 to 13.5; valine, 6.2 to 34.2; leucine, 10.0 to 42.0 and isoleucine, 5.0 to 15.3. Each diet was fed to a group of 20 fish for 53–64 d, depending on the amino acid studied. Dry matter intake, weight gain, feed conversion ratio, protein concentration of gain and total protein deposition followed exponential response functions. To achieve 95% of the maximum protein deposition, dietary concentrations of 27.7 g lysine, 2.0 g tryptophan, 5.8 g histidine, 15.7 g valine, 13.6 g leucine and 13.7 g isoleucine/kg dry matter were required. Maintenance requirements, estimated from exponential functions for protein deposition, were [in mg/(100 g BW⋅d)]: lysine, 1.93; tryptophan, 1.05; histidine, 1.07; valine, 2.92; leucine, 8.26 and isoleucine, 0.91. This corresponds to 4% of the requirement for protein deposition for lysine and isoleucine but 32% for leucine, with the other amino acids being intermediate. Therefore, different dietary amino acid requirement patterns were derived from protein deposition data depending on the chosen level of performance.

The objective was to characterise degradation ofmyo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP₆) and formation of inositol phosphate (InsP) isomers in different segments of the broiler digestive tract. Influence of anAspergillus niger(PhyA) and twoEscherichia coli-derived (PhyE1 and PhyE2) phytases was also investigated. A total of 600 16-d-old broilers were allocated to forty floor pens (ten pens per treatment). Low-P (5·2 g/kg DM) maize–soyabean meal-based diets were fed without (basal diet; BD) or with a phytase added. On day 25, digesta from different digestive tract segments were pooled per segment on a pen-basis, freeze-dried and analysed for P, InsP isomers and the marker TiO₂. InsP₆degradation until the lower ileum (74 %) in BD-fed birds showed a high potential of broilers and their gut microbiota to hydrolyse InsP₆in low-P diets. Different InsP patterns in different gut segments suggested the involvement of phosphatases of different origin. Supplemented phytases increased InsP₆hydrolysis in the crop (P < 0·01) but not in the lower ileum. Measurements in the crop and proventriculus/gizzard confirmed publishedin vitrodegradation pathways of 3- and 6-phytases for the first time. In the intestinal segments, specifically formed InsP_4–5isomers of supplemented phytases were still present, indicating further activity of these enzymes.Myo-inositol tetrakisphosphate (InsP₄) accumulation differed between PhyE1 and PhyE2 compared with PhyA in the anterior segments of the gut (P < 0·01). Thus, the hydrolytic cleavage of the first phosphate group is not the only limiting step in phytate degradation in broilers.

Effects of increasing dietary concentrations of phosphorus on growth, feed intake, feed conversion, composition of gain and concentration of inorganic phosphate in plasma were studied in rainbow trout. Twelve groups of 20 trout initially weighing 53 ± 0.6 g/fish were fed semipurified diets containing 19.6 MJ digestible energy per kilogram of dry matter. Twelve levels of phosphorus ranging from 1.03 to 10.96 g/kg dry matter were achieved by replacing inorganic binder with dibasic sodium phosphate in 11 graded levels. Nonlinear responses of trout to increasing dietary phosphorus concentration determined over 53 d were described using exponential functions. Feed intake, growth rate and feed conversion ratio as well as plasma inorganic phosphate concentration increased with increasing dietary phosphorus concentration. The concentrations of phosphorus, calcium, magnesium and potassium in weight gain increased, whereas concentrations of lipids and energy in weight gain decreased with increasing dietary phosphorus concentration. Concentrations of protein and sodium in weight gain were unaffected. Different concentrations of dietary phosphorus were required for achieving 95% of the plateau value determined for desired traits. In growth rate and phosphorus deposition, the required phosphorus concentrations were 3.7 and 5.6 g/kg dry matter, respectively. However, dietary phosphorus was utilized most efficiently (88%) at a dietary concentration of 2.5 g/kg dry matter. At the dietary phosphorus concentration that resulted in maximum phosphorus deposition (5.6 g/kg dry matter), phosphorus utilization was about 60%. Supplemental phosphorus from dibasic sodium phosphate was completely available to trout which must be considered in formulating recommendations. Based on this work, 0.25 g available phosphorus/MJ digestible energy is recommended for trout diets.

This study aimed to distinguish between the single and interactive effects of phosphorus (P), calcium (Ca), and phytase on products of phytate degrad