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1. The experimental barley samples included 4 hulled and one hull-less low-phytate barley cultivars and two commercial barley varieties as controls. 2. The diets were provided in meal form, with the experimental barley samples constituting the cereal source. Two additional treatments were added for each of the control varieties in which intermediate and recommended levels of phosphorus were provided. 3. A completely randomised design was used with 5 replicates of 5 chicks per treatment. The chicks were grown from 2 to 14 d of age with excreta collected over the subsequent 3 d. 4. Although total phosphorus levels were similar for all barley samples, there were large differences in their phytate content, which ranged from less than 0.5 to 13.8 g/kg. M2 955 hulled barley exhibited the lowest phytate and the highest phosphorus solubility. 5. There was a negative linear relationship between grain phytate and weight gain and with bone ash. The low-phytate hulled barleys M2 955 and the low-phytate hull-less barley (lpa1-1H) gave better feed conversion (8%) than controls. The hull-less low-phytate barley gave significantly higher total phosphorus (18%) and soluble phosphorus retention (23%) than the hull-less control. The low-phytate samples tended to give lower excreta phosphorus levels (total and soluble), but the effect was significant only for the hull-less samples. Amino acid retention was significantly higher for the low-phytate hull-less barley than the control (4%). 6. Overall, the results suggest that using low-phytate barley can result in similar growth while using less supplemental phosphorus, reducing waste phosphorus by more than 50%.

An experiment was conducted to determine the impact of pelleting of rye, dietary salt (.39 and .57%), and crude pentosanase supplementation (0 and .2%) on the viscosity of intestinal contents and the concomitant performance of broiler chicks fed rye-based diets. Each treatment was replicated six times with six birds per replicate. Test diets were fed from 1 day to 3 wk of age, at which time body weight, feed intake, intestinal viscosity, and molecular weight distribution of carbohydrate complexes were determined in fore and hind gut sections. Enzyme supplementation in all treatment combinations significantly increased weight gains and feed conversion efficiency (FCE). Pelleting and salt did not influence weight gain or FCE, although feed intake was increased through the addition of salt. The viscosity of fore and hind gut contents was significantly reduced with pentosanase supplementation, whereas the effects of salt or pelleting were not as clearly defined. Weight gain and FCE correlated with fore but not hind gut viscosity. The viscosity of gut samples was found to be best described by the concentration of carbohydrate complexes with an average molecular weight greater than 500,000 Da. Pentosanase treatment reduced lumenal concentration of these complexes, thereby reducing viscosity and stimulating improvements in growth and FCE.

Wheat (W), triticale (T), hulled barley (HB), hull-less barley (HLB), hulled oats (HO), and hull-less oats (HLO) were gamma irradiated (60Co) at 0, 3, 6 and 9 Mrad to study the effect of irradiation on the nutritional value of cereal grains for chicks. A significant curvilinear relationship between radiation dose and 3-wk body weight of chicks fed irradiated cereals was noted for T, HB, HLB, HO and HLO. Chicks fed W or T showed no effect or lower body weight, respectively, while body weights of chicks fed barley or oat samples were higher with irradiation. The improvement tended to be maximal at the 6 Mrad level. Irradiation significantly improved the gain-to-feed ratio for chicks fed either HO or HLO. Apparent fat retention and tibia ash were higher in chicks fed irradiated HLO than in those fed untreated HLO. In a second experiment chick body weight, apparent amino acid and fat retention, tibia ash, and gain-to-feed ratios were lower in chicks fed autoclaved (121 degrees C for 20 min) barley than in those fed untreated barley. Irradiation (6 Mrad) subsequent to autoclaving barley samples eliminated these effects. Irradiation appears to benefit cereals containing soluble or mucilagenous fiber types as typified by beta-glucan of barley and oats. These fibers appear prone to irradiation-induced depolymerization, as suggested by increased beta-glucan solubility and reduced extract viscosity for irradiated barley and oat samples.

Two experiments were conducted to determine the influence of fat retention on bone mineralization and amino acid retention for broiler chicks fed rye diets containing marginal levels of vitamin D3. In Experiment 1, rye diets containing tallow were supplemented with high vitamin D3, bile salt (sodium taurocholate), or a detergent (sodium lauryl sulphate). Fat retention and tibia ash were improved (P less than .05) with bile salt addition, and tibia ash alone (P less than .05) was improved when high vitamin D3 or the detergent was added to the diet. In Experiment 2, rye diets contained tricaprylin (TC), tristearin (TS), or triolein (TO) as a fat source. Both fat retention (TS less than TO less than TC) and tibia ash (TS less than TC less than TO) showed a significant (P less than .05) treatment effect. The results of both experiments support the hypothesis that the rachitogenic effect of feeding rye may be related to inadequate fat digestion. There was no significant treatment effect on amino acid retention in either experiment. A third experiment indicated a similar bile acid pool size for chicks fed rye as opposed to wheat; however, bile acid concentration of jejunal fluid was lower (P less than .05) for chicks fed rye. A possible microbial involvement in the disturbance of bile acid metabolism was indicated by the capacity of Streptococcus organisms derived from chick small bowel to degrade sodium taurocholate.

Several experiments were conducted to determine the influence of intestinal microflora when rye diets are fed to young chicks. In a conventional environment dietary rye severely depressed growth, amino acid and fat retention, and metatarsal bone ash. These conditions could be effectively alleviated by gamma irradiation of the diet and maintenance in a germ-free environment. In gnotobiotic chicks associated with streptococci dietary rye caused effects similar to those seen in a conventional environment, however the responses were less severe. Since addition of sodium taurocholate improved fat retention from a rye diet to a greater extent than from a wheat diet, a deficiency of conjugated bile salts might contribute to the steatorrhea observed in rye-fed chicks.

Eighty-six broiler diets were studied to develop prediction equations for true metabolizable energy (TME) with nitrogen correction (TMEn) and calculated apparent metabolizable energy (AMEn) from chemical composition. Analyses were selected according to their capacity to represent the terms used in energy calculations, namely, dietary gross energy and energy excreted relative to diet consumed. Dietary gross energy was found to be highly correlated with ether extract alone. Prediction of excreta loss improved substantially with inclusion of two terms: a measurement of fiber [either crude fiber (CF), acid detergent fiber (ADF), or neutral detergent fiber (NDF)] and ash. A composite variable based on starch plus crude protein in place of fiber and ash yielded similar predictions. Accuracy of prediction of TMEn approached that of the biological analysis, but prediction of TME was somewhat less successful. Neutral detergent fiber was less satisfactory as a predictor than ADF or CF. Calculated AMEn was also highly predictable from ether extract or diet gross energy and a measurement of fiber alone; ash apparently was less helpful for AMEn. Previously published equations based on ether extract, ash, and an estimate of fiber gave results similar to the derived equations.

A study was undertaken with chickens to determine the effect of irradiation treatment on the viscosity-inducing properties of polysaccharide components of rye. Three-week body weight, food utilisation, fat retention, and bone ash of chicks were substantially improved by irradiating rye (0 to 10 Mrad) and were maximal at 6 Mrad. Irradiation of the entire diet resulted in no further improvement over irradiating the rye fraction alone. The improved performance coincided with radiation-induced damage to rye polysaccharides, as indicated by reduced viscosity and increased concentrations of reducing sugars.