In Vitro Viscosity Measurements of Barley Extracts as Predictors of Growth Responses in Chicks Fed Barley-Based Diets Supplemented With a Fungal Enzyme Preparation

Abstract

( < 0.5-mm-mesh screen). When the three extracting methods were compared, method I gave higher readings than method II for high-viscosity barleys, and the reverse was true for low-viscosity barleys. The ranking of the barleys remained the same. Method III gave the lowest viscosity values, perhaps due to active endogenous B-glucanases in water extracts of the raw barley. When different barley cultivars were extracted by method I and subjected to different shear rates the viscosity differences were much more pronounced at the lower shear rates, particularly for high-viscosity barleys. Finally, the same seven barleys were compared in a feeding trial with chickens. The improvement in weight gain due to supplementation with a crude enzyme preparation from Trichoderma viride (Cellulase Tv) ranged from 2 to 4l% (P <0 .05). Similar improvements were obtained for feed consumption, feed-to-gain ratio and dry matter retention (P < 0.05). The highest simple correlation coefficients were between the viscosity of barleys that had been extracted by method I, measured at low shear rates, and relative weight gain (r : 0 .97 , week I plus week 2). The correlation coefficients using low shear rate data were slightly higher than those with high shear rate data.These results indicate that most pronounced differences among barleys were obtained with finely ground samples (<0.5 mm), extracted for one hour at 38'C, using a low pH 1.5 buffer (method I) and assayed at low shear rates. Under these conditions the viscosity data reflected the antinutritive properties of barley, which in turn were reduced or abolished by adding a crude enzyme preparation to the diet.

Effect of β-glucanase/pentosanase enzyme supplementation on the performance of chickens and laying hens fed wheat, barley, naked oats and rye diets

“…The degree of vent soilage was also higher in the rye-fed birds than in birds fed the wheat-and barleycontaining diets (P < 0.0002) but not for those fed the oat diet (P > 0.05). The grain-by-enzyme interaction (P < 0.05) for mortality did not reveal any consistent trend (footnote w, (Table 4), but similar to that previously reported (Rotter et al 1989c). …”

“…Aimonen and Nasi (1991) showed that good-quality oats can substitute for barley in the diet oflaying hens without any negative effects on performance: however enzyme supplementation improved feed conversionby 3%. Classen et al (1988) reported that hulless barley can replace wheat in diets for laying hens, while Campbell and Campbell (1989) (Rotter et al 1989c(Rotter et al , 1990Friesen et al 1991 In order to prevent excitement to all replicated groups only birds from three randomly selected replicates per treatment were weighed and body other cereals showed some differences in performance. Feed intake was higher than for birds fed wheat, barley or oats (P < 0.05).…”

“…Since the hulless barley (Scout) has a higher soluble-B-glucan content and corresponding higher viscosity than the hulled barley (Bedford) the response to dietary p-glucanase was typically larger for the hulless barley (Rotter et al 1989c). Chick performance was also improved when the same crude enzyme preparation was added to the diet containing naked oats.…”

Prediction of the performance of broiler chicks from apparent metabolizable energy and protein digestibility values obtained using a broiler chick bioassay

“…The need for enzyme supplementation of wheat and barley could be determined by measuring the level of NSP. Measuring digesta viscosity itself is labour intensive and routine evaluation would require replacement by an in vitro test such as those suggested by Rotter et al (1989), Bedford and Classen (1993) and Pack and Bedford (1998). Investigation of the chemical differences between wheat and barley samples that produce similar growth but have different AME levels is the subject of further investigation.…”

Enzyme applications for monogastric feeds: A review

“…This application has led to widespread adoption of barley into poultry feeds, an area where barley had previously been used to a very iimited extent. Although most research has been conducted using a chick model, practical feeding trials to market weight have demonstrated the feasibility of this approach in western Canada (Campbell et al 1984;Classen et al 1988), Germany (Jeroch et al 1988(Jeroch et al , 1991, the Soviet Union (Syrvidis et al 1991), Spain (Brufau and Francesch 1991) (Elwinger and Saterby 1987; or eastern Canada (Cave et al 1990) indicated no or a small improvement with enzyme supplementation whereas results from western Canada indicated substantial improvement with enzymatic or irradiation-induced pglucan destruction (Campbell et al , 1987 (Ujiie et al 1991 It has been noted that the differentiation of fiber types among cereals is not absolute and that pentosans comprise a significant portion of the cell wall of barley (Henry 1987 (Rotter et al 1989b;. As occurs with barley, the anti-nutritive effects of feeding rye appear to be less in older birds.…”