T. A. Scott

Effect of cultivar and environment on the feeding value of Western Canadian wheat and barley samples with and without enzyme supplementation

The feeding value ofnine wheat cultivars grown in replicate in three locations in each of two crop years, and 14 barley cultivars grown in seven locations over three crop years was tested with or without an appropriate commercial enzyme using a broiler chick bioassay. Four pens of six male broilers were fed mash diets containing 80% of the test cereal with or without enzyme from 4 to 17 d. Digestibilities were determined using an acid insoluble ash marker at 1.1% of diet. Significant intraclass correlation coefficients between duplicate wheat samples suggested a common effect of the location, but their low to moderate values suggested the presence of random variation or variation due to unique growing conditions within location. For both wheat and barley samples, the growing location affected the feeding value of the cereal grain and subsequent broiler chick performance. Durum wheat cultivars had higher feeding values than that of other wheat classes, both with and without enzyme supplementation, and the ...

The effect of wheat cultivar, growing environment, and enzyme supplementation on digestibility of amino acids by broilers

Fifty-four samples of wheat, representing duplicate samples of nine varieties grown in three environments, were included in chick bioassays using rapidly growing broilers, complete diets, and enzyme supplementation to remove the deleterious effects of non-starch polysaccharides. An insoluble ash marker was included in the diets, which allowed calculation of apparent digestibilities of CP and AA in the grain from analysis of the ileal contents obtained after sacrifice of the chicks at 17 d of age. The wheat cultivars contained from 13.5 to 16.8% CP and differed in the percentage of specific AA, with Pro, Glu and Phe making up proportionately larger parts of high CP samples than low CP samples. Without enzyme supplementation, the digestibility of CP varied from 83 to 88% and that of specific AA from 76 to 94%, determined in part by the class and variety of wheat. Xylanase enzyme supplementation improved the digestibility of protein by an average of 4%, and reduced the differences in digestibility between wh...

IMPACT OF WET FEEDING WHEAT-BASED DIETS WITH OR WITHOUT ENZYME ON BROILER CHICK PERFORMANCE

Two studies were conducted to determine the effect of wheat source on voluntary feed intake when diets were offered in a wet or dry form. The first experiment was designed to establish if a mould inhibitor was necessary. The second experiment allowed more extensive screening of wheat types to determine if there is a genetic component in wheat that explains the differences observed in exp. 1. Experiment 1 was based on two wheat cultivars [Hard Red Spring (HRS) and Durum]. Each wheat was ground, one portion was used as is, the other pelleted and re-ground. The four wheat sources were included at 80% of a standard bioassay diet (with enzyme) and each diet was fed with or without propionic acid. The eight diets were fed ad libitum as is or with 1.2 g water per gram of feed. The wet diets were prepared daily and all diets were fed to four groups of six male broilers from 1 to 17 d of age. The second experiment utilized three cultivars each of HRS and Durum wheat fed in similar bioassay diets with no pre-pellet...

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

Samples of wheat (54) and barley (87) were included in a series of broiler chick bioassays. For each cereal, fed at 80% of a basal diet with or without enzyme, apparent metabolizable energy (AME), retained nitrogen, digesta viscosity, excreta dry matter (DM), and broiler performance (feed intake, body weight [BW] gain, and feed conversion) were measured. Correlation coefficients were calculated between the predictor and the performance variables, separated according to whether or not the diets included feed enzymes. Some correlations between measures of AME and BW, feed efficiency, and to a lesser degree feed intake were significant, but none were high. The correlation coefficients were higher when feeds were not supplemented with an enzyme because enzyme supplementation reduced the variation in both AME and performance by reducing the antinutritive effects of non-starch polysaccharides (NSP). Including a measure of voluntary intake in AME (AME level multiplied by feed intake) resulted in higher correlati...

The effect of adding exogenous phytase to nutrient-reduced corn- and wheat-based diets on performance and egg quality of two strains of laying hens

A laying trial was conducted in which ISA-Brown and ISA-White hens were fed diets based on corn or wheat that had been pelleted to eliminate endogenous phytase. Control diets were formulated to contain adequate levels of all nutrients. Nutrient-reduced diets were formulated to account for nutrients released by the phytase. To formulate these diets, phytase was entered into the matrix with a value, on a weight basis, of 1,173% for CP (60.5% for lys, 29.4% for met plus cys, 40.0% for thr), 39 900 kcal kg–1 for AME, 666% for Ca, and 333% for available P. A negative control diet was based on the modified formulation but did not include phytase. Differences between diets were observed for tibia ash, and Ca and P in the ash, as well as for BW and measures of egg quality. Egg production likely provided the best measure of the adequacy of P nutrition. In the final period of production, feed intake and egg production of hens fed the nutrient-reduced corn-based diet without enzyme was lower (P < 0.05) than that of ...

Measurements of enzyme response with hulless barley based diets full-fed to Leghorn and broiler chicks or restricted-fed broiler chicks

Broiler chicks fed diets high in soluble non-starch polysaccharides (NSP; e.g., wheat- and/or barley-based diets) have a higher capacity to ingest, digest and absorb nutrients when diets are supplemented with appropriate NSP enzymes. However, this same enzyme response is typically reduced or non-significant in older birds, Leghorn chicks and turkey poults. We hypothesise that the enzyme response in the latter classes of poultry is reduced because feed intake is lower in comparison to feed intake by broilers. In the present study, the hypothesis that restricted feeding of broilers would reduce the enzyme response typically observed in full-fed broilers was tested. Two experiments were conducted to determine the feeding value of hulless barley supplemented or not supplemented with enzyme (Avizyme 1100, Finnfeeds Int, UK). In Study 1, eight sources of hulless barley were included at 80% in each diet and fed to four groups of six male broilers or Leghorn chicks from 4 to 17 d of age. The response to enzyme in...

The effect of storage of cereal grain and enzyme supplementation on measurements of AME and broiler chick performance

There is a concern that feeding newly harvested cereal grain results in poor performance in poultry. A broiler chick apparent metabolizable energy (AME) bioassay was used to measure changes in feeding value of wheat (n = 14), hulless (n = 10) and hulled (n = 14) barley with or without a commercial enzyme appropriate for wheat- or barley-based diets. In the broiler chick bioassay, four pens of six male broiler chicks were fed ad lib, from 4 to 17 d, diets containing 80% of a test cereal grain and a high-protein basal mixture containing 1% “celite” as an acid-insoluble ash marker. Each of the cereal-grain-based diets, with or without enzyme, was tested within 3 mo of harvest and again 6 mo later. With cereal grain storage there were consistent (P < 0.05) increases in feed intake (FI) between 4 and 17 d and body weight (BW) at 17 d of age with wheat-based diets fed wit h (12.5 and 16.9%, respectively, for FI and BW) or without (16.1 and 22.7%) enzyme. In hulless barley diets without enzyme, there was a signi...

Effect of feed form, formulation, and restriction on the performance of laying hens

A laying trial was performed with 1440 DeKalb® hens caged at 18 wk of age to test the effect of feed form (expanded pellets or mash) and type of formulation (for crude protein [CP] or for specific amino acids[AA]), and five levels of feed restriction applied at either 24 wk or 32 wk of age. Formulation for CP rather than AA content resulted in 4.4% greater egg production and 7.1% greater production of egg mass in hens fed mash and 4.0% better feed efficiency in hens fed both mash and pellets. Hens fed mash had 2.3% higher feed consumption, suggesting that the hens may prefer mash. Feed restriction reduced body weight and hen–day egg production proportionate to the restriction level, but egg weight was reduced only slightly. These data suggest that care should be exercised in formulating for AA content rather than for CP, especially if feed intake is reduced. This strain of hens was very successful at regulating its feed intake for maximum production, and even a slight feed restriction produced a negative ...

The effect of phosphorus, phytase enzyme, and calcium on the performance of layers fed wheat-based diets.

A trial was performed to test the effects of two levels of Ca (3.7 and 4.0%), two levels of available P (0.2 and 0.4% until 55 wk, 0.11 and 0.22% from 55 to 67 wk), and three levels of phytase enzyme (0, 250 and 500 FTU kg−1) on the performance of laying hens fed diets based on wheat and soybean meal. Phytase supplementation had only small effects, likely because the endogenous phytase in the wheat liberated sufficient phytate-bound P to compensate for only marginally deficient levels. In contrast to what has been found with corn-based rations, there were no negative effects of high levels of AP or of enzyme, suggesting that the effect of exogenous phytase was more complex than a simple liberation of phytate P. Endogenous phytase should be considered when formulating rations based on wheat. Key words: Phytase, layers, wheat, phosphorus, calcium

Assessment of energy levels in feedstuffs for poultry

Abstract The feeding industry is still faced with finding an answer to the most fundamental question, ‘how much energy is available in feedstuffs?’. The Agassiz chick bioassay is designed to improve the sensitivity of bioassay measurements by including an assessment of the birds physiological and anatomical response to a feedstuff. The bioassay compares identical feeds with and without supplemental enzyme, at two different ages, using excreta and ileal digesta collection methods. Differences in energy value determined with these different methods will help us identify those factors in cereals which influence digestibility. The bioassay samples will be used by other laboratories to validate their lab-bench procedures for measuring feeding value of cereals. These lab-bench procedures (near-infra-red, carbohydrate profiling, etc.) would allow feed manufacturers to identify individual cereal feeding value quickly, pay accordingly and/or make necessary adjustments (e.g. add specific quantities and types of enzymes or employ different processing methods) to improve feeding value. Rapid assessment of feeding value of cereal grains will allow accurate feed formulation, which will, in turn, reduce the need to over-formulate. Reductions in over-formulation of nutrients will reduce input costs and excretion of undigested nutrients which potentially increase environmental pollution. Similarly, rapid procedures of identifying feeding value will be a useful tool by plant breeders in selecting new cultivars of cereals.