EFFECTS OF INCLUSION OF HULL-LESS BARLEY AND ENZYME SUPPLEMENTATION OF BROILER DIETS ON GROWTH PERFORMANCE, NUTRIENT DIGESTION AND DIETARY METABOLISABLE ENERGY CONTENT

摘要

Two trials were conducted to study the effect of inclusion of hull-less barley and exogenous enzyme to broiler diet on the growth performance, apparent metabolisable energy (AME) and Nutrient digestibility of broiler chickens. The experiments were 3×4 factorial arrangements with three levels of enzyme (0, 300 and 600 g/ton) and four levels of hull-less barley inclusion (0, 10, 20 and 30%) in diet. The digestion trial was performed in battery cage with 648 male broiler chickens where twelve experimental diets were fed to the chickens from 15-21 (starter) and 35-45 (finisher) days of age. In the growth trial, the experimental diets were fed to 960 broiler chicks distributed in 48 pens for a 7-week feeding trial on growing (0-3 weeks), grower (4-5 weeks) and finisher (6-7 weeks) periods. Results showed that increasing the amount of hull_less barley inclusion decreased feed intake and live-weight gain both in the starter and grower period (P.0.01) but, did not significantly influence in finisher period. At the overall rearing period (0-49 days), increasing amount of hull-less barley in diet significantly decreased feed intake, weight gain, and feed conversion ratio (p0.01). Increasing in hull-less barley inclusion rate, increased relative weight of gastrointestinal track, liver and ceca (P0.01) but, did not influence the relative weight of abdominal fat and gizzard as well as the rate of mortality. Hull-less barley inclusion in diet decreased dietary AME and ileal and total tract digestibility of organic matter, crude protein, crude fat and starch in the starting period (p0.01). The hull-less barley inclusion, however, did not significantly influence the nutrient digestibility (exclude crude fat) and AME in the finishing period. Enzyme supplementation did not show improvement in growth performance and nutrient digestibility in broilers. Increasing the amount of hull-less barley in the diet had the most negative effect on nutrient digestion of broilers at starter period and the reduction in broiler performance probably due to the depressed nutrient digestion. The magnitude of the reduction in digestibility and performance depends on the soluble NSPs concentration of hull-less barley containing diets.