Effect of Dietary Inclusion of Rice Husk Supplemented with Commercial Enzymes on Performance, Nutrient Retention and Gastro-intestinal Tract Characteristics of Arbor Acres Broilers

Abstract

Aims: This experiment was carried out to assess the effect of dietary inclusion of rice husk supplemented with commercial enzyme on performance, nutrient retention and gastro-intestinal tract characteristics of chicken broilers. The experimental design was a 2×4 factorial combination of two dietary level of rice husk (0 or 25%) with four levels of different commercial enzymes 0E (without enzyme 0ppm), 100E (100ppm of Phytase), 150E (150 ppm of Nutrase xyla), or 350E (350ppm of Grindazyme). Rice husk was added at the expense of maize in the control diet, and each experimental diet was tested during a 56-day feeding trial in triplicate. One hundred and ninety-two (192) one-day old unsexed Arbor acres chicks were used in the trial. Experimental diets and water were supplied ad-libitum to the birds from day the first day to day 56 and chicks were subjected to the recommended routine vaccination programmed. A nutrient digestibility trial was undertaken when the birds were 3 weeks old. At the end of the feeding trial, 3 birds per replicate were randomly selected, euthanatized by neck decapitation, then eviscerated, and the crop, proventriculus, gizzard, liver and pancreas weights were determined. The results showed that an increase in the dietary level of rice husk without commercial enzyme supplementation significantly decreased (P<0.05) weight gain, feed conversion ratio and nutrient digestibility. There were significant (P<0.05) interactions between dietary levels of rice husk and the inclusion of commercial enzymes on performance, nutrient digestibility and gastro-intestinal tract characteristics of chicks. Hypertrophy of the digestive organs was observed in birds fed rice husk without enzyme supplementation. However, this effect was attenuated with the inclusion of commercial enzymes. Results obtained showed that birds fed rice husk diets supplemented with commercial enzymes performed better in all parameters tested than those fed rice husk diets without commercial enzyme. The use of commercial enzyme is advantageous in the utilization of high-fibre diets for chicks. The dietary supplementation with commercial enzymes increased the weight gain, feed conversion ratio and improved nutrient digestibility in broilers, which supposes a beneficial reduction in the production costs