Effect of enzyme supplementation and processing of high fibre diet on the performance of broilers
Abstract
Two experiments of 42 days duration, each, were conducted on day old 320 and 520 commercial broiler chicks to evaluate the effect of crude fibre levels, enzyme supplementation, feed particle sizes and pelleting on their performance. In the first experiment, the 320 chicks were randomly divided into eight treatments. Each treatment had two replications with 20 birds in each replication. The diets were isoproteinic. Metabolizable energy (ME) in 5% CF (T1) diet was as per BIS (1992). In diets T2 (7% CF), T3 (9% CF) and T4 (11% CF) the ME was decreased due to increased CF levels. The diets T5, T6, T7, T8 were formulated by adding commercial multienzyme to T1, T2, T3 and T4 @ 100 g/quintal of feed.
The average body weight gain in 42 days of growth trial was 1566.25, 1789.05, 1753.27, 1738.13, 1668.16, 1805.25, 1825.33 and 1754.55g in treatments T1, T2, T3, T4, T5, T6, T7 and T8, respectively, being significantly (P<0.05) higher at higher crude fibre levels than control group (T1). Feed intake was also significantly (P<0.05) higher at higher crude fibre levels than T1. Enzyme supplementation resulted in non-significant improvement in body weight gain, feed intake and FCR than those of corresponding non supplemented groups.
Dry matter and nitrogen metabolizability was significantly lowered in T4 than T1, T2, T3 diets and enzyme supplementation resulted in improved dry matter and nitrogen metabolizability. Calcium and phosphorus retention were not affected significantly (P<0.05) due to CF levels. However, phosphorus retention was significantly (P<0.05) higher in enzyme supplemented diets. Enzyme supplementation also resulted in significant (P<0.05) improvement in MEn and GE metabolizability. Increasing CF levels resulted in significant (P<0.05) and gradual increase
in intestinal viscosity, which was significantly (P<0.05) decreased due to enzyme supplementation.
The relative length and weight of intestine and the weight of pancreas were significantly (P<0.05) higher at higher CF level, which were significantly (P<0.05) decreased due to enzyme supplementation. Mortality (2.18%) was not related to dietary treatments. Increasing the CF level of diet was found to be economical and enzyme supplementation further improved the profit. The maximum profit was observed in T7 treatment.
In the second experiment, 9% CF, was kept constant except in T1. In T2, T3, T4 and T5 diets feed ingredients were ground through 3, 5, 6 and 3+6mm (1:1) sieves, Geometric mean diameter (GMD) of particle in T2, T3, T4, T5 was 669, 905, 1142 and 913, respectively. T2, T3, T4 and T5 diets were supplemented with commercial multienzyme and designated as T6, T7, T8 and T9, respectively. T2, T3, T4 and T5 diets were also pelleted and designated as T10, T11, T12 and T13, respectively. Electricity consumption in grinding was estimated and was found to be decreased with increased sieve size of hammer mill. Highest PDI was observed in pellets of feed having 669 GMD.
The body weight gain at 905 GMD was non-significantly higher than other particle sizes. Enzyme supplementation and pelleting also resulted in non-significant improvement in body weight gain than mash, un-supplemented groups and significantly (P<0.05) higher than control (T1). However in pelleting diets lower body weight gain was observed than enzyme supplemented diets. Feed intake was not affected by dietary treatments. FCR was non-significantly improved due to enzyme supplementation or pelleting of diets.
Dry matter and nitrogen metabolizability was significantly (P<0.05) high at 905 GMD than 669 GMD and comparable to control (T1, 784 GMD). Enzyme supplemented or pelleted diets resulted in significantly (P<0.05) higher dry matter metabolizability, MEn and GE metabolizability than un-supplemented mash groups. Phosphorus retention was found significantly (P<0.05) higher in 905 GMD than 669 GMD and even control (T1). Particle size of 905 GMD was found to be most economical and enzyme supplementation further improved the profit.
It can be concluded that feeding a diet having particle size 905 GMD, 9 percent crude fibre and supplementing with enzyme economizes the broiler production.