Effects of targeted phase supplementary feeding on performance of scavenging ecotypes of indigenous chickens in Kenya

Abstract

Indigenous chicken (IC) depend on nutrients they scavenge for growth and egg production. Scavenging alone does not provide sufficient nutrients for both maintenance and high production. Feeding interventions to improve on productivity have been applied uniformly without considering the different growth phases though IC exhibit points of low and high rates of growth along their growth curves. A study was designed to provide a scientific basis for feeding strategies that exploit the physiological adaptations induced by the requirements for improved growth rates. The objectives were to determine the effect of supplementary feeding at exponential growth phase on mature weight, feed intake, feed conversion ratio (FCR) and ecotypes on weight gain and gut morphological characteristics at different growth phases. Feeding trials were run for a period of 21 weeks with supplementation at three growth phases (5- 8weeks (TRT2), 9-14weeks (TRT3) and 15-21weeks (TRT4)) while leaving the chickens to scavenge for the rest of the growing period. The control group (TRT1) was left to scavenge for the entire study period. Three chickens in each phase were randomly selected for examination of histology of digestive system. The weight of the gizzard, length of the small intestines, and number of the villi per cm2 in the three sections of the small intestines were measured. Cost benefit analysis of each treatment was done to identify the feeding regime with the highest mature body weight at the least cost. The results showed a significant difference (P< 0.05) between the treatments where the highest mature body weights were recorded in treatment four (TRT 4) of 1021g for Kakamega (KK) and 1123g for Bondo (BN) ecotypes. However, FCE was highest for TRT3 at 0.241 but the group was not able to maintain high body weights after they were put on scavenging treatment. Treatment significantly affected the intestinal morphology inthe duodenum section only but it had no effect on the jejunum and ileum. The villi population was highest in the duodenum section suggesting that this was the most active section in nutrient absorption. The control group (TRT1) had the highest gizzard weights (10.71g/100g live weight). The study recommended that IC should be supplemented during the final growth phase so as to achieve high body weights while minimizing the cost of supplementation. This feeding strategy can enable the resource poor farmers of IC achieve increased profits from keeping chicken