Ecotype differences in growth and behavioural responses to low energy diets in Tanzanian local chickens

Abstract

A study was conducted to compare growth and behavioural responses to low dietary energy in three chicken
ecotypes at4 weeks old for 7 weeks. 351hens belonging to Kuchi (KU), Ching’wekwe (CH) and Morogoro
medium (MM)ecotypes were allocated to 9 pens in a 3 x 3 factorial design, with 3 replicates. They were fed 3
diets containing 40, 55or 0% less energy than a prescribed control diet. Low dietary energy increased feed
intake but reduced growth rates in all ecotypes. Among40% restricted groups, KU had significantly higher
(p<0.05) weight gains, whereas MM had higher (p<0.05) weight gains and lower feed conversion ratio (FCR) at
55% restriction. Body lengths, shank lengths, chest circumferences and wing spans for KU and CH but not MM
were markedly (p<0.05) reduced for both restricted groups. Foraging and feeding behaviours were higher in
restricted groups of all ecotypes in the third week. MM had least mortality in both restricted groups and
controls. Results of this study show ecotype-specific tolerance to low dietary energy through differences in
growth performance, FCRs and behavioural responses. MM showed better tolerance at the lowest energy level
whereas KU exhibited better performance at 40% and control energy levels.