Effect of feeding of low and high tannin sorghum on carcass quality, skeletal status and histopathology of broiler chicken

Abstract

An experiment was carried out to examine the effect of replacement of maize with three varieties of sorghum (i.e., red, yellow and white) varying in tannin content on carcass quality, skeletal status and histopathology in broilers. The birds were fed on reference and 9 test diets, in which the maize moiety of reference diet was replaced at graded level of 50, 75 and 100% on equal energy content basis with each variety of sorghum. The red sorghum contained relatively higher tannin (1.86%) than yellow (0.57%) and white sorghum. The carcass characteristics (dressing, eviscerated and ready to cook yield) and organ weights (heart, liver, gizzard and pancreas) revealed non significant effects of dietary treatments, except for gizzard weight (% live weight) which was significantly (P<0.01) higher in birds fed on 50% red sorghum diet as compared to reference diet. Organoleptic evaluation of broiler meat of different dietary groups revealed non significant difference for sensory attributes, except for appearance where, 75% white sorghum fed group received significantly (P<0.05) lower score than yellow sorghum fed groups. Leg abnormalities were noticed only in the birds fed on 100% red sorghum incorporated diet with stiff gait, outward bowing of legs, enlargement of hock joints which compelled the birds to sit on the hock joints as they were unable to stand and finally the birds fed on 100% red sorghum diet succumbed up to 5th week of feeding trial. Mortality rate was very high (around 100%) in birds fed on 100% red sorghum diet as compared to those on other diets. Post mortem examination of the birds died from 100% red sorghum fed group revealed poor and pale musculature, severe enlargement of kidney and renal tubules, distended ureters with clear whitish chalky material. It could be concluded that higher level of red sorghum incorporation in the diet of broiler chicken should be with caution and yellow as well as white sorghum can completely replace maize in diet.