Effect of cyromazine inclusion and litter depth on growth performance, nutrient utilization, histopathology and its residues in selected tissues of broiler chickens
Name : Adeleye, oluwafolakemi [View Profile]
Mat no : 06/0040
Year of admission: 2014/2015
Degree awarded: PhD
Date of defence: 19th September, 2018
Increase in the number of poultry production enterprises and urban encroachment have resulted in increasing complaints on obnoxious odour pollution from local residents. Cyromazine has a distinctive quality to control fly larvae that would hatch on poultry manure thus preventing odour. This study determined the effect of cyromazine inclusion and litter depth on performance, nutrient utilization, histopatology and residues in selected tissues of broiler chickens. Structured questionnaires were administered to determine the level of use of cyromazine among poultry farmers. A total of 320 day old broiler chicks (Arbor acre) were used for the feeding study. Diets were formulated to contain 4 levels of cyromazine (0.00, 0.25, 0.50 and 0.75 g/kg) fed to broilers on 2 litter depths (3cm and 5cm). Each dietary treatment had 40 birds and 4 replicates of 10 birds each. Cyromazine inclusion was stopped at 6 weeks to observe a withdrawal period of 7, 14, 21 and 28 days. Two birds per treatment were selected at random at the 6th week for metabolic trial. A bird per replicate was randomly selected, blood samples were collected for haematology and serum indices. At weeks 6, 7, 8, 9 and 10, these birds were slaughtered to harvest tissues for residue determination. Data were collected for feed intake, weight gain, mortality, nutrient utilization, haematology and serum chemistry, histopathology, carcass yield and organ weights. Residues of cyromazine and melamine were also determined in drumstick and thigh. Data were analysed using descriptive statistics for questionnaires and feeding trials were analysed in a Completely Randomized Design in a 2 x 4 factorial arrangement. Results showed that majority (93%) of respondents indicated that cyromazine improved performance and 89.7% showed that it reduced odour. Average daily weight gain and FCR of the cyromazine treated groups were significantly improved (p<0.05) for the dietary treatments while carcass weight did not vary significantly (p>0.05). Litter depth showed no significant (p>0.05) difference in growth performance. Birds on 3cm litter depth had higher (p< 0.05) Crude Protein digestibility (81.39%) than 5cm litter depth (66.07%). Although haematology and serum indices showed no specific pattern in all the weeks, birds fed cyromazine levels above the recommended value (0.50g/kg) elicited an increased erythrocyte and reduced Aspartate aminotransferase levels. The histopathology of kidney was characterised by focal area of interstitial infiltration cells with tubular necrosis and desquamation. The liver was characterised by focal area of lymphoid aggregate with disseminated necrosis of the hepatocytes and inflammatory cells. The spleen also indicated sinuses, trabecular arteries with hyperemia. The melamine residue in meat (thigh and drumstick) were higher (p<0.05) in the treated groups than the control group, which also contained residue of cyromazine. The study concluded that cyromazine inclusion significantly enhanced growth performance, it adversely affected the kidney, liver and spleen and also left residues of cyromazine and melamine in the tissues of broiler chickens even up to 28 days withdrawal period. Therefore for public health implications its use should be monitored and controlled.