ABSTRACT

 A study using ninety-nine (99) day old Marshal broiler chicks was conducted to evaluate the effect of garlic powder as natural feed supplement on growth and development of the internal organs, histology of tissues, serum constituents and hematological indices of broiler birds. The birds were randomly assigned to three dietary treatments consisting of thirty-three (33) birds per treatment with eleven (11) birds per replicate. The three dietary treatments were formulated to meet the nutrient requirements of broiler chicks and contained garlic powder supplemented at levels 0%, 1.5% and 2.5% respectively. Growth performance parameters such as feed intake, body weight gain and feed conversion ratio were collected and recorded weekly. Histological sections of the heart, liver, kidney and intestine of the birds were also examined at the end of the experiment. Data collected on different parameters were subjected to Analysis of Variance (ANOVA) using the Statistical Package for Social Science (SPSS version 20). Results showed no significant differences (P>0.05) in growth performance parameters which include final live weight, weight gain, average feed intake and feed conversion ratio. There were significant increases (P<0.05) in relative weights of the heart ( Diet 1, 11.67g; Diet 2, 15.33g and Diet 3, 17 .67g) and likewise its absolute weights. Treatments had no effect (P>0.05) on the dressed weight and weights of wings, drumstick and breast as percentages of the carcass weight. Also, significant decrease (P<0.05) were observed in percentage back cut (Diet I, 17.89%; Diet 2, 15.68% and Diet 3, 14.44%) and abdominal fat (Diet 1, 1.14%; Diet 2, 0.53% and Diet 3, 0.47%) of the carcass. Microbial load of ceaca was significantly different (P<0.05) among treatment while the microbial load of intestine did not show any significant differences (P>0.05) among treatments. Treatments had no significant effect (P>0.05) on Packed cell volume (PCV), Hemoglobin, White blood cell (WBC) and Red blood cell (RBC) values, Mean cell hemoglobin (MCH), Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin Concentration (MCHC). Serum cholesterol, globulin glucose and Alanin aminotranferase (ALT) were significantly different (P<0.05) among the treatments. The microbial load examination of the ceaca and intestine confirmed the antimicrobial properties of garlic. These results showed that garlic supplementation in the diet favored the development of the kidney, lungs, intestine and gizzard. It is concluded that garlic supplementation up to 2.5% showed seemingly optimal performance on the body weight gain and feed conversion ratio and also favored the development of the internal organs. The significant increases observed in the relative weight of the heart suggest that garlic supplementation should be used with caution.