GARLIC (ALLIUM SATIVUM) SUPPLEMENTATION IN DIETS OF BROILER CHICKENS AT DIFFERENT FINISHING PERIODS: EFFECTS ON PERFORMANCE CHARACTERISTICS AND MEAT QUALITY

Abstract

Garlic (Allium sativum) is a medicinal herb that improves meat quality but there is limitation to using it as supplement in feed due to high price of garlic and the tasks involved in pulverising it. Therefore; there is the need to explore shorter length of dietary supplementation in broiler chicken diets, hence this study on the effect of supplementary garlic (Allium sativum) at different periods before slaughter on the performance characteristics and meat quality of broiler chickens. A Completely Randomised Experimental design was adopted in which a total of 240 four-week old Aboacre broiler chickens were allocated to five dietary treatments with 12 birds per replicate and four replicates per treatment. Broilers on Treatment A were fed diet that had no garlic inclusion, while broilers on Treatments B, C, D and E were fed supplementary garlic at 5g/kg diet for 1, 2, 3 and 4 weeks before slaughter, respectively. The feeding trial lasted for4 weeks. Data were collected on feed intake, weight gain and feed conversion ratio. Thereafter, 2 female birds were selected randomly per replicate and slaughtered. Blood samples were collected for haematological variables and serum cholesterol contents determination. The moisture and lipid contents, cooking loss, palatability, oxidative stability and bacteria status of meat samples from the chickens were also assessed. The results showed that average weight gain, average feed intake and feed conversion ratio of the birds were not significantly (P>0.05) influenced by the dietary treatments. Also, the carcass, organ, muscle characteristics, and the haematological variables of the chickens were not significantly (P>0.05) affected by garlic supplementation. The serum cholesterol contents of birds on the control diet and for those fed diets containing garlic for one week were significantly (p<0.05) higher than those of birds fed garlic supplemented diets for 2-4 weeks the serum cholesterol contents were 77.81±4.08, 76.33±11.11, 64.73±13.13, 67.67±14.33 and 65.02±8.57 mg/dl for Treatments A, B, C, D and E respectively. The thigh muscle had the highest lipid content (9.52± 1.35%), followed by drumstick muscle (8.25±1.26%) and lowest for breast muscle (6.60±1.06%). Meat from birds on control diet had highest lipid content of 9.12 ±1.59% and was significantly higher (P<0.05) from birds fed garlic supplemented diets (7.85± 1.54, 8.24±1.62, 7.92±1.97 and 7.48±1.49 for treatments B, C, D and E respectively). The extent of oxidation in meat significantly (P<0.05) decreased with increasing period of garlic supplementation. The result for garlic aroma showed that there was no significant difference (P>0.05) due to the treatments but the meat with high garlic aroma score was preferred. Bacteria status of meat samples were similar and was no significant (P>0.05) difference in the bacteria load of meat from the broiler chickens across treatments, but decreased with increasing period of garlic supplementation. It was concluded that feeding diets containing supplementary garlic at 5g/kg diet to broiler chickens for a minimum of 3 weeks to slaughter would reduce serum cholesterol contents and enhance shelf life of meat.