EFFECT OF FISH OIL ON GROWTH PERFORMANCE, PRODUCTIVITY WITH SPECIAL EMPHASIS ON COCCIDIOSIS PREVENTION IN BROILER

Abstract

Chicken coccidiosis is a major threat for emerging poultry industry in Bangladesh. Fish oil (FO) is an important source of omeg-3 polyunsaturated fatty acids (PUFA) which increases immunity to broilers. Fish oil also helps in increasing live weight of broilers. The present investigation was undertaken to determine the influence of dietary FO on growth performance, productivity of broilers. Special emphasis was given to determine the effect of FO in preventing coccidiosis of broilers. A total of 120 commercial broilers were randomly distributed in four groups having three replications per group. Those birds were treated either without FO or with 1%, 2% and 3% FO in regular drinking water. Similar rations were maintained for starter and grower in all treatment groups. The experiment was assigned to three studies. First study was performed to observe the growth and production performance of broilers with FO treatment. In another study, chicks were infected with 104 sporulated oocysts of Eimeria spp. The objective of this study was to evaluate gross, histo-pathological, hematological and biochemical changes in broiler chicken naturally infected with Eimeria. In the last study, changes in different biochemical parameters in broilers serum due to fish oil supplementation were determined. Supplementation of FO in regular drinking water significantly (P<0.01) increased live weight, weight gain at 3rd and 4th week of age of broilers. This increase was higher in 2% and 3% FO supplemented groups compared to others. There was a significant (P<0.01) increase in feed consumption of broilers with increasing level of FO at 4th week of age. Furthermore, cumulative feed conversion (FC) differed significantly (P<0.01) among different groups at 3rd and 4th week of age with better FC in 2% and 3% FO supplemented groups. Data on cost benefit analysis revealed significantly (P<0.05) increased net profit (TK./broiler) and net profit (TK./kg live broiler) in fish oil treatment groups compared to control group. At necropsy, birds which were not treated with FO (control) developed severe gross lesions of coccidiosis such as enlarged and distended caecam with bloody faeces, hemorrhage in intestine etc. However, birds receiving 1% fish oil also demonstrated similar lesions but those were not severe as control group. However no lesions were developed in birds treated with 2% and 3% FO. In histopathology, microgametocyte, macrogamecocyte and second generation schizont of Eimeria spp., severe destruction of epithelium were revealed in caecal and intestinal sections taken from infected birds. Biochemical analysis showed a significant (P<0.05) decrease in level of RBC, Hb and PCV, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and increased level of lymphocyte, monocyte, eosinophil, heterophil in coccidian infected groups. Serum HDL-cholesterol, glucose level were increased and cholesterol, LDL-cholesterol, triglycerides, total protein, albumin, globulin concentrations was decreased significantly (P<0.01) with increasing levels of FO in the broiler diets. This research reveals that supplying 2% or 3% fish oil in regular drinking water of broilers would be effective both in increasing market weight and prevenving coccidiosis of commercial broilers. As a preventive dose, 2% fish oil is recommended