Abstract

An experiment was conducted to evaluate fat sources on growth performance, excreta microbiology and noxious gas emissions in broilers. Experimental birds were reared for 5 weeks and divided into two periods: Starter (0 to 3 weeks) and finisher (4 to 5 weeks). A total of 150 one day old Ross 308 broiler chicks were randomly allocated into five treatments with five replications (six birds per replicate) following a completely randomized design. Dietary treatments included FT1 (corn-soybean meal based basal diet with soybean oil), FT2 (corn-soybean meal based basal diet with chicken fat), FT3 (corn-soybean meal based basal diet with tallow), FT4 (corn-soybean meal based basal diet with tallow and lard) and FT5 (corn-soybean meal based basal diet with pork fat/lard). Overall body weight gain and feed intake did not differ due to addition of different dietary fat sources in broiler diet; however, feed conversion ratio was better in FT1 fed group in comparison to other fat groups (P<0.10). The result of the serum immunoglobulins data indicated that, a significant elevation of serum immunoglobulin M (IgM) was observed after dietary addition of FT1, FT2 and FT5 relative to FT4 (P<0.05) Excreta pH did not differ, however, yeast and mold count was highest in FT4 and FT5 relative to FT1 and FT3 (P<0.05). Excreta noxious gas emissions (NH₃, H₂S and SO₂) were lower in FT1 and FT2 in comparison to other fat groups (P<0.05). Overall, the results of the present study suggested that FT1 and FT2 can be prioritized in the diet of broilers with positive influence on body weight gain and feed efficiency, and substantial reduction of noxious gas emissions. Further detail study could be conducted to investigate the single and combination of different dietary fats (with different ratio) on performance and meat quality indices.

Key words: Broilers, growth performance, immunity, noxious gas emissions.