پردیس کشاورزی و منابع طبیعی دانشگاه تهران Iranian Journal of animal Science 2008-4773 45 3 2014 09 23 Effect of fish oil supplementation on performance, carcass characteristics and meat fatty acids profile of Holstein bulls fed rations whit various proportion alfalfa hay Effect of fish oil supplementation on performance, carcass characteristics and meat fatty acids profile of Holstein bulls fed rations whit various proportion alfalfa hay 209 221 53776 10.22059/ijas.2014.53776 FA Hossein Zakariapour Behnamiri M. Sc. Student, University College of Agriculture and Natural Resources, University of Tehran Mehdi Ganjkhanlou Assistant Professor, University College of Agriculture and Natural Resources, University of Tehran Abolfazl Zali Associate Professor, University College of Agriculture and Natural Resources, University of Tehran Journal Article 2013 04 16 Abstract In this study 36 Holstein bulls (initial BW of 345±61 kg) were randomly assigned to 6 dietary treatments, following a 3×2 factorial arrangement, with 3 concentrate level of fish oil (0, 1 and 2.1% of DM) and 2 levels of alfalfa hay versus corn silage (10 and 20 % of alfalfa hay forage) to investigate the effects of fish oil supplementation and ratio of alfalfa hay and corn silage in diet on performance, carcass characteristics and fatty acids profile. There was no difference in average daily gain, dry matter intake and feed conversion ratio among dietary treatments. The highest level of fish oil had a negative effect on dry matter intake (P<0.01) regardless of alfalfa hay level. In addition, high portion of alfalfa hay forage in diet affected DMI detrimentally, regardless of fish oil levels (P<0.01). Fish oil supplementation increased TBARS value at 2 months of storage (P<0.01). Moreover dietary inclusion of fish oil increased the concentration of Eicosapentaenoic and docosahexaenoic (P<0.01) fatty acids (P<0.01) which subsequently reduced n-6: n-3 (P<0.01). The results of this study indicate that fish oil can be supplemented to feedlot diet to enrich ruminant products by introducing some peroxides production inhibitors in storage period. Furthermore, alfalfa hay can be replaced by corn silage to mitigate the detrimental effect of supplemented fat on dry matter intake. Abstract In this study 36 Holstein bulls (initial BW of 345±61 kg) were randomly assigned to 6 dietary treatments, following a 3×2 factorial arrangement, with 3 concentrate level of fish oil (0, 1 and 2.1% of DM) and 2 levels of alfalfa hay versus corn silage (10 and 20 % of alfalfa hay forage) to investigate the effects of fish oil supplementation and ratio of alfalfa hay and corn silage in diet on performance, carcass characteristics and fatty acids profile. There was no difference in average daily gain, dry matter intake and feed conversion ratio among dietary treatments. The highest level of fish oil had a negative effect on dry matter intake (P<0.01) regardless of alfalfa hay level. In addition, high portion of alfalfa hay forage in diet affected DMI detrimentally, regardless of fish oil levels (P<0.01). Fish oil supplementation increased TBARS value at 2 months of storage (P<0.01). Moreover dietary inclusion of fish oil increased the concentration of Eicosapentaenoic and docosahexaenoic (P<0.01) fatty acids (P<0.01) which subsequently reduced n-6: n-3 (P<0.01). The results of this study indicate that fish oil can be supplemented to feedlot diet to enrich ruminant products by introducing some peroxides production inhibitors in storage period. Furthermore, alfalfa hay can be replaced by corn silage to mitigate the detrimental effect of supplemented fat on dry matter intake. https://ijas.ut.ac.ir/article_53776_a7f311a8920e89ea36e5d68f153f76f2.pdf