الملخص الإنجليزي
The feed industry, in the Sultanate of Oman is stable only through importation of up to 100% of feed ingredients, which increases the cost of formulated diets. This results in the cost of production of livestock in general and poultry in particular becoming relatively higher. Therefore, looking for local and cheap protein and energy feed resources is of high priority especially that the feed cost is increasing globally. In the Sultanate of Oman, fish by-products, such as sardines which are available at reasonable prices and have the potential to be used as a high protein supplements for broiler chicken feeding.
A simple method was used for fish silage making which can be feasibly adopted by local fishermen or small scale farmers. Fish silage was prepared from ground Indian oil sardines (Sardinella longiceps) using inorganic acid (3% hydrochloric acid). Fish silage was dried on crushed corn. A mixture of 85% fish silage: 15% crushed corn ratio was prepared and gave the same crude protein content as in soyabean meal on dry matter basis. Two experiments were conducted to evaluate the use of fish silage as a partial replacements of soyabean meal as a source of protein for growing broiler chicken. The main objective of Experiment 1, ileal digestbility assay was to assess the nutritional value of fish silage compared with soyabean meal for. feeding broiler chicken. The two test ingredients, soybean meal and dried fish silage, were incorporated individually into semi-synthetic diets, as the only source of protein: The digestiblity coefficients of amino acids of fish silage were considerably higher than those of soyabean meal (P<0.001). The lower digestibilties of amino acids for soyabean meal is probably related to the presence of antinutritional factors such trypsin inhibitors. Soyabean meal had lower level of sulphur-containing amino acids than fish silage. For the most important essential amino acids for poultry performance; fish silage contained 66% more methionine; 24% more threonine and 34% more lysine than soyabean meal.
The objective of Experiment 2, growth study, was to evaluate the effect of feeding fish silage on broiler chicken performance and meat quality characteristics effects under closed and open-sided housing systems. Four diets feeding fish silage on broiler chicken performance and meat quality characteristics under closed and open-sided housing systems. Four diets containg (0, 10, 20 and 30% fish silage) were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of
experiment 2, 96 birds were randomly selected and slaughtered to evaluate meat chemical composition and meat quality characteristics. Housing type had significant effects on broiler performnace with birds in closed house performing better than those in open-sided house. Birds in both houses fed diet 10 and 20 % fish silage gained more than other birds fed diet 30% fish silage. However, birds fed the 30 % fish silage diet had lower panel taste score flavor. In general, the current study produced evidence that fish silage can replace up to 20% of soybean meal in broiler diets without affecting performance and sensory quality of broiler meat.
