نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجو
2 عضو هیات علمی دانشگاه زابل
3 عضو هیات علمی دانشگاه شهید باهنر کرمان
4 عضو هیات علمی پردیس کشاورزی و منابع طبیعی دانشگاه تهران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Oil seeds contain significant amounts of fat and fatty acids unsaturated, andBackground and objectives: Oil seeds contain significant amounts of fat and unsaturated fatty acids, and their use in the diet affects the composition of the fatty acids in various tissues of the body and animals' performance. The aim of this study was to investigate the effects of feeding hemp seed (HS) in diets with low levels of crude protein on feed intake, performance, nutrient digestibility on Baluchi fattening lambs and the possibility of CP reduction in the diets due toadverse effects of unsaturated fatty acids presence in HS on protozoal population and nitrogen recyclingin the rumen.
Materials and methods: Twenty-four Baluchi male lambs, with 24±1 kg body weight (BW) and 4–5 months of age, were used in a completely randomized design experiment. Experimental diets included: 1) control diet with 14% crude protein; 2) diet with 14% crude protein, containing 10% of HS and 3) diet with 12% crude protein containing 10% HS. The fattening period lasted 84 days after a 21-day adaptation period. Dry matter intake, daily body weight gain, cold and hot carcass weights and apparent digestibility were determined. Urine spot sampling was used to determine the purine derivatives. Rumen fluid samples were taken through esophagus-tube connected to vacuum pump before and three hours after morning feeding on the last day of experiment and then pH and ammonia nitrogen (NH3-N) were determined. Data were analyzed using GLM models of the SAS software.
Results: Diets containing HS had significant effect on dry matter intake (DMI), average daily gain (ADG) and final weight of the lambs. The highest DMI and ADG were observed for lambs fed with آُ with 14% crude protein. The final weight in lambs fed with HS with 14 and 12% crude protein diet were 46.11 and 43.03 kg, respectively which was higher than control group with final weight 42 kg. Diets containing HS had significant effect on apparent digestibility of DM and CP by lambs (P <0.05). The concentration of ruminal NH3-N and total protozoa and Holotricha population were significantly affected by experimental diets. The lowest number of ciliate protozoa and the lowest ruminal NH3-N concentration were observed in lambs fed with HS. Microbial protein synthess in lambs fed with HS was higher than control group (35 vs. 31 g/d).
Conclusion: The result of this experiment showed that higher daily body weight, final weight and the microbial protein synthesis were achieved in animals which fed 10 and 14 percent HS. Including 10% of HS to the diet and reducing 2% of CP diet did not have any negative effect on growth performance than control group. In conclusion, based on the results of ADG and final BW and higher microbial protein synthesis including 10% HS as a valuable nutritive feed in the diet of animals is recommended.
کلیدواژهها [English]
Aldai, N., Murray, B.E., Najera, A.I., Troy, D.J., and Osoro, K. 2005. Derivatization of fatty acids and its application for conjugated linoleic acid studies in ruminant meat lipids. Journal of the Science of Food and Agriculture. 85: 1073-1083.
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