Effect of Boldenone undecylenate injection and dietary protein level on fattening performance, nutrient digestibility and carcass characteristics of Romanov-Moghani crossbred lambs
IntroductionBoldenone undecylenate is an anabolic steroid that stimulates protein production. Boldenone injection can increase muscle size in lambs and reduce their nutritional needs and increase feed intake. Anabolic steroids increase protein synthesis in the muscles of tissues; furthermore, high levels of diet protein can increase the amino acid for the tissues and further synthesize the protein by the androgens. The aim of this study was to investigate the fattening performance, nutrient digestibility, and carcass characteristics of Romanov-Moghani crossbred lambs influenced by boldenone undecylenate injection and level of dietary protein.
Material and methodsTwenty male lambs were used in a randomized completely design with factorial arrangement (2×2) of the treatments. The main experimental effects were effect of boldenone undecylenate (no injection or injection of 5 mg/kg BW of boldenone) and effect of diet protein level (12 or 16 percent per DM of the diet). The experiment was continued for 75 days. Lambs were classified according to body weight and diets were fed to lambs twice a day at 9 a.m. and 17 p.m. In order to evaluate the performance, lambs were weighed every two weeks and daily weight gain was calculated by the subtraction. Feed intake was determined from the difference between the offered feed and the refusal. At the end of the experiment, all lambs were slaughtered and their carcass characteristics were measured. Blood sampling were taken monthly (two times) from jugular vein in two stages from all lambs three hours after morning meal and blood plasma was separated by centrifuging (3500 rpm for 10 min) and kept at -20 ° C till the analysis.
Results and discussionResults showed that total average daily gain changed significantly by boldenone undecylenate injection (P<0.05). Feed conversion ratio for total period and average total weight gain were not affected by increased dietary protein level. Total average daily gain and weight at the end of fattening period were not changed significantly by the dietary protein. Total dry matter intake (DMI) in Romanov-Moghani lambs was not affected by boldenone injection and levels of dietary protein. The carcass characteristics of lambs were not significantly affected by hormonal injection or dietary protein levels. The results showed that the effects of hormonal injection and dietary protein change were not significant on nutrients digestibility, except for crude protein digestibility (P<0.01). Blood urea nitrogen concentration was influenced by hormonal injections during the first month (hormone injection period) and injection of hormone caused a significant decrease in blood urea nitrogen (P<0.05). Blood protein concentration increased significantly at the end of the first month (hormone injection period), (P<0.05). The serum protein level was affected by the interaction of hormone with protein (P<0.05). Diet protein has a significant effect on blood glucose concentration (P<0.05). Triglyceride and was significantly altered with hormonal injections in the first month (hormone injection period), (P<0.05).
ConclusionBased on the results, Administration of Boldenone undecylenate and the use of different level of dietary protein changes the protein base metabolism in the crossbred lambs and more energy is used to synthesize and storage protein in tissues.
Journal of Animal Science Research, Volume:28 Issue:4, 2019
127 - 140
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