نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی دانشکده کشاورزی، دانشگاه لرستان
2 دانش آموخته کارشناسی ارشد گروه علوم دامی دانشکده کشاورزی دانشگاه لرستان خرم آباد
3 عضو هیئت علمی گروه علوم دامی دانشگاه لرستان
4 دانشیار گروه علوم دامی دانشکده کشاورزی دانشگاه لرستان خرم آباد
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and purpose: Feeding high levels of dietary protein and protein breakdown in the rumen increases the concentration of ammonia, which reduces the efficiency of using nitrogen for milk production. Feeding too much protein causes nitrogen accumulation in the environment. Ammonia created as a result of excretion of urea through the urine of animals can affect the quality of soil and water. One of the harmful compounds for the ozone layer is ammonia. Therefore, by balancing the rations of dairy cows to provide limiting amino acids, it is possible to improve the production response to low-protein diets without increasing urinary nitrogen excretion. Limiting amino acids methionine and lysine have positive effects on livestock. The purpose of this research was to study the effect of supplementing the ration of dairy cows with lysine, methionine and their calcium analogues on parameters of gas production, microbial enzyme activity and rumen fermentation in laboratory conditions.
Materials and methods: In order to investigate the use of lysine and methionine supplements and their calcium analogues on parameters of gas production, fermentation and rumen enzyme activity in vitro in a completely randomized experimental design with 7 treatments, 12 repetitions and in 3 separate periods with treatments The following was done: 1) control diet, 2) control diet + 0.30% lysine (lysine hydrochloride), 3) control diet + 0.30% lysine (lysine analog), 4) control diet + 0.30% methionine. DL-methionine), 5) control diet + 0.30% methionine (methionine analog), 6) control diet + 0.30% methionine (methionine analog) + 0.30% lysine (lysine analog) and 7) control diet + It was 0.30 percent methionine (DL-methionine) + 0.30 lysine (lysine hydrochloride). All diets were incubated for 96 hours and gas production was recorded at 2, 4, 8, 16, 24, 48, 72 and 96 hours.
Findings: The highest gas production in 16 hours after incubation was related to the treatment receiving lysine hydrochloride and the lowest gas production was related to the treatment receiving DLmethionine (P<0.05). Also, a similar trend was observed in other times and total gas production (P<0.05). Gas produced at all times in the treatment receiving the calcium analogue of lysine and the treatment receiving the calcium analogue of lysine plus the calcium analogue of methionine did not show a significant difference with the control treatment (P<0.05). Digestibility of organic matter, metabolizable energy and concentration of volatile fatty acids were higher in the lysine hydrochloride treatment than in the control treatment (P<0.05). Ammonia concentration in the treatments receiving calcium analogue of lysine or methionine was similar to the control treatment, but adding lysine hydrochloride and DL-methionine to the control diet significantly increased ammonia concentration (P<0.05). The activity of microbial enzymes was not affected by the treatments (P<0.05).
Conclusion: The use of calcium analogue of lysine and methionine can be a promising method to improve the limitation of amino acids (lysine and methionine) in dairy cattle nutrition without any negative effect on rumen fermentation.
کلیدواژه‌ها [English]
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