ルーメン内における窒素代謝の量的考察

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It has been suggested that the protein and the other nitrogenous compounds are degraded by the vast numbers of ruminal micro-organisms in the rumen. The ammonia and the other end products of fermentation can be utilized by ruminal micro-organisms and be made up to their own body protein. The processes of the degradation of feed protein and the resynthesis to the microorganisms body protein are carried out simultaneously in the rumen. Therefore, the amount of the whole protein in the rumen will decrease or increase depending on the results of protein degradation and resynthesis of it from the other nitrogenous compounds. The experiments described in this paper provide the weight change of the protein and the other nitrogenous compounds in the rumen of sheep under various feeding conditions by using reticulo-omasal orifice plugging technique. Furthermore, observations were made on the protein synthesis and breakdown in the rumen with urea feeding by using same technique. Moreover, the alteration of amino acid composition of protein in the rumen contents were determined. In addition, absorptive rate of ammonia through the rumen epithelium and toxicity of absorbed ammonia were discussed. I Method for determination of whole rumen contents. One corridale sheep, fitted with large rumen fistula was used in these studies. The rumen fistula was closed by plastic plate and foam rubber cannula. In order to prevent the passage of the rumen contents into the abomasum, the reticulo-omasal orifice plugging technique was deviced. The preventation of passage of the rumen contents into the abomasum by the method of reticulo-omasal orifice plugging, were confirmed by the recovery experiments of Cr₂O₃ and PEG from the rumen contents. II Absorption of ammonia through the rumen epithelium. The absorptive rate of ammonia through the rumen epithelium was determined under the reticulo-omasal orifice plugging condition. It was observed that 1.0 to 2.1 g of ammonia were absorbed from rumen in one hour with the concentration of ammonia nitrogen 100 to 200 mg/dl in the rumen. The evidence thus obtained supports the suggestion that a large amounts of ammonia were readily absorbed from the rumen epithelium. III Fluctuation of nitrogenous compounds in the rumen and rumen fermentation. The experiments were performed on a sheep subjected to nine different feeds. Observations were made on fluctuation of nitrogenous compounds, VFA and gas production ability of the rumen contents in nine hours after feeding. The total nitrogen in the rumen was decreased markedly in readily fermentable and high protein feeding. On the other hand, total nitrogen were slightly decreased in low protein and hardly fermentable feeds, and was increased slightly with hay fed condition. The results obtained suggests that the decreasing of total nitrogen were due to the absorption of ammonia nitrogen through the rumen epithelium. The protein nitrogen was increased with low protein and hardly fermentable feeds in the rumen. The experiments which showed the increase of the protein nitrogen in the rumen were low protein feeds and were not contained the concentrates. The decreasing of the protein nitrogen were observed with the experiments which contained high protein concentrates. However, the decreasing rate of protein nitrogen differed with the addition of roughages. The maximum value of concentrate of the ammonia nitrogen was 46 mg/dl in the experiment which showed increasing of protein in the rumen. The experiments which observed decreasing of protein in the rumen, the maximum value of ammonia nitrogen was 136 mg/dl. The production of VFA were nearly paralleled with the increasingg rate of protein and ammonia production in the rumen. The gas production ability of the rumen contents in vitro were showed high values just after the feeding and decreased in nine hours experimetal periods in the case of protein decreased experiments. From the results of these experiments, it seems most reasonable to conclude that the main factors for the fluctuation of protein in the rumen are the protein level and the rate of fermentation of each feeds. IV Qualitative fluctuation of protein in the rumen. The fluctuation of the amino acid composition of the protein in the rumen contents were determined. No marked difference of the amino acid composition could be observed between hay and rumen contents. These results suggest that the amino acid composition of hay and rumen micro-organisms were not differed markedly. However, the basic amino acids were slightly increased in the rumen in contrast with hay. V Effect of urea on the protein synthesis in the rumen. The fluctuation of protein in the rumen was determined by the addition of urea to the four various protein and NFE level feeds. The protein nitrogen was increased only in the addition of urea to the low protein and high NFE feed. The protein nitrogen was not increased by the addition of urea in the other feeds. VI Disposal abiliy of absorbed ammonia. The ammonia nitrogen were absorbed through the rumen epithelium in short period. The toxic syndrom of ammonia which occured by the absorption of ammonia from the rumen was determined with the method of infusion of ammonia into the portal vein. The sheeps were brought to death by the infusion of ammonia nitrogen over 30 mg/hr. kg into the portal vein.
信州大学農学部の論文
1966-12-25

ルーメン内における窒素代謝の量的考察

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信州大学農学部 | 論文

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