Studies on the metabolism of volatile fatty acids in hens

Transcription

1 Studies on the metabolism of volatile fatty acids in hens II. An effect of feedstuff on the production of V.F. As in the alimentary tract of egg laying hens Eiichi WATANABE and Akira CHIBA (Miyagi Agriculture College, Sendai) (Received for Publication on December 16, 1968) In our previous paper4), it has been observed that the presence or absorption of volatile fatty acids (V.F.As) was confirmed in the various alimentary tract of laying and nonlaying hens. The result indicates that V.F.As were produced in the alimentary tract and also suggests that the produced V.F.As could be utilized as energy source in the various tissues. A series of experiments was attempted to study a relationship between the composition of feedstuff and productivity of V.F.As in hens. In this experiment, the effect of fat free feedstuff on V.F.As production and the utility of V.F.As were surveyed in laying hens. Materials and Methods Experimental animals: Four laying White Leghorn hens, weighing from 1710 to 1780 grams were used. Those birds were 10 months after they laid their first eggs and their average egg production during two months just before begining the experiment was 86 percent. Preparation of fat free diet: The feedstuff used for the preparation of fat free diet was the same feed used for the previous experiment. The feed ingredient and chemical compositions are given in Table 1 and 2. A fat free diet was prepared by extraction of fat with ethylether. Chemical compositions of the diet are shown in Table 3. Table 1. Composition of experimental diet (%) * Vitamin premix Vitamin A IU. Vitamin D IU. Vitamin E 2500IU. Riboflavin 20.0 g. Niacin 4.0g. Cholin Chloride 50.0g. Calcium Pantothenate 5.0g. Vitamin Bia 0.05 g. Folic acid 50.0mg. Biotin 50.0mg. Fe 7.0g. Zn 1.4g. Cu 1.4g. Co 0.2g. per kg. Jap. J. Zootech. Sci., 40, (4):

2 Metabolism of V.F. As in hens Table 2. The chemical composition of feed (%) * N.F.E.: Nitrogen free extracts ** TDN: Total digestible nutrients Table 3. Chemical composition of fat free diet (%). * N.F.E.: Nitrogen free extracts ** TDN: Total digestible nutrients Preparation of starch solution: 10 grams of purified soluble starch was dissolved in 50ml. distilled water and heated in water bath. Starch solution was freshly prepared every time. Procedures for feeding: 4 birds were divided into two groups. (one group for fat free diet and another group for starch feed). They are reared in single cage. Experiment was conducted during the period from May 1, 1967 to May 31, Fig. 1. Changes of body weight, body temperature and consumed volume of fat free diet in the experimental animals 181

3 WATANABE CHIBA Prior to begining of the experiment the birds were drugged orally chloromycetin and starved for 24 hours with water supply. In group 1, a fat free diet was fed 150 grams daily per bird at 9.00 A.M. and the amount of diet consumed was determined by cleaning up the previous day's diet fed. In group 2, starch feed was fed 50ml. twice a day using a cannula. Prior to the administration of test diet, the birds were recorded their body weights and body temperatures (rectum temp.). Their body weights and body temperatures during the periods of experiment are shown in Fig. 1. Sampling: Blood samples were taken according to the method reported in our previous paper4). Serum was used for the determination of V.F.As in blood flow. Contents of alimentary tract: After taking blood samples, birds were autopsied and the part of each alimentary tract was ligated to avoid flow out of the contents and then immediatly removed. The contents were collected to measure flask and total weight of the contents was recorded. The contents were added by 200ml. of distilled water and the mixture was centrifuged at 3000 r.p.m. for 15 minutes, and supernatant was used for the estimation of V.F.As. The estimation of V.F.As in blood serum and the contents of alimentary tract: Microdiffusion analysis reported by CONWAY1) was used for the determination of V.F.As fraction- The sample of alimentary tract for the determination of fraction of V.F.As was deproteinized by the method reported by HADEN2) and distilled for extraction of V.F.As fraction. Identification of V.F.As was performed with paperchromatography. Results and Discussion 1. Concentration of V.F.As of alimentary tract of the hens fed a fat free diet. The results are shown in Table 4. The value of V.F.As was calculated as the amount of acetic acid. (a) A total amount of the contents of alimentary tract varied with the part of tract. In the egg laying hen, average weight of the contents was 61.0 grams and it ranged from to grams. Average concentration of V.F.As in crop sac, muscullar stomach, pars descendens, pars ascendens of duodenum, pars cranialis, pars caudalis of jejunum and ileum, caecum, colon and rectum were , 42.32, 88.39, , , 23.27, and mg/g, respectively. (b) Average net amount of V.F.As: In crop sac, a highest average net amount of V.F.As was recorded. It was also observed that the net amounts of V.F.As in the muscular stomach, ileum (including jejunum) and caecum showed higher values in comparison with those of another parts of the tract. It was confirmed that an average net amount of V.F.As in alimentary tract was 8.25 grams as acetic acid ranging from 7.6 to 9.2 grams and these values were the same as reported in previous papers3). A high concentration of V.F.As in caecum may be due to the active fermentation of feedstuffs in each tract. It was also guessed that a high concentration of V.F.As in duodenum might be resulted from a carrying over of V.F.As from crop sac. The highest net amount of V.F.As in the crop sac may suggest that crop sac has an ability of the V.F.As fermentation. The fermentation and absorption of the crop sac of hen 182

4 Metabolism of V.F.As in hens

5 are very interesting. In the hens fed fat free diet, a total amount of V.F.As in alimentary tract was about the same volume as in the hens which had been fed formula feed. It seems to be obvious that a fat free diet did not affect the fermentation of V.F.As in alimentary tract. 2. A concentration of V.F.As in the hens fed soluble starch diet. The results are given in Table 5. Total contents of the each tract were less than those of hens which had been fed fat free diet or nonlaying hens. It was found that a concentration of V.F.As was less than those of laying or nonlaying hens and hens fed fat free diet. Average net amount of V.F.As in the crop sac, pars acendens of duodenum, pars cranialis of ileum, caecum, colon rectum was 3.06, 0.8, 0.69, 1.02 and 0.71 grams respectively. In the hens which had been fed fat free diet a total amount of V.F.As in alimentary tract was ranged from 8. 0 to 9.5 grams and it's value was in proportion to 16 to 17 percent of the contents of tract. It was also shown that V.F.As production in the alimentary tract did not differ in the egg laying hens fed starch diet. 3. Identification of V.F.As fraction. In order to identify nature of V.F.As fraction, paper chromatography was performed on the supernatant of the contents of tract. As is shown in Fig 2, a spot of acetic acid and propionic acid was identified. It was clearly shown that V.F.As produced in alimentary tract of hens are acetic and propionic acid. 4. A concentration of V.F.As in blood serum. The results are shown in table 6. In the hens which had been fed fat free diet or starch diet, concentration of V.F.As in artery was higher than that of vein exception for portal vein. It is suggested that difference of V.F.As concentration between artery and vein is due to the utilization of V.F.As in tissue or organs which had been perfused by blood flow. Fig. 2. Paperchromatogram of volatile fraction in the contents of alimentary tract in the hens fed a fat free diet and fed a soluble starch diet Ac: Acetic acid P: Propionic acid Bu: Butyric acid M: Mixture of standard acid Li: Contents of alimentary tract of the hens fed a fat free diet L2: Contents of alimentary tract of the hens fed a fat free diet A: Contents of alimentary tract in the hens fed a soluble starch diet B: Contents of alimentary tract in the hens fed a soluble starch diet Table 6. Concentration of V.F.As in blood stream of experimental animals (mg/dl) * H.A. and V. are heart artery and each vein, respectively. 184

6 Metabolism of V.F. As in hens It is also suggested that high concentration of V.F.As in portal vein was dependent on the absorption of V.F.As from each digestive tract. Summary In order to survey a relationship between such a composition of feedstuffs as fat or carbohydrate and fermentation of V.F.As in alimentary tract of hens, an attempt was made to determine an effect of fat free diet or carbohydrate on the amount of V.F.As in digestive tract and serum of egg laying hen. The results are summerized as follows. 1. In the hens fed a fat free diet or carbohydrate, crop sac had a highest average net amount of V.F.As. It was found that high concentration of V.F.As was observed in duodenum and caecum. There was no difference in concentration of V.F.As between hens fed fat free diet and those fed carbohydrate. These facts suggest that fat or carbohydrate did not affect the fermentation of V.F. As in digestive tract or laying hens. 2. In hens of both group, net amount of V.F.As ranged from 7.6 to 9.5 grams. The results seem to suggest that daily productivity of V.F.As in digestive tract of hens is about 8.5 grams as acetic acids. 3. Nature of V.F.As fraction in digestive tract of hens was identified as a spot of acetic and propionic acid, paperchromatographically. 4. A highest concentration of V.F.As was observed in portal vein. It was also detected that the concentration of V.F.As in artery was higher than that recorded in vein. 5. These results should suggest that fermented V.F.As was absorbed from portal vein and that difference of V.F.As concentration between artery and vein is due to the utilization of V.F.As in tissues or organs which had been infused by blood stream. A part of this experiment was reported in the meeting of Tohoku block of Japanese Society of Zootechnical Science at Morioka on August References 1) EDWARD J. CONWAY (1961) Microdiffusion Analysis and Volumetric Error (Translated by Otoharu Ishizaka)., 3 ed Nankodo. Tokyo. 2) Fujii, Y (1961) Method of Biochemistry Quantitative Analysis revised 12 ed Nanzando. Tokyo. 3) Watanabe, E (1965) Medicine and Biology, 70 (5): ) Watanabe, E. and A. Chiba (1968) Jap. J. Zootech. Sci., 39:

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