The growth of Clostridium 16-An and the collagen digestion activity during a mixed culture with aerobes were investigated in respect to the influence of temperature, NaCl concentration and nitrogenous components in the medium as well as the change in redox potential. The results are summarized as follows. 1) i6-An grew vitally at30-40°C, but below 20°C practically grew neither in the single culture of 16-An nor in the mixed culture. 2) During the mixed culture, Eh of the medium decreased gradually to the value of -0. 2 V with the growth of aerobes. This Eh decrease was accompanied by an increase in collagen digestion activity and 16-An count. Con-cerning collagen digestion, the activity of the mixed culture with aerobic 37-1 (Vibrionaceae) was stronger than that with aerobic C-24 (Pseudomonas). 3) The growth of 16-An was pre-vented by addition of NaCl from making 5% concentration in the medium, irrespective of the presence or absence of aerobes. 4) 16-An required a medium containing meat extract for growth and production of collagen digestion ability. However, a supplement of peptone or ge-latin to the medium accelerated the growth of 16-An and strengthened its collagenolytic ability. Particularly in respect to the effect of gelatin, it is notably suggested that a specific effect of ge-latin in the medium of mixed culture with 37-1 is responsible for the additional increase in col-lagen digestion activity in such a way that the effect varies depending on the kind of associat-ed aerobe.

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This study elucidated the reason why the Gerber test gave higher values than RoseGottliebmethod, and proposal was made to reduce the differences between two methods. Gas chromatographic analysis showed commercial isoamyl alcohols contained no contaminant other than activeamyl alcohol(0-41%). Incorporation of active amyl alcohol to isoamyl alcohol gave no effect onthe value. Gas chromatographic analysis of fat obtained by Gerber test revealed that it containednot only triacylglycerol but fatty acids, isoamyl alcohol and their esters which were consideredto cause higher value. Isoamyl alcohol-isobutyl alcohol mixture (7:3, v⁄v)as replacement of isoamyl alcohol reduced values in the Gerber test. The former gave 0.01%higher value than RoseGottlieb method, while the latter 0.05%.

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Data of 1313 beef steers belonging to the Okayama strain of Japanese Black cattle were analyzed to estimate the effect of pedigree structure on carcass traits. A least-squares analysis of variance was carried out. Sire, age in days, inbreeding of steers, the sires and the dams, and genetic contribution of eighteen ancestors to the dams were taken as independent variables; average daily gain from birth, dressing percentage, marbling score and rib-eye area were used as dependent variables for the analysis. The effect of sire was significant only on marbling score in the four dependent variables, though differences between least-squares means of sires were not sufficiently large to consider them as indices for effective selection. Partial regression of age to average daily gain was significant and negative, though it was significant and positive to the other dependent variables. Partial regressions of some ancestors' genetic contributions to the dams on marbling score were statistically significant. This means that the selection of dams by the genetic contribution of the ancestors to the corresponding dams, or a combination of them, namely pedigree structure, will be effective to improve the marbling score of beef steers belonging to the Okayama strain of Japanese Black. This technique could be practiced more efficiently with simultaneous use of the selection of the sire by the breeding value estimated from a pro-geny test. The technique may accelerate, therefore, the improvement of beef performance of Japanese beef cattle. Heritability of marbling score was estimated as 0.529, although the value is probably overestimated because of under estimation of phenotypic variance calculated from sire component and mean square for residue which is already reduced by the regressions of genetic contribution to the dam. The other heritabilities were estimated as very low: selection of sire will not be effective to improve average daily gain, dressing percentage and rib-eye area so far as this kind of data is concerned.

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Ferritin, iron and total-iron binding capacities in blood serum of 20 Holstein steers of varying growth rates and grazing were measured. Sixteen steers averaging 200kg live weight (6-7 months of age) were divided equally in number into four weight gain groups (1.3, 0.8, 0.4 and 0.0kg). They were fed in confinement by four different feeding programs for 135 days. Four steers were grazed in pasture for 135 days, and their daily gain was 0.42kg. Serum ferritin concentration decreased slightly in steers of the 1.3kg daily gain group, but this protein concentration remained at a high level throughout the experimental period in steers of 0.0kg daily gain, although nutritional anemia did not appear. In contrast, serum ferritin concentration in the 0.8kg daily gain group remained constant at 15ng/ml. Serum ferritin concentration increased sharply in grazing steers with aging. On the other hand, total ironbinding capacity was clearly higher in animals of the 1.3kg daily gain group than that of other groups. Also, serum iron, counts of red blood cells, hemoglobin concentration and hematocrit value in cattle of the 1.3kg daily gain group were markedly high compared with those of other confinement groups. In grazing steers, erythrocytes increased in numbers and showed microcytic and normochromic change. Also, ferritin and non-heme iron concentration in the liver and spleen of cattle of the 1.3kg daily gain group were significantly lower than those of other confinement groups. Nonheme iron in the liver of grazing steers increased significantly after grazing. It was suggested that ferritin, iron, total iron-binding capacity and other hematological measurements in the blood of steers each reponded well to high caloric nutritional levels. However, changes in those values in undernutrition in this study were not clear. The elevation of body iron in grazing steers may be caused by a free intake of iron rich soil in pasture.

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The mucosubstance histochemistry of the gastric mucosa in pigs was studied using the Alcian blue (pH 2.5)-periodic acid-Schiff reaction (AB-PAS), high iron diamine-Alcian blue (pH 2.5) staining (HID-AB) and paradoxical concanavalin A staining (PC). The surface epithelial cells of the cardiac gland region contained a large amount of sulfomucins. The mucous neck cells contained either neutral mucins or sialomucins. In the pyloric gland, some cells contained neu-tral mucins and others sulfomucins or sialomucins. On the other hand, the cardiac gland cells, mucous neck cells and pyloric gland cells exhibited class-III reactivity by PC staining. The fact that the gastric mucosa contains a lot of sulfomucins and varied types of mucosubstances may be correlated with the digestive function of pigs, which are omnivorus animals.

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The experiment was conducted to determine if dietary fat modified in vivo glucose metabolism and lipogenesis from glucose in growing chick under the identical energy and protein intake. White Leghorn male chicks (3 weeks of age) were fed a glucose, lard or coconut oil diet, respectively, for 14 days to be isocaloric and isonitrogenous. Glucose metabolism in vivo was monitored after the injection of 2-³H-and U-¹⁴C-glucose. Feeding the lard diet significantly increased body fat as compared with the glucose or coconut oil diet. Glucose replacement rate and glucose body mass were not affected by dietary treatments. The extent of recycling of glucose and expired ¹⁴CO₂ was reduced by feeding the fat diets. Lipogenesis in vivo from glucose in the liver and carcass was depressed in chicks fed the fat diets, especially in chicks fed the lard diet. Glyceride-glycerol synthesis in the liver, however, was not influenced by the dietary treatments. The results suggest that feeding the fat diets, induced the spared glucose utilization, which may be mainly dependent on the reduction of glucose oxidation and recycling, and that the extent of these effects were modified by the type of dietary fat.

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Evaluation techniques for the nutritive values of rice straw, which is a stuff for ruminants, are required for more efficient feeding and for easier use at site. This paper will present a simplified method for evaluating the nutritive values of rice straw from correlations between the nutritive values from in vivo digestion trials under constant feeding conditions with wethers and certain chemical components or in vitro dry matter digestibility of rice straw. 1) The chemical components that could be used for estimating the total digestible nutrients were crude protein, crude fiber, acid detergent fiber, crude silica, and crude silica plus lignin; in the case of digestible energy, only acid detergent fiber among the above mentioned could not be regarded as an estimate of nutritive value, because it just failed to be significant. 2) The components that could be used for estimating the digestible crude protein were crude protein and gross energy. 3) The total digestible nutrients, digestible energy, and digestible crude protein could be estimated by in vitro digestibility, namely the artificial rumen method, quick method or two step enzyme method.

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This study was conducted to investigate the effect of protein and/or calorie malnutrition on bone growth in calves. Ten calves weighing 130-140kg were sed. At the beginning of experiment, 2 calves were killed and the other animals were divided into 4 groups as follows, 1) NN (DCP 12%, TDN 78%), 2) LC (DCP 12%, TDN 60%), 3) LP (DCP 5.5% TDN 78%) and 4) LL (DCP 5.5% TDN 58%). After 12 weeks of this experiment, all calves were killed and the tibia and mandible were collected. The body weight gain was less in LC than in NN and more than in LP and LL. The length and width of both mandible and tibia and the cortical width of the tibia were less in malnourished groups than those in NN. Bone mineral contents and bone density did not change, but bone alkaline and acid phosphatase activities were reduced in malnourished groups. The serum growth hormone (GH) concentration did not change in each group, but the serum total thyroxine concentration decreased in malnourished groups, which might retard bone growth in calves.

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Effect of defaunation on ruminal gas and VFA production was studied by an in vitro incubation technique. Two fistulated ewes were used (one ewe died during defaunation in the second experiment). They received two different diets, all forage (AF) and forage: concentrate= 50: 50 (FC), which promoted different size of protozoal population (3.0 × 105 organisms/ml with AF and 12.6 ×106 organisms/ml with FC). Defaunation decreased acetate and butyrate production, while it increased propionate production. Defaunation decreased also total VFA production. These effects were observed with both diets, but were clearer under the presence of a larger protozoal population promoted by FC diet. Defaunation decreased methane and carbon dioxide production with FC diet, while it had no clear effect on these gas production with AF diet. Consequently protozoa enhance acetate, butyrate, methane and carbon dioxide production and depress propionate production. Defaunation, therefore, may improve energy efficiency of diets, if total VFA production is not greatly depressed. However their quantitative contribution to these end products may depend on their population size.

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