In order to clarify the metabolism of threonine (Thr) in laying hens, the effects of dietary Thr levels on tissue amino acid (AA) concentrations and Thr metabolic enzyme activities; Thr aldolase (Thr to glycine (Gly)), Thr dehydratase (Thr to α-ketobutyric acid), Thr dehydrogenase, serine (Ser) hydroxymethyltransferase, Ser dehydratase, were studied. Laying hens at 38 weeks of age were fed diets with five graded Thr, from deficiency to excess, 0.32 to 0.67%, for 28 days. After then, the concentrations of the three AA, Thr, Ser and Gly, and the enzyme activities of Thr and Ser degradation and Gly formation in homogenates of liver, kidney and duodenum were determined. When the dietary Thr was increased from 0.32 to 0.42%, the concentrations of Thr in the three tissues remained constant, and then increased linearly with increasing dietary Thr levels. The break point of both lines of Thr concentrations which was estimated to be 0.46%, agreed with the requirement determined from the performance and plasma concentration of Thr. The concentrations of Ser remained relatively constant until the dietary Thr was less than the requirement level and then decreased, and those of Gly remained constant in all the dietary Thr levels in the three tissues. However, the concentration of each AA differed significantly among tissues. The activities of all enzymes investigated in the liver were not affected by the changes of dietary Thr levels. In the kidney, only the activity for the formation of Gly from Thr was enhanced by increasing the dietary Thr levels. In the duodenum, all enzyme activities except for Gly to Ser responded to increase of dietary Thr levels. The activities of all enzymes in the duodenum were two or three times higher than those in other tissues. From these results, the increment of conversion from Ser to Gly might be one of the reasons why the tissue Ser concentration decreased when dietary Thr levels were higher than the Thr requirement levels.

View full abstract

The experiment was conducted to investigate the effects of immunostimulation and a probiotic (Bacillus cereus CIP 5832) on immune responses in broiler chickens. Two levels of B. cereus were given tomale chicks; either 0 or 50mg/kg (5×10⁸cfu/kg) during the experimental periods. Chicks were kept at either a dirty or clean environment from one to 22 day of age and thereafter injected intraperitoneally with Escherichia coli lipopolysaccharide (LPS, 500μg/chick) as an immunostimulator 16 hours before the end of the experiment. A dirty environmental condition was achieved by raising multiple cycle of chicks in the batteries, cages, rooms, and by letting droppings, dust and dander accumulation before the start of the experiment. Dirty environmental condition reduced body weight gain and feed intake. Feeding B. cereus improved feed efficiency in chicks raised in the dirty environment, but not the body weight gain and feed intake. The proliferative response of mononuclear cells of spleen obtained from chicks kept at a dirty environment was lower than that from chicks kept at a clean environment. Feeding B. cereus prevented the reduction in the response in chicks raised in a dirty environment. A dirty environmental condition tended to increase the plasma IL-1 like activity in the saline-injected groups, and significantly enhanced the activity in the LPS-injected groups. Dietary B. cereus lowered the increased plasma IL-1 like activity following LPS injection in the chicks kept at dirty environment. The results suggested that sanitary condition affected immune responses, and LPS injection increased the changes in immune responses. Feeding B. cereus CIP 5832 could improve the changes induced by the immunostimulators.

View full abstract

Functional properties of bovine alpha lactalbumin (α-LA) are related to its structure and are governed by changes in conformation of protein molecules. The effects of mechanical agitation, high temperature and pH on the structural changes of α-LA were examined by circular dichroism (CD), differential scanning calorimetry(DSC), spectrofluorometry, spectrophotometry, and electrical conductivity methods. The α-helixcontent decreased signifcandy below pH 5 and above pH10 The transition enthalpy values at pH2, 6.7 and 12 were 91.5, 111.6 and 100.3J/g, respectively. Heating α-L, A from 60 to 100°C at pH6.7, resulted in the increase of absorbance and electrical conductivity and the decrease in fluorescence intensity. Higher speed agitation decreased the α-helix content considerably. It is concluded that α-LA undergoes a conformational change due to strong acid and alkaline pHs, high temperatures and strong agitation.

View full abstract

flatoxins are most potent carcinogens and a powerful mutagen among food-borne mutagens. In the present study, antimutagenic activities of milk cultured with five Lactobacillus strains on the mutagenicities of aflatoxins B1, B2, and G1 were investigated in vitro using Salmonella typhimurium TA 100 as the indicator bacteria. Cultured milk, containing 10% milk solids-not-fat and 0.3% yeast extract, were incubated at 37°C for 24 hours. The milk that was cultured with Lactobacillus sp. LA-2 strain had the highest inhibition (58.6 to 77.4%) against the mutagenicities of all the aflatoxins tested in S. typhimurium TA100 under the standard assay conditions with S-9 mix. Furthermore, the antimutagenicity of the culture with Lactobacillus sp. LA-2 strain was examined at different pH, incubation times, and mutagen doses. This cultured milk showed the highest inhibitory effects against aflatoxins B1, B2, and G1 at pH7.0, and mutagen dosages of 1.0μg/ml, 100μg/ml and 10μg/ml respectively. A 24 hours incubated Lactobacillus sp. LA-2 milk also showed the highest antimutagenicity against aflatoxins B1, B2, and G1.

View full abstract

To evaluate the anoretic effect of Cholecystokinin (CCK) in goats, CCK (sulfated CCK -8) was administered into the third ventricle of the brain either by a bolus injection or continuous infusion in five castrated male goats which were deprived feed for 22 hours. The injection doses of CCK were 400, 1, 600 and 3, 200pmol, and the infusion rates were 50, 200 and 400 pmol/h, respectively. The injections were given just before feeding, whereas the continuous infusions, which lasted for 1 hour, were started 30 minutes before feeding. The injection of CCK resulted in a temporal but drastic decrease in feed intake in the initial 15 min of feeding and led to a decrease in the cumulative feed intake over 2 hours, the extent depending upon the dose. When CCK was administered by continuous infusion, the anoretic effect was more pronounced. Feeding behavior was almost completely suppressed during the infusion period and the decrease in cumulative feed intake was not only dose dependent but also much larger than for a bolus injections. From these results it was concluded that CCK administration into the third ventricle exerts an anoretic effect in conscious goats, dose dependently with much lower doses for continuous infusion causing an effect compared with the bolus injection.

View full abstract

Data from 59 Holstein single calves born from primiparous cows were collected to clarify the effect of age at first calving of dams and calf sex on blood components of calves at 1 day of age. Blood hematocrit and hemoglobin as well as plasma Mg and Zn were higher in female calves than in male calves. Blood hematocrit, hemoglobin and plasma minerals of calves at 1 day of age were not affected by age at first calving. A positive correlation between gestation length of dams and body weight of calves, and negative correlations between gestation length of dams and plasma Zn of calves and between body weight and plasma Zn of calves were observed.

View full abstract

A study was undertaken to determine the metabolizable energy (ME) requirement for Holstein dairy cows carrying single (n=12) or twin (n=6) Japanese black fetuses in late pregnancy. We observed a decrease of ME intake during the last trimester of a twin pregnant cattle. During this time, cows with single fetus gained weight (weight on pregnancy minus weight of the conceptus), while dams with twins lost weight. At near term ME intake decreased and heat production was increased by growing gravid uterus. Therefore, negative energy balance was observed especially in twin pregnant cattle. There were no differences in efficiency of energy utilization for fetal growth between single (11.6%) and twin (13.1%). ME requirements for the last 2 months of gestation of dairy cows are 265Meal with single Japanese black fetus and 450Meal with twin Japanese black fetuses. Additional ME for pregnancy are shown to be 4.4Mcal/day with single Japanese black fetus and 7.5Mcal/day with twin Japanese black fetuses during the last 2 months before parturition.

View full abstract

The present in vivo study investigated whether beef intake can reduce fatigue of mice by examining exercise load. There was no difference in body weight of all mice in the experimental groups for 5 weeks. There were also no significant differences in the changes of dietary intake among the groups either. The long-term intake of beef and/or beef tallow did not negatively influence mice with regard to appearance, transition of body weight and food intake. The swimming time of mice fed Beef+Beef tallow (BT) was significantly prolonged (p<0.05). That of mice fed Casein+BT tended to be prolonged, but was not significantly different from that of the control (fed Casein+soybean oil (SO)). The hanging time in 3min after forced swimming in mice fed Beef+BT and Casein+BT was significantly prolonged (p<0.05). In 30min after forced swimming, only mice fed Beef+BT showed a significantly prolonged hanging time compared to that of controls (p<0.05). These results suggested that beef, especially lean meat may have an anti-fatigue effect. The glucose and L-lactic acid levels in plasma of mice fed the casein diet remarkably reduced compared to the levels prior to exercise. In the Beef+BT-fed mice, the preexercise glucose level equalled and the pre-exercise and L-lactic acid level was slightly increased compared to the post-exercise levels. The changes in these parameters in the Beef+BT-fed group were less than those in the control group.

View full abstract

Feather and waste wool are composed of keratin protein, therefore they are valuable protein resources. However, there is no simple and large scale solubilization procedure for production of animal feed and organic fertilizer from feather and waste wool. As a result of our investigation, feather and wool were found to be solubilized by alkaline solution under room-temperature and normal atmospheric pressure conditions. Ninety two% and 96% of feather and wool were, respectively, soiubilized by 5% sodium hydroxide treatment at 30°C for 20h. Both the feathersoluble and the wool-soluble contained about 1% L-serine, about 0.5% glycine as free amino acids and very small amount of unknown amino acid derivatives. Amounts of the unknown derivatives were increased 5 to 10 times by the treatment for 68h. The materials in the solubles were fractionated to a precipitate fraction and a supernatant fraction at 90% ethanol concentrtion. In the case of feather, the same amounts were equally divided into both fractions. In the case of wool, 77% and 23% of the solid were divided into the precipitate fraction and the supernatant fraction, respectively. From these results, feather and wool were found to be largely degraded to low molecular weight materials. Aside from the generally well-known amino acids such as Lglutamic acid, L-cysteic acid, lanthionine and 2 kinds of unidentified amino acid derivatives were also found in the hydrolyzates of both the solubles completely hydrolyzed by hydrochloric acid. No other materials except for amino acids were recognized by thin layer chromatography using 4 kinds of solvents. Large amounts of hydrophobic amino acids such as L-valine and L-leucine were found in the hydrolyzate after the additional enzyme treatment. The feather-soluble and the wool-soluble neutralized by phosphoric acid after alkaline soluhilization could be applicable as a fertilizer.

View full abstract