Effect of niacin supplementation on the concentration of niacin in rumen and duodenal digesta and in whole blood of sheep.

1. Niacin concentrations in rumen liquor, duodenal digesta and blood, and daily duodenal flow of niacin were measured in four wethers which were fed an oatstraw grain concentrate diet (with normal niacin content) or an oatstraw maize diet (with low niacin content). The effect of an intraruminal supplementation of 2 mmoles nicotinic acid (NIA) or nicotinamide (NAM) on concentrations of NIA and NAM in gastrointestinal contents and blood and on daily duodenal flow of NIA and NAM was studied. The animals were equipped with rumen fistula and duodenal re-entrant cannulae. 2. NIA concentration in strained rumen liquor was 384 and 264 nmol/ml and daily duodenal flow of niacin was 616 and 528 mumoles/d in animals fed normal or low niacin diet, respectively. Intraruminal administrations of 2 mmoles of NIA or NAM raised NIA concentration in strained rumen liquor for approximately 6 h. About 20% of the administered dose of NIA or NAM passed out of the rumen and resulted in a 41% increase in daily duodenal flow of niacin. The remaining 80% of the administered dose of NIA or NAM disappeared from rumen liquor without being washed out. 3. Supplemented NAM was rapidly hydrolyzed to NIA and ammonia when administered into the rumen. 4. NAM concentration in blood appeared to be unaffected by the dietary content of NIA or by niacin supplementation. 5. The NIA concentration in strained rumen liquor was positively related with niacin content of the diet. Increases in duodenal flow of niacin had no marked effect on concentration of NAM in blood. It appeared that feeding diets with different NIA content affected apparent niacin synthesis in the rumen.

Experimental infections in chickens with Chilomastix gallinarum, Tetratrichomonas gallinarum, and Tritrichomonas eberthi.

Flagellates from the caeca of a diseased hen and a diseased goose were transmitted to 35 specific pathogen-free (SPF) chickens. The flagellates of chicken origin were identified as Chilomastix gallinarum, Tritrichomonas eberthi, and Tetratrichomonas gallinarum. T. eberthi was not detected in the material of goose origin. Morphologic studies did not reveal any differences between Chilomastix and Tetratrichomonas specimens from chicken or goose origin. The species from the goose were identified as C. gallinarum and T. gallinarum (Syn. T. anseris Hegner, 1929). Both trichomonad species produced pseudocysts that developed in the faeces of chickens within 3 h after excretion. Only 17% of the trichomonads excreted had reached the pseudocyst stage. All three flagellate species are infective to chickens when inoculated per rectum or per os or when consumed with chlorinated tap water. The prepatency period was always less than 24 h. SPF chickens between 2 and 30 days of age were equally susceptible. The infections persisted at a high level of intensity throughout the observation periods, i.e. up to 7 months. Of 35 inoculated SPF chickens, 2 developed disease (emaciation, ruffled feathers, diarrhoea, dilatation of the caeca). The three flagellate species were cultivated in Diamond's medium for 110 days. Cryopreserved and cultivated flagellates retained their infectivity to chickens.

[Effect of nicotine in pigs (author's transl)]. / Die Wirkung von Nikotin beim Schwein

18 pigs in which venous catheters were positioned for long-term use were injected with nicotine in physiological saline: group 1: 1 mg without anaesthesia; group 2: 1 mg/animal, Hypnodil-anaesthesia; group 3: 0.0143 mg/kg body weight, Hypnodil-anaesthesia. The dose of 1 mg is corresponding to that amount of nicotine contained in the main smoke of a commercially used cigarette. The dose of 0.143 mg/kg body weight is calculated per 1 kg body weight assuming that a man of 70 kg body weight resorbes the total amount of nicotine (1 mg) after maximum inhalation. Application of 1 mg induced the following alterations: sino-auricular block, AV-block of first and second degree, asystolia up to 2 seconds, short decrease in blood pressure and bradycardia as well as flattening and/or inversion and biphasic reaction of T. A longer lasting increase in blood pressure was observed in non-anaesthesized animals. Animals treated with 0.0143 mg/kg body weight showed AV-block of first degree with subsequent extrasystoles. Blood pressure, heart rate and T-wave showed no alterations. Decisive for the induction and extent of acute disturbances seems to be the dose of nicotine. Therefore, a decrease of the nicotine content seems to be indicated toward a "less harmful cigarette".

Effect of high doses of nicotine in pigs. I. Changes of the electrocardiogram.

Pigs in which venous catheters were positioned for long-term use were injected i.v. with high doses of nicotine in physiol. saline. The LD50 was 2.656 mg/kg body weight. Clinical symptoms were mainly: forced respiration, muscular tremor to tetanoid spasms, cyanosis of the skin, salivation and sometimes vomiting. The degree and duration of symptoms were dose-dependent. Ecg changes in anaesthesized pigs following intravenous nicotine injections of 0.126 mg/kg and 0.378 mg/kg at 15 minutes' interval were immediately commencing disturbances of the heart rate in form of bradycardia and asystolia. After 5 sec we observed extrasystoles, tachycardia, sino-auricular block and AV-block of first and second degree as well as a number of T- and P-changes. Changes of the ecg were observed generally for 10 to 15 min, however, the T-wave remained sometimes negative or biphasic-preterminal negative for some hours.