Effects of high iron and sulfate ion concentrations on dry matter digestion and volatile fatty acid production by ruminal microorganisms.

The inhibitory effects of iron- and sulfate-containing compounds on the in vitro digestion of a balanced forage diet by mixed populations of ruminal microorganisms were examined in batch cultures. Compounds containing ferrous and ferric cations consistently inhibited DM digestion by up to 36% when added Fe concentrations in cultures were between 100 and 1,000 mg/L. Increased sulfate concentrations of up to 200 mg/L or chloride concentrations of up to 635 mg/L were not associated with decreased DM digestion. Ammonium sulfate additions that provided 200 mg/L of added sulfur increased (P less than .05) digestibility by 10%. Sulfate-containing iron salts tended to be less inhibitory than chloride salts and were associated with increased gas production during digestion. Ferric chloride inhibited (P less than .05) microbial activities at lower concentrations than ferrous chloride. Data suggest that excessive iron supplementation or contamination of feeds with iron-containing pollutants may decrease microbial activities in the rumen.

Catecholamine excretion rates in relation to life-styles in the male population of Otmoor, Oxfordshire.

The paper gives the results of the number of analyses of aspects of life-style and dietary patterns of members of the Otmoor population, in relation to their catecholamine excretion rates. The data reported here are restricted to males. Feelings of boredom were associated with low adrenaline excretion rates. Reported physical tiredness was associated with low adrenaline levels, while mental tiredness seems to be related to high adrenaline levels. People who regarded themselves as having a competitive personality, as being faced by a large number of life challenges, as having to meet self-set deadlines, as choosing to focus on more than one task at the same time, or as being under time pressure had high rates. Cigarette smoking and coffee consumption were related to high adrenaline excretion rates. Taken together these variables can explain 16-20% of variance in adrenaline excretion. Smoking and coffee consumption are of primary importance. The results of similar analyses of noradrenaline are reported.

Associations between polymorphic variety and anthropometric and biochemical variation in two New Guinea populations.

During International Biological Programme studies in Papua New Guinea, on Karkar Island and at Lufa in the Eastern Highlands, information on anthropometric, biochemical and genetic characteristics was collected from the same individuals. Use has been made of this special situation to investigate whether any associations exist between genetic markers and anthropometric and biochemical variation. Those found, and which satisfy criteria established to help in distinguishing real from chance associations, include: P with haemoglobin concentration and serum albumin and cholesterol levels; acid phosphatase with serum albumin level and haemoglobin concentration; anhaptoglobinaemia and serum globulin level; haemoglobin J-Tongariki with serum phosphorus level. The associations are discussed in terms of their arising from the direct result of environmental factors modifying gene expression, chance concordance of environmental and genetic variation, or pleiotropy.