Leptin, GH, PRL, insulin and metabolic parameters throughout the dry period and lactation in dairy cows.

Leptin may play a role in the endocrine-metabolic processes that guarantee the physiological course of lactation in dairy cattle. This study was aimed at determining the changes in plasma concentrations of leptin and some of the main hormones and metabolites involved in the lactogenetic process in high-yielding dairy cows throughout lactation; we also wanted to assess whether leptin secretion is subjected to seasonal influences. Blood samples were collected from 23 Italian Friesian dairy cows from the end of a lactation to the ninth month of the subsequent one; in addition, blood was sampled from 47 dairy cows in different phases of lactation during February and July. Plasma concentrations of leptin, growth hormone (GH), insulin, prolactin (PRL), glucose, non-esterified fatty acids (NEFA) and urea were quantified by either validated radioimmunoassay (RIA) or enzymatic colorimetric methods. At the beginning of lactation, GH concentrations significantly increased, while a significant reduction occurred in leptin and insulin. This endocrine condition, such as the significant increase in NEFA plasma concentrations, is indicative of a marked lipid mobilization. In the more advanced stages of lactation, when both energy and protein balances become positive, leptin plasma concentrations increased, whereas GH and NEFA concentrations declined. During the summer months, a significant increase in leptin plasma concentrations, irrespective of the phase of lactation, was observed. Collectively, our findings suggest that, in dairy cows, leptin may represent a 'metabolic signal' of animal's status of fattening and nutritional level; in addition, leptin seems to be influenced by photoperiod and environmental temperature.

5'-deiodinase activity and circulating thyronines in lactating cows.

To investigate the correlation between lactation and thyroid hormone metabolism, the authors studied concentrations of total and free thyroxine (T4 and fT4), triiodothyronine (T3 and fT3), and reverse triiodothyronine (rT3) in plasma and milk, as well as liver and mammary gland 5'-deiodinase (5'D) activity in dry, early, middle, and late lactating dairy cows. Cows in early lactation show lower plasma levels of T4 and rT3 than dry, middle, and late lactating animals, whereas T3 shows the lowest plasma levels in the dry period; free T4 and T3 show a similar pattern. In early lactation there is a clear decrease in liver 5'D associated with a notable increase in mammary 5'D. Concentrations of T4 and T3 in milk drop significantly in the first few days after delivery, whereas rT3 increases up to the fourth month. The findings suggest a relationship between the hypothyroid status of lactating cows and the rearrangement of organ-specific 5'-deiodinase activity related to the maintenance of the udder's function.

Seasonal variation in the reproductive hormones of male goats.

The aim of this work was to study the circannual plasma profiles of LH, PRL, testosterone (T) and estrone sulfate (E1S) in different periods of the year and to characterize the possible variations in LH and PRL release patterns. We also tried to verify a possible relationship between plasma PRL fluctuations and ambient temperature, as well as the influence of an acute stress condition on levels of plasma PRL. Six adult male goats of the Ionica and Alpine breed reared in Southern Italy (40 degrees N lat.) were subjected to frequent samplings (every 15 min for 6 h) once a month for a whole year. The blood samples were assayed for plasma concentrations of E1S, LH and PRL by radioimmunoassay, and for T by enzymeimmunoassay. The ambient temperature was recorded on each day of bleeding. Sex steroids and PRL showed marked circannual variations, with the highest levels during the summer (July) and the lowest during the winter-early spring (March). The concentrations of plasma LH did not indicate significant seasonal variations. A positive relationship was observed between plasma levels of PRL and E1S and ambient temperature. The patterns of LH release seemed to change depending on season, but this was not an obvious and common feature in all bucks. The hormone concentrations for plasma PRL profiles seemed to be influenced by an acute stress condition (associated with cannula insertion and handling procedures), with the variations more marked when the plasma levels of PRL were low.

Listeria SPP. and enteric pathogens in raw meat: a survey in the Ferrara area.

The Authors report the results of a study performed on 113 samples of raw meat of 6 different animal species in order to evaluate the extent of contamination by some organisms responsible for food-borne infections. A total of 2 strains of Salmonella (1.7%), 36 of Yersinia (31.8%), 35 of Campylobacter (30.9%) and 13 of Listeria (11.5%) were isolated. The possible role of contaminated meat in cases of human listeriosis is pointed out.

Dead fecal yeasts and chronic diarrhea.

The authors report 20 patients in whom a large number of dead or severely damaged yeast cells, supposedly Candida albicans yeasts, were the possible cause of chronic recurrent diarrhea and abdominal cramps. It is suggested that the presence of large numbers of these microorganisms in stools may be considered among the possible etiologies of diarrhea in the 'irritable bowel syndrome'. The possible source of these yeast-like cells, the causes of cell damage, and the mechanisms by which these organisms may induce diarrhea should be investigated.

Evaluation of a commercial selective enrichment broth for campylobacters.

A commercial selective enrichment broth for campylobacters has been tested with 580 human and 120 animal fecal specimens, by comparing its performance with that of direct plating of duplicate specimens. No appreciable advantage was noted in isolations of C. jejuni from human stools (22 versus 21), while a statistically significant (p less than 0.001) superiority was found in isolations from animal specimens (53 versus 30). The combined procedure (i.e. direct plating plus enrichment) allowed a total of 27 isolations (4.7%) from human specimens and 57 isolations (47.5%) from animal specimens.

Detection of oestrogen residues in meat by radioreceotor assay.

A radioreceptor assay, suitable for detecting residues in the meat of any compound with oestrogenic activity, is described. The assay is based upon the use of a purified preparation of oestrogen receptors obtained by affinity chromatography from swine uteri. The method was validated by measuring the oestrogenic activities in plasma and meat of diethylstilboestrol or oestradiol treated calves. The standard curve was performed by using oestradiol. Plasma levels of oestrogenic activity, expressed as equivalent of oestradiol, rose above control values 2 days after both diethylstilboestrol and oestradiol treatments, then declined to basal values by day 6 after the treatments. The levels of oestrogenic activity 10 days after treatment, found in the meat of diethylstilboestrol treated animals, were significantly higher than those found in control animals. No differences were found, however, between meat samples of control and oestradiol treated animals.

Physiological levels of androstenedione and testosterone in some edible tissues from calves, bulls and heifers.

The physiological levels of androstenedione and testosterone in muscle, kidney and fat of calves, bulls and heifers were determined by RIA. The androstenedione showed the highest levels in fat and the lowest in muscle tissues. Testosterone showed the same distribution only in male animals, whereas in females the highest levels were in kidney. In fat tissue androstenedione was constantly higher than testosterone in all examined animals. In muscle tissue androstenedione levels were higher than those of testosterone in all female animals and in male calves, whereas testosterone was higher in bulls. Testosterone was the main androgen in kidney tissue in both young and adult animals, irrespective of sex.

Androstenedione and testosterone concentrations in plasma and milk of the cow throughout pregnancy.

Androstenedione concentrations in both plasma and milk were higher than those of testosterone throughout pregnancy. Testosterone concentration increased during pregnancy; the levels in milk were always lower than in plasma. Androstenedione concentrations increased in plasma and milk during pregnancy but the values were twice as high in milk as in plasma after Day 90. This change in androstenedione distribution suggests that the mammary gland could be active in the uptake of androstenedione from plasma to milk or that the mammary gland itself might synthesize this hormone.

Concentrations of progesterone, 17 alpha-hydroxyprogesterone and 20 alpha-dihydroprogesterone in the plasma of mares during pregnancy and at parturition.

Plasma concentrations of progesterone and 17 alpha-hydroxyprogesterone were high in the 2nd and 3rd months of gestation, but 20 alpha-dihydroprogesterone increased from a level of 2 ng/ml, during the first 3 months, to 10-15 ng/ml during months 5-10, to reach 80-120 ng/ml during the last 30 days before foaling.

Prostaglandin F-2 alpha and LH release in immature ewes.

The effect of PGF-2 alpha on LH release in immature ewes was studied. One intramuscular injeciton of PGF-2 alpha induced LH release 36-72 h after treatment in 3/4 ewes. The LH variations were not associated with changes in the plasma concentration of progesterone and oestrogens. These results suggest that the LH release in immature ewes is due to PGF-2 alpha acting at central structures.

[Isolation of Yersinia enterocolitica from drinking water and human feces]. / Primi isolamenti di Yersinia enterocolitica da acque superficiali e da feci umane.

Twelve strains of Yersinia enterocolitica (46.15%) were isolated from 26 water samples of the Po river (1.3-1.5 1), 3 strains (16.67%) were isolated from 18 water samples of the Reno river (500 ml) and 1 strain (2%) was isolated from 50 fecal specimens of healthy adult subjects. It is suggested that further studies are needed in order to determine the occurrence of Yersinia enterocolitica in Italy.