Emese Andrásofszky

Evaluation of mercury and lead content in the liver of the cormorant (Phalacrocorax carbo sinensis) population of Kis-Balaton, Hungary

Mercury and lead concentrations were measured in the livers of cormorant (Phalacrocorax carbo sinensis), an aquatic bird species living and nesting in the special, highly protected nature conservation area of Kis-Balaton, Hungary. The measurements of metal concentrations were performed by atomic absorption spectrometry using the cold vapour method for mercury and the electrothermal method for lead. Mercury concentrations in the livers were significantly higher in the adult population (4.479 ± 3.336 mg/kg dry matter, DM) than in the juvenile birds (2.682 ± 2.087 mg/kg DM), indicating an increase of bioaccumulation with age. A similar pattern was not observed for lead. There were no statistical differences between males and females either in mercury or in lead concentrations. The average levels of mercury (3.580 ± 2.906 mg/kg DM) and lead (0.746 ± 0.499 mg/kg DM) were statistically different in the liver. No correlation was found between the concentrations of the two heavy metals. Recently, the wild birds have been chronically exposed to subtoxic amounts of metals which have a tendency to accumulate especially in the soft tissues.

Effect of fulvic and humic acids on iron and manganese homeostasis in rats

The objective of this study was to investigate the effects of fulvic acid (FA) and humic acid (HA) as the two main compounds of humic substances, separately on Fe and Mn homeostasis. Seventy-two male Wistar rats were randomly divided into 9 experimental groups. The control diet (AIN-93G formula) and diets supplemented with 0.1%, 0.2%, 0.4% and 0.8% HA or FA were fed for 26 days. Fe and Mn concentrations of the large intestinal content, liver, kidney, femur and hair were determined. No significant differences were observed in the production parameters. The effects of FA and HA on iron homeostasis were significantly different. FA proved to be a good iron source, and slightly increased the iron content of liver and kidney, but - up to a dietary iron level of 52.7 mg/kg - it did not influence the efficiency of iron absorption. Above a dietary iron level of 52.7 mg/kg down-regulation of Fe absorption can be assumed. HA significantly stimulated the iron uptake and there was no down-regulation of Fe absorption up to 0.8% dietary HA supplementation level (61.5 mg Fe/kg diet). In the HA groups the iron content of the liver and kidney decreased significantly, suggesting that in spite of the better Fe absorption, the HA-Fe complex does not provide iron to the investigated organs. Neither FA nor HA supplementation influenced the Fe content of the femur and hair and slightly decreased the Mn concentration in the large intestinal content. This effect was significant (with a 22.7% Mn concentration decrease) only at the HA supplementation rate of 0.8%. Neither FA nor HA influenced significantly the Mn concentrations of the liver, kidney and femur. The Mn concentration of the hair in rats receiving FA- or HA-supplemented diets was higher than in the control rats; however, this result needs further confirmation.

EFFECT OF ARGININE OR GLUTAMINE SUPPLEMENTATION ON PRODUCTION, ORGAN WEIGHTS, INTERFERON GAMMA, INTERLEUKIN 6 AND ANTIBODY TITRE OF BROILERS

The objective of this study was designed to test whether supplementation of the diet with arginine (Arg) or glutamine (Gln) or their combination influences the production, organ weights and humoral immune response of broilers. A total of 432 one-day-old male Ross 308 broiler chickens were divided into 6 treatment groups: control, Arg-0.5%, Arg-1%, Gln-0.5%, Gln-1% and Arg-0.5%+Gln-0.5%. Drinking water and feed were provided ad libitum. On day 18 of the experiment 50% of chickens in each treatment group were immunised with bovine serum albumin. Ten and 21 days after immunisation blood samples were collected to determine the anti-albumin IgY titre, interleukin 6 (IL6) and interferon gamma (IFNG) and to measure the weight of the liver, spleen, bursa of Fabricius and thymus. Arg or Gln supplementation of the diets influenced neither the production nor the organ weights until 18 days of age. Between 18 and 39 days of age both Arg (0.5% and 1%) and Arg + Gln supplementation improved the feed conversion ratio (FCR) by 3.7%, 6.3% and 4.9%, respectively, while Gln-1% worsened it by 15%. Immunisation slightly (-0.79%) depressed the body weight gain of broilers fed the control diet, which was significantly improved by both Arg (0.5 or 1%) and Arg + Gln supplementation. Immunisation increased the weight of the spleen, bursa and thymus and decreased that of the liver. Supplementation with 1% Gln depressed (-5.13%) the body weight gain of the immunised chickens but strongly stimulated the immune response. Supplementations with Arg and Gln did not influence the IL6 and IFNG level of the blood; however, on day 10 after immunisation these two parameters showed a negative correlation with each other. Regarding production, organ weights and immunity, Arg supplementation should be recommended in the grower phase, while Gln supplementation can be useful in pullets raised for egg production, where a good immune response to vaccinations is an important factor.

Pathological changes induced by rancid feed in rats and effects on growth and protein utilisation

The objective of this trial was to study the effect of rancid feeds on the health status and growth of rats and to determine the pathological changes induced by dietary rancidity. Forty-two weaned male rats (body weight: 69.3 +/- 1.0 g) were divided into seven experimental groups (n = 6 each). Rats in the different groups were fed diets containing meat-and-bone meal at an inclusion rate of 19 to 22%, low or high in peroxides and high in organic acids, with or without antioxidant. The diets were isoproteic (10%) and isolipidic (6%). During the 26-day-long trial (5 days for adjustment and 21 days for the main period) the body weight gain and the feed consumption were recorded. At the end of the trial detailed gross and histopathological examinations were performed. Feeding high-peroxide feed mixtures for 21 days significantly (P < 0.05) decreased feed intake and liveweight gain, while high organic acid concentration had only slight negative effects. Antioxidant supplementation alleviated the harmful effects, especially in the high-peroxide group. The ingestion of rancid feed mixtures and the subsequent decreased feed intake caused a decrease of glycogen content in the hepatocytes, accompanied by a slight centrolobular fatty infiltration. Peroxides caused lymphocyte depletion in the spleen, decreased the size of Malpighian bodies and the number of lymphoblasts, and altered the spermatogenesis. The protective effect of the antioxidant mixture seemed to be negligible in this respect.