Changes in performance, blood parameters, humoral and cellular immune responses in weanling piglets exposed to low doses of aflatoxin.

A feeding trial was conducted to evaluate the effect of aflatoxin (AF)-contaminated diets on growth and hematological and immunological parameters. Low doses of aflatoxins (140 and 280 ppb) were included in a corn-soybean diet provided for ad libitum consumption to 36 weanling piglets for a period of 4 wk. A "dose-related" decrease in weight gain was observed in treated animals. This effect was significant (P < 0.05) in the 280 ppb-treated group compared to the control group. Ingestion of AF-contaminated feed at either level had no effect on total red blood cell numbers or on their relative number of lymphocytes, monocytes, neutrophils, basophils, and eosinophils in blood. Likewise, AF did not alter globulin, albumins, or total protein concentrations in serum, nor did AF alter the expression of regulatory cytokines produced by either Th1 (IL-2) or Th2 (IL-4) lymphocyte subsets in phytohemagglutinin-stimulated blood samples. By contrast, AF had a biphasic effect on total white blood cell number; the low dose of AF (140 ppb) decreased the total number of white blood cells, whereas the high dose (280 ppb) had the opposite effect. Consumption of AF also increased the concentration of gamma-globulin in the serum. A reduced immune response induced by Mycoplasma agalactiae in the 280-ppb-treated group was also observed. Cytokine mRNA expression in phytohemagglutinin-stimulated blood cells indicated that AF decreased proinflammatory (IL-1beta, TNF-alpha) and increased anti-inflammatory (IL-10) cytokine mRNA expression. These results demonstrate that low doses of AF depress growth and alter many aspects of humoral and cellular immunity in pigs.

The pattern of nutrient and energy utilization, retention and the chemical composition of the body in broilers from hatching to maturity.

The change of the body composition, of the energy content, and of the energy and protein balances was studied in male and female broiler chicks from hatching to maturity (about 140 days). The animals received corn, soybean meal and fish meal based diets which ensured maximal growth. Correlation were established between the ingested feed and the body evolution both from the point of view of quantity and quality, determining the content of protein, fat, ash, water and energy. By experiments of digestibility and by comparative slaughterings the energy and protein requirements both for maintenance and for protein and fat synthesis were determined.

Study on the energy and protein requirements in goats.

The present study focussed on the energy and protein metabolism in pregnant and lactating goats, including young female goats up to 8 months of age, in order to determine feed availability, as also the energy and protein requirements. It was found that the diets consisting of alfalfa hay, oats hay, maize, wheat bran and mixed feeds (fed to suckling females) had different availabilities in terms of energy and protein, according to animal physiological condition and age. Thus, in pregnant goats, 21% of the metabolizable energy (ME) was used as net energy for pregnancy (foetus plus foetal membranes); the amount of energy required for maintenance was 0.400 MJ/kg 0.75. The availability of digestible protein in the intestines (PDI) for pregnancy was 41.2 +/- 3.1%, while the amount of protein required for maintenance was 2.32 g PDI/kg 0.75. In lactating goats 60.7% of the ME of the diets is used as milk net energy, and 58.9 of the PDI as milk protein. Young female goats had a daily net gain ranging between 173 g and 60 g; the amount of protein in the gain varied between 23 g (month 2) and 12 g (month 8); and that of fat, between 8 g (month 1) and 24 g (month 6). The energy and protein requirements for maintenance were found to be 0.450 MJ ME/kg 0.75 and 2.43 g PDI/kg 0.75, respectively. The net efficiency of ME for growth was of 46.2 +/- 3% and of PDI for protein retention, of 50.1 +/- 2%.