[Transitory cell antigens of rat liver. II. Effect of synthesis inhibitors of fetospecific serum proteins in normal young animals and after acute hepatic injury]

Metagenomic Insights Into the Effects of Rare-Earth Elements Supplementation on Rumen Digestibility and Meat Quality of Beef Cattle

Rare-earth elements (REE), supplemented as feed additives, effectively improved feed conversion and production performances of monogastrics. However, very little information exists on how REE supplementation affects ruminants. In the present study, twenty-four 18-month-old Jinjiang bull cattle, with initial body weight (BW) of 374.75 ± 14.02 kg, were randomly allotted into four dietary treatments with a 15-day-long preliminary trial: a control treatment (basal diet), a 400 mg/kg REE treatment (basal diet supplemented with 400 mg REE/kg DMI), an 800 mg/kg REE treatment (basal diet supplemented with 800 mg REE/kg DMI), and a 1,200 mg/kg REE treatment (basal diet supplemented with 1,200 mg REE/kg DMI). Based on the results, the optimum supplementation scale was chosen for a 60-day-long follow-up feeding procedure. At the end of the feeding period, all bull cattle were slaughtered. Feed intake, average daily weight gain, carcass performances, meat quality, and rumen microbiota were measured. Results indicate a positive response in terms of growth performance and gastrointestinal digestibility to REE supplementation, and 400 mg/kg DMI treatment presented the most average daily feed intake (ADFI), the best average daily weight gain (ADG), and the least F/G. REE also significantly decreased the ruminal propionate content compared with control treatment. As to microbiota, despite no increases in bacterial community abundance, there was a proliferation of Bacteroidetes and Tenericutes and suppression of Actinobacteria under REE treatment. Furthermore, REE treatment significantly increased the meat protein content and decreased meat fat content. There was also an increase in the activities of the enzymes related to lipid syntheses. Fatty acid synthetase (FAS) and malate dehydrogenase (MDH) were significantly suppressed, while the activity of the lipolysis-related enzyme, lipoproteinesterase (LPL), was enhanced. In summary, REE supplementation provided an effective regulation on ruminal microbiota, facilitation of ruminal fiber digestibility, promotion of feed conversion, suppression of lipid deposition, and finally, improved the production and meat quality of beef cattle.

Purification of mouse alpha1-fetoprotein and preparation of specific peroxidase conjugates for its cellular localization

Mouse alpha1-fetoprotein (AFP) was isolated from amniotic fluid by immunoadsorbent columns and preparative electrophoresis. Specific antibodies were isolated from monospecific hyperimmunsera by use of immunoadsorbents, and subsequently coupled with horseradish peroxidase. At the light microscopical level, purified antibody-peroxidase conjugates were used for the cellular localization of AFP in fetal liver by direct and indirect staining methods. Fixatives containing ethanol or aldehydes were tried for antigen staining. Prior to immunocytological reactions, endogenous peroxidases were inhibited by hydrogen peroxide.

[Carcinofetal antigens. I. alpha-fetoprotein (author's transl)]

Alpha-fetoprotein (AFP) is an alpha1-glycoprotein (M.W. about 65000) appearing in the fetal serum of most mammals including man during the early stages of pregnancy; 4 weeks after birth it disappears altogether or exists at very low concentrations as in the normal adult. AFP is formed in the yolk sac, the fetal liver and the gastro-intestinal tract. One of its physiological functions in fetal life is supposed to be the protection of the fetus from maternal oestrogens (oestrophilic property). The clinical significance of AFP is based on the regular and increasing production in primary liver cell carcinoma, less frequently in teratogenetic tumors where it serves as a control of therapy and course of the disease. Less frequent, minor and temporary increases in the AFP serum level occur in several primary tumors with secondary liver involvement, and in inflammatory gastro-intestinal diseases, e.g. of the liver (hepatitis, cirrhosis). AFP has an increasing importance in gynecology (gestational age, fetal distress syndrom, malformations, hydatidiform mole/chorion carcinoma). The physico-chemical properties of AFP are widely known. Both fetal and tumor AFP appear to be immunologically and biochemically identical, as are that of tissue and biological fluids. The differences observed (variants, microheterogeneity) depend mainly on the different content of sialic acid. An antigenetic relationship exists, between the AFP of most species. The immunodiffusion (Ouchterlony) is the most frequently used but relatively insensitive test (1-5 mug/ml) in finding AFP, whereas the radioimmunoassay is the most sensitive one (up to 0,25 ng/ml) and permits the determination of normal serum levels in adults (below 20 ng/ml). The serum concentration in healthy pregnant women lies up to 500 ng/ml, in patients with hepatitis, liver cirrhosis and other liver diseases mostly under 3 mug/ml, whereas in those with primary liver cell carcinoma levels up to and above 600 mg-percent have been found.