Influence of the gut microbiota on blood acute-phase proteins.

Little is known about the bovine intestinal microbiota influence on systemic innate immune responses. The objective of the present study was to determine relationships between acute-phase proteins in blood serum of cows [C-reactive protein (CRP), LPS-binding protein (LBP) and haptoglobin (Hp)] and the faecal microbiota. Fifty-two healthy cows (2-8 years old) were investigated. Faecal bacteria were determent characterized by in situ hybridization with 16S/23S rRNA-targeted probes and by conventional culture methods. The population of Gram-negative faecal bacteria (Enterobacteriaceae) was correlated negatively with CRP and positively with LBP in blood plasma, independent of the method used. Similar results were observed with Clostridium perfringens. No correlation was found between the faecal population of intestinal bacteria and Hp levels in blood plasma. This datum indicates that intestinal bacteria, especially Enterobacteriaceae and C. perfringens, may influence the level of CRP and LBP in blood plasma. These findings can be very important for diagnostic evaluations of the intestinal microbiota and provide specific information about its regulation.

C-reactive protein and antibacterial activity in blood plasma of colostrum-fed calves and the effect of lactulose.

Several milk proteins are very important for immunological defense and can be absorbed in the intestine of calves in the first hours after birth. The influence of colostrum intake and the effect of additional lactulose application on the concentration of C-reactive protein (CRP) in blood were investigated. The CRP is known as a mediator of innate immunity. Results were compared to the bovine acute phase protein haptoglobin, and to lactalbumin, lactoferrin, and immunoglobulins in plasma from calves. After colostrum intake, the concentration of most proteins were strongly increased. The data show, for the first time, a significant increase of CRP in the blood of calves 1 d after colostrum intake (nonlactulose group, n = 10), and an even more significant increase in CRP concentration (1 d postpartum) was measured in the group of animals with additional application of lactulose (lactulose group, n = 10) when compared to the nonlactulose group. In an in vitro assay with the plasma of these animals, an increased bactericidal activity was detected against Morganella morganii (1 d postpartum) in both groups, but again a higher activity occurred in the lactulose group. The results of these investigations emphasize the importance of colostrum intake during the first hours after birth for the defense potential of newborn calves. In addition, lactulose may have a positive effect in the period of passive transfer of colostrum proteins and in the immune defense.

Jerusalem artichokes stimulate growth of broiler chickens and protect them against endotoxins and potential cecal pathogens.

Control of intestinal pathogens during the earliest phases of broiler production may be the best strategy for the reduction of human pathogens on processed broiler carcasses. The recent ban on antibiotics in poultry feed has served to focus much attention on alternative methods of controlling the gastrointestinal microflora. A field trial was conducted to evaluate the effect of the fructan-rich Jerusalem artichoke, or topinambur (administered as 0.5% topinambur syrup in drinking water), on cultural numbers of selected cecal bacteria (total aerobes, Enterobacteriaceae, Bdellovibrio spp., and Clostridium perfringens) and levels of bacterial endotoxins as well as on body weights and relative weights of organs (the pancreas and the bursa of Fabricius) of chickens in the first 35 days of life (with weekly investigations being conducted). One-day-old broiler chickens (Ross 308) were randomly assigned to experimental (with topinambur) and control (without topinambur) groups. They were allowed free access to a standard broiler diet without growth-promoting antibiotics. Topinambur treatment resulted in a significant increase (P < 0.01) in cecal counts of B. bacteriovorus, which parasitizes susceptible gram-negative pathogens. Topinambur led to significantly smaller numbers of total aerobes, Enterobacteriaceae, and C. perfringens as well as to reduced levels of endotoxins in the blood compared with those for control birds. Increased body weights resulting from topinambur consumption were observed on day 35 of the trial period (P < 0.05). The relative weights of the pancreas and the bursa of Fabricius, however, were higher (P < 0.05) for topinambur-treated broilers than for control birds at the ages of 14, 21, 28, and 35 days. These results indicate that a small amount of topinambur in broilers' drinking water has a beneficial effect on growth performance, reduces bacterial endotoxin levels, and suppresses potential pathogens in broilers' ceca.

Effects of lactulose on the intestinal microflora of periparturient sows and their piglets.

The periparturient period of animals (and humans) is very stressful and influenced by the microecosystem of the gastrointestinal tract (GIT). Performance and productivity of animal husbandry depend on the health of animal mothers and their offspring. We investigated the influence of prebiotic amounts of lactulose in sows and their piglets. Two experimental trial sows received daily 30 ml lactulose, 71 field trial sows received daily 45 ml lactulose during their periparturient period (10 days before until 10 days after parturison). The weaners of trial sows received 15 ml lactulose per 1 kg baby food 10 days before and 10 days after weaning.The effect of lactulose was recorded by performance parameters like number of piglet born alive, losses until weaning, body mass of piglets, daily weight gain of weaners until 35 days after weaning. The effect of lactulose on GIT microflora was estimated by bacterial counts of faeces of sows (total aerobic bacteria, Gram-negative bacteria, Clostridium (C.) perfringens). In order to show a previously unknown effect of lactulose we investigated the levels of antibodies to phospholipase C (PLC) of C. perfringens in plasma of experimental sows and in colostral and ripe milk of field sows. Lactulose influenced the performance parameters of sows in a non-significant way. In case of weaners we recorded significant daily weight gains. Lactulose significantly influenced total aerobic bacterial counts, C. perfringens counts in faeces of sows 20 days after parturison. Under experimental conditions it was shown that trial sows and their piglets had higher IgG-antibody levels to C. perfringens PLCs than the control animals. Similar results were found under field conditions. Trial sows had significant higher IgG-anti LPS (J5) antibodies in milk 10 days after birth.

A novel acute phase marker in cattle: lipopolysaccharide binding protein (LBP).

The host response to infection, the "acute phase response" is a highly conserved series of physiological reactions including marked changes in concentrations of plasma proteins. These proteins have been shown to participate in the immune response to infections. Several recent studies have elevated the role of acute phase proteins (APPs) as predictive markers in infection. APPs such as serum amyloid A and haptoglobin but not C-reactive protein (CRP) have been identified as markers of inflammation in cattle. In humans, lipopolysaccharide (LPS) binding protein (LBP) has certain biological functions in host defence and participates in acute phase reactions. We measured plasma levels of LBP in a group of 20 calves experimentally infected with Gram-negative Mannheimia haemolytica (Pasteurella) in comparison to haptoglobin, the most widely studied APP in cattle. In infected calves, LBP levels rose significantly 6 h after infection, reaching a maximum at 24 h. Haptoglobin concentrations significantly rose after 12 h, and peak responses were measured 48 h after infection. Thus, LBP may prove to be a diagnostic marker in cattle infection and is faster than haptoglobin in detecting sepsis.