Zum Einfluß von Fumarsäure, Salzsäure, Natriumformiat, Tylosin und Toyocerin auf den Säure-Basen-Haushalt

Effect of a microencapsulated feed additive of lactic and formic acid on the prevalence of Salmonella in pigs arriving at the abattoir

The main objective of this work was to investigate the potential of a microencapsulated mixture of organic acids (formic and lactic acid) added to the feed of fattening pigs to reduce the prevalence and shedding of Salmonella when arriving to the abattoir. Two trials were performed. In Trial 1, 24 fattening pigs received one of three diets: a control diet, the same diet including lactic and formic acid (0.4% each) (non-protected blend; NPB), or a lipid microencapsulated blend (0.14% each acid) (protected blend; PB). After 10 days, digesta samples from various parts of gastrointestinal tract were taken. No changes were detected either in pH, total short chain fatty acids (SCFA), lactic/formic acid concentrations in any of the sections studied or in caecal lactic acid bacteria or enterobacteria. In Trial 2, 261 pigs from a commercial farm were distributed between the three previous diets in the five weeks before slaughtering. At the abattoir, no change was detected in caecal pH, but increased concentrations (p < 0.05) of formic and lactic acid were found with the NPB and PB treatments. The total SCFA concentration was higher with the PB compared to the control diet (p = 0.002) with a lower percentage of branched chain fatty acids. Both acidified diets decreased enterobacteria in the caecum but did not modify lactobacilli. NPB treatment decreased Salmonella seroprevalence (p < 0.001). A significant (p < 0.05) increase in Salmonella faecal shedding was found related to the stress previous to slaughter with the control group and PB, but not in the NPB group. More studies will be needed to confirm the usefulness of protected acids to prevent Salmonella prevalence and shedding at the abattoir.

Organic acids for performance enhancement in pig diets

Organic acids and their salts appear to be potential alternatives to prophylactic in-feed antibiotics and growth promoters in order to improve the performance of weaned piglets, fattening pigs and reproductive sows, although their growth-promoting effects are generally less than that of antibiotics. Based on an analysis of published data, the growth-promoting effect of formates, fumarates and citrates did not differ in weaned piglets. In fattening pigs, formates were the most effective followed by fumarates, whereas propionates did not improve growth performance. These acids improved the feedgain ratio of both weaned piglets and fattening pigs. In weaned piglets, the growth-promoting effects of dietary organic acids appear to depend greatly on their influence on feed intake. In sows, organic acids may have anti-agalactia properties. Successful application of organic acids in the diets for pigs requires an understanding of their modes of action. It is generally considered that dietary organic acids or their salts lower gastric pH, resulting in increased activity of proteolytic enzymes and gastric retention time, and thus improved protein digestion. Reduced gastric pH and increased retention time have been difficult to demonstrate, whereas improved apparent ileal digestibilities of protein and amino acids have been observed with growing pigs, but not in weaned piglets. Organic acids may influence mucosal morphology, as well as stimulate pancreatic secretions, and they also serve as substrates in intermediary metabolism. These may further contribute to improved digestion, absorption and retention of many dietary nutrients. Organic acid supplementation reduces dietary buffering capacity, which is expected to slow down the proliferation and|or colonization of undesirable microbes, e.g. Escherichia coli, in the gastro-ileal region. However, reduced scouring has been observed in only a few studies. As performance responses to dietary organic acids in pigs often varies, more specific studies are necessary to elucidate an explanation.

Effects of diets supplemented with organic acids and nucleotides on growth, immune responses and digestive tract development in weaned pigs

Sixty-eight (Experiment 1, 46 days feeding) and sixteen (Experiment 2, 21 days feeding) 21-days-old weaned pigs were allotted to four dietary treatments including control, 0.6% organic acids (OA), 0.1% nucleotides (NA) and 0.6% OA plus 0.1% NA for determining the dietary effects. In Experiment 1, OA enhanced peripheral blood mononuclear cells proliferation on day 28 and 46. The plasma immunoglobulin (Ig) A level was elevated by OA (p < 0.06) and NA (p < 0.07), respectively. In Experiment 2, NA increased plasma IgM level, and had an interactive effect with OA on ileal Peyer's patches and mesenteric lymph node lymphocyte proliferation, bile and plasma IgA levels, and jejunal crypt depth. NA elevated gastric pepsin and jejunal alkaline phosphatase activities, however, decreased ileal aminopeptidase N, sucrase or maltase activity. These results suggest that OA and NA have synergistically enhanced the gut-associated lymphocyte responses and NA modulates the digestive tract development of weaned pigs.