Effects of formic acid or calcium formate in feed on performance and microbiological characteristics of broilers

Supplementation with paraformic acid in the diet improved intestinal development through modulating intestinal inflammation and microbiota in broiler chickens

The aim of this study was to explore the effects of supplementing paraformic acid (PFA) to the diet of broiler chickens on intestinal development, inflammation, and microbiota. A total of 378 healthy 1-day-old Arbor Acres broilers with similar birth weight were used in this study, and randomly assigned into two treatment groups. The broiler chickens were received a basal diet or a basal diet supplemented with 1,000 mg/kg PFA. Results showed that PFA supplementation increased (P < 0.05) small intestinal villus height and villus height/crypt depth ratio, elevated intestinal mucosal factors (mucin 2, trefoil factor family, and zonula occludens-1) concentrations, and upregulated mNRA expression of y + L amino acid transporter 1. Moreover, PFA supplementation decreased (P < 0.05) the concentrations of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-10), activities of caspase-3 and caspase-8, and mNRA expressions of Toll-like Receptor 4, nuclear factor-kappa B, Bax, and Bax/Bcl-2 ratio in small intestinal mucosa. Dietary PFA supplementation also increased (P < 0.05) alpha diversity of cecal microbiota and relative abundance of Alistipes. The present study demonstrated that supplementation of 1,000 mg/kg PFA showed beneficial effects in improving intestinal development, which might be attributed to the suppression of intestinal inflammation and change of gut microbiota composition in broiler chickens. These findings will aid in our knowledge of the mechanisms through which dietary PFA modulates gut development, as well as support the use of PFA in poultry industry.

Defined single-gene and multi-gene deletion mutant collections in Salmonella enterica sv Typhimurium

We constructed two collections of targeted single gene deletion (SGD) mutants and two collections of targeted multi-gene deletion (MGD) mutants in Salmonella enterica sv Typhimurium 14028s. The SGD mutant collections contain (1), 3517 mutants in which a single gene is replaced by a cassette containing a kanamycin resistance (KanR) gene oriented in the sense direction (SGD-K), and (2), 3376 mutants with a chloramphenicol resistance gene (CamR) oriented in the antisense direction (SGD-C). A combined total of 3773 individual genes were deleted across these SGD collections. The MGD collections contain mutants bearing deletions of contiguous regions of three or more genes and include (3), 198 mutants spanning 2543 genes replaced by a KanR cassette (MGD-K), and (4), 251 mutants spanning 2799 genes replaced by a CamR cassette (MGD-C). Overall, 3476 genes were deleted in at least one MGD collection. The collections with different antibiotic markers permit construction of all viable combinations of mutants in the same background. Together, the libraries allow hierarchical screening of MGDs for different phenotypic followed by screening of SGDs within the target MGD regions. The mutants of these collections are stored at BEI Resources (www.beiresources.org) and publicly available.

Effect of the commercial product Lumance™, a combination of partly esterified organic acids and plant extracts, on the productive performance of broiler chickens

The present study was conducted to determine the effect of dietary supplementation of organic acids combined with synergistic components, using a commercial product Lumance™ (Innovad NV, Belgium) containing esterified butyrins, propionic acid and sorbic acid, with medium chain fatty acids (capric, caprylic, and lauric acid) and plant extracts, on the productive performance and mortality of growing broiler chickens. A total of 492, one day old broiler chicks (Ross 308) were randomly allocated to four experimental treatments either with an unsupplemented control or 0.05, 0.1 or 0.15% organic acid mixture in a pelleted corn/soyabean meal diet, which were offered ad libitum until 35 days of age. Results showed that birds in the 0.1% supplemented diet group gave significantly higher (P < 0.05) body weights during the first two weeks of age and increased weight gain during the first three weeks of age. The inclusion had no effect on broiler mortality.

Chemical treatment of animal feed and water for the control of Salmonella

The control of Salmonella in animal feedstuffs is important, principally to protect the human food chain from contamination by Salmonella derived from infected animals. The transmission of Salmonella from animal feeds to animals, and onward to human food products, has been convincingly documented. This is especially important for chicken breeding and laying flocks and pigs, in view of the consequences of recent or imminent control legislation in the European Union. Animal feed ingredients, particularly animal and plant-derived protein meals, are frequently contaminated with Salmonella either from source or from processing plant, and recontamination in compounding mills is an additional problem. Several complementary strategies have been used to control this feed contamination, and these include a range of chemical treatments. The principal agents used are as follows: organic acids and their salts, formaldehyde, and bacterial membrane disruptors such as terpenes and essential oils. Experimental agents include chlorate compounds. Many products use blends of agents from the same or different chemical groups to achieve synergistic or combination effects. The present review draws upon published and company data to describe the various modes of action and efficacies of different chemical agents delivered in feed or in drinking water against Salmonella occurring in feed or in livestock environments. Reasons for the failure of protection are explored, along with problems in usage such as corrosion and reduced palatability. Given the wide array of products available with contrasting modes of action, the need for standardized tests of efficacy is also discussed.

Effect of enzyme supplementation and acidification of diets on nutrient digestibility and growth performance of broiler chicks

Two experiments were conducted to examine the effects of alpha-galactosidase supplementation and acidification of diets on nutrient digestibility and growth performance of broiler chicks. In experiment 1, dietary treatments consisted of feeding a low-energy basal diet (2.74 Mcal of ME/kg) alone, the basal diet supplemented with 1,724 units of alpha-galactosidase per kg, the basal diet supplemented with 2% citric acid, or the basal diet supplemented with both. alpha-Galactosidase significantly increased feed intake, weight gain, AME(n) of the diets, and retention of CP and neutral detergent fiber (NDF) (P < 0.05). Citric acid significantly increased the retention of DM, CP, and NDF, but decreased feed intake and weight gain. The greatest values for DM and NDF retention and for AME(n) were obtained with the combination of alpha-galactosidase plus citric acid. In experiment 2, chicks were fed diets with 2 levels of energy (2.74 or 3.11 Mcal/kg), 2 levels of citric acid (0 or 1.5%), and 2 levels of alpha-galactosidase (0 or 1,724 units/kg) in a 2 x 2 x 2 factorial arrangement of treatments. alpha-Galactosidase significantly increased the reducing sugar concentration in the crop content, whereas citric acid decreased the pH and increased the reducing sugar concentration in the crop content. Citric acid decreased the gain to feed ratio in the absence but not in the presence of alpha-galactosidase. The data from these studies indicate that acidification of diet improves the efficacy of alpha-galactosidase.

The use of organic acids to combatSalmonellain poultry: a mechanistic explanation of the efficacy

Salmonella is a human pathogen that is commonly found in poultry products. It is possible to decrease chicken carcass and egg contaminations by adding organic acids to the feed or drinking water at appropriate times. Medium-chain fatty acids are more antibacterial against Salmonella than short-chain fatty acids. The antibacterial effect of these acids is species specific. Bacteria that are unable to decrease intracellular pH accumulate organic acid anions in accordance with the pH gradient across their cell membranes. The short-chain fatty acid butyrate specifically down-regulates expression of invasion genes in Salmonella spp. at low doses. Also medium-chain fatty acids and propionate decrease the ability of Salmonella spp. to invade epithelial cells, in contrast to acetic acid. Because not all bacteria are affected in a similar fashion by organic acids, it may be possible to use probiotic and prebiotic bacteria to achieve beneficial effects. If diets can be designed to stimulate organic acid production in the caecum, it may be possible to control Salmonella spp. via even easier and more cost-effective measures, compared with addition of acids to feed or drinking water.

Effects of Formalin Feeding or Administering into the Crops of White Leghorn Cockerels on Hematological and Biochemical Parameters

Formalin administered (15 and 20 mL) into the crops of White Leghorn cockerels resulted in behavioral alterations, included depression, dullness, staggering, somnolence, anorexia, and decreased frequency of crowing. A significant decrease was observed in red blood cell counts, hemoglobin concentration, packed cell volume, and leukocyte counts in birds fed higher levels of formalin. Decreasing and increasing trends in concentrations of serum proteins and enzymes, respectively, were observed with increases in formalin doses. Significantly lower blood glucose and testosterone levels and significantly (P < 0.05) higher blood urea and creatinine concentrations were observed in birds fed higher formalin levels. No gross or microscopic lesions were observed in the birds fed different levels of formalin mixed in feed. These changes suggested that the formalin mixed in feed might have evaporated, and, hence, the amount ingested might have been too low to induce pathological changes. It was concluded from the present study that formalin mixed up to 5 mL/kg of feed, corresponding to 10 mL/bird of 3% formalin in drinking water by crop tube had no adverse effects on the health of White Leghorn cockerels.

Effect of acidified feed on susceptibility of broiler chickens to intestinal infection by Campylobacter and Salmonella

Consumption of poultry meat is associated with human Campylobacter and Salmonella infections. One way to control the presence of these bacteria in broiler flocks is to make chickens less susceptible for colonisation. Acidification of feed may be a tool to reduce the Campylobacter and Salmonella carriage in broiler chickens. In the present experiments an acidified feed with high levels of organic acid, 5.7% lactic acid and 0.7% acetic acid, was applied. In an in vitro experiment the reduction or growth of Campylobacter and Salmonella was measured after addition of 10(7)cfu of these bacteria into a conventional broiler feed, acidified feed and fermented feed, whereas the numbers of Salmonella increased in non-acidified feed. The number of Campylobacter decreased 2-3 (10)log cfu. In the acidified and fermented feed a complete reduction of Campylobacter was observed within 20 min, and a total Salmonella reduction started after 1h, and was complete after 2h. Subsequently, an in vivo experiment with 100 individually housed broiler chickens showed that chickens fed acidified feed were less susceptible to an infection with Campylobacter than were chickens fed conventional feed. The size of reduction was however limited. The susceptibility for Salmonella colonisation was not affected by acidified feed. It is concluded that the role for acidified feed in the control of Campylobacter and Salmonella is limited.

Microencapsulated Short-Chain Fatty Acids in Feed Modify Colonization and Invasion Early After Infection with Salmonella Enteritidis in Young Chickens

Short-chain fatty acids (SCFA) are widely used as feed additives in poultry for the control of pathogenic bacteria, such as Salmonella enteritidis. Recently, a new range of products was developed in which SCFA are encapsulated in mineral carriers, resulting in a slow release during the transport of these carriers through the intestinal tract. To test the efficacy of this type of products against early colonization after Salmonella infection in poultry, a challenge experiment with S. enteritidis was performed. Five groups of 20 chickens were given feed with no supplement or feed supplemented with acetic acid (0.24%), formic acid (0.22%), or propionic acid (0.27%) as film-coated microbeads or butyric acid (0.15%) as spray-cooled microcapsules. The 5 groups were challenged with 5 x 10(3) cfu S. enteritidis at d 5 and 6 posthatch, and samples of ceca, liver, and spleen were taken at d 8 and analyzed for the number of colony-forming units of Salmonella per gram of tissue. Feed supplementation with acetic acid, and to a lesser extent formic acid, resulted in an increase of colonization of ceca and internal organs. Birds receiving propionic acid-coated microbeads as feed supplement were colonized with Salmonella to the same extent as controls. Butyric acid-impregnated microbeads in the feed, however, resulted in a significant decrease of colonization by S. enteritidis in the ceca but not in liver and spleen.

Influence of a novel oxy-halogen compound on early growth and nitrogen retention of broiler chickens challenged with Salmonella

The potential of a novel oxy-halogen compound (OHC) to alter early growth and nitrogen retention of broiler chickens challenged with Salmonella was evaluated. Three hundred and twenty female broiler chicks (Arbor Acres x Arbor Acres) were weighed and distributed randomly within a 2 x 4 factorial arrangement of treatments. Main effects examined were the presence or absence of Salmonella typhimurium (ST) inoculation and OHC treatment. At hatching, 80 chicks were placed in electrically heated brooder batteries in each of four identical isolation rooms. Chicks designated to receive 100 microL of an oral inoculum containing 10(5) ST cfu at 3 days of age were in two of the rooms, and uninoculated chicks were raised in the other two rooms. Four replicates of 10 chicks each received drinking water containing either 0, .05, .1, or .5% OHC for each level of ST. Chicks administered .05% OHC exhibited enhanced (P < or = .01) growth at 7 and 14 days of age when compared with control values. A significant OHC by ST interaction was observed at 7 (P < or = .0001) and 14 (P < or = .03) days of age. Feed utilization was improved (P < or = .01) by OHC administration (.05 and .1%) from hatching to 7 days of age. The administration of OHC reduced (P < or = .01) nitrogen excretion and enhanced (P < or = .01) nitrogen retention by chicks at Day 7. Cecal ST log10 counts at 7 days of age for chicks given water containing 0, .05, or .1% OHC were 4.72, 3.93, and 3.74, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnesium sulfate effects on coliform bacteria reduction in the intestines, ceca, and carcasses of broiler chickens

The objective of the study was to evaluate the effects of MgSO4 on intestinal and cecal content reduction with subsequent effects on carcass weight loss and coliform bacterial counts in the intestine and ceca, and on the processed carcass. Four hundred and eighty broiler chicks, 49 days of age, were fed MgSO4 at levels of 0, 2.5, 4.0, 5.5, 7.0, and 8.5 g/L via drinking water 24 h before processing. Samples from the intestinal and cecal contents and swabs from the processed carcass surface were plated for coliform bacteria colonization. The results indicated that carcass weight loss was not affected significantly by MgSO4, irrespective of the levels fed. The mean dressing percentage of the treated chicks was 64.9% compared with 65.2% for the controls. Although the reduction in the intestinal contents was not significant, the coliform bacterial counts declined from 1.4 x 10(6) to 1.4 x 10(4), a reduction of 2 logs when the MgSO4 was administered at 5.5 g/L. However, both the cecal contents and coliform bacteria were reduced significantly when the birds were given 5.5 g/L of MgSO4. The reduction of the coliform bacteria in the ceca was significant when compared with the control, an approximate reduction of 3 logs. Also, the bacterial counts on the carcass surface were nonsignificantly reduced from 2.2 x 10(4) to 2 x 10(3), a 1-log reduction. Correlation coefficients showed that as the contents of the intestine decreased, the coliform bacterial counts in the ceca and on the carcass surface decreased.(ABSTRACT TRUNCATED AT 250 WORDS)