Biomedical subjects

A Hinton

Publications and source records attributed to A Hinton.

61 records · Page 4Linked to original sources

PubMedDate not supplied

Biological control of Salmonella typhimurium in young chickens.

The effect of dietary lactose and anaerobic cultures of cecal microflora of mature chickens on the colonization of young broiler chickens by Salmonella typhimurium was evaluated. Newly hatched chicks were given either no treatment (controls), anaerobic cecal cultures, lactose (2.5%) in the drinking water, or both anaerobic cultures and lactose. Chicks were challenged per os at 3 days of age with either 10(6) or 10(8) S. typhimurium resistant to nalidixic acid and novobiocin. On day 10, the cecal contents of the chicks were examined for S. typhimurium, pH, short-chained volatile fatty acids (VFAs), undissociated VFAs, and lactic acid. Chicks given either lactose alone or cecal anaerobes alone had significantly (P less than 0.05) fewer S. typhimurium recovered from their ceca than the controls. Chicks given the combination of dietary lactose and cecal anaerobes had significantly fewer S. typhimurium recovered from their ceca than the chicks given dietary lactose or cecal anaerobes alone. Chicks given lactose had significant (P less than 0.05) increases in the lactic acid concentration of their cecal contents. Increased lactic acid concentrations were directly correlated to decreased cecal pH values and caused a reduction in the total concentration of VFAs but a significant (P less than 0.05) increase in the undissociated form of some VFAs.

Animals↗

PubMedDate not supplied

Effect of dietary lactose on Salmonella colonization of market-age broiler chickens.

The effect of providing lactose in feed and inoculation with volatile fatty acid-producing anaerobic cultures (AC) of cecal flora on Salmonella typhimurium colonization was evaluated in broilers. One-day-old chicks were divided into four groups and provided 1) no lactose, no AC; 2) AC, no lactose; 3) AC and lactose on days 1-10; or 4) AC and lactose on days 1-40. All groups were challenged per os with 10(6) Salmonella on day 3 and with 10(8) Salmonella on day 33. Salmonella growth in the cecal contents was significantly decreased (P less than 0.01) on day 10 in the chicks provided lactose from day 1-10. However, after the removal of lactose from the diet, the chicks were susceptible to Salmonella colonization. The number of Salmonella in the ceca was significantly reduced (P less than 0.05) in the chicks provided lactose throughout the 40-day growing period. Dietary lactose decreased the pH of the cecal contents and was accompanied by marked increases in the concentrations of undissociated bacteriostatic volatile fatty acids in the cecal contents.

Animals↗

PubMedDate not supplied

Intracloacal Salmonella typhimurium infection of broiler chickens: reduction of colonization with anaerobic organisms and dietary lactose.

The combined effect of treatments with dietary lactose plus anaerobic organisms on cecal colonization of broiler chicks by Salmonella typhimurium was evaluated. Chickens treated with a combination of anaerobic organisms and 7% dietary lactose were resistant to cecal colonization by S. typhimurium. The number of recoverable S. typhimurium cells per gram of cecal contents taken on days 10 and 15 after infection was significantly reduced. Treatment with anaerobes without the addition of lactose did not effectively control cecal colonization. Intracloacal inoculations with bacterial concentrations that varied by 10,000-fold resulted in roughly similar levels of colonization. The treatments resulted in reduced cecal pH and elevated levels of undissociated volatile fatty acids. Statistically significant correlations (P less than 0.01) were observed between the S. typhimurium concentrations in cecal material and the concentrations of undissociated fatty acids (r = -0.79, and between the bacterial counts and pH (r = 0.72).

Animals↗

PubMedDate not supplied

Synergism of lactate and succinate as metabolites utilized by Veillonella to inhibit the growth of Salmonella typhimurium and Salmonella enteritidis in vitro.

The inhibition of salmonellae growth by a Veillonella bacterium isolated from the cecal contents of adult chickens was examined. The Veillonella isolate was grown on an agar medium supplemented with 175 mumol of lactate or succinate/ml. Either 0, 100, 125, 150, or 175 mumol of succinate/ml was added to the lactate medium; either 0, 100, 125, 150, or 175 mumol of lactate/ml was added to the succinate medium; and the pH of all media was adjusted to 6.0. Agar overlays of Veillonella cultures grown on the media were inoculated with Salmonella typhimurium or S. enteritidis. The largest zones of inhibition of salmonellae growth were produced by Veillonella cultures grown on medium supplemented with 175 mumol/ml of both lactate and succinate. The widths of the zones of inhibition decreased as the concentration of lactate was reduced in the succinate medium and as the concentration of succinate was reduced in the lactate medium. Analyses of lactate broth and succinate broth inoculated with Veillonella indicated that inhibition of salmonellae growth on the agar media was related to the production of volatile fatty acids by Veillonella, the presence of residual succinate in the media, and the final pH of the media.

Analysis of Variance↗

PubMedDate not supplied

Effect of selected antibiotics and anticoccidials on Salmonella enteritidis cecal colonization and organ invasion in Leghorn chicks.

One-day-old leghorn chicks were placed in floor pens on previously used poultry litter (potentially providing exposure to normal chicken enteric flora) for 7 days and provided feed containing one of several antibiotics or anticoccidials. On day 7, all groups were challenged orally with an isolate of Salmonella enteritidis (10(6) colony-forming units) that was resistant to bacitracin, novobiocin, nalidixic acid, and nitrofurazone. All chicks were killed on day 13, and liver, spleen, and cecal tonsils were cultured. Dietary administration of novobiocin (0.385 g/kg) caused a significant increase (P < 0.05) in positive chick colonization rate (either liver and spleen or cecal tonsils) compared with the unmedicated controls. Similarly, chicks administered dietary nitrofurazone (0.3 g/kg) were infected with S. enteritidis at a significantly greater frequency than the unmedicated controls. A significant decrease in cecal volatile fatty acid concentration, previously shown to influence susceptibility to selected enteric pathogens, was observed in the novobiocin- and nitrofurazone-treated groups. Treatment with chlortetracycline (11.4 g/kg), monensin (0.91 g/kg), or nicarbazin (0.49 g/kg) had no effect on S. enteritidis invasion or colonization. Bacitracin (0.49 g/kg) significantly increased S. enteritidis cecal colonization rate when administered continuously throughout the study. These data support and extend previous investigations involving other salmonellae and indicate that selected antibiotics may increase the severity and frequency of S. enteritidis colonization and invasion rate in leghorn chicks.

Animals↗

PubMedDate not supplied

Effectiveness of dietary propionic acid in controlling Salmonella typhimurium colonization in broiler chicks.

Newly hatched broiler chicks were provided a corn/soybean meal-based ration treated with propionic acid at 30 mumol/g of feed ration. At 3 days of age, the chicks were challenged orally with 10(4) Salmonella typhimurium. Crop contents from 4-day-old chicks that were provided dietary propionic acid contained significantly higher concentrations of propionic acid (4.0 to 6.8 mumol/g crop contents) than crops from challenged control chicks provided untreated feed (0.9 to 1.5 mumol/g crop contents). Provision of dietary propionic acid on feed as a dry powder in five trials or a liquid application in three trials had no significant effect on crop or cecal pH. Significant decreases in Salmonella in the crop and ceca were detected in one trial, but the decreases were likely the result of the presence of anti-salmonellae bacteria rather than the dietary propionic acid. Results indicate that propionic acid in the feed was ineffective in reducing Salmonella infection in the crop and ceca.

Animals↗

PubMedDate not supplied

Protective effect of used poultry litter and lactose in the feed ration on Salmonella enteritidis colonization of leghorn chicks and hens.

The effect of dietary administration of lactose and used poultry litter, containing cecal and fecal droppings from adult broilers, was evaluated for protective effects against Salmonella enteritidis colonization in leghorn chicks and 16-week-old hens. The addition of used litter as 5% of the feed ration significantly decreased (P < 0.01) Salmonella cecal and organ colonization in the chicks. Provision of used litter or used litter and lactose in the feed failed to provide protection against Salmonella colonization in the hens. The results indicated that resistance to S. enteritidis colonization may be effectively increased in leghorn chicks by exposure to adult intestinal flora present in used litter. Furthermore, the results suggest that microbiological strategies employing adult intestinal microflora that increase Salmonella colonization resistance in young chicks may be ineffective in older hens.

Animal Feed↗