| Previous research has shown that an effective competitive exclusion (CE) or probiotic culture can accelerate the development of normal microflora in chicks. This accelerated development of a normal microflora can provide increased resistance to infection by some enteric bacterial pathogens. Our objective for the first set of experiments was to develop a CE culture for prophylaxis and reduced horizontal transmission of Salmonella enteritidis (SE) in broiler chickens. In the first study, seven members of the family Enterobacteriaceae and 2 lactic acid bacteria isolates, each capable of in vitro and in vivo inhibition of SE, were selected and combined to form the putative CE culture. In the first experiment, day-of-hatch chicks were randomly divided into four pens. All treated chicks were orally gavaged with the CE culture and 3 pens were treated with the CE culture in the drinking water for four consecutive days. Treated and control-non treated chicks were challenged with SE on day 4. All 3 groups of birds that were treated with the CE culture had a significant decrease (p<0.05) in cecal colonization compared with non-CE-treated SE-challenged chicks. These results suggest that a relatively simple and defined CE culture can reduce SE colonization in neonatal chicks.Spray application offers low-cost and efficient application of biologics and reduced concerns regarding diverse water quality and medicator/proportioner function. The objective of this study was to evaluate the spray application of a Lactobacillus-based probiotic on Salmonella enteritidis (SE) colonization in broiler chickens. Day-of-hatch chicks were challenged with Salmonella enteritidis (SE) by oral gavage alone, challenged with SE and treated by coarse spray application of a commercially-available Lactic-acid bacterial probiotic (FM-B11(TM)), or challenged with SE and treated with B11 continuously in the drinking water (DW). Five days post-challenge, cecal tonsils were collected for presence or absence of SE. In Exp. 1, probiotic treatment by either spray or DW application significantly (p<0.05) reduced SE recovery (55% and 50% respectively controls 85%) when chicks were held for 8h prior to challenge and placement. Similarly, when probiotic spray treatment or water treatment and challenge occurred simultaneously, with placement 8h after treatment, a marked and significant reduction of SE recovery was noted after 5d (10% and 40% respectively, controls 55%). In Exp. 2, when probiotic spray treatment and challenge occurred simultaneously, with placement 8h after treatment, a significant reduction of SE recovery was again noted in both the spray and DW application (80% controls, 15% spray, 15% DW). Taken together, these results suggest that spray application of B11, when performed in the manner described above, can be effective for protection of chicks against Salmonella infection.The results from these studies suggest that a defined, Lactobacillus-based probiotic culture can reduce SE infection in broiler chicks. These results also suggest that when this probiotic culture is used in combination with an effective organic acid mixture a further reduction in SE infection in broiler chicks is observed. Spray application of this probiotic culture is also a viable alternative for administration of this culture.In subsequent experiments, the efficacy of a refined Lactobacillus -based probiotic culture was tested in combination with an effective organic acid mixture (OA) on Salmonella enteritidis (SE) infection in broiler chicks. In experiment 1, chicks were challenged by oral gavage with SE, held in chick boxes for 2 h, and randomly assigned to either untreated control or continuous OA treatment in the drinking water. Crop and cecal tonsils were cultured at 48 h and 5 d post-challenge for recovery of SE. Recovery of SE in the crop and cecal tonsils at 48 h was significantly (p<0.05) lower in the OA treated group as compared to control chickens but not different at 5d. In exps. 2 and 3, chicks were SE challenged, held in chick boxes for 2 h, and randomly assigned to either untreated control, probiotic, OA, or probiotic + OA. After 24 or 48 h, crop and cecal tonsils were cultured for the presence or absence of SE. After 24 h, probiotic or probiotic + OA significantly reduced SE recovery from the crop as compared to controls. All treatments reduced SE recovery from the cecal tonsils at 24 h. SE recovery from probiotic and or probiotic + OA groups was significantly lower than the controls in the cecal tonsils. These data suggest that combination treatment with the selected OA and Lactobacillus-based probiotic culture is more effective than individual treatment for Salmonella reduction in chicks. |
