The aim of this work was to investigate the effect of inclusion levels of a 5-bacterial species probiotic in broiler nutrition. Five hundred twenty-five 1-d-old male Cobb broilers were allocated in 5 experimental treatments for 6 wk. The experimental treatments received a corn-soybean coccidiostat-free basal diet and depending on the addition were labeled as follows: no addition (C), 10(8) cfu probiotic/kg of diet (P1), 10(9) cfu probiotic/kg of diet (P2), 10(10) cfu probiotic/kg of diet (P3), and 2.5 mg of avilamycin/kg of diet (A). Each treatment had 3 replicates of 35 broilers each. Treatment effects on broiler growth performance and biomarkers such as ileal and total tract nutrient digestibility, plasma Ig concentration, and cecal microflora composition were determined. Differences among treatments were considered significant when P < or = 0.05. Overall BW gain was significantly higher in treatment P1 (2,293 g) compared with P2 (2,163 g), C (2,165 g), and P3 (2,167 g), with A (2,230 g) being intermediate and not different from P1. Overall feed conversion ratio values were similar and significantly better for P1 (1.80) and A (1.80) compared with P2 (1.87), C (1.89), and P3 (1.92). Ileal apparent digestibility coefficients (ADC) of CP and ether extract were higher in A. Generally, treatments A and P1 showed an improved total tract ADC for DM, organic matter, ash, ether extract, and AME(n) values. The total tract ADC of CP was higher in P1, C, and P2. There were no differences between treatments regarding plasma Ig in 14- and 42-d-old broilers. Treatments P2 and P3 were effective at beneficially modulating cecal microflora composition. In particular, the lower cecal coliform concentration (log cfu/g of wet digesta) was seen in P2 (6.12) and P3 (4.90) in 14- and 42-d-old broilers, respectively, whereas at 42 d, P3 and P2 had the highest Bifidobacterium (8.31; 8.08) and Lactobacillus concentrations (8.20; 7.86), respectively. It is concluded that probiotic inclusion level had a significant effect on broiler growth responses, nutrient ADC, AME(n), and cecal microflora composition.

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Coccidiosis is an inherent risk in the commercial broiler industry and inflicts devastating economic losses to poultry operations. Probiotics may provide a potential alternative to the prophylactic use of anticoccidials in commercial production. This study evaluated the effects of probiotic applications (feed and water) on bird performance and resistance to a mixed Eimeria infection in commercial broilers. On day of hatch, 1,008 commercial male broilers (Cobb 500) were assigned to 1 of 6 treatments (8 replicate floor pens; 21 birds/pen), including noninfected negative control (NEG), Eimeria-infected positive control (POS), anticoccidial control (0.01% salinomycin, SAL), intermittent high-dose water-applied probiotic (WPI), continuous low-dose water-applied probiotic (WPC), and feed-supplemented probiotic (FSP). On d 15, all birds except those in NEG were challenged with a mixed inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Measurements were taken on d 7, 15, 21, 28, 35, and 42. Fecal samples were collected from d 20 to 24 for oocyst counts, and lesion scores were evaluated on d 21. Data were analyzed using the Fit Model platform in JMP Pro 10.0 (SAS Institute Inc.). Differences in experimental treatments were tested using Tukey's honestly significant difference following ANOVA with significance reported at P ≤ 0.05. Overall, NEG birds outperformed all other groups. For performance, the probiotic groups were comparable with the SAL-treated birds, except during the 6 d immediately following the Eimeria species challenge, where the SAL birds exhibited better performance. The WPC birds had lower duodenal and jejunal lesion scores, indicating a healthier intestine and enhanced resistance to Eimeria species compared with POS. Birds in the WPI treatment shed fewer oocysts in the feces, although this was not a trend for all of the probiotic treatment groups. The results of this study suggest probiotic supplementation without anticoccidials can enhance performance and help alleviate the negative effects of a mixed Eimeria infection.

Coccidiosis is endemic in the commercial broiler industry capable of inflicting devastating economic losses to poultry operations. Vaccines are relatively effective in controlling the disease; their efficacy could potentially be improved with concurrent use of probiotics as evaluated in this study using an Eimeria challenge. Day of hatch 400 Cobb-500 male broilers were assigned to one of four treatment groups including control (CON), vaccine-only gel application (VNC), probiotic-only gel application (NPC), and vaccine-plus-probiotic gel application (VPC). Birds were placed in floor pens (6 replicate pens/treatment, 16–17 birds/pen). NPC and VPC birds received the probiotics in the water on days 2–4, 8, 14–20, 22, 29, and 34–36. On day 15, birds were mildly challenged with 0.5 mL of a mixed oral inoculum of Eimeria sp. prepared with the coccidiosis vaccine at 10× the vaccination dose. Performance measurements were recorded on first day and weekly afterwards, and lesion scores were evaluated 6 days post-challenge. Overall, the probiotics and coccidiosis vaccine resulted in an enhanced protective effect against the challenge, with VPC birds exhibiting lower lesion scores in the duodenum than VNC or NPC birds. Birds in the VPC treatment also demonstrated higher weight gains during days 1–15, days 7–15, and days 21–28 when compared to the VNC birds. These results suggest that the combination of probiotics and coccidiosis vaccines could enhance performance and provide an additional protective effect against a mixed Eimeria challenge.

Abstract. The trial involved 684 Cobb 500 broiler chicks in order to investigate the effects of probiotics and phytogenic additives on performance, gut morphology and cecal microbial concentrations. Birds were assigned to three treatments: control feed, treatment with addition of probiotics in feed and water and treatment with addition of phytogenic blend in feed. The results showed a significant improvement (P<0.01) in body weight gain and a numerical, but non significant (P>0.05) improvement in feed conversion ratio by adding both probiotics and phytogenics in feed. There were no statistically significant differences among treatments regarding total aerobes, anaerobes, lactic acid bacteria, bifidobacteria, enterococci, and Escherichia coli populations (P>0.05) in cecum of broilers. The gut morphology examination showed that probiotics had beneficial effect on jejunum morphology causing a significant (P<0.005) increase in villus height and villus surface area compared to other two groups. On the other hand, phytogenic additive had no effect (P>0.05) on villus height or villus surface area, but reduced the villus/crypt ratio (P<0.05), which may indicate that the improved production results in the group with added phytogenics are not directly connected with changes in gut integrity, but with other physiological mechanisms.